title: Genetic susceptibility to obesity and diet intakes: association and interaction analyses in the Malmö Diet and Cancer Study.
abstract: Gene-environment interactions need to be studied to better understand the obesity. We aimed at determining whether genetic susceptibility to obesity associates with diet intake levels and whether diet intakes modify the genetic susceptibility. In 29,480 subjects of the population-based Malmö Diet and Cancer Study (MDCS), we first assessed association between 16 genome-wide association studies identified obesity-related single-nucleotide polymorphisms (SNPs) with body mass index (BMI) and associated traits. We then conducted association analyses between a genetic risk score (GRS) comprising of 13 replicated SNPs and the individual SNPs, and relative dietary intakes of fat, carbohydrates, protein, fiber and total energy intake, as well as interaction analyses on BMI and associated traits among 26,107 nondiabetic MDCS participants. GRS associated strongly with increased BMI (P = 3.6 × 10(-34)), fat mass (P = 6.3 × 10(-28)) and fat-free mass (P = 1.3 × 10(-24)). Higher GRS associated with lower total energy intake (P = 0.001) and higher intake of fiber (P = 2.3 × 10(-4)). No significant interactions were observed between GRS and the studied dietary intakes on BMI or related traits. Of the individual SNPs, after correcting for multiple comparisons, NEGR1 rs2815752 associated with diet intakes and BDNF rs4923461 showed interaction with protein intake on BMI. In conclusion, our study does not provide evidence for a major role for macronutrient-, fiber- or total energy intake levels in modifying genetic susceptibility to obesity measured as GRS. However, our data suggest that the number of risk alleles as well as some of the individual obesity loci may have a role in regulation of food and energy intake and that some individual loci may interact with diet.
authors.affiliation: Diabetes and Cardiovascular Disease, Genetic Epidemiology, Department of Clinical Sciences in Malmö, Clinical Research Centre, Lund University, 91:12, Jan Waldenströms gata 35, 205 02, Malmö, Sweden.
authors.forename: Gull
authors.initials: G
authors.lastname: Rukh
authors.forename: Emily
authors.initials: E
authors.lastname: Sonestedt
authors.forename: Olle
authors.initials: O
authors.lastname: Melander
authors.forename: Bo
authors.initials: B
authors.lastname: Hedblad
authors.forename: Elisabet
authors.initials: E
authors.lastname: Wirfält
authors.forename: Ulrika
authors.initials: U
authors.lastname: Ericson
authors.forename: Marju
authors.initials: M
authors.lastname: Orho-Melander