Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the clinic subcohort of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial and meta-analysis of 3 cognitive studies within COSMOS.

BACKGROUND: Longer effects of multivitamin-mineral (MVM) supplementation on late-life cognitive function remain untested using in-person, detailed neuropsychological assessments. Furthermore, insufficient evidence exists for healthcare providers to recommend daily MVM supplements to prevent cognitive decline. OBJECTIVES: This study aimed to test MVM effects on cognitive change using in-person, detailed neuropsychological assessments and conduct a meta-analysis within COSMOS (COcoa Supplement and Multivitamin Outcomes Study) cognitive substudies for a robust evaluation of MVM effects on cognition. METHODS: COSMOS is a 2 × 2 factorial trial of cocoa extract (500 mg flavanols/d) and/or a daily MVM supplement for cardiovascular disease and cancer prevention among 21,442 United States adults aged ≥60 y. There were 573 participants in the clinic subcohort of COSMOS (that is, COSMOS-Clinic) who completed all cognitive tests administered at baseline. For the meta-analysis, we included nonoverlapping participants across 3 COSMOS cognitive substudies: COSMOS-Clinic (n = 573); COSMOS-Mind (n = 2158); COSMOS-Web (n = 2472). RESULTS: In COSMOS-Clinic, we observed a modest benefit of MVM compared with placebo on global cognition over 2 y {mean difference [95% confidence interval (CI)] = 0.06 SD units (SU) (-0.003, 0.13)}, with a significantly more favorable change in episodic memory [mean difference (95% CI) = 0.12 SU (0.002, 0.23)] but not in executive function or attention [mean difference (95% CI) = 0.04 SU (-0.04, 0.11)]. The meta-analysis of COSMOS substudies showed clear evidence of MVM benefits on global cognition [mean difference (95% CI) = 0.07 SU (0.03, 0.11); P = 0.0009] and episodic memory [mean difference (95% CI) = 0.06 SU (0.03, 0.10); P = 0.0007]; the magnitude of effect on global cognition was equivalent to reducing cognitive aging by 2 y. CONCLUSIONS: In COSMOS-Clinic, daily MVM supplementation leads to a significantly more favorable 2-y change in episodic memory. The meta-analysis within COSMOS cognitive substudies indicates that daily MVM significantly benefits both global cognition and episodic memory. These findings within the COSMOS trial support the benefits of a daily MVM in preventing cognitive decline among older adults. This trial was registered at COSMOS-clinicaltrials.gov as NCT02422745, at COSMOS-Mind-clinicaltrials.gov as NCT03035201, and at COSMOS-Web-clinicaltrials.gov as NCT04582617.

Diet Effects on Cerebrospinal Fluid Amino Acids Levels in Adults with Normal Cognition and Mild Cognitive Impairment.

BACKGROUND: Exploration of cerebrospinal fluid (CSF) amino acids and the impact of dietary intake on central levels may provide a comprehensive understanding of the metabolic component of Alzheimer's disease. OBJECTIVE: The objective of this exploratory study was to investigate the effects of two diets with varied nutrient compositions on change in CSF amino acids levels in adults with mild cognitive impairment (MCI) and normal cognition (NC). Secondary objectives were to assess the correlations between the change in CSF amino acids and change in Alzheimer's disease biomarkers. METHODS: In a randomized, parallel, controlled feeding trial, adults (NC, n = 20; MCI, n = 29) consumed a high saturated fat (SFA)/glycemic index (GI) diet [HIGH] or a low SFA/GI diet [LOW] for 4 weeks. Lumbar punctures were performed at baseline and 4 weeks. RESULTS: CSF valine increased and arginine decreased after the HIGH compared to the LOW diet in MCI (ps = 0.03 and 0.04). This pattern was more prominent in MCI versus NC (diet by diagnosis interaction ps = 0.05 and 0.09), as was an increase in isoleucine after the HIGH diet (p = 0.05). Changes in CSF amino acids were correlated with changes in Alzheimer's disease CSF biomarkers Aß42, total tau, and p-Tau 181, with distinct patterns in the relationships by diet intervention and cognitive status. CONCLUSION: Dietary intake affects CSF amino acid levels and the response to diet is differentially affected by cognitive status.

