Statins and brain integrity in older adults: secondary analysis of the Health ABC study

Cerebrovascular Disease and Statins

Elevated low-density lipoprotein-cholesterol (LDL-C) is a causal factor for the development of atherosclerotic cardiovascular disease (ASCVD); accordingly, LDL-C lowering is associated with a decreased risk of progression of atherosclerotic plaques and development of complications. Currently, statins play a central role in any ASCVD management and prevention strategies, in relation to their lipid-lowering action and potentially to pleiotropic effects. After coronary artery disease, stroke is the most frequent cause of ASCVD mortality and the leading cause of acquired disability, a major public health problem. There is often a tendency to aggregate all types of stroke (atherothrombotic, cardioembolic, and haemorrhagic), which have, however, different causes and pathophysiology, what may lead to bias when interpreting the results of the studies. Survivors of a first atherothrombotic ischemic stroke are at high risk for coronary events, recurrent stroke, and vascular death. Although epidemiological studies show a weak relationship between cholesterol levels and cerebrovascular disease as a whole compared with other ASCVD types, statin intervention studies have demonstrated a decrease in the risk of stroke in patients with atherosclerosis of other territories and a decrease in all cardiovascular events in patients who have had a stroke. The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial demonstrated the benefit of high doses of atorvastatin in the secondary prevention of ischemic stroke. In this review, we discuss the evidence, use and recommendations of statins in the primary and secondary prevention of stroke, and their role in other scenarios such as the acute phase of ischemic stroke, cerebral hemorrhage, cardioembolic stroke, small vessel disease, and cognitive impairment.

Lipophilic vs. hydrophilic statins and psychiatric hospitalizations and emergency room visits in US Veterans with schizophrenia and bipolar disorder

Objective –

Psychiatric hospitalizations and emergency department (ED) visits are costly, stigmatizing, and often ineffective. Given the immune and kynurenine activation in bipolar disorder (BD) and schizophrenia, as well as the immune-modulatory effects of statins, we aimed to compare the relative risk (RRs) of psychiatric hospitalizations and ED visits between individuals prescribed lipophilic vs. hydrophilic statins vs. no statins. We hypothesized (a) reduced rates of hospitalization and ER utilization with statins versus no statins and (b) differences in outcomes between statins, as lipophilia increases the capability to penetrate the blood–brain barrier with potentially beneficial neuroimmune, antioxidant, neuroprotective, neurotrophic, and endothelial stabilizing effects, and, in contrast, potentially detrimental decreases in brain cholesterol concentrations leading to serotoninergic dysfunction, changes in membrane lipid composition, thus affecting ion channels and receptors.

Methods –

We used VA service utilization data from October 1, 2010 to September 30, 2015. The RRs for psychiatric hospitalization and ED visits, were estimated using robust Poisson regression analyses. The number of individuals analyzed was 683,129.

Results –

Individuals with schizophrenia and BD who received prescriptions for either lipophilic or hydrophilic statins had a lower RR of psychiatric hospitalization or ED visits relative to nonstatin controls. Hydrophilic statins were significantly associated with lower RRs of psychiatric hospitalization but not of ED visits, compared to lipophilic statins.

Conclusion –

The reduction in psychiatric hospitalizations in statin users (vs. nonusers) should be interpreted cautiously, as it carries a high risk of confounding by indication. While the lower RR of psychiatric hospitalizations in hydrophilic statins relative to the lipophilic statins is relatively bias free, the finding bears replication in a specifically designed study. If replicated, important clinical implications for personalizing statin treatment in patients with mental illness, investigating add-on statins for improved therapeutic control, and mechanistic exploration for identifying new treatment targets are natural next steps.

