The influence of hormone replacement therapy on the aging-related change in cognitive performance. Analysis based on a Danish cohort study

Postmenopausal hormone therapy and cognition in twins

OBJECTIVE

Mild cognitive impairment may be caused by pathophysiological changes occurring decades prior to symptom development. It has been hypothesised that oestrogen can prevent such changes. We aimed to investigate the association between postmenopausal hormone therapy and cognition in Danish female twins and to examine differences in this association before and after publication of the findings from the Women's Health Initiative study in 2002.

STUDY DESIGN

This study includes cognitive assessment of 4510 twins aged 50+ years. Information on hormone therapy was obtained through Danish health registries. The association between current hormone therapy use and cognition was analysed in twins aged 50+ using both cross-sectional, intrapair and longitudinal analysis, adjusting for age, education, social class, and unobserved familial confounding.

RESULTS

Cross-sectionally, systemic HT users aged 70+ had a significantly lower cognitive function than non-users, whereas systemic HT users aged 50-69 did not differ from non-users before 2002. Longitudinal data in younger twins aged 50-69 showed a significantly lower cognitive function in systemic HT users after 2002 compared to non-users. Systemic HT users aged 70+ showed that the lower cognitive function was most explicit before 2002, whereas after 2002 the cognitive function was closer to non-users. Twins aged 50-69 who changed from systemic HT to local HT after 2002, or dropped it altogether, performed cognitively better.

CONCLUSIONS

Our findings cautiously indicate a change in the association between cognition and hormone therapy use after 2002, which suggests an alteration in the hormone therapy user profile in the wake of the 2002 WHI publication.

Postmenopausal hormone treatment alters neural pathways but does not improve verbal cognitive function

OBJECTIVE

Cognitive outcomes in trials of postmenopausal hormone treatment have been inconsistent. Differing outcomes may be attributed to hormone formulation, treatment duration and timing, and differential cognitive domain effects. We previously demonstrated treatment benefits on visual cognitive function. In the present study, we describe the effects of hormone treatment on verbal outcomes in the same women, seeking to understand the effects of prior versus current hormone treatment on verbal function.

METHODS

This is a cross-sectional evaluation of 57 women (38 hormone users [25 prior long-term users and 13 current users] and 19 never-users). Hormone users took identical formulations of estrogen or estrogen + progestin (0.625 mg/d conjugated equine estrogens with or without medroxyprogesterone acetate) for at least 10 years, beginning within 2 years of menopause. Women were evaluated with tests of verbal function and functional magnetic resonance imaging (fMRI) of a verbal discrimination task.

RESULTS

All women scored similarly on assessments of verbal function (Hopkins Verbal Learning Test and a verbal discrimination task performed during the fMRI scanning session); however, women ever treated with hormones had more left inferior frontal (T = 3.72; P < 0.001) and right prefrontal cortex (T = 3.53; P < 0.001) activation during the verbal task. Hormone-treated women performed slightly worse on the verbal discrimination task (mean accuracy 81.72 ± 11.57 ever-treated, 85.30 ± 5.87 never-treated, P = 0.14), took longer to respond (mean reaction time 1.10 ± 0.17 s ever-treated, 1.02 ± 0.11 never-treated, P = 0.03), and remembered fewer previously viewed words (mean accuracy 62.21 ± 8.73 ever-treated, 65.45 ± 7.49 never-treated, P = 0.18). Increased posterior cingulate activity was associated with longer response times (R = 0.323, P = 0.015) and worse delayed verbal recall (R = -0.328, P = 0.048), suggesting that increased activation was associated with less efficient cognitive processing. We did not detect between group differences in activation in the left prefrontal cortex, superior frontal cortex, thalamus, or occipital/parietal junction.

CONCLUSIONS

Although current and past hormone treatment was associated with differences in neural pathways used during verbal discrimination, verbal function was not higher than never-users.

Postmenopausal hormone therapy and cognition: effects of timing and treatment type

SETTING

Hormone therapy used for the management of postmenopausal symptoms in older women appears to result in variable effects on cognitive function, depending on study design, subjects, tests used, and types of therapy.

OBJECTIVE

To determine the effects of estrogen-only and estrogen plus progestogen preparations on cognitive performance (cognitive status, general and working memory) when taken 'early' and 'late' from the onset of menopause.

METHOD

The study consisted of 410 women who were participants in a longitudinal study, first recruited at age 40-80 years. They were tested for change over 5 years as an observational cohort by the Mini-Mental State Examination, National Adult Reading Test and the Wechsler Memory Scale Version 3. Cognitive decline, measured by age-adjusted scores, was defined as >or=10% negative change in each individual woman.

