Statin therapy and risk of dementia in the elderly: a community-based prospective cohort study

The Association Between Cardiovascular Disease and Dementia: A Review of Trends in Epidemiology, Risk Factors, Pathophysiologic Mechanisms, and Clinical Implications

With increases in life expectancy and the size of the aging population, cognitive decline and neurodegenerative pathologies are expected to increase in the next few decades. Age-related increases in risk for dementia and cardiovascular disease have been researched widely. Epidemiology trends reveal a predicted increase of neurodegenerative disease to more than 65 million by 2030 in the United States. There are several risk factors for the development of cardiovascular disease that have been widely studied for their impact on dementia; such as: diabetes, hypertension, and hyperlipidemia. Several pathophysiologic mechanisms exist by which cardiovascular disease could impact dementia including cerebral hypoperfusion, reactive oxidative species, and increased cleavage of amyloid precursor protein into amyloid beta plaques and accumulation of neurofibrillary tangles. Emerging evidence also suggests that treatment of cardiovascular disease risk factors could reduce the risk of dementia development. In this review, we seek to examine the relationship between cardiovascular disease and dementia by examining epidemiologic trends, common risk factors, pathophysiologic mechanisms and implications for clinical management.

Protective Effects Against Dementia Undergo Different Statin Type, Intensity, and Cumulative Dose in Older Adult Type 2 Diabetes Mellitus Patients

OBJECTIVES

This study investigated the relationship between statin use and dementia risk in older adults with type 2 diabetes (T2DM). It also assessed the impact of various statin types, dosage intensity, and cumulative doses on dementia risk.

DESIGN

Employing the inverse probability of treatment weighting (IPTW) Cox hazards model, this research explored the influence of statin utilization on dementia incidence.

SETTING AND PARTICIPANTS

The study included older adult T2DM patients aged 60 years or older who received statins (case group) and those who did not (control group) during the follow-up period.

METHODS

The IPTW Cox hazards model quantified the association between statin use and dementia incidence. Subgroup analyses investigated different statin types, usage intensity, and cumulative dose-dependent relationships with dementia risk, measured by adjusted hazard ratios (aHRs) with corresponding 95% CIs.

RESULTS

Statin users experienced a significant reduction in dementia risk (aHR: 0.47, 95% CI: 0.46-0.48). Subgroup analysis using IPTW Cox regression revealed varying dementia incidence reductions among users of different statin types, with aHRs (95% CIs) ranging from 0.09 to 0.69. Multivariate analyses unveiled a dose-dependent relationship, showing reduced dementia incidence based on cumulative defined daily doses (cDDDs) per year. The corresponding aHRs (95% CIs) were 0.20 to 0.72 across quartiles 4 to 1 of cDDD-years, with a significant trend (P < .001). The optimal daily statin use was 0.88 defined daily doses (DDDs), associated with the lowest dementia risk.

CONCLUSIONS AND IMPLICATIONS

Statins significantly reduced dementia risk in older adult T2DM patients. Higher cumulative defined daily doses (cDDD-years) were linked to more substantial risk reductions. This research underscores the clinical benefits of statin use in preventing dementia in this population and calls for further investigation into the underlying mechanisms. It also raises the possibility of influencing policy decisions to manage dementia risk in this vulnerable group.

Association of Statin Use with Dementia Risk Among Older Adults in Japan: A Nested Case-Control Study Using the LIFE Study

Background

Previous studies have shown a possible association between statin use and a decreased risk of dementia, but the association has not been sufficiently established, especially in the super-aging society of Japan.

Objective

This study aimed to determine the association between statin use and the risk of dementia among Japanese participants aged> =65 years old.

Methods

Data from the Longevity Improvement and Fair Evidence (LIFE) Study were utilized, including medical and long-term care (LTC) claim data from 17 municipalities between April 2014 and December 2020. A nested case-control study was conducted with one case matched to five controls based on age, sex, municipality, and year of cohort entry. We used a conditional logistic regression model to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs).

Results

This study included 57,302 cases and 283,525 controls, with 59.7% of the participants being woman. After adjusting for potential confounders, statin use was associated with a lower risk of dementia (OR, 0.70; 95% CI: 0.68-0.73) and Alzheimer's disease (OR: 0.66; 95% CI: 0.63-0.69). Compared with non-users, the ORs of dementia were as follows: 1.42 (1.34-1.50) for 1-30 total standardized daily dose (TSDD), 0.91 (0.85-0.98) for 31-90 TSDD, 0.63 (0.58-0.69) for 91-180 TSDD, and 0.33 (0.31-0.36) for >180 TSDD in dose-analysis.

Conclusions

Statin use is associated with a reduced risk of dementia and Alzheimer's disease among older Japanese adults. A low cumulative statin dose is associated with an increased risk of dementia, whereas a high cumulative statin dose is a protective factor against dementia.

Effects of multimodal cognitive exercise program on cognitive function, bone density, blood lipid, fitness, and depression in old women with mild cognitive impairment

The purpose of this study is to verify the effects of participation in 12-week multimodal cognitive exercise program on cognitive function, bone mineral density, blood lipids, senior functional fitness, and depression of the old women with mild cognitive impairment and osteopenia. As a result, the exercise group showed significant effects in cognitive function, depression, bone mineral density, blood lipid, lower extremity flexibility, upper extremity flexibility, dynamic balance, and body endurance. Such results prove that multimodal cognitive exercise program is an effective interventional exercise program for improving cognitive function in the old women with mild cognitive impairment.

Statin use and risk of dementia or Alzheimer's disease: a systematic review and meta-analysis of observational studies

AIMS

As the potential impact of statins on cognitive decline and dementia is still debated, we conducted a meta-analysis of observational studies to examine the effect of statin use on the risk of Alzheimer's disease (AD) and dementia.

METHODS AND RESULTS

PubMed, Cochrane, and EMBASE were searched since inception to January 2021. Inclusion criteria were: (i) cohort or case-control studies; (ii) statin users compared to non-users; and (iii) AD and/or dementia risk as outcome. Estimates from original studies were pooled using restricted maximum-likelihood random-effect model. Measure of effects were reported as odds ratio (OR) and 95% confidence intervals (CIs). In the pooled analyses, statins were associated with a decreased risk of dementia [36 studies, OR 0.80 (CI 0.75-0.86)] and of AD [21 studies, OR 0.68 (CI 0.56-0.81)]. In the stratified analysis by sex, no difference was observed in the risk reduction of dementia between men [OR 0.86 (CI 0.81-0.92)] and women [OR 0.86 (CI 0.81-0.92)]. Similar risks were observed for lipophilic and hydrophilic statins for both dementia and AD, while high-potency statins showed a 20% reduction of dementia risk compared with a 16% risk reduction associated with low-potency statins, suggesting a greater efficacy of the former, although a borderline statistical significance (P = 0.05) for the heterogeneity between estimates.

