Objective Epidemiological studies have shown that the peroxisome proliferator-activated receptor-gamma (PPAR-γ) pro12ala polymorphism is associated with obesity. We hypothesised thatPPAR-γ pro12ala influences prenatal and early postnatal growth.
Methods This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. Fetal growth was assessed by ultrasounds in early, mid and late pregnancy. Anthropometrics in infancy was assessed at birth and at the ages of 1.5, 6, 11, 14 and 18 months. Analyses were performed in 3436 children of caucasian ethnicity.
Results Genotype frequency distribution was 77.6% (homozygous pro12), 20.7% (heterozygous pro12/ala12), and 1.7% (homozygous ala12). Using dominant models, estimated fetal weight in late pregnancy and birth weight tended to be higher in the homozygous ala12 group than in pro12 allele carriers (differences 23 g; 95% CI −25 to 72 and 58 g; 95% CI −28 to 199, respectively). Postnatally, subjects in the homozygous ala12 group remained consistently heavier. Differences at 14 and 18 months in weight were (593 g; 95% CI 196 to 990 and 487 g; 95% CI 25 to 950, respectively). Similar effect estimates were found using additive models. No significant differences were found in height or head circumference.
Conclusions This study suggests that PPAR-γ pro12ala is associated with increased growth rates from birth until the age of 1.5 years. The previously found association with obesity in later life may start during the first years of life.