The Infection Factor: Rethinking Heart Disease and Dementia

Ask most healthcare professionals what causes heart attacks and strokes and you will be told that cardiovascular disease (CVD) is triggered by too much cholesterol and related lipid compounds circulating in the bloodstream. LDL (low-density lipoprotein aka “bad“) cholesterol has been a particular target. Drug companies spent decades developing highly effective medications to lower cholesterol. That’s why about 50 million Americans take statin-type medications to lower their LDL cholesterol. There’s one big problem, though. Heart disease remains our number one killer after more than half a century of lipid-lowering medications. Is it time to start rethinking heart disease, strokes and dementia?

Why Haven’t we Won the War Against CVD?

Old dogmas die hard. For decades, cardiovascular disease (CVD) was blamed almost exclusively on cholesterol that clogged arteries in the heart and brain. Cardiologists and neurologists focused primarily on drugs that lower cholesterol and reduce blood pressure.

Drug companies have been happy to oblige. We have dozens of powerful medications that are very effective at controlling both risk factors. And yet the top 3 killers in the US remain:

• Heart disease
• Cancer
• Stroke

As already mentioned, heart disease remains our # 1 killer even though we have amazingly successful drugs to lower LDL cholesterol. Atorvastatin is the most prescribed drug in the US. Nearly 30 million people take it.

Strokes are also common. According to the CDC, nearly 800,000 people have a stroke annually. At last count, “…1 in 6 deaths (17.5%) from cardiovascular disease was due to stroke.”

A recent analysis from the National Center for Health Statistics (online, August 2024) reports:

“After declines between 2002 and 2012, stroke death rates for adults ages 45–64 increased 7% between 2012 (20.2 per 100,000) and 2019 (21.7) and an additional 12% through 2021 (24.4).”

How could this be? How could strokes have increased even though we have highly useful cholesterol-lowering medications and more people are taking them than ever before? And we have lots of blood pressure lowering drugs. Over 75 million people are taking meds such as lisinopril, amlodipine, losartan, hydrochlorothiazide (HCTZ), metoprolol and spironolactone. Why haven’t we seen a dramatic decrease in both heart attacks and strokes?

Infections: Rethinking Heart Disease and Brain Breakdown:

More than 25 years ago we interviewed a fascinating evolutionary biologist, Paul Ewald, PhD. He had written two impressive books: The Evolution of Infectious Disease and Plague Time: The New Germ Theory of Disease.

The last we checked, Dr. Ewald was Director of the Program in Evolutionary Medicine in the Department of Biology at the University of Louisville. He alerted physicians to the strong possibility that infectious contribute to many of our most challenging chronic diseases. Sadly, he seems to have been mostly ignored by cardiologists and neurologists.

When you put all your chips on LDL cholesterol as the primary cause of heart heart attacks and strokes, it’s hard to consider alternatives. Ditto when it comes to amyloid beta and Alzheimer’s disease. Surprisingly, infectious disease experts have seemingly been reluctant to consider infectious diseases as the culprit behind many chronic diseases.

Chronic Fatigue Syndrome (CFS):

Mainstream medicine resisted the idea that chronic fatigue syndrome was triggered by infection. We interviewed Paul Cheney, MD, PhD, in 1988 on The People’s Pharmacy radio show. He described a cluster of patients who had experienced respiratory tract infections. They went on to develop overwhelming fatigue that lingered. Dr. Cheney’s research was not welcomed by infectious disease experts or mainstream medicine. You can read more about CFS and Dr. Paul Cheney at this link.

We now think there are enough data to support Dr. Ewald’s hypotheses. If we don’t start rethinking heart disease and dementia, we are not likely to make much progress.

Why It Is Crucial to Start Rethinking Heart Disease:

If what you are doing isn’t working that well, perhaps it’s time to look for other explanations. What would you do if you had to turn the ignition of your car 99 times before it finally started on the 100th try. You would not put up with such a dismal situation. Most people would demand that the car be fixed…and fast!

We have cited a famous Lipitor (atorvastatin) ad many times. It stated in large print that Lipitor lowered the risk of heart attacks by 36 percent. For physicians and patients that looked fabulous. But the asterisk beside that number revealed something quite different:

“That means in a large clinical study, 3 percent of patients taking a sugar pill or placebo had a heart attack compared to 2 percent of patients taking Lipitor.”

Sounds a lot like 1 person out of 100 avoided a heart attack after five years of taking Lipitor. And these were high-risk heart patients. You can read more about misleading math at this link.

Infectious Diseases and Cardiovascular Disease (CVD):

There is growing evidence that infections contribute to cardiovascular complications. A systematic review found evidence that influenza can lead to heart attacks and strokes. SARS-CoV-2 (the virus that causes COVID-19), respiratory syncytial virus (RSV) and Coxsackie B virus may all trigger heart attacks (Cardiovascular Research, June 17, 2025).

The authors describe their conclusions:

“Myocardial infarction [heart attack] and stroke remain the world’s two leading causes of premature death. Given the critical, life-threatening nature of these events, knowledge of viral triggers to inform policies that may reduce AMI [acute myocardial infarction] and stroke represents a global health priority…We present a comprehensive systematic review including meta-analysis of pathogen-specific associations with AMI and stroke, incorporating comprehensive database coverage and a highly inclusive search spanning over 40 years of literature. This study adds new knowledge by providing a comprehensive picture of the role of multiple respiratory viruses and the pathogens most strongly associated with each outcome.

“Common, often vaccine-preventable, respiratory viruses play a role in precipitating acute cardiovascular events. The strength of association and certainty of evidence varies across different causal pathogens, with SARS-CoV-2 and influenza being the most strongly associated triggers.”

Urinary Tract Infections: Rethinking: Rethinking Heart Disease!

