Abstract

Objective We examined whether the PPARγ2 Ala12 allele influences growth in early life and whether this association is modified by breastfeeding.

Research Design and Methods This study was embedded in the Generation R Study, a prospective cohort study from early fetal life onwards. PPARγ2 was genotyped in DNA obtained from cord-blood samples in 3,432 children. Information about breastfeeding was available from questionnaires. Weight, head circumference and (femur) length were repeatedly measured in second and third trimesters of pregnancy, at birth and at the ages of 1.5, 6, 11, 14 and 18 months.

Results Genotype frequency distribution was 77.6% (Pro12Pro), 20.7% (Pro12Ala), and 1.7% (Ala12Ala). Growth rates in weight from second trimester of pregnancy to 18 months were higher amongst the Pro12Ala and Ala12Ala compared to Pro12Pro carriers (differences: 1.11 (95% confidence interval (CI): 0.47, 1.74) and 2.65 (95%CI: 0.45, 4.87) grams/week, respectively). We found an interaction between genotype and breastfeeding duration (p-value interaction <0.0001). In infants who were breastfed for at least four months, PPARγ2 Pro12Ala was not associated with growth rate. When breastfeeding duration was shorter than two months or between two and four months, growth rate was higher in Ala12Ala subjects than Pro12Pro (differences: 9.80 (95%CI: 3.97, 15.63) and 6.32 (95%CI: -1.04, 13.68) grams/week, respectively).

Conclusions The PPARγ2 Ala12 allele is associated with an increased growth rate in early life. This effect may be influenced by breastfeeding duration. Further studies should replicate these findings, identify the underlying mechanisms, and assess whether these effects persist into later life.