Study Links Late-Onset Dementia to Certain Infections

Recent research has discovered a potential connection between late-onset dementia and specific infections.

Published in PLOS Medicine, the study delves into whether this association might be related to other health issues caused by serious infections.

Researchers from the University of Helsinki in Finland examined 170 diseases commonly treated in hospitals, looking at occurrences from one to 21 years prior to dementia diagnosis in over 65,000 patients aged 65 and older.

After narrowing it down to 29 diseases with the strongest correlation to dementia, two were identified as infections: cystitis, a type of urinary tract infection, and general bacterial infections. The other diseases included various non-infectious conditions such as mental disorders, digestive issues, endocrine disorders, cardiovascular conditions, neurological diseases, and certain injuries.

Notably, nearly half (47%) of dementia cases followed one of these identified diseases. The researchers noted that the link between dementia and infections persisted even after adjusting for these other diseases, with infections appearing approximately five to six and a half years before a dementia diagnosis.

Individuals with hospital-treated cystitis or bacterial infections had about a 19% increased likelihood of developing late-onset dementia. The study’s findings suggest a possibility that severe infections could heighten dementia risk.

The authors indicated that the process of developing dementia often spans years or even decades, leading them to speculate that severe infections might speed up existing cognitive decline.

However, there were some limitations, including a lack of baseline cognitive assessments and clinical data before dementia diagnoses, as well as missing treatment data for infections.

Co-author Pyry N. Sipila, MD, PhD, pointed out that the study was observational in nature. He mentioned, “We can’t definitively establish a cause-and-effect relationship between severe infections and dementia.” He also highlighted the need for future intervention trials to explore whether preventing infections might help delay or reduce dementia onset.

He encouraged adults to stay updated on vaccinations, acknowledging that while the study does not prove vaccinations prevent dementia, there could be benefits in potentially lowering risk.

Dr. Joel Salinas, a behavioral neurologist, noted that the study’s size could make the findings relevant across various populations. He remarked that “the severe infections seem to play an independent role” rather than just being markers for overall health risk.

Salinas further emphasized the need to view the increased risk in context. An infection alone doesn’t guarantee dementia development; rather, it is just one part of a larger puzzle of factors contributing to dementia. Key risk factors include heart disease, hypertension, diabetes, depression, and head injuries.

In summary, this research serves as a reminder that severe infections, especially those requiring hospitalization, might be an additional aspect of dementia risk, particularly in older adults. The understanding of dementia is evolving from seeing it as a singular disease toward recognizing it as a product of many interacting factors over time.