date: 2017-06
title: NEW HEPATITIS DATA HIGHLIGHT NEED FOR URGENT GLOBAL RESPONSE

**21 APRIL 2017 \| GENEVA, AMSTERDAM** - New WHO data reveal that an estimated 325 million people worldwide are living with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection. The WHO Global hepatitis report, 2017 indicates that the large majority of these people lack access to life-saving testing and treatment. As a result, millions of people are at risk of a slow progression to chronic liver disease, cancer, and death.

"Viral hepatitis is now recognized as a major public health challenge that requires an urgent response," said Dr Margaret Chan, WHO Director-General. "Vaccines and medicines to tackle hepatitis exist, and WHO is committed to helping ensure these tools reach all those who need them."

# Increasing mortality, new infections

Viral hepatitis caused 1.34 million deaths in 2015, a number comparable to deaths caused by tuberculosis and HIV. But while mortality from tuberculosis and HIV has been declining, deaths from hepatitis are on the increase.

Approximately 1.75 million people were newly infected with HCV in 2015, bringing the global total of people living with hepatitis C to 71 million.

Although overall deaths from hepatitis are increasing, new infections of HBV are falling, thanks to increased coverage of HBV vaccination among children. Globally, 84% of children born in 2015 received the 3 recommended doses of hepatitis B vaccine. Between the pre-vaccine era (which, according to the year of introduction can range from the 1980s to the early 2000s) and 2015, the proportion of children under 5 years of age with new infections

fell from 4.7% to 1.3%. However, an estimated 257 million people, mostly adults born before the introduction of the HBV vaccine, were living with chronic hepatitis B infection in 2015.

# Epidemics in regions and "hotspots"

Hepatitis B levels vary widely across WHO regions with the WHO African Region and WHO Western Pacific Region sharing the greatest burden.

WHO Western Pacific Region: 6.2% of population (115 million people)

WHO African Region: 6.1% of population (60 million people)

WHO Eastern Mediterranean Region: 3.3% of population (21 million people)

WHO South-East Asia Region: 2% of population (39 million people)

WHO European Region: 1.6% of population (15 million people)

WHO Region of the Americas: 0.7% of population (7 million people)

Today, unsafe injections in health care settings and injecting drug use are considered to be the most common routes of HCV transmissions. HCV prevalence by WHO region is:

WHO Eastern Mediterranean Region: 2.3% of population (15 million people)

WHO European Region: 1.5% of population (14 million people)

WHO African Region: 1% of population (11 million people)

WHO Region of the Americas: 1% of population (7 million people)

WHO Western Pacific Region: 1% of population (14 million people)

WHO South-East Asia Region: 0.5% of population (10 million people)

# Treatment access is low

There is currently no vaccine against HCV, and access to treatment for HBV and HCV is still low.

WHO's Global Health Sector Strategy on viral hepatitis aims to test 90% and treat 80% of people with HBV and HCV by 2030.

The report notes that just 9% of all HBV infections and 20% of all HCV infections were diagnosed in 2015. An even smaller fraction – 8% of those diagnosed with HBV infection (1.7 million people) were on treatment, and only 7% of those diagnosed with HCV infection (1.1 million people) had started curative treatment during that year.

HBV infection requires lifelong treatment, and WHO currently recommends the medicine tenofovir, already widely used in HIV treatment. Hepatitis C can be cured within a relatively short time using the highly effective direct-acting antivirals (DAAs).

"We are still at an early stage of the viral hepatitis response, but the way forward looks promising," said Dr Gottfried Hirnschall, Director of WHO's Department of HIV and the Global Hepatitis Programme. "More countries are making hepatitis services available for people in need – a diagnostic test costs less than US\$ 1 and the cure for hepatitis C can be below US\$ 200. But the data clearly highlight the urgency with which we must address the remaining gaps in testing and treatment."

# Country progress

WHO's Global hepatitis report, 2017 demonstrates that despite challenges, some countries are taking successful steps to scale-up hepatitis services.

China achieved high coverage (96%) for the timely birth dose of HBV vaccines, and reached the hepatitis B control goal of less than 1% prevalence in children under the age of 5 in 2015. Mongolia improved uptake of hepatitis treatment by including HBV and HCV medicines in its National Health Insurance scheme, which covers 98% of its population. In Egypt, generic competition has reduced the price of a 3-month cure for hepatitis C, from US\$ 900 in 2015, to less than US\$ 200 in 2016. Today in Pakistan, the same course costs as little as US\$ 100.

Improving access to hepatitis C cure received a boost at the end of March 2017, when WHO prequalified the generic active pharmaceutical ingredient of sofosbuvir. This step will enable more countries to produce affordable hepatitis medicines.

# Baseline for elimination

WHO's Global hepatitis report, 2017 aims to provide a starting point for hepatitis elimination by indicating baseline statistics on HBV and HCV infections, including mortality, and coverage levels of key interventions. Hepatitis B and C – the 2 main types out of 5 different hepatitis infections – are responsible for 96% of overall hepatitis mortality.

Brazil and the World Hepatitis Alliance. It will be held on 1–3 November 2017 in São Paulo, Brazil.

Available from: <http://www.who.int/mediacentre/news/releases/2017/global-hepatitis-report/en/>


author: Thomas C Erren; Philip E Bourne\* To whom correspondence should be addressed. E-mail: <firstname.lastname@example.com>
date: 2007-05
references:
title: Ten Simple Rules for a Good Poster Presentation

Posters are a key component of communicating your science and an important element in a successful scientific career. Posters, while delivering the same high-quality science, offer a different medium from either oral presentations \[1\] or published papers \[2\], and should be treated accordingly. Posters should be considered a snapshot of your work intended to engage colleagues in a dialog about the work, or, if you are not present, to be a summary that will encourage the reader to want to learn more. Many a lifelong collaboration \[3\] has begun in front of a poster board. Here are ten simple rules for maximizing the return on the time-consuming process of preparing and presenting an effective poster.

# Rule 1: Define the Purpose

The purpose will vary depending on the status and nature of the work being presented, as well as the intent. Some posters are designed to be used again and again; for example, those making conference attendees aware of a shared resource. Others will likely be used once at a conference and then be relegated to the wall in the laboratory. Before you start preparing the poster, ask yourself the following questions: What do you want the person passing by your poster to do? Engage in a discussion about the content? Learn enough to go off and want to try something for themselves? Want to collaborate? All the above, or none of the above but something else? Style your poster accordingly.

# Rule 2: Sell Your Work in Ten Seconds

Some conferences will present hundreds of posters; you will need to fight for attention. The first impressions of your poster, and to a lesser extent what you might say when standing in front of it, are crucial. It is analogous to being in an elevator and having a few seconds to peak someone's interest before they get off. The sad truth is that you have to sell your work. One approach is to pose your work as addressing a decisive question, which you then address as best you can. Once you have posed the question, which may well also be the motivation for the study, the focus of your poster should be on addressing that question in a clear and concise way.

# Rule 3: The Title Is Important

The title is a good way to sell your work. It may be the only thing the conference attendee sees before they reach your poster. The title should make them want to come and visit. The title might pose a decisive question, define the scope of the study, or hint at a new finding. Above all, the title should be short and comprehensible to a broad audience. The title is your equivalent of a newspaper headline—short, sharp, and compelling.

# Rule 4: Poster Acceptance Means Nothing

Do not take the acceptance of a poster as an endorsement of your work. Conferences need attendees to be financially viable. Many attendees who are there on grants cannot justify attending a conference unless they present. There are a small number of speaking slots compared with attendees. How to solve the dilemma? Enter posters; this way everyone can present. In other words, your poster has not been endorsed, just accepted. To get endorsement from your peers, do good science and present it well on the poster.

# Rule 5: Many of the Rules for Writing a Good Paper Apply to Posters, Too

Identify your audience and provide the appropriate scope and depth of content. If the conference includes nonspecialists, cater to them. Just as the abstract of a paper needs to be a succinct summary of the motivation, hypothesis to be tested, major results, and conclusions, so does your poster.

# Rule 6: Good Posters Have Unique Features Not Pertinent to Papers

The amount of material presented in a paper far outweighs what is presented on a poster. A poster requires you to distill the work, yet not lose the message or the logical flow. Posters need to be viewed from a distance, but can take advantage of your presence. Posters can be used as a distribution medium for copies of associated papers, supplementary information, and other handouts. Posters allow you to be more speculative. Often only the titles or at most the abstracts of posters can be considered published; that is, widely distributed. Mostly, they may never be seen again. There is the opportunity to say more than you would in the traditional literature, which for all intents and purposes will be part of the immutable record. Take advantage of these unique features.

