Vitamin D Supplementation, COPD and Asthma Exacerbations and Lung Function Decline.

Abstract

Background: It remains unclear whether supplementation with vitamin D reduces the risk of acute exacerbations of chronic obstructive lung disease (COPD) or asthma, major contributors to the world-wide burden of disease.

Objective: To compare effects of vitamin D with placebo supplementation for the prespecified primary endpoints (1) acute exacerbations of COPD and (2) decline in pulmonary function measures of airflow obstruction. Prespecified secondary endpoints included asthma exacerbations and control.

Methods: Lung VITAL (VITamin D and OmegA-3 TriaL) is an ancillary study of VITAL, a U.S. nationwide, randomized, placebo-controlled trial with a two-by-two factorial design, of vitamin D₃ (2000 IU per day) and marine n-3 fatty acids (1 g per day) among men 50 years and women 55 years of age or older. Of 25,871 randomized participants, 3632 at risk for respiratory exacerbations, including 1977 with COPD by diagnosis or symptoms and 1654 with self-reported asthma diagnosis, were followed annually for five years by self-administered respiratory questionnaire. Spirometry was performed at baseline and two years post-randomization by 1648 participants from twelve urban centers. Decline in forced expiratory volume in one second [FEV₁] and FEV₁/FVC (forced vital capacity) was measured between baseline and follow-up.

Results: Supplementation with vitamin D was not associated with lower risk of any primary or secondary end point. Over the five-year follow-up, the number of COPD exacerbations was 0.27/year in the vitamin D group and 0.25 /year in the placebo group (rate ratio 1.10; 95% confidence interval, 0.93 to 1.29). Over two-years' follow-up, supplementation was not associated with slower decline (ml/yr) in forced expiratory volume in one second (FEV₁).

Conclusions: Supplementation with vitamin D, compared to placebo, did not result in a lower rate of COPD exacerbations or improved pulmonary function in community-dwelling adults not selected for vitamin D deficiency.

Trial registration: Lung VITAL ClinicalTrials.gov number, NCT01728571. Protocol ID 2010-P-000622 .https://prevention.cancer.gov/clinical-trials/clinical-trials-search/nct01728571.