Common Infections Linked to Cognitive Decline in Older Adults

 This gives us no useful information at all; stroke survivors were excluded.

Ask your competent? doctors and hospital when they will get testing done in stroke survivors. No acknowledgement that this is even their responsibility IS ABSOLUTE FUCKING INCOMPETENCE!

Common Infections Linked to Cognitive Decline in Older Adults

Exposure to certain common infections, particularly cytomegalovirus and herpes simplex virus type 2, was linked to poorer executive function in older adults, indicating that chronic infectious exposures may accelerate cognitive aging. Exposure to common infectious agents is associated with domain-specific cognitive impairment among community-dwelling older adults, according to study findings published in Alzheimer’s & Dementia. Evidence regarding the effects of individual pathogens on specific cognitive domains is limited. Researchers from Columbia University and the University of Miami analyzed data from the Northern Manhattan Study to examine whether serologic evidence of infection with 5 common pathogens (herpes simplex virus [HSV]-1, HSV-2, cytomegalovirus [CMV], Chlamydia pneumoniae)was associated with cognitive performance and risk for mild cognitive impairment (MCI) or dementia. The study included 593 participants (mean [SD] age, 71 [8] years; 39% men; 69% Hispanic) who were free of stroke and dementia at baseline. Participants underwent serologic testing for infectious exposures and completed neuropsychological assessments clustered into 4 cognitive domains: memory, language, processing speed, and executive function. Over a mean follow-up of 7.8 years, 30% of participants developed cognitive impairment, and 17% were diagnosed with dementia.…[C]ommon infectious exposures may contribute to cognitive aging and dementia in late life. After adjusting for demographic, vascular, and psychosocial confounders, CMV and HSV-2 seropositivity were significantly associated with poorer executive function (β = -0.29; 95% CI, -0.51 to -0.08;P= .007 and β = -0.19; 95% CI, -0.36 to -0.02;P= .03, respectively), while C pneumoniae seropositivity was linked to reduced language performance (β= -0.17; 95% CI, -0.32 to -0.01; P=.03). In unadjusted models, CMV seropositivity was associated with increased risk for incident MCI (hazard ratio [HR], 1.22; 95% CI, 1.09-1.36;P=.0005) and dementia (HR, 1.18; 95% CI, 1.02-1.37; P= .024). However, these associations were no longer significant after adjustment. Study limitations include reliance on serologic titers, which indicate exposure rather than active infection or reactivation, possible misclassification of infection status over time, and limited power due to few dementia cases. “Taken together, we provide evidence that CMV exposure is associated with decreased executive function and possibly increases risk for cognitive impairment and dementia, adding to a growing body of evidence that common infectious exposures may contribute to cognitive aging and dementia in late life,” the researchers concluded. Disclosures: This research was supported by the National Institutes of Health. Please see the original reference for a full list of disclosures. References:

Link Between Viral Infection(HSV-1/cold sores) and Alzheimer's Emerges in New Data

 

Ask your competent? doctor to test you for this. I had a number of cold sore outbreaks as a kid, no treatment. 

Of course, your incompetent? doctor did nothing with this research from 10 years ago!

Cold sores increases the risk of dementia October 2014 

The latest here?

Link Between Viral Infection and Alzheimer's Emerges in New Data

      Findings implicate HSV-1 but apply only to people with clinical episodes of cold sores

by Judy George, Deputy Managing Editor, MedPage Today May 21, 2025 • 3 min read

Key Takeaways

• People diagnosed with HSV-1 infection had a higher risk of a subsequent Alzheimer's diagnosis.
• Antiherpetic drugs reduced Alzheimer's risk in those diagnosed with HSV-1.
• The findings apply only to people with clinical episodes of cold sores.

People diagnosed with herpes simplex virus type 1 (HSV-1), the virus responsible for cold sores, were more likely to have a subsequent Alzheimer's disease diagnosis, an analysis of U.S. commercial insurance claims suggested.

Across 344,628 Alzheimer's case-control pairs, a history of HSV-1 diagnosis was present in 1,507 people (0.44%) with Alzheimer's disease and 823 matched controls (0.24%), reported Yunhao Liu, PhD, of Gilead Sciences, a pharmaceutical company based in Foster City, California, and colleagues.

This translated to an adjusted odds ratio of 1.80 (95% CI 1.65-1.96), Liu and co-authors wrote in BMJ Openopens in a new tab or window.

