Differences in verbal memory performance in postmenopausal women receiving hormone therapy: 17ß-estradiol versus conjugated equine estrogens.

OBJECTIVE: Much controversy exists and many questions remain unanswered about the effects of hormone therapy (HT) on cognition in postmenopausal women. There is growing evidence suggesting that HT compounds containing conjugated equine estrogen (CEE) have negative effects on cognition whereas 17ß-estradiol (17ß-E) either has positive or neutral effects. The present study sought to further examine this issue in a sample of postmenopausal women with risk factors for Alzheimer's disease (AD). DESIGN: Cross-sectional neuropsychological evaluation. SETTING: Academic research clinic. PARTICIPANTS: 68 healthy postmenopausal women (aged 49-68) receiving either 17ß-E or CEE for at least one year with increased risk for AD. MEASUREMENTS: Neuropsychological test battery of the cognitive domains of attention/working memory/processing speed, verbal memory, visual memory, and executive functioning. RESULTS: Multivariate analyses of variance (MANOVA) showed significantly better verbal memory performance in women receiving 17ß-E compared to women receiving CEE regardless of age, IQ, years of education, risk factors for AD (including APOE-ε4 carriership), duration of endogenous and exogenous estrogen exposure, concurrent progesterone use, or natural versus surgical menopause status. CONCLUSIONS: Verbal memory performance was better in postmenopausal women receiving 17ß-E compared to CEE in a sample population of women with risk factors for AD. Genetic risk for AD as well as other confounds did not affect this finding. The results suggest a differential effect of HT type on verbal memory, with 17ß-E being a preferential compound. Further evaluation of HT types, regimens and duration of use on cognitive performance in postmenopausal women in a controlled longitudinal design is warranted.

Insulin resistance and hippocampal volume in women at risk for Alzheimer's disease.

Insulin resistance (IR) is the main pathological condition underlying vascular disorders, such as diabetes and cardiovascular disease, which are well established risk factors for cognitive decline and Alzheimer disease (AD). Hippocampal atrophy has been associated with cognitive decline, but little is known about the influence of IR on hippocampus integrity in non-diabetic, cognitively intact individuals. Herein, 50 women ages 50-65, current users of hormone therapy, underwent magnetic resonance imaging, cognitive testing, and homeostatic assessment of insulin resistance (HOMA-IR), as part of a longitudinal study examining brain structure and function in postmenopausal women at risk for AD. Results demonstrated a significant negative relationship between HOMA-IR and right and total hippocampal volume, overall cognitive performance, and selective tests of verbal and non-verbal memory. The main effect of HOMA-IR on brain structure and cognition was not altered by the presence of APOE-ε4 allele or by reproductive history, such as duration of endogenous and exogenous estrogen exposure. These results suggest that IR in middle-aged individuals at risk for AD may be biomarker for dementia risk.