Gene x Behavior Interaction in the Look AHEAD Study
Condition: Obesity; Type 2 Diabetes
MeSH terms: Obesity
Study type: Observational

Summary: 
      The interplay of genetic and behavioral factors is critical to understanding obesity.
      Behavioral weight loss intervention has emerged as a key strategy in combating obesity.
      However, individuals differ in their degree of success in these programs 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 and high density lipoprotein
      cholesterol in response to behavioral intervention to help identify individuals that struggle
      with weight loss and cholesterol despite behavioral efforts.
    

Detailed description: 
      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.
    

Intervention name(s): Intensive lifestyle intervention; Diabetes support and education
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Lifestyle intervention focused on weight loss through diet and physical activity; Behavioral intervention focused on diabetes support and education
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        5,145 individuals who are overweight or obese, have type 2 diabetes and are enrolled in the
        Look AHEAD Study
      
Biospecimen description: 
      DNA obtained as part of the parent study
    
Keywords: Obesity; physical fitness; cholesterol levels; genetics; weight loss