# Rule 7: Layout and Format Are Critical

Pop musician Keith Richards put the matter well in an interview with *Der Spiegel* \[4\]: "If you are a painter, then the most important thing is the bare canvas. A good painter will never cover all the space but will always leave some blank. My canvas is silence." Your canvas as poster presenter is also white space. Guide the passerby's eyes from one succinct frame to another in a logical fashion from beginning to end. Unlike the literature, which is linear by virtue of one page following another, the reader of a poster is free to wander over the pages as if they are tacked to the poster board in a random order. Guide the reader with arrows, numbering, or whatever else makes sense in getting them to move from one logical step to another. Try to do this guiding in an unusual and eye-catching way. Look for appropriate layouts in the posters of others and adopt some of their approaches. Finally, never use less than a size 24 point font, and make sure the main points can be read at eye level.

# Rule 8: Content Is Important, but Keep It Concise

Everything on the poster should help convey the message. The text must conform to the norms of sound scientific reporting: clarity, precision of expression, and economy of words. The latter is particularly important for posters because of their inherent space limitations. Use of first-rate pictorial material to illustrate a poster can sometimes transform what would otherwise be a bewildering mass of complex data into a coherent and convincing story. One carefully produced chart or graph often says more than hundreds of words. Use graphics for "clear portrayal of complexity" \[5\], not to impress (and possibly bewilder) viewers with complex artistry. Allow a figure to be viewed in both a superficial and a detailed way. For example, a large table might have bold swaths of color indicating relative contributions from different categories, and the smaller text in the table would provide gritty details for those who want them. Likewise, a graph could provide a bold trend line (with its interpretation clearly and concisely stated), and also have many detailed points with error bars. Have a clear and obvious set of conclusions—after the abstract, this is where the passerby's eyes will wander. Only then will they go to the results, followed by the methods.

# Rule 9: Posters Should Have Your Personality

A poster is a different medium from a paper, which is conventionally dry and impersonal. Think of your poster as an extension of your personality. Use it to draw the passerby to take a closer look or to want to talk to you. Scientific collaboration often starts for reasons other than the shared scientific interest, such as a personal interest. A photo of you on the poster not only helps someone find you at the conference when you are not at the poster, it can also be used to illustrate a hobby or an interest that can open a conversation.

# Rule 10: The Impact of a Poster Happens Both During and After the Poster Session

When the considerable effort of making a poster is done, do not blow it on presentation day by failing to have the poster achieve maximum impact. This requires the right presenter–audience interaction. Work to get a crowd by being engaging; one engaged viewer will attract others. Don't badger people, let them read. Be ready with Rule 2. Work all the audience at once, do not leave visitors waiting for your attention. Make eye contact with every visitor.

Make it easy for a conference attendee to contact you afterward. Have copies of relevant papers on hand as well as copies of the poster on standard-sized paper. For work that is more mature, have the poster online and make the URL available as a handout. Have your e-mail and other demographics clearly displayed. Follow up with people who come to the poster by having a signup sheet.

The visitor is more likely to remember you than the content of your poster. Make yourself easy to remember. As the host of the work presented on the poster, be attentive, open, and curious, and self-confident but never arrogant and aggressive. Leave the visitors space and time—they can "travel" through your poster at their own discretion and pace. If a visitor asks a question, talk simply and openly about the work. This is likely your opportunity to get feedback on the work before it goes to publication. Better to be tripped up in front of your poster than by a reviewer of the manuscript.

Good posters and their presentations can improve your reputation, both within and outside your working group and institution, and may also contribute to a certain scientific freedom. Poster prizes count when peers look at your resume.

These ten rules will hopefully help you in preparing better posters. For a more humorous view on what not to do in preparing a poster, see \[6\], and for further information, including the opportunity to practice your German, see \[7\].

Thomas Erren's contributions to this piece are based on \[7\] and were stimulated by exchanges with Michael Jacobsen. Thanks also to Steven E. Brenner for useful input.

# References


abstract: The presence of mammary glands is the defining morphological feature of mammals. The recent assembly of the bovine genome and a report in *Genome Biology* that links the milk and lactation data of bovine and other mammalian genomes will help biologists investigate this economically and medically important feature.
author: Anthony V Capuco; R Michael Akers
date: 2009
institute: 1USDA-ARS, Bovine Functional Genomics Laboratory, Powder Mill, BARC-East, Beltsville, MD 20705, USA; 2Virginia Polytechnic Institute and State University, Department of Dairy Science, 2470 Litton-Reaves Hall, Blacksburg, VA 24061, USA
references:
title: The origin and evolution of lactation

# Minireview

The mammary gland has been a pivotal feature in the evolution and taxonomic classification of animal species, and it has even had a role in the acceptance of evolutionary theory. The presence and secretory capacity of the mammary gland provided the basis for the taxonomic grouping of species into the class Mammalia more than two centuries ago; and Darwin's explanation of how lactation may have evolved satisfied an early challenge to his theory of evolution by natural selection \[1\]. The challenge was that evolution of lactation was not feasible, because a neonate could not obtain a survival benefit from consuming the chance secretion of a rudimentary cutaneous gland. In response, Darwin hypothesized that mammary glands evolved from cutaneous glands that were contained within the brood pouches in which some fish and other marine species keep their eggs, and provided nourishment and thus a survival advantage to eggs of ancestral species. Two hundred years after Darwin's birth, the theory of evolution by natural selection remains a cornerstone of biology, as it has withstood this and other challenges. However, it is now clear that the mammary gland did not evolve from a brood pouch \[1\].

Milk nourishes the neonate and helps to establish immunological and endocrine competence in the offspring. The nutrient composition of milk varies dramatically across species, and it can also be strongly influenced by the stage of lactation. For example, the fat content of milk may be as high as 60% in seals and negligible during early lactation in wallabies \[2,3\]. Furthermore, milk in the tammar wallaby (*Macropus eugenii*) changes from a very dilute secretion containing primarily carbohydrate during early lactation to a more energy-dense milk that contains substantial quantities of protein and fat during later phases of lactation. Thus, the details of lactation have evolved to meet the diverse reproductive and environmental demands of different species. About 10,000 years ago, the domestication of plant and animal species led to the Neolithic Revolution, with its changes in societal interactions and the evolution of civilization. Milk and dairy products were tightly coupled to this cultural evolution, and dairying (then and now) provides an important source of food and fiber throughout the world.

Sequencing and assembly of the bovine genome, establishment of mammary transcriptome and proteome libraries, the discovery of single nucleotide polymorphisms \[4\], and discoveries and developments to come, are providing important tools for agricultural scientists to investigate the biology of lactation and to adopt genotype-based breeding schemes to select for desired traits. Moreover, comparative genomic studies enable evaluation of lactation across numerous and diverse mammalian species. Regardless of the perceived target species of this research, such knowledge improves our understanding of mammary gland biology and is applicable to normal and pathological states. Danielle Lemay and colleagues, in a recent report in *Genome Biology* \[5\], have taken this important step towards greater understanding through comparative genomics.

# Evolution of lactation

Lactation appears to be an ancient reproductive feature that pre-dates the origin of mammals. A cogent theory for the evolution of the mammary gland and lactation has been provided by Olav Oftedal \[1\]. The features of current mammals were gradually accrued through radiations of synapsid ancestors, and the mammary gland is hypothesized to have evolved from apocrine-like glands associated with hair follicles (Figure 1). Oftedal suggests that these glands evolved from providing primarily moisture and antimicrobials to parchment-shelled eggs to the role of supplying nutrients for offspring. Fossil evidence indicates that some of the therapsids and the mammalia-formes, which were present during the Triassic period more than 200 million years ago, produced a nutrient-rich milk-like secretion.

The capacity to supply fluid and perhaps nutrients to eggs would be promoted and enhanced by incorporation of antimicrobials into the fluid. These may have been antimicrobials already produced in the skin, as in amphibian skin, and evolutionary pressure would probably have fostered the incorporation of molecules such as lysozyme and iron-binding proteins into the secretion, components that are prevalent in milk. The disaccharide lactose (galactose β1–4 glucose) is contained in all milks, except for those of some marine mammals. Its synthesis is catalyzed in the mammary gland by lactose synthetase, an enzyme that is a complex of β1–4-galactosyl transferase and the regulatory subunit α-lactalbumin. Because α-lactalbumin evolved from lysozyme before the division of amniotes into synapsids and sauropsids (see Figure 1), the capacity to produce lactose was an ancient trait that preceded its utility in milk synthesis. It is likely that early milks primarily contained antimicrobial oligosaccharides and the prevalence of lactose as a component of milk arose only when α-lactalbumin was produced in sufficient quantity.

