Is There an Association between Vitamin D Concentrations and Overweight in Children and Adolescents?

Objective: To describe the 25-hydroxyvitamin D [25(OH)D] concentrations in children and adolescents and to verify the association with the body mass index z-score (ZBMI), lipid profile and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR).

Method: Cross-sectional study with 170 children and adolescents aged between 4 and 15 years (106 normal weight and 64 overweight) from a public institution in Santo André-Brazil. Weight, height and waist circumference were verified and ZBMI and waist-to-height ratio (WHtR) were calculated. Biochemical analysis: 25(OH)D levels [deficiency: 25(OH)D < 20 ng/ml]; glycemia and insulin (HOMA-IR), lipid profile and ultra-sensitive C-reactive protein.

Results: Mean age was 8.37 ± 3.17 years; 89 (52.4%) were male; 77 (45.3%) Caucasians and 121 (71.2%) pre-pubescent. Overweight was observed in 64 (37.6%), dyslipidemia in 108 (63.5%) and 25(OH)D deficiency in 117 (68.8%) of the individuals. ZBMI (r = -0.209; p = 0.006), WHtR (r = -0.154; p = 0.045), triglycerides (TGs) (r = -0.161; p = 0.037) and TGs/high-density lipoprotein (HDL) ratio (r = -0.168; p = 0.028) were inversely correlated with 25(OH)D concentrations. Overweight children and adolescents were four times more likely to have vitamin D deficiency (odds ratio = 4.28; 95% confidence interval 1.152 to 4.907; p = 0.019), after adjustment for pubertal development (prepubertal), sex (male), HDL-c (<45 mg/dl), non-HDL (>120 mg/dl), TG/HDL ratio (>2.0) and HOMA-IR.

Conclusions: A high prevalence of vitamin D deficiency (68.8%) was observed. There was an independent association between vitamin D deficiency and overweight, not observed for dyslipidemia and insulin resistance. The data point to the need for periodic monitoring of serum concentrations of 25(OH)D and reinforcement of guidelines for combating and preventing overweight in the pediatric age group.