Abstract
Animal models suggest that vitamin A deficiency affects lung development adversely and promotes airway hyperresponsiveness, and may predispose to an increased risk of asthma. We examined the long-term effects of vitamin A supplementation early in life on later asthma risk.
In 2006–2008, we revisited participants from two cohorts in rural Nepal who were enrolled in randomised trials of vitamin A supplementation. The first cohort received vitamin A or placebo for <16 months during their pre-school years (1989–1991). The second cohort was born to mothers who received vitamin A, β-carotene or placebo before, during and after pregnancy (1994–1997). At follow-up, we asked about asthma symptoms and performed spirometry.
Out of 6,421 subjects eligible to participate, 5,430 (85%) responded to our respiratory survey. Wheezing prevalence during the previous year was 4.8% in participants aged 9–13 yrs and 6.6% in participants aged 14–23 yrs. We found no differences between the vitamin A supplemented and placebo groups from either trial in the prevalence of lifetime or current asthma and wheeze or in spirometric indices of obstruction (p≥0.12 for all comparisons).
Vitamin A supplementation early in life was not associated with a decreased risk of asthma in an area with chronic vitamin A deficiency.
Footnotes
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Support Statement
This work was carried out by the Center for Human Nutrition, Department of International Health of the Johns Hopkins Bloomberg School of Public Health (Baltimore, MD, USA) and the Division of Pulmonary and Critical Care of the Johns Hopkins University, School of Medicine, The Johns Hopkins University (Baltimore) through the Nepal Nutrition Intervention Project-Sarlahi in collaboration with the National Society for Comprehensive Eye Care (Kathmandu, Nepal). This study was funded by the Bill and Melinda Gates Foundation (Seattle, WA, USA; grant number 614) and the Sight and Life Research Institute (Baltimore). The original maternal vitamin A or β-carotene supplementation trial (1994–1997) was conducted under the Vitamin A for Health Cooperative Agreement number HRN-A-00-97-00015-00 between the Johns Hopkins University and the Office of Health, Infectious Diseases and Nutrition of the US Agency for International Development (Washington, DC, USA), with additional support from Task Force Sight and Life (Basel, Switzerland). W. Checkley was further supported by a Clinician Scientist Award from the Johns Hopkins University and a Pathway to Independence Award from the National Heart, Lung and Blood Institutes (Baltimore; award number K99HL096955). The sponsors had no role in the study design, writing of the report or decision to submit the paper for publication.
Statement of Interest
None declared.
- Received January 14, 2011.
- Accepted April 26, 2011.
- ©ERS 2011