Recruitment of a multi-site randomized controlled trial of aerobic exercise for older adults with amnestic mild cognitive impairment: The EXERT trial.

INTRODUCTION: Effective strategies to recruit older adults with mild cognitive impairment (MCI) into nonpharmacological intervention trials are lacking. METHODS: Recruitment for EXERT, a multisite randomized controlled 18-month trial examining the effects of aerobic exercise on cognitive trajectory in adults with amnestic MCI, involved a diverse portfolio of strategies to enroll 296 participants. RESULTS: Recruitment occurred September 2016 through March 2020 and was initially slow. After mass mailings of 490,323 age- and geo-targeted infographic postcards and brochures, recruitment rates increased substantially, peaking at 16 randomizations/month in early 2020. Mass mailings accounted for 52% of randomized participants, whereas 25% were recruited from memory clinic rosters, electronic health records, and national and local registries. Other sources included news broadcasts, public service announcements (PSA), local advertising, and community presentations. DISCUSSION: Age- and geo-targeted mass mailing of infographic materials was the most effective approach in recruiting older adults with amnestic MCI into an 18-month exercise trial.

Design and baseline characteristics of the cocoa supplement and multivitamin outcomes study for the Mind: COSMOS-Mind.

BACKGROUND: Large simple trials are potentially efficient and cost-effective approaches to assess interventions to preserve cognitive function in older adults. High-dose cocoa flavanols supplementation is a promising intervention that warrants additional testing. We describe the design, recruitment success, and baseline characteristics of the Cocoa Supplement and Multivitamin Outcomes Study for the Mind (COSMOS-Mind) trial. METHODS: COSMOS-Mind is an ancillary study to the large-scale and predominantly mail-based COSMOS randomized controlled clinical trial. COSMOS is assessing whether cocoa extract (including 600 mg/d cocoa flavanols) and a multivitamin reduce risks for major cardiovascular events and total invasive cancer. COSMOS-Mind uses telephone-based interviews to assess cognitive function and impairment to determine whether cocoa flavanols benefit cognitive function in adults aged 65 years or older, targeting the enrollment of 2000 participants to provide >90% statistical power across 3 years of annual follow-up. RESULTS: Of the 3224 COSMOS screenees who expressed interest in COSMOS-Mind, 2350 (76%) successfully completed baseline cognitive assessments and 2262 (96%) geographically diverse, eligible individuals were ultimately enrolled over one year. At baseline, the primary outcome, a composite of cognitive test scores, was inversely associated with age in a manner consistent with assumptions used in projections of statistical power. CONCLUSIONS: Older adults are willing to enroll in large simple trials that include telephone-based cognitive assessments. Embedding these trials in large studies of other health outcomes is efficient and expands the scientific knowledge gained from the research. ClinicalTrials.gov Identifiers: NCT03035201 (COSMOS-Mind); NCT102422745 (parent COSMOS).

Higher amounts of sedentary time are associated with short sleep duration and poor sleep quality in postmenopausal women.

