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Meta-Analysis
. 2013 Nov;98(5):1272-81.
doi: 10.3945/ajcn.113.065623. Epub 2013 Sep 4.

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

Krista S Crider  1 , Amy M Cordero, Yan Ping Qi, Joseph Mulinare, Nicole F Dowling, Robert J Berry
Affiliations
Meta-Analysis

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

Krista S Crider et al. Am J Clin Nutr. 2013 Nov.

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.

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Conflict of interest statement

The authors’ responsibilities were as follows—KSC, AMC, NFD, and RJB: designed the research; KSC, AMC, YPQ, and JM: conducted the research; KSC and AMC: analyzed data and wrote the manuscript; and KSC: had primary responsibility for the final content of the manuscript. None of the authors had a conflict of interest.

Figures

FIGURE 1
FIGURE 1
Study selection process flowchart.
FIGURE 2
FIGURE 2
Random-effects meta-analysis of the association between maternal folic acid supplement use (compared with no use) in the periconceptional period through the first trimester of pregnancy and asthma in childhood. Black squares represent point estimates, and the size of each square is proportional to the weight of the study in the analysis. Horizontal lines represent CIs. The black diamond represents the summary effect. CC, case-control.
FIGURE 3
FIGURE 3
Random-effects meta-analysis of the association between maternal folic acid supplement use (compared with no use) in the periconceptional period through the first trimester of pregnancy and asthma or wheezing in childhood. Black squares represent point estimates, and the size of each square is proportional to the weight of the study in the analysis. Horizontal lines represent CIs. The black diamond represents the summary effect. CC, case-control.
See this image and copyright information in PMC

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