Eating Disorder Prepared by Valerie Forman Summary

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1 Eating Disorder Prepared by Valerie Forman Summary Eating disorders have received increasing levels of research, clinical, and media attention over the past several decades. The most well-known disorders include Anorexia Nervosa (AN), characterized by self-starvation, body image distortion, and extremely low body weight, and Bulimia Nervosa (BN), characterized by mass food consumption called a binge and purgatory behaviors such as vomiting or laxative use to rid the body of the calories consumed during the binge. A third type of eating disorder, Binge-Eat Disorder (Du Boullay, Bardier, Cheneau, Bortolasso, & Gaubert, 1984) (Du Boullay et al., 1984), is not a formally diagnosable disorder according to the Diagnostic and Statistical Manual-4 th edition (Hsu, 1990), but is listed in the appendix along with associated criteria. The Diagnostic and Statistical Manual-4 th edition (1994) criteria for AN consist of having a weight that is less than 85% of that expected, having an intense fear of gaining weight or becoming fat, having a body image distortion, and amenorrhea (in post menarcheal females) for at least three months. In addition, the DSM-IV defines two clinical subtypes: 1. Restricting Type: during the current episode of Anorexia Nervosa, the person has not regularly engaged in binge-eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas), and 2. Binge-Eating/Purging Type: during the current episode of Anorexia Nervosa, the person has regularly engaged in binge-eating or purging behavior (i.e., self-induced vomiting or the misuse of laxatives, diuretics, or enemas) The main presenting features of AN include mental impairment that accompanies the morbid fear of becoming fat and insistence of a too-large body such as low self-esteem, guilt, worthlessness, and obsessive thoughts about food and body image. Behavioral indications include hyperactivity and increased exercise and/or strange food preparing and eating rituals. In addition, individuals with AN typically evidence social withdrawal, isolation, and a lack of interest in usual activites and, in particular, sex. Until recently, there have been no community-based studies on anorexia nervosa (Lee, Leung, Lee, Yu, & Leung, 1996). Since anorexia nervosa has a relatively low base rate, epidemiologic studies require the use of large population samples in order to make accurate assessments (Friedman, Wilfley, Pike, Striegel-Moore, & Rodin, 1995). The secretive nature of this condition further inhibits study participation and can cause underreporting of actual AN cases. In addition, the scarcity of empirical data that objectively addresses the possible causal mechanisms of anorexia nervosa continues to obscure its etiology (Fairburn et al., 1995). Lifetime prevalence estimates of Bulimia Nervosa in the U.S. range from 1.1%-4.4% in females (APA Workgroup on Eating Disorders, 2000). The discrepancy in prevalence rates most likely results from the differences in assessment methods and definitions of BN used in different studies. The disorder is particularly prevalent on college campuses, with 1.3% of college females meeting current criteria for a DSM-III-R diagnosis of BN in 1987 (Schotte & Stunkard, 1987) and 1990 (Pemberton, Vernon, & Lee, 1996). After consuming massive quantities of food, people with bulimia nervosa purge by vomiting or laxative use, a process that usually prevents