Update on Statin Treatment in Patients with Neuropsychiatric Disorders

Statins are widely accepted as first-choice agents for the prevention of lipid-related cardiovascular diseases. These drugs have both anti-inflammatory and anti-oxidant properties, which may also make them effective as potential treatment marked by perturbations in these pathways, such as some neuropsychiatric disorders. In this narrative review, we have investigated the effects of statin therapy in individuals suffering from major depressive disorder (MDD), schizophrenia, anxiety, obsessive-compulsive disorder (OCD), bipolar disorder (BD), delirium, and autism spectrum disorders using a broad online search of electronic databases. We also explored the adverse effects of these drugs to obtain insights into the benefits and risks associated with their use in the treatment of these disorders. Lipophilic statins (including simvastatin) because of better brain penetrance may have greater protective effects against MDD and schizophrenia. The significant positive effects of statins in the treatment of anxiety disorders without any serious adverse side effects were shown in numerous studies. In OCD, BD, and delirium, limitations, and contradictions in the available data make it difficult to draw conclusions on any positive effect of statins. The positive effects of simvastatin in autism disorders have been evaluated in only a small number of clinical trials. Although some studies showed positive effect of statins in some neuropsychiatric disorders, further prospective studies are needed to confirm this and define the most effective doses and treatment durations.

Effects of simvastatin on white matter integrity in healthy middle-aged adults

Background

The brain is the most cholesterol‐rich organ and myelin contains 70% of total brain cholesterol. Statins are potent cholesterol‐lowing medications used by millions of adults for prevention of vascular disease, yet the effect of statins on cholesterol‐rich brain white matter (WM) is largely unknown.

Methods

We used longitudinal neuroimaging data acquired from 73 healthy, cognitively unimpaired, statin‐naïve, middle‐aged adults during an 18‐month randomized controlled trial of simvastatin 40 mg daily (n = 35) or matching placebo (n = 38). ANCOVA models (covariates: age, sex, APOE‐ɛ4) tested the effect of treatment group on percent change in WM, gray matter (GM), and WM hyperintensity (WMH) neuroimaging measures at each study visit. Mediation analysis tested the indirect effects of simvastatin on WM microstructure through change in serum total cholesterol levels.

Results

At 18 months, the simvastatin group showed a significant preservation in global WM fractional anisotropy (β = 0.88%, 95% CI 0.27 to 1.50, P = 0.005), radial diffusivity (β = −1.10%, 95% CI −2.13 to −0.06, P = 0.039), and WM volume (β = 0.72%, 95% CI 0.13 to 1.32, P = 0.018) relative to the placebo group. There was no significant effect of simvastatin on GM or WMH volume. Change in serum total cholesterol mediated approximately 30% of the effect of simvastatin on WM microstructure.

Conclusions

Simvastatin treatment in healthy, middle‐aged adults resulted in preserved WM microstructure and volume at 18 months. The partial mediation by serum cholesterol reduction suggests both peripheral and central mechanisms. Future studies are needed to determine whether these effects persist and translate to cognitive outcomes.

Trial Registration

NCT00939822 (ClinicalTrials.gov).

The Cognitive Effects of Statins are Modified by Age

To reveal new insights into statin cognitive effects, we performed an observational study on a population-based sample of 245,731 control and 55,114 statin-taking individuals from the UK Biobank. Cognitive performance in terms of reaction time, working memory and fluid intelligence was analysed at baseline and two follow-ups (within 5-10 years). Subjects were classified depending on age (up to 65 and over 65 years) and treatment duration (1-4 years, 5-10 years and over 10 years). Data were adjusted for health- and cognition-related covariates. Subjects generally improved in test performance with repeated assessment and middle-aged persons performed better than older persons. The effect of statin use differed considerably between the two age groups, with a beneficial effect on reaction time in older persons and fluid intelligence in both age groups, and a negative effect on working memory in younger subjects. Our analysis suggests a modulatory impact of age on the cognitive side effects of statins, revealing a possible reason for profoundly inconsistent findings on statin-related cognitive effects in the literature. The study highlights the importance of characterising modifiers of statin effects to improve knowledge and shape guidelines for clinicians when prescribing statins and evaluating their side effects in patients.

