Background: Obesity affects 18% of U.S. children. In a recent report, maternal consumption of ≥150 mg of caffeine per day during pregnancy was associated with increased odds for obesity in the offspring (odds ratio = 2.1 [95% confidence interval = 1.2-3.5]). If this association was causal, a considerable fraction of childhood obesity might be prevented by reduction of caffeine intake in pregnancy.
Methods: We studied 1986 mother-child pairs who were controls from a case-control study of caffeine metabolites and spontaneous abortion nested within the Collaborative Perinatal Project. Women were pregnant during 1959-1966, and children were followed with visits at 48 and/or 84 months of age, when height and weight were measured according to a standardized protocol. Serum was drawn at <20 and ≥26 weeks' gestation and assayed for paraxanthine (caffeine's primary metabolite) by high-performance liquid chromatography. Relative risks of obesity (body mass index ≥95th percentile for age and sex) were estimated by log-binomial or Poisson regression and adjusted for maternal age, race, education, smoking, prepregnant weight, diabetes in pregnancy, and gestational age at blood draw.
Results: Obesity prevalence was 11.7% at 48 months and 6.5% at 84 months. Associations of maternal serum paraxanthine and child obesity were nonlinear, and adjustment reduced the magnitude of all associations. The maximum relative risk (approximately 1.4) was for the association of paraxanthine drawn at <20 weeks with obesity at ages 48 and 84 months.
Conclusion: This study does not support an increased risk of childhood obesity with increasing maternal caffeine consumption during pregnancy.