Finnish Study Finds Severe Infections Independently Linked to Higher Dementia Risk

Severe infections are independently linked to a higher risk of dementia, according to a 2026 Finnish study.

Researchers analyzed over 62,500 people in Finland aged 65 or older who were diagnosed with late-onset dementia between 2017 and 2020. They compared them to a control group of more than 312,700 participants without dementia.

The study identified nearly 30 hospital-treated diseases occurring 1-21 years before a dementia diagnosis that were associated with an approximately 20% higher risk. Key infectious diseases included cystitis and bacterial infections at unspecified sites.

People with cystitis had a 22% higher chance of dementia after adjusting for other comorbidities. Those with bacterial infections had a 19% increased risk. The association was stronger for cases of early-onset dementia.