CONCLUSION

These results confirm the absence of a neurocognitive risk associated with statin treatment and suggest a potential favourable role of statins. Randomized clinical trials with an ad hoc design are needed to explore this potential neuroprotective effect.

Association Between Low-Density Lipoprotein Cholesterol Levels, Statin Use, and Dementia in Patients followed in German General Practices

BACKGROUND

No studies have been conducted to date on the association between low-density lipoprotein cholesterol (LDL-C), statin use classified into low, medium, and high statin dosages, and dementia in German general practices.

OBJECTIVE

The goal of this retrospective case-control study was to investigate the relationship between elevated LDL-C, statins, and dementia in elderly persons followed in general practices in Germany.

METHODS

This study included patients aged 65 or older with an initial dementia diagnosis between January 2015 and December 2019 and at least one documented LDL-C value within the year prior to the dementia diagnosis. These patients were treated in one of 963 general practices which document LDL-C in Germany. Dementia cases were matched to non-dementia controls using propensity scores based on age, sex, and comorbidities. Logistic regression models were conducted to assess a possible association between accelerated LDL-C, statins, and dementia.

RESULTS

The study included 12,236 patients with dementia and 12,236 non-dementia controls. In total, 2,528 of the dementia patients were diagnosed with vascular dementia. The use of all dosages of statin use was negatively associated with all-cause dementia (OR: 0.80 for low dose, OR: 0.92 for medium dose, and OR: 0.85 for high dose) and with vascular dementia (OR: 0.61 for low dose, OR: 0.77 for medium dose, and OR: 0.74 for high dose). There was no clinically relevant association between elevated LDL-C and dementia.

CONCLUSION

A negative association was found between all dosage use of statin therapy and all-cause dementia and vascular dementia in elderly patients in general practices in Germany.

Fine Particulate Matter and Dementia Incidence in the Adult Changes in Thought Study

BACKGROUND

Air pollution may be associated with elevated dementia risk. Prior research has limitations that may affect reliability, and no studies have evaluated this question in a population-based cohort of men and women in the United States.

OBJECTIVES

We evaluated the association between time-varying, 10-y average fine particulate matter (PM2.5) exposure and hazard of all-cause dementia. An additional goal was to understand how to adequately control for age and calendar-time-related confounding through choice of the time axis and covariate adjustment.

METHODS

Using the Adult Changes in Thought (ACT) population-based prospective cohort study in Seattle, we linked spatiotemporal model-based PM2.5 exposures to participant addresses from 1978 to 2018. Dementia diagnoses were made using high-quality, standardized, consensus-based protocols at biennial follow-ups. We conducted multivariable Cox proportional hazards regression to evaluate the association between time-varying, 10-y average PM2.5 exposure and time to event in a model with age as the time axis, stratified by apolipoprotein E (APOE) genotype, and adjusted for sex, education, race, neighborhood median household income, and calendar time. Alternative models used calendar time as the time axis.

RESULTS

We report 1,136 cases of incident dementia among 4,166 individuals with nonmissing APOE status. Mean [mean ± standard deviation (SD)] 10-y average PM2.5 was 10.1 (±2.9) μg/m3. Each 1-μg/m3 increase in the moving average of 10-y PM2.5 was associated with a 16% greater hazard of all-cause dementia [1.16 (95% confidence interval: 1.03, 1.31)]. Results using calendar time as the time axis were similar.

DISCUSSION

In this prospective cohort study with extensive exposure data and consensus-based outcome ascertainment, elevated long-term exposure to PM2.5 was associated with increased hazard of all-cause dementia. We found that optimal control of age and time confounding could be achieved through use of either age or calendar time as the time axis in our study. Our results strengthen evidence on the neurodegenerative effects of PM2.5. https://doi.org/10.1289/EHP9018.

Association between statin use and Alzheimer's disease with dose response relationship

This study aimed to determine the dose-response relationship between the levels of statin exposure and the incidence of Alzheimer's disease (AD). We included 119,013 Korean adults (≥ 60 years old) using a database from the Korean National Health Insurance Service (2002-2013). Statin exposure was treated as a time-varying variable. Incidence of AD was defined by the first claim code for AD with anti-Alzheimer drugs. AD occurred in 9467 cases during a median 7.2 years of follow-up. Overall, statin use was not associated with an increased risk of AD incidence [adjusted hazard ratio (aHR) = 1.04; 95% confidence interval (CI) = 0.99-1.10]. When examined by level of statin exposure, statin prescription < 540 days during a 2-year window time was associated with a higher risk for incidence of AD compared to statin non-use. However, days of prescription ≥ 540 and cumulative defined daily dose ≥ 540 of statin were associated with decreased risk of AD [aHR (95% CI) = 0.87 (0.80-0.95) and 0.79 (0.68-0.92), respectively]. Our findings indicate that less persistent statin use is associated with increased risk of AD, whereas persistent and adherent statin use is associated with decreased risk of AD.

Association between statin use and cognitive function: A systematic review of randomized clinical trials and observational studies

The US Food and Drug Administration issued a black box warning in 2012 regarding the association of statin use with cognitive impairment. This may deter patients and practitioners from using statins for guideline-directed indications. Large studies have not shown an increase in cognitive impairment with statin use. MEDLINE, EMBASE, and Cochrane databases were searched up to October 2019. We present an up-to-date systematic review of randomized controlled trials (RCTs) and prospective observational studies examining the association between statin use and cognitive status in a population aged ≥60 years. Twenty-four studies with 1,404,459 participants were included in the review. Twenty-one were prospective observational studies, and 3 were RCTs. All 3 RCTs, which ranged from 3.2 to 5.6 years of follow-up, showed no significant association between statin use and adverse cognitive effects (odds ratio [OR] 1.03 [0.82-1.30]) and (OR 1.0 [0.61-1.65]). The mean difference in the Mini-Mental State Examination was insignificant (0.06 [-0.04 to 0.16]) in the third RCT. The follow-up for observational studies ranged from 3 to 15 years. Ten observational studies showed reduced incidence of dementia. Seven showed no association with incident dementia. Three studies showed decline in cognition was similar, whereas one showed slower decline with statin use. There was no evidence of adverse cognitive effects, including incidence of dementia, deterioration in global cognition, or specific cognitive domains associated with statin use in individuals aged ≥60 years. Future studies should examine this association in studies with longer follow-up periods.

Blood Lipids and Cognitive Performance of Aging Polish Adults: A Case-Control Study Based on the PolSenior Project

Background: The demand for effective strategies for maintaining cognitive capableness and establishing early dementia diagnosis has been tremendous, especially in the context of population aging. However, studies on the elderly population and neurocognitive impairment had provided ambiguous results throughout, while potential blood biomarkers of cognitive decline are yet to be clearly understood.

Objectives: The present study is aimed at assessing the relationship between blood lipids—especially in the context of their usefulness as biomarkers of an early cognitive decline—and cognitive functioning of aging adults.

