Nasal salmon calcitonin blunts bone microstructure alterations in healthy postmenopausal women

Abstract

In healthy postmenopausal women, nasal salmon calcitonin blunted distal radius and tibia bone microstructure degradation.

Introduction: Nasal salmon calcitonin (NSC) has been reported to lower vertebral fracture risk by 33%, but to modestly increase spine areal bone mineral density (aBMD) by 1.5%. Thus, NSC may also influence bone microstructure, another known determinant of bone strength.

Methods: In a randomized, double-blind, placebo-controlled trial, we investigated the effects of 200 IU/day NSC on distal radius and tibia bone microstructure (by high-resolution 3-dimensional peripheral quantitative computerized tomography), aBMD (by dual-energy X-ray absorptiometry), and serum bone turnover markers in healthy postmenopausal women.

Results: Mean age was 57.6 ± 0.8 (±SEM) and 57.4 ± 0.7 in NSC (n = 45) and placebo groups (n = 45), respectively. Mean femoral neck T-score was in the osteopenic range; prevalent vertebral fracture was 4% in each group. There was no observed between-group difference in the primary outcome distal radius BV/TV (-2.8 ± 0.6% vs. -4.3 ± 1.0%, NS). By 2 years, the decrease in distal radius total density vs. baseline was 4.4 ± 0.7% in controls and 2.1 ± 0.6% in NSC-receiving patients (p < 0.05). Distal radius and tibia cortical thickness decreased by 3.7 ± 1.0 and 2.4 ± 0.5% in placebo (p < 0.05 vs. baseline for both), respectively, but not in the NSC group. Distal radius total density and cortical thickness changes were lower in NSC group than in placebo (p < 0.05 for both) in the subgroup with baseline C-terminal telopeptides (CTX) above the median. By 6 and 12 months, serum CTX decreased by 17.3 ± 6.2 and 19.1 ± 6.6% (both p < 0.05 vs. baseline), respectively, in NSC, but remained stable in controls (NS vs. baseline). There was no difference in aBMD. NSC was well tolerated, with less arthralgia than the placebo group (14 vs. 26, p < 0.05).

Conclusion: Nasal salmon calcitonin blunted the degradation of distal radius and tibia bone microstructure in healthy postmenopausal women.