RESULTS

Controlling for age and lifestyle factors, and using the criterion of decrease in score >or=10% over 5 years for 'cognitive decline', 'early start' of hormone therapy (<3 years from menopause) was strongly associated with reduction in risk by the Mini-Mental State Examination (estrogen-only preparation, p = 0.005) but with increase in risk for general memory (with estrogen plus progestogen preparation, p = 0.02). Overall, there were no major effects on subgroups with type/timing of hormone therapy in relation to testing for a negative change in cognitive function.

CONCLUSION

'Early start' of estrogen-only hormone therapy was associated with reduced risk of global cognitive decline, and 'early start' estrogen-only and estrogen/progestogen hormone therapies showed increased risks of general memory decline. Even though this study did not have the power to discriminate between minor and mixed effects, it suggests that cognitive effects of hormone therapies may be mixed, depending on cognitive domain and timing of use/type of preparation.

Dehydroepiandrosterone and age-related cognitive decline

In humans the circulating concentrations of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) decrease markedly during aging, and have been implicated in age-associated cognitive decline. This has led to the hypothesis that DHEA supplementation during aging may improve memory. In rodents, a cognitive anti-aging effect of DHEA and DHEAS has been observed but it is unclear whether this effect is mediated indirectly through conversion of these steroids to estradiol. Moreover, despite the demonstration of correlations between endogenous DHEA concentrations and cognitive ability in certain human patient populations, such correlations have yet to be convincingly demonstrated during normal human aging. This review highlights important differences between rodents and primates in terms of their circulating DHEA and DHEAS concentrations, and suggests that age-related changes within the human DHEA metabolic pathway may contribute to the relative inefficacy of DHEA replacement therapies in humans. The review also highlights the value of using nonhuman primates as a pragmatic animal model for testing the therapeutic potential of DHEA for age-associate cognitive decline in humans.

Cognitive benefits of hormone therapy: cardiovascular factors and healthy-user bias

OBJECTIVE

The Women's Health Initiative (WHI) study and its ancillary Memory Study (WHIMS) revealed increased rates of cardiovascular risk, cognitive decline and dementia with opposed conjugated equine estrogens (CEE). As a result, previously accepted observational data suggesting cardiovascular and cognitive benefits and reduced risk for dementia with hormone therapy (HT) were largely attributed to 'healthy-user' bias. The present observational, community-based, case-controlled study examined the 'healthy-user' bias theory by comparing cognitive task performance in two groups of postmenopausal women, who were either HT users or non-users.

DESIGN

Participants were 213 non-demented, postmenopausal women residing in the community and in assisted-living facilities who completed a self-report health questionnaire and underwent a 1-h cognitive test battery. To study the independent contribution of variables in the prediction of cognitive performance, we employed a series of hierarchical regression models adding terms in three stages. The first stage included only HT, the second stage added demographics, and the last stage added alcohol, depression and a cardiovascular risk factor (CVRF) composite derived from a confirmatory factor analysis. The CVRF composite consisted of: stroke, diabetes, hypertension, and hypercholesterolemia.

RESULTS

Although independent samples t-tests revealed no statistically significant differences in the CVRF composite and its individual components between the two groups, HT users tended to possess fewer CVRF than non-users. Conversely, HT users were younger and more educated than non-users. HT users outperformed non-users on 7/9 cognitive variables. The full regression model controlling for CVRF, demographic variables, and mood showed HT users outperformed non-users on measures of verbal memory and abstract reasoning.

CONCLUSIONS

While there is some evidence HT users possess fewer preexisting CVRF than non-users, the observed positive association between HT and cognition is not completely explained by this trend.

Role of androgens, progestins and tibolone in the treatment of menopausal symptoms: a review of the clinical evidence

Estrogen-containing hormone therapy (HT) is the most widely prescribed and well-established treatment for menopausal symptoms. High quality evidence confirms that estrogen effectively treats hot flushes, night sweats and vaginal dryness. Progestins are combined with estrogen to prevent endometrial hyperplasia and are sometimes used alone for hot flushes, but are less effective than estrogen for this purpose. Data are conflicting regarding the role of androgens for improving libido and well-being. The synthetic steroid tibolone is widely used in Europe and Australasia and effectively treats hot flushes and vaginal dryness. Tibolone may improve libido more effectively than estrogen containing HT in some women. We summarize the data from studies addressing the efficacy, benefits, and risks of androgens, progestins and tibolone in the treatment of menopausal symptoms.

