Abstract MP59: Associations of Maternal Pre-pregnancy Body Mass Index and Gestational Weight Gain with Offspring Longitudinal Change in BMI

Abstract

Introduction A number of studies have demonstrated significant associations between changes in obesity-related phenotypes and subsequent risk of CHD. While accumulating evidence suggests that maternal pre-pregnancy body mass index (mppBMI) and gestational weight gain (GWG) may impact adult offspring adiposity, no study has examined their associations with longitudinal changes in obesity. Changes in obesity are likely to reflect genetic-environmental interactions and may have important implications for understanding CHD risk. Objectives We examined the associations of mppBMI and GWG with longitudinal change in offspring’s BMI and assessed whether these associations are explained in part by genetic effects. Methods We used a birth cohort of 1400 young adults born in Jerusalem, with extensive archival data as well as clinical information at age 32, and longitudinal change in BMI based on two examinations at ages 17 and 32. Genotyping of mothers and offspring was carried out for 180 candidate genes related to cardio-metabolic outcomes. We created genetic propensity scores using a subset of 388 SNPs from 53 adiposity-related genes that were predictive of the exposures and outcome, and fit linear regression models both with and without genetic scores to examine the associations of mppBMI and GWG with offspring change in BMI. Analyses used inverse probability weighting to account for a stratified sampling scheme (i.e. oversampling of offspring with low and high birth weight as well as of overweight and obese mothers). Results mppBMI was positively associated with change in BMI over time (p<0.001), independent of GWG and confounders; there was an increase of 0.21 kg/m 2 in BMI change per increase of one standard deviation (SD) in mppBMI. A one-SD change in GWG was associated with a 0.16 kg/m 2 BMI change, independent of mppBMI and confounders. These associations were maintained irrespective of offspring BMI at age 17. The association between mppBMI with offspring change in BMI was slightly attenuated with the addition of genetic scores in the model (b=0.213 vs. 0.187). In the GWG model, when adjusted for the genetic scores a substantial decrease of 28.2% in the coefficient for GWG was observed (b=0.163 vs. 0.117). Conclusions This study points to the strong relationship between maternal excess weight and weight gain in pregnancy with offspring change in body size from adolescence to adulthood. Our findings suggest that genetic factors account, in part, for the association between GWG and offspring longitudinal change in BMI. Mapping genes underlying these associations with longitudinal change in BMI may potentially lead to targeted intervention strategies to reduce CHD risk.