With the synthesis of lactose, these modified secretions would have provided nutrients to the egg. The evolution of the casein family of milk proteins in particular would provide calcium, phosphate and protein to hatchlings. Fossil records suggest that caseins were present during the Triassic, because the extensive bone and tooth development evident in the relevant species at stages before independent feeding would have required delivery of ample calcium. Given this evolutionary scenario, the composition of mammary secretions during early lactation in monotremes and marsupials is likely to be similar to that of the primitive milk of mammalian predecessors. The milk then converts to a more nutrient-rich source during later stages of lactation. The evolution of placenta-based reproduction displaced the function of milk as a source of water and nutrients for the egg, leading to secretion of a complex milk throughout lactation in eutherians (Figure 1).

Milk also enhances the survival of offspring by satisfying other needs, for example, by promoting immunological competence and endocrine maturation in the neonate \[6,7\]. In this regard, milk seems to provide for the immediate and long-term needs of the offspring. These needs can be highly species-specific. There are also behavioral and 'psychological' aspects of suckling and nurturing between mother (dam) and offspring that produce bonds that promote neonate survival. This is an aspect of lactation that is independent of the chemical and physical characteristics of milk.

# Systemic and local control of mammary function

Mammary gland development and function is subject to systemic and local control. In placental mammals, our understanding of this regulation has been advanced by decades of scientific inquiry, using physiological, molecular and genomic tools. In these mammals, development of the mammary gland during gestation generates abundant alveolar secretory cells. Differentiation of the secretory cells and the onset of copious milk synthesis and secretion are regulated to coincide with parturition. The combined effects of positive endocrine stimulators (prolactin, insulin, glucocorticoids, growth hormone and estradiol) are kept in check by the overriding negative influence of progesterone \[8\]. The decline in progesterone at parturition largely determines the onset of copious milk secretion, but regulation in marsupials differs from that in eutherians. The reproductive cycle in marsupials is characterized by a short gestation and a long lactation, during which the female will nurse offspring of different ages. Lactation in the tammar wallaby has been studied and, consistent with the marsupial reproductive strategy, is found to be insensitive to inhibition by progesterone \[2,9\]. The tammar wallaby offspring (joey) is born in an immature state at 26 days gestation. At birth it remains attached to the nipple for a period, during which it obtains a dilute, carbohydrate-rich milk. However, the composition of the milk changes significantly during lactaton to meet the demands of the developing joey. Moreover, the tammar has asynchronous concurrent lactation, during which the dam provides milk of differing composition from adjacent glands to feed two offspring of different ages and nutritional needs. This provides an example of local regulation of lactation.

Another clear example of local regulation is provided by lactation in the Cape fur seal (*Arctocephalus pusillus pusillus*), which is characterized by short suckling periods (2–3 days) on shore and lengthy foraging periods (about 20 days) at sea, during which maternal nutrient stores are replenished. In most eutherian species, milk secretion decreases in the absence of suckling, and this is accompanied by an increase in apoptosis and mammary involution, seemingly promoted by feedback inhibition from components of the unused milk. Lactation in the Cape seal has uncoupled the apoptotic response from decreased milk synthesis, so that the mammary gland simply shuts down during the long foraging periods and resumes secretion when suckling is resumed. The local factor recently implicated in this process is the milk protein α-lactalbumin. The α-lactalbumin in this group of seals (the otariid pinnipeds) apparently cannot promote apoptosis (or lactose synthesis) \[10\].

# Features of milk and mammary genes (the 'lactome')

Lemay *et al*. \[5\] used the *Bos taurus* genome sequence (draft 3.1, August 2006) and expression libraries derived from tissue obtained during various stages of mammary development and lactation status to identify unique milk proteins and mammary-related proteins. With the exception of four milk-protein gene clusters (casein genes, immunoglobulin genes, fibrinogen genes and genes encoding proteins of the milk fat globule), they found that milk-protein genes do not cluster with each other, but rather tend to cluster with other lactation genes. They also did not cluster by developmental stage or gene duplication, suggesting that these genes clustered to facilitate coordinate gene expression.

The bovine genome was compared with six other mammalian genomes: human, dog, mouse and rat (eutherians), opossum (marsupial) and platypus (monotreme). In general, milk and mammary genes were more conserved and seemed to evolve more slowly than others in the bovine genome, despite selective breeding for milk production. This supports the hypothesis that lactation has evolved to minimize the energy cost to the dam while maximizing survival of the neonate, thus promoting survival of the maternal-offspring pair. The most divergent proteins in the lactome were those with nutritional or immunological attributes, suggesting continuing selection of these genes to meet nutritional and pathogen challenges that are incurred by diverse environments and reproductive strategies. The most conserved genes were those for proteins of the milk fat globule membrane, confirming the essentiality of this mechanism for milk-fat secretion and indicating that the diversity in milk fat may be due to altered efficiency in secretion, not to inherent changes in the secretory process. Diversity in milk composition could not be explained by diversity of the encoded milk proteins; and although gene duplication may contribute to species variation, this is not a major determinant. Thus, other regulatory mechanisms must be involved. For example, on the basis of analysis of the opossum genome, Mikkelsen *et al*. \[11\] concluded that most of the genomic diversity between marsupials and placental mammals comes from non-coding sequences. These, or other factors that regulate the partitioning of nutrients, the interaction between mammary gland and supporting organs, or mammary gland metabolism, may be primary determinants of milk composition.

Expansion of comparative studies to include additional non-placental species and inclusion of non-coding regions of the genome is certain to provide additional insight into the regulation of mammary gland function and milk composition. For example, a systematic study of the role of microRNAs in mammary development and lactation is likely to be a fruitful area of investigation. Because no single species can provide an ample and sufficient model for the physiology of another, and because the potential gain in knowledge from comparative studies is great, the research community should not be species-centric. Continued research in mammary gland biology that incorporates comparative genomic and physiological studies of animals with varied and extreme adaptations to lactation will be necessary to provide insights into the development and regulation of mammary gland function, as well as the probable evolution of these processes.

Bovine genome coverage in BioMed Central:

**[The cattle genome reveals its secrets](http://jbiol.com/content/8/4/36):** *Burt DW*

**[The origin and evolution of lactation](http://jbiol.com/content/8/4/37):** *Capuco AV, Akers RM*

**[Back to Bermuda: how is science best served?](http://genomebiology.com/2009/10/4/105):** *Church DM, Hillier LW*


abstract: Given that the effectiveness of genome-wide association studies for finding disease genes is being debated, an alternative would be to look for diseases linked to inherited metabolic disorders.
author: Gregory A Petsko
date: 2009
institute: 1Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, USA
title: Guilt by association

It's a favorite device of politicians who wish to smear a rival candidate. The late, unlamented Democratic Senator Joseph McCarthy employed it, successfully, against leftists whose careers he wished to destroy. The Republicans tried, unsuccessfully, to use it against Barack Obama. In its simplest form, it involves branding someone a Communist, or a terrorist, or a criminal, because they have family or friends, or possibly just casual acquaintances, who are Communists, or terrorists, or criminals. It's called guilt by association.

It's been in the news lately because it's also a favorite tactic of genome biologists, but in this case its purposes are not sinister. Scientifically, it goes by the name of genome-wide association studies, though guilt by association is just as apt. It's an attempt to find connections between simple changes in the coding sequence of genes and the risk for developing complex diseases. A product of the human genome sequence (and, one could almost say, a means of ensuring job security for the hordes of sequencers who were responsible for that project), genome-wide association studies represent the first comprehensive attempt by the genomics community to demonstrate a big payoff, in terms of benefits to human health, for the enormous amounts that were spent on that original project.

If there were world enough and time, as Andrew Marvel (or was it Francis Collins?) would say, we would perform such studies simply by sequencing the complete genomes of large cohorts of people with, say, type II diabetes, or lung cancer, or schizophrenia, or Alzheimer's disease, and then letting the computational folks sift through the resulting reams of data to sort out the varying combinations of simple spelling mistakes in many different genes that give rise to autism, or stroke, and so on - and it's quite likely that, when sequencing costs come down sufficiently, this is exactly what we will do. In the meantime, though, the effort is more restricted.

The current approach relies on data from the International Human Haplotype Mapping (HapMap) Project, which aims to determine the prevalence of common polymorphisms in the human genome, and on the fact that genetic variance at one locus can predict with high probability genetic variance at an adjacent locus, typically over distances of 30,000 base pairs of DNA, making it possible to map the common variability - and, as we shall see, the key word here is 'common' - associated with the risk of a given disease simply by genotyping approximately 500,000 judiciously chosen markers in the genome of several thousand case subjects and comparing the frequency of those markers with genotypes of control subjects. Consequently, it has become relatively routine to identify common variants (for example, those that are present in more than 5% of the population) that confer not a certainty but rather a risk of disease, typically with odds ratios of 1.2 to 5.0.

