Declining serum bone turnover markers are associated with the short-term positive change of lumbar spine bone mineral density in postmenopausal women

Abstract

Objective: While serum bone turnover markers (BTMs) and bone mineral density (BMD) have been confirmed as useable risk assessment tools for postmenopausal osteoporosis, the associations between BTMs and BMD changes are still ambiguous. The aim of this study was to explore the underlying associations between BTMs and BMD changes in postmenopausal women.

Methods: Between January 2015 and October 2020, 135 postmenopausal women were retrospectively enrolled. They were divided into two groups according to lumbar spine (LS) 1-4 BMD change (1 y T-score minus baseline T-score, Group 1 [n = 36] < 0 and Group 2 [n = 99] ≥ 0). The changes of BTMs (N-terminal middle segment osteocalcin [N-MID], propeptide of type I procollagen [P1NP], and β-C-terminal telopeptide of type I collagen [β-CTX]) and their associations with LS 1-4 BMD change were analyzed. The biochemical indices and clinical parameters related with LS 1-4 BMD change were also evaluated.

Results: The 1 year N-MID, P1NP, β-CTX and Phosphorus in Group 2 were lower than those in Group 1 (P < 0.05), their changes within 1 year were significantly negatively correlated with LS 1-4 BMD change (R2 = -0.200, P < 0.001; R2 = -0.230, P < 0.001; R2 = -0.186, P < 0.001; R2 = -0.044, P = 0.015; respectively). Except for the Phosphorus change (area under the curve [AUC] = 0.623), the changes of N-MID, P1NP, and β-CTX and their 1 year levels had similar AUC to diagnose the short-term LS 1-4 BMD change (AUC > 0.7 for all, with the AUC of 1 y P1NP being the largest at 0.803). Binary logistic regression analysis showed that the physical activity and drug intervention were the determinant factors for the LS 1-4 BMD change (odds ratio = 6.856, 95% confidence interval: 2.058-22.839, P = 0.002; odds ratio = 5.114, 95% confidence interval: 1.551-16.864, P = 0.007; respectively).

Conclusions: Declining N-MID, P1NP, β-CTX, and Phosphorus are associated with the short-term increase of LS 1-4 BMD within 1 year. Physical activity and drug intervention are factors significantly influencing the change of LS 1-4 BMD in postmenopausal women.

FIG. 1

The constituent ratios of different drug interventions in the two groups. Nt, no treatment; Bd, basic drugs (calcium carbonate and vitamin D3 tablets + calcitriol soft capsules); Ale, alendronate sodium and vitamin D3 tablets; Bd + Ale, alendronate sodium and vitamin D3 tablets + basic drugs; Zol, zoledronic acid injection; Bd + Zol, zoledronic acid injection + basic drugs.

FIG. 2

Comparison of the differences in N-MID, P1NP, β-CTX, Phosphorus, and BMD at 1 year follow-up between the two groups. All P values were calculated with the t test. ns, not significant. ^∗P < 0.05. ^∗∗P < 0.01. β-CTX, β-C-terminal telopeptide of type I collagen; BMD, bone mineral density; FN, femoral neck; LS, lumbar spine; N-MID, N-terminal middle segment osteocalcin; P1NP, propeptide of type I procollagen; TH, total hip.