Abstract
Animal models suggest that vitamin A deficiency affects lung development adversely and promotes airway hyper-responsiveness, 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 enrolled in randomized 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, beta-carotene or placebo before, during and after pregnancy (1994–1997). At follow-up, we asked about asthma symptoms and performed spirometry.
Of 6421 eligible to participate, 5430 (85%) responded to our respiratory survey. Wheezing prevalence during the past year was 4.8% in participants aged 9–13 years and 6.6% in participants aged 14–23 years. We found no differences between the vitamin A supplemented versus placebo groups from either trial in the prevalences 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.
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