But now, in a series of articles in the 15 April 2009 online issue of the *New England Journal of Medicine*, a debate is taking place between proponents of this approach and those who argue that it will never succeed in revealing the genetic basis for complex, polygenic disorders. The reason for this scrutiny is the failure of most of the ongoing studies to find any convincing link with common diseases. It had been expected that the risk of getting cancer, diabetes, and so on would be largely controlled by a relatively small number of common variants, each of which conferred a significant risk, but only a small number of disease-associated variants have been found thus far, and, with a few exceptions, the risk they seem to confer is quite small. As Hardy and Singleton frame the question in one of four papers on the subject, "...discussion has centered on evaluating how far such studies will take us in understanding the risks and causes of disease - and thus the time and resources that should be invested in genotyping more case subjects with any one disease to garner what many see as diminishing genetic returns."

Because they rely on the HapMap, current studies identify loci, not specific genes. Moreover, we currently have haplo-type maps only from single nucleotide polymorphisms (SNPs) present in at least 5% of chromosomes of each of just three groups of defined ancestry: Yoruban, Northern and Western European, and Asian (Chinese and Japanese), so by definition the markers are for rather common variants (present at \> 5% frequency) in the human population. Underlying the project at present, then, is the assumption that common diseases are associated with common variations. A further assumption is that, even if individual alleles have only a small effect on one's risk for a disease, each contribution is large enough that a manageably small number will sum to a significant effect. But what if each contribution is very small?

In a companion perspective, Goldstein argues that very many very small contributions is exactly the case and questions the wisdom of continuing this strategy. He points out that there are examples of its successful application: "For example, when exposed to the anti-HIV drug abacavir, a hypersensitivity reaction develops in more than half the carriers of the HLA-B\*5701 allele, whereas such a reaction occurs in less than 5% of patients without this allele. Similarly, just three common variants are sufficient to explain 14% of the population variation in HIV-1 viral load." But, he continues, "with traits such as height or type 2 diabetes, it seems that an inordinate number of common SNPs would be needed to account for a sizable fraction of heritability... The apparently modest effect of common variation on most human diseases and related traits probably reflects the efficiency of natural selection in prohibiting increases in disease-associated variants in the population." In other words, common diseases might well be caused by many different combinations of a large number - probably hundreds - of very rare variants, which would even eliminate the utility of the SNP hunt in identifying pathways leading to disease. "In pointing at everything," Goldstein writes, "genetics would point at nothing."

Similar concerns are expressed by Kraft and Hunter in a companion piece (although they favor continuing the common variant hunt). "First, the relative risks that are found to be conferred by common risk genotypes account for only a small proportion of the sibling recurrence risk (or the risk that a sibling will also have the disease of interest). Second, in multivariate analyses of large epidemiologic data sets in which a family history of a disease is a risk factor, the inclusion of data regarding which subjects carry the known associated variants only minimally reduces the risk associated with a family history of the disease. Third, in the case of diseases that have been the focus of several genome-wide association studies, some alleles have been detected more than once, but each study has identified multiple alleles that were not identified in other studies, suggesting that many more alleles remain to be discovered. These factors suggest that many, rather than few, variant risk alleles are responsible for the majority of the inherited risk of each common disease."

One truly surprising result from the studies thus far is that the majority of loci identified as associated with disease risk do not map to the coding regions of individual genes. Instead, they possibly affect either the splicing of the messenger RNA or the sequences of microRNAs that regulate gene expression. Deducing the effects of non-coding changes on the level of active protein(s) in the cell is simply not possible from first principles at the moment; it will require huge experimental efforts in multiple laboratories.

So all this really seems very discouraging, but I have a modest proposal for a somewhat altered approach that I think could yield exciting results rapidly. The problem with most fishing expeditions, which is what genome-wide association studies are, is that one is never sure that one is fishing where the fish are. My proposal is to focus on where we know there are fish (or, to use another analogy, to look for the keys under the lamppost because that's where the light is). That seems unlikely to provide new information, but hear me out. I think the mistake we're making is in looking at the association between SNPs, many of which mean little or nothing, and disease. What we should be doing is looking at the association between diseases.

There are literally hundreds of inherited metabolic disorders, most of which are autosomal recessive - they require mutation in both copies of the gene in question to produce the disease. In many cases there are dozens or even more than a hundred known alleles in the gene in question, any two of which suffice. Carriers for these diseases have just a single variant and are usually free from symptoms of the disease. But it is slowly becoming clear that for at least some of the inborn errors of metabolism, the carriers are at altered risk for something else. It may be that a carrier has a reduced risk for an infectious disease, but often I think a problem with a metabolic enzyme will produce haploinsufficiency in some pathway that is involved in a very different disorder. Thus, carriers for the recessive, lysosomal storage disorder Gaucher disease are almost an order of magnitude more likely to develop Parkinson's disease. Is the connection through lysosomal dysfunction? Maybe, and that's testable: it suggests that carriers for other lysosomal storage diseases such as Niemann-Pick, Tay-Sachs, Anderson-Fabray, and Pompe's diseases should also be at increased risk for Parkinson's and perhaps other neurological disorders.

That's exactly the sort of thing a genome-wide association study could determine, and it would shed valuable light on the causes of a class of common diseases. I think it's almost guaranteed to turn up things, because metabolism is tied into all the other pathways in the cell, and because by definition the carrier alleles for a recessive disorder are mutations that must have some definite effect on the expression or function or stability of the protein in question.

In short, I think we should look at rare diseases for less rare genetic loci (the carrier frequency for Gaucher's is estimated to be 1 in 100 in the general population, and around in 1 in 20 among Ashkenazi Jews) that we know have physiological consequences, and ask whether they are associated with the risk for other, more common diseases. I think that's where the interesting connections are most likely to be found, at least until we can sequence lots of whole genomes very cheaply. After all, in a real criminal case, the police usually focus on suspects they know are likely to be guilty, because they have already been proven guilty of other things in the past. That's guilt by association, to be sure, but it tends to work.


abstract: # Background
  .
  Energy drink consumption has continued to gain in popularity since the 1997 debut of Red Bull, the current leader in the energy drink market. Although energy drinks are targeted to young adult consumers, there has been little research regarding energy drink consumption patterns among college students in the United States. The purpose of this study was to determine energy drink consumption patterns among college students, prevalence and frequency of energy drink use for six situations, namely for insufficient sleep, to increase energy (in general), while studying, driving long periods of time, drinking with alcohol while partying, and to treat a hangover, and prevalence of adverse side effects and energy drink use dose effects among college energy drink users.
  .
  # Methods
  .
  Based on the responses from a 32 member college student focus group and a field test, a 19 item survey was used to assess energy drink consumption patterns of 496 randomly surveyed college students attending a state university in the Central Atlantic region of the United States.
  .
  # Results
  .
  Fifty one percent of participants (*n* = 253) reported consuming greater than one energy drink each month in an average month for the current semester (defined as energy drink user). The majority of users consumed energy drinks for insufficient sleep (67%), to increase energy (65%), and to drink with alcohol while partying (54%). The majority of users consumed one energy drink to treat most situations although using three or more was a common practice to drink with alcohol while partying (49%). Weekly jolt and crash episodes were experienced by 29% of users, 22% reported ever having headaches, and 19% heart palpitations from consuming energy drinks. There was a significant dose effect only for jolt and crash episodes.
  .
  # Conclusion
  .
  Using energy drinks is a popular practice among college students for a variety of situations. Although for the majority of situations assessed, users consumed one energy drink with a reported frequency of 1 – 4 days per month, many users consumed three or more when combining with alcohol while partying. Further, side effects from consuming energy drinks are fairly common, and a significant dose effect was found with jolt and crash episodes. Future research should identify if college students recognize the amounts of caffeine that are present in the wide variety of caffeine-containing products that they are consuming, the amounts of caffeine that they are consuming in various situations, and the physical side effects associated with caffeine consumption.
author: Brenda M Malinauskas; Victor G Aeby; Reginald F Overton; Tracy Carpenter-Aeby; Kimberly Barber-Heidal
date: 2007
institute: 1Department of Nutrition and Dietetics, East Carolina University, Greenville, North Carolina, USA; 2Department of Health Education and Promotion, East Carolina University, Greenville, North Carolina, USA; 3Department of Health, Physical Education, Recreation, and Dance, Virginia State University, Petersburg, Virginia, USA; 4School of Social Work, East Carolina University, Greenville, North Carolina, USA
references:
title: A survey of energy drink consumption patterns among college students

# Background

Energy drink consumption has continued to gain popularity since the 1997 debut of Red Bull, the current leader in the energy drink market \[1\]. More than 500 new energy drinks were launched worldwide in 2006 and beverage companies are reaping the financial rewards of the 5.7 billion dollar energy drink industry \[1\]. Energy drinks, including Red Bull, Amp, Monster, Rock Star, Rip It, Full Throttle, and Cocaine, are designed to give the consumer a "jolt" of energy provided by the combination of stimulants and "energy boosters" that they provide, including caffeine, herbal extracts such as guarana, ginseng, and ginkgo biloba, B vitamins, amino acids such as taurine, amino acid derivatives such as carnitine, and sugar derivatives, including glucuronalactone and ribose \[1\]. Energy drinks typically contain 80 to 141 mg of caffeine per 8 ounces, the equivalent of five ounces of coffee or two 12-ounce cans of caffeinated soft drink such as Mountain Dew, Coca Cola, Pepsi Cola or Dr. Pepper \[2\]. Energy drinks have sugar-containing and sugar-free versions. For example, Monster Energy provides 24 grams of sugar per 8 ounces (12% sugar concentration) and Rip It A'Tomic Pom provides 33 grams (14% concentration) \[3,4\]. Similar to the booming energy drink market, the size of the energy drink container has increased over 300-fold; Monster energy offers consumers a 23 ounces option \[3\].

