Prevalence and predictors of vitamin D insufficiency in Brazilian children under 5 years of age: Brazilian National Survey on Child Nutrition (ENANI-2019).

To analyze the association of sociodemographic and health factors with vitamin D insufficiency and 25(OH)D concentration in Brazilian children aged 6-59 months. Data from 8,145 children from the Brazilian National Survey on Child Nutrition (ENANI-2019) were analyzed. The serum concentration of 25(OHD)D was measured using a chemiluminescent immunoassay. The prevalence of vitamin D insufficiency [25(OHD)D <50 nmol/L] and 95% confidence intervals (95%CI) were calculated. Logistic and linear regression models were used to identify the variables associated with vitamin D insufficiency and serum 25(OH)D concentrations, respectively. The mean 25(OH)D concentration was 98.6±36.0 nmol/L, and 4.3% of the children presented vitamin D insufficiency. Children aged 6-23 months (OR= 2.23; 95%CI 1.52, 3.26); belonging to Southeast (OR= 5.55; 95%CI 2.34, 13.17) and South (OR= 4.57; 95%CI 1.77, 11.84) regions; the second tertile of the National Wealth Score (OR= 2.14; 95%CI 1.16, 3.91); and winter (OR= 5.82; 95%CI 2.67, 12.71) and spring (OR= 4.84; 95%CI 2.17, 10.80) seasons of blood collection were associated with a higher chance of vitamin D insufficiency. Female sex (β= -5.66, 95%CI -7.81, -3.51), urban location (β= -14.19, 95%CI -21.0, -7.22), and no vitamin D supplement use (β= -6.01, 95%CI -9.64, -2.39) were inversely associated with serum 25(OH)D concentration. The age of children and the Brazilian geographical region of household location were the main predictors of vitamin D insufficiency. In Brazil, vitamin D insufficiency among children aged 6-59 months is low and is not a relevant public health problem.