Gene×dietary pattern interactions in obesity: analysis of up to 68,317 adults of European ancestry.

Summary, in English

Obesity is highly heritable. Genetic variants showing robust associations with obesity traits have been identified through genome-wide association studies. We investigated whether a composite score representing healthy diet modifies associations of these variants with obesity traits. 32 BMI- and 14 waist-hip ratio (WHR)-associated SNPs were genotyped and genetic risk scores (GRS) calculated in 18 cohorts of European ancestry (n=68,317). Diet score was calculated based on self-reported intakes of whole grains, fish, fruits, vegetables, nuts/seeds (favorable) and red/processed meats, sweets, sugar-sweetened beverages, fried potatoes (unfavorable). Multi-variable adjusted, linear regression within each cohort, followed by inverse variance-weighted fixed-effects meta-analysis was used to characterize: a) associations of each GRS with BMI and BMI-adjusted WHR; b) diet score modification of genetic associations with BMI and BMI-adjusted WHR. Nominally significant interactions (P=0.006-0.04) were observed between the diet score and WHR-GRS (but not BMI-GRS), two WHR loci (GRB14 rs10195252; LYPLAL1 rs4846567), and two BMI loci (LRRN6C rs10968576; MTIF3 rs4771122), for the respective BMI-adjusted WHR or BMI outcomes. Although the magnitudes of these select interactions were small, our data indicated that associations between genetic predisposition and obesity traits were stronger with a healthier diet. Our findings generate interesting hypotheses; however, experimental and functional studies are needed to determine their clinical relevance.