Gene x Behavior Interaction in the Look AHEAD Study

The interplay of genetic and behavioral factors is critical to understanding obesity. Obesity is a major public health problem, with millions of Americans suffering from weight-related health complications, including Type 2 diabetes, coronary heart disease, hypertension, and osteoarthritis. Behavioral weight loss intervention has emerged as a key strategy in combating obesity and the associated health consequences. However, individuals differ in their degree of success in these programs even if they make the recommended behavioral changes and genetic factors are known to play a role. In this application, the investigators propose to identify specific genes that predict individual differences in weight loss in response to behavioral intervention to help identify individuals who struggle with weight loss despite behavioral efforts. Specifically, the investigators will determine whether obesity genes interact with lifestyle intervention in predicting weight loss at year 1 of the Look AHEAD trial, an NIH-funded, multi-center randomized controlled trial with the primary goal of determining whether weight loss achieved through an intensive lifestyle intervention can reduce cardiovascular morbidity and mortality among persons with type 2 diabetes. At year 1, participants assigned to Intensive Lifestyle Intervention (ILI), focusing on changes in diet and physical activity, lost an average of 8.6% of their weight (N = 2,496; 97.1% follow-up) relative to losses of 0.7% among individuals assigned to the Diabetes Support and Education (DSE) group (N= 2,463, 95.7% follow-up), who received diabetes support and education groups alone. Consent for genetic analyses was provided by 3,759 participants. Genotype data from the IBC chip, a genotyping platform including 50,000 single nucleotide polymorphisms (SNPs) from ~2,600 genes relevant to cardiovascular disease, lipid metabolism, diabetes and obesity, will allow us to test the central hypothesis that genes that predispose to obesity interact with lifestyle treatment to influence weight loss following intensive lifestyle intervention. The investigators will also determine whether genes related to high density lipoprotein (HDL) cholesterol predict the degree of improvement in HDL in response to the behavioral intervention. The investigators conduct these aims with the explicit goal of bringing together a team with expertise in behavioral research, genetic epidemiology and molecular biology to create transdisciplinary researchers who are able to bridge across the disciplines and identify key gene x behavior interactions in the context of the Look AHEAD trial.