This study was conducted among women who had previously received alendronate for 3 to 6 years during the Fracture Intervention Trial (FIT). Participants in the FLEX study were randomly assigned to receive alendronate (either 5 or 10 mg/day) or matching placebo during the next 5 years, in order to evaluate the effects of continuing or discontinuing alendronate treatment on bone mineral density and biochemical markers of bone turnover.