The life-time risk of a hip fracture depends on age and bone density. Treatment of osteopenia depends on age and the presence of other risk factors for fractures. For women between 50 and 70, the best prevention is estrogen with calcium and exercise. The long-term safety of alendronate is unknown, so it is not wise to use it for prevention unless there are other strong risk factors. There is no evidence that using a combination of these medications helps to prevent osteoporotic fractures - but it does add to the expense and potential toxicity.
Osteoporosis is a serious disease and prevention is important.
Young women with osteopenia should not be frightened, but should be concerned enough to discuss estrogen with their physician so that they do not develop osteoporosis in the future.