To investigate the prevalence of vitamin D deficiency and its associated metabolic risk factors in the healthy adults in Gansu Province, a western province of China.

Through stratified, multistage probability population sampling, 11 300 adults (4 740 men and 6 417 women aged 18-79 years) who had been living in their current residence for at least 5 years were arbitrarily chosen from seven representative geographical cities in Gansu Province from June 2014 to December 2015. The data obtained from a questionnaire-based survey, anthropometric and biochemical assessments, and areal bone mineral density measurement were collected and analyzed.

The overall mean serum 25(OH)D was (16.07±9.40) μg/L. The prevalence of severe deficiency (<10 μg/L), deficiency (≥10 μg/L and <20 μg/L), insufficiency (≥20 μg/Land <30 μg/L), and sufficiency (≥30 μg/L) among these adults were 17.3%, 64.6%, 11.8%, and 6.3%, respectively. The significant predictors of vitamin D deficiency included younger age and female sex(P<0.05), whereas sun exposure, physical activity, and calcium supplementation were protective (P<0.05). Serum 25(OH)D was inversely associated with parathyroid hormone (r=-0.279, P<0.001) and positively associated with serum calcium (r= 0.239, P<0.001), serum phosphorus (r=0.090, P=0.018), low-density lipoprotein cholesterol(r=0.100, P=0.008), and body mass index (r=0.093, P=0.014). The 25(OH)D concentration showed no significant correlation with bone mineral density (P>0.05).

Vitamin D deficiency is highly prevalent among adult populations in Gansu, northwestern of China, and is largely attributed to younger age and female sex. The cumulative effects of factors including sun exposure, physical activity, and calcium supplementation play an influential role in maintaining vitamin D levels.

Hydroxycholecalciferols; Vitamin D deficiency; Adult