OBJECTIVES: The therapeutic potential of vitamin D has been studied regarding adjuvant interventions. Some studies have evaluated the factors associated with vitamin D deficiency (VDD) in healthy populations, but they are scarce in children and adolescents with type 1 diabetes mellitus (T1DM). The objective of this study was to describe the prevalence of and factors associated with VDD in children and adolescents with T1DM. METHODS: This was a cross-sectional analysis of the baseline data from a controlled clinical trial. Participants were between 7 and 16 y old, diagnosed with T1DM for at least 1 y, and classified as having VDD when 25-hydroxyvitamin D (25[OH]D) was less than 30 ng/mL. The following data were collected: sociodemographic, clinical, laboratory, lifestyle, anthropometric, and Fok-I polymorphism (rs2228570). A multivariable logistic regression model was developed to adjust the effect of potential confounders. The odds ratio (OR) with 95% confidence interval (CI) was used. The significance level used was 5%. RESULTS: A total of 143 children and adolescents were enrolled
51% were female and the mean age was 11.5 ± 2.2 y old. The prevalence of VDD was 79% and the mean 25(OH)D of participants with VDD was 19.2 ± 6.1 ng/mL. The factors associated with VDD were low level of physical activity (OR, 2.9, 95% CI, 1.1-7.6, P = 0.031), poor glycemic control (OR, 5.0, 95% CI, 1.9-13.2, P = 0.001), and excess weight (OR, 3.6, 95% CI, 1.1-11.1, P = 0.029). CONCLUSIONS: A high prevalence of VDD was observed as well as some associated lifestyle and clinical variables. Recommendations for children and adolescents with T1DM include monitoring their 25(OH)D and encouraging healthy eating practices and routine physical exercise.