The effect of atorvastatin on cognition and mood in bipolar disorder and unipolar depression patients: A secondary analysis of a randomized controlled trial

OBJECTIVES

Statins have recently been linked to having effects on cognition and mood in mood disorders, though results are mixed. In this paper, we use data from a recent randomized controlled trial (RCT) to examine the effect of statins on cognition and mood in patients with Bipolar Disorder (BD) and Major Depressive Disorder (MDD).

METHODS

This is a secondary analysis of a randomized, double-blind, placebo-controlled clinical trial (n = 60) originally designed to examine the effect of atorvastatin (n = 27) versus placebo (n = 33) for lithium-induced diabetes insipidus in BD and MDD patients who were using lithium. For this analysis, the primary outcome was global cognition Z-score at 12-weeks adjusted for baseline. The secondary cognition outcomes were (1) Screen for Cognitive Impairment in Psychiatry (SCIP), and (2) executive function Z-score. The primary mood outcome (secondary outcome of this analysis) was depression relapse during 12-week follow-up (Mongomery Asberg Depression Rating Scale (MADRS) ≥10). The secondary mood outcomes were (1) relapse rate into a manic episode, and (2) relapse rate into any mood episode.

RESULTS

After 12 weeks follow-up, atorvastatin and placebo groups did not differ in terms of global cognition Z-score (β = -0.009287 (-0.1698,0.1512), p-value = 0.91). Similarly, composite Z-scores for SCIP and executive functions did not differ significantly. Depression relapse during 12-week follow-up was not significantly different between the groups (χ² (1) = 0.148, p-value = 0.70). Similarly, there was no difference between groups regarding relapse into mania.

CONCLUSION

In BD and MDD patients with lithium-induced nephrogenic diabetes insipidus randomized to atorvastatin or placebo, we found no significant differences in cognition and mood outcomes at 12-week follow-up.

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 and cognition in late-life bipolar disorder

OBJECTIVES

Recent data suggests that statins have positive effects on cognition in older adults. Studies in patients with mood disorders have found contradicting positive and negative effects of statins on mood and cognition, with limited data in bipolar disorder (BD). The objective of this study was to assess the association between statin use and cognition in older adults with BD.

METHODS

In a cross-sectional sample of 143 euthymic older adults with BD (age ≥ 50), statin users (n = 48) and nonusers (n = 95) were compared for cognitive outcomes: Global and cognitive domain z-scores were calculated from detailed neuropsychological batteries using normative data from healthy comparators (n = 87).

RESULTS

The sample had a mean age of 64.3 (±8.9) years, 65.0% were female, with an average of 15.1 (±2.79) years of education. Statin users did not differ from nonusers on global (-0.60 [±0.69] vs -0.49 [±0.68], t[127] = 0.80, P = .42) or individual cognitive domains z-score.

CONCLUSIONS

In older patients with BD, statin use is not independently associated with cognitive impairment. This suggests that in older BD patients, the cognitive dysfunction associated with BD trumps the potential cognitive benefit that is associated with statins in older adults without a psychiatric disorder. Further, statins do not seem to exacerbate this cognitive dysfunction. Future longitudinal studies are needed to confirm these findings.

Statins and Brain Health: Alzheimer's Disease and Cerebrovascular Disease Biomarkers in Older Adults

BACKGROUND

Statins have been proposed to reduce the risk of Alzheimer's disease (AD).

OBJECTIVE

Assess whether long-term statin use was associated with neuroimaging biomarkers of aging and dementia.

METHODS

Methods: We analyzed neuroimaging biomarkers in 1,160 individuals aged 65+ from the Mayo Clinic Study of Aging, a population-based prospective longitudinal study of cognitive aging.