Materials and Methods: The study sample consisted of 230 participants—(109 women, 121 men) aged 65+ years. Plasma 24(S)-hydroxycholesterol [24(S)-OHC], serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) were assessed. The analyses were conducted in three groups of cognitive performance: cognitively normal, mild cognitive impairment (MCI), and mild dementia, of which the subjects were divided with the Mini-Mental State Examination (MMSE).

Results: No significant differences in 24(S)-OHC plasma concentrations for different levels of cognitive performance were found. Significant differences were found in serum TC (p = 0.026) and LDL (p = 0.007) concentrations for different levels of cognitive performance. Concentrations of both parameters were highest in the MCI group and lowest in mild dementia and cognitive norm, respectively. No significant differences between serum HDL concentrations and cognitive performance were found.

Conclusions: To fully assess the potential of research on blood lipids in regards to a cognitive decline, cross-sectional or epidemiological studies aimed at further exploring blood lipid roles in both the early and advanced MCI and dementia, are needed.

Emulating a target trial of statin use and risk of dementia using cohort data

OBJECTIVE

Observational data can be used to attempt to emulate a target trial of statin use and estimate analogues of intention-to-treat and per protocol effects on dementia risk.

METHODS

Using data from a prospective cohort study in the Netherlands, we conceptualized a sequence of "trials" in which eligible individuals ages 55-80 years were classified as statin initiators or noninitiators for every consecutive month between 1993 and 2007 and were followed until diagnosis of dementia, death, loss to follow-up, or the end of follow-up. We estimated 2 types of effects of statin use on dementia and a combined endpoint of dementia or death: the effect of initiation vs no initiation and the effect of sustained use vs no use. We estimated risk by statin treatment strategy over time via pooled logistic regression. We used inverse-probability weighting to account for treatment-confounder feedback in estimation of per-protocol effects.

RESULTS

Of 233,526 eligible person-trials (6,373 individuals), there were 622 initiators and 232,904 noninitiators. Comparing statin initiation with no initiation, the 10-year risk differences (95% confidence interval) were -0.1% (-2.3% to 1.8%) for dementia and 0.3% (-2.7% to 3.3%) for dementia or death. Comparing sustained statin use vs no use, the 10-year risk differences were -2.2% (-5.2% to 1.6%) for dementia and -5.1% (-10.5% to -1.1%) for dementia or death.

CONCLUSIONS

Individuals with sustained statin use, but not statin initiation alone, had reduced 10-year risks of dementia and dementia or death. Our results should be interpreted with caution due to the small number of initiators and events and potential for residual confounding.

Emerging roles for high-density lipoproteins in neurodegenerative disorders

Lipoproteins are the complexes of different lipids and proteins, which are devoted to the transport and clearance of lipids or lipid-related molecules in the circulation. Lipoproteins have been found to play a crucial role in brain function and may influence myelination process. Among lipoproteins, high-density lipoproteins (HDLs) and their major protein component, apoA-I, are directly involved in cholesterol efflux in the brain. It has been suggested that inadequate or dysfunctional brain HDLs may contribute to cerebrovascular dysfunctions, neurodegeneration, or neurovascular instability. HDL deficiency could also promote cognitive decline through impacting on atherosclerotic risk. The focus of this review is to discuss knowledge on HDL dysregulation in neurological disorders. A better understanding on how changes in cellular HDL and apolipoprotein homeostasis affect central nervous system function may provide promising novel avenues for the treatment of specific HDL-related neurological disorders.

Does Treating Vascular Risk Factors Prevent Dementia and Alzheimer's Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Epidemiological evidence has associated Alzheimer's disease (AD) with vascular risk factors (VRFs), but whether treatment of VRFs reduces the incidence of dementia and AD is uncertain.

OBJECTIVE

To conduct a systematic review and meta-analysis to summarize available data on the impact of treatment of VRFs on dementia and AD incidence.

METHODS

Pertinent studies published until 1 January 2018 were identified from PubMed. Both randomized controlled trials (RCT) and prospective studies that investigated the impact of treatment of VRFs on dementia or AD incidence were included.

RESULTS

Eight RCTs and 52 prospective studies were identified. Antihypertensive treatment was associated with a non-significant reduced risk of dementia in RCTs (n = 5; relative risk [RR], 0.84; 95% confidence interval [CI], 0.69-1.02) and prospective studies (n = 3; RR, 0.77; 95% CI, 0.58-1.01) and with reduced AD risk in prospective studies (n = 5; RR = 0.78; 95% CI, 0.66-0.91). In prospective studies, treatment of hyperlipidemia with statins, but not nonstatin lipid-lowering agents, was associated with reduced risk of dementia (n = 17; RR, 0.77; 95% CI, 0.63-0.95) and AD (n = 13; RR, 0.86; 95% CI, 0.80-0.92). The single RCT on statins and dementia incidence showed no association. Data from one RCT and six prospective studies did not support a beneficial impact of antidiabetic drugs or insulin therapy on dementia risk.

CONCLUSION

Current evidence indicates that antihypertensives and statins might reduce the incidence of dementia and AD. Further trials to determine the effect of VRF on AD are needed.

Statins and the Brain: More than Lipid Lowering Agents?

BACKGROUND

Statins represent a class of medications widely prescribed to efficiently treat dyslipidemia. These drugs inhibit 3-βhydroxy 3β-methylglutaryl Coenzyme A reductase (HMGR), the rate-limiting enzyme of mevalonate (MVA) pathway. Besides cholesterol, MVA pathway leads to the production of several other compounds, which are essential in the regulation of a plethora of biological activities, including in the central nervous system. For these reasons, statins are able to induce pleiotropic actions, and acquire increased interest as potential and novel modulators in brain processes, especially during pathological conditions.

OBJECTIVE

The purpose of this review is to summarize and examine the current knowledge about pharmacokinetic and pharmacodynamic properties of statins in the brain. In addition, effects of statin on brain diseases are discussed providing the most up-to-date information.

METHODS

Relevant scientific information was identified from PubMed database using the following keywords: statins and brain, central nervous system, neurological diseases, neurodegeneration, brain tumors, mood, stroke.

RESULTS

315 scientific articles were selected and analyzed for the writing of this review article. Several papers highlighted that statin treatment is effective in preventing or ameliorating the symptomatology of a number of brain pathologies. However, other studies failed to demonstrate a neuroprotective effect.

CONCLUSION

Even though considerable research studies suggest pivotal functional outcomes induced by statin therapy, additional investigation is required to better determine the pharmacological effectiveness of statins in the brain, and support their clinical use in the management of different neuropathologies.

Statin use and delayed onset of Huntington's disease

BACKGROUND

There is evidence to suggest that 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) may be beneficial in Huntington's disease (HD).

OBJECTIVE

This study aimed to determine if statin use was associated with delayed motor diagnosis in participants with premotor HD.

