Levels of serum sclerostin, FGF-23, and intact parathyroid hormone in postmenopausal women treated with calcitriol.

Objective: This study aimed to determine the effect of calcitriol on serum concentrations of fibroblast growth factor-23 (FGF-23), sclerostin, intact parathyroid hormone (PTH), and handgrip strength in postmenopausal women with low bone mass.

Methods: A randomized, double-blind controlled trial was carried out among 141 postmenopausal women with low bone mass. Participants were randomized into two groups: 75 participants received calcitriol 0.5 µg/day and 66 participants received a placebo for 12 weeks.

Results: After 12-week calcitriol treatment, significant decreases in serum intact PTH ( P =0.035) and sclerostin ( P =0.039), as well as significant increases in serum creatinine ( P =0.027), uric acid ( P =0.032), 24-hour urinary calcium ( P =0.0026), and left handgrip strength ( P =0.03), were observed, compared to placebo group. Level of serum sclerostin was weakly but significantly positively correlated with serum PTH ( r =0.277; P =0.01) and negatively correlated with 24-hour urinary calcium ( r =-0.221; P =0.04) and left handgrip strength ( r =-0.338; P =0.03) after calcitriol treatment. Multiple regression analysis demonstrated that decrease in serum sclerostin was associated with decrease in PTH serum level after calcitriol treatment (OR, 7.90; 95% CI, 2.28-27.42; P =0.002). However, no significant change in FGF-23 level was observed after calcitriol treatment.

Conclusion: Calcitriol treatment yields a considerable decrease in serum sclerostin and significant increase of handgrip strength, and the change in serum sclerostin is regulated by serum PTH and by muscle strength.