The aim of the study is to examine the effect of PPAR-gamma-2 gene polymorphism Pro12Ala and early postnatal growth and to see whether the effect is modified by breastfeeding. For this purpose we will require birth weight and postnatal growth data, and PPAR-gamma-2 genotype.

First, we will look at cross-sectional differences of growth characteristics at various ages in both cohorts. Then, will we examine longitudinally differences in growth rate (defined as grams/months) from birth to 5 years (3 years in Generation R) between the genotypes. Finally, we will explore whether there is an interaction effect between breastfeeding duration and genotype on growth characteristics.