# The Effects of Statins on Cognitive Performance Are Mediated by Low-Density Lipoprotein, C-Reactive Protein, and Blood Glucose Concentrations

Mélissa Gentreau, Gull Rukh, Maud Miguet, Laura E Clemensson, Ahmed M Alsehli, Olga E Titova, Helgi B Schiöth

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Mélissa Gentreau, Gull Rukh, Maud Miguet, Laura E Clemensson, Ahmed M Alsehli, et al.. The Effects of Statins on Cognitive Performance Are Mediated by Low-Density Lipoprotein, C-Reactive Protein, and Blood Glucose Concentrations. Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 2023, 78 (11), pp.1964-1972. 10.1093/gerona/glad163. hal-04614027

HAL Id: hal-04614027

https://hal.science/hal-04614027

Submitted on 17 Jun 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>
<figure><img src="image_1.png" /></figure>

# The Effects of Statins on Cognitive Performance Are Mediated by Low-Density Lipoprotein, C-Reactive Protein, and Blood Glucose Concentrations

Mélissa Gentreau, PhD,<fnref n="1" />*, ID Gull Rukh, PhD,<fnref n="1" /> Maud Miguet, PhD<fnref n="1" /> Laura E. Clemensson, PhD,<fnref n="1" /> Ahmed M. Alsehli, PhD,<fnref n="2" /> Olga E. Titova, PhD,<fnref n="3" /> and Helgi B. Schiöth, PhD<fnref n="1" />

## Abstract

Statins are widely used for cardiovascular disease prevention but their effects on cognition remain unclear. Statins reduce cholesterol concentration and have been suggested to provide both beneficial and detrimental effects. Our aim was to investigate the cross-sectional and longitudinal association between statin use and cognitive performance, and whether blood low-density lipoprotein, high-density lipoprotein, triglycerides, glucose, C-reactive protein, and vitamin D biomarkers mediated this association. We used participants from the UK biobank aged 40–69 without neurological and psychiatric disorders (n = 147 502 and n = 24 355, respectively). We performed linear regression to evaluate the association between statin use and cognitive performance and, mediation analysis to quantify the total, direct, indirect effects and the proportion meditated by blood biomarkers. Statin use was associated with lower cognitive performance at baseline (β = −0.40 [−0.53, −0.28], p = <.0001), and this association was mediated by low-density lipoprotein (proportion mediated = 51.4%, p = .002), C-reactive protein (proportion mediated = −11%, p = .006) and blood glucose (proportion mediated = 2.6%, p = .018) concentrations. However, statin use was not associated with cognitive performance, measured 8 years later (β = −0.003 [−0.11, 0.10], p = .96). Our findings suggest that statins are associated with lower short-term cognitive performance by lowering low-density lipoprotein and raising blood glucose concentrations, and better performance by lowering C-reactive protein concentrations. In contrast, statins have no effect on long-term cognition and remain beneficial in reducing cardiovascular risk factors.

**Keywords:** Biomarkers, Cholesterol, Cognition, Hydroxymethylglutaryl CoA reductase inhibitors, Inflammation

Statins are among the most widely prescribed medications for primary and secondary prevention of cardiovascular diseases (1). They are 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) inhibitors that lead to reduced blood cholesterol concentration (2). High blood cholesterol at midlife has been associated with cognitive decline that may lead to the development of Alzheimer's disease (AD) and dementia (3,4). Thus, the period, where cognitive dysfunction is manifesting but dementia diagnosis is not established, may offer a potential therapeutic window for interventions based on repurposing of statins (5). Besides, statins might have effects beyond lipid lowering such as anti-inflammatory and anti-oxidant effects that may prevent cognitive dysfunction (6). However, the FDA has reported short-term cognitive dysfunction in the form of memory loss and confusion, now listed as possible adverse effects, raising the question of the beneficial effect of statins in preventing cognitive dysfunction (7).

Indeed, randomized controlled trials (RCTs) and observational studies have reported conflicting results that can

be explained by short follow-ups, low sample sizes, various designs, or reverse causation (8). For example, the Sydney Memory and Ageing and the Alzheimer's Disease Neuroimaging Initiative (ADNI) studies did not show a significant association between statin use and cognitive decline (9,10) but another study found that statin use was associated with slower cognitive decline over 10-year follow-up (11). Hence, the effects of statins on cognition are still debated and need to be replicated.

In addition, the cognitive effects of statins may differ depending on statin- and individual-related factors such as statin lipophilicity, sex, ethnicity, comorbidity, and genetic factors (12). For instance, lipophilic statins may have a greater effect on cognition as they easily cross the blood-brain barrier (13), and a recent meta-analysis shows that hydrophilic statins lowered the risk of dementia more strongly than lipophilic statins (14). Regarding, individual-related factors, a recent study showed that sex and ethnicity modify the association between statins and AD risk: high statin exposure was

<footnote n="1">¹Functional Pharmacology and Neuroscience, Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden.</footnote>

<footnote n="2">²Department of Physiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.</footnote>

<footnote n="3">³Medical Epidemiology, Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden.</footnote>

<footnote>*Address correspondence to: Mélissa Gentreau, PhD. E-mail: melissa.gentreau@uu.se</footnote>

<footnote>Decision Editor: Gustavo Duque, MD, PhD, FRACP, FGSA (Biological Sciences Section)</footnote>
<figure><img src="image_3.png" /></figure>

# The Effects of Statins on Cognitive Performance Are Mediated by Low-Density Lipoprotein, C-Reactive Protein, and Blood Glucose Concentrations

Mélissa Gentreau, PhD,<fnref n="1" />,*, ID Gull Rukh, PhD,<fnref n="1" /> Maud Miguet, PhD<fnref n="1" /> Laura E. Clemensson, PhD,<fnref n="1" /> Ahmed M. Alsehli, PhD,<fnref n="2" /> Olga E. Titova, PhD,<fnref n="3" /> and Helgi B. Schiöth, PhD<fnref n="1" />

## Abstract

Statins are widely used for cardiovascular disease prevention but their effects on cognition remain unclear. Statins reduce cholesterol concentration and have been suggested to provide both beneficial and detrimental effects. Our aim was to investigate the cross-sectional and longitudinal association between statin use and cognitive performance, and whether blood low-density lipoprotein, high-density lipoprotein, triglycerides, glucose, C-reactive protein, and vitamin D biomarkers mediated this association. We used participants from the UK biobank aged 40–69 without neurological and psychiatric disorders (n = 147 502 and n = 24 355, respectively). We performed linear regression to evaluate the association between statin use and cognitive performance and, mediation analysis to quantify the total, direct, indirect effects and the proportion meditated by blood biomarkers. Statin use was associated with lower cognitive performance at baseline (β = −0.40 [−0.53, −0.28], p = <.0001), and this association was mediated by low-density lipoprotein (proportion mediated = 51.4%, p = .002), C-reactive protein (proportion mediated = −11%, p = .006) and blood glucose (proportion mediated = 2.6%, p = .018) concentrations. However, statin use was not associated with cognitive performance, measured 8 years later (β = −0.003 [−0.11, 0.10], p = .96). Our findings suggest that statins are associated with lower short-term cognitive performance by lowering low-density lipoprotein and raising blood glucose concentrations, and better performance by lowering C-reactive protein concentrations. In contrast, statins have no effect on long-term cognition and remain beneficial in reducing cardiovascular risk factors.

**Keywords:** Biomarkers, Cholesterol, Cognition, Hydroxymethylglutaryl CoA reductase inhibitors, Inflammation

Statins are among the most widely prescribed medications for primary and secondary prevention of cardiovascular diseases (1). They are 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) inhibitors that lead to reduced blood cholesterol concentration (2). High blood cholesterol at midlife has been associated with cognitive decline that may lead to the development of Alzheimer's disease (AD) and dementia (3,4). Thus, the period, where cognitive dysfunction is manifesting but dementia diagnosis is not established, may offer a potential therapeutic window for interventions based on repurposing of statins (5). Besides, statins might have effects beyond lipid lowering such as anti-inflammatory and anti-oxidant effects that may prevent cognitive dysfunction (6). However, the FDA has reported short-term cognitive dysfunction in the form of memory loss and confusion, now listed as possible adverse effects, raising the question of the beneficial effect of statins in preventing cognitive dysfunction (7).

Indeed, randomized controlled trials (RCTs) and observational studies have reported conflicting results that can

be explained by short follow-ups, low sample sizes, various designs, or reverse causation (8). For example, the Sydney Memory and Ageing and the Alzheimer's Disease Neuroimaging Initiative (ADNI) studies did not show a significant association between statin use and cognitive decline (9,10) but another study found that statin use was associated with slower cognitive decline over 10-year follow-up (11). Hence, the effects of statins on cognition are still debated and need to be replicated.

In addition, the cognitive effects of statins may differ depending on statin- and individual-related factors such as statin lipophilicity, sex, ethnicity, comorbidity, and genetic factors (12). For instance, lipophilic statins may have a greater effect on cognition as they easily cross the blood-brain barrier (13), and a recent meta-analysis shows that hydrophilic statins lowered the risk of dementia more strongly than lipophilic statins (14). Regarding, individual-related factors, a recent study showed that sex and ethnicity modify the association between statins and AD risk: high statin exposure was

<footnote n="1">¹Functional Pharmacology and Neuroscience, Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden.</footnote>

<footnote n="2">²Department of Physiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia.</footnote>

<footnote n="3">³Medical Epidemiology, Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden.</footnote>

<footnote>*Address correspondence to: Mélissa Gentreau, PhD. E-mail: melissa.gentreau@uu.se</footnote>

<footnote>Decision Editor: Gustavo Duque, MD, PhD, FRACP, FGSA (Biological Sciences Section)</footnote>
associated with lower AD risk for everyone except Black men (15). Lower cognitive decline was also demonstrated in statin users with a history of coronary heart disease (CHD) compared with nonusers (9), and statins may be more effective in apolipoprotein ε4 allele (APOE4) carriers, as this is the major genetic risk factor for AD and is associated with higher cholesterol concentration (11).

Finally, statins may exert both negative and positive effects that could explain the disparity between studies. Indeed, previous research has demonstrated that statins can affect β-cell function and insulin sensitivity (16), and epidemiological studies have shown that statin use was associated with increased fasting blood glucose and diabetes progression (17,18). Independently of statin use, poor glycemic control, and diabetes are well-established risk factors for cognitive decline and AD (19). Therefore, statins might contribute to cognitive dysfunction through blood glucose dysregulation.

Nevertheless, statins also demonstrated anti-inflammatory effects. Clinical trials have consistently shown that statins lower C-reactive protein (CRP) concentrations, a marker of inflammation, by 15%–30%, independently of their effect on cholesterol (20). Moreover, inflammation has been linked to cognitive decline (21) suggesting that the anti-inflammatory properties of statins could be beneficial for cognitive function.

Another interesting aspect of statin use is its potential anti-oxidant effects. Some studies have suggested that statins, particularly simvastatin, and atorvastatin, may increase blood vitamin D concentrations. These statins are metabolized by the same cytochrome P450 enzyme (CYP3A4) as vitamin D (22), which could explain this interaction. Besides, higher vitamin D concentrations have been associated with better cognitive function (23). Therefore, statin could contribute to protecting cognition through these anti-oxidant effects.

Yet, no study has investigated whether diabetogenic, anti-inflammatory, and/or anti-oxidant effects mediated the relationship between statin use and cognition. Therefore, we ascertained whether statin use is associated with cognitive performance in short- and long-term. Then, because the primary effect of statin is to reduce blood cholesterol concentration, we first investigated whether the association between statin use and cognitive performance is mediated by low-density lipoprotein (LDL) and high-density lipoprotein (HDL) concentrations. Second, we asked whether this association is also mediated by diabetogenic, anti-inflammatory, and/or anti-oxidant effects using triglycerides, glucose, CRP, and vitamin D blood biomarkers.

# Method

## Study Population

The UK Biobank is a prospective cohort study of approximately 500 000 participants aged 40–69 from England, Scotland, and Wales recruited between 2006 and 2010. A description of the study has been provided elsewhere (24) and detailed information is available on the UK Biobank website (www.ukbiobank.ac.uk). Baseline data collection included sociodemographic and lifestyle information, medical history, medication use, physical measurements, and biological samples. The first repeat assessment (2012–2013) included ~20 000 participants who lived near an assessment center. The second repeat assessment (2014+) is still ongoing. The North West Multi-Centre Research Ethics Committee approved the UK Biobank study protocol and the Regional

Ethics Committee of Uppsala (Sweden) further approved the data use. All participants provided written informed consent. We used data released in January 2019. The present study excluded participants who withdrew their consent (n = 202), did not give medication information at baseline (n = 865), used both statins and other lipid-lowering medications (n = 6133), had prevalent neurological (n = 26 023) or psychiatric disorders (n = 4661) at baseline, and had missing values or ambiguous APOE genotypes (n = 13 357). The cross-sectional and longitudinal analyses included participants who had no missing data for the global cognition Z-score at baseline (n = 147 502) and at the second repeat assessment (n = 24 355), respectively (Figure 1).