METHODS

Among premotor HD participants from the Enroll-HD database, statin users were propensity score matched with statin nonusers based on cytosine-adenine-guanine-age product score, cytosine-adenine-guanine repeat length, baseline age, sex, and region. A Cox regression survival analysis compared the annualized hazard ratio (HR) of receiving a motor diagnosis between the 2 groups.

RESULTS

The annualized HR of progressing to an HD motor diagnosis was lower in the statin users (n = 89) when compared with the statin nonusers (n = 89; HR = 0.27 [95% CI 0.18-0.50], P < .0001).

CONCLUSIONS

In patients with premotor HD, statin use was associated with a delayed motor diagnosis of HD. Further studies are warranted to investigate if statins would be an effective disease-modifying therapy for HD. © 2018 International Parkinson and Movement Disorder Society.

Connecting the brain cholesterol and renin-angiotensin systems: potential role of statins and RAS-modifying medications in dementia

Millions of people worldwide receive agents targeting the renin-angiotensin system (RAS) to treat hypertension or statins to lower cholesterol. The RAS and cholesterol metabolic pathways in the brain are autonomous from their systemic counterparts and are interrelated through the cholesterol metabolite 27-hydroxycholesterol (27-OHC). These systems contribute to memory and dementia pathogenesis through interference in the amyloid-beta cascade, vascular mechanisms, glucose metabolism, apoptosis, neuroinflammation and oxidative stress. Previous studies examining the relationship between these treatments and cognition and dementia risk have produced inconsistent results. Defining the blood-brain barrier penetration of these medications has been challenging, and the mechanisms of action on cognition are not clearly established. Potential biases are apparent in epidemiological and clinical studies, such as reverse epidemiology, indication bias, problems defining medication exposure, uncertain and changing doses, and inappropriate grouping of outcomes and medications. This review summarizes current knowledge of the brain cholesterol and RAS metabolism and the mechanisms by which these pathways affect neurodegeneration. The putative mechanisms of action of statins and medications inhibiting the RAS will be examined, together with prior clinical and animal studies on their effects on cognition. We review prior epidemiological studies, analysing their strengths and biases, and identify areas for future research. Understanding the pathophysiology of the brain cholesterol system and RAS and their links to neurodegeneration has enormous potential. In future, well-designed epidemiological studies could identify potential treatments for Alzheimer's disease (AD) amongst medications that are already in use for other indications.

Statins use and risk of dementia: A dose-response meta analysis

Previous studies have indicated that statins use is associated with risk of dementia, but presented controversial results. Medline, Embase, Web of Science, and the Cochrane Database were searched update to November 2017 to identify the potential relationship between statins use and dementia. Thirty-one eligible studies involving a total of 3332,706 participants with 184,666 incident cases were included in this meta-analysis. Statins use was associated with dementia risk decrement (relevant risk [RR]: 0.85; 95% confidence interval [CI], 0.80-0.89). Subgroup analysis showed statins use was associated with Alzheimer disease (AD) (RR: 0.81; 95% CI, 0.73-0.89) and non-AD dementia (RR: 0.81; 95% CI, 0.73-0.89) risk decrement. Furthermore, statins use was associated with dementia risk decrement in female (RR: 0.89; 95% CI, 0.80-0.98) and male (RR: 0.88; 95% CI, 0.83-0.93). In addition, a dose-response showed per 1 year of duration of statins use incremental increase was associated with 20% dementia risk decrement (RR: 0.80; 95% CI, 0.73-0.87), and per 5-mg mean daily dose incremental increase in statins use was associated with 11% dementia risk decrement (RR: 0.89; 95% CI, 0.83-0.96). Statins use was associated with dementia risk decrement. The potency and the cumulative duration of statin utilized played critical roles.

Use of statins and the risk of dementia and mild cognitive impairment: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to investigate whether the use of statins could be associated with the risk of all-caused dementia, Alzheimer’s disease (AD), vascular dementia (VaD), and mild cognitive impairment (MCI). Major electronic databases were searched until December 27^th, 2017 for studies investigating use of statins and incident cognitive decline in adults. Random-effects meta-analyses calculating relative risks (RRs) were conducted to synthesize effect sizes of individual studies. Twenty-five studies met eligibility criteria. Use of statins was significantly associated with a reduced risk of all-caused dementia (k = 16 studies, adjusted RR (aRR) = 0.849, 95% CI = 0.787–0.916, p = 0.000), AD (k = 14, aRR = 0.719, 95% CI = 0.576–0.899, p = 0.004), and MCI (k = 6, aRR = 0.737, 95% CI = 0.556–0.976, p = 0.033), but no meaningful effects on incident VaD (k = 3, aRR = 1.012, 95% CI = 0.620–1.652, p = 0.961). Subgroup analysis suggested that hydrophilic statins were associated with reduced risk of all-caused dementia (aRR = 0.877; CI = 0.818–0.940; p = 0.000) and possibly lower AD risk (aRR = 0.619; CI = 0.383–1.000; p = 0.050). Lipophilic statins were associated with reduced risk of AD (aRR = 0.639; CI = 0.449–0.908; p = 0.013) but not all-caused dementia (aRR = 0.738; CI = 0.475–1.146; p = 0.176). In conclusion, our meta-analysis suggests that the use of statins may reduce the risk of all-type dementia, AD, and MCI, but not of incident VaD.

Statin-Associated Side Effects

Hydroxy-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors or statins are well tolerated, but associated with various statin-associated symptoms (SAS), including statin-associated muscle symptoms (SAMS), diabetes mellitus (DM), and central nervous system complaints. These are "statin-associated symptoms" because they are rare in clinical trials, making their causative relationship to statins unclear. SAS are, nevertheless, important because they prompt dose reduction or discontinuation of these life-saving mediations. SAMS is the most frequent SAS, and mild myalgia may affect 5% to 10% of statin users. Clinically important muscle symptoms, including rhabdomyolysis and statin-induced necrotizing autoimmune myopathy (SINAM), are rare. Antibodies against HMG-CoA reductase apparently provoke SINAM. Good evidence links statins to DM, but evidence linking statins to other SAS is largely anecdotal. Management of SAS requires making the possible diagnosis, altering or discontinuing the statin treatment, and using alternative lipid-lowering therapy.

Accelerated failure time models for semi-competing risks data in the presence of complex censoring

Statistical analyses that investigate risk factors for Alzheimer's disease (AD) are often subject to a number of challenges. Some of these challenges arise due to practical considerations regarding data collection such that the observation of AD events is subject to complex censoring including left-truncation and either interval or right-censoring. Additional challenges arise due to the fact that study participants under investigation are often subject to competing forces, most notably death, that may not be independent of AD. Towards resolving the latter, researchers may choose to embed the study of AD within the "semi-competing risks" framework for which the recent statistical literature has seen a number of advances including for the so-called illness-death model. To the best of our knowledge, however, the semi-competing risks literature has not fully considered analyses in contexts with complex censoring, as in studies of AD. This is particularly the case when interest lies with the accelerated failure time (AFT) model, an alternative to the traditional multiplicative Cox model that places emphasis away from the hazard function. In this article, we outline a new Bayesian framework for estimation/inference of an AFT illness-death model for semi-competing risks data subject to complex censoring. An efficient computational algorithm that gives researchers the flexibility to adopt either a fully parametric or a semi-parametric model specification is developed and implemented. The proposed methods are motivated by and illustrated with an analysis of data from the Adult Changes in Thought study, an on-going community-based prospective study of incident AD in western Washington State.

