The levels of bone turnover markers 25(OH)D and PTH and their relationship with bone mineral density in postmenopausal women in a suburban district in China

Abstract

The aims of this study were to evaluate the levels of bone turnover markers (BTMs), including serum N-terminal procollagen of type I collagen (P1NP), beta C-terminal cross-linked of type I collagen (β-CTX), 25-hydroxyvitamin D [25(OH)D], and parathyroid hormone (PTH), and to investigate relationships between these markers and bone mineral density (BMD) as well the prevalence of osteoporosis in postmenopausal women of suburban district. A population of 4822 postmenopausal women aged 55-69years old (62.22 ± 6.75) from the suburban district was recruited voluntarily. BMD was measured at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry; 2251 women in this group had the serum BTMs 25(OH)D and PTH tested. The prevalence of osteoporosis was 25.03% at lumbar spine and 6.23% at femoral neck. The median (interquartile range) values of serum P1NP, β-CTX, 25(OH)D, and PTH were 59.3ng/mL (44.7-75.52), 0.370ng/mL (0.280-0.490), 23.0ng/mL (17.1-30.5), and 31.4pg/mL (24.9-39.7), respectively. Serum P1NP and β-CTX levels presented significantly negative correlations with BMDs at the all the sites (Betastd = -0.098 to -0.208, respectively, P < 0.001), whereas PTH levels were negatively correlated with BMDs of the femoral neck and total hip (Betastd = -0.062 and -0.054, P < 0.01, respectively). Serum 25(OH)D had positive associations with BMDs at total hip (Betastd = 0.051, P < 0.01). The BMD of postmenopausal women in China suburban area is higher than that in downtown area, and over 60% of the participants had their serum 25(OH)D level over 20ng/mL. BTMs were negatively correlated with BMDs, suggesting that BTMs are reliable factors for early declines in BMD.