STUDY OBJECTIVES: To evaluate the associations between sedentary time, total (total-PA), light (light-PA), moderate (MOD-PA), and vigorous (VIG-PA) physical activity with indices of sleep in postmenopausal women. METHODS: Baseline self-reported data from the Women's Health Initiative Observational Study (n = 75 074) were used in this cross-sectional analysis. Total-PA, light-PA, MOD-PA, and VIG-PA were categorized by metabolic equivalents of the activity (MET-hour [hr]/week [wk]) and were estimated using validated questionnaires. Sedentary time was categorized by hr/day and was estimated via questionnaire. Logistic regression was used to examine the associations between these variables and short sleep (≤6 hr/night), long sleep (≥10 hr/night), poor sleep quality, and insomnia symptoms after adjustment for age, race, socioeconomic status, body mass index, health status, depressive symptoms, smoking status, alcohol use, hormone therapy, and comorbidities. RESULTS: Higher sedentary time (>11 hr/day) was associated with higher odds of short sleep (odds ratio [OR] = 1.80, 95% confidence interval [CI]: 1.72-1.88), poor sleep quality (OR = 1.85, 95% CI: 1.74-1.97), and insomnia symptoms (OR = 1.56, 95% CI: 1.49-1.64). Light-PA (>0 MET-hr/wk) was associated with lower odds of short sleep (OR = 0.96, 95% CI: 0.92-1.00), and higher amounts of total-PA (OR = 0.90, 95% CI: 0.84-0.97), light-PA (OR = 0.94, 95% CI: 0.89-1.00), and MOD-PA (OR = 0.91, 95% CI: 0.86-0.97) were associated with lower odds of poor sleep quality. CONCLUSIONS: Our findings suggest that higher levels of light and moderate intensity physical activity are associated with better sleep quality, whereas higher amounts of sedentary time are associated with short sleep and lower quality sleep. Future studies should investigate the directionality of these associations and potential causal pathways.

Impact of a Multidomain Intensive Lifestyle Intervention on Complaints About Memory, Problem-Solving, and Decision-Making Abilities: The Action for Health in Diabetes Randomized Controlled Clinical Trial.

Background: Lifestyle interventions to reduce weight and increase activity may preserve higher-order cognitive abilities in overweight/obese adults with type 2 diabetes (T2D). Methods: Adults (N = 5,084) with T2D who enrolled in a randomized clinical trial of a 10-year intensive lifestyle intervention (ILI) compared with diabetes support and education were queried at baseline and repeatedly during follow-up for complaints about difficulties in memory, problem-solving, and decision-making abilities. Results: For those without baseline complaints, assignment to ILI was associated with lower odds that complaints would emerge during follow-up for decision-making ability (odds ratio [OR]=0.851, [95% CI, 0.748,0.967], p=0.014), and, among individuals who were not obese, lower odds that complaints would emerge about problem-solving ability (OR=0.694 [0.510,0.946]). No cognitive benefits from ILI were seen for individuals with baseline complaints about cognitive abilities. ILI may have exacerbated the severity of complaints about problem-solving ability during follow-up among individuals with baseline complaints and cardiovascular disease (OR=2.949 [1.378,6.311]). Conclusions: A long-term multidomain ILI may reduce the likelihood that complaints about difficulties in higher-order cognitive abilities will emerge in T2D adults without pre-existing complaints. Among those with pre-existing complaints, the ILI did not prevent increases in complaint severity.

Effects of Longitudinal Glucose Exposure on Cognitive and Physical Function: Results from the Action for Health in Diabetes Movement and Memory Study.

