Serum levels of the bone turnover markers dickkopf-1, sclerostin, osteoprotegerin, osteopontin, osteocalcin and 25-hydroxyvitamin D in Swedish geriatric patients aged 75 years or older with a fresh hip fracture and in healthy controls

Background Bone turnover markers have a potential clinical use in describing bone remodeling and in predicting fractures. Aims In an elderly population >= 75 years with a fresh hip fracture, and in healthy controls, investigate bone turnover markers and their relation to each other, to vitamin D status and to bone mineral density (BMD). Methods In a cross-sectional study serum levels of dick-kopf-1 (DKK-1), sclerostin (SOST), osteoprotegerin (OPG), osteopontin (OPN), osteocalcin, 25-hydroxyvitamin D (25(OH) D) were analyzed in 89 Swedish patients with a fresh hip fracture and in 82 healthy volunteers. Serum levels of bone markers were determined by Luminex technique. Results S-25-hydroxyvitamin D (S-25(OH) D) was decreased in patients compared to controls (48 +/- 21 vs. 76 +/- 25 nmol/L, p < 0.001). SOST, but none of the other bone turnover markers correlated with BMD (r = 0.50, p < 0.001). Compared with controls, higher levels of OPG (488 +/- 1.4 vs. 191 +/- 1.4 ng/L, p < 0.001), OPN (69 +/- 1.7 vs. 19 +/- 1.4 mu g/L, p < 0.001), DKK-1 (273 +/- 1.7 vs. 168 +/- 1.7 ng/L, p < 0.001), and lower levels of osteocalcin (5.8 +/- 3.5 vs. 9.5 +/- 3.6 mu g/L, p < 0.001), were found in the fracture group. Levels of OPG, DKK-1 and SOST in both groups were positively associated. S-25(OH) D concentration was not found to be strongly associated with any of the bone markers. Conclusions In contrast to findings in other studies, we found no strong correlation between 25(OH) D and the investigated bone markers. Both in patients with a fresh hip fracture and in healthy elderly, DKK-1, SOST and OPG appear to be associated. This suggests a relevance in these relationships meriting further investigation.