Objective: Although osteoporosis and atherosclerosis seem to be related, the mechanisms are not yet understood. We previously observed that women with higher serum concentrations of high sensitivity C-reactive protein (hsCRP), a strong risk factor for atherosclerosis, had lower bone mineral density (BMD). However, the relationship of hsCRP level with bone turnover rate, an independent risk factor for osteoporotic fracture, is not known.
Design: Cross-sectional hospital-based survey.
Patients: Apparently healthy pre- and postmenopausal women (n = 39 and 150, respectively).
Measurements: Urinary N-terminal telopeptide of type I collagen (NTx) and serum bone specific alkaline phosphatase (BALP) were measured using commercially available immunoassay kits. Serum hsCRP concentrations were measured by a particle-enhanced immunoturbidometric method.
Results: Both urinary NTx (gamma = 0.288, P < 0.001) and serum BALP (gamma = 0.260, P < 0.001) were positively correlated with serum hsCRP levels. Significance remained even after adjustment for age, body mass index and years since menopause (gamma = 0.257, P < 0.001, and gamma = 0.163, P = 0.027, respectively). Compared with subjects in the lowest hsCRP quartile (< or = 0.6 mg/l), those in the highest hsCRP quartile (> or = 1.6 mg/l) had significantly higher urinary NTx concentrations (P = 0.001) after adjustment for confounding variables. There was an increasing trend of serum BALP concentrations in the higher hsCRP quartile groups (P = 0.073).
Conclusion: These findings suggest that low grade systemic inflammation may be a common linking factor between development of atherosclerosis and increased bone turnover rate.