Either estrogen replacement or
Evista are good choices in prevention and progression of osteoporosis in postmenopausal women.
Evista may also protect against uterine and breast cancer. If you don't have true osteoporosis, and you are headed in that direction (osteopenia), then estrogen (or Evista) therapy is more appropriate for prevention, than the addition of Fosamax. At the point of osteopenia, Fosamax may be used at reduced doses for prevention of the progression to osteoporosis.