About 15% of postmenopausal women will eventually break their hip, and about 20% will develop fractures of the spine. These fractures usually start to occur about age 70. Ideally, we would like to prevent all these osteoporotic fractures. However, there are problems with all of the medications that are currently available, so prescription medications should be reserved for those women with the highest risk. All women should follow basic prevention recommendations: stop smoking, exercise, eat 1200 to 1500 mg of calcium a day, take vitamin D, and don't diet too much.
How can you tell if you are a woman at high risk? Bone density is one important risk factor. Because bone density naturally decreases with aging, 45% of white women aged 55 have "osteopenia" - but this does not mean they all need drug therapy. Physicians have not reached consensus about when to medicate women, but I think it is reasonable to treat those in the lowest 20% (at age 50, this is a hip T-score of -1.6). At that point, the risk of a future hip fracture is about twice that of a woman with average bone density.
Other risk factors include hip fractures in a close relative, low weight, and smoking. Women who have other medical problems or who take certain medicines may also be at higher risk. If you have had a fragility fracture since age 50 (not caused by a severe accident), you are in a different category and need treatment, not prevention, so the following comments do not apply.
For women who have not had a fracture but who are at high risk, the best choice of medication is not really clear! Recent studies have found problems with hormone replacement, and the other osteoporosis medications are too new to know effects after 20 years. Therefore, the choice must be made on an individual basis. This list gives the current pro's and con's of available treatments, roughly in the order I personally favor. Sometimes the choice will be no prescription medications, just basic prevention and wait until age 65 or later to start medications.
Currently many physicians do not recommend estrogen for anything except menopausal symptoms. I no longer start estrogens in women older than 60, but in younger women I think they are a good choice to prevent osteoporosis. Lower doses have fewer side effects and still partly protect the skeleton.
Susan Ott, M.D.