Vitamin A supplementation in infectious diseases: a meta-analysis.

OBJECTIVE

To study the effect of vitamin A supplementation on morbidity and mortality from infectious disease.

DESIGN

A meta-analysis aimed at identifying and combining mortality and morbidity data from all randomised controlled trials of vitamin A.

RESULTS

Of 20 controlled trials identified, 12 trials were randomised trials and provided "intention to treat" data: six community trials in developing countries, three in children admitted to hospital with measles, and three in very low birth weight infants. Combined results for community studies suggest a reduction of 30% (95% confidence interval 21% to 38%; two tailed p < 0.0000001) in all cause mortality. Analysis of cause specific mortality showed a reduction in deaths from diarrhoeal disease (in community studies) by 39% (24% to 50%; two tailed p < 0.00001); from respiratory disease (in measles studies) by 70% (15% to 90%; two tailed p = 0.02); and from other causes of death (in community studies) by 34% (15% to 48%; two tailed p = 0.001). Reductions in morbidity were consistent with the findings for mortality, but fewer data were available.

CONCLUSIONS

Adequate supply of vitamin A, either through supplementation or adequate diet, has a major role in preventing morbidity and mortality in children in developing countries. In developed countries vitamin A may also have a role in those with life threatening infections such as measles and those who may have a relative deficiency, such as premature infants.