Brooke Allen and Professor Beverly Roeder, Biology
Eating disorders (EDs) are a group of mental illnesses that afflict up to two percent of the population . The group of illnesses consists of anorexia, bulimia, and EDNOS (Eating Disorders Not Otherwise Specified). The diagnostic methods for eating disorders that are currently accepted by the American Psychiatric Association are problematic, because they rely mainly upon patient responses to self-report or physician-administered examinations. These assessments do not always return accurate diagnoses, because they are primarily subjective in nature . Thus, a more objective method for diagnosis, one which is more focused on physiological measures than on subjective questions, is needed for the successful diagnosis and treatment of eating disorders.
The primary demographic that suffers from EDs is young women, and those exhibiting high levels of exercise have an increased likelihood of developing these disorders , . Interestingly, athletic females are also some of the most difficult individuals in whom to diagnose eating disorders. Indeed, it is difficult to assess criteria such as binge eating and excessive exercise in athletes, because of their above-average caloric intake and exercise levels. Therefore, an effective ED diagnostic method should be able to objectively diagnose eating disorders in non-athletes and athletes alike.
The purpose of this study was to determine whether one recently developed physiological method of ED diagnosis, which employs the analysis of stable isotope ratios of head hairs, would be useful for ED diagnosis in athletes. This diagnostic method has already shown preliminary success when used with non-athlete individuals with eating disorders . We believed that the nature of this particular method would allow it to return high levels of sensitivity and specificity in the diagnosis of EDs in athletes, comparable to those levels that had been achieved with non-athletes, despite the differences in eating and exercise patterns of athletes relative to non-athletes.
During 2008, we collected head hair samples from female athletes on the BYU track and cross-country teams, and from non-athlete female students from BYU classes. We also administered a written diagnostic questionnaire to the individuals from whom we collected the hair samples. We labeled with identification numbers the hair samples that we collected, and the identification numbers will be linked back to the results of the questionnaires after discriminant analysis of the stable isotope ratios is complete. The results of the written assessments will be used as standards in determining the accuracy of the diagnoses reached through stable isotope analysis.
During 2009, we have been working on preparing the hair samples for analysis by the mass spectrometer. The first step in preparing the samples is to clean them. We enclosed each sample in filter paper and sonicated them in water for 30 minutes, and then in petroleum ether for 30 minutes. The samples were allowed to dry overnight after each of these steps. Once the samples were cleaned and dried, we aligned the proximal ends of all of the hairs (about 5 hairs were collected from each individual, and all of the hairs from each individual were prepared and analyzed together). Beginning at the distal end, we cut the hairs into small sections, placing each section in its own small tin capsule. Each tin capsule was weighed and then placed into the mass spectrometer tray. The trays were labeled with the individual’s identification number and with the proximity of the specific sample to the root of the hair. We are currently finishing this part of the procedure, after which the samples will be run through the mass spectrometer. The majority of my ORCA grant funds will be used to pay for running the mass spectrometer.
After the samples are run through the mass spectrometer, we will use discriminant analysis of the carbon and nitrogen ratios of the hair samples to attempt to diagnose each individual as healthy, anorexic, or bulimic. When I have the results prepared, I will be able to complete the manuscript I have been working on for the past several months. I plan to submit my manuscript for publication before I graduate in December. I am confident that this project will result in a publication in a scholarly journal, and hopeful that it will result in important findings for the future of eating disorder diagnosis and management.
References
- National Institutes of Health, Substance Abuse and Mental Health Services Administration. (2000). Mental Health and Mental Disorders. Healthy People 2010. http://www.hhs.gov/pharmacy/phpharm/hpmental.html.
- Hatch et al. (2006). An objective means of diagnosing anorexia nervosa and bulimia nervosa using 15N/14N and 13C/12C ratios in hair. Rapid Communications in Mass Spectrometry 20: 3367-3373.
- National Institutes of Health, Substance Abuse and Mental Health Services Administration. (2000). Mental Health and Mental Disorders. Healthy People 2010. http://www.hhs.gov/pharmacy/phpharm/hpmental.html.
- Peden et al. (2008). The Effects of External Pressures and Competitiveness on Characteristics of Eating Disorders and Body Dissatisfaction. Journal of Sport and Social Issues 32: 415-430.
- Hatch et al. (2006). An objective means of diagnosing anorexia nervosa and bulimia nervosa using 15N/14N and 13C/12C ratios in hair. Rapid Communications in Mass Spectrometry 20: 3367-3373.