The current estimate of Alzheimer’s disease (AD) prevalence in the US exceeds 6 million people. While some evidence suggests that incidence of dementia may be decreasing due to improvements in average cardiovascular health, the number of affected individuals is growing because of our aging population.
Most treatments available for AD offer limited symptomatic relief. That is why the identification of factors that can be modifiable is essential for the prevention or delay of AD.
Studies have shown an association between influenza vaccination and the incidence of AD. However, most studies have been limited to small sample sizes.
Recently, a team of researchers from the McGovern Medical School at UTHealth Houston compared the risk of AD incidence between patients with and without prior flu vaccination in a large nationwide sample of U.S. adults. The results appear in the Journal of Alzheimer’s Disease.
40% Reduction Risk for Alzheimer’s Disease
The team analyzed data from 935,887 flu-vaccinated patients and 935,887 non-vaccinated patients. Eligible patients were free of dementia during the 6-year look-back period and≥65 years old by the start of follow-up.
The researchers used a propensity-score matching to create the cohorts with similar baseline demographics, medication use, and comorbidities.
During the follow-up period 5.1% (n = 47,889) of the flu-vaccinated patients and 8.5% (n = 79,630) of the flu-unvaccinated patients developed AD.
The study revealed that patients who received at least one influenza vaccine were 40% less likely than their non-vaccinated peers to develop incident AD during the 4-year follow-up period. The team concluded that influenza vaccination is associated with a reduced risk of AD. However, the mechanism by which this happens requires further study.
Avram S. Bukhbindera, et al. Risk of Alzheimer’s Disease Following Influenza Vaccination: A Claims-Based Cohort Study Using Propensity Score Matching. 2022. Journal of Alzheimer’s Disease. DOI: 10.3233/JAD-220361.