2 obesity but also does not cause weight loss since the body begins to digest calories as soon as they enter the body; hence, sufferers of BN are typically of average weight. Bulimia, which means "ox-hunger," was first named as a disorder in 1980, although episodes of immense ingestion of food followed by self-induced vomiting date back to the Middle Ages. The DSM- IV (1994) diagnosis of Bulimia Nervosa requires recurrent episodes of binge eating and recurrent inappropriate compensatory behavior in order to prevent weight gain that occur, on average, at least twice a week for 3 months. Individuals suffering from bulimia nervosa also self-evaluate based on body shape and weight. Like Anorexia Nervosa, there are two diagnosable types of bulimia nervosa: 1. Purging type: the person has regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas during the current episode, and 2. Non-purging type: the person has used other inappropriate compensatory behaviors, such as fasting or excessive exercise, but has not regularly engaged in self-induced vomiting or the misuse of laxatives, diuretics, or enemas during the current episode. The lifetime prevalence of clinically significant anorexia nervosa and bulimia nervosa in the U.S. has increased over the past century to about 0.5%-1% and 3%, respectively, indicating the presence of a significant public health problem (Friedman et al., 1995). Incidence estimates for AN range from 1-10 cases per year in 100,00 experiencing AN onset (Friedman et al., 1995). Some propose that the current cultural ideal of thinness present in the today s cohort of younger women has caused depression and eating disorders at higher rates compared with women in the past (Wakeling, 1996). A study of the incidence of AN in Rochester, MN between 1980 and 1990 found an overall estimate of 8.2 per 100,000 person years, with 14.6 per 100,000 person years among females and 1.8 per 100,000 person years among males (Lucas, Beard, O'Fallon, & Kurland, 1991). For BN, the incidence rose from 7 per 100,000 person-years in 1980 to 49.3 per 100,000 person years in This upward trend, however, did not continue throughout the 1980's, with estimates leveling off around 30 per 100,000 for the remainder of the study period, with overall adjusted rates of 26.5 per 100,000 person years for females and 0.8 per 100,000 person years for males (Soundy, Lucas, Suman, & Melton, 1995). These increasing trends, however, may be grossly over-exaggerated, as evidence by data collected on AN psychiatric patients from Though the number of first admissions for women rose significantly with time, age-period-cohort analysis revealed that an increase in the number of young women in the population caused the trend, rather than an increase in the risk of morbidity (McCarthy, 1990). Recent loosening of the diagnostic criteria for the weight loss component of AN from 25% of normal expected weight in the DSM-III-R to 15% of normal expected weight in DSM-IV may have affected the trends as well. Subthreshold disordered eating estimates are higher, especially within females and adolescents. Researchers have determined a point prevalence of 4-10% and a lifetime prevalence of 8-15% for partial syndrome anorexia in young women, characterized by the presence of AN symptoms that fall short of a clinical eating disorder diagnosis, usually in terms of weight loss or amenorrhea (Williams & King, 1987; Button & Whitehouse, 1981; King, 1989). Rates from a recent study of 7 th, 9 th, and 11 th grade public school students conducted in the Northeastern United States found that 7.4% of the girls and 3.1% of the boys had used laxatives or dieuretics, diet pills, and/or had self-induced vomiting in the prior week (Neumark-Sztainer, Story, Falkner, Beuhring, & Resnick, 1999). In a nationally representative sample of 5 th through 12 th graders, the calculated rates were also high, with 13% of girls and 7% of boys reported these types of

3 disordered eating (Neumark-Sztainer & Hannan, 2000). For this report, the terms anorexia nervosa, bulimia nervosa, and eating disorder were combined, individually, with each keyword during the initial search procedure. Of the 867 studies meeting initial search criteria, only 42 studies merited further investigation. Very few prospective studies have been conducted. Over half of the investigated studies (22) were review articles, which were searched to identify any articles the original search procedure missed. An additional 10 of the studies that contained individual eating disorder symptoms as outcome variables were excluded since inclusion criteria required syndromes, as were 10 studies that only assessed prevalence or incidence. The five studies that did meet inclusion criteria were by Wood et al. (1994), Button et al. (1996), Eaton et al. (2001), and two by Killen et al. (1994, 1996). The two studies by Killen et al. and the study by Button et al. were completely prospective follow-up studies, while the study by Wood et al. was a follow-up prevalence study. Eaton et al. s study was ambidirectional, comparing the rates of ICD-8 eating disorders between those with and without various prenatal and perinatal risk factors. Each of these studies provided relative risk estimates and 95% confidence intervals with the exception of the study conducted by Wood et al. Mean scores on self-reported tests between those who developed partial syndrome eating disorders were compared using F-tests, which were converted into odds ratio estimates using the methods of Lipsey and Wilson (2001). Confidence intervals could not be calculated without significant amounts of error, so individual odds ratios were plotted on the forest plots. Investigated risk factors include weight concerns, low self-esteem, unhealthy eating attitudes, mother s age at birth, birth weight/growth risk, mother s parity, mother s previous abortion(s), and low apgar score five minutes after birth. Unhealthy weight concerns had the strongest relationship with eating disorders, although the estimate was manipulated from the Wood et al. study, and, thus, may not be as reliable as the estimates calculated by the other identified studies. Other significant predictors of eating disorders included weight concerns, low self-esteem, and being born very light and growing slowly (as compared to being of normal weight at birth and growing normally). The study by Eaton et al. did not find that mother s age, mother s parity, mother s previous abortions, and low apgar scores five minutes after birth were significant predictors of eating disorders. Of note is that all of the studies with the exception of Eaton et al. s used partial syndrome, and not full-criteria, eating disorders as outcome variables. Studies using valid methodology to assess risk factors of eating disorders using prospective, population-based designs are scarce. In order to develop new and improve upon existing prevention programs, much more research is needed to determine risk factors of eating disorders. With the exception of the study by Eaton et al., none of the studies included males. Research using eating disorder syndromes, both partial-syndrome and syndromes meeting clinical diagnosis of eating disorders, is needed. In addition, population-based studies that use methods capable of producing relative risk estimates are required to ensure the valid identification of risk factors. Overall, there is very little prospective research on eating disorders. There is considerable room for improvement in this area, especially since the magnitude of eating disorders remains high in our country.

4 Selection Figure for Eating Disorders 867 studies matching the keywords 825 excluded for not meeting criteria 42 studies reviewed for inclusion criteria 22 Reviews excluded 10 excluded, no syndrome outcome 10 prevalence studies excluded 5 Studies for inclusion

5 Evidence Tables for Eating Disorders

6 Eating disorders Risk Factor: Weight concerns Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/ Measure Factor (95% CI) Adjustment Killen, J.D., et al 1996 Completely prospective Community sample of ninth cohort study grade girls from California Measure years Partial syndrome eating disorders DSM-III- R, ED, EDE SR/CI Weight concerns Highest quartile versus other Females Highest quartile Females Lower 3 quartiles RR=3.83 ( ) 1.0 (ref) Killen, J.D., et al 1994 Completely prospective Sixth and 7 th grade girls years Symptomatic by criteria for ED SR/CI weight concerns cohort study from CA Highest quartile versus lowest Females Highest quartile Females Lowest quartile RR=5.47 ( ) 1.0 (ref)

7 Risk factor: Low self-esteem Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/ Measure Measure Factor (95% CI) Adjustment 1996 Completely Schoolgirls years EAT Females Score of RR=3.13 prospective aged pathology 3+/6 ( ) cohort study (20+/26) Button, E.J. et al SR Rosenberg self-esteem scale Females Score of 0-2/6 1.0(ref) Wood, A., et al 1994 Follow-up prevalence Cohort of girls from 1 private school. 16 high risk (EAT>22) versus 17 lower risk (EAT<15) 33 2 years Partial syndrome ED (Button/ Whitehouse criteria) SR/CI SCANS general dissatis- faction/selfesteem Females Mean SCAN scores compared Females OR=2.28

8 Risk factor: unhealthy eating attitudes Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/Measure Measure Factor (95% CI) Adjustment Wood, A., et al 1994 Follow-up prevalence Cohort of girls from 1 private school. 16 high risk (EAT>22) versus 17 lower risk (EAT<15) 33 2 years Partial syndrome ED (Button/ Whitehouse criteria SR/CI EAT- 26 eating attitudes test (continuous) Mean EAT scores compared OR=15.3 Risk factor: mother's age Pub Study Sample Sample Study Outcome Risk Factor OR/RR Author Date Design Description Size Period Criteria/Measure Measure Risk (95% CI) Adjustment Eaton, W., et al 2001 Ambidirectional All births in Denmark's Med Birth Register 3420 plus Linked to Danish Psychiatric Register and 10% of all single-born births in the reference population ICD-8 eating disorders Factor Age in years <20 years none Gender, year of years 35 years + RR=0.37 ( ) birth, other 1.00 variables in model

9 Risk factor: birth weight/growth risk Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/Measure Measure Factor (95% CI) Adjustment Eaton, W., et al 2001 Ambidirectional All births in Denmark's Med Birth Register Linked to Danish Psychiatric Register and 10% of all single-born births in the ref pop n plus ICD-8 eating disorders Weight in grams and quintile of ref Population with same age and sex ref population with same age and sex Normal/ normal (ref) Very light/slow Light/slow 1.00 Gender, year of birth, other RR=3.49 ( ) RR=1.15 ( ) Normal/fast RR=0.59 ( ) Heavy/fast RR=0.28 (0-2.1) variables in model