Do energy drinks provide the consumer an extra burst of energy as the advertisements would have you believe? Yes, they do. Smit and colleagues found that energy drinks, as compared to placebo, had energizing effects among 18 to 55 year old participants, with effects being strongest 30 to 60 minutes after consumption and sustained at least 90 minutes \[5\]. Caffeine was found to be the primary constituent responsible for these effects. Although there is no human requirement for caffeine, even low doses of caffeine (12.5 to 100 mg) improve cognitive performance and mood \[6\]. However, caffeine has been found to have detrimental health consequences. Riesenhuber and colleagues found that the caffeine (but not taurine) in energy drinks promotes diuresis and natriuresis \[7\]. Further, acute caffeine consumption reduces insulin sensitivity \[8\] and increases mean arterial blood pressure \[9\]. High caffeine consumption is associated with chronic daily headaches, particularly among young women (age \< 40 years) and among those with chronic episodic headaches and of recent onset (\< 2 years) \[10\]. Central nervous system, cardiovascular, gastrointestinal, and renal dysfunction have been associated with chronic caffeine ingestion \[11\]. In sum, the caffeine in energy drinks will provide the consumer the desirable effects of increased alertness, improved memory, and enhanced mood. However, caffeine can have harmful physical consequences.

Although energy drinks are targeted to the 18 to 35 year old consumer \[12\], there has been little research regarding energy drink consumption patterns among young adults in the United States. The purpose of this study was to determine (1) energy drink consumption patterns among college students, (2) prevalence and frequency of energy drink use for six situations, namely for insufficient sleep, to increase energy (in general), while studying, driving long periods of time, drinking with alcohol while partying, and to treat a hangover, (3) and prevalence of adverse side effects and energy drink use dose effects among college energy drink users.

# Methods

A Registered Dietitian and a Health Educator designed a questionnaire that assessed consumption patterns of energy drinks among college students. We initially interviewed a focus group of 32 college students who were enrolled in a senior-level course. We asked these students open-ended questions regarding situations in which college students use energy drinks, the most common energy drinks college students were using, frequency patterns (average number of energy drinks consumed for each situation the focus group identified and the average number of times per month throughout a semester students use energy drinks for each situation), and side effects from using energy drinks.

Based on the focus group responses we developed a 19-item questionnaire. Questions 1 and 2 assessed demographic information (age and sex). Question 3 was a screening question, used to identify energy drink users, and asked "in an average month for the current semester do you drink more than one energy drink per month?" If a participant indicated "no", then they were instructed to skip the remaining questions in the survey and return the questionnaire to the research assistant. Participants who indicated "yes" to Question 3 were instructed to continue the survey, which assessed the type of energy drink usually consumed (regular or sugar-free), side effects associated with energy drink use (jolt and crash episodes, headaches, heart palpitations), and six situations for energy drink use (insufficient sleep, needing more energy (in general), studying for an exam or to complete a major course project, driving a car for a long time, drinking with alcohol while partying, and to treat a hangover).

For the purpose of this study, a jolt and crash episode was in reference to a feeling of increased alertness and energy (the jolt) followed by a sudden drop in energy (the crash) that occurs in response to using energy drinks.

Each of the six situation questions had two follow up questions that assessed the average number of energy drinks consumed for that situation (for example, how many energy drinks do you drink at one time following a night of not getting enough sleep?) and the average number of times per month for the current semester the student consumes energy drinks for that situation.

To provide a frame of reference regarding what constituted an energy drink, the introduction of the questionnaire included examples of energy drinks that were popular on the campus and in social establishments in the immediate geographic region when the survey was administered, these included Red Bull, Rock Star, Amp, and Full Throttle. The questionnaire was field tested among 10 randomly chosen students who were in a public location on campus. The questionnaire took approximately two minutes to complete and modifications to the questionnaire were not necessary based on the field test responses.

From mid-November to the first week of December 2006, 11 trained research assistants (undergraduate and graduate college students) recruited students at a single college from public locations across campus to participate in the study. The research assistants first ensured that those they approached were students at the university and that the student had not previously completed the questionnaire.

The institution is a state university, located in the Central Atlantic region of the United States. The fall 2006 enrollment statistics indicate an undergraduate enrollment of approximately 18,000 undergraduate and 6,000 graduate students, 85% of undergraduates were 18 to 24 years of age, 12% were 25 to 40 years of age and 3% 41 years of age and older \[13\]. Further, 92% of undergraduates attended school full-time whereas the majority (60%) of graduate students attended part time. In regard to ethnicity of the student body, 76% were non-Hispanic White, 16% non-Hispanic Black, 2% Asian, 2% Hispanic, 2% unknown, \< 1% American Indian, and \< 1% non-resident alien.. Sixty two percent of the total student body is female \[13\].

To diversify our sample, research assistants varied the time of day and days of the week during weekdays to recruit participants. In compliance with the university's Institutional Review Board for Research with Human Subjects (University and Medical Center Institutional Review Board number 06-0718), students were informed of the study protocol and those willing to participate anonymously completed the self-administered questionnaire. The project was carried out in compliance with the Helsinki Declaration.

Analyses were performed using JMP IN^®^ software \[14\]. Descriptive statistics included means, standard deviations, 95% confidence intervals, and frequency distributions. Pearson *χ*^2^ was used to evaluate differences in frequency distribution of responses. An alpha level of .05 was used for all statistical tests.

# Results

A total of 496 participants, aged 21.5 ± 3.7 years (95% *CI* 21.3, 21.8) completed the questionnaire. In regard to the first research question, energy drink consumption patterns among college students, 51% of participants (*n* = 253) reported drinking greater than one energy drink each month in an average month for the current semester, with significantly more female (53%) than male (42%) energy drink users reported, χ^2^ (1, *N* = 496) = 6.46, *p* = .01. Seventy four percent (*n* = 187) of the 253 users drank sugar-containing versions with significantly more females (35%) than males (12%) drinking sugar-free versions, χ^2^ (1, *N* = 247) = 16.56, *p* \< .01.

Energy drink consumption patterns of college energy drink users for the six situations assessed are reported in Table 1. Insufficient sleep was the most common reason to drink energy drinks, as indicated by 67% of energy drink users. The majority of users consumed energy drinks to increase their energy (65%) and to drink with alcohol while partying (54%). Fifty percent drank while studying or completing a major course project, 45% while driving a car for a long period of time, and 17% to treat a hangover. There were no significant differences in use of energy drinks for the six situations assessed by sex, as reported in Table 1.

Situations of energy drink use among college energy drink users in an average month for the current semester

| Situation | % of females | % of males | χ^2^ | *p* (sex) |
|----|----|----|----|----|
| Insufficient sleep^a^ | 67 | 68 | 0.17 | .68 |
| Need energy (in general)^a^ | 62 | 69 | 1.27 | .26 |
| Studying or major project^b^ | 46 | 56 | 2.22 | .14 |
| Driving car for long period of time^a^ | 40 | 51 | 3.01 | .08 |
| Mix with alcohol while partying^a^ | 57 | 50 | 1.33 | .25 |
| Treat hangover^a^ | 16 | 18 | 0.18 | .67 |

^a^*n* = 146 females, 107 males, χ^2^ (1, *N* = 253); ^b^*n* = 145 females, 104 males, χ^2^ (1, *N* = 249).

In regard to the second research question, the percent of users drinking one, two, and three or more energy drinks by situation are reported in Table 2. The majority of energy drink users consumed one to treat a hangover, for insufficient sleep, to increase energy, and while driving a car for a long period of time. Using three or more was a common practice (49% of users) to drink with alcohol while partying. The percent of users drinking energy drinks 1 – 4, 5 – 10, and 11 or more days in an average month for the current semester are also reported in Table 2. For the six situations assessed, the majority of users (73% to 86%) consumed energy drinks 1 – 4 days in a month.

