Postmenopausal women taking the drug Evista to prevent and treat the bone-thinning disease Osteoporosis may also reduce their risk of mild cognitive impairment and dementia, the results of a new study suggest.

Evista is known generically as raloxifene. Dr. Kristine Yaffe, at the University of California, San Francisco, and associates followed 5386 women enrolled in the Multiple Outcomes of Raloxifene Evaluation (MORE) study. The participants were randomly assigned to low-dose or high-dose raloxifene or an inactive placebo.

After nearly four years, on average, the women were screened for dementia and cognitive impairment. Mild cognitive impairment was diagnosed in 181 and dementia in 52, the investigators report in the American Journal of Psychiatry.

Compared with those on placebo, women taking higher-dose raloxifene had a 33 percent lower risk of developing mild cognitive impairment.

“One case of mild cognitive impairment was prevented for every 91 women treated,” the authors point out.

However, the lower dose of raloxifene had no significant effect on cognitive impairment compared with placebo.

While both doses are effective in treating osteoporosis, “it is possible that higher doses of raloxifene are needed to cross the blood-brain barrier,” Yaffe’s team suggests.

Longer trials or studies enrolling women at high risk will be needed to establish the effect of raloxifene more firmly in preventing cognitive impairment, they add.

SOURCE: American Journal of Psychiatry, April 2005.