Presidential candidates Joe Biden and Michael Bloomberg have released doctors’ letters saying that they have atrial fibrillation (AF), an irregular heartbeat that quintuples risk for stroke and doubles it for heart attack and dementia. Both men are 77, take heart medications and are being treated for several medical conditions, but they have been pronounced healthy and fit for office by their medical providers.

Rates of AF have quadrupled in the U.S. over the past 50 years — and the disorder was recently described as a “global epidemic” in the American Heart Association’s journal Circulation. Yet this heart arrhythmia is potentially preventable, often with simple lifestyle changes. Here’s a look at the latest research and a new blood test that checks for a genetic variant that greatly increases your risk of developing this serious, but treatable, disorder.

How does AF affect the heart?

AF is the most common type of heart arrhythmia, affecting up to 6.1 million Americans. It occurs when the heart’s two upper chambers (the atria) develop chaotic electrical signals. This causes the atria to squeeze very quickly in a disorganized rhythm and get out of sync with the two lower chambers (the ventricles).

AF causes blood to pool in the heart, which may cause blood clots. If a clot travels to an artery in the brain, a stroke can result. Up to 20 percent of strokes occur in people with AF. Similarly, if a clot obstructs one of the arteries that supply the heart, the result can be a heart attack. People with AF are also at increased risk for heart failure, dementia and sudden cardiac death, particularly if their disorder goes undiagnosed and untreated.

Who is at risk for AF?

AF is most common in older adults — and the aging of the population is one of the main reasons why rates of this disorder are on the rise. It’s also more likely to strike people who have cardiovascular disease (CVD). For example, Bloomberg, the former mayor of New York City, has CVD that was treated in 2000 with the placement of two stents to prop open obstructed heart arteries, according to his doctor’s report.

Genes also play a role. People with a genetic variant called 4q25 have a 140 percent higher risk for AF and 130 percent high risk for strokes caused by blood clots originating in the heart (cardiothrombotic stroke), compared to noncarriers of this gene. About one in three people carry the 4q25 genetic variant. The gene can be detected with a simple blood test, available at medical labs all over the U.S. if ordered by a medical provider.

Who should get the 4Q25 genetic test?

Based on the recent studies, the BaleDoneen Method recommends the test for people with any of the following red flags for increased risk of developing AF:

  • Diabetes
  • Cardiovascular disease
  • Obesity and/or poor cardiovascular fitness
  • A resting heart rate above 84 beats per minute
  • Obstructive sleep apnea
  • High blood pressure
  • Chronic obstructive pulmonary disease (COPD)
  • Rheumatoid arthritis
  • Low levels of magnesium and/or potassium
  • Thyroid disorders
  • Kidney disease
  • A family history of AF
  • Use of alendronate (an osteoporosis medication sold under such brand names as Fosamax and Binosto)
  • Having an ischemic (clot-caused) stroke, particularly if the cause was unclear
  • Advanced age (AF is most common in people ages 65 and older)

What can you do to lower your risk for developing AF?

The same strategies that help keep your heart healthy can also cut your risk for AF, such as exercising regularly, maintaining a healthy weight, avoiding nicotine use or exposure and eating a heart-healthy diet. Recent studies also reveal other simple strategies to keep AF at bay:

  • If your blood pressure is high, work with your medical provider to lower it. Reducing your systolic blood pressure (the top number) to less than 130 mmHG cuts risk for AF by 30 percent, compared to pressure above 142. For people at particularly high risk for AF, medication may be advised, along with lifestyle improvement.
  • Eat foods that are high in Omega-3 fatty acids. In a recent study, people with the highest levels of Omega-3 in their blood had a 39 percent lower rate of AF, compared to peers with the lowest levels. Omega-3 fatty acids are found in oily fish (such as salmon, tuna, lake trout, sardines and herring), nuts, flax seeds, vegetable oils and leafy green vegetables. If your Omega-3 levels are low, ask your medical provider if a supplement is right for you.
  • Use extra-virgin olive oil. In a recent study of adults age 55 and older, those who ate a Mediterranean diet that included 50 grams (about 4 teaspoons) of extra-virgin olive oil daily had a 38 percent lower risk for AF, compared to a control group. The BaleDoneen Method recommends a diet based on your DNA as one of the best ways to protect your heart and brain health.
  • Drink coffee. Most studies report that drinking two to three cups daily is safe and either neutral or beneficial in protecting against AF and stroke. Coffee consumption is also linked to lower risk for diabetes, high blood pressure, obesity and depression. However, some people carry a variant of the CYP1A2 gene that makes them metabolize caffeine slowly. In this group, coffee may be harmful to heart health. For example, a study of moderate and heavy drinkers of coffee found that the slow metabolizers were much more likely to develop high blood pressure than rapