examination of the overlap between genetic and environmental risk factors for intentional weight loss and overeating

• Published in: The International journal of eating disorders 2009-09, Vol.42 (6), p.492-497
• Main Authors: Wade, Tracey D, Treloar, Susan A, Heath, Andrew C, Martin, Nicholas G
• Format: Article
• Language: English
• Subjects: Adult; Adult and adolescent clinical studies; Aged; Aged, 80 and over; Anorexia; Anorexia nervosa; Anorexia Nervosa - genetics; Anorexia Nervosa - psychology; Biological and medical sciences; body weight; Bulimia; bulimia nervosa; Bulimia Nervosa - genetics; Bulimia Nervosa - psychology; Diseases in Twins - genetics; Diseases in Twins - psychology; Eating behavior disorders; Eating disorders; eating habits; environment; Female; Females; gaining weight; genetic; Genetics; Humans; Hyperphagia - genetics; Hyperphagia - psychology; intentional weight loss; Interviews as Topic; Medical sciences; Middle Aged; overeating; Personality Assessment - statistics & numerical data; Phenotype; Psychology. Psychoanalysis. Psychiatry; Psychometrics; Psychopathology. Psychiatry; Risk Factors; Social Environment; twin; Twins; Twins, Dizygotic - genetics; Twins, Dizygotic - psychology; Twins, Monozygotic - genetics; Twins, Monozygotic - psychology; Weight control; Weight Loss
• ISSN: 0276-3478; 1098-108X
• DOI: 10.1002/eat.20668

OBJECTIVE:: To further our understanding of how intentional weight loss (IWL) and overeating are related, we examined the shared genetic and environmental variance between lifetime IWL and overeating. METHOD:: Interview data were available for 1,976 female twins (both members of 439 and 264 pairs of monozygotic and dizygotic twins, respectively), mean age = 40.61, SD = 4.72. We used lifetime diagnostic data for eating disorders obtained from a semistructured psychiatric telephone interview, examined in a bivariate twin analysis. Both lifetime behaviors were measured on a 3-point scale, where absence of IWL or overeating formed one anchor on the scale and lifetime anorexia nervosa (AN) and bulimia nervosa (BN) formed the opposite anchors, respectively. RESULTS:: In line with previous findings, a higher body mass index was significantly associated with the lifetime presence of IWL and/or overeating (odds ratio = 1.13, 95% confidence interval (CI): 1.08-1.19). The best fitting twin model contained additive genetic and nonshared environmental influence influencing both IWL and overeating, with correlations between these influences of 0.61 (95% CI: 0.35-0.92) and 0.24 (95% CI: 0.07-0.42), respectively. DISCUSSION:: About 37% of genetic risk factors were considered to overlap between IWL and overeating, and with only 6% of overlap between environmental risk factors. Thus, considerable independence of risk factors was indicated. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2009