10 Risk factor: Parity Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/Measure Measure Factor (95% CI) Adjustment 2001 Ambidirectional All births in 3420 ICD-8 eating Number of Gender, Denmark's plus disorders previous year of Eaton, W., et al Med Birth Register Linked to Danish Psychiatric Register and 10% of all Single-born births in the Ref. pop n pregnancies 1 or 2 RR=0.8 ( ) 3 + RR=1.14 ( ) birth, other variables in model

11 Risk factor: previous abortion Pub Study Sample Sample Study Outcome Risk Factor Risk OR/RR Author Date Design Description Size Period Criteria/Measure Measure Factor (95% CI) Adjustment Eaton, W., et al 2001 Ambidirectional All births in Denmark's Med Birth Register Linked to Danish Psychi. Register and 10% of all Single-born births in the Ref. pop n plus ICD-8 eating disorders One or more previous provoked No 1.00 Gender, year of birth, other abortions Yes RR=0.85 ( ) variables in model

12 Risk factor: low apgar (5 minute) score Pub Study Sample Sample Study Outcome Risk Factor OR/RR Author Date Design Description Size Period Criteria/Measure Measure Risk (95% CI) Adjustment Eaton, W., et al 2001 Ambidirectional All births in Denmark's Med Birth Register Linked to Danish Psychi. Register and 10% of all Single-born births in the Ref. pop n plus ICD-8 eating disorders Low Apgar score 5 minutes after Factor No 1.00 Gender, year of birth, other birth Yes RR=2.74 ( ) variables in model

13 Risk Factors for Subclinical Eating Disorders Low Self Esteem Hued Forest Plot Study name Button et al., 1996 Wood et al., 1994 CI UL LL EST Relative Risk/Odds Ratio Button et al., 1996:Rosenberg 3+/6 versus 0-2/6. Relative Risk. Wood et al., 1994: Mean SCANS score conversion. Odds Ratio.

14 Risk Factors for Subclinical Eating Disorders Weight Concerns and Unhealthy Eating Attitudes Color Category and Hued Forest Plot Weight Concerns a Risk Factor Weight Concerns b Unhealthy Eating Attitudes c CI UL LL EST Relative Risk/Odds Ratio a Killen et al., 1994: Weight concerns (Highest quartile versus lowest quartile). Relative Risk. b Killen et al., 1996: Weight concerns (Highest quartile versus lower three quartiles). Relative Risk. c Wood et al., 1994: Unhealthy eating attitudes (Mean EAT score conversion). Odds Ratio.

15 Risk Factors for ICD-8 Eating Disorders Prenatal and Perinatal Factors Color Category Forest Plot Mother's age Risk Factor Birth wt./growth Parity Previous abortion Low apgar 5 minute CI UL LL EST Relative Risk Eaton et al., 2001 Mother s age: 35 years or older vs years old Birth weight/growth: Very light/slow vs. Normal/normal Parity: 3 or more previous pregnancies vs. 0 Previous provoked abortion: Yes vs. No Low apgar score (5 minutes after birth): Yes vs. No

16 Eating Disorders Bibliography Button, E.J., Sonuga-Barke, E.J., Davies, J., & Thompson, M. (1996). A prospective study of self-esteem in the prediction of eating problems in adolescent schoolgirls: questionnaire findings. Br J Clin Psychol, 35 ( Pt 2), Eaton, W.W., Mortensen, P.B., Thomsen, P.H., & Frydenberg, M. (2001). Obstetric complications and risk for severe psychopathology in childhood. J Autism Dev Disord, 31(3), Killen, J.D., Taylor, C.B., Hayward, C., Wilson, D.M., Haydel, K.F., Hammer, L.D., Simmonds, B., Robinson, T.N., Litt, I., & Varady, A. (1994). Pursuit of thinness and onset of eating disorder symptoms in a community sample of adolescent girls: a three-year prospective analysis. Int J Eat Disord, 16(3), Killen, J.D., Taylor, C.B., Hayward, C., Haydel, K.F., Wilson, D.M., Hammer, L., Kraemer, H., Blair-Greiner, A., & Strachowski, D. (1996). Weight concerns influence the development of eating disorders: a 4-year prospective study. J Consult Clin Psychol, 64(5), Wood, A., Waller, G., & Gowers, S. (1994). Predictors of eating psychopathology in adolescent girls. US: John Wiley and Sons Inc.