Although most of those studies involved only a small number of subjects, some studies demonstrated that alfacalcidol treatment resulted in a significant reduction [8] and [9], while others did not show a significant reduction [10] and [11], Enzalutamide mouse in vertebral fracture incidence compared with a placebo. However, the effect of eldecalcitol has not been compared head-to-head with that of alfacalcidol. An open-label clinical trial to compare the effect of eldecalcitol with that of alfacalcidol on bone turnover and calcium (Ca) metabolism showed that 0.5 to 1.0 μg/day eldecalcitol inhibits bone resorption more than alfacalcidol, while their

effects on bone formation markers and urinary Ca excretion were similar [12]. The present study was conducted to compare the effect of eldecalcitol with that

of alfacalcidol in preventing vertebral fractures in men and women with osteoporosis. This was a randomized, active comparator, double-blind, superiority trial of the effect of eldecalcitol versus alfacalcidol for reduction in incidence of vertebral fractures. A total of 1054 patients (1030 females and 24 males, all Japanese) aged from 46 to 92 years (mean 72.1 years) from 52 centers in Japan were selleck enrolled between September 2004 and August 2005, and randomly assigned to receive identical capsules of either 0.75 μg eldecalcitol or 1.0 μg alfacalcidol once a day for 36 months. Adherence to the medications was monitored by counting the remaining capsules at each visit, and was more than 95% in average throughout the study period (96.5% in eldecalcitol and 95.7% in alfacalcidol groups, respectively).

Serum 25(OH)D measured by Nichols Allegro Lite (Nichols Institute, San Clemente, CA) was below 50 nmol/L in 39.3% of the patients at enrollment (208 in eldecalcitol and 206 in alfacalcidol group). These patients were given 400 IU/day vitamin D3 throughout the study period. Patients without vertebral fractures were enrolled if their lumbar spine or total hip BMD T-score was below − 2.6 and they were 70 years or older, or if their T-score was below − 3.4 and they were younger than 70 years. Patients with lumbar spine or total hip BMD T-score of below − 1.7 were enrolled if they had between one and Calpain five vertebral fractures. Prevalent vertebral fractures at enrollment were assessed by lateral spine X-ray examination of the thoracic and lumbar vertebrae, and were diagnosed quantitatively according to the criteria of the Japanese Society for Bone and Mineral Research [13] and [14]. Women were at least 3 years after menopause or older than 60 years. Patients were excluded if they had primary hyperparathyroidism, Cushing’s syndrome, premature menopause due to hypothalamic, pituitary or gonadal insufficiency, poorly controlled diabetes mellitus (HbA1c over 9%) or other causes of secondary osteoporosis, or had a history of urolithiasis.