## Statin Use

Information regarding regular cholesterol-lowering medications use was collected through a touchscreen questionnaire at baseline, verified during verbal interview, and reported as medication codes. Medication codes corresponding to statins were identified (Supplementary Appendix A) and summarized in a single variable (statin use: yes/no). A similar procedure was performed for collecting information regarding use of non-statin cholesterol-lowering medications (Supplementary Appendix B).

## Blood Samples

Nonfasting blood samples were collected at baseline. The protocol for the collection, processing, and archiving of blood samples has been previously described (25). LDL, HDL, triglycerides, and blood glucose concentrations were quantified using routine enzymatic methods. Serum CRP concentration was measured by immunoturbidimetry and the data were log-transformed for the analysis. Serum vitamin D concentration was quantified using a chemiluminescent immunoassay. Details about assay methods and quality control procedures are described elsewhere (26,27).

## Cognitive Tests

Participants completed 4 cognitive tests on the touch-screen questionnaire evaluating different cognitive domains

<figure><img src="image_2.png" /><figcaption>**Figure 1.** Flow chart of participants' selection at baseline (2006–2010) and the second repeat assessment (2014–2017).</figcaption></figure>
associated with lower AD risk for everyone except Black men (15). Lower cognitive decline was also demonstrated in statin users with a history of coronary heart disease (CHD) compared with nonusers (9), and statins may be more effective in apolipoprotein ε4 allele (APOE4) carriers, as this is the major genetic risk factor for AD and is associated with higher cholesterol concentration (11).

Finally, statins may exert both negative and positive effects that could explain the disparity between studies. Indeed, previous research has demonstrated that statins can affect β-cell function and insulin sensitivity (16), and epidemiological studies have shown that statin use was associated with increased fasting blood glucose and diabetes progression (17,18). Independently of statin use, poor glycemic control, and diabetes are well-established risk factors for cognitive decline and AD (19). Therefore, statins might contribute to cognitive dysfunction through blood glucose dysregulation.

Nevertheless, statins also demonstrated anti-inflammatory effects. Clinical trials have consistently shown that statins lower C-reactive protein (CRP) concentrations, a marker of inflammation, by 15%–30%, independently of their effect on cholesterol (20). Moreover, inflammation has been linked to cognitive decline (21) suggesting that the anti-inflammatory properties of statins could be beneficial for cognitive function.

Another interesting aspect of statin use is its potential anti-oxidant effects. Some studies have suggested that statins, particularly simvastatin, and atorvastatin, may increase blood vitamin D concentrations. These statins are metabolized by the same cytochrome P450 enzyme (CYP3A4) as vitamin D (22), which could explain this interaction. Besides, higher vitamin D concentrations have been associated with better cognitive function (23). Therefore, statin could contribute to protecting cognition through these anti-oxidant effects.

Yet, no study has investigated whether diabetogenic, anti-inflammatory, and/or anti-oxidant effects mediated the relationship between statin use and cognition. Therefore, we ascertained whether statin use is associated with cognitive performance in short- and long-term. Then, because the primary effect of statin is to reduce blood cholesterol concentration, we first investigated whether the association between statin use and cognitive performance is mediated by low-density lipoprotein (LDL) and high-density lipoprotein (HDL) concentrations. Second, we asked whether this association is also mediated by diabetogenic, anti-inflammatory, and/or anti-oxidant effects using triglycerides, glucose, CRP, and vitamin D blood biomarkers.

# Method

## Study Population

The UK Biobank is a prospective cohort study of approximately 500 000 participants aged 40–69 from England, Scotland, and Wales recruited between 2006 and 2010. A description of the study has been provided elsewhere (24) and detailed information is available on the UK Biobank website (www.ukbiobank.ac.uk). Baseline data collection included sociodemographic and lifestyle information, medical history, medication use, physical measurements, and biological samples. The first repeat assessment (2012–2013) included ~20 000 participants who lived near an assessment center. The second repeat assessment (2014+) is still ongoing. The North West Multi-Centre Research Ethics Committee approved the UK Biobank study protocol and the Regional

Ethics Committee of Uppsala (Sweden) further approved the data use. All participants provided written informed consent. We used data released in January 2019. The present study excluded participants who withdrew their consent (n = 202), did not give medication information at baseline (n = 865), used both statins and other lipid-lowering medications (n = 6133), had prevalent neurological (n = 26 023) or psychiatric disorders (n = 4661) at baseline, and had missing values or ambiguous APOE genotypes (n = 13 357). The cross-sectional and longitudinal analyses included participants who had no missing data for the global cognition Z-score at baseline (n = 147 502) and at the second repeat assessment (n = 24 355), respectively (Figure 1).

## Statin Use

Information regarding regular cholesterol-lowering medications use was collected through a touchscreen questionnaire at baseline, verified during verbal interview, and reported as medication codes. Medication codes corresponding to statins were identified (Supplementary Appendix A) and summarized in a single variable (statin use: yes/no). A similar procedure was performed for collecting information regarding use of non-statin cholesterol-lowering medications (Supplementary Appendix B).

## Blood Samples

Nonfasting blood samples were collected at baseline. The protocol for the collection, processing, and archiving of blood samples has been previously described (25). LDL, HDL, triglycerides, and blood glucose concentrations were quantified using routine enzymatic methods. Serum CRP concentration was measured by immunoturbidimetry and the data were log-transformed for the analysis. Serum vitamin D concentration was quantified using a chemiluminescent immunoassay. Details about assay methods and quality control procedures are described elsewhere (26,27).

## Cognitive Tests

Participants completed 4 cognitive tests on the touch-screen questionnaire evaluating different cognitive domains

<figure><img src="image_4.png" /><figcaption>Figure 1. Flow chart of participants' selection at baseline (2006–2010) and the second repeat assessment (2014–2017).</figcaption></figure>
(Supplementary Material): visuospatial memory (pairs matching test), reasoning (fluid intelligence test), processing speed (reaction time test), and prospective memory (prospective memory test). From these 4 cognitive test scores, we created a global cognitive Z-score as a proxy for global cognition. First, the 4 cognitive scores were re-coded such that higher positive values correspond to better cognitive performance. Then, we calculated Z-score for each cognitive domain by centering by the mean and reducing by the standard deviation. Finally, Z-scores were summed together to represent the global cognitive Z-score. The same procedure was applied to the cognitive scores of the second repeat assessment used for the longitudinal analysis.

## APOE Genotyping

Genotyping was performed using the Affymetrix UK Biobank and UK BiLEVE Axiom array (28,29). APOE genotypes were determined based on the 2 SNPs, rs429358 and rs7412 (Appendix C) as described elsewhere (30). Participants heterozygous for both SNPs resulted in ambiguous genotypes (ε2/ε4 or ε1/ε3) that did not clearly identify them as carriers of the ε4 allele. They were, therefore, excluded (31). APOE4 status was defined as carrying at least 1 ε4 allele.

## Covariates

At the baseline assessment, general information was collected on the touchscreen questionnaire. Ethnicity was recoded as white (British, Irish, or any other white background) versus non-white (ie, Mixed, Asian, or Asian British, Black or Black British, Chinese and another ethnic group) due to large majority of participants self-reporting as white (32). Education level was recoded from the education qualifications data as achieving college or university degree, as previously described (32,33). Townsend deprivation index (TDI) was used as a proxy of socioeconomic status of the participant based on the area of residence at baseline. Alcohol use and smoking status were defined as never, past, or current. Body mass index (BMI) was calculated from measured weight/height² (kg/m²). Physical activity was defined as number of days per week of moderate activity and was recoded into categories of low (0–1), medium (2–4), and high (5–7). History of diabetes, stroke, and CHD (angina and/or heart attack) were self-reported.

## Statistical Analysis

### Association between statin use and cognition

A linear regression model was used to evaluate the association between statin use at baseline and global cognition, either at baseline (cross-sectional analysis) or at the second repeat assessment (longitudinal analysis). The covariates considered as confounders, (selected using Direct Acyclic Graph method and based on literature data (34)) included assessment center, age, sex, education, APOE4 status, TDI, ethnicity, alcohol use, smoking, BMI, physical activity, a history of diabetes, stroke, CHD, and hypertension (Supplementary Figure 1). Interaction between statin and confounders were tested and kept in the final model when statistically significant (ie, statin × sex, statin × ethnicity, statin × diabetes, statin × hypertension, and statin × CHD). Indeed, participants with history of diabetes, stroke, CHD, or hypertension are more likely to be prescribed statins (1) and are at risk of cognitive dysfunction (35). We repeated this analysis for each cognitive test. Pairs matching score was modeled using

generalized linear model with a negative binomial distribution; fluid intelligence score and reaction time were modeled using linear model; prospective memory score was modeled using a logistic model, according to their respective distribution (Supplementary Figure 2).

Because of missing values for blood biomarkers (LDL, 5.5%; HDL 13.8%; triglycerides, 5.4%; blood glucose, 13.8%; CRP, 5.5%; vitamin, D 9.5%), the sample size varies across mediation analyses.

### Mediation analysis

We performed a mediation analysis based on the counterfactual outcome framework (36–38) to assess the mediation of blood biomarkers in the association between statin use and cognition. We considered each blood biomarker individually. The total effect of statin use on cognition was decomposed into direct and indirect effects by fitting two models: a mediator and an outcome model. The mediator model estimates the association between statin use and a blood biomarker (path α, Figure 2). The outcome model estimates the association between a blood biomarker and cognition, adjusted for statin use (path β, Figure 2). The average direct (θ₁), indirect (β₁θ₂), total effects (θ₁ + β₁θ₂), and their 95% confidence intervals were computed with the R *mediation* package (39) using 1000 simulations. The proportion mediated was calculated as (indirect effect/total effect) (38). We checked that there was no significant interaction between the exposure and the mediator (ie, statin use and blood biomarker) and considered as identifying assumptions for the interpretation of the average total effect, direct effect, indirect effect, and the proportion mediated, that there was no unmeasured confounding.

### Sensitivity analyses

Mediation analysis was repeated (a) excluding participants with a history of heart disease, stroke, diabetes, and hypertension to confirm that the mediation analysis results were not due to residual confounding bias; (b) restricting the analysis to simvastatin users versus nonusers, as most of statin users took simvastatin.

All statistical analyses were performed using R version 4.1.3 (The R Foundation for Statistical Computing, Vienna, Austria; www.R-project.org).

## Results

The sample of the cross-sectional analysis included 23220 statin users and 124282 nonusers. The participants' mean age was 56.59 (SD = 8.17) years and 45.68% were men (Table 1). Compared with nonusers, statin users were older and more likely to be men. They were less likely to have a college or university degree and more likely to carry APOE4. They tended to have a higher BMI and more often reported a history of diabetes, stroke, CHD, or hypertension. Most statin users took simvastatin (74.50%).

The sample of the longitudinal analysis included 2470 statin users and 21885 nonusers. The mean follow-up time between the baseline and the second repeat assessment was 8.0 (SD = 1.5) years. The participants' mean age was 54.68 (SD = 7.45) years, 48.80% were men. The characteristics between statin users and nonusers were comparable to the sample of the cross-sectional analysis (Supplementary Table 1).

Participants with missing data did not differ from the analytical sample.
(Supplementary Material): visuospatial memory (pairs matching test), reasoning (fluid intelligence test), processing speed (reaction time test), and prospective memory (prospective memory test). From these 4 cognitive test scores, we created a global cognitive Z-score as a proxy for global cognition. First, the 4 cognitive scores were re-coded such that higher positive values correspond to better cognitive performance. Then, we calculated Z-score for each cognitive domain by centering by the mean and reducing by the standard deviation. Finally, Z-scores were summed together to represent the global cognitive Z-score. The same procedure was applied to the cognitive scores of the second repeat assessment used for the longitudinal analysis.

## APOE Genotyping

Genotyping was performed using the Affymetrix UK Biobank and UK BiLEVE Axiom array (28,29). APOE genotypes were determined based on the 2 SNPs, rs429358 and rs7412 (Appendix C) as described elsewhere (30). Participants heterozygous for both SNPs resulted in ambiguous genotypes (ε2/ε4 or ε1/ε3) that did not clearly identify them as carriers of the ε4 allele. They were, therefore, excluded (31). APOE4 status was defined as carrying at least 1 ε4 allele.

