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

To analyse the association of socio-demographic and health factors with vitamin D insufficiency and 25-hydroxyvitamin D (25(OH)D) concentration in Brazilian children aged 6-59 months. Data from 8145 children from the Brazilian National Survey on Child Nutrition (ENANI-2019) were analysed. The serum concentration of 25(OHD)D was measured using a chemiluminescent immunoassay. The prevalence of vitamin D insufficiency (25(OH)D < 50 nmol/l) and 95 % CI was 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 center dot 6 +/- 36 center dot 0 nmol/l, and 4 center dot 3 % of the children presented vitamin D insufficiency. Children aged 6-23 months (OR = 2 center dot 23; 95 % CI 1 center dot 52, 3 center dot 26); belonging to Southeast (OR = 5 center dot 55; 95 % CI 2 center dot 34, 13 center dot 17) and South (OR = 4 center dot 57; 95 % CI 1 center dot 77, 11 center dot 84) regions; the second tertile of the National Wealth Score (OR = 2 center dot 14; 95 % CI 1 center dot 16, 3 center dot 91) and winter (OR = 5 center dot 82; 95 % CI 2 center dot 67, 12 center dot 71) and spring (OR = 4 center dot 84; 95 % CI 2 center dot 17, 10 center dot 80) seasons of blood collection were associated with a higher chance of vitamin D insufficiency. Female sex (beta = -5 center dot 66, 95 % CI - 7 center dot 81, -3 center dot 51), urban location (beta = -14 center dot 19, 95 % CI -21 center dot 0, -7 center dot 22) and no vitamin D supplement use (beta = -6 center dot 01, 95 % CI -9 center dot 64, -2 center dot 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.