OBJECTIVES: To test whether average long-term glucose exposure is associated with cognitive and physical function in middle-aged and younger-old adults with type 2 diabetes mellitus. DESIGN: Prospective cohort study. SETTING: Data obtained as part of the Action for Health in Diabetes (Look AHEAD) trial (NCT00017953) and Look AHEAD Movement and Memory ancillary study (NCT01410097). PARTICIPANTS: Overweight and obese individuals with type 2 diabetes mellitus aged 45 to 76 at baseline (N = 879). MEASUREMENTS: Glycosylated hemoglobin (HbA1c) was measured at regular intervals over 7 years, and objective measures of cognitive function (Trail-Making Test, Modified Stroop Color-Word Test, Digit Symbol-Coding, Rey Auditory Verbal Learning Test, Modified Mini-Mental State Examination) and physical function (Short Physical Performance Battery, expanded Physical Performance Battery, 400-m and 20-m gait speed) and strength (grip and knee extensor strength) were assessed at the Year 8 or 9 follow-up examination. RESULTS: Average HbA1c exposure was 7.0 ± 1.1% (53 ± 11.6 mmol/mol), with 57% of participants classified as having HbA1c levels of less than 7% (<53 mmol/mol), 27% having levels of 7% to 8% (53-64 mmol/mol), and 16% having levels of greater than 8% (>64 mmol/mol). After adjustment for age, sex, race, education, smoking status, alcohol intake, knee pain, physical fitness, body mass index, diabetes mellitus medication and statin use, ancillary year visit, and study arm and site, higher HbA1c was associated with worse physical but not cognitive function. Further adjustment for prevalent diabetes mellitus-related comorbidities made all associations nonsignificant. Results did not differ when stratified according to participant baseline age (<60 vs ≥ 60). CONCLUSION: Results presented here suggest that, in the absence of diabetes mellitus-related complications, longitudinal glucose exposure is not associated with future cognitive and physical function. Optimal management of diabetes mellitus-related comorbidities may prevent or reduce the burden of disability associated with type 2 diabetes mellitus.

National Institute on Aging /Alzheimer's Association criteria for Mild Cognitive Impairment applied to chemotherapy treated breast cancer survivors.

BACKGROUND: In this analysis we use the National Institute on Aging/Alzheimer's Association (NIA/AA) criteria to identify Mild Cognitive Impairment (MCI) in a sample of breast cancer survivors treated with chemotherapy. METHODS: Sixty women ages 39-79 on a prospective clinical trial of donepezil were assessed at baseline using a battery of standardized/validated neurocognitive measures. Cognitive status was adjudicated to identify MCI by a panel of dementia experts. RESULTS: Fifty percent were not cognitively impaired, 43% met the NIA/AA criteria for MCI, 2% had dementia, and 5% could not be classified. DISCUSSION: In this sample, nearly half of breast cancer survivors met the NIA/AA criteria for MCI. We propose these criteria be used to define cancer-related Mild Cognitive Impairment (cMCI), providing a framework for conducting additional studies to further characterize cMCI and identify clinical, imaging, and genetic factors associated with the progression of cMCI to more advanced stages of cognitive impairment.

Comparing biological markers of Alzheimer's disease across blood fraction and platforms: Comparing apples to oranges.

INTRODUCTION: This study investigated the comparability of potential Alzheimer's disease (AD) biomarkers across blood fractions and assay platforms. METHODS: Nonfasting serum and plasma samples from 300 participants (150 AD patients and 150 controls) were analyzed. Proteomic markers were obtained via electrochemiluminescence or Luminex technology. Comparisons were conducted via Pearson correlations. The relative importance of proteins within an AD diagnostic profile was examined using random forest importance plots. RESULTS: On the Meso Scale Discovery multiplex platform, 10 of the 21 markers shared >50% of the variance across blood fractions (serum amyloid A R(2) = 0.99, interleukin (IL)10 R(2) = 0.95, fatty acid-binding protein (FABP) R(2) = 0.94, I309 R(2) = 0.94, IL-5 R(2) = 0.94, IL-6 R(2) = 0.94, eotaxin3 R(2) = 0.91, IL-18 R(2) = 0.87, soluble tumor necrosis factor receptor 1 R(2) = 0.85, and pancreatic polypeptide R(2) = 0.81). When examining protein concentrations across platforms, only five markers shared >50% of the variance (beta 2 microglobulin R(2) = 0.92, IL-18 R(2) = 0.80, factor VII R(2) = 0.78, CRP R(2) = 0.74, and FABP R(2) = 0.70). DISCUSSION: The current findings highlight the importance of considering blood fractions and assay platforms when searching for AD relevant biomarkers.

Cognitive response to estradiol in postmenopausal women is modified by high cortisol.