## Covariates

At the baseline assessment, general information was collected on the touchscreen questionnaire. Ethnicity was recoded as white (British, Irish, or any other white background) versus non-white (ie, Mixed, Asian, or Asian British, Black or Black British, Chinese and another ethnic group) due to large majority of participants self-reporting as white (32). Education level was recoded from the education qualifications data as achieving college or university degree, as previously described (32,33). Townsend deprivation index (TDI) was used as a proxy of socioeconomic status of the participant based on the area of residence at baseline. Alcohol use and smoking status were defined as never, past, or current. Body mass index (BMI) was calculated from measured weight/height² (kg/m²). Physical activity was defined as number of days per week of moderate activity and was recoded into categories of low (0–1), medium (2–4), and high (5–7). History of diabetes, stroke, and CHD (angina and/or heart attack) were self-reported.

## Statistical Analysis

### Association between statin use and cognition

A linear regression model was used to evaluate the association between statin use at baseline and global cognition, either at baseline (cross-sectional analysis) or at the second repeat assessment (longitudinal analysis). The covariates considered as confounders, (selected using Direct Acyclic Graph method and based on literature data (34)) included assessment center, age, sex, education, APOE4 status, TDI, ethnicity, alcohol use, smoking, BMI, physical activity, a history of diabetes, stroke, CHD, and hypertension (Supplementary Figure 1). Interaction between statin and confounders were tested and kept in the final model when statistically significant (ie, statin × sex, statin × ethnicity, statin × diabetes, statin × hypertension, and statin × CHD). Indeed, participants with history of diabetes, stroke, CHD, or hypertension are more likely to be prescribed statins (1) and are at risk of cognitive dysfunction (35). We repeated this analysis for each cognitive test. Pairs matching score was modeled using

generalized linear model with a negative binomial distribution; fluid intelligence score and reaction time were modeled using linear model; prospective memory score was modeled using a logistic model, according to their respective distribution (Supplementary Figure 2).

Because of missing values for blood biomarkers (LDL, 5.5%; HDL 13.8%; triglycerides, 5.4%; blood glucose, 13.8%; CRP, 5.5%; vitamin, D 9.5%), the sample size varies across mediation analyses.

### Mediation analysis

We performed a mediation analysis based on the counterfactual outcome framework (36–38) to assess the mediation of blood biomarkers in the association between statin use and cognition. We considered each blood biomarker individually. The total effect of statin use on cognition was decomposed into direct and indirect effects by fitting two models: a mediator and an outcome model. The mediator model estimates the association between statin use and a blood biomarker (path α, Figure 2). The outcome model estimates the association between a blood biomarker and cognition, adjusted for statin use (path β, Figure 2). The average direct (θ₁), indirect (β₁θ₂), total effects (θ₁ + β₁θ₂), and their 95% confidence intervals were computed with the R *mediation* package (39) using 1000 simulations. The proportion mediated was calculated as (indirect effect/total effect) (38). We checked that there was no significant interaction between the exposure and the mediator (ie, statin use and blood biomarker) and considered as identifying assumptions for the interpretation of the average total effect, direct effect, indirect effect, and the proportion mediated, that there was no unmeasured confounding.

### Sensitivity analyses

Mediation analysis was repeated (a) excluding participants with a history of heart disease, stroke, diabetes, and hypertension to confirm that the mediation analysis results were not due to residual confounding bias; (b) restricting the analysis to simvastatin users versus nonusers, as most of statin users took simvastatin.

All statistical analyses were performed using R version 4.1.3 (The R Foundation for Statistical Computing, Vienna, Austria; www.R-project.org).

## Results

The sample of the cross-sectional analysis included 23220 statin users and 124282 nonusers. The participants' mean age was 56.59 (SD = 8.17) years and 45.68% were men (Table 1). Compared with nonusers, statin users were older and more likely to be men. They were less likely to have a college or university degree and more likely to carry APOE4. They tended to have a higher BMI and more often reported a history of diabetes, stroke, CHD, or hypertension. Most statin users took simvastatin (74.50%).

The sample of the longitudinal analysis included 2470 statin users and 21885 nonusers. The mean follow-up time between the baseline and the second repeat assessment was 8.0 (SD = 1.5) years. The participants' mean age was 54.68 (SD = 7.45) years, 48.80% were men. The characteristics between statin users and nonusers were comparable to the sample of the cross-sectional analysis (Supplementary Table 1).

Participants with missing data did not differ from the analytical sample.
<table><caption>**Table 1.** Characteristics of the Study Sample at Baseline</caption><thead><tr><th>Characteristics<br>Mean (SD) or n (%)</th><th>All Sample<br>n = 147502</th><th>Statin Nonusers<br>n = 124282</th><th>Statin Users<br>n = 23220</th></tr></thead><tbody><tr><td>Age</td><td>56.59 (8.20)</td><td>55.66 (8.20)</td><td>61.52 (6.04)</td></tr><tr><td>Sex (men)</td><td>67385 (45.68)</td><td>52907 (42.57)</td><td>14478 (62.35)</td></tr><tr><td>College or university degree</td><td>51284 (34.77)</td><td>44977 (36.19)</td><td>6307 (27.16)</td></tr><tr><td>TDI</td><td>-1.22 (2.89)</td><td>-1.26 (2.87)</td><td>-0.99 (3.02)</td></tr><tr><td>Ethnic background</td><td></td><td></td><td></td></tr><tr><td>White</td><td>136442 (92.50)</td><td>115093 (92.61)</td><td>21349 (91.94)</td></tr><tr><td>Mixed</td><td>1081 (0.73)</td><td>954 (0.77)</td><td>127 (0.55)</td></tr><tr><td>Asian or Asian British</td><td>3962 (2.69)</td><td>3069 (2.47)</td><td>893 (3.85)</td></tr><tr><td>Black and Black British</td><td>3356 (2.28)</td><td>2946 (2.37)</td><td>410 (1.77)</td></tr><tr><td>Chinese</td><td>538 (0.36)</td><td>473 (0.38)</td><td>65 (0.28)</td></tr><tr><td>Other ethnic group</td><td>1571 (1.07)</td><td>1303 (1.05)</td><td>268 (1.15)</td></tr><tr><td>APOE4 carriers</td><td>37608 (25.50)</td><td>30777 (24.76)</td><td>6831 (29.42)</td></tr><tr><td>Alcohol use</td><td></td><td></td><td></td></tr><tr><td>Never</td><td>6277 (4.26)</td><td>5115 (4.12)</td><td>1162 (5)</td></tr><tr><td>Previous</td><td>4961 (3.36)</td><td>3918 (3.15)</td><td>1043 (4.49)</td></tr><tr><td>Current</td><td>136135 (92.29)</td><td>115147 (92.65)</td><td>20988 (90.39)</td></tr><tr><td>Smoking status</td><td></td><td></td><td></td></tr><tr><td>Never</td><td>81496 (55.25)</td><td>70888 (57.04)</td><td>10608 (45.68)</td></tr><tr><td>Previous</td><td>51269 (34.76)</td><td>41099 (33.07)</td><td>10170 (43.80)</td></tr><tr><td>Current</td><td>14281 (9.68)</td><td>11942 (9.61)</td><td>2339 (10.07)</td></tr><tr><td>BMI (kg/m<sup>2</sup>)</td><td>27.28 (4.72)</td><td>26.94 (4.61)</td><td>29.15 (4.87)</td></tr><tr><td>Physical activity (days/week)</td><td></td><td></td><td></td></tr><tr><td>0-1</td><td>26916 (18.25)</td><td>22350 (17.98)</td><td>4566 (19.66)</td></tr><tr><td>2-4</td><td>56380 (38.22)</td><td>47725 (38.40)</td><td>8655 (37.27)</td></tr><tr><td>5-7</td><td>57656 (39.09)</td><td>49071 (39.48)</td><td>8585 (36.97)</td></tr><tr><td>Diabetes</td><td>6027 (4.09)</td><td>1736 (1.40)</td><td>4291 (18.48)</td></tr><tr><td>Stroke</td><td>1430 (0.97)</td><td>472 (0.38)</td><td>958 (4.13)</td></tr><tr><td>CHD</td><td>5670 (3.84)</td><td>1197 (0.96)</td><td>4473 (19.26)</td></tr><tr><td>Hypertension</td><td>37000 (25.08)</td><td>23235 (18.70)</td><td>13765 (59.28)</td></tr><tr><td>Type of statin</td><td></td><td></td><td></td></tr><tr><td>No statin</td><td>124282 (84.26)</td><td>-</td><td>-</td></tr><tr><td>Pravastatin</td><td>692 (0.47)</td><td>-</td><td>692 (2.98)</td></tr><tr><td>Rosuvastatin</td><td>742 (0.50)</td><td>-</td><td>742 (3.20)</td></tr><tr><td>Atorvastatin</td><td>4433 (3.01)</td><td>-</td><td>4433 (19.09)</td></tr><tr><td>Fluvastatin</td><td>53 (0.04)</td><td>-</td><td>53 (0.23)</td></tr><tr><td>Simvastatin</td><td>17300 (11.73)</td><td>-</td><td>17300 (74.50)</td></tr><tr><td>LDL (mmol/L)</td><td>3.56 (0.86)</td><td>3.71 (0.81)</td><td>2.77 (0.68)</td></tr><tr><td>HDL (mmol/L)</td><td>1.47 (0.39)</td><td>1.50 (0.39)</td><td>1.32 (0.35)</td></tr><tr><td>Triglycerides (mmol/L)</td><td>1.71 (0.99)</td><td>1.67 (0.98)</td><td>1.89 (1.05)</td></tr><tr><td>Blood glucose (mmol/L)</td><td>5.18 (1.11)</td><td>5.09 (0.87)</td><td>5.65 (1.86)</td></tr><tr><td>CRP (mg/L)</td><td>2.48 (4.17)</td><td>2.46 (4.14)</td><td>2.64 (4.37)</td></tr><tr><td>Vitamin D (nmol/L)</td><td>50.43 (21.28)</td><td>50.37 (21.18)</td><td>50.69 (21.77)</td></tr></tbody></table>

Notes: APOE4 = apolipoprotein E ε4; BMI = body mass index; CHD = coronary heart disease; CRP = C-reactive protein; SD = standard deviation; HDL = high-density lipoprotein; LDL = low-density lipoprotein; TDI = Townsend Deprivation Index.

## Cross-Sectional Association Between Statin Use and Cognitive Performance

First, we assessed the association between statin use and cognition at baseline without taking into account mediator paths. Statin use was significantly associated with lower global cognitive performance ($\beta$ = -.403 [-0.531, -0.276], *p* = <.0001) after adjustments for assessment center, age, sex, education, APOE4 status, TDI, ethnicity, alcohol use, smoking, BMI,

physical activity, history of diabetes, stroke, hypertension, CHD, and considering interactions between statin and sex, ethnicity, diabetes, hypertension, or CHD (Supplementary Table 2). The predicted values of the global cognition Z-score in the function of statin use and confounder interactions are presented in Supplementary Figure 3.

