Alendronate prevents postmenopausal bone loss in women without osteoporosis. A double-blind, randomized, controlled trial. Alendronate Osteoporosis Prevention Study Group.
Preventing bone loss associated with menopause and aging and maintaining the normal micro-architecture of bone provide important opportunities for the prevention of osteoporosis and fractures. To determine the safety and efficacy of alendronate, an aminobisphosphonate, for preventing postmenopausal bone loss. 3-year double-blind, randomized, placebo-controlled trial. 15 osteoporosis centers throughout the world. 447 women who had recently experienced menopause (6 to 36 months before study entry). Participants were randomly assigned to one of five regimens: oral placebo; oral alendronate, 1, 5, or 10 mg/d; or oral alendronate, 20 mg/d for 2 years followed by placebo during the third year (20/0 mg/d). Bone mineral density was measured by dual-energy x-ray absorptiometry. Bone turnover and bone quality were assessed with biochemical markers and bone histomorphometry. Alendronate at 5, 10, and 20/0 mg/d increased bone mineral density from baseline at the lumbar spine, femoral neck, and trochanter by 1% to 4% and in the total body by 0.3% to 1.0%; placebo led to losses of 2% to 4% at these sites. Alendronate, 1 mg/d, attenuated losses relative to those seen with placebo. Alendronate decreased markers of bone resorption to a new steady state by 3 months and decreased markers of bone formation by 6 to 12 months. Bone quality remained normal. At all dosages studied, alendronate had a safety and tolerability profile similar to that of placebo. In early postmenopausal women, alendronate given for 3 years at dosages of 5 mg/d or greater prevented the loss of bone mineral density at the spine and hip and in the total body. Alendronate seems to be a safe and effective nonhormonal option for prevention of postmenopausal bone loss.