Vitamin D Status and Indices of Bone Turnover in Older European Adults

Abstract

An increased rate of bone turnover increases risk of osteoporotic fracture later in life. The concentration of 25-hydroxyvitamin D that contributes to an elevated rate of bone turnover in older adults is unclear. The objective of this study was to investigate the associations between 25-hydroxyvitamin D and biochemical markers of bone turnover in an older, pan-European cohort. 25-hydroxyvitamin D and serum markers of bone-formation (osteocalcin and bone-specific alkaline phosphatase) were assessed by ELISA, while urinary markers of bone-resorption (pyridinoline and deoxypyridinoline) were assessed by HPLC. Six percent, 36 %, and 64 % of subjects had 25-hydroxyvitamin D concentrations ≤ 25, ≤ 50, and ≤ 80 nmol/L throughout the year, respectively. 25-hydroxyvitamin D was significantly and inversely correlated with serum bone-specific alkaline phosphatase (r = 0.119; p = 0.022) and urinary pyridinoline (r = 0.207; p ≤ 0.0001) and deoxypyridinoline (r = 0.230; p ≤ 0.0001). Stratification on the basis of tertiles [T] of 25-hydroxyvitamin D (≤ 47.6 [T 1 ]; 47.6-85.8 [T 2 ]; ≥ 85.8 [T 3 ] nmol/L), showed that urinary pyridinoline and deoxypyridinoline were significantly lower in subjects in the 2 nd and 3 rd compared to the 1 st tertile (p ≤ 0.015). Low vitamin D status (≤ 50 nmol/L) was associated with an increased rate of bone turnover in this older pan-European cohort. © 2011 Hans Huber Publishers, Hogrefe AG, Bern.