For the individual cognitive tests, we found similar results regarding fluid intelligence and reaction time tests
<table><caption>**Table 1.** Characteristics of the Study Sample at Baseline</caption><thead><tr><th>Characteristics<br>Mean (SD) or n (%)</th><th>All Sample<br>n = 147 502</th><th>Statin Nonusers<br>n = 124 282</th><th>Statin Users<br>n = 23 220</th></tr></thead><tbody><tr><td>Age</td><td>56.59 (8.20)</td><td>55.66 (8.20)</td><td>61.52 (6.04)</td></tr><tr><td>Sex (men)</td><td>67 385 (45.68)</td><td>52 907 (42.57)</td><td>14 478 (62.35)</td></tr><tr><td>College or university degree</td><td>51 284 (34.77)</td><td>44 977 (36.19)</td><td>6307 (27.16)</td></tr><tr><td>TDI</td><td>-1.22 (2.89)</td><td>-1.26 (2.87)</td><td>-0.99 (3.02)</td></tr><tr><td>Ethnic background</td><td></td><td></td><td></td></tr><tr><td>White</td><td>136 442 (92.50)</td><td>115 093 (92.61)</td><td>21 349 (91.94)</td></tr><tr><td>Mixed</td><td>1081 (0.73)</td><td>954 (0.77)</td><td>127 (0.55)</td></tr><tr><td>Asian or Asian British</td><td>3962 (2.69)</td><td>3069 (2.47)</td><td>893 (3.85)</td></tr><tr><td>Black and Black British</td><td>3356 (2.28)</td><td>2946 (2.37)</td><td>410 (1.77)</td></tr><tr><td>Chinese</td><td>538 (0.36)</td><td>473 (0.38)</td><td>65 (0.28)</td></tr><tr><td>Other ethnic group</td><td>1571 (1.07)</td><td>1303 (1.05)</td><td>268 (1.15)</td></tr><tr><td>APOE4 carriers</td><td>37 608 (25.50)</td><td>30 777 (24.76)</td><td>6831 (29.42)</td></tr><tr><td>Alcohol use</td><td></td><td></td><td></td></tr><tr><td>Never</td><td>6277 (4.26)</td><td>5115 (4.12)</td><td>1162 (5)</td></tr><tr><td>Previous</td><td>4961 (3.36)</td><td>3918 (3.15)</td><td>1043 (4.49)</td></tr><tr><td>Current</td><td>136 135 (92.29)</td><td>115 147 (92.65)</td><td>20 988 (90.39)</td></tr><tr><td>Smoking status</td><td></td><td></td><td></td></tr><tr><td>Never</td><td>81 496 (55.25)</td><td>70 888 (57.04)</td><td>10 608 (45.68)</td></tr><tr><td>Previous</td><td>51 269 (34.76)</td><td>41 099 (33.07)</td><td>10 170 (43.80)</td></tr><tr><td>Current</td><td>14 281 (9.68)</td><td>11 942 (9.61)</td><td>2339 (10.07)</td></tr><tr><td>BMI (kg/m²)</td><td>27.28 (4.72)</td><td>26.94 (4.61)</td><td>29.15 (4.87)</td></tr><tr><td>Physical activity (days/week)</td><td></td><td></td><td></td></tr><tr><td>0-1</td><td>26 916 (18.25)</td><td>22 350 (17.98)</td><td>4566 (19.66)</td></tr><tr><td>2-4</td><td>56 380 (38.22)</td><td>47 725 (38.40)</td><td>8655 (37.27)</td></tr><tr><td>5-7</td><td>57 656 (39.09)</td><td>49 071 (39.48)</td><td>8585 (36.97)</td></tr><tr><td>Diabetes</td><td>6027 (4.09)</td><td>1736 (1.40)</td><td>4291 (18.48)</td></tr><tr><td>Stroke</td><td>1430 (0.97)</td><td>472 (0.38)</td><td>958 (4.13)</td></tr><tr><td>CHD</td><td>5670 (3.84)</td><td>1197 (0.96)</td><td>4473 (19.26)</td></tr><tr><td>Hypertension</td><td>37 000 (25.08)</td><td>23 235 (18.70)</td><td>13 765 (59.28)</td></tr><tr><td>Type of statin</td><td></td><td></td><td></td></tr><tr><td>No statin</td><td>124 282 (84.26)</td><td>-</td><td>-</td></tr><tr><td>Pravastatin</td><td>692 (0.47)</td><td>692 (2.98)</td><td>692 (2.98)</td></tr><tr><td>Rosuvastatin</td><td>742 (0.50)</td><td>742 (3.20)</td><td>742 (3.20)</td></tr><tr><td>Atorvastatin</td><td>4433 (3.01)</td><td>4433 (19.09)</td><td>4433 (19.09)</td></tr><tr><td>Fluvastatin</td><td>53 (0.04)</td><td>53 (0.23)</td><td>53 (0.23)</td></tr><tr><td>Simvastatin</td><td>17 300 (11.73)</td><td>17 300 (74.50)</td><td>17 300 (74.50)</td></tr><tr><td>LDL (mmol/L)</td><td>3.56 (0.86)</td><td>3.71 (0.81)</td><td>2.77 (0.68)</td></tr><tr><td>HDL (mmol/L)</td><td>1.47 (0.39)</td><td>1.50 (0.39)</td><td>1.32 (0.35)</td></tr><tr><td>Triglycerides (mmol/L)</td><td>1.71 (0.99)</td><td>1.67 (0.98)</td><td>1.89 (1.05)</td></tr><tr><td>Blood glucose (mmol/L)</td><td>5.18 (1.11)</td><td>5.09 (0.87)</td><td>5.65 (1.86)</td></tr><tr><td>CRP (mg/L)</td><td>2.48 (4.17)</td><td>2.46 (4.14)</td><td>2.64 (4.37)</td></tr><tr><td>Vitamin D (nmol/L)</td><td>50.43 (21.28)</td><td>50.37 (21.18)</td><td>50.69 (21.77)</td></tr></tbody></table>

Notes: APOE4 = apolipoprotein E ε4; BMI = body mass index; CHD = coronary heart disease; CRP = C-reactive protein; SD = standard deviation; HDL = high-density lipoprotein; LDL = low-density lipoprotein; TDI = Townsend Deprivation Index.

## Cross-Sectional Association Between Statin Use and Cognitive Performance

First, we assessed the association between statin use and cognition at baseline without taking into account mediator paths. Statin use was significantly associated with lower global cognitive performance ($\beta$ = -.403 [-0.531, -0.276], $p$ = <.0001) after adjustments for assessment center, age, sex, education, APOE4 status, TDI, ethnicity, alcohol use, smoking, BMI,

physical activity, history of diabetes, stroke, hypertension, CHD, and considering interactions between statin and sex, ethnicity, diabetes, hypertension, or CHD (Supplementary Table 2). The predicted values of the global cognition Z-score in the function of statin use and confounder interactions are presented in Supplementary Figure 3.

For the individual cognitive tests, we found similar results regarding fluid intelligence and reaction time tests
<figure><img src="image_3.png" /><figcaption>**Figure 2.** Mediation analysis model of the associations between statin use and cognition, mediated by blood biomarkers independently (ie, LDL, HDL, triglycerides, blood glucose, CRP, and vitamin D). Path α represents the regression coefficient β₁ for the association between statin use and the blood biomarker. Path β represents the regression coefficient θ₂ for the association between the blood biomarker and the cognition. The indirect effect is represented by dotted arrows and the direct effect is by continuous arrow. The total effect is the sum of the direct and indirect effect.</figcaption></figure>

(Supplementary Table 2). Statin use was associated with the lower fluid intelligence score ($β = -0.231$ [-0.349, -0.114], $p = .0001$) and higher reaction time ($β = 12.993$ ms [8.457, 17.529], $p < .0001$). However, no significant association was found regarding pairs matching and prospective memory scores.

## Longitudinal Association Between Statin Use and Cognitive Performance

Second, we evaluated the association between statin use and cognition at the second repeat assessment. Statin use was not associated with global cognitive performance measured 8 years later after adjustments for confounders ($β = -0.003$ [-0.109, 0.104], $p = .96$) and, was not associated with any of the 4 cognitive scores (Supplementary Table 3).

## Mediation of Blood Biomarkers in the Association Between Statin Use and Cognitive Performance

Third, we investigated whether and how much LDL, HDL, triglycerides, blood glucose, CRP, and vitamin D concentrations mediated the association between statin use and cognitive performance (Figure 2). Because no association between statin use and cognition was found in the longitudinal analysis, the mediation analysis was performed regarding cognitive performance at baseline.

We assessed the association between statin use and each blood biomarker (path α, Figure 2), and each blood biomarker and global cognition at baseline (path β, Figure 2). The path α models showed that statin use was associated with lower LDL, HDL, and CRP concentrations and higher triglycerides, blood glucose and, vitamin D concentrations. Moreover, the path β models showed that higher LDL, HDL, and triglycerides and, lower CRP, blood glucose, and vitamin D concentrations were associated with increased global cognitive performance (Table 2).

Then, the average total, direct, indirect effects, and the proportion mediated were calculated (Table 3). The effect of statin on global cognitive performance (lower score) was mediated by decreased LDL (51.38%), HDL (4.35%), increased blood glucose (2.64%), and vitamin D (2.38%) concentrations. However, increased triglycerides concentration and decreased CRP concentration attenuated the effects of statins on global cognition with a negative mediated proportion of -0.53% and -11.02%, respectively.

## Sensitivity Analyses

When we excluded participants with the history of CHD, stroke, diabetes, and hypertension from the mediation

analysis, LDL, triglycerides, and CRP still significantly mediated the cognitive effect of statin but HDL, blood glucose, and vitamin D did not (Supplementary Table 4).

Finally, the mediation analysis was performed on simvastatin users versus nonusers. We found that the cognitive effect of simvastatin was mediated by decreased LDL (41.33%) and CRP (-8.60%), increased blood glucose (1.94%), and vitamin D (1.93%). However, no significant mediation by HDL and triglycerides concentrations were found (Supplementary Table 5).

## Discussion

We find statin use is associated with lower performance in global cognition, reasoning, and processing speed at baseline although this association is weakened in men, white ethnicity, and participants with history of diabetes, CHD, or hypertension. In addition, the effects of statins on global cognition were mediated by a decrease in LDL, CRP, and an increase in blood glucose concentrations. About 51.38% of the effects of statins were mediated by LDL and 2.64% by blood glucose concentrations. The proportion mediated by CRP was -11.02%. In contrast, we did not find a significant association between statin use and cognition measured 8 years later. Overall, our findings suggest that statins are associated with negative effects on short-term cognition through lowering LDL and elevating blood glucose, and positive effects through lowering CRP.

We found that statin use was significantly associated with short-term cognitive dysfunction but not with long-term cognition. Previous studies on the effects of statins on cognition have yielded contradictory results. Regarding short-term cognition, some studies reported adverse effects. In the ASPREE cohort, statin users had significantly lower performance in global cognition and episodic memory (40). In a RCT, patients also demonstrated lower cognitive performance after 6 months of simvastatin therapy (41). However, in a study of 7191 statin users and 17404 statin nonusers, statin was not significantly associated with cognitive impairment in the multivariate analysis (42). Regarding long-term cognition, there are mixed findings as recent observational studies with large sample sizes did not identify a significant association between statin use and cognitive decline (9,10,40), although some other studies found a protective association (11,43). These disparities between studies can be explained by different designs and adjustments. Indeed, the probability of statin use is conditioned by the presence of cardiovascular risk factors such as a history of hypertension, stroke, CHD, type 2 diabetes, or BMI, but these risk factors also affect cognition (1,35). Thus, by not adjusting for these factors, we might find an association between statin use and cognition that in fact, reflects the cardiovascular prevention by statins on cognition. We adjusted for cardiovascular risk factors and found significant protective interactions between statins and history of diabetes, CHD, and hypertension acknowledging the cardiovascular benefits that help prevent cognitive dysfunction. This protective effect was also found in older adults with type 2 diabetes (44), CHD, and hypertension (9). Therefore, although statins appear to exert short-term cognitive dysfunction, long-term statin use could outweigh these adverse effects by preventing cardiovascular diseases, which are important risk factors for cognitive decline and AD onset.

The mechanisms by which statins exert their cognitive effects are not fully elucidated. Here, we evaluated the
<figure><img src="image_5.png" /><figcaption>**Figure 2.** Mediation analysis model of the associations between statin use and cognition, mediated by blood biomarkers independently (ie, LDL, HDL, triglycerides, blood glucose, CRP, and vitamin D). Path α represents the regression coefficient β₁ for the association between statin use and the blood biomarker. Path β represents the regression coefficient θ₂ for the association between the blood biomarker and the cognition. The indirect effect is represented by dotted arrows and the direct effect is by continuous arrow. The total effect is the sum of the direct and indirect effect.</figcaption></figure>

(Supplementary Table 2). Statin use was associated with the lower fluid intelligence score ($β = -0.231$ [-0.349, -0.114], $p = .0001$) and higher reaction time ($β = 12.993$ ms [8.457, 17.529], $p < .0001$). However, no significant association was found regarding pairs matching and prospective memory scores.

## Longitudinal Association Between Statin Use and Cognitive Performance

Second, we evaluated the association between statin use and cognition at the second repeat assessment. Statin use was not associated with global cognitive performance measured 8 years later after adjustments for confounders ($β = -0.003$ [-0.109, 0.104], $p = .96$) and, was not associated with any of the 4 cognitive scores (Supplementary Table 3).

## Mediation of Blood Biomarkers in the Association Between Statin Use and Cognitive Performance

Third, we investigated whether and how much LDL, HDL, triglycerides, blood glucose, CRP, and vitamin D concentrations mediated the association between statin use and cognitive performance (Figure 2). Because no association between statin use and cognition was found in the longitudinal analysis, the mediation analysis was performed regarding cognitive performance at baseline.

We assessed the association between statin use and each blood biomarker (path α, Figure 2), and each blood biomarker and global cognition at baseline (path β, Figure 2). The path α models showed that statin use was associated with lower LDL, HDL, and CRP concentrations and higher triglycerides, blood glucose and, vitamin D concentrations. Moreover, the path β models showed that higher LDL, HDL, and triglycerides and, lower CRP, blood glucose, and vitamin D concentrations were associated with increased global cognitive performance (Table 2).

