Vitamin D status and parathyroid hormone concentrations in Chinese women and men from north-east of the People's Republic of China

Study objective: To evaluate vitamin D status of young and old women and men living in Shenyang, north-east People's Republic of China in early spring and to explore the relationship between vitamin D metabolites and parathyroid hormone (PTH) in this population. Design: Cross-sectional study. Setting: Shenyang, north-east China. Subjects: 194 healthy volunteers: 38 young women and 48 young men aged 25-35 y, and 48 old women and 50 old men aged 65 - 75 y. Results: Fasting blood samples were used to measure plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)(2)D) and PTH using radioimmunoassays. The proportion of subjects who could be regarded as vitamin D deficient ( < 25 nmol/l) was 48%, 29%, 15% and 13% for old men, young men, old women and young women, respectively. There was no association between plasma 1.25(OH)(2)D and 25(OH)D concentrations. PTH concentrations were elevated in both old women and men compared with young subjects (P < 0.01). A negative association between PTH and 25(OH)D was only found in old women (P < 0.001), but not in old men, nor in young subjects. Conclusions: Vitamin D status was poor in this population in early spring, especially in men. There was no clear evidence to show that the secretion of PTH and the conversion of 1,25(OH)(2)D were affected by the low 25(OH)D concentration.