In a separate study, scientists analyzed medical records in Wales (BMJ Open, June 30, 2025). They discovered that 4.5 to 5 percent of patients admitted with a heart attack or stroke between 2010 and 2020 had a confirmed urinary tract infection UTI). The investigators suggest that perhaps the inflammatory response to an acute infection sparks cardiovascular consequences.

Please hit your internal pause button. Have you ever heard that there could be a connection between a UTI and heart attacks or strokes? I didn’t think so.

Here is how the authors introduce their research:

“Myocardial infarction (MI) and stroke are leading causes of mortality. Alongside well-established modifiable risk factors such as hypertension, low-density lipoprotein cholesterol and tobacco smoke, there is increasing interest in the role of acute infection in the pathogenesis of cardiovascular disease. Excess mortality from cardiovascular disease during influenza epidemics was first reported in the 1930s, but more robust associations between acute infections and acute cardiovascular events were only appreciated over the past few decades.

Main Finding:

“In this SCCS [self-controlled case series], we found that microbiologically confirmed UTIs were associated with an increased risk of MI and stroke. The risk of MI was highest in the first 7 days after UTI, with a further period of increased risk 15–28 days after UTI. The risk of stroke was also highest in the first 7 days after UTI and was raised 29–90 days after UTI.”

Comparisons to Other Research:

“The link between respiratory tract infections and MI or stroke has been well established. Studies of influenza, respiratory syncytial virus [RSV], pneumonia and other respiratory viruses have found an increased risk of acute MI in the 1–3 days following a respiratory tract infection, with the effect sizes ranging from a threefold to sixfold increase according to the infecting organism. Several studies have also observed an association between pneumonia and acute cardiovascular events (including MI and stroke). The link with UTI has been less well studied.”

Rethinking Heart Disease: Potential Mechanisms

Why would the flu, RSV, pneumonia, COVID or urinary tract infections increase the risk for heart attacks and strokes. The authors of the UTI research offered several mechanisms:

• Atherosclerotic plaque is common in arteries. It is usually pretty stable because it is made up of a chalk-like material (calcium carbonate). These authors propose that the infectious process “destabilizes” this plaque as a result of inflammation.
• If arterial plaque becomes “destabilized” it is more likely to fracture and lead to a blood clot that could block the artery.
• An increase in heart rate might also contribute to this chain of events leading to a heart attack or stroke.

Blood Stream Infections and CVD:

The idea that an upper respiratory tract infection just affects the nose or the lungs is somewhat short sighted. Pathogens can spill over into the blood stream. Even when an infection remains localized in the airways, the inflammatory reaction of the body can affect blood vessels.

There appears to be a clear link between bloodstream infections and cardiovascular events (Open Heart, March 25, 2025). The authors of this research conclude:

“In this population-based study, we found community-associated BSI [blood stream infections] to be associated with incident MI and stroke. Risk was highest in the first 7 days after BSI and largely normalised 28-days after infection. Risk was clearly associated with the magnitude of the inflammatory response, whereby patients with the highest CRP [C-reactive protein] concentrations were at the greatest risk of CVD events. Intriguingly, our results also suggest a possible protective effect of aspirin and statins.”

Long-Lasting Risks: Rethinking Heart Disease

Most people think of a respiratory infection as a brief interlude of ill health. Once it passes, you can go on about your business without worry.

Scientists have found evidence to the contrary, however. People who caught chicken pox as children harbor the varicella-zoster virus in the spinal column and brain for decades. It can reemerge as shingles later in life. Research has found that there is a link between shingles and heart attacks, TIAs (transient ischemic attacks) and strokes (Neurology, Jan. 21, 2014).

Periodontal Disease and Rethinking Heart Disease:

Another link between infection and cardiovascular disease is gum disease. Periodontitis is chronic inflammation of the gums around the teeth. Bacteria build up in dental plaque, release toxins and provoke an immune response.

Researchers have known for decades that people with periodontal disease are more prone to cardiovascular disease (Periodontology 2000, Nov. 23, 2023). Scientists are still figuring out how pathogens in the gums affect blood vessels in the heart and brain (Cellular Signaling, Aug. 2025).

Micro-organisms that start in the mouth may travel to blood vessels and trigger inflammation that damages the lining of those tissues. The authors point out that improved oral health care could represent a new way to prevent and treat heart disease.

Vaccination vs CVD: Rethinking Heart Disease and Strokes!

Another approach that could reduce the burden of heart disease and stroke is vaccination. Immunizing people against influenza, RSV and shingles can help protect them from the chance of cardiovascular catastrophe as well as infection (Atherosclerosis, June 13, 2025; International Journal of Infectious Diseases, July 31, 2025; Clinical Infectious Diseases, Aug. 9, 2025).

Several studies have shown that people vaccinated against shingles are also at lower risk for developing dementia (Nature, April 2, 2025; JAMA, April 23, 2025).

The authors of the JAMA study conclude:

“By taking advantage of a quasi-experiment and corroborating findings from Wales in a different population, this study provides evidence of the potential benefits of HZ [herpes zoster or shingles] vaccination for dementia that is more likely to be causal than that of more commonly conducted associational studies.”

Final Words:

Such research is challenging neuroscientists who have not been considering infection as a contributing factor to Alzheimer disease. It may be time for cardiologists and neurologists to start collaborating with infectious disease experts to address heart disease, stroke and dementia.

Should you wish to learn more about these issues, here are some articles we have written that you might find helpful:

Shingles Vax Reduces Risk of Heart Attack, Stroke, and Alzheimer’s!

Could You Develop Heart Disease from Tick Bites or COVID?

How COVID and Many Other Infections Cause Heart Disease

Will Gum Disease Boost Your Risk for Dementia?

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