Then, the average total, direct, indirect effects, and the proportion mediated were calculated (Table 3). The effect of statin on global cognitive performance (lower score) was mediated by decreased LDL (51.38%), HDL (4.35%), increased blood glucose (2.64%), and vitamin D (2.38%) concentrations. However, increased triglycerides concentration and decreased CRP concentration attenuated the effects of statins on global cognition with a negative mediated proportion of -0.53% and -11.02%, respectively.

## Sensitivity Analyses

When we excluded participants with the history of CHD, stroke, diabetes, and hypertension from the mediation

analysis, LDL, triglycerides, and CRP still significantly mediated the cognitive effect of statin but HDL, blood glucose, and vitamin D did not (Supplementary Table 4).

Finally, the mediation analysis was performed on simvastatin users versus nonusers. We found that the cognitive effect of simvastatin was mediated by decreased LDL (41.33%) and CRP (-8.60%), increased blood glucose (1.94%), and vitamin D (1.93%). However, no significant mediation by HDL and triglycerides concentrations were found (Supplementary Table 5).

## Discussion

We find statin use is associated with lower performance in global cognition, reasoning, and processing speed at baseline although this association is weakened in men, white ethnicity, and participants with history of diabetes, CHD, or hypertension. In addition, the effects of statins on global cognition were mediated by a decrease in LDL, CRP, and an increase in blood glucose concentrations. About 51.38% of the effects of statins were mediated by LDL and 2.64% by blood glucose concentrations. The proportion mediated by CRP was -11.02%. In contrast, we did not find a significant association between statin use and cognition measured 8 years later. Overall, our findings suggest that statins are associated with negative effects on short-term cognition through lowering LDL and elevating blood glucose, and positive effects through lowering CRP.

We found that statin use was significantly associated with short-term cognitive dysfunction but not with long-term cognition. Previous studies on the effects of statins on cognition have yielded contradictory results. Regarding short-term cognition, some studies reported adverse effects. In the ASPREE cohort, statin users had significantly lower performance in global cognition and episodic memory (40). In a RCT, patients also demonstrated lower cognitive performance after 6 months of simvastatin therapy (41). However, in a study of 7191 statin users and 17404 statin nonusers, statin was not significantly associated with cognitive impairment in the multivariate analysis (42). Regarding long-term cognition, there are mixed findings as recent observational studies with large sample sizes did not identify a significant association between statin use and cognitive decline (9,10,40), although some other studies found a protective association (11,43). These disparities between studies can be explained by different designs and adjustments. Indeed, the probability of statin use is conditioned by the presence of cardiovascular risk factors such as a history of hypertension, stroke, CHD, type 2 diabetes, or BMI, but these risk factors also affect cognition (1,35). Thus, by not adjusting for these factors, we might find an association between statin use and cognition that in fact, reflects the cardiovascular prevention by statins on cognition. We adjusted for cardiovascular risk factors and found significant protective interactions between statins and history of diabetes, CHD, and hypertension acknowledging the cardiovascular benefits that help prevent cognitive dysfunction. This protective effect was also found in older adults with type 2 diabetes (44), CHD, and hypertension (9). Therefore, although statins appear to exert short-term cognitive dysfunction, long-term statin use could outweigh these adverse effects by preventing cardiovascular diseases, which are important risk factors for cognitive decline and AD onset.

The mechanisms by which statins exert their cognitive effects are not fully elucidated. Here, we evaluated the
<table><caption>**Table 2.** Association Between Statin Use, Blood Biomarkers and Global Cognitive Function</caption><thead><tr><th>Mediator</th><th>Path</th><th>β (CI)</th><th>p Value</th></tr></thead><tbody><tr><td>Statin → LDL</td><td>A</td><td>-0.642 (-0.690, -0.594)</td><td>&lt;.0001</td></tr><tr><td>LDL → cognition</td><td>B</td><td>0.043 (0.028, 0.059)</td><td>&lt;.0001</td></tr><tr><td>Statin → HDL</td><td>A</td><td>-0.083 (-0.105, -0.062)</td><td>&lt;.0001</td></tr><tr><td>HDL → cognition</td><td>B</td><td>0.041 (0.004, 0.077)</td><td>.0301</td></tr><tr><td>Statin → triglycerides</td><td>A</td><td>0.092 (0.034, 0.15)</td><td>.002</td></tr><tr><td>Triglycerides → cognition</td><td>B</td><td>0.018 (0.006, 0.03)</td><td>.0038</td></tr><tr><td>Statin → blood glucose</td><td>A</td><td>0.086 (0.021, 0.152)</td><td>.0098</td></tr><tr><td>Blood glucose → cognition</td><td>B</td><td>-0.018 (-0.030, -0.006)</td><td>.0033</td></tr><tr><td>Statin → CRP</td><td>A</td><td>-0.029 (-0.045, -0.014)</td><td>.0004</td></tr><tr><td>CRP → cognition</td><td>B</td><td>-0.162 (-0.208, -0.116)</td><td>&lt;.0001</td></tr><tr><td>Statin → Vitamin D</td><td>A</td><td>1.972 (0.703, 3.241)</td><td>.0023</td></tr><tr><td>Vitamin D → cognition</td><td>B</td><td>-0.001 (-0.001, -2 × 10<sup>-4</sup>)</td><td>.007</td></tr></tbody></table>

*Notes*: Path α represents the regression coefficient for the association between statin use and the blood biomarker. Path β represents the regression coefficient for the association between the blood biomarker and cognition. CI = confidence interval; CRP = C-reactive protein; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

<table><caption>**Table 3.** The Mediation Effect of Blood Biomarkers on the Cross-Sectional Association Between Statin Use and Global Cognition.</caption><thead><tr><th>Mediator</th><th>n</th><th>Total Effect β (CI)</th><th>Direct Effect β (CI)</th><th>Indirect Effect β (CI)</th><th>Proportion Mediated</th><th>P value of the Mediated Effect</th></tr></thead><tbody><tr><td>LDL</td><td>130 707</td><td>-0.067 (-0.124, -0.007)</td><td>-0.032 (-0.076, 0.013)</td><td>-0.034 (-0.048, -0.021)</td><td>51.38%</td><td>.002</td></tr><tr><td>HDL</td><td>119 244</td><td>-0.061 (-0.112, -0.01)</td><td>-0.058 (-0.107, -0.010)</td><td>-0.003 (-0.005, -0.0003)</td><td>4.35%</td><td>.04</td></tr><tr><td>Triglycerides</td><td>130 886</td><td>-0.067 (-0.113, -0.015)</td><td>-0.067 (-0.113, -0.016)</td><td>4 × 10<sup>-4</sup> (2 × 10<sup>-5</sup>, 0.001)</td><td>-0.53%</td><td>.042</td></tr><tr><td>Blood glucose</td><td>119 136</td><td>-0.062 (-0.114, -0.011)</td><td>-0.060 (-0.111, -0.010)</td><td>-0.002 (-0.003, -3 × 10<sup>-4</sup>)</td><td>2.64%</td><td>.018</td></tr><tr><td>CRP</td><td>130 710</td><td>-0.065 (-0.114, -0.018)</td><td>-0.072 (-0.119, -0.028)</td><td>0.007 (0.005, 0.010)</td><td>-11.02%</td><td>.006</td></tr><tr><td>Vitamin D</td><td>125 147</td><td>-0.064 (-0.113, -0.015)</td><td>-0.063 (-0.110, -0.015)</td><td>-0.002 (-0.003, -4 × 10<sup>-4</sup>)</td><td>2.38%</td><td>.01</td></tr></tbody></table>

*Notes*: CI = confidence interval; CRP = C-reactive protein; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

mediating effects of diabetogenic, anti-inflammatory, and/or anti-oxidant blood biomarkers in the relationship between statin and cognition. On one hand, our results suggest that statins are associated with negative effects on cognition. We demonstrated that LDL mediated the association between statin use and cognition by 51.38%, suggesting that reduced LDL concentration may be detrimental to cognition. One explanation for this result might be that LDL and cognition have a U-shaped relationship. Indeed, it has been shown that individuals under 70 had reduced cognitive performance for both low and high LDL concentrations (45). Besides, cholesterol is an important component of brain function, involved in synaptic plasticity and transmission (46). Thus, a optimum level may be needed for good neuronal functioning. In addition, we found that blood glucose may also partially mediate the effects of statins on cognition, even when controlling for diabetes. Indeed, poor glycemic control and type 2 diabetes are known risk factors for cognitive decline and AD (19) and statin use has been associated with increased fasting blood glucose (17) and diabetes progression (18). Preclinical studies indicate that statins alter β-cell function by the inhibition of L-type calcium channels and decrease insulin sensitivity through reduced phosphorylation of the insulin receptor substrate-1 (IRS-1) (16). Thus, statins may contribute to cognitive dysfunction by drastically lowering LDL concentration and affecting glycemic control.

On the other hand, we show that statins are associated with positive effects on cognition through lowering CRP. It has been suggested that simvastatin inhibits CRP by decreasing mevalonate and geranylgeranyl pyrophosphate (GGPP), products of the cholesterol biosynthesis pathway (mevalonate pathway) (47). Statins have also been associated with the reduction of other inflammatory markers such as TNF-α, IL-6, IL-1, (48) and inflammation has been associated with cognitive decline (21). Thus, statin may exert anti-inflammatory effects that help protect cognition.

Finally, we found inconsistent results regarding the mediation by triglycerides, HDL, and vitamin D. First, the mediations by HDL and triglycerides were not robust as the mediated proportions were no longer significant in the analysis on simvastatin use, suggesting either divergence effects depending on statin type or chance findings. Besides, in our sample, statin users had higher triglyceride and lower HDL concentrations than nonusers although RCTs demonstrated opposite results (49). Second, high vitamin D status has been found to be protective for cognition (23) but we found the opposite effect. These results may be explained by the cross-sectional design of our study, which does not rule out reverse causality. However, several interventional studies reported that statins may increase vitamin D concentration (50–52). In addition, other studies suggest that vitamin D status strengthens the effects of statins and may
<table><caption>**Table 2.** Association Between Statin Use, Blood Biomarkers and Global Cognitive Function</caption><thead><tr><th>Mediator</th><th>Path</th><th>β (CI)</th><th>p Value</th></tr></thead><tbody><tr><td>Statin → LDL</td><td>A</td><td>-0.642 (-0.690, -0.594)</td><td>&lt;.0001</td></tr><tr><td>LDL → cognition</td><td>B</td><td>0.043 (0.028, 0.059)</td><td>&lt;.0001</td></tr><tr><td>Statin → HDL</td><td>A</td><td>-0.083 (-0.105, -0.062)</td><td>&lt;.0001</td></tr><tr><td>HDL → cognition</td><td>B</td><td>0.041 (0.004, 0.077)</td><td>.0301</td></tr><tr><td>Statin → triglycerides</td><td>A</td><td>0.092 (0.034, 0.15)</td><td>.002</td></tr><tr><td>Triglycerides → cognition</td><td>B</td><td>0.018 (0.006, 0.03)</td><td>.0038</td></tr><tr><td>Statin → blood glucose</td><td>A</td><td>0.086 (0.021, 0.152)</td><td>.0098</td></tr><tr><td>Blood glucose → cognition</td><td>B</td><td>-0.018 (-0.030, -0.006)</td><td>.0033</td></tr><tr><td>Statin → CRP</td><td>A</td><td>-0.029 (-0.045, -0.014)</td><td>.0004</td></tr><tr><td>CRP → cognition</td><td>B</td><td>-0.162 (-0.208, -0.116)</td><td>&lt;.0001</td></tr><tr><td>Statin → Vitamin D</td><td>A</td><td>1.972 (0.703, 3.241)</td><td>.0023</td></tr><tr><td>Vitamin D → cognition</td><td>B</td><td>-0.001 (-0.001, -2 × 10<sup>-4</sup>)</td><td>.007</td></tr></tbody></table>

Notes: Path α represents the regression coefficient for the association between statin use and the blood biomarker. Path β represents the regression coefficient for the association between the blood biomarker and cognition. CI = confidence interval; CRP = C-reactive protein; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