Estradiol has potent favorable effects on brain function and behavior in animals while in human trials, the results are inconsistent. A number of potential mediating variables influencing response to estradiol have been proposed to account for this variability, 1 of which includes stress. We conducted a placebo-controlled study to examine joint and independent effects of estradiol and elevated levels of the stress hormone cortisol on cognition and biomarkers of aging and neurodegenerative disease. Thirty-nine healthy postmenopausal women (56-84 years) received 0.10 mg/dL of transdermal 17ß-estradiol (E2) or placebo for 8 weeks. During the last 4 days of the trial, subjects also received 90 mg/day (30 mg 3×/day) of oral hydrocortisone (CORT) to induce stress-level elevations in cortisol, or a matched placebo. The 4 groups thus included placebo (placebo patch/placebo pill), CORT-alone (placebo patch/hydrocortisone), E2-alone (estradiol patch/placebo pill), and E2+CORT (estradiol patch/hydrocortisone). Eight weeks of E2 increased plasma estradiol by 167%, and 4 days of CORT increased plasma cortisol by 119%. Overall, E2 had favorable effects on verbal memory (p = 0.03), working memory (p = 0.02), and selective attention (p = 0.04), and the magnitude of these effects was attenuated for E2+CORT. E2-alone and E2+CORT had opposing effects on plasma levels of the amyloid-ß (Aß) biomarker (Aß40/42 ratio, p < 0.05), with the more favorable response observed for E2-alone. CORT-induced increases in insulin-like growth factor-1 were blunted by E2 coadministration. Our findings indicate that cognitive and physiological responses to estradiol are adversely affected by elevated stress hormone levels of cortisol in healthy postmenopausal women.

High-intensity physical activity modulates diet effects on cerebrospinal amyloid-ß levels in normal aging and mild cognitive impairment.

We previously showed that amyloid-ß 1-42 (Aß(42)) levels in cerebrospinal fluid (CSF) were markedly altered in response to a 4-week dietary intervention in normal aging and mild cognitive impairment (MCI). Here, we re-examined the data to assess whether diet-induced effects on CSF Aß(42) were modulated by high intensity physical activity (hi-PA). Normal older adults (n = 18, mean age = 68.6 ± 7.4 y) and adults with amnestic MCI (n = 23, mean age = 68.0 ± 6.5 y) received a low saturated fat/low glycemic index (LOW) diet or a high saturated fat/high glycemic index (HIGH) diet, and CSF levels of Aß(42), tau, and IL-8 were measured at baseline and week 4. Pre-study activity levels were assessed using a 7-d questionnaire, and weekly duration of hi-PA was quantified. At baseline, increased hi-PA in normals predicted lower CSF levels of tau (r = -0.54, p = 0.020) and IL-8 (r = -0.70, p = 0.025). Diet-induced effects on CSF Aß(42) during the intervention study were modulated by hi-PA, and the nature of this effect differed for normals and MCI (ANOVA, p = 0.039). That is, for normal adults, increased hi-PA attenuated the effects of the HIGH diet on CSF Aß(42) whereas in MCI, increased hi-PA potentiated the effects of the LOW diet. Our results suggest that normal adults who engage in hi-PA are less vulnerable to the pathological effects of an unhealthy diet, while in MCI, the benefit of a healthy diet on Aß modulation is greatest when paired with hi-PA. Exercise may thus interact with diet to alter pathological processes that ultimately modify risk of Alzheimer's disease.

Short-term hormone therapy with transdermal estradiol improves cognition for postmenopausal women with Alzheimer's disease: results of a randomized controlled trial.

