Evaluation of serum levels of 25-hydroxyvitamin D in overweight adolescents

Abstract

OBJECTIVE: To evaluate serum levels of 25-hydroxyvitamin D [25(OH)D] in overweight adolescents. METHODS: Observational study with 86 overweight adolescents followed during secondary care service between August 2014 and August 2016. For the diagnosis of overweight, the criteria of the World Health Organization were considered. Serum levels of 25(OH)D were categorized as: sufficiency (≥ 30 ng/mL), insufficiency (between 20 and 29 ng/mL) and deficiency (< 20 ng/mL). The categories of vitamin D deficiency and insufficiency were grouped into the hypovitaminosis D category in some analyses. RESULTS: Only 38.4% of adolescents had vitamin D levels above the recommended level, 23.2% had insufficient levels and 38.4% had deficient levels. There was a higher frequency of hypovitaminosis D (71.4% versus 52.3%; p = 0.03) and lower serum levels of 25(OH)D (23.9 ± 8.7 ng/mL versus 28.1 ± 10.6; p < 0.05) in obese adolescents compared to overweight adolescents. There was no difference in 25(OH)D levels between sex and age categories. CONCLUSIONS: Hypovitaminosis D occurred in 61% of adolescents and was positively associated with obesity. An inverse relationship was observed between serum 25(OH)D levels and the degree of overweight.