Associação entre a prevalência de asma e níveis séricos de vitamina D em adolescentes brasileiros

Abstract

Objective: To evaluate the association between the prevalence of asthma and serum levels of vitamin D in Brazilian adolescents. Methods: Cross-sectional, school-based study involving adolescents aged 12 to 17 years from four large Brazilian cities located at different latitudes (Fortaleza, Rio de Janeiro, Brasília, and Porto Alegre). Information on asthma, lifestyle and sociodemographic characteristics was collected through self-administered questionnaires. Serum concentrations of 25(OH)D were classified for dichotomous analysis as sufficient (≥20 ng/mL) and insufficient/deficient (<20 ng/mL) levels. Bivariate analyzes between vitamin D levels and prevalence of active asthma (AA) and the other study variables were carried out, using the chi-squared test. Then, generalized linear models were configured to analyze potential confounding factors in the associations found (p <0.20). Results: Between the years 2013-14, 1,053 adolescents, were evaluated. Prevalence of AA and insufficient/deficient levels of 25(OH)D in the sample was 15.4% and 21% respectively. There were no statistically significant associations between active asthma and hypovitaminosis D. The comparison between the prevalence of active asthma and vitamin D levels between Rio de Janeiro and Porto Alegre, showed a prevalence of asthma and vitamin D insufficiency, respectively of 2.34 (95% CI: 1,28-4.30) and 3.22 (95%CI: 1.75-5.95) times higher in Porto Alegre, regardless of possible confounding factors. However, analysis of the association between the respective prevalence of active asthma and the vitamin D variables in each of cities evaluated did not reveal any significant associations. Conclusions: No association was observed between asthma and low levels of vitamin D in adolescents from different latitudes in Brazil