Vitamin A supplementation and child mortality. A meta-analysis.

OBJECTIVE: A two-part meta-analysis of studies examining the relationship of vitamin A supplementation and child mortality. DATA SOURCES: We identified studies by searching the MEDLARS database from 1966 through 1992 and by scanning Current Contents and bibliographies of pertinent articles. STUDY SELECTION: All 12 vitamin A controlled trials with data on mortality identified in the search were used in the analysis. DATA EXTRACTION: Data were independently extracted by two investigators who also assessed the quality of each study using a previously described method. DATA SYNTHESIS: We formally tested for heterogeneity across studies. We pooled studies using the Mantel-Haenszel and the DerSimonian and Laird methods and adjusted for the effect of cluster assignment of treatment groups in community-based studies. Vitamin A supplementation to hospitalized measles patients was highly protective against mortality (DerSimonian and Laird odds ratio, 0.39; 95% confidence interval, 0.22 to 0.66; P = .0004) (part 1 of the meta-analysis). Supplementation was also protective against overall mortality in community-based studies (DerSimonian and Laird odds ratio, 0.70; clustering-adjusted 95% confidence interval, 0.56 to 0.87; P = .001) (part 2 of the meta-analysis).
CONCLUSIONS: Vitamin A supplements are associated with a significant reduction in mortality when given periodically to children at the community level. Factors that affect the bioavailability of large doses of Vitamin A need to be studied further. Vitamin A supplements should be given to all measles patients in developing countries whether or not they have symptoms of vitamin A deficiency.