PURPOSE OF THE STUDY.
To evaluate the relationship between maternal folate exposure and the development of allergic and respiratory disease in early childhood.
The study group included 917 pregnant women-child pairs from the Mothers and Children’s Environmental Health study in South Korea. Exclusion criteria included gestational age <37 weeks, pregnancy complications including hypertension, gestational diabetes, intrauterine growth retardation, twins, or congenital anomaly.
Maternal dietary intake was assessed by questionnaire. Maternal serum folate levels were prospectively measured during mid- and late pregnancy and categorized as high or low relative a median value. Atopic markers (serum total immunoglobulin E, eosinophil count, interleukin-10) and folate levels were measured in cord blood (CB) and in children at 24 months old and analyzed as high or low relative to a median value. Atopic dermatitis (AD), asthma, and lower respiratory tract infections (LRTI) were assessed via a questionnaire at 6, 12, and 24 months of age.
High folate levels in midpregnancy were associated with lower risk for increased CB eosinophil count, and high folate levels in mid- and late pregnancy were more associated with high CB interleukin-10. There was no significant association between folate levels in mid- or late pregnancy and child biomarker levels at 24 months of age. High folate levels in midpregnancy were associated with decreased risk of AD in children at 24 months but not at 6 and 12 months of age. Similarly, a decreased risk of LRTIs in children at 6 months of age was observed in the high-folate group at midpregnancy, after adjusting for maternal age, BMI, atopic history, urinary cotinine levels, infant’s gender, gestational age, and breastfeeding. There was no association between folate levels in the children and the prevalence of AD or LRTIs.
High maternal serum folate levels in midpregnancy were associated with a decreased risk of LRTIs and AD in early childhood, but there is a conflicting association with atopic biomarkers.
There have been inconsistent reports about folic acid supplementation in pregnancy and the risk for LRTIs and atopic disease. This study suggests that the timing of maternal folate supplementation (mid- vs late pregnancy) may affect development of allergic disease and LRTIs in early childhood. The strengths of this study include adjustment for variables such as history of atopy and breastfeeding as well as its prospective nature. However, weaknesses include recall bias, subjective report of atopic diagnosis, the short study period, and exclusion of asthma, another allergic disease, due to low statistical power. The authors also did not address optimal dosing of folic acid and folate level during pregnancy given that this may also affect outcomes.
- Copyright © 2015 by the American Academy of Pediatrics