Estrogen abolishes latent inhibition in ovariectomized female rats

Estrogen is frequently prescribed as a method of birth control and as hormone replacement therapy for post-menopausal women with varied effects on cognition. Here the effects of estrogen on attention were examined using the latent inhibition (LI) behavioral paradigm. Ovariectomized (OVX) female rats were given either estrogen benzoate (EB, 10 or 100 microg/ml/kg; SC) or sesame oil vehicle. Males and OVX females receiving vehicle displayed normal LI. In contrast, LI was abolished in OVX females receiving EB. The lack of LI in OVX females receiving EB was a result of low suppression ratios, reflecting strong conditioning between the tone and the shock in these subjects even if they were pre-exposed to the tone. Thus, estrogen impaired the ability of OVX females to ignore irrelevant stimuli. Since different cognitive tasks vary in their required ability to ignore irrelevant stimuli, these results may account for some of the variations in the current literature on estrogen and cognition.

[The benefits and risks of hormonal replacement therapy--an update]

Hormonal replacement therapy (HRT) with estrogens and gestagens has been used for more than 40 years in the treatment of menopausal complaints and can be considered an effective treatment for vaso-vegetative symptoms and urogenital atrophy. During the past few years many women and doctors have revised their opinions of HRT. The reasons for this change of view are mainly three large international studies: the Heart and Estrogen/Progestin Study, the Women's Health Initiative Study and the One Million Women Study. In this review we summarize the data from the most important studies and point out the actual status of the controversial discussion on the benefits and risks of HRT.

Hormone replacement therapy and cognitive performance in postmenopausal women—a review by cognitive domain

Laboratory, animal and neuroimaging evidences suggest that hormone replacement therapy (HRT) may be beneficial to human cognition. This systematic review includes 26 studies on the association between HRT and cognition and 17 studies on HRT and risk of dementia. It was hypothesised that HRT would have a positive association with cognitive speed and verbal memory and possibly visual memory but not with executive functioning, and would be associated with a decreased risk of dementia. Evidence for HRT's neuroenhancing and neuroprotective properties was also evaluated. There was significant statistical and clinical heterogeneity among studies precluding meta-analysis. Results showed no consistent relationship between HRT and performance in any cognitive domain. Cross-sectional studies tended to report more positive results than longitudinal studies and randomised-controlled trials, particularly in the areas of verbal memory and executive functioning. HRT was associated with decreased risk of dementia in observational studies, but with increased risk in one randomised-controlled trial. Cognitive improvement or maintenance are not secondary benefits of HRT.

Treatment of menopausal symptoms: what shall we do now?

During the past few years, many women and doctors have revised their opinions of hormone replacement therapy (HRT) for menopausal symptoms, and a substantial number of individuals have discontinued its use because of concerns about side-effects. Numerous alternatives to HRT are promoted, and assessment of the quality of evidence about the safety and effectiveness of these compounds can be difficult. In this Review, we summarise the data from studies addressing the efficacy, risks, and benefits of frequently prescribed treatments, and offer evidence-based clinical guidelines for the management of menopausal symptoms. Although few comparative studies exist, oestrogen alone or combinations of oestrogen and progestagen are likely to be the most effective treatments for menopausal hot flushes and vaginal dryness. Tibolone is as effective as HRT, however, and might also improve libido. For those who wish to avoid hormonal treatments, there are few effective options. Selective serotonin reuptake inhibitors might be effective in the very short term (less than 12 weeks) and are well tolerated. There is not enough evidence that any of the complementary therapies available are any better than placebo for menopausal vasomotor symptoms, and few safety data exist.

Age-related cognitive decline in the menopause: effects of hormone replacement therapy on cognitive event-related potentials

OBJECTIVE

Although epidemiological and clinical studies suggest that hormone replacement therapy (HRT) may protect against cognitive disorders and neurodegenerative diseases, the relation between estrogen and cognition in postmenopausal women remains controversial.

METHODS

In a double-blind placebo-controlled, parallel group design study the effects of HRT with the estrogen-progestogen combination Presomen 1.25 compositum((R)) (1.25mg equine conjugated estrogens administered for 21 days plus the progestogen 5mg medrogeston given for 11 days) on event-related potentials (ERPs) in postmenopausal patients with age-related cognitive decline (DSM-IV code 780.9, ICD-10 code R 41.8) were investigated. After a pre-drug comparison with age-matched normal postmenopausal controls, 48 psychotropic drug-free patients aged 60 +/- 6 years were randomized to receive either placebo or verum for 4 months. ERPs were recorded before as well as on the 91-92 days of the study, which thus fell into the estrogen phase of the treatment during the fourth cycle.

RESULTS

At baseline, patients showed a lengthening of P300 latency and an attenuation of P300 amplitudes as compared with normal controls. After HRT with Presomen, a significant shortening of P300 latency as compared with placebo was observed.

CONCLUSIONS

The baseline P300 differences suggest that in the patient group the aging process was advanced, while after HRT with Presomen a significant improvement and normalization of information processing as indexed by P300 was observed.