The cognitive effects of estrogen were no different in women who started taking the hormone within 6 years of menopause, compared with those who began it 10 or more years after menopause, based on data from the double-blind randomized ELITE-Cog trial.

“Some hormone effects on cognition are postulated to vary by age or by timing in relation to the menopause,” wrote Victor W. Henderson, M.D., of Stanford (Calif.) University and his colleagues ( Neurology. 2016 Jul 20. doi: 10.1212/WNL.0000000000002980 ).

To test whether the timing of estrogen therapy affected the primary cognitive endpoint of verbal episodic memory, the researchers conducted the ELITE (Early vs. Late Intervention Trial With Estradiol) trial in which they randomized 567 healthy women within 6 years of menopause or 10 or more years post menopause to 1 mg/day of oral 17-beta-estradiol or a placebo. Women with a uterus also received either 45 mg progesterone as a 4% vaginal gel or a matched placebo gel.

The main ELITE trial tested the effect of the timing of estradiol, compared with placebo, on the progression of subclinical atherosclerosis, whereas the ELITE-Cog trial assessed the effects of the timing of estradiol on a composite test of verbal episodic memory.

Overall, composite scores of verbal memory were not significantly different in women randomized to estrogen vs. placebo based on a mean standardized difference of –0.06 (95% confidence interval, –0.22 to 0.09) after an average of 57 months of treatment. The mean standardized difference was similar in the early and late treatment groups. In addition, the mean standardized differences in measures of executive functions (–0.04; 95% CI, –0.21 to 0.14) and global cognition (–0.025; 95% CI, –0.18 to 0.13) were not significantly different between women who started estrogen within 6 years of menopause and those who started estrogen 10 years or more after menopause. Safety profiles were similar between the groups.

“Results of this randomized, double-blind placebo-controlled trial fail to confirm the timing hypothesis for cognitive outcomes in healthy postmenopausal women,” the researchers wrote.

The results don’t generalize to other subgroups including women of reproductive age, those in transition to menopause, or those with premature menopause caused by surgery or chemotherapy, and the study “was not designed to assess short-term cognitive effects of estradiol or effects on risks of mild cognitive impairment or Alzheimer disease,” the researchers noted. However, the findings should be reassuring to healthy, younger postmenopausal women considering estrogen therapy, they said.

The study was supported by a grant from the National Institutes of Health, and the study drugs and placebo were supplied by Teva, Watson, and Abbott Laboratories. Dr. Henderson disclosed research support from the NIH, as well as travel expenses from the NIH, American Academy of Neurology, and International Menopause Society.