Vitamin D for prevention of respiratory tract infections: A systematic review and meta-analysis

Vitamin D for prevention of respiratory tract infections: A systematic review and meta-analysis

Acute respiratory infection (ARI) is widespread not only in the paediatric age group but also in adults. Respiratory tract infections are the major cause of mortality and morbidity. There are limited options available for treatment and prevention of ARI. Antibiotics are the mainstay of treatment for pneumonia. In the developing countries, zinc and vitamin supplementation has been studied for the prevention and treatment of ARI. It has been shown that supplements of these micronutrients reduce the ARI rates though evidences are conflicting. Vitamin C (ascorbic acid) has also been used for the prevention and treatment of ARI despite the lack of convincing evidence of benefit.

Recent research suggested that vitamin D also has a potential role in the prevention of ARI by increasing immunity. In some observational studies, it was observed that low vitamin D level in blood is associated with the increased incidence of respiratory tract infections. There is a need to refine our knowledge about the functions of vitamin D in the prevention of respiratory tract infections in the light of clinical trials which were done to explore this phenomenon. Hence, we conducted this systematic review and meta-analysis to assess the role of vitamin D supplementation in prevention of ARI.

To explore the effect of vitamin D supplementation in prevention of respiratory tract infections on the basis of published clinical trials.

Materials and Methods: – Clinical trials were searched from various electronic databases. Five clinical trials were suitable for inclusion. Outcome was events of respiratory tract infections in Vitamin D group and placebo group. Data was reported as odds ratio with 95% confidence interval. Both random and fixed model was used for analysis. Analysis was done with the help of Comprehensive meta-analysis software 2.

Results: – Events of respiratory tract infections were significantly lower in vitamin D group as compared to control group according to random model. Results were similar in the fixed model. On separate analysis of clinical trials dealing with groups of children and adults, beneficial effect of vitamin D was observed in both, according to fixed model. On using random model beneficial effect persisted in children’s group but became nonsignificant in adults’ group.

Conclusion: – Vitamin D supplementation decreases the events related to respiratory tract infections. There is need of more well conducted clinical trials to reach to a certain conclusion.