Relationship between plasma lipids and mild cognitive impairment in the elderly Chinese: a case-control study

Background

High lipid levels may constitute a more important risk factor for cognitive health in previous studies. However, the association of plasma lipids with mild cognitive impairment (MCI) among elderly people had not been studied exactly. This study aims to explore the relationship between plasma lipids/lipoproteins and the risk of MCI in elderly Chinese individuals.

Methods

CSI-MCI study was a preliminary case-control study of the association of plasma lipids/lipoproteins with MCI in 112 MCI cases and 115 cognitively normal controls. Plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) levels were measured in fasting blood samples. Multivariable logistic regression was used to evaluate the potential association between MCI and these factors. Statistical models were adjusted for multiple demographic and biological covariates.

Results

The subjects with MCI were significantly older, higher percentage of females and less educated than controls (P <0.05). As expected, subjects with MCI had lower MMSE score compared with controls (P <0.05). Multivariate logistic regression analysis showed that higher plasma TC level was associated with the risk of MCI in models adjusting for age, sex and education. However, This association was attenuated after adjusting for BMI, Type 2 diabetes mellitus, heart disease and hypertension. Plasma TG level was negatively associated with the risk of MCI. The adjusted odds ratio (OR) of MCI was significantly reduced for the highest quartile of plasma TG level (OR: 0.76, 95 % CI: 0.48–0.97), but not for the second or third quartile, compared with the lowest quartile (adjusted models). Plasma HDL level was significantly negatively associated with the risk of MCI. There was no association between plasma LDL level and the risk of MCI, adjustment for demographics, vascular disorders did not change this relation.

Conclusions

Plasma TC was significantly higher in MCI subjects compared to cognitively normal controls, Elevated plasma HDL and triglyceride were associated with the occurrence of MCI. These findings need to be confirmed in further longitudinal studies.

Towards onset prevention of cognition decline in adults with Down syndrome (The TOP-COG study): A pilot randomised controlled trial

BACKGROUND

Dementia is very common in Down syndrome (trisomy 21) adults. Statins may slow brain amyloid β (Aβ, coded on chromosome 21) deposition and, therefore, delay Alzheimer disease onset. One prospective cohort study with Down syndrome adults found participants on statins had reduced risk of incident dementia, but there are no randomised controlled trials (RCTs) on this issue. Evidence is sparse on the best instruments to detect longitudinal cognitive decline in older Down syndrome adults.

METHODS

TOP-COG was a feasibility/pilot, double-blind RCT of 12 months simvastatin 40 mg versus placebo for the primary prevention of dementia in Alzheimer disease in Down syndrome adults aged 50 years or older. Group allocation was stratified by age, apolipoprotein E (APOE) ε4 allele status, and cholesterol level. Recruitment was from multiple general community sources over 12 months. Adults with dementia, or simvastatin contraindications, were excluded. Main outcomes were recruitment and retention rates. Cognitive decline was measured with a battery of tests; secondary measures were adaptive behaviour skills, general health, and quality of life. Assessments were conducted pre randomisation and at 12 months post randomisation. Blood Aβ40/Aβ42 levels were investigated as a putative biomarker. Results were analysed on an intention-to-treat basis. A qualitative sub-study was conducted and analysed using the Framework Approach to determine recruitment motivators/barriers, and participation experience.

RESULTS

We identified 181 (78 %) of the likely eligible Down syndrome population, and recruited 21 (11.6 %), from an area with a general population size of 3,135,974. Recruitment was highly labour-intensive. Thirteen (62 %) participants completed the full year. Results favoured the simvastatin group. The most appropriate cognitive instrument (regarding ease of completion and detecting change over time) was the Memory for Objects test from the Neuropsychological Assessment of Dementia in Individuals with Intellectual Disabilities battery. Cognitive testing appeared more sensitive than proxy-rated adaptive behaviour, quality of life, or general health scores. Aβ40 levels changed less for the simvastatin group (not statistically significant). People mostly declined to participate because of not wanting to take medication, and not knowing if they would receive simvastatin or placebo. Participants reported enjoying taking part.

CONCLUSION

A full-scale RCT is feasible. It will need 37 % UK population coverage to recruit the required 160 participants. Information/education about the importance of RCT participation is needed for this population.

TRIAL REGISTRATION

ISRCTN67338640 .

Association between APOE ε4 Genotype and Memory Impairment in Elderly with Normal Global Cognitive Assessment

Aim: Early prediction using cognitive evaluation tools that are less influenced by education level is beneficial for dementia screening. This study investigated the relationship between Word List Memory Immediate Recall (WLM IR) and the Saving Score (SS) with having the APOE ε4 risk allele in the elderly with normal global cognitive assessment. Methods: A cross-sectional study on 105 subjects ≥60 years with normal MMSE scores who met inclusion criteria. Memory impairment (MI) if: WLM IR score on the third trial <8 or an SS score <80%. Results: The majority of the subjects were female (68.6%), 65 ± 7.1 years, had undertaken formal education for <6 years (56.2%), had MI (81%), and the APOE ε4 genotype was detected in 24.8% of subjects. There was a significant relationship between APOE ε4 and lower WLMIR (p = 0.02, OR 7.92, CI 95% (1.00–62.38)). Conclusions: WLM IR score is lower in elderly people with the APOE ε4 despite their normal global cognitive assessment results, and these scores were not influenced by education level. Further research needs to confirm that the WLM IR can be used to screen for early dementia.

HMGCR is a genetic modifier for risk, age of onset and MCI conversion to Alzheimer's disease in a three cohorts study

Several retrospective epidemiological studies report that utilization of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibitors called statins at mid-life can reduce the risk of developing sporadic Alzheimer's disease (AD) by as much as 70%. Conversely, the administration of these inhibitors in clinically diagnosed subjects with AD confers little or no benefits over time. Here, we investigated the association between AD and HMGCR rs3846662, a polymorphism known to be involved in the regulation of HMGCR exon 13 skipping, in a founder population and in two distinct mixed North American populations of converting mild cognitively impaired (MCI) subjects (Alzheimer's disease Cooperative study (ADCS) and Alzheimer's disease Neuroimaging Initiative (ADNI) cohorts). Targeting more specifically women, the G allele negative (G-) AD subjects exhibit delayed age of onset of AD (P=0.017) and significantly reduced risk of AD (OR: 0.521; P=0.0028), matching the effect size reported by the apolipoprotein E type 2 variant. Stratification for APOE4 in a large sample of MCI patients from the ADCS cohort revealed a significant protective effect of G negative carriers on AD conversion 3 years after MCI diagnosis (odds ratio (OR): 0.554; P=0.041). Conversion rate among APOE4 carriers with the HMGCR's G negative allele was markedly reduced (from 76% to 27%) to levels similar to APOE4 non-carriers (27.14%), which strongly indicate protection. Conversion data from the independent ADNI cohort also showed significantly reduced MCI or AD conversion among APOE4 carriers with the protective A allele (P=0.005). In conclusion, HMGCR rs3846662 acts as a potent genetic modifier for AD risk, age of onset and conversion.