% of college energy drink users^a^ reporting amount and frequency of energy drink consumption by situation in an average month for the current semester

|  |  | Energy drinks consumed |  |  | Days per month |  |  |
|----|----|----|----|----|----|----|----|
|  |  |  |  |  |  |  |  |
| Situation | *n* | 1 | 2 | ≥3 | 1 – 4 | 5 – 10 | ≥11 |
| Insufficient sleep | 169 | 64 | 22 | 14 | 74 | 18 | 8 |
| Need energy (in general) | 165 | 63 | 21 | 16 | 74 | 18 | 8 |
| Studying or major project | 125 | 50 | 36 | 14 | 85 | 10 | 5 |
| Driving car for long period of time | 114 | 63 | 23 | 14 | 86 | 9 | 5 |
| Mix with alcohol while partying | 136 | 27 | 24 | 49 | 73 | 18 | 9 |
| Treat hangover | 42 | 74 | 10 | 16 | 74 | 14 | 12 |

^a^*n =* 253 college energy drink users.

To further identify relationships between the six situations of energy drink use and energy drink consumption patterns, we summed the number of situations for reported energy drink use and compared this to the maximum number of energy drinks consumed for any of the six situations. These results are reported in Table 3. By sum of situation categories, 16% to 20% of energy drink users consumed energy drinks for a total of one to five of the six situations, 7% consumed energy drinks for a total of all six. As total situations increased so did the maximum energy drink consumption for at least one situation. For example, 40% to 81% of energy drink users who reported a total of three or more situations consumed three or more energy drinks for at least one situation, whereas 29% of those with a total of one situation and 18% of those with a total of two consumed three or more for at least one situation.

Maximum number of energy drinks consumed for any of six situations by sum of situations^a^ in an average month for the current semester among college energy drink users

|  |  | Maximum energy drink intake for any situation |  |  |
|----|----|----|----|----|
|  |  |  |  |  |
| Parameter | *n* | 1 | 2 | ≥3 |
| % of 1 situation responders | 45 | 56 | 15 | 29 |
| % of 2 situation responders | 38 | 55 | 27 | 18 |
| % of 3 situation responders | 45 | 33 | 27 | 40 |
| % of 4 situation responders | 46 | 20 | 37 | 43 |
| % of 5 situation responders | 43 | 5 | 32 | 63 |
| % of 6 situation responders | 16 | 6 | 13 | 81 |

Note: χ^2^ (10, *N* = 233) = 53.43, *p* \< .01.

^a^Sum of six situations reported energy drink use.

Regarding the third research question, weekly jolt and crash episodes were experienced by 29% of users, 22% reported ever having headaches and 19% heart palpitations from consuming energy drinks, which did not differ significantly by sex, χ^2^ (1, *N* = 253) \< 0.01, *p* = .97 for jolt and crash episodes, χ^2^ (1, *N* = 234) = 0.37, *p* = .54 for heart palpitations, χ^2^ (1, *N* = 252) = 0.45, *p* = .50 for headaches. The data for side effects by energy drinks consumed are reported in Table 4. There was a significant dose effect for jolt and crash episodes but not for heart palpitations or headaches. For example, 57% of energy drink users who reported experiencing weekly jolt and crash episodes also consumed three or more energy drinks for at least one situation, whereas 35% of those who denied jolt and crash episodes consumed three or more.

Side effects by maximum number of energy drinks consumed for any of six situations in an average month for the current semester among college energy drink users

|  |  | Maximum energy drink intake |  |  |  |  |
|----|----|----|----|----|----|----|
| Parameter | *n* | 1 | 2 | ≥3 | χ^2^ | *P* (yes versus no) |
| Weekly jolt and crash episodes | 253 |  |  |  | 19.10 | \< .01 |
|  % of yes responders | 74 | 12 | 31 | 57 |  |  |
|  % of no responders | 159 | 40 | 25 | 35 |  |  |
| Ever having heart palpitations | 215 |  |  |  | 4.77 | .09 |
|  % of yes responders | 40 | 20 | 22 | 58 |  |  |
|  % of no responders | 175 | 34 | 27 | 39 |  |  |
| Ever having headaches | 232 |  |  |  | 1.24 | .54 |
|  % of yes responders | 51 | 27 | 24 | 49 |  |  |
|  % of no responders | 181 | 33 | 27 | 40 |  |  |

# Discussion

Energy drinks are marketed to young adults and marketing efforts may be particularly appealing among college students. For example, Cocaine energy drink, with a Cut Cocaine variety, has been marketed as a "legal alternative" to the class A drug \[15\]. On April 4, 2007, the Food and Drug Administration issued a warning to Drink Reboot, the firm that markets Cocaine, citing numerous marketing violations, including promoting this product as a street drug alternative \[15\]. Red Bull energy drink is reportedly a "functional beverage" that was designed to increase physical and mental performance and "is appropriate to drink during sports, while driving, and during leisure activities" \[16\] whereas Monster energy provides a "double shot of our killer energy brew. It's a wicked mega hit that delivers twice the buzz of a regular energy drink..." \[3\]. The purpose of this study was to identify energy drink consumption patterns and side effects associated with consumption of energy drinks among college students. We found that energy drink consumption is a popular practice among college students, particularly if the student has had insufficient sleep, if they need more energy in general, while studying for exams or working on major course projects and while driving an automobile for a long period of time.

Improvements in mental functioning are of interest among college students, many who suffer from sleep deprivation. The American College Health Association reported that 71% of college students whom they surveyed reported insufficient sleep and not feeling rested for at least five of the past seven days \[17\]. Sleep deprivation is associated with selecting less difficult cognitive tasks and college students who have sleep difficulties report a greater frequency of stress \[18,19\]. Findings from our study support the premise that college students use energy drinks to treat sleep deprivation and while studying for exams or completing major course projects. On the other hand, caffeine consumption has not been found to affect academic performance among college students \[20\].

The primary ingredient in energy drinks that has a cognitive stimulating effect is the caffeine \[5\], whereas high sugar content (18% concentration) does not improve reaction times slowed by sleep deprivation \[21\]. Further, the combination of caffeine and taurine has no effect on short-term memory \[9\]. Although low doses of caffeine (12.5 to 50 mg) have been found to improve cognitive performance and mood \[6\] and 200 mg doses have been found to improve cognitive task speed and accuracy and increase alertness among young adults \[22\], the amount of caffeine provided in energy drinks can easily far exceed the amount necessary to promote cognitive functioning \[23\]. This is especially true if a student is consuming 16- or 23-ounce cans or multiple cans of energy drinks for a given situation. Although we did not assess the size of the energy drink cans that participants normally consumed, results from our study indicate that in some situations while students are consuming energy drinks, the amount of caffeine that they consume can exceed the amount needed simply to promote cognitive stimulation. For example, 50% of energy drink users in our study drank two or more energy drinks while studying for an exam or working on a major course project, and 36% to 37% drank two or more following insufficient sleep, when they needed energy throughout the day, or while driving an automobile for a long period of time. Further, drinking multiple energy drinks with alcohol was a popular practice among 73% of energy drink users. The practice of consuming greater amounts of caffeine while socializing has also been documented among American youth \[24\] and an alcoholic setting is considered by many college students a primary locus to socialize and to meet people \[25\].

Results from the present study indicate that female and male college students are using energy drinks in a similar fashion. Whereas we found a greater prevalence of energy drink consumption and greater use of sugar-free varieties of energy drink use among females, we identified no situation differences nor prevalence of side effects from consuming energy drinks between sexes.

There are a number of limitations to this study that deserve discussion. First, in an effort to ensure the survey instrument could be completed quickly, we collected limited demographic information. Based on the descriptive statistics regarding age, we primarily had undergraduate participants and a slightly greater percentage of male participants as compared to the sex distribution at the university. On the other hand, random sampling throughout the weekdays and times of the day at central locations throughout campus was an advantage to the study design. Additionally, this is a rural state university with a fairly homogenous student body. Second, the data collected was self-reported. In particular, frequency patterns of energy drink intake were asked by situation and were treated as independent and distinct events, which may not have been the case. For example, and energy drink user may consume energy drinks because they had not gotten enough sleep and because they were studying for an exam. As a result, assessment of energy drink consumption may have been overestimated for each of the situation events. On the other hand, the results from this study provide important and novel information regarding energy drink consumption habits among college students. Of particular importance is the finding that using energy drinks for a number of situations is common among college students and that those who use energy drinks for three or more of the situations that we assessed tended to drink three or more energy drinks for at least one situation. Further, side effects of jolt and crash episodes, heart palpitations, and headaches are fairly common, as reported by approximately 25% of users, and there is a significant dose effect of energy drink consumption and jolt and crash episodes.

