Education as a moderator of genetic risk for higher body mass index: prospective cohort study from childhood to adulthood

Abstract

Objectives:The life-course development of body mass index (BMI) may be driven by interactions between genes and obesity-inducing social environments. We examined whether lower parental or own education accentuates the genetic risk for higher BMI over the life course, and whether diet and physical activity account for the educational differences in genetic associations with BMI.Subjects/Methods:The study comprised 2441 participants (1319 women, 3-18 years at baseline) from the prospective, population-based Cardiovascular Risk in Young Finns Study. BMI (kg/m 2) trajectories were calculated from 18 to 49 years, using data from six time points spanning 31 years. A polygenic risk score for BMI was calculated as a weighted sum of risk alleles in 97 single-nucleotide polymorphisms. Education was assessed via self-reports, measured prospectively from participants in adulthood and from parents when participants were children. Diet and physical activity were self-reported in adulthood.Results:Mean BMI increased from 22.6 to 26.6 kg/m 2 during the follow-up. In growth curve analyses, the genetic risk score was associated with faster BMI increase over time (b=0.02, (95% CI, 0.01-0.02, P