Vitamin D deficiency and associated factors in adolescent girls in Beijing

Abstract

Background: Several locally published reports indicate a high prevalence of vitamin D deficiency among adolescents in China, but no systematic population-based survey has been conducted. Objective: The objective was to determine the prevalence of vitamin D deficiency and to study associated factors in adolescent girls in Beijing. Design: A cross-sectional study was conducted in a random sample of 1248 Beijing girls aged 12–14 y. Nutrient intakes, ultraviolet light exposure, anthropometric characteristics, physical activity, signs and symptoms of rickets, and plasma concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and calcium were measured and X-rays of the hand and wrist were taken. Results: The prevalence of clinical vitamin D and calcium deficiency (plasma 25-hydroxyvitamin D P < 0.0005). Logistic regression analysis showed that subclinical and clinical vitamin D deficiency in winter were associated with low plasma 25-hydroxyvitamin D concentrations (x̄ ± SD: 280 ± 48 compared with 440 ± 61 mg/d), and low plasma calcium concentrations (Conclusions: Subclinical vitamin D deficiency was widespread among Beijing adolescent girls in winter. Low plasma 25-hydroxyvitamin D concentrations in summer, low calcium intake, and low plasma calcium concentrations in winter were the main risk factors for vitamin D deficiency in winter.