# Conclusion

Using energy drinks is a popular practice among college students, as we found that 51% of 496 college students surveyed reported drinking greater than one energy drink each month. Among college energy drink users, consuming energy drinks is particularly popular for insufficient sleep, when one needs more energy in general, to drink with alcohol while partying, and when studying for an exam or completing a major course project. Drinking three or more for a given situation occurs more frequently among those who consume energy drinks for three or more of the six situations that were assessed. Side effects of consuming energy drinks, including experiencing jolt and crash episodes, hear palpitations, and headaches occur in many energy drink users. However, a dose effect was found only for jolt and crash episodes. Further research should identify if students recognize the amounts of caffeine that are present in the wide variety of caffeine-containing products they consume, the amounts of caffeine that are consumed in various situations, and the physical side effects associated with caffeine consumption.

# Competing interests

The author(s) declare that they have no competing interests.

# Authors' contributions

BMM participated in the study design, performed the statistical analysis, and drafted the manuscript. VGA conceived of the study and drafted the manuscript. AJC assisted with statistical analysis and helped to draft the manuscript. RFO, TCA, and KBH participated in coordination and data collection and helped to draft the manuscript. All authors read and approved the final manuscript.


abstract: # Background
  .
  A nutritional assessment method that is quick and easy to conduct would be extremely useful in a complex emergency, where currently there is no agreed practical and acceptable method. Hair pluckability has been suggested to be a useful method of assessing protein nutritional status. The aim was to investigate the reliability of the trichotillometer and to explore the effects of patient characteristics on hair epilation force.
  .
  # Methods
  .
  Three observers plucked hair from twelve participants to investigate the within- and between-observer reliability. To investigate the effect of patient characteristics on hair pluckability, 12 black African and 12 white volunteers were recruited. Participants completed a short questionnaire to provide basic information on their characteristics and hair.
  .
  # Results
  .
  Mean hair pluckability measurements for the 12 participants obtained by the three observers (39.5 g, 41.2 g and 32.7 g) were significantly different (p \< 0.001). Significant variation between patients was also found (p \< 0.001). None of the patient characteristics significantly affected hair pluckability, with the exception of age, although this relationship was not consistent.
  .
  # Conclusion
  .
  Due to significant variation in measurements, hair pluckability does not appear to be a reliable method for assessing adult nutritional status. Hair pluckability could be a useful method of nutritional assessment in complex humanitarian emergencies but only if the reliability was improved.
author: Laura A Wyness; Geraldine McNeill; Gordon J Prescott
date: 2007
institute: 1Department of Public Health, University of Aberdeen, Medical School, Foresterhill, Aberdeen AB25 2ZD, UK; 2Department of Environmental and Occupational Medicine, Liberty Safe Work Research Centre, Foresterhill Road, Aberdeen AB25 2ZP, UK
references:
title: Trichotillometry: the reliability and practicality of hair pluckability as a method of nutritional assessment

# Background

Complex emergencies are usually characterised by large numbers of displaced persons and overwhelming need for shelter, water, sanitation and health care commonly due to extreme insecurity. Time and resources available during a complex emergency are often extremely limited, so a nutritional assessment method that is quick and easy to conduct is required. Mid-upper arm circumference and weight can be (and are) used in complex emergencies, although there remains some debate regarding the appropriate cut-off measurements to indicate nutritional status.

One of the signs of protein-energy malnutrition is hair that can be plucked easily \[1\]. Protein is the main component of hair; forming between 65 to 95% of the hair by weight \[2\]. During protein deficiency, blood proteins are maintained at the expense of structural protein; therefore structural proteins are an earlier indicator of protein insufficiency \[3\]. The hair root shows a prompt response to protein deficiency. Studies have shown that crash dieting, where the diet is severely constrained over a short period, can precipitate hair loss \[4,5\]. Chronic starvation, especially marasmus, is also associated with diffuse hair loss \[6\] and hair that is easy to pluck \[7,8\]. Chase *et al*. (1981) found patients with kwashiorkor or marasmic kwashiorkor had slightly decreased epilation force than patients with "pure" marasmus \[9\]. This should be borne in mind when assessing malnourished individuals. Further investigation of this issue was beyond the scope of this paper. In complex emergencies inexpensive and simple methods for screening for malnutrition and for assessing changes in nutritional status are required.

Two studies of measurement of hair pluckability as a possible measure of nutritional status have been reported \[9,10\]. In these studies, a hand-held spring dynamometer, or "trichotillometer" was used to measure the force in grams that was required to pluck individual hairs from the scalp. Chase *et al*. (1981) \[9\] measured the hair epilation force of 17 malnourished and 16 well-nourished hospitalized patients using the trichotillometer. Epilation force was found to be significantly correlated with weight, triceps skinfold thickness, arm muscle circumference and some laboratory assessments of nutritional status. Smelser *et al*. (1982) \[10\] determined the usefulness of trichotillometry under field conditions by measuring hair epilation force of 69 subjects at a hospital in Nigeria. Epilation force was found to be significantly correlated with weight-for-height, serum albumin and mid arm muscle circumference. The studies \[9,10\] both concluded that the trichotillometer might be a useful method for assessing protein nutritional status. However, to be useful in the field the method needs to have low within- and between-observer variation and low intra-individual variation. The present study was therefore conducted to investigate the reliability of hair pluckability as measured by a trichotillometer.

# Methods

## Study subjects

Data was collected for the survey investigating the reliability of the trichotillometer from staff and students at the University of Aberdeen. The inclusion criteria for the study were that participants were aged 18 years or over at the time of the study, and that they had hair of adequate length to be plucked, which covered the area on the top of the scalp.

Data was also collected for the comparison survey investigating the effect of participant characteristics on the epilation force required to pluck hair. The initial inclusion criteria for this study were identical to the reliability study described above. Recruitment of black African volunteers was conducted first. White volunteers were then recruited among staff and students at the University of Aberdeen and chosen to balance the black African participants according to gender and age within two years.

Sample size calculations for both proposed studies were performed using the statistical program "nQuery Advisor" (version 4.0), using data from two previous studies \[9,10\], to determine the required number of participants to detect a difference of 1 standard deviation (SD) assuming a power of 80%. These studies found differences in means of 21.2 g and 10.8 g between malnourished and control subjects (with SD of between 9.5 g and 11.8 g) at the 5% level of significance using unpaired t-tests \[9,10\]. Measurements from ten individuals were required to test the within-observer reliability and three observers were required to test the between-observer reliability. Ethical approval was obtained from Grampian Research Ethics Committee for both studies.

## Data collection and measurement technique

All participants completed a short questionnaire to provide basic information on gender, age and ethnicity. Data were also collected about the colour and length of each participant's hair, and whether the hair was currently dyed, permed or if any styling products were applied on the day hair pluckability measurements were collected.

Instructions from the developer of the trichotillometer, Prof. C.L. Krumdieck, were provided and adhered to by the observers. The trichotillometer has an arbitrary scale (units) which can be converted to grams using a calibrated scale. In this study one unit was equivalent to 2.5 g.

In both studies ten hairs from the top of each participant's head were epilated individually. Measurements typically took five minutes for ten hairs. The number of broken hairs and the number of malfunctions of the ratchet mechanism of the trichotillometer were recorded. If required additional hairs were epilated until a sample of ten hairs was achieved. Measurements obtained by three observers were used to assess the between-observer reliability. Measurements obtained from each observer were used to assess within-observer reliability.

## Statistical analysis

Analysis of the data was conducted using SPSS, version 13. A two-way ANOVA was used to investigate the variation in hair pluckability due to differences between observers and between participants. Comparisons between the measurements obtained in groups with different participant characteristics were made using the independent t-test, a one-way ANOVA or Kruskal-Wallis test as appropriate.

# Results

Of the 12 participants included in the reliability study seven were female. Seven were of white British ethnicity and five were of white, non-British ethnicity. One participant did not report her age. The mean age of the other 11 participants was 35.3 years (SD = 9.1 years). The measurements within an individual were generally normally distributed although the distributions were slightly skewed for some individuals.

## Observer variation

The differences in measurement between the three observers can be seen in Figure 1. The mean (SD) hair pluckability measurements for observer 1, 39.5 g (10.9 g), and 2, 41.4 g (13.4 g), were similar, whereas observer 3 obtained a significantly lower mean hair pluckability, 32.7 g (10.0 g). For observers 1, 2 and 3, the average ranges of individual hair pluckability measures and mean coefficients of variation (CV) were 30.5 g, 32.5 g and 28.0 g and 23.7%, 25.8% and 25.4%, respectively.

## Participant variation

Large differences in hair pluckability measurements across the 12 participants were observed (Figure 2). Some participants had similar measurements for all 10 hairs plucked.