<table><caption>**Table 3.** The Mediation Effect of Blood Biomarkers on the Cross-Sectional Association Between Statin Use and Global Cognition.</caption><thead><tr><th>Mediator</th><th>n</th><th>Total Effect β (CI)</th><th>Direct Effect β (CI)</th><th>Indirect Effect β (CI)</th><th>Proportion Mediated</th><th>P value of the Mediated Effect</th></tr></thead><tbody><tr><td>LDL</td><td>130 707</td><td>-0.067 (-0.124, -0.007)</td><td>-0.032 (-0.076, 0.013)</td><td>-0.034 (-0.048, -0.021)</td><td>51.38%</td><td>.002</td></tr><tr><td>HDL</td><td>119 244</td><td>-0.061 (-0.112, -0.01)</td><td>-0.058 (-0.107, -0.010)</td><td>-0.003 (-0.005, -0.0003)</td><td>4.35%</td><td>.04</td></tr><tr><td>Triglycerides</td><td>130 886</td><td>-0.067 (-0.113, -0.015)</td><td>-0.067 (-0.113, -0.016)</td><td>4 × 10<sup>-4</sup> (2 × 10<sup>-5</sup>, 0.001)</td><td>-0.53%</td><td>.042</td></tr><tr><td>Blood glucose</td><td>119 136</td><td>-0.062 (-0.114, -0.011)</td><td>-0.060 (-0.111, -0.010)</td><td>-0.002 (-0.003, -3 × 10<sup>-4</sup>)</td><td>2.64%</td><td>.018</td></tr><tr><td>CRP</td><td>130 710</td><td>-0.065 (-0.114, -0.018)</td><td>-0.072 (-0.119, -0.028)</td><td>0.007 (0.005, 0.010)</td><td>-11.02%</td><td>.006</td></tr><tr><td>Vitamin D</td><td>125 147</td><td>-0.064 (-0.113, -0.015)</td><td>-0.063 (-0.110, -0.015)</td><td>-0.002 (-0.003, -4 × 10<sup>-4</sup>)</td><td>2.38%</td><td>.01</td></tr></tbody></table>

Notes: CI = confidence interval; CRP = C-reactive protein; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

mediating effects of diabetogenic, anti-inflammatory, and/or anti-oxidant blood biomarkers in the relationship between statin and cognition. On one hand, our results suggest that statins are associated with negative effects on cognition. We demonstrated that LDL mediated the association between statin use and cognition by 51.38%, suggesting that reduced LDL concentration may be detrimental to cognition. One explanation for this result might be that LDL and cognition have a U-shaped relationship. Indeed, it has been shown that individuals under 70 had reduced cognitive performance for both low and high LDL concentrations (45). Besides, cholesterol is an important component of brain function, involved in synaptic plasticity and transmission (46). Thus, a optimum level may be needed for good neuronal functioning. In addition, we found that blood glucose may also partially mediate the effects of statins on cognition, even when controlling for diabetes. Indeed, poor glycemic control and type 2 diabetes are known risk factors for cognitive decline and AD (19) and statin use has been associated with increased fasting blood glucose (17) and diabetes progression (18). Preclinical studies indicate that statins alter β-cell function by the inhibition of L-type calcium channels and decrease insulin sensitivity through reduced phosphorylation of the insulin receptor substrate-1 (IRS-1) (16). Thus, statins may contribute to cognitive dysfunction by drastically lowering LDL concentration and affecting glycemic control.

On the other hand, we show that statins are associated with positive effects on cognition through lowering CRP. It has been suggested that simvastatin inhibits CRP by decreasing mevalonate and geranylgeranyl pyrophosphate (GGPP), products of the cholesterol biosynthesis pathway (mevalonate pathway) (47). Statins have also been associated with the reduction of other inflammatory markers such as TNF-α, IL-6, IL-1, (48) and inflammation has been associated with cognitive decline (21). Thus, statin may exert anti-inflammatory effects that help protect cognition.

Finally, we found inconsistent results regarding the mediation by triglycerides, HDL, and vitamin D. First, the mediations by HDL and triglycerides were not robust as the mediated proportions were no longer significant in the analysis on simvastatin use, suggesting either divergence effects depending on statin type or chance findings. Besides, in our sample, statin users had higher triglyceride and lower HDL concentrations than nonusers although RCTs demonstrated opposite results (49). Second, high vitamin D status has been found to be protective for cognition (23) but we found the opposite effect. These results may be explained by the cross-sectional design of our study, which does not rule out reverse causality. However, several interventional studies reported that statins may increase vitamin D concentration (50–52). In addition, other studies suggest that vitamin D status strengthens the effects of statins and may
have a synergic action by potentiating the reduction of LDL and triglyceride concentrations (53,54). Thus, statins may promote or potentiate anti-oxidant effects through vitamin D concentration.

The major strengths of this study include the large num-
ber of participants to detect interaction effects and small
effect sizes, as well as the longitudinal design. However,
the follow-up period may not be long enough to detect an
association between statin use and long-term cognition.
This may also be due to a lack of statistical power given
the reduced sample size in the longitudinal analysis; or
selection bias, as the participants completing the cognitive
tests at the second repeat assessment were slightly younger,
more likely to have achieved college or university degree
and less likely to have a medical history; or simply because
participants usually score better the second time. In addi-
tion, cognitive dysfunction may result from different con-
ditions, not all of which will manifest in future dementia,
which may explain the difference in studies evaluating the
benefit of statins in AD onset (8). This study is the first to
quantify the mediation by blood biomarkers in the associa-
tion between statins and cognition. Besides, we adjusted for
multiple confounders. However, our study presents some
limitations. First, we could not adjust for the duration of
statin therapy, dosage, or the age at which dyslipidemia was
diagnosed because this information was not available in the
UK Biobank. Second, for most participants, blood samples
were not collected in the fasting state, which may alter esti-
mates, although earlier studies found no clinical difference
between nonfasting and fasting lipid concentrations (55).
Regarding blood glucose concentrations, we adjusted for
type 2 diabetes to attenuate this bias. Third, the mediation
analysis is based on a cross-sectional design. Hence, these
results should be interpreted with caution as they do not
establish causality. However, our study does allow us to
explore potential associations and generate hypotheses for
further investigation.

Conclusion

This study displays that statin use is associated with both
positive and negative effects on cognitive performance which
may explain why most longitudinal studies, including ours,
have not found a significant association between statins and
long-term cognition. This study provides an explanation for
the conflicting results of statin effects on cognition and a
foundation for further studies to understand the underlying
mechanisms. Statin use remains effective in preventing cardio-
vascular disease which is an important component of cogni-
tive decline and AD onset.

Supplementary Material

Supplementary data are available at *The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences* online.

Funding

This research has been conducted using the UK Biobank re-
source under UK Biobank data application number 30172.
H.B.S. is supported by the Swedish Research Council. M.G.
is supported by the Tore Nilsson Foundation and the Lars

Hiertas Minne Foundation. M.M. is supported by the Emil
and Ragna Börjesons Foundation. L.E.C. is supported by the
Tore Nilsson Foundation.

Conflict of Interest

None.

Data Availability

The data that support the findings of this study are available
from the UK Biobank data resources but restrictions apply
to the availability of these data, which were used under li-
cense for the current study, and so are not publicly available.
Data are however available from the authors upon reason-
able request and with permission of the UK Biobank data
resources.

Acknowledgments

We thank all participants of the UK Biobank for their gen-
erous contribution. We thank Liisa Byberg from Uppsala
University for useful comments on the analyses.

Author Contributions

Conceptualization: M.G., H.B.S.; methodology, M.G.; software, M.G.; validation, M.G.; formal analysis, M.G.; investigation, M.G.; resources, M.G., G.R., M.M., L.E.C.; data curation, G.R., L.E.C.; writing—original draft preparation, M.G.; writing—review and editing, M.G., G.R., M.M., A.M.A., O.E.T., H.B.S.; visualization, M.G.; supervision, H.B.S.; project administration, M.G.; funding acquisition, H.B.S.

Ethics Approval and Consent to Participate

The North West Multi-Centre Research Ethics Committee approved the UK Biobank study protocol and the Regional Ethics Committee of Uppsala (Sweden) further approved the data use. All participants provided written informed consent.

References

1. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/ AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. *J Am Coll Cardiol*. 2019;73(24):e285–e350. doi:10.1016/j.jacc.2018.11.003

2. Tobert JA. Lovastatin and beyond: the history of the HMG-CoA reductase inhibitors. *Nat Rev Drug Discov*. 2003;2(7):517–526. doi:10.1038/nrd1112

3. Anstey KJ, Lipnicki DM, Low LF. Cholesterol as a risk factor for dementia and cognitive decline: a systematic review of prospective studies with meta-analysis. *Am J Geriatr Psychiatry*. 2008;16(5):343–354. doi:10.1097/JGP.0b013e31816b72d4

4. Centreau M, Chuy V, Féart C, et al. Refined carbohydrate-rich diet is associated with long-term risk of dementia and Alzheimer's disease in apolipoprotein E ε4 allele carriers. *Alzheimers Dement*. 2020;16(7):1043–1053. doi:10.1002/alz.12114

5. Rask-Andersen M, Almén MS, Schiöth HB. Trends in the exploitation of novel drug targets. *Nat Rev Drug Discov*. 2011;10(8):579–590. doi:10.1038/nrd3478

6. McFarland AJ, Anoopkumar-Dukie S, Arora DS, et al. Molecular mechanisms underlying the effects of statins in the central nervous
have a synergic action by potentiating the reduction of LDL and triglyceride concentrations (53,54). Thus, statins may promote or potentiate anti-oxidant effects through vitamin D concentration.

The major strengths of this study include the large num-
ber of participants to detect interaction effects and small
effect sizes, as well as the longitudinal design. However,
the follow-up period may not be long enough to detect an
association between statin use and long-term cognition.
This may also be due to a lack of statistical power given
the reduced sample size in the longitudinal analysis; or
selection bias, as the participants completing the cognitive
tests at the second repeat assessment were slightly younger,
more likely to have achieved college or university degree
and less likely to have a medical history; or simply because
participants usually score better the second time. In addi-
tion, cognitive dysfunction may result from different con-
ditions, not all of which will manifest in future dementia,
which may explain the difference in studies evaluating the
benefit of statins in AD onset (8). This study is the first to
quantify the mediation by blood biomarkers in the associa-
tion between statins and cognition. Besides, we adjusted for
multiple confounders. However, our study presents some
limitations. First, we could not adjust for the duration of
statin therapy, dosage, or the age at which dyslipidemia was
diagnosed because this information was not available in the
UK Biobank. Second, for most participants, blood samples
were not collected in the fasting state, which may alter esti-
mates, although earlier studies found no clinical difference
between nonfasting and fasting lipid concentrations (55).
Regarding blood glucose concentrations, we adjusted for
type 2 diabetes to attenuate this bias. Third, the mediation
analysis is based on a cross-sectional design. Hence, these
results should be interpreted with caution as they do not
establish causality. However, our study does allow us to
explore potential associations and generate hypotheses for
further investigation.

Conclusion

This study displays that statin use is associated with both
positive and negative effects on cognitive performance which
may explain why most longitudinal studies, including ours,
have not found a significant association between statins and
long-term cognition. This study provides an explanation for
the conflicting results of statin effects on cognition and a
foundation for further studies to understand the underlying
mechanisms. Statin use remains effective in preventing cardio-
vascular disease which is an important component of cogni-
tive decline and AD onset.

Supplementary Material

Supplementary data are available at *The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences* online.

Funding

This research has been conducted using the UK Biobank re-
source under UK Biobank data application number 30172.
H.B.S. is supported by the Swedish Research Council. M.G.
is supported by the Tore Nilsson Foundation and the Lars

Hiertas Minne Foundation. M.M. is supported by the Emil
and Ragna Börjesons Foundation. L.E.C. is supported by the
Tore Nilsson Foundation.

Conflict of Interest

None.

Data Availability

The data that support the findings of this study are available
from the UK Biobank data resources but restrictions apply
to the availability of these data, which were used under li-
cense for the current study, and so are not publicly available.
Data are however available from the authors upon reason-
able request and with permission of the UK Biobank data
resources.

Acknowledgments

We thank all participants of the UK Biobank for their gen-
erous contribution. We thank Liisa Byberg from Uppsala
University for useful comments on the analyses.

Author Contributions

Conceptualization: M.G., H.B.S.; methodology, M.G.; software, M.G.; validation, M.G.; formal analysis, M.G.; investigation, M.G.; resources, M.G., G.R., M.M., L.E.C.; data curation, G.R., L.E.C.; writing—original draft preparation, M.G.; writing—review and editing, M.G., G.R., M.M., A.M.A., O.E.T., H.B.S.; visualization, M.G.; supervision, H.B.S.; project administration, M.G.; funding acquisition, H.B.S.

Ethics Approval and Consent to Participate

The North West Multi-Centre Research Ethics Committee approved the UK Biobank study protocol and the Regional Ethics Committee of Uppsala (Sweden) further approved the data use. All participants provided written informed consent.

