Establishing a reference range for bone turnover markers in young, healthy women

Introduction: Biochemical markers of bone turnover (BTMs) are important in determining fracture risk in postmenopausal women; high levels being associated with increased risk. A proposed goal of anti-resorptive therapy is to reduce BTMs to the lower half of the reference range for healthy young pre-menopausal women. Our aims were a) to establish reference ranges for bone alkaline phosphatase (bone ALP), crosslinked C- and N-telopeptides of type 1 collagen (beta CTX, NTX), osteocalcin (OC) and procollagen type I N propeptide (PINP) in pre-menopausal women and b) to investigate the determinants of these BTMs. Methods: BTMs were measured in peripheral blood and second morning void urine collected from 200 healthy pre-menopausal women ages 30 to 45 years. Each subject completed a short medical and lifestyle questionnaire. Results: BTMs were higher before the age of 35 years than after it. BTMs were higher in women with low BMI ( beta CTX and OC), low alcohol consumption (PINP), current smoking habit (bone ALP and NTX), and around time of ovulation (NTX). Conclusions: We recommend that the age range 35 to 45 years should be used when establishing BTM reference ranges in women. (c) 2008 Elsevier Inc. All rights reserved.