Relationship between Use of Cholesterol-Lowering Drugs (Statins) and Osteoporosis in Women after Menopause

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The summary below is from the full report titled "Statin Use, Clinical Fracture, and Bone Density in Postmenopausal Women: Results from the Women's Health Initiative Observational Study." It is in the 15 July 2003 issue of Annals of Internal Medicine (volume 139, pages 97-104). The authors are A.Z. LaCroix, J.A. Cauley, M. Pettinger, J. Hsia, D.C. Bauer, J. McGowan, Z. Chen, C.E. Lewis, S.G. McNeeley, M.D. Passaro, and R.D. Jackson.

What is the problem and what is known about it so far?

In osteoporosis, bones become less dense and more fragile and bone fractures occur more easily. Since the hormone estrogen keeps bone dense, osteoporosis is especially common in women after menopause as estrogen levels drop. Estimates suggest that half of all women will have an osteoporosis-related fracture after menopause. Health habits that prevent osteoporosis include adequate calcium and vitamin D intake, exercise, and avoiding tobacco and alcohol. Because broken bones (fractures) can be painful, costly, and disabling, it is important to prevent osteoporosis or to treat it at early stages before fractures occur. Statins (also called 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are drugs that doctors usually prescribe to treat high cholesterol. Laboratory studies show that statins have a favorable effect on bones. However, studies that have looked at whether people who take statins have fewer bone fractures than people who do not take statins have had mixed results, so it remains uncertain whether statins prevent osteoporosis.

Why did the researchers do this particular study?

To see whether women who take statins are less likely to develop osteoporosis and bone fractures than women who do not take statins.

Who was studied?

93,716 women 50 to 79 years of age who were participating in a large study of women after menopause. The women were from 40 health care centers in the United States.

How was the study done?

The researchers examined each woman when she enrolled in the study and collected information about her health, including statin use and osteoporosis. They then sent each woman a yearly questionnaire until the end of the study. Because women were enrolled at different times, the researchers followed women for at least 2 years and a maximum of 6 years. The researchers then compared the frequency of bone fractures in women who did and women who did not use statins. Women from 3 health centers also had a test (dual-energy x-ray absorptiometry) to measure bone density at the start of the study.

What did the researchers find?

Of the 93,716 women in the study, 7846 were taking statins when they entered the study. Women who took statins tended to be older, to be heavier, and to have a history of heart disease than women who did not use statins. Women who took statins were just as likely to have a fracture as women who did not take statins, even after accounting for these differences.

What were the limitations of the study?

While this study is better than previous ones, few women in the study had taken statin medications for more than 3 years, so it was difficult to detect a small benefit of long-term statin use with respect to fractures. Also, the women who took statins may be different from the women who did not in ways that the researchers could not account for.

What are the implications of the study?

This study suggests that doctors and patients should not use statins to prevent osteoporosis and related fractures.