101. The Genetic Risk For Body Mass Index And Weight Loss Behaviors

Abstract

Three genetic loci have been found to be involved with both body mass index (BMI) and anorexia nervosa, however, it is unknown if genetic risk for BMI is associated with unhealthy weight control behaviors. The objective of this study was to determine the association between genetic risk for obesity and weight loss behaviors in young adults. We analyzed data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) when participants were 18-26 years old. Genetic risk scores included 97 single nucleotide polymorphisms identified in published genome-wide association studies for BMI. Phenotypes included self-reported: 1) weight loss goals; 2) dieting; and 3) “unhealthy weight control behaviors” such as vomiting, fasting/skipping meals, or laxative/diuretic use to lose weight. Among 5728 subjects, genetic risk for obesity was associated with greater odds of weight loss attempts in females (OR 1.21, 95% confidence interval [CI] 1.12-1.30) and males (OR 1.33, 95% CI 1.19-1.47). Genetic risk for obesity was also associated with greater odds of dieting (females: OR 1.15, 95% CI 1.06-1.26; males: OR 1.30, 95% CI 1.14-1.48) and unhealthy weight control behaviors (females: OR 1.12, 95% CI 1.00-1.24; males: 1.37, 95% CI 1.16-1.63). The adjusted odds ratios for the association between genetic risk for obesity and weight loss attempts decreased (from 1.21 to 1.01 in females, 1.33 to 1.04 in males) after accounting for BMI, suggesting that the relationship may be mediated by BMI. Genetic risk for higher BMI was associated with weight loss attempts, dieting, and unhealthy weight control behaviors in both males and females; however, this association may be mediated by BMI. Further research on the genetic risk architecture on BMI and weight control behaviors may explain treatment nonresponse and inform joint treatment strategies.