Effects of Vitamin A supplementation on child morbidity: a twenty-year time series analysis in the northeastern region of Brazil.

The present study aimed to determine the prevalence of supplementation between 1987 and 2007, and to measure the impact of this on morbidity. Five sequential cross-sectional studies in a 20-year time span were analyzed. Each had a sample of 8,000 domiciles representative of Ceará, in northeastern Brazil. Data were analyzed with descriptive statistics, followed by bivariate and multivariate analyses. Increases in coverage, ranging from 9.6 to 65.8 % were verified, and the study found that the impact of supplementation in reducing morbidity may not be significant. The study also found that supplementation may be associated with higher frequency of certain morbidities (OR 1.8, CI 95 % 1.20-2.95). When the supplementation variable was adjusted for socioeconomic factors, the risk was higher for diarrhea (OR 5.56, CI 95 % 2.63-11.75). The study concluded that in Brazil, vitamin A supplementation may have little benefit in reducing morbidity.