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Severe infections requiring hospital treatment were found to occur 5-6 years prior to many dementia diagnoses. Credit: Neuroscience News<\/p>\nSummary: A large-scale study has found that severe, hospital-treated infections are significantly associated with an increased risk of dementia. By analyzing nationwide Finnish health registry data of over 374,000 individuals, researchers identified 29 diseases linked to dementia risk\u2014including 27 non-infectious conditions like Parkinson\u2019s and alcohol-related disorders.<\/p>\n
Crucially, the link between infections (such as urinary tract infections and unspecified bacterial infections) and dementia remained strong even after adjusting for these other 27 health conditions. The researchers suggest that while they cannot yet prove a direct cause-and-effect relationship, severe infections may accelerate underlying cognitive decline in the years leading up to a diagnosis.<\/p>\n
Key Facts<\/p>\n
Independent Risk: Less than one-seventh of the dementia risk associated with severe infections could be attributed to other pre-existing health conditions, suggesting infections are a standalone risk factor.The Five-Year Window: On average, dementia-related infections occurred 5 to 6 years before a formal dementia diagnosis.Early-Onset Vulnerability: The link was even stronger for those diagnosed with dementia before age 65, with five types of infections\u2014including pneumonia and dental caries\u2014showing a significant association.Specific Infection Triggers: Hospital-treated cystitis (UTIs) and bacterial infections of unspecified sites were the most robustly linked to late-onset dementia.<\/p>\n
Source: PLOS<\/p>\n
Severe infections increase the risk of dementia independently of other coexisting illnesses, according to a new study published March 24th\u00a0in the open-access journal\u00a0PLOS Medicine\u00a0by Pyry Sipil\u00e4 of the University of Helsinki, Finland, and colleagues.<\/p>\n
Severe infections have been linked to an increased risk of dementia. However, it has been unclear whether this association is explained by other coexisting, non-infectious diseases that predispose people to both infections and dementia.<\/p>\n
Severe infections requiring hospital treatment were found to occur 5-6 years prior to many dementia diagnoses. Credit: Neuroscience News<\/p>\n
In the new study, researchers used nationwide Finnish health registry data covering more than 62,000 individuals aged 65 or older who were diagnosed with late-onset dementia between 2017 and 2020, along with more than 312,000 matched dementia-free controls.<\/p>\n
Taking a broad approach, they examined all hospital-treated diseases recorded during the previous twenty years, identifying 29 diseases that were robustly associated with increased dementia risk. Nearly half (47%) of dementia cases had at least one of the 29 identified diseases before their diagnosis.<\/p>\n
Of those diseases, two were infections: cystitis (a urinary tract infection) and bacterial infection of an unspecified site. Among the non-infectious diseases, the strongest associations with dementia were seen for mental disorders due to brain damage or physical disease, Parkinson\u2019s disease, and alcohol-related mental and behavioral disorders.<\/p>\n
When the researchers then adjusted for all 27 non-infectious dementia-related diseases identified, the association between both infections and dementia remained largely intact. Less than one-seventh of the excess dementia risk among individuals with hospital-treated cystitis or bacterial infections was attributable to pre-existing conditions.<\/p>\n
The link between infections and dementia was even stronger for early-onset dementia (diagnosed before age 65), where five types of infection\u2014including pneumonia and dental caries\u2014were associated with elevated risk.<\/p>\n
The study was limited by the lack of baseline cognitive assessments and clinical examination data before dementia diagnoses, as well as a lack of data on infection treatments.<\/p>\n
\u201cOverall, our findings support the possibility that severe infections increase dementia risk; however, intervention studies are required to establish whether preventing or effectively treating infections yields benefits for dementia prevention,\u201d the authors say.<\/p>\n
The authors add, \u201cWe found 27 diverse severe, hospital-treated diseases that were robustly associated with an increased risk of dementia. Two of these diseases were infections, namely urinary tract infections and unspecified bacterial infections.\u201d\u00a0<\/p>\n
\u201cIn our study, dementia-related infections occurred on average 5 to 6 years before dementia diagnosis. Given that the development of dementia often takes years or even decades, these findings suggest that severe infections might accelerate underlying cognitive decline.<\/p>\n
\u201cHowever, as these findings were observational, we cannot exclude the possibility that some unmeasured confounding factors might also have affected our findings. Thus, we cannot prove cause and effect.\u201d<\/p>\n
\u201cIdeally, intervention trials should examine whether better infection prevention helps reduce dementia occurrence or delay the onset of this disease.\u201d<\/p>\n
Key Questions Answered:Q: Does having a minor infection like a cold increase my dementia risk?<\/p>\n
A: This study specifically looked at severe, hospital-treated infections. While everyday sniffles weren\u2019t the focus, the data suggests that infections severe enough to require significant medical intervention are the ones linked to future cognitive decline.<\/p>\n
Q: Why would a UTI or a tooth infection affect my brain?<\/p>\n
A: Researchers believe severe infections cause systemic inflammation. This \u201cbiological storm\u201d can cross into the brain, potentially damaging neurons or accelerating the buildup of plaques already present in the early, silent stages of dementia.<\/p>\n
Q: Can I lower my dementia risk by treating infections faster?<\/p>\n
A: It\u2019s a strong possibility. The researchers are calling for new trials to see if better infection prevention and more aggressive treatment can actually delay or prevent the onset of dementia in high-risk groups.<\/p>\n
Editorial Notes:This article was edited by a Neuroscience News editor.Journal paper reviewed in full.Additional context added by our staff.About this neurology research news<\/p>\n
Author:\u00a0Claire Turner<\/a>
Source:\u00a0PLOS<\/a>
Contact:\u00a0Claire Turner \u2013 PLOS
Image:\u00a0The image is credited to Neuroscience News<\/p>\n