Statins, cognition, and dementia—systematic review and methodological commentary

Firm conclusions about whether mid-life or long-term statin use has an impact on cognitive decline and dementia remain elusive. Here, our objective was to systematically review, synthesize and critique the epidemiological literature that examines the relationship between statin use and cognition, so as to assess the current state of knowledge, identify gaps in our understanding, and make recommendations for future research. We summarize the findings of randomized controlled trials (RCTs) and observational studies, grouped according to study design. We discuss the methods for each, and consider likely sources of bias, such as reverse causation and confounding. Although observational studies that considered statin use at or near the time of dementia diagnosis suggest a protective effect of statins, these findings could be attributable to reverse causation. RCTs and well-conducted observational studies of baseline statin use and subsequent cognition over several years of follow-up do not support a causal preventative effect of late-life statin use on cognitive decline or dementia. Given that much of the human research on statins and cognition in the future will be observational, careful study design and analysis will be essential.

Risk Profiles of Alzheimer Disease

Alzheimer disease (AD) is a dementing, neurodegenerative disorder that affects approximately 500,000 Canadians and its prevalence is expected to double over the next 30 years. Although several medications may temporarily augment cognitive abilities in AD, there presently exists no proven method to avoid the inevitable clinical deterioration in this devastating condition. The delineation of risk factors for the development of AD offers hope for the advent of effective prevention or interventions that might retard the onset of symptoms. In this article, we provide a comprehensive review of midlife risk factors implicated in the etiopathogenesis of sporadic AD. Although some risk factors are heritable and largely beyond our control, others are determined by lifestyle or environment and are potentially modifiable. In a companion paper, we introduce the concept of an Alzheimer Risk Assessment Clinic for ascertainment and mitigation of these and other putative dementia risk factors in middle-aged adults.

Cholesterol balance in prion diseases and Alzheimer's disease

Prion diseases are transmissible and fatal neurodegenerative disorders of humans and animals. They are characterized by the accumulation of PrP^Sc, an aberrantly folded isoform of the cellular prion protein PrP^C, in the brains of affected individuals. PrP^C is a cell surface glycoprotein attached to the outer leaflet of the plasma membrane by a glycosyl-phosphatidyl-inositol (GPI) anchor. Specifically, it is associated with lipid rafts, membrane microdomains enriched in cholesterol and sphinoglipids. It has been established that inhibition of endogenous cholesterol synthesis disturbs lipid raft association of PrP^C and prevents PrP^Sc accumulation in neuronal cells. Additionally, prion conversion is reduced upon interference with cellular cholesterol uptake, endosomal export, or complexation at the plasma membrane. Altogether, these results demonstrate on the one hand the importance of cholesterol for prion propagation. On the other hand, growing evidence suggests that prion infection modulates neuronal cholesterol metabolism. Similar results were reported in Alzheimer’s disease (AD): whereas amyloid β peptide formation is influenced by cellular cholesterol, levels of cholesterol in the brains of affected individuals increase during the clinical course of the disease. In this review, we summarize commonalities of alterations in cholesterol homeostasis and discuss consequences for neuronal function and therapy of prion diseases and AD.

Statins in oncological research: from experimental studies to clinical practice

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors are commonly used drugs in the treatment of dyslipidemias, primarily raised cholesterol. Recently, many epidemiological and preclinical studies pointed to anti-tumor properties of statins, including anti-proliferative activities, apoptosis, decreased angiogenesis and metastasis. These processes play an important role in carcinogenesis and, therefore, the role of statins in cancer disease is being seriously discussed among oncologists. Anti-neoplastic properties of statins combined with an acceptable toxicity profile in the majority of individuals support their further development as anti-tumor drugs. The mechanism of action, current preclinical studies and clinical efficacy of statins are reviewed in this paper. Moreover, promising results have been reported regarding the statins' efficacy in some cancer types, especially in esophageal and colorectal cancers, and hepatocellular carcinoma. Statins' hepatotoxicity has traditionally represented an obstacle to the prescription of this class of drugs and this issue is also discussed in this review.

Toward onset prevention of cognitive decline in adults with Down syndrome (the TOP-COG study): study protocol for a randomized controlled trial

BACKGROUND

Early-onset dementia is common in Down syndrome adults, who have trisomy 21. The amyloid precursor protein gene is on chromosome 21, and so is over-expressed in Down syndrome, leading to amyloid β (Aβ) over-production, a major upstream pathway leading to Alzheimer disease (AD). Statins (microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors), have pleiotropic effects including potentially increasing brain amyloid clearance, making them plausible agents to reduce AD risk. Animal models, human observational studies, and small scale trials support this rationale, however, there are no AD primary prevention trials in Down syndrome adults. In this study we study aim to inform the design of a full-scale primary prevention trial.

METHODS/DESIGN

TOP-COG is a feasibility and pilot double-blind randomized controlled trial (RCT), with a nested qualitative study, conducted in the general community. About 60 Down syndrome adults, aged ≥50 will be included. The intervention is oral simvastatin 40 mg at night for 12 months, versus placebo. The primary endpoint is recruitment and retention rates. Secondary endpoints are (1) tolerability and safety; (2) detection of the most sensitive neurocognitive instruments; (3) perceptions of Down syndrome adults and caregivers on whether to participate, and assessment experiences; (4) distributions of cognitive decline, adaptive behavior, general health/quality of life, service use, caregiver strain, and sample size implications; (5) whether Aβ42/Aβ40 is a cognitive decline biomarker. We will describe percentages recruited from each source, the number of contacts to achieve this, plus recruitment rate by general population size. We will calculate summary statistics with 90% confidence limits where appropriate, for each study outcome as a whole, by treatment group and in relation to baseline age, cognitive function, cholesterol and other characteristics. Changes over time will be summarized graphically. The sample size for a definitive RCT will be estimated under alternative assumptions.

DISCUSSION

This study is important, as AD is a major problem for Down syndrome adults, for whom there are currently no effective preventions or treatments. It will also delineate the most suitable assessment instruments for this population. Recruitment of intellectually disabled adults is notoriously difficult, and we shall provide valuable information on this, informing future studies.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN Register ID: ISRCTN67338640 (17 November 2011).

