Association of maternal plasma folate and cardiometabolic risk factors in pregnancy with elevated blood pressure of offspring in childhood

BACKGROUND The prevalence of childhood elevated blood pressure (BP) has increased in the United States, particularly among African Americans. The influence of maternal plasma folate levels, alone or in combination with maternal cardiometabolic risk factors (hypertensive disorders, diabetes, and prepregnancy obesity), on child systolic BP (SBP) has not been examined in a prospective birth cohort. We hypothesize that adequate maternal folate levels can reduce the risk of elevated SBP in children born to mothers with cardiometabolic risk factors. METHODS This study included 1,290 mother-child dyads (875 African Americans (67.8%)) recruited at birth and followed prospectively up to age 9 years from 2003 to 2014 at the Boston Medical Center. Child SBP percentile was calculated according to US reference data and elevated SBP was defined as SBP ≥75th percentile. RESULTS Maternal folate levels, overall, were not associated with child SBP. However, we found a significant multiplicative interaction between maternal cardiometabolic risk factors and maternal folate levels (Pinteraction = 0.015) on childhood elevated SBP. Among children born to mothers with any cardiometabolic risk factors, those whose mothers had folate levels above (vs. below) the median had 40% lower odds of elevated childhood SBP (odds ratio = 0.60, 95% confidence interval: 0.40-0.90). The associations did not differ appreciably in analyses restricted to African Americans, and they were not explained by gestational age, size at birth, prenatal folate intake, or breastfeeding. CONCLUSIONS Findings from our urban minority birth cohort suggest that higher levels of maternal folate may help counteract the adverse associations of maternal cardiometabolic risk factors on child SBP.