References

1. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/ AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. *J Am Coll Cardiol*. 2019;73(24):e285–e350. doi:10.1016/j.jacc.2018.11.003

2. Tobert JA. Lovastatin and beyond: the history of the HMG-CoA reductase inhibitors. *Nat Rev Drug Discov*. 2003;2(7):517–526. doi:10.1038/nrd1112

3. Anstey KJ, Lipnicki DM, Low LF. Cholesterol as a risk factor for dementia and cognitive decline: a systematic review of prospective studies with meta-analysis. *Am J Geriatr Psychiatry*. 2008;16(5):343–354. doi:10.1097/JGP.0b013e31816b72d4

4. Centreau M, Chuy V, Féart C, et al. Refined carbohydrate-rich diet is associated with long-term risk of dementia and Alzheimer's disease in apolipoprotein E ε4 allele carriers. *Alzheimers Dement*. 2020;16(7):1043–1053. doi:10.1002/alz.12114

5. Rask-Andersen M, Almén MS, Schiöth HB. Trends in the exploita-
tion of novel drug targets. *Nat Rev Drug Discov*. 2011;10(8):579–
590. doi:10.1038/nrd3478

6. McFarland AJ, Anoopkumar-Dukie S, Arora DS, et al. Molecular mechanisms underlying the effects of statins in the central nervous
system. *Int J Mol Sci*. 2014;15(11):20607-20637. doi:10.3390/ijms151120607

7. U.S. Food and Drug Administration. *Cholesterol-lowering drugs get labeling changes*. 2015. Accessed September 1, 2022. https://www.fda.gov/drugs/special-features/cholesterol-lowering-drugs-get-labelling-changes

8. Power MC, Weuve J, Sharrett AR, Blacker D, Gottesman RF. Statins, cognition, and dementia—systematic review and methodological commentary. *Nat Rev Neurol*. 2015;11(4):220-229. doi:10.1038/nrneurol.2015.35

9. Samaras K, Makkar SR, Crawford JD, et al. Effects of statins on memory, cognition, and brain volume in the elderly. *J Am Coll Cardiol*. 2019;74(21):2554-2568. doi:10.1016/j.jacc.2019.09.041

10. Kemp EC, Ebner MK, Ramanan S, et al.; Alzheimer's Disease Neuroimaging Initiative. Statin use and risk of cognitive decline in the ADNI cohort. *Am J Geriatr Psychiatry*. 2020;28(5):507-517. doi:10.1016/j.jagp.2019.11.003

11. Geifman N, Brinton RD, Kennedy RE, Schneider LS, Butte AJ. Evidence for benefit of statins to modify cognitive decline and risk in Alzheimer's disease. *Alzheimers Res Ther*. 2017;9(1):10. doi:10.1186/s13195-017-0237-y

12. Jamshidnejad-Tosaramandani T, Kashanian S, Al-Sabri MH, et al. Statins and cognition: modifying factors and possible underlying mechanisms. *Front Aging Neurosci*. 2022;14:968039. doi:10.3389/fnagi.2022.968039

13. Sodero AO, Barrantes FJ. Pleiotropic effects of statins on brain cells. *Biochim Biophys Acta Biomembr*. 2020;1862(9):183340. doi:10.1016/j.bbamem.2020.183340

14. Poly TN, Islam MM, Walther BA, et al. Association between use of statin and risk of dementia: a meta-analysis of observational studies. *Neuroepidemiology*. 2020;54(3):214-226. doi:10.1159/000503105

15. Zissimopoulos JM, Barthold D, Brinton RD, Joyce G. Sex and race differences in the association between statin use and the incidence of Alzheimer disease. *JAMA Neurol*. 2017;74(2):225-232. doi:10.1001/jamaneurol.2016.3783

16. Betteridge DJ, Carmena R. The diabetogenic action of statins—mechanisms and clinical implications. *Nat Rev Endocrinol*. 2016;12(2):99-110. doi:10.1038/nrendo.2015.194

17. Kim J, Lee HS, Lee KY. Effect of statins on fasting glucose in non-diabetic individuals: nationwide population-based health examination in Korea. *Cardiovasc Diabetol*. 2018;17(1):155. doi:10.1186/s12933-018-0799-4

18. Mansi IA, Chansard M, Lingvay I, Zhang S, Halm EA, Alvarez CA. Association of statin therapy initiation with diabetes progression: a retrospective matched-cohort study. *JAMA Intern Med*. 2021;181(12):1562-1574. doi:10.1001/jamainternmed.2021.5714

19. Cukierman T, Gerstein HC, Williamson JD. Cognitive decline and dementia in diabetes—systematic overview of prospective observational studies. *Diabetologia*. 2005;48(12):2460-2469. doi:10.1007/s00125-005-0023-4

20. Jain MK, Ridker PM. Anti-inflammatory effects of statins: clinical evidence and basic mechanisms. *Nat Rev Drug Discov*. 2005;4(12):977-987. doi:10.1038/nrd1901

21. Walker KA, Gottesman RF, Wu A, et al. Systemic inflammation during midlife and cognitive change over 20 years: the ARIC Study. *Neurology*. 2019;92(11):e1256-e1267. doi:10.1212/WNL.0000000000007094

22. Mazidi M, Rezaie P, Vatanparast H, Kengne AP. Effect of statins on serum vitamin D concentrations: a systematic review and meta-analysis. *Eur J Clin Invest*. 2017;47(1):93-101. doi:10.1111/eci.12698

23. Goodwill AM, Szoeke C. A systematic review and meta-analysis of the effect of low vitamin D on cognition. *J Am Geriatr Soc*. 2017;65(10):2161-2168. doi:10.1111/jgs.15012

24. Sudlow C, Gallacher J, Allen N, et al. UK Biobank: an open access resource for identifying the causes of a wide range of complex diseases of middle and old age. *PLoS Med*. 2015;12(3):e1001779. doi:10.1371/journal.pmed.1001779

25. Elliott P, Peakman TC, Biobank UK. The UK Biobank sample handling and storage protocol for the collection, processing, and archiving of human blood and urine. *Int J Epidemiol*. 2008;37(2):234-244. doi:10.1093/ije/dym276

26. UK Biobank. *Companion document for serum biomarker data*. 2019. Accessed July 25, 2022. https://biobank.ndph.ox.ac.uk/showcase/ukb/docs/serum_biochemistry.pdf

27. UK Biobank. *Biomarker assay quality procedures*. 2019. Accessed July 25, 2022. https://biobank.ndph.ox.ac.uk/showcase/ukb/docs/biomarker_issues.pdf

28. UK Biobank. *Genotyping and quality control of UK Biobank, a large-scale, extensively phenotyped prospective resource*. 2015. Accessed June 15, 2022. https://biobank.ctsu.ox.ac.uk/crystal/crystal/docs/genotyping_qc.pdf

29. Bycroft C, Freeman C, Petkova D, et al. The UK Biobank resource with deep phenotyping and genomic data. *Nature*. 2018;562(7726):203-209. doi:10.1038/s41586-018-0579-z

30. Palpatzis E, Bass N, Jones R, Mukadam N. Longitudinal association of apolipoprotein E and sleep with incident dementia. *Alzheimers Dementia*. 2022;18(5):888-898. doi:10.1002/alz.12439

31. Parra KL, Alexander GE, Raichlen DA, Klimentidis YC, Furlong MA. Exposure to air pollution and risk of incident dementia in the UK Biobank. *Environ Res*. 2022;209:112895. doi:10.1016/j.envres.2022.112895

32. Affatato O, Miguet M, Schiöth HB, Mwinyi J. Major sex differences in migraine prevalence among occupational categories: a cross-sectional study using UK Biobank. *J Headache Pain*. 2021;22(1):145. doi:10.1186/s10194-021-01356-x

33. Harrison S, Davies NM, Howe LD, Hughes A. Testosterone and socioeconomic position: Mendelian randomization in 306,248 men and women in UK Biobank. *Sci Adv*. 2021;7(31):eabf8257. doi:10.1126/sciadv.abf8257

34. Textor J, Hardt J, Knüppel S. DAGitty: a graphical tool for analyzing causal diagrams. *Epidemiology*. 2011;22(5):745. doi:10.1097/EDE.0b013e318225c2be

35. Kivipelto M, Mangialasche F, Ngandu T. Lifestyle interventions to prevent cognitive impairment, dementia and Alzheimer disease. *Nat Rev Neurol*. 2018;14(11):653-666. doi:10.1038/s41582-018-0070-3

36. Imai K, Keele L, Yamamoto T. Identification, inference and sensitivity analysis for causal mediation effects. *Statist Sci*. 2010;25(1):51-71. doi:10.1214/10-STS321

37. VanderWeele TJ. Mediation analysis: a practitioner's guide. *Annu Rev Public Health*. 2016;37:17-32. doi:10.1146/annurev-publhealth-032315-021402

38. VanderWeele T. *Explanation in Causal Inference: Methods for Mediation and Interaction*. Oxford University Press; 2015.

39. Tingley D, Yamamoto T, Hirose K, Keele L, Imai K. Mediation: R package for causal mediation analysis. *J Stat Softw*. 2014;59:1-38. doi:10.18637/jss.v059.i05

40. Zhou Z, Ryan J, Ernst ME, et al.; ASPREE Investigator Group. Effect of statin therapy on cognitive decline and incident dementia in older adults. *J Am Coll Cardiol*. 2021;77(25):3145-3156. doi:10.1016/j.jacc.2021.04.075

41. Muldoon MF, Ryan CM, Sereika SM, Flory JD, Manuck SB. Randomized trial of the effects of simvastatin on cognitive functioning in hypercholesterolemic adults. *Am J Med*. 2004;117(11):823-829. doi:10.1016/j.amjmed.2004.07.041

42. Glasser SP, Wadley V, Judd S, et al. The association of statin use and statin type and cognitive performance: analysis of the reasons for geographic and racial differences in stroke (REGARDS) study. *Clin Cardiol*. 2010;33(5):280-288. doi:10.1002/clc.20758

43. Zeki Al Hazzouri A, Jawadekar N, Grasset L, et al. Statins and cognitive decline in the cardiovascular health study: a comparison of different analytical approaches. *J Gerontol A Biol Sci Med Sci*. 2022;77(5):994-1001. doi:10.1093/gerona/glab220

44. Heymann AD, Ravona-Springer R, Moshier EL, Godbold J, Beeri MS. Statin use is associated with better cognitive function in elderly with type 2 diabetes. *J Alzheimers Dis*. 2015;47(1):55-59. doi:10.3233/JAD-142571
system. *Int J Mol Sci*. 2014;15(11):20607-20637. doi:10.3390/ijms151120607

7. U.S. Food and Drug Administration. *Cholesterol-lowering drugs get labeling changes*. 2015. Accessed September 1, 2022. https://www.fda.gov/drugs/special-features/cholesterol-lowering-drugs-get-labelling-changes

8. Power MC, Weuve J, Sharrett AR, Blacker D, Gottesman RF. Statins, cognition, and dementia—systematic review and methodological commentary. *Nat Rev Neurol*. 2015;11(4):220-229. doi:10.1038/nrneurol.2015.35

9. Samaras K, Makkar SR, Crawford JD, et al. Effects of statins on memory, cognition, and brain volume in the elderly. *J Am Coll Cardiol*. 2019;74(21):2554-2568. doi:10.1016/j.jacc.2019.09.041

10. Kemp EC, Ebner MK, Ramanan S, et al.; Alzheimer's Disease Neuroimaging Initiative. Statin use and risk of cognitive decline in the ADNI cohort. *Am J Geriatr Psychiatry*. 2020;28(5):507-517. doi:10.1016/j.jagp.2019.11.003

11. Geifman N, Brinton RD, Kennedy RE, Schneider LS, Butte AJ. Evidence for benefit of statins to modify cognitive decline and risk in Alzheimer's disease. *Alzheimers Res Ther*. 2017;9(1):10. doi:10.1186/s13195-017-0237-y

12. Jamshidnejad-Tosaramandani T, Kashanian S, Al-Sabri MH, et al. Statins and cognition: modifying factors and possible underlying mechanisms. *Front Aging Neurosci*. 2022;14:968039. doi:10.3389/fnagi.2022.968039

13. Sodero AO, Barrantes FJ. Pleiotropic effects of statins on brain cells. *Biochim Biophys Acta Biomembr*. 2020;1862(9):183340. doi:10.1016/j.bbamem.2020.183340

14. Poly TN, Islam MM, Walther BA, et al. Association between use of statin and risk of dementia: a meta-analysis of observational studies. *Neuroepidemiology*. 2020;54(3):214-226. doi:10.1159/000503105

