Low vitamin D concentrations among indigenous Argentinean children living at high altitudes

Hypovitaminosis D is an international problem; however, there is little information about its prevalence in apparently healthy Indian children living at high altitudes.

To determine (i) the prevalence of hypovitaminosis D and (ii) the association of serum vitamin D with the risk factors for diabetes among Indian Koya children.

A cross-sectional study of 290 (129 males) school children aged 10.7 ± 2.9 yr was performed. Anthropometric measures, blood pressure (BP), Tanner stages and serum levels of glucose, lipids, and insulin were measured. 25-hydroxyvitamin D [25(OH)D] was measured by radioimmunoassay (Dia Sorin).

The prevalence of obesity was 3.4% (10), overweight 3.4% (10), normal weight 79.0% (229), and underweight 14.1 % (41) per CDC reference standards. Concentrations of [25(OH)D] were median 10 (range 8-13 ng/mL); 10 (3.4%) had insufficient vitamin D levels (20 to <30 ng/mL), 136 (46.9%) had deficient levels (10 to <20 ng/mL), 144 (49.7%) had severe deficiency (<10 ng/mL) and none had optimal levels (≥30 ng/mL). There was an inverse significant correlation between [25(OH)D] and age (r = 0.14), body mass index (BMI) (r = 0.16), waist circumference (r = 0.15), systolic BP (r = 0.19), hemoglobin (r = 0.19), glucose (r = 0.22), insulin (r = 0.13), and homeostasis model of assessment-insulin resistance (r = 0.16). Multiple linear regression analysis showed that 25(OH)D concentrations were significantly and inversely associated with glucose concentrations (β = -0.28; p = 0.02) adjusted for age, BMI, systolic BP, hemoglobin, and insulin.

This study demonstrated a high prevalence of both 25(OH)D deficiency and insufficiency and an inverse association between 25(OH)D and glucose concentration in apparently healthy Koya Indian children. Further research is needed to confirm these findings.