Nettleton, Jennifer A.; Follis, Jack L.; Ngwa, Julius S.; Smith, Caren E.; Ahmad, Shafqat; Tanaka, Toshiko; Wojczynski, Mary K.; Voortman, Trudy; Lemaitre, Rozenn N.; Kristiansson, Kati; Nuotio, Marja-Liisa; Houston, Denise K.; Perala, Mia-Maria; Qi, Qibin; Sonestedt, Emily; Manichaikul, Ani; Kanoni, Stavroula; Ganna, Andrea; Mikkila, Vera; North, Kari E.; Siscovick, David S.; Harald, Kennet; Mckeown, Nicola M.; Johansson, Ingegerd; Rissanen, Harri; Liu, Yongmei; Lahti, Jari; Hu, Frank B.; Bandinelli, Stefania; Rukh, Gull; Rich, Stephen; Booij, Lisanne; Dmitriou, Maria; Ax, Erika; Raitakari, Olli; Mukamal, Kenneth; Mannisto, Satu; Hallmans, Goran; Jula, Antti; Ericson, Ulrika; Jacobs, David R.; Van Rooij, Frank J. A.; Deloukas, Panos; Sjogren, Per; Kahonen, Mika; Djousse, Luc; Perola, Markus; Barroso, Ines; Hofman, Albert; Stirrups, Kathleen; Viikari, Jorma; Uitterlinden, Andre G.; Kalafati, Ioanna P.; Franco, Oscar H.; Mozaffarian, Dariush; Salomaa, Veikko; Borecki, Ingrid B.; Knekt, Paul; Kritchevsky, Stephen B.; Eriksson, Johan G.; Dedoussis, George V.; Qi, Lu; Ferrucci, Luigi; Orho-Melander, Marju; Zillikens, M. Carola; Ingelsson, Erik; Lehtimaki, Terho; Renstrom, Frida; Cupples, L. Adrienne; Loos, Ruth J. F.; Franks, Paul W.
(2015)
Obesity is highly heritable. Genetic variants showing robust associationswith 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. Totally, 32 body mass index (BMI)- and 14 waist-hip ratio (WHR)-associated single nucleotide polymorphismswere genotyped, and genetic risk scores (GRS) were 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 and fried potatoes (unfavorable). Multivariable 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-adjustedWHR and (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-adjustedWHR 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.