15. Zissimopoulos JM, Barthold D, Brinton RD, Joyce G. Sex and race differences in the association between statin use and the incidence of Alzheimer disease. *JAMA Neurol*. 2017;74(2):225-232. doi:10.1001/jamaneurol.2016.3783

16. Betteridge DJ, Carmena R. The diabetogenic action of statins—mechanisms and clinical implications. *Nat Rev Endocrinol*. 2016;12(2):99-110. doi:10.1038/nrendo.2015.194

17. Kim J, Lee HS, Lee KY. Effect of statins on fasting glucose in non-diabetic individuals: nationwide population-based health examination in Korea. *Cardiovasc Diabetol*. 2018;17(1):155. doi:10.1186/s12933-018-0799-4

18. Mansi IA, Chansard M, Lingvay I, Zhang S, Halm EA, Alvarez CA. Association of statin therapy initiation with diabetes progression: a retrospective matched-cohort study. *JAMA Intern Med*. 2021;181(12):1562-1574. doi:10.1001/jamainternmed.2021.5714

19. Cukierman T, Gerstein HC, Williamson JD. Cognitive decline and dementia in diabetes—systematic overview of prospective observational studies. *Diabetologia*. 2005;48(12):2460-2469. doi:10.1007/s00125-005-0023-4

20. Jain MK, Ridker PM. Anti-inflammatory effects of statins: clinical evidence and basic mechanisms. *Nat Rev Drug Discov*. 2005;4(12):977-987. doi:10.1038/nrd1901

21. Walker KA, Gottesman RF, Wu A, et al. Systemic inflammation during midlife and cognitive change over 20 years: the ARIC Study. *Neurology*. 2019;92(11):e1256-e1267. doi:10.1212/WNL.0000000000007094

22. Mazidi M, Rezaie P, Vatanparast H, Kengne AP. Effect of statins on serum vitamin D concentrations: a systematic review and meta-analysis. *Eur J Clin Invest*. 2017;47(1):93-101. doi:10.1111/eci.12698

23. Goodwill AM, Szoeke C. A systematic review and meta-analysis of the effect of low vitamin D on cognition. *J Am Geriatr Soc*. 2017;65(10):2161-2168. doi:10.1111/jgs.15012

24. Sudlow C, Gallacher J, Allen N, et al. UK Biobank: an open access resource for identifying the causes of a wide range of complex diseases of middle and old age. *PLoS Med*. 2015;12(3):e1001779. doi:10.1371/journal.pmed.1001779

25. Elliott P, Peakman TC, Biobank UK. The UK Biobank sample handling and storage protocol for the collection, processing, and archiving of human blood and urine. *Int J Epidemiol*. 2008;37(2):234-244. doi:10.1093/ije/dym276

26. UK Biobank. *Companion document for serum biomarker data*. 2019. Accessed July 25, 2022. https://biobank.ndph.ox.ac.uk/showcase/ukb/docs/serumhanbiochemistry.pdf

27. UK Biobank. *Biomarker assay quality procedures*. 2019. Accessed July 25, 2022. https://biobank.ndph.ox.ac.uk/showcase/ukb/docs/biomarker_issues.pdf

28. UK Biobank. *Genotyping and quality control of UK Biobank, a large-scale, extensively phenotyped prospective resource*. 2015. Accessed June 15, 2022. https://biobank.ctsu.ox.ac.uk/crystal/crystal/docs/genotyping_qc.pdf

29. Bycroft C, Freeman C, Petkova D, et al. The UK Biobank resource with deep phenotyping and genomic data. *Nature*. 2018;562(7726):203-209. doi:10.1038/s41586-018-0579-z

30. Palpatzis E, Bass N, Jones R, Mukadam N. Longitudinal association of apolipoprotein E and sleep with incident dementia. *Alzheimers Dementia*. 2022;18(5):888-898. doi:10.1002/alz.12439

31. Parra KL, Alexander GE, Raichlen DA, Klimentidis YC, Furlong MA. Exposure to air pollution and risk of incident dementia in the UK Biobank. *Environ Res*. 2022;209:112895. doi:10.1016/j.envres.2022.112895

32. Affatato O, Miguet M, Schiöth HB, Mwinyi J. Major sex differences in migraine prevalence among occupational categories: a cross-sectional study using UK Biobank. *J Headache Pain*. 2021;22(1):145. doi:10.1186/s10194-021-01356-x

33. Harrison S, Davies NM, Howe LD, Hughes A. Testosterone and socioeconomic position: Mendelian randomization in 306,248 men and women in UK Biobank. *Sci Adv*. 2021;7(31):eabf8257. doi:10.1126/sciadv.abf8257

34. Textor J, Hardt J, Knüppel S. DAGitty: a graphical tool for analyzing causal diagrams. *Epidemiology*. 2011;22(5):745. doi:10.1097/EDE.0b013e318225c2be

35. Kivipelto M, Mangialasche F, Ngandu T. Lifestyle interventions to prevent cognitive impairment, dementia and Alzheimer disease. *Nat Rev Neurol*. 2018;14(11):653-666. doi:10.1038/s41582-018-0070-3

36. Imai K, Keele L, Yamamoto T. Identification, inference and sensitivity analysis for causal mediation effects. *Statist Sci*. 2010;25(1):51-71. doi:10.1214/10-STS321

37. VanderWeele TJ. Mediation analysis: a practitioner's guide. *Annu Rev Public Health*. 2016;37:17-32. doi:10.1146/annurev-publhealth-032315-021402

38. VanderWeele T. *Explanation in Causal Inference: Methods for Mediation and Interaction*. Oxford University Press; 2015.

39. Tingley D, Yamamoto T, Hirose K, Keele L, Imai K. Mediation: R package for causal mediation analysis. *J Stat Softw*. 2014;59:1-38. doi:10.18637/jss.v059.i05

40. Zhou Z, Ryan J, Ernst ME, et al.; ASPREE Investigator Group. Effect of statin therapy on cognitive decline and incident dementia in older adults. *J Am Coll Cardiol*. 2021;77(25):3145-3156. doi:10.1016/j.jacc.2021.04.075

41. Muldoon MF, Ryan CM, Sereika SM, Flory JD, Manuck SB. Randomized trial of the effects of simvastatin on cognitive functioning in hypercholesterolemic adults. *Am J Med*. 2004;117(11):823-829. doi:10.1016/j.amjmed.2004.07.041

42. Glasser SP, Wadley V, Judd S, et al. The association of statin use and statin type and cognitive performance: analysis of the reasons for geographic and racial differences in stroke (REGARDS) study. *Clin Cardiol*. 2010;33(5):280-288. doi:10.1002/clc.20758

43. Zeki Al Hazzouri A, Jawadekar N, Grasset L, et al. Statins and cognitive decline in the cardiovascular health study: a comparison of different analytical approaches. *J Gerontol A Biol Sci Med Sci*. 2022;77(5):994-1001. doi:10.1093/gerona/glab220

44. Heymann AD, Ravona-Springer R, Moshier EL, Godbold J, Beeri MS. Statin use is associated with better cognitive function in elderly with type 2 diabetes. *J Alzheimers Dis*. 2015;47(1):55-59. doi:10.3233/JAD-142571
45. Wendell CR, Zonderman AB, Katzel LI, et al. Nonlinear associations between plasma cholesterol levels and neuropsychological function. *Neuropsychology*. 2016;30(8):980-987. doi:10.1037/neu0000298

46. Frank C, Rufini S, Tancredi V, Forcina R, Grossi D, D'Arcangelo G. Cholesterol depletion inhibits synaptic transmission and synaptic plasticity in rat hippocampus. *Exp Neurol*. 2008;212(2):407-414. doi:10.1016/j.expneurol.2008.04.019

47. Liang YJ, Shyu KG, Wang BW, Lai LP. Simvastatin inhibits C-reactive protein-induced pro-inflammatory changes in endothelial cells by decreasing mevalonate pathway products. *Cardiology*. 2008;110(3):182-190. doi:10.1159/000111928

48. Tabrizi R, Tamtaji OR, Mirhosseini N, et al. The effects of statin use on inflammatory markers among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials. *Pharmacol Res*. 2019;141:85-103. doi:10.1016/j.phrs.2018.12.010

49. Adams SP, Tsang M, Wright JM. Lipid-lowering efficacy of atorvastatin. *Cochrane Database Syst Rev*. 2015;2015(3):CD008226. doi:10.1002/14651858.CD008226.pub3

50. Pérez-Castrillón JL, Vega G, Abad L, et al. Effects of atorvastatin on vitamin D levels in patients with acute ischemic heart disease. *Am J Cardiol*. 2007;99(7):903-905. doi:10.1016/j.amjcard.2006.11.036

51. Aloia JF, Li-Ng M, Pollack S. Statins and vitamin D. *Am J Cardiol*. 2007;100(8):1329. doi:10.1016/j.amjcard.2007.05.024

52. Verdoia M, Pergolini P, Rolla R, et al.; Novara Atherosclerosis Study Group (NAS). Impact of high-dose statins on vitamin D levels and platelet function in patients with coronary artery disease. *Thromb Res*. 2017;150:90-95. doi:10.1016/j.thromres.2016.12.019

53. Qin XF, Zhao LS, Chen WR, Yin DW, Wang H. Effects of vitamin D on plasma lipid profiles in statin-treated patients with hypercholesterolemia: a randomized placebo-controlled trial. *Clin Nutr*. 2015;34(2):201-206. doi:10.1016/j.clnu.2014.04.017

54. Krysiak R, Gilowska M, Okopień B. Different cardiometabolic effects of atorvastatin in men with normal vitamin D status and vitamin D insufficiency. *Clin Cardiol*. 2016;39(12):715-720. doi:10.1002/clc.22593

55. Nordestgaard BG, Langsted A, Mora S, et al.; European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) joint consensus initiative. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points-a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. *Eur Heart J*. 2016;37(25):1944-1958. doi:10.1093/eurheartj/ehw152
45. Wendell CR, Zonderman AB, Katzel LI, et al. Nonlinear associations between plasma cholesterol levels and neuropsychological function. *Neuropsychology*. 2016;30(8):980–987. doi:10.1037/neu0000298

46. Frank C, Rufini S, Tancredi V, Forcina R, Grossi D, D'Arcangelo G. Cholesterol depletion inhibits synaptic transmission and synaptic plasticity in rat hippocampus. *Exp Neurol*. 2008;212(2):407–414. doi:10.1016/j.expneurol.2008.04.019

47. Liang YJ, Shyu KG, Wang BW, Lai LP. Simvastatin inhibits C-reactive protein-induced pro-inflammatory changes in endothelial cells by decreasing mevalonate pathway products. *Cardiology*. 2008;110(3):182–190. doi:10.1159/000111928

48. Tabrizi R, Tamtaji OR, Mirhosseini N, et al. The effects of statin use on inflammatory markers among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials. *Pharmacol Res*. 2019;141:85–103. doi:10.1016/j.phrs.2018.12.010

49. Adams SP, Tsang M, Wright JM. Lipid-lowering efficacy of atorvastatin. *Cochrane Database Syst Rev*. 2015;2015(3):CD008226. doi:10.1002/14651858.CD008226.pub3

50. Pérez-Castrillón JL, Vega G, Abad L, et al. Effects of atorvastatin on vitamin D levels in patients with acute ischemic heart disease. *Am J Cardiol*. 2007;99(7):903–905. doi:10.1016/j.amjcard.2006.11.036

51. Aloia JF, Li-Ng M, Pollack S. Statins and vitamin D. *Am J Cardiol*. 2007;100(8):1329. doi:10.1016/j.amjcard.2007.05.024

52. Verdoia M, Pergolini P, Rolla R, et al.; Novara Atherosclerosis Study Group (NAS). Impact of high-dose statins on vitamin D levels and platelet function in patients with coronary artery disease. *Thromb Res*. 2017;150:90–95. doi:10.1016/j.thromres.2016.12.019

53. Qin XF, Zhao LS, Chen WR, Yin DW, Wang H. Effects of vitamin D on plasma lipid profiles in statin-treated patients with hypercholesterolemia: a randomized placebo-controlled trial. *Clin Nutr*. 2015;34(2):201–206. doi:10.1016/j.clnu.2014.04.017

54. Krysiak R, Gilowska M, Okopień B. Different cardiometabolic effects of atorvastatin in men with normal vitamin D status and vitamin D insufficiency. *Clin Cardiol*. 2016;39(12):715–720. doi:10.1002/clc.22593

55. Nordestgaard BG, Langsted A, Mora S, et al.; European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) joint consensus initiative. Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points-a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. *Eur Heart J*. 2016;37(25):1944–1958. doi:10.1093/eurheartj/ehw152