RESULTS

Statin-treated (5+ years of therapy) individuals had greater burden of mid-and late-life cardiovascular disease (p < 0.001) than statin-untreated (≤3 months) individuals. Lower fractional anisotropy in the genu of the corpus callosum, an early marker of cerebrovascular disease, was associated with long-term statin exposure (p < 0.035). No significant associations were identified between long-term statin exposure and cerebral amyloid or tau burden, AD pattern neurodegeneration, or white matter hyperintensity burden.

CONCLUSIONS

Long-term statin therapy was not associated with differences in AD biomarkers. Individuals with long-term statin exposure had worse white matter integrity in the genu of the corpus callosum, consistent with the coexistence of higher cerebrovascular risk factor burden in this group.

Longitudinal lipid profile variations and clinical change in Alzheimer's disease dementia

Hypercholesterolemia and statin use have been unevenly associated with clinical change in Alzheimer's disease dementia. In this longitudinal study, 192 consecutive outpatients with late-onset Alzheimer's disease dementia were stratified according to APOE haplotypes, and followed for one year to investigate associations of lipid profile variations and lipophilic statin therapy with changes in cognition, caregiver burden, basic and instrumental functionality. Overall, 102 patients (53.1%) carried APOE4+ haplotypes and 90 (46.9%) carried APOE4- haplotypes; 189 patients (98.4%) used either a cholinesterase inhibitor, or Memantine, or both; 144 patients had dyslipidemias and 143 of them received statin therapy. Total cholesterol, LDL-cholesterol, Mini-Mental State Examination scores, and functional independence scores were significantly lower at the end of the follow-up, while Clinical Dementia Rating sum-of-boxes scores were higher. Exclusively for APOE4- carriers, rising LDL-cholesterol levels were associated with a trend toward improvements in the Index of Independence in Activities of Daily Living (β=0.010; ρ=0.16), whereas rising HDL-cholesterol levels were associated with lowered scores (β=-0.051; ρ=0.04). Lipophilic statin therapy had non-significant protective effects over Clinical Dementia Rating sum-of-boxes score variations only for APOE4- carriers. APOE4- haplotypes might enhance lipid availability to protect neuronal membranes, thus overcoming their supposed dysfunction in cholesterol metabolism, while APOE4+ carriers have inefficient neural repair mechanisms. In conclusion, APOE haplotypes seem to influence the protective effects of lipid profile variations for patients with Alzheimer's disease dementia, but current evidence is insufficient to propose lipid-lowering drugs as specific anti-dementia therapy.

Serum low-density lipoprotein levels, statin use, and cognition in patients with coronary artery disease

AIM

Statins have been associated with decreased cognition due to the effects of low concentrations of low-density lipoprotein (LDL) on brain function. This has remained controversial and is particularly relevant to patients with coronary artery disease (CAD), who have an increased risk of cognitive decline and are frequently prescribed statins. This study hypothesized that low concentration of LDL is associated with poor cognition in CAD patients using statins. It also explored the association between high-dose versus low-dose statins on cognition in this population.

PATIENTS AND METHODS

Baseline cross-sectional data from a longitudinal study of 120 statin-using CAD patients were examined (mean statin duration 25±43 months). The main outcomes were measures of global cognition and cognitive domains, with poor cognition defined as cognitive performance ≤1 standard deviation below the population age and education adjusted means. A battery of cognitive tests was used to assess verbal memory, executive function, speed of processing, visuospatial memory, and global cognition. Adjusting for age, sex, education, and other covariates, multivariable logistic regression analyses assessed associations between low LDL levels (<1.5 mmol/L), statin use, and poor cognition.

RESULTS

LDL levels were not associated with global cognition or individual cognitive domains. High-dose statin use was associated with higher visuospatial memory (odds ratio, OR [95% confidence interval, CI] =0.12 [0.02-0.66], P=0.01) and executive functioning (OR =0.25 [0.06-0.99], P=0.05). This effect was independent of covariates such as LDL levels.

CONCLUSION

Low LDL levels do not appear to be associated with poor cognition in CAD patients using statins. Whether high-dose statin use may have positive effects on cognition in CAD patients could be investigated in future studies.