Flu Shots and Dementia Risk

Getting your yearly flu vaccination might have an unexpected bonus: it could help guard against dementia.

Several studies indicate that older individuals who received flu shots had a reduced risk of developing dementia over time compared to those who skipped the vaccine. One particular study noted a reduction in risk by as much as 40 percent.

Recent research, published this month, adds weight to these claims. It shows that older adults receiving a higher dose of the flu vaccine—usually recommended for those 65 and older—had an even lower likelihood of developing Alzheimer’s disease than those who received the standard dose.

Other medications have also been linked to a reduced risk of dementia. However, the real conundrum lies in figuring out if these drugs are directly helping the brain or if it’s merely a correlation.

Take the flu vaccine, for example. “People who typically get vaccinated often see their doctors regularly and follow treatment for conditions like high blood pressure and cholesterol, which also lower Alzheimer’s risk,” notes Dr. Paul Schulz, a neurologist at UTHealth Houston who led the study. Yet, since everyone in the study received the flu vaccine, and the higher dose seemed to provide more protection, Dr. Schulz suggests that it’s likely the vaccine itself, not just patient behavior, that is reducing risk.

Scientists are looking into several other medications that may also decrease dementia risk.

Shingles Vaccine

There’s considerable enthusiasm surrounding the shingles vaccine, backed by robust research. Studies worldwide reveal that individuals who have received the vaccine often experience a 15 to 20 percent lower risk of developing dementia. Much of this research pertains to older versions of the vaccine, but initial findings suggest that Shingrix, a newer formulation commonly used in the U.S., could potentially offer even greater protection, particularly for women.

Researchers are optimistic that the vaccine itself provides this protection, as its introduction in certain countries served as a sort of natural clinical trial.

“At this point, the evidence seems to support a cause-and-effect relationship,” states Dr. Pascal Geldsetzer, an epidemiologist working on related research.

There are a couple of theories as to how vaccines might contribute to a reduced risk of dementia. One idea is that by preventing infections, vaccines hinder the immune response and the related inflammation, which is known to contribute to dementia. This is particularly significant for shingles, as the associated virus can lead to inflammation in the brain.

Additionally, vaccines might influence the immune system in ways that directly safeguard the brain.

Cholesterol and Blood Pressure Medications

Several studies suggest that medications like statins and hypertension treatments are linked to a 10 to 15 percent reduced risk of dementia.

Many researchers believe these drugs protect the brain by managing risk factors such as blood pressure and cholesterol, both known contributors to dementia. Yet, similar to vaccines, those who consistently take their medications might engage in other healthy habits that help lower their risk.

The majority of research remains observational, although a handful of clinical trials have aimed to take a closer look at the connection. The results have been mixed. A trial from China in 2025 showed that individuals with high blood pressure who took hypertension medication experienced lower dementia rates four years later. In contrast, a 2009 trial involving statins did not indicate preventive benefits for cognitive decline among participants with vascular disease risks.

Questions remain about whether individuals without cardiovascular issues might benefit from these medications primarily for dementia prevention. Two large trials are currently exploring the potential of statins in this context.

Anti-Inflammatory Drugs

Given that inflammation in the brain has been identified as a contributor to Alzheimer’s, some experts suggest anti-inflammatory medications could possibly protect the brain by decreasing both systemic and brain inflammation. A recent review highlighted anti-inflammatories as potentially beneficial in reducing dementia risk.

David Llewellyn, a professor at the University of Exeter Medical School, believes the scientific basis for this is compelling.

Nevertheless, studies examining the relationship—particularly with nonsteroidal anti-inflammatory drugs—have produced inconsistent results. While some research points to a lower dementia risk from ibuprofen usage, others show no correlation or even an increased risk. A Cochrane review from 2020 concluded that there’s no supporting evidence for using aspirin or NSAIDs to prevent dementia.

Diabetes Drugs

Since diabetes correlates with an elevated risk of dementia, several medications for Type 2 diabetes, like metformin and SGLT2 inhibitors, seem to modestly lower that risk, although not all studies agree.

The hypothesized benefit mainly relates to how these medications control insulin and blood sugar levels, which can influence the health of brain cells. Some animal studies also suggest these drugs may help reduce inflammation and possibly lower levels of amyloid beta, a crucial protein involved in Alzheimer’s.

Clinical trials are ongoing to determine whether these diabetes medications can genuinely aid in dementia prevention.

Additionally, some observational studies have found that diabetes patients taking newer GLP-1 medications had up to a 45 percent lower risk of developing Alzheimer’s. However, recent clinical trials exploring whether the oral version of Ozempic might slow cognitive decline found no benefit, leading to a significant decrease in enthusiasm around the potential of GLP-1s as Alzheimer’s treatments. More research is certainly needed to clarify their actual impact on dementia risk.