Serum Bone-Resorption Biomarkers: Correlation with Alveolar and Systemic Bone Changes

Objective: To examine the association between serum bone resorption biomarkers and alveolar and systemic bone loss. Methods: 128 postmenopausal osteopenic, estrogen-deficient women on periodontal maintenance therapy for moderate-advanced periodontitis participated in a two-year randomized, double-blind, placebo-controlled, clinical trial examining the efficacy/safety of subantimicrobial dose doxycycline (SDD; 20 mg bid). Posterior vertical bite-wings were taken at baseline, one and two years for alveolar bone density and height (ABD and ABH). ABD and systemic bone mineral density (BMD) were determined by computer-assisted densitometric image analysis (CADIA) and dual-energy x-ray absorptiometry, respectively. ABH was determined by the method of Hausmann et al. Serum type I collagen bone resorption markers, CTx (ELISA) and ICTP (RIA), also were measured. This abstract presents secondary analyses (using Generalized Estimating Equations) from this trial; namely, concurrent changes between serum biomarkers and alveolar and systemic bone loss at one and two years. Results: Increases in serum CTx were associated with ABD loss (p=0.01) regardless of treatment and time, while the association between serum ICTP and ABD loss was not significant (p=0.2). Regarding ABH, there was no significant association between serum CTx and ABH loss (p=0.9). However, increases in serum ICTP over two years were associated with ABH loss (p=0.005) regardless of treatment. Increases in serum CTx were associated with lumbar spine BMD loss at two years (p=0.001); this association was driven primarily by placebo subjects. The association between serum CTx and femoral BMD loss at two years was not significant (p=0.2). No significant association was found between serum ICTP and systemic BMD loss. Conclusions: These data suggest that, in this postmenopausal subject population, ABD and ABH loss, like systemic BMD, may reflect, in part, biomarkers of systemic bone turnover. Supported by NIDCR grant R01DE012872.