Adult serum 25(OH)D3 in Gansu province, northwest China: a cross-sectional study.

Background And Objectives: This analytical cross-sectional study investigated the prevalence of vitamin D deficiency and its association with metabolic risk factors in the adult population of Gansu Province, China.

Methods And Study Design: In total, 11,157 healthy participants (4,740 men and 6,417 women) were enrolled. A questionnaire was used to assess general characteristics and personal habits. We detected 25-hydroxyvitamin D and associated metabolic parameters through electrochemiluminescence immunoassays.

Results: The prevalence of severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (>=30 ng/mL) among the participants was 17.3%, 64.6%, 11.8%, and 6.3%, respectively. Vitamin D deficiency was more prevalent in women than in men (82.5% vs 81.1%, p<0.001). The significant predictors of vitamin D deficiency included younger age and female sex (p<0.05), whereas sun exposure, physical activity, and calcium (Ca) supplementation were associated with less vitamin D deficiency (p<0.05). Serum 25(OH)D3 was inversely associated with parathyroid hormone (r=-0.279, p<0.001) and positively associated with serum Ca (r=0.239, p<0.001), serum P (r=0.090, p=0.018), LDL cholesterol (r=0.100, p=0.008), and BMI (r=0.093, p=0.014). No significant association was observed between serum 25(OH)D3 and metabolic disorders.

Conclusions: Vitamin D deficiency is highly prevalent among the adult population of Gansu Province, northwest China, especially young physically inactive and overweight women with limited sunlight exposure, whose biomarkers put them at greater risk of osteoporosis and cardiovascular disease.