Association of vitamin D with insulin resistance in Argentine boys: A pilot study

Abstract

Hypovitaminosis D has been associated with insulin resistance. The objectives of the study was to the prevalence of hypovitaminosis D, and the association of vitamin D concentrations with age, Tanner stage, BMI and insulin sensitivity (HOMA-IR) in a group of healthy boys. Data were collected cross-sectionally at an amateur rugby club in the Buenos Aires suburbs in May, 2010. BMI, waist circumference, Tanner staging, blood pressure, and levels of glucose, lipids, and insulin were determined. 25-hydroxyvitamin D [25(OH)D] was measured by radioimmunoassay. One hundred and sixteen boys aged 11.3 ± 2.4 y were examined; 19 (16.4%) and 40 (34.5%) boys were overweight and obese, respectively, per United States Centers for Disease Control and Prevention. 52.2% of the children were at Tanner 1. Serum concentration of [25(OH)D] had a median value of 20 ng/mL (interquartile range 18–21 ng/mL). Sixty (52.6%) boys had insufficient [25(OH)D] ([25(OH)D > 20 but ≤ 30 ng/mL), and 54 (46.6%) had deficient levels ([25(OH)D] < 20 ng/mL). Univariate analyses indicated a negative significant association between [25(OH)D] and BMI (r −0.20, P = 0.03), waist circumference (r −0.23, P = 0.01), HOMA-IR (r −0.25, P = 0.007), and insulin (r −0.29, P = 0.002). Multiple regression analysis showed that [25(OH)D] concentration was significantly and inversely associated with HOMA-IR, (B = −0.8; p = 0.02) adjusted for Tanner and BMI (R² = 0.35). This study demonstrated an inverse association between [25(OH)D] and HOMA-IR in healthy boys adjusted for pubertal development and BMI. It also showed a high prevalence of both [25(OH)D] deficiency and insufficiency. Further research is needed on the prospective association between vitamin D and the risk for type 2 diabetes.

Keywords

Vitamin D - insulin resistance - boys