Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial
What this study found
Prenatal vitamin D supplementation in late pregnancy did not reduce childhood wheeze, eczema, atopy, lung function abnormalities, or inflammatory markers at age 3 years. For wheeze ever, daily vitamin D was 11/56 (20) versus 14/50 (28) in control (RR 0.70, 95% CI 0.35 to 1.40; P = 0.31), while bolus vitamin D was 15/52 (29) versus 14/50 (28) (RR 1.03, 95% CI 0.56 to 1.91; P = 0.93). Most outcomes were null, but the bolus group had higher bronchodilator use (14/48 [29] vs 4/49 [8]; RR 3.57, 95% CI 1.27 to 10.09; P = 0.008) and more lower respiratory tract infection events (17/47 [36] vs 11/50…
- Study & population
- Randomized controlled trial in pregnant women attending St Mary's Hospital in London, United Kingdom, enrolled from April to November 2007.
- Intervention
- Pregnant women were randomized at 27 weeks' gestation to either oral ergocalciferol 800 IU daily until delivery or a single oral bolus of 200,000 IU cholecalciferol, compared with no vitamin D supplementation.
- Key limitation
- The active-arm sample sizes were small and several outcomes had substantial missing data or incomplete objective measurements, reducing precision and increasing the risk of chance findings.
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Open PDFOriginal abstract
Background Observational studies suggest high prenatal vitamin D intake may be associated with reduced childhood wheezing. We examined the effect of prenatal vitamin D on childhood wheezing in an interventional study. Methods We randomised 180 pregnant women at 27 weeks gestation to either no vitamin D, 800 IU ergocalciferol daily until delivery or single oral bolus of 200,000 IU cholecalciferol, in an ethnically stratified, randomised controlled trial. Supplementation improved but did not optimise vitamin D status. Researchers blind to allocation assessed offspring at 3 years. Primary outcome was any history of wheeze assessed by validated questionnaire. Secondary outcomes included atopy, respiratory infection, impulse oscillometry and exhaled nitric oxide. Primary analyses used logistic and linear regression. Results We evaluated 158 of 180 (88%) offspring at age 3 years for the primary outcome. Atopy was assessed by skin test for 95 children (53%), serum IgE for 86 (48%), exhaled nitric oxide for 62 (34%) and impulse oscillometry of acceptable quality for 51 (28%). We found no difference between supplemented and control groups in risk of wheeze [no vitamin D: 14/50 (28%); any vitamin D: 26/108 (24%) (risk ratio 0.86; 95% confidence interval 0.49, 1.50; P = 0.69)]. There was no significant difference in atopy, eczema risk, lung function or exhaled nitric oxide between supplemented groups and controls. Conclusion Prenatal vitamin D supplementation in late pregnancy that had a modest effect on cord blood vitamin D level, was not associated with decreased wheezing in offspring at age three years. Trial Registration Controlled-Trials.com ISRCTN68645785