Claims that cholesterol-lowering drugs also prevent fractures and bone loss in postmenopausal women don't hold up against new data, according to research led by investigators in the Public Health Sciences Division.
In a study involving more than 90,000 women, Dr. Andrea LaCroix and colleagues in the Women's Health Initiative found that women between the ages of 50 and 79 who took statins-drugs that include Zocor, Pravachol and Lipitor-were no less likely to develop fractures than women who did not take the medications. Bone density between statin users and nonusers also did not differ significantly.
The conclusions do not support the promise of earlier studies that found statins could stimulate bone formation in cultured cells and increase bone volume in rats.
LaCroix, co-principal investigator of the WHI clinical coordinating center in PHS, said that the large-scale study showed no support that the statins in current use today mitigate bone loss in an actual population of menopausal women.
"Based on our findings, statins should not be used for the prevention or treatment of osteoporosis," she said.
The findings are published in the July 15 of the Annals of Internal Medicine.
The WHI, which is funded by the National Heart Lung and Blood Institute and private donations, is a 15-year, nationwide randomized trial and observational study designed to find ways to prevent cardiovascular disease, osteoporosis and cancer.
The 93,716 participants in the observational arm of the WHI reported all medication use at the time of their enrollment and in follow-up visits in subsequent years. Of postmenopausal women, 7,846 were statin users.
Researchers compared rates of hip, lower arm or wrist and other fractures between the statin users and nonusers. In addition, for 6,442 women enrolled at three WHI clinical centers, bone-density measurements were taken of the hip, spine and total body and compared among women who took statins and those who did not.
After a follow-up period ranging from two to six years, scientists found no statistically significant differences between the two groups for either analysis.
Importance of clinical trials
LaCroix said that the results, while disappointing, emphasize the valuable role large population studies play in evaluating interesting new hypotheses.
"Recently, wide-ranging benefits have been attributed to statins," LaCroix said. "They are purported to prevent fractures, breast cancer, Alzheimer's disease and multiple sclerosis. But the studies that generated these hypotheses are mostly small, clinical studies or epidemiologic studies based on administrative databases with very limited data on potential confounding factors. It will likely be necessary to conduct a large, randomized trial of statin use focusing on noncardiovascular outcomes to provide definitive evidence on the benefits and risks of statin use.
"Our experience with combined-hormone therapy provides a clear example of how necessary such trials are before medicines are widely used for indications that have not been proven using experimental designs."