[The association between vitamin D and bone mineral density of urban postmenopausal women in Beijing].

OBJECTIVE: To study the association between vitamin D status and bone mineral density(BMD) in urban postmenopausal women in Beijing.

METHODS: A total of 400 community-dwelling women older than 60 (median age 67.8 years) were selected randomly from 17 community of 3 districts in Beijing by cluster sampling method from May to July, 2008. Serum 25(OH)D concentrations were measured by radioimmunoassay, using the DiaSorin kit, America. The objects were assigned into four groups: vitamin D deficient group (group A, 25(OH)D < 25 nmol/L), insufficient group(group B, 25 nmol/L < 25(OH)D < or = 50 nmol/L), normal group (group C, 50 nmol/L < 25(OH)D < or = 75 nmol/L) and enough group (group D, 25(OH)D > 75 nmol/L). The BMD at total, lumbar spine (L(2-4)) and proximal femur were measured by dual-energy X-ray absorptiometry (DEXA).

RESULTS: The mean concentration of serum 25(OH)D concentration was (36.0 +/- 14.6) nmol/L, BMD at total and proximal femur were respectively (0.829 +/- 0.090) and (0.679 +/- 0.106) g/cm(2). The mean BMD at total of group A, B, C + D were respectively (0.811 +/- 0.077), (0.825 +/- 0.088) and (0.864 +/- 0.112) g/cm(2)(F = 16.93, P < 0.01), and BMD at proximal femur of group A, B, C + D were respectively (0.666 +/- 0.107), (0.673 +/- 0.099) and (0.725 +/- 0.117) g/cm(2)(F = 18.36, P < 0.01). The 25(OH)D level was positively correlated with BMD at total body and proximal femur (r values were 0.17 and 0.18, both P values < 0.05).

CONCLUSION: Vitamin D status was highly correlated with BMD at lumbar spine (L(2-4)), proximal femur, pelvis and limbs for the postmenopausal older women.