Why AFib Patients Have Higher Rates of Cancer (and What It Tells You About the Cause)

AFib patients get more cancer.

This is not my guess. It shows up in every large cohort that has been looked at. In the Women’s Health Study, AFib patients had a 48% higher risk of a later cancer diagnosis. In Denmark, men with new AFib had a 41% higher cancer risk. In a 2026 analysis of 1.4 million matched patients, patients diagnosed with AFib between 30 and 50 had almost three times the cancer risk of people without it.

Soooo, what is going on??

For starters….AFib does not cause cancer and cancer does not cause AFib. They share common root causes.

As I have mentioned many times, virtually every disease comes from chronic inflammation and oxidative stress. The same processes that scar and fibrose the atrium also damage DNA everywhere else. The risk factors are the same as with every AFib patient: insulin resistance, obesity, sleep apnea, alcohol, gum disease, leaky gut, environmental toxins, poor sleep and chronic stress.

A Taiwanese study makes the point for me. AFib patients with one of those risk factors had a 40% higher cancer risk. With six of them, five times higher.

This is why I no longer think of AFib as an electrical problem to be ablated. I can ablate the rhythm, and I did for years. I cannot ablate the inflammation that produced it.

What the studies actually show

Women’s Health Study (JAMA Cardiology, 2016). 34,691 healthy women followed for a median of 19 years. Women who developed AFib had a 48% higher risk of a later cancer diagnosis after adjustment, and the risk was still elevated more than a year after the AFib diagnosis.

Danish Diet, Cancer and Health cohort (JAHA, 2018). About 55,000 people. New AFib carried a 41% higher cancer risk in men and 15% in women. In men, lung cancer was up 66% and colorectal cancer 37%.

Taiwan nationwide cohort. 332,555 AFib patients. Cancer incidence was 37% above the general population, highest in the first year and still 18% higher more than ten years after the AFib diagnosis. AFib patients with one metabolic or inflammatory risk factor had a 40% higher cancer risk than those with none; with six risk factors the risk was five times higher.

TriNetX real-world dataset (Heart Rhythm, 2026). About 1.4 million matched patients. AFib was associated with roughly three times the cancer risk at age 30 to 50, 1.8 times at 50 to 70, and 1.5 times at 70 to 85. The younger the AFib patient, the bigger the excess risk.

A 2020 meta-analysis pooling 533,514 participants put the overall relative risk at 1.24, with lung cancer the most consistent signal.

Isn’t this just more scans finding more cancer?

Partly, in the first 90 days. A new AFib diagnosis means bloodwork, imaging and a closer look, and some cancers get found that way. But the Women’s Health Study risk persisted beyond a year, and the Taiwanese cohort was still elevated past ten years. Detection bias does not run for a decade.

What I do about AFib now: I find the root causes

I treat an AFib diagnosis as a warning light. The rhythm is the symptom. The inflammation underneath it is the disease, and it does not stay in the heart. So in a consultation I look for what is driving it:

• Fasting insulin, HbA1c, triglyceride-to-HDL ratio
• hs-CRP, homocysteine, uric acid, ferritin
• Urine MDA or 8-OHdG as a direct read of oxidative stress
• A sleep study if there is any snoring, daytime fatigue or nighttime AFib
• Omega-3 index, vitamin D, RBC magnesium, B12, folate
• Stool testing for dysbiosis and intestinal permeability
• A dental exam for periodontal disease
• Mold, heavy metal and environmental toxin screens when the history points there

Then the work is on the findings: a diet that lowers insulin, treating the apnea, removing the alcohol, fixing the gut and the gums, getting the toxins out, sleeping. Those are the levers that lower inflammation and oxidative stress, and they lower AFib burden and cancer risk at the same time.

Frequently asked questions

Does AFib cause cancer?
No. The data show an association, not causation. Both conditions share upstream drivers, chiefly chronic inflammation and oxidative stress.

How much higher is cancer risk with AFib?
Roughly 20 to 50% in large cohorts, and close to threefold in people diagnosed with AFib before age 50.

Which cancers are most linked to AFib?
Lung cancer most consistently; colorectal cancer in men in the Danish cohort.

Does AFib ablation lower cancer risk?
There is no evidence that it does. Ablation treats the rhythm, not the inflammatory process behind it.

What should an AFib patient check?
Markers of insulin resistance, inflammation, oxidative stress, sleep apnea, gut health, periodontal disease and environmental toxin exposure.

Sources

• Conen D, et al. Risk of malignant cancer among women with new-onset atrial fibrillation. JAMA Cardiology 2016. PubMed
• Vinter N, et al. Atrial fibrillation and risk of cancer: a Danish population-based cohort study. JAHA 2018. DOI
• Hung YP, et al. Risk and predictors of subsequent cancers of patients with newly-diagnosed atrial fibrillation: a nationwide population-based study. PubMed
• New-onset atrial fibrillation as a predictor of cancer: insights from a real-world dataset. Heart Rhythm 2026. PubMed
• Zhang M, et al. The association of new-onset atrial fibrillation and risk of cancer: a systematic review and meta-analysis. Cardiol Res Pract 2020. PubMed

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Andrew Rudin, MD is a cardiologist and board-certified cardiac electrophysiologist who takes a natural, root-cause approach to heart health. He sees telehealth patients nationally and internationally through Natural Heart Doctor, and is licensed in Tennessee. He has been quoted as an expert source by Medscape and Men’s Journal, and was profiled in The Village Voice. More at andrewrudinmd.com.

This article is for general education and is not medical advice. It is not a substitute for care from your own physician, and nothing here should be used to start, stop, or change treatment on your own.