We aimed to conduct a placebo-controlled, double-blind, parallel-group design intervention study to evaluate the therapeutic efficacy of hormone therapy (HT) in postmenopausal women with mild to moderate Alzheimer's disease (AD). The trial was designed to evaluate the dose-dependent effects of transdermal 17-ß estradiol, unopposed and opposed with medroxyprogesterone (MPA, Provera©), for 12 months in 43 postmenopausal women with AD. Participants were assessed using cognitive measures at baseline, months 1, 3, 6, and 12 of treatment and eight weeks post treatment (month 15). The dropout rate was 49% across 12 months. As a result of the Women's Health Initiative (WHI) and anticipated increased attrition, the protocol was modified to examine data only at time points where attrition was less than 30%. The results of sensitivity analyses indicated robust and reliable data collected in the first three months of the trial. Data collected in the first three months of the trial for forty-three participants were analyzed. HT had favorable cognitive effects across multiple cognitive domains, including visual memory (p-values < 0.030) and semantic memory (p-values < 0.037) in postmenopausal women with AD. Moreover, treatment-related changes in plasma estradiol were positively correlated with improvements in visual memory. Short-term HT that includes the use of estradiol has favorable effects on cognition in women with AD.

Hyperinsulinemia provokes synchronous increases in central inflammation and beta-amyloid in normal adults.

BACKGROUND: Inflammation has been implicated as a pathogenetic factor in Alzheimer disease, possibly via effects on beta-amyloid (Abeta). Hyperinsulinemia induces inflammation and is a risk factor for Alzheimer disease. Thus, insulin abnormalities may contribute to Alzheimer disease pathophysiology through effects on the inflammatory network. OBJECTIVES: To determine the effects of induced hyperinsulinemia with euglycemia on Abeta, transthyretin, and inflammatory markers and modulators in plasma and cerebrospinal fluid (CSF). DESIGN: Randomized crossover trial. SETTING: Veterans Affairs hospital clinical research unit. PARTICIPANTS: Sixteen healthy adults ranging from 55 to 81 years of age (mean age, 68.2 years). INTERVENTIONS: On separate mornings, fasting participants received randomized infusions of saline or insulin (1.0 mU.kg(-1).min(-1)) with variable dextrose levels to maintain euglycemia, achieving plasma insulin levels typical of insulin resistance. Plasma and CSF were collected after an approximately 105-minute infusion. MAIN OUTCOME MEASURES: Plasma and CSF levels of interleukin 1alpha, interleukin 1beta, interleukin 6, tumor necrosis factor alpha, F2-isoprostane (CSF only), Abeta, norepinephrine, transthyretin, and apolipoprotein E. RESULTS: Insulin increased CSF levels of F2-isoprostane and cytokines (both P<.01), as well as plasma and CSF levels of Abeta42 (both P<.05). The changes in CSF levels of Abeta42 were predicted by increased F2-isoprostane and cytokine levels (both P<.01) and reduced transthyretin levels (P = .02). Increased inflammation was modulated by insulin-induced changes in CSF levels of norepinephrine and apolipoprotein E (both P<.05). CONCLUSION: Moderate hyperinsulinemia can elevate inflammatory markers and Abeta42 in the periphery and the brain, thereby potentially increasing the risk of Alzheimer disease.

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1/mac 25) is reduced in human prostate cancer and is inversely related to tumor volume and proliferation index in Lucap 23.12 xenografts.