Of patients diagnosed with HSV-1, those who used antiherpetic drugs were less likely to develop Alzheimer's compared with those who didn't use antiherpetics (adjusted HR 0.83, 95% CI 0.74-0.92).

"These findings place an even greater emphasis on viewing the prevention of herpesviruses as a public health priority," Liu and colleagues said.

The results confirm previous findings that people with a history of cold sores may have a higher risk of developing Alzheimer's disease, and that this risk may be reduced in people who receive antiviral treatment, noted Alberto Ascherio, MD, DrPH, of the Harvard T.H. Chan School of Public Health in Boston, who wasn't involved with the research.

"This is an observational study based on electronic data of varying quality, so the conclusions cannot be considered definitive," he wrote in a post on the Spanish Science Media Centeropens in a new tab or window website.

"For example, the vast majority of cold sore episodes are not reported in medical records, so the study's conclusions apply to a highly selected subgroup of individuals with clinical episodes of cold sores, perhaps due to clinical severity or the presence of other factors," Ascherio pointed out.

"For this reason, it would be premature for people with cold sores to worry about having an increased risk of Alzheimer's disease," he added. "However, there is growing evidence that viral infections may affect the risk of Alzheimer's disease, and it is important to initiate more definitive research."

At least 22 viruses have been tiedopens in a new tab or window to Alzheimer's, dementia, or other neurodegenerative diseases, and some researchers have proposed that latent viral infectionopens in a new tab or window may provoke Alzheimer's disease. Recent analyses also have linked receiving the herpes zoster (shingles) vaccine with reduced dementia risk in Walesopens in a new tab or window and in Australiaopens in a new tab or window.

Liu and co-authors evaluated diagnostic codes for U.S. patients with records in the IQVIA commercial claims database from 2006 to 2021. They matched patients with an Alzheimer's diagnosis in health records and those without a history of neurologic disease on age, sex, geographical region, database entry year, and number of healthcare visits.

Mean age of the sample was 73 and 65% were women. People with Alzheimer's disease had more comorbidities and a shorter follow-up time compared with controls.

The researchers also identified links between people diagnosed with HSV-2 or varicella zoster virus (chickenpox) and Alzheimer's, but not those diagnosed with cytomegalovirus.

"The molecular mechanisms underlying the role of HSV-1 and other neurotropic viruses in dementia are still not well understood," they observed. Inflammatory alterations in the brain may be important to developing Alzheimer's disease, they noted.

This study captured only a small fraction of the total population with HSV-1 infection, Liu and co-authors pointed out. "Globally, an estimated two-thirds of the population under 50 are infected with HSV-1," they wrote.

The study had other limitations, the researchers acknowledged. People ages 65 and older often are covered by Medicare and are underrepresented in commercial claims data. Due to limited data history, HSV-1 infections prior to the patient's database entry were not included, and some overlap may exist between HSV-1 and HSV-2 diagnoses.

• Judy George covers neurology and neuroscience news for MedPage Today, writing about brain aging, Alzheimer’s, dementia, MS, rare diseases, epilepsy, autism, headache, stroke, Parkinson’s, ALS, concussion, CTE, sleep, pain, and more. Follow

Disclosures

This work was funded by Gilead Sciences.

Liu and most co-authors were employed by and held shares in Gilead. One co-author reported relationships with other pharmaceutical companies.

Primary Source

BMJ Open

Source Reference: opens in a new tab or windowLiu Y, et al "Association between herpes simplex virus type 1 and the risk of Alzheimer's disease: a retrospective case–control study" BMJ Open 2025; DOI: 10.1136/bmjopen-2024-093946.

Cold Sore Virus Linked to Alzheimer’s, Antivirals May Lower Risk

 Ask your competent? doctor to test you for this. I had a number of cold sore outbreaks as a kid, no treatment. 

Of course, your incompetent? doctor did nothing with this research from 10 years ago!

Cold sores increases the risk of dementia October 2014 

The latest here?

 Cold Sore Virus Linked to Alzheimer’s, Antivirals May Lower Risk

Summary: A large study suggests that symptomatic infection with herpes simplex virus 1 (HSV-1)—best known for causing cold sores—may significantly raise the risk of developing Alzheimer’s disease. Researchers found that people with HSV-1 were 80% more likely to have Alzheimer’s, while those treated with antiviral medications had a 17% lower risk.

