Recent studies have found a connection between late-onset dementia and certain infections. This research, published in PLOS Medicine, delved into whether the observed relationship might be influenced by other health complications that arise from severe infections.
Researchers from the University of Helsinki looked at 170 common diseases treated in hospitals that occurred anywhere from one to 21 years prior to a dementia diagnosis among over 65,000 patients aged 65 and older.
From their analysis, they identified 29 diseases that had the strongest links to dementia, with two of them being infections: cystitis (which is a bacterial urinary tract infection) and general bacterial infections.
In addition to infections, the remaining conditions included various non-infectious diseases, such as mental health disorders, digestive and cardiovascular issues, as well as injuries.
About 47% of dementia cases were preceded by one of the 29 identified diseases. Interestingly, even after accounting for these other diseases, the researchers found a persistent connection between dementia and infections, which tended to occur roughly five to six and a half years before the dementia diagnosis.
Those who had experienced cystitis and bacterial infections had around a 19% higher rate of late-onset dementia. The findings suggest that serious infections could potentially increase the risk of developing dementia.
The progression of dementia typically spans years or even decades, leading the authors to propose that severe infections might accelerate a decline in cognitive function.
However, there were some limitations to the study, like a lack of initial cognitive assessments and clinical examination data before dementia diagnoses. Treatment data for infections was also missing.
Co-author Pyry N. Sipila, a public health lecturer, emphasized that the study was observational. He noted that they cannot definitively conclude a cause-and-effect relationship between severe infections and dementia. He suggested that future intervention trials might explore whether preventing infections could reduce or delay dementia onset.
He also recommended that adults keep their vaccinations up to date. While the study doesn’t prove that vaccinations can prevent dementia, he believes they may offer benefits, including potentially lowering risk.
Dr. Joel Salinas, a neurologist, highlighted that the size of the study could lend itself to broader applicability. He pointed out that while infections are often seen as signs of general health risks, the findings show that severe infections might play an independent role in dementia risk.
Salinas further noted the need to keep this increased risk in perspective; having an infection doesn’t mean dementia is inevitable, but it should be viewed as part of a larger puzzle. Major risk factors for dementia include heart disease, hypertension, diabetes, and head injuries.
He concluded by stating that this research serves as a reminder that serious infections that require hospitalization may also factor into dementia risk, particularly in older adults. It reinforces the shift from viewing dementia as a singular disease to recognizing it as a complex interplay of various factors over time.