BACKGROUND: In the prostate, insulin-like growth factor binding protein-related protein-1 (IGFBP-rP1/mac 25) appears to be decreased in cancer. Likewise, mice injected with prostate cells over-expressing IGFBP-rP1/mac 25 showed decreased tumor formation and tumor volume. METHODS: Immunohistochemistry was used to determine the presence of IGFBP-rP1/mac 25 in human prostate tissue and in LuCaP 23.12 prostate cancer xenografts. RESULTS: Immunoreactivity for IGFBP-rP1/mac 25 was detected in the cytoplasm and nuclei of benign prostate epithelium. Cancer cells also stained but the level of intensity was less than that observed in benign epithelium (P < 0.05). Within the stroma, peripheral nerves, and endothelial vessels reacted with IGFBP-rP1/mac 25 antibodies. IGFBP-rP1/mac 25 was also observed in the nuclei of LuCaP 23.12 cells. LuCaP xenografts with smaller tumor volumes demonstrated more staining, and larger tumor volumes had less staining (P = 0.0033, R = 0.610). There was also a significant inverse correlation between IGFBP-rP1/mac 25 levels in LuCaP 23.12 cells and the proliferative index, measured by percent of cells staining for 5-bromo-2'-deoxyuridine (Br-dU) (P = 0.0045, R = 0.594). CONCLUSIONS: IGFBP-rP1/mac 25 is present in normal prostate epithelium and is decreased in human prostate malignancy and higher IGFBP-rP1/mac 25 levels are associated with reduced tumor growth.

17beta-estradiol reduces plasma Abeta40 for HRT-naïve postmenopausal women with Alzheimer disease: a preliminary study.

OBJECTIVE: One mechanism to support the potentially beneficial effects of estrogen in the brain for postmenopausal women potentially involves the hormone's ability to favorably alter the processing of amyloid-precursor protein (APP), believed to play an important role in the pathobiology of Alzheimer disease (AD). The authors evaluated the effects of estrogen administration on plasma concentration of one by-product of APP processing, Abeta40, for postmenopausal women with AD. METHODS: In a placebo-controlled, double blind, parallel-group design study, 20 women were randomized to receive either 0.10 mg/day of transdermal 17beta-estradiol or a placebo for 8 weeks and were retrospectively evaluated as to whether basal levels of Abeta40 were affected by pre-study use of hormone replacement therapy (HRT). Blood samples were collected and cognitive tests were administered at baseline; at Weeks 3, 5, and 8 during treatment; and again 8 weeks after treatment termination. RESULTS: For the group as a whole, plasma Abeta40 was not reliably reduced in response to short-term estradiol administration. For HRT-naïve subjects, baseline Abeta40 concentrations were higher than those of previous HRT users, and controlled estradiol administration significantly reduced plasma Abeta40 by the end of the 8-week treatment period. CONCLUSIONS: These results provide preliminary clinical evidence to support an effect of estradiol on Abeta-processing for AD women who are HRT-naïve. This finding suggests that the hormone may serve as an Abeta-lowering agent for HRT-naïve AD women, which may, in turn, have ultimate ramifications for the progression of AD pathology.

Estrogen and Alzheimer's disease: the story so far.

The ovarian hormone estrogen has long been used to treat the physical symptoms of menopause and to aid in the prevention of osteoporosis in postmenopausal women. Cumulative evidence from basic science and clinical research suggests that estrogen also plays a significant neuromodulatory and neuroprotective role. The numerous estrogenic effects in the brain include the modulation of synaptogenesis, increased cerebral blood flow, mediation of important neurotransmitters and hormones, protection against apoptosis, anti-inflammatory actions, and antioxidant properties. These multiple actions in the central nervous system support estrogen as a potential treatment for the cognitive decline associated with Alzheimer's disease (AD), the most common form of dementia. Evidence from epidemiological studies supports enhanced cognitive function in women with AD taking estrogen replacement therapy (ERT) as well as a reduced risk for developing AD in healthy women receiving ERT. Additional clinical evidence suggests that estrogen may modulate specific cognitive functions such as working memory and verbal learning and memory. However, results from more recent controlled trials have not consistently shown a beneficial effect of estrogen on the cognitive function of women with AD. Future research should focus on examining the influence of multiple potential mediators of ERT including the route of estrogen administration, form of estrogen (conjugated estrogens vs estradiol), duration of treatment, opposed versus unopposed estrogen and the use of estrogen analogues. Further, sensitive neuropsychological measures may provide more detailed information concerning the specific effects of estrogen on cognitive function. These important issues must be addressed in order to establish the role of estrogen for the prevention and treatment of AD in women.