The findings align with other evidence that HSV-1 may trigger inflammation and amyloid-beta accumulation in the brain, hallmarks of Alzheimer’s pathology. Although the study is observational and can’t prove causation, it highlights the potential for antiviral therapy as a protective strategy and urges greater public health focus on herpes virus prevention.

Key Facts:

• 80% Higher Risk: People with HSV-1 were significantly more likely to develop Alzheimer’s.
• Antiviral Benefit: HSV-1 patients who took antiviral drugs had a 17% lower Alzheimer’s risk.
• Biological Link: HSV-1 may drive brain inflammation and amyloid buildup, contributing to dementia.

Source: BMJ

Symptomatic infection with the virus responsible for cold sores around the mouth–herpes simplex 1, or HSV-1 for short—may have a key role in the development of Alzheimer’s disease, suggests a large pharma industry-funded US study published in the open access journal BMJ Open.

But treatment with antiviral therapy seems to be linked to a lower risk of this type of dementia, suggesting that treatment to quell HSV-1 symptoms may be protective, the findings indicate.

Nearly two thirds (65%) of those with Alzheimer’s disease were women. Credit: Neuroscience News

Currently, around 35.6 million people worldwide live with dementia, and 7.7million new cases are diagnosed every year, say the researchers. Alzheimer’s disease comprises 60%–80% of all dementias, with total costs for its treatment reaching US$305 billion in 2020, they add.

Various infectious agents have been implicated in the development of Alzheimer’s disease, and the most studied of these is HSV-1, which affected more than two-thirds of under 50s around the globe in 2016 alone.

To shed further light on the mooted role of HSV-1 in Alzheimer’s disease and the potential protective effects of antiherpetic drugs, the researchers drew on a large set of US administrative claims data (IQVIA PharMetrics Plus) for the period 2006-21.

People diagnosed with Alzheimer’s disease were matched for age, sex, geographical region, database entry year, and number of healthcare visits with those without any history of neurological disease, resulting in a total of 344,628 case–control pairs.

Nearly two thirds (65%) of those with Alzheimer’s disease were women. Their average age was 73 and they tended to have more co-existing conditions—all risk factors.

In all, 1507 (just under 0.5%) people with Alzheimer’s disease had been diagnosed with HSV-1 (0.44%) compared with 823 (just under 0.25%) of those in the comparison (control) group.

Unsurprisingly, the risk of Alzheimer’s disease rose in tandem with age. But, overall, the likelihood of an HSV-1 diagnosis was 80% higher among those with Alzheimer’s disease, after adjusting for potentially influential factors. 

Among the 2330 people with a history of HSV-1 infection, 931 (40%) used antiherpetic medication after their diagnosis. And they were 17% less likely to develop Alzheimer’s disease than those who didn’t use these treatments.

The researchers also looked at the potential role of other herpes viruses, including HSV-2, varicella zoster virus, and cytomegalovirus. Both HSV-2 and varicella zoster virus infections were also associated with a heightened risk of Alzheimer’s disease.

Exactly how HSV-1 and other neurotropic viruses might heighten the risk of dementia isn’t clear, point out the researchers. 

“However, studies have shown that inflammatory alterations in the brain caused by HSV infection are pivotal in [Alzheimer’s disease] development,” they explain. 

“It has been reported that Aβ peptides are deposited in response to HSV infection and protect host cells by blocking viral fusion with the plasma membrane, pointing to HSV as a potential risk factor for [Alzheimer’s disease]. Consistently, Aβ exhibits antimicrobial properties against various pathogens, including HSV-1,” they add.

HSV-1 DNA is also found in the plaques characteristic of Alzheimer’s disease, and people carrying the ApoE ε4 allele, the most common genetic risk factor for the disease, are more susceptible to HSV infections, they note.

This is an observational study, and as such, no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that HSV-1 infections before the patient’s inclusion in the database weren’t known, added to which many people with the infection don’t have symptoms, while others might not seek treatment when they do–all factors that might influence the findings.

But their findings are in line with those of other studies. And they suggest: “While the molecular mechanisms remain to be fully elucidated, these results are indicative of a possible role for antiherpetic therapy in mitigating dementia risk.”

And they conclude: “These findings place an even greater emphasis on viewing the prevention of herpes viruses as a public health priority. 

About this virology and Alzheimer’s disease research news

Author: Emma Dickinson
Source: BMJ
Contact: Emma Dickinson – BMJ
Image: The image is credited to Neuroscience News

Original Research: The findings will appear in BMJ Open