Possible modification of Alzheimer's disease by statins in midlife: interactions with genetic and non-genetic risk factors

The benefits of statins, commonly prescribed for hypercholesterolemia, in treating Alzheimer's disease (AD) have not yet been fully established. A recent randomized clinical trial did not show any therapeutic effects of two statins on cognitive function in AD. Interestingly, however, the results of the Rotterdam study, one of the largest prospective cohort studies, showed reduced risk of AD in statin users. Based on the current understanding of statin actions and AD pathogenesis, it is still worth exploring whether statins can prevent AD when administered decades before the onset of AD or from midlife. This review discusses the possible beneficial effects of statins, drawn from previous clinical observations, pathogenic mechanisms, which include β-amyloid (Aβ) and tau metabolism, genetic and non-genetic risk factors (apolipoprotein E, cholesterol, sex, hypertension, and diabetes), and other clinical features (vascular dysfunction and oxidative and inflammatory stress) of AD. These findings suggest that administration of statins in midlife might prevent AD in late life by modifying genetic and non-genetic risk factors for AD. It should be clarified whether statins inhibit Aβ accumulation, tau pathological features, and brain atrophy in humans. To answer this question, a randomized controlled study using amyloid positron emission tomography (PET), tau-PET, and magnetic resonance imaging would be useful. This clinical evaluation could help us to overcome this devastating disease.

Unintended effects of statins from observational studies in the general population: systematic review and meta-analysis

BACKGROUND

Efficacy of statins has been extensively studied, with much less information reported on their unintended effects. Evidence from randomized controlled trials (RCTs) on unintended effects is often insufficient to support hypotheses generated from observational studies. We aimed to systematically assess unintended effects of statins from observational studies in general populations with comparison of the findings where possible with those derived from randomized trials.

METHODS

Medline (1998 to January 2012, week 3) and Embase (1998 to 2012, week 6) were searched using the standard BMJ Cohort studies filter. The search was supplemented with reference lists of all identified studies and contact with experts in the field. We included prospective studies with a sample size larger than 1,000 participants, case control (of any size) and routine health service linkage studies of over at least one year duration. Studies in subgroups of patients or follow-up of patient case series were excluded, as well as hospital-based cohort studies.

RESULTS

Ninety studies were identified, reporting on 48 different unintended effects. Statins were associated with lower risks of dementia and cognitive impairment, venous thrombo-embolism, fractures and pneumonia, but these findings were attenuated in analyses restricted to higher quality studies (respectively: OR 0.74 (95% CI 0.62 to 0.87); OR 0.92 (95% CI 0.81 to 1.03); OR 0.97 (95% CI 0.88 to 1.05); OR 0.92 (95% CI 0.83 to 1.02)); and marked heterogeneity of effects across studies remained. Statin use was not related to any increased risk of depression, common eye diseases, renal disorders or arthritis. There was evidence of an increased risk of myopathy, raised liver enzymes and diabetes (respectively: OR 2.63 (95% CI 1.50 to 4.61); OR 1.54 (95% CI 1.47 to 1.62); OR 1.31 (95% CI 0.99 to 1.73)).

CONCLUSIONS

Our systematic review and meta-analyses indicate that high quality observational data can provide relevant evidence on unintended effects of statins to add to the evidence from RCTs. The absolute excess risk of the observed harmful unintended effects of statins is very small compared to the beneficial effects of statins on major cardiovascular events.

Statin use and incident dementia: a nationwide cohort study of Taiwan

BACKGROUND

Statins are widely used in clinical treatment. However, an U.S. Food and Drug Administration issued health alert has raised concerns for the adverse effects of statin-associated confusion and memory loss in the elderly people. It is necessary to clarify the relationship between statin use and risk of incident dementia as well as whether class effects exist.

METHODS

In this population-based retrospective cohort study, total 33,398 patients aged ≥ 60 years were selected from a subset of the Taiwan National Health Insurance Research Databases and followed up for tracking the occurrence of any type of dementia from 2000 to 2010. The Cox proportional hazards models were used.

RESULTS

Compared to nonusers, statin users had a significantly lower risk of incident dementia (hazard ratio [HR], 0.78; 95% CI, 0.72-0.85, p<0.001). The potency and the cumulative duration of statin utilized were associated with the reducing risk of dementia. After stratifying by gender, the risk of incident dementia was lower in female statin users (HR, 0.76; 95% CI, 0.68-0.85, p<0.001) than in male statin users (HR, 0.86; 95% CI, 0.75-0.98, p=0.024). Higher potency and longer cumulative duration of statin use were required for reducing the risk of incident dementia in male patients than in female patients.

CONCLUSION

Statin use was associated with a significantly lower risk of dementia in the elderly patients in Taiwan. The potency and the cumulative duration of statin utilized played critical roles.

Neuropsychiatric adverse events associated with statins: epidemiology, pathophysiology, prevention and management

Statins, or 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors, such as lovastatin, atorvastatin, simvastatin, pravastatin, fluvastatin, rosuvastatin and pitavastatin, are cholesterol-lowering drugs used in clinical practice to prevent coronary heart disease. These drugs are generally well tolerated and have been rarely associated with severe adverse effects (e.g. rhabdomyolysis). Over the years, case series and data from national registries of spontaneous adverse drug reaction reports have demonstrated the occurrence of neuropsychiatric reactions associated with statin treatment. They include behavioural alterations (severe irritability, homicidal impulses, threats to others, road rage, depression and violence, paranoia, alienation, antisocial behaviour); cognitive and memory impairments; sleep disturbance (frequent awakenings, shorter sleep duration, early morning awakenings, nightmares, sleepwalking, night terrors); and sexual dysfunction (impotence and decreased libido). Studies designed to investigate specific neuropsychiatric endpoints have yielded conflicting results. Several mechanisms, mainly related to inhibition of cholesterol biosynthesis, have been proposed to explain the detrimental effects of statins on the central nervous system. Approaches to prevent and manage such adverse effects may include drug discontinuation and introduction of dietary restrictions; maintenance of statin treatment for some weeks with close patient monitoring; switching to a different statin; dose reduction; use of ω-3 fatty acids or coenzyme Q10 supplements; and treatment with psychotropic drugs. The available information suggests that neuropsychiatric effects associated with statins are rare events that likely occur in sensitive patients. Additional data are required, and further clinical studies are needed.

The Cache County Study on Memory in Aging: factors affecting risk of Alzheimer's disease and its progression after onset

The Cache County Study on Memory in Aging is a longitudinal, population-based study of Alzheimer's disease (AD) and other dementias. Initiated in 1995 and extending to 2013, the study has followed over 5,000 elderly residents of Cache County, Utah (USA) for over twelve years. Achieving a 90% participation rate at enrolment, and spawning two ancillary projects, the study has contributed to the literature on genetic, psychosocial and environmental risk factors for AD, late-life cognitive decline, and the clinical progression of dementia after its onset. This paper describes the major study contributions to the literature on AD and dementia.

