Prevention of postmenopausal bone loss: six-year results from the Early Postmenopausal Intervention Cohort Study.

We report the effect of continuous treatment with alendronate for 6 yr vs. placebo in the Early Postmenopausal Intervention Cohort study. A total of 1609 healthy, early postmenopausal women were recruited; we describe results for the 585 women who received continuous placebo or alendronate (2.5 or 5 mg) daily for 6 yr. Bone mineral density (BMD) was evaluated at the lumbar spine, hip, forearm, and total body at baseline and annually thereafter. Bone turnover markers were measured every 6 months from baseline to yr 2 and annually thereafter. Adverse experiences, including upper gastrointestinal events and fractures, were recorded throughout the study. Women receiving placebo experienced progressive decreases in BMD at all skeletal sites. Patients receiving alendronate experienced significant gains in spine and hip BMD that were maintained through yr 6. Significantly greater, dose-related decreases in bone turnover markers in the alendronate groups vs. placebo occurred within the first year and were sustained through yr 6. Women receiving alendronate had adverse experience incidences similar to those receiving placebo. Fractures occurred in 11.5, 10.3, and 8.9% of women taking placebo, 2.5 mg alendronate, or 5 mg alendronate daily, respectively. Therapy with alendronate is an effective and promising strategy for the prevention of postmenopausal osteoporosis.