Benefit period using alendronate to increase bone mineral density in women with osteoporosis?

Alendronate, a nitrogen-containing bisphosphonate is a specific inhibitor of bone resorption and now in the forefront of treatment of osteoporosis. In this study, we reported a significant increase in bone mineral density (BMD) of the spine and the hip in postmenopausal women taking alendronate at 10 mg/d for 1, 2 and 3 years.

Participants had received daily, oral, 10 mg dose of alendronate for one to three years and placed into one of three groups according to alendronate treatment duration: 41 women received alendronate for 1 year (group I), 46 received alendronate for 2 years (group II), and 30 received alendronate for 3 years (group III). Measurements of bone density had been made by dual energy X-ray absorbtiometry once each year.

The differences in L2-L4, L2, L4, femoral neck and trochanter BMD values before and after treatment for first group were significantly different. In second group, significant differences between initial and after treatment were found at the other sites except at the Ward's triangle. In the third group, only a significant increase in the L2-L4, L2, L3, L4, trochanter BMD values between before treatment and at the end of third year was found. Comparisons between groups were performed with Student's t test. ANOVA was used to test the age, menopause age, menopause duration and initial BMD values between the three groups. Calculated P values of less than 0.05 were considered statistically significant.

Alendronate had increased BMD significantly at the spine and hip in postmenopausal women over three years. Increases of BMD in third group were significant during the first and second years. However, continued therapy with alendronate had been required to maintain the gain in BMD over the third year.