Prenatal folic acid and risk of asthma in children: a systematic review and meta-analysis

Abstract

Background Childhood asthma has become a critical public health problem because of its high morbidity and increasing prevalence. The impact of nutrition and other exposures during pregnancy on long-term health and development of children has been of increasing interest. Objective We performed a systematic review and meta-analysis of the association of folate and folic acid intake during pregnancy and risk of asthma and other allergic outcomes in children. Design We performed a systematic search of 8 electronic databases for articles that examined the association between prenatal folate or folic acid exposure and risk of asthma and other allergic outcomes (eg, allergy, eczema, and atopic dermatitis) in childhood. We performed a meta-analysis by using a random-effects model to derive a summary risk estimate of studies with similar exposure timing, exposure assessment, and outcomes. Results Our meta-analysis provided no evidence of an association between maternal folic acid supplement use (compared with no use) in the prepregnancy period through the first trimester and asthma in childhood (summary risk estimate: 1.01; 95% CI: 0.78, 1.30). Because of substantial heterogeneity in exposures and outcomes, it was not possible to generate summary measures for other folate indicators (eg, blood folate concentrations) and asthma or allergy-related outcomes; however, the preponderance of primary risk estimates was not elevated. Conclusions Our findings do not support an association between periconceptional folic acid supplementation and increased risk of asthma in children. However, because of the limited number and types of studies in the literature, additional research is needed.

Early-life origins of chronic respiratory diseases: understanding and promoting healthy ageing

“…Studies on folic acid intake during pregnancy and asthma in children have also generally found no association between the two [82][83][84][85]. According to several large birth cohort studies, vitamin D intake or plasma levels during pregnancy are generally not associated with childhood asthma or lung function [86][87][88][89], and an RCT examining the effects of vitamin D supplementation during pregnancy (n5180) found no significant difference in children's wheezing at 3 years of age [90].…”

Maternal Folate Intake during Pregnancy and Childhood Asthma in a Population-based Cohort

“…This literature has been summarized, in several reviews, as conflicting, with limitations caused by heterogeneity in classification of folate intake, the time periods considered for exposure and disease development, and outcome definitions (5)(6)(7)(8). Two more recent studies reported associations between asthma in children older than 4 years of age and the use of folic acid supplements containing 1,000 mg or more during pregnancy (9,10).…”

Nutritional Influences on Epigenetic Programming

“…Another Australian study found that infants exposed in utero to more than 500 mg/day of maternal folic acid supplementation during late pregnancy (third trimester) were more likely to develop eczema during infancy. 47 A recent meta-analysis 48 (cohort and case-control studies; no RCTs), found no evidence of an association between maternal folic acid supplementation use in the periconceptional period (before and during the first trimester of pregnancy) and asthma during childhood (0-8 years) in the offspring. Thus it seems that the timing of exposure to folate supplementation in utero may be critical with regard to childhood allergic disease outcomes.…”