Background: In postmenopausal women, estrogen may have a beneficial effect on cognition or reduce the risk of decline in cognitive function. Whether raloxifene, a selective estrogen-receptor modulator, might have similar actions is not known.
Methods: As part of the Multiple Outcomes of Raloxifene Evaluation trial, we studied 7478 postmenopausal women with osteoporosis (mean age, 66 years), who were enrolled at 178 sites in 25 countries. The women were randomly assigned to receive raloxifene (60 mg or 120 mg) or placebo daily for three years. We compared the mean scores of the groups on six tests of cognitive function, which were administered at base line and at six months and one, two, and three years. Women were classified as having a decline in cognitive function if the change in their scores at three years was in the worst 10 percent.
Results: The mean cognitive scores in the three groups of women were similar at base line. The scores improved slightly in all three groups during the three-year study period, with no significant differences among the groups. The risk of decline in the cognitive function, as measured by four of the six tests, did not differ significantly between the two raloxifene groups combined and the placebo group, but there was a trend toward less decline in the combined raloxifene group on the two tests of verbal memory (relative risk, 0.77) and attention, (relative risk, 0.87). Newly reported or worsening hot flashes did not negatively influence test scores or the effect of treatment on test performance.
Conclusions: Raloxifene treatment for three years does not affect overall cognitive scores in postmenopausal women with osteoporosis.