Differences of therapeutic effects on regional bone mineral density and markers of bone mineral metabolism between alendronate and alfacalcidol in Japanese osteoporotic women

We studied the differences of therapeutic effects on regional bone mineral density (BMD) and markers of bone mineral metabolism between alendronate and alfacalcidol in Japanese osteoporotic women. Ninety-two Japanese women suffering from primary osteoporosis without osteoporotic fractures, aged 55 to 81 years, were divided into two groups : women treated orally with alendronate for one-year (5mg/day)(alendronate group, n=35) and women treated orally with alfacalcidol for one year (0.5μg/ day) (alfacalcidol group, n=57). The mean BMD of the 2nd to 4th lumbar vertebrae (L2-4 BMD) and regional BMD were measured using dual energy X-ray absorptiometry. In the alendronate group, the percentage changes of L2-4BMD, lumbar spine BMD, thoracic spine BMD, pelvis BMD in the alendronate group were 106.3±4.6%, 104.2±6.6%, 107.1± 10.4%, 107.1±10.5%, respectively. The percentage changes of L2-4BMD and regional BMD except for head BMD in the alendronate group were significantly greater than those in the alfacalcidol group. In the alfacalcidol group, L2-4BMD, thoracic spine BMD and lumbar spine BMD were maintained at respective pretreatment levels, whereas other regional BMD were decreased. Both serum bone-specific alkaline phosphatase and urinary type I collagen cross-linked N-telopeptide of the alendronate group were decreased, whereas these markers of bone mineral metabolism of alfacalcidol group were increased compared with the respective pre-treatment levels. The results suggest that one-year treatment with alendronate increased L2-4BMD, lumbar spine BMD, thoracic spine BMD and pelvis BMD, and that markers of both bone formation and bone resorption were decreased following one-year treatment with alendronate.