Statins and cognition: a systematic review and meta-analysis of short- and long-term cognitive effects

OBJECTIVE

To evaluate the effect of statins on short-term cognitive function and the long-term incidence of dementia.

PATIENTS AND METHODS

A systematic search was performed of MEDLINE, EMBASE, and the Cochrane Central Register from their inception to April 25, 2013. Adults with no history of cognitive dysfunction treated with statins were included from high-quality randomized controlled trials and prospective cohort studies after formal bias assessment.

RESULTS

Sixteen studies were included in qualitative synthesis and 11 in quantitative synthesis. Short-term trials did not show a consistent effect of statin therapy on cognitive end points. Digit Symbol Substitution Testing (a well-validated measure of cognitive function) was the most common short-term end point, with no significant differences in the mean change from baseline to follow-up between the statin and placebo groups (mean change, 1.65; 95% CI, -0.03 to 3.32; 296 total exposures in 3 trials). Long-term cognition studies included 23,443 patients with a mean exposure duration of 3 to 24.9 years. Three studies found no association between statin use and incident dementia, and 5 found a favorable effect. Pooled results revealed a 29% reduction in incident dementia in statin-treated patients (hazard ratio, 0.71; 95% CI, 0.61-0.82).

CONCLUSION

In patients without baseline cognitive dysfunction, short-term data are most compatible with no adverse effect of statins on cognition, and long-term data may support a beneficial role for statins in the prevention of dementia.

The association of anxiety and depression with future dementia diagnosis: a case-control study in primary care

BACKGROUND

Depression is identified as a risk factor for dementia. Little research has been carried out on the importance of anxiety, despite strong evidence of co-morbidity with depression.

OBJECTIVE

To examine the association of anxiety and depression with future dementia diagnosis.

METHODS

This case-control study was set in the Consultations in Primary Care Archive. Cases (n = 400), were patients aged >65 years old. About 1353 controls were matched to cases by gender, practice, age group and year of case diagnosis. Read codes of risk factors for dementia were searched in patient records. The associations of prior consultations for anxiety and depression, with future diagnosis of dementia were determined using multivariable logistic regression.

RESULTS

A past anxiety diagnosis was associated with a future dementia diagnosis [odds ratio 2.76 (95% confidence interval 2.11-3.62)]. The association of depression with dementia was attenuated by the high prevalence of anxiety within those who have depression. Including an interaction of depression and anxiety showed that having only depression was associated with future dementia diagnosis but a diagnosis of depression alongside anxiety did not increase the likelihood of a dementia diagnosis compared to having just an anxiety diagnosis.

CONCLUSION

Prior diagnosis of anxiety was strongly associated with dementia diagnosis after adjustment for other risk factors. The independent effect of depression was weaker compared to anxiety. Given the higher prevalence of anxiety primary care physicians should consider anxiety as well as depression as premorbid risk factors of dementia to improve early recognition and facilitate greater access to services.

The effects of statins on prevention of stroke and dementia: a review

Stroke is the third leading cause of death in the United States and places a heavy toll on health care spending, especially in the elderly population. The prevalence of stroke increases with increasing age. Over the last 2 decades, there have been substantial data supporting the use of statins in the primary, as well as secondary, prevention of stroke. Although most of these studies were designed to evaluate cerebrovascular accidents (CVA) only as secondary endpoints, the data show a significant reduction in strokes associated with statin use. There have been numerous studies that have demonstrated the relationship between serum cholesterol levels, specifically low-density lipoprotein cholesterol, on CVA and the beneficial effects of statins in this setting. Furthermore, in addition to the lipid-lowering properties of statins, these drugs have also been shown to possess cholesterol-independent pleotropic properties that have been associated with neuroprotection. Finally, the role of statins for the prevention of dementia is still highly debatable. We examine the role of this class of drugs in the setting of dementia, particularly from vascular causes and stroke.

Pharmacological Treatment of Mild Cognitive Impairment as a Prodromal Syndrome of Alzheimer´s Disease

Mild cognitive impairment (MCI) is a syndrome which, depending on various neurobiological, psychological and social factors, carries a high risk of developing into dementia. As far as diagnostic uncertainty and the heterogeneous underlying pathophysiological mechanisms are concerned, only limited therapeutic options are currently available. Clinical trials involving a wide range of substances have failed to show efficacy on primary and secondary outcome parameters. Most results reflect not only a lack of effectiveness of drug therapy but also methodological constraints in true prodromal Alzheimer´s disease (AD) based on clinical criteria. Biomarkers may help to identify MCI as a prodromal phase of dementia, so it is important to use them to improve specificity of case selection in future studies. For MCI as a prodromal syndrome of AD, clinical trials with disease modifying drugs that target underlying pathological mechanisms such as amyloid-beta accumulation and neurofibrillary tangle formation may help develop effective treatment options in the future. Alternative pharmacological approaches are currently being evaluated in ongoing phase 1 and phase 2 studies. Nevertheless, a lack of approved pharmacotherapeutic options has led to specific interventions that focus on patient education and life-style related factors receiving increasing attention.

Alzheimer's disease, cholesterol, and statins: the junctions of important metabolic pathways

Recent years have seen a significant increase in published data supporting the positive effects of statins on neurodegenerative diseases, in particular on Alzheimer's disease. Statins show neuroprotective activity by a combination of different cellular and systemic mechanisms that are based on the inhibition of the biosynthesis of cholesterol and isoprenoid by-products. The promising results obtained in vivo and in epidemiological studies are generally not in accordance with those of placebo-controlled randomized clinical trials. Nevertheless, these results make statins valuable assets for disease prevention rather than therapeutic agents for use when disease symptoms are already displayed. Thus, the modulation of midlife cholesterol and/or statin administration prior to the appearance of dementia or cognitive impairment may have a better long-term outcome.

Lowering the risk of Alzheimer's disease: evidence-based practices emerge from new research

BACKGROUND

The increasing prevalence of Alzheimer's disease (AD) and other aging-related dementias as the population ages will have a dramatic impact on both provision of health care and the economy if nothing is done to prevent or delay the onset of AD or to slow its progression.

METHODS

A comprehensive review of the literature in several promising areas of inquiry, other than those representing Food and Drug Administration (FDA)-approved AD- or dementia-specific pharmacologic therapies, that may impact the risk or progression of AD and related dementias was undertaken.

RESULTS

Results highlight a number of factors associated with AD and dementia. These include education and occupation, cognitive and leisure activities, exercise, cholesterol and statins, and head trauma.

CONCLUSIONS

Factors associated with AD and dementia may have potential as strategies useful in preventing or delaying AD and dementia or slowing its progression. Further research is needed to determine the validity and strength of the associations and to ascertain causality.