Bone turnover markers in Spanish postmenopausal women: the Camargo cohort study.

BACKGROUND: This cross-sectional study was performed to determine the reference ranges for two bone turnover markers--aminoterminal propeptide of type I collagen (P1NP) and C-terminal telopeptide of type I collagen (beta-CrossLaps, beta-CTX)--in normal postmenopausal Spanish women as determined in serum by automated methods.

METHODS: A community-based population of 1080 healthy postmenopausal women was evaluated. Data regarding risk factors for osteoporosis and fractures were collected by means of a structured questionnaire. Fasting serum levels of P1NP, beta-CTX, 25-Hydroxivitamin D (25OHD), and intact parathyroid hormone (iPTH) were measured on the Elecsys 2010 automated analyzer (Roche). BMD at lumbar spine, femoral neck and total hip was determined by DXA.

RESULTS: The mean age of subjects was 63+/-9. Logarithmic transformation of both markers was performed to allow for normal distributions. Mid-95% ranges for P1NP and beta-CTX were 19-100 ng/ml and 0.112-1.018 ng/ml, respectively. Mean values of P1NP (47.7+/-19.9 ng/ml) were similar to those previously determined by the manufacturer of the assays, whereas beta-CTX mean values (0.387+/-0.197 ng/ml) were lower. Both markers were higher among osteoporotic women.

CONCLUSIONS: Values obtained from this well-characterized population study provide reference ranges for serum automated P1NP and beta-CTX in normal Spanish postmenopausal women.