Statins and Alzheimer’s: What Impact Do Statins Have on Dementia?

Statins and Alzheimer’s disease: What impact do statins have on dementia and progression of Alzheimer’s disease?

Statins have been variable linked with dementia progression. However recent studies have found that statins may slow the progression of dementia rather than accelerating the disease process.

However, it’s very difficult to study the impact of statins on dementia caused by stroke or other diseases that affect the brain as these conditions can cause dementia, and statins are used to treat these conditions too.

Even in patients treated for Alzheimer’s disease, medications such as antipsychotics and antidepressants are commonly used which can also cause dementia.

Despite all the confounders, statins can theoretically improve memory and may delay the progression of dementia. 

This has been proved in a recent study published in BMC on 20th December 2023. Here are some of the highlights of the study:

Statins and Alzheimer’s Disease: Highlights of the Study

1. In three years, the use of statins showed improved cognitive function in people with Alzheimer’s disease (AD) or mixed dementia.
2. Simvastatin users who were younger (<79.5 years) benefited cognitively more than younger atorvastatin users.
3. Based on statin lipophilicity, the study did not find any significant changes, suggesting that this attribute did not affect the cognitive advantages.
4. While the study suggests cognitive benefits for some AD or mixed dementia patients using statins, there is a need for additional research.

An imbalance in cholesterol levels in the brain is linked to dementia, particularly Alzheimer’s disease (AD), and disruptions may contribute to AD development.

Cholesterol plays a role in maintaining brain function, and disturbances in its homeostasis could impact nerve cells.

The precise mechanisms are not fully comprehended, but keeping optimal cholesterol levels in the brain is important in improving cognitive abilities.

Statins are drugs that decrease cholesterol levels by inhibiting an enzyme crucial for cholesterol production in the liver.

By blocking this enzyme, statins reduce the amount of cholesterol synthesized, stimulating the liver to take up more cholesterol from the bloodstream.

This leads to a decrease in overall cholesterol levels, mainly low-density lipoprotein (LDL) cholesterol.

A recent study explored the connection between statin use and dementia and AD. These drugs can potentially lower the cholesterol that is associated with causing plaques in the brain.

This research has suggested that lipid-lowering meds can be beneficial for cognition in patients with AD and mixed dementia. [ref]

Even though this is encouraging for clinicians, there is still a need for further research to study the metabolism behind this effect.

Study methodology:

The study aimed to understand the relationship between cholesterol-lowering drugs and cognitive decline in patients with Alzheimer’s and mixed dementia.

Researchers looked at patients in Sweden with Alzheimer’s disease or mixed dementia who needed cholesterol-lowering treatment.

Information was collected from the Swedish Registry for Dementia (SveDem), a nationwide database.

They included 15,586 patients and tracked them until they passed away, moved away, or until October 16, 2018.

Patients who had previously had high cholesterol and those who were prescribed cholesterol-lowering medications were the focus of the research.

Furthermore, they examined how cognition changes over time in three groups:

1. people taking statins versus people who do not.
2. people taking statins of different kinds.
3. people taking other cholesterol-lowering drugs.

Data included medication use, comorbidities (other health conditions), and covariates (factors like age and sex).

The primary outcome measured was cognitive decline using MMSE (Mini-Mental State Examination) scores.

They used statistical models to analyze the data, considering factors like medication use, comorbidities, and patient characteristics.

They also adjusted for potential biases and conducted sensitivity analyses to ensure good results.

Study analysis:

In this study of 15,586 patients, primarily women with an average age of 79.5, they observed a positive cognitive impact associated with statin use.

Taking one daily dose of statins, on average, correlated with a gain of 0.63 cognitive test points after 3 years compared to non-users.

Notably, simvastatin users, especially those younger than 79.5 years, showed even greater cognitive improvement than atorvastatin users.

No significant differences were found based on statin type, but the results were less consistent for new statin users in sensitivity analysis. Further research is crucial to confirm these findings and understand their implications.

Limitations of this research:

The study has limitations. It is observational, so causation cannot be established. Because the data was taken from registries, there is a high chance of inaccurate information. Missing MMSE scores and the assumption of adherence to prescribed medications pose challenges.

The study’s average follow-up duration is relatively short. Also, it lacks genetic data and does not consider lifestyle factors. The observed cognitive benefits may be influenced by unknown characteristics.

Results in incident statin users may be affected by prescription timing. So, confirmation through further research, where all these limitations are addressed, is crucial.

Statins and Alzheimer’s: The bottom line

This isn’t the first time researchers have explored the connection between cholesterol and dementia or AD.

Research published earlier this year also concluded that people with high fluctuations in cholesterol levels are at great risk of AD or dementia. [ref]

So, there is clearly a connection between both components, but it needs to be thoroughly studied as most research has its limitations.

Nevertheless, you can choose to take statins for the sake of cognitive functions, but it is advised to consult your doctor before taking any steps.