## Two-way analysis

A two-way ANOVA was carried out to investigate the variation in hair pluckability due to observer and participant effects. While there were some individuals with skewed measurements, the residuals from this analysis were normally distributed satisfying the relevant assumptions. Variances were homogeneous in the model with an interaction effect. Significant differences in hair pluckability between observers (p \< 0.001) and between participants (p \< 0.001) were found as well as a significant interaction effect (p = 0.001). This indicated that the differences between individuals in terms of hair pluckability were not independent of the observer.

The effect size for the observers (partial eta squared = 0.282) and the participants (partial eta squared = 0.141) can be classified as large using Cohen's 1988 criterion \[11\]. Post-hoc comparisons using the Sheffe's test indicated that the mean hair pluckability for observer 3 was significantly lower than the mean obtained by observers 1 and 2 (p \< 0.001). Observers 1 and 2 did not differ significantly (p = 0.261).

## Comparative study

The basic characteristics of the participants included in the comparative study and the results of the statistical analysis on the data are shown in Table 1. Hair pluckability was not significantly correlated with age. However, when participants were grouped into three age groups, a post hoc comparison using Sheffe's test indicated that the mean pluckability for the age group 30–40 years was significantly lower than the mean score for the age groups 19–29 years and 41–52 years. Therefore, there was no consistent relationship between hair pluckability and age in these data.

Comparative study sample characteristics

| Participant characteristic | Black African n = 12 | White n = 12 | Hair pluckability Mean (SD) | Test statistic (P value) |
|----|----|----|----|----|
| Ethnicity (number): |  |  |  |  |
|  Black African | 12 | 0 | 39.9 (10.8) | 0.89 (0.372)^1^ |
|  White Australian | 0 | 1 | 38.7 (11.0) |  |
|  White British | 0 | 9 | 38.7 (11.0) |  |
|  White German | 0 | 1 | 38.7 (11.0) |  |
|  White Italian | 0 | 1 | 38.7 (11.0) |  |
| Gender (number) |  |  |  |  |
|  Male | 4 | 4 | 40.9 (11.2) | 1.58 (0.115)^1^ |
|  Female | 8 | 8 | 38.5 (10.7) |  |
| Age (Mean (SD)) | 35.3 (9.1)^2^ | 36.7 (9.1) | 36.0 (9.1) | 0.083 (0.208)^3^ |
| Age groups |  |  |  |  |
|  19–29 y | 4 | 2 | 41.6 (12.5) | 10.38 (\<0.001)^4^ |
|  30–40 y | 3 | 6 | 35.4 (9.5) |  |
|  41–52 y | 4 | 4 | 41.7 (10.0) |  |
| Age groups |  |  |  |  |
|  19–36 y | 6 | 6 | 38.4 (11.6) | 1.39 (0.187)^1^ |
|  \>36 y | 5 | 6 | 40.2 (10.1) |  |
| Hair color (number): |  |  |  |  |
|  Black | 11 | 1 | 39.7 (10.9) | 0.157 (0.525)^5^ |
|  Brown | 0 | 8 | 38.9 (10.9) |  |
|  Blonde | 0 | 2 | 38.9 (10.9) |  |
|  Grey | 1 | 0 | 38.9 (10.9) |  |
|  Red | 0 | 1 | 38.9 (10.9) |  |
| Hair length (number): |  |  |  |  |
|  Shorter than ear length | 8 | 8 | 37.5 (32.5, 45.0)^6^ | 1.09 (0.579)^5^ |
|  Between chin and shoulder | 3 | 2 | 37.8 (29.9, 47.5)^6^ |  |
|  Longer than shoulder | 1 | 2 | 42.6 (29.7, 50.1)^6^ |  |
| Hair currently permed |  |  |  |  |
|  Yes | 7 | 0 | 40.2 (10.2) | 0.78 (0.436)^1^ |
|  No | 4 | 12 | 38.9 (11.2) |  |
| Hair currently dyed |  |  |  |  |
|  Yes | 2 | 7 | 41.4 (10.5) | 1.90 (0.058)^1^ |
|  No | 10 | 4 | 38.4 (11.0) |  |
| Currently have hair products on hair |  |  |  |  |
|  Yes | 7 | 6 | 39.5 (10.9) | 0.25 (0.804)^1^ |
|  No | 4 | 6 | 39.1 (11.0) |  |
| Broken hair |  |  |  |  |
|  ≥1 | 3 | 1 | 41.4 (10.7) | -1.36 (0.177)^1^ |
|  None | 9 | 11 | 38.9 (10.9) |  |

^1^Independent t-test, ^2^N = 11 as one participant did not report their age, ^3^Spearman's correlation, ^4^One-way ANOVA, ^5^Kruskal Wallis test, ^6^Median (Interquartile range)

# Discussion

The trichotillometer was previously reported to be a good method for assessing nutritional status in adults \[9,10\]. Although the effect of acute stress on hair pluckability using the trichotillometer \[9\] and the usefulness of the trichotillometer under field conditions \[10\] have been previously investigated, the reliability and the effect of various individuals' characteristics on hair pluckability have not been investigated. The observations presented here are consistent with Chase *et al*. \[9\] who found the average observed mean hair pluckability (SD) among well-nourished patients, when plucking ten individual hairs was 36.0 g (12.4 g).

Variation between observers is not desirable since similar measurements should be obtained by all observers who use the same instrument on the same individual. This study found two of the observers reported similar results and one reported significantly lower measurements by, on average 8.7 g, which in clinical terms is quite a large difference. It is possible that a variation of this magnitude would effect the classification of the nutritional status of an individual.

Variation within observers is also not desirable and, from a clinical perspective, this mean variation of close to 30 g within an observer is large. This wide variation in individual hair pluckability measurements indicates that an adequate amount of individual hairs need to be plucked in order to obtain a reproducible and representative mean hair pluckability measurement.

Variation between participants for reasons unrelated to nutritional status would not be a welcome finding, as this could obscure differences between individuals with different nutritional status. This study found significant differences between the participant's hair pluckability measurements. There was also wide variation in the ten measurements obtained for each participant as indicated by relatively large coefficient of variation (CV). A CV of \>30% is often considered as large experimental variability \[12\]. This may be due to biological variation in hair pluckability as the force required to pluck hair is likely to vary throughout the different stages of growth. A balance between the time available and the number of hairs required to be plucked in order to obtain a valid measurement needs to be found.

A significant interaction effect was found, indicating that the differences between individuals in terms of hair pluckability were not independent of the observer. This is not desirable since the tool should be able to discriminate between individuals regardless of the observer.

No significant difference in hair pluckability between black African and white adults or between males and females was found. However, since the number of male participants was small (n = 8), a larger study may be required to ensure the results are generalisable to a wider population. There was no consistent relationship between hair pluckability and age. One result suggested that younger and older age groups required a larger force to pluck hair than the middle age group of 30–40 year olds. A larger study would be required to verify this finding due to the relatively small number of participants in this study. No significant difference in hair pluckability was identified with hair colour or length, even when the categories were combined to increase the number of participants in the smaller groups.

All three observers were given the same instructions on how to use the trichotillometer, and were allowed to practice obtaining measurements until they felt confident using it. Due to the availability of the observers and participants, observers may have taken measurements on a participant on different days. However, all measurements were obtained from all three observers within three days of each other. This may be a source of variation as the participant may have used hair products for one measurement and not another. However, it is unlikely to have had an effect as no significant association was found between hair pluckability and the use of hair products. Although none of the participants in this study objected to having ten hairs pulled out, the acceptability to some individuals may be lower, for example due to a lower pain threshold or traditional beliefs not permitting the removal of hair, as in some African cultures.

# Conclusion

In conclusion, one classification scale can be used when assessing hair pluckability for all adults as no significant differences were identified with any of characteristics of the participants. However, the differences found between the measurements obtained by each observer and wide variations in measurements within observers suggest that the trichotillometer is not a reliable method for assessing adult nutritional status. If the reliability of the trichotillometer could be improved, for example, by adjusting the design, hair pluckability would be an extremely useful method of nutritional assessment during a complex emergency, or a situation where savings on time and resources need to be made.

# Competing interests

The author(s) declare that they have no competing interests.

# Authors' contributions

LAW collected and analysed the data and wrote the manuscript. GM provided advice on the study design and collection of the data, and critically revised the manuscript. GJP provided advice on the collection and analysis of the data, and critically revised the manuscript. All authors read and approved the final manuscript.

### Acknowledgements

The authors would like to thank Professor Carlos L Krumdieck for supplying the trichotillometer and Shona Fielding, and Kirsten Harrild from the University of Aberdeen, for assisting with the data collection. Thanks are also due to the participants who volunteered from "The Aberdeen African Women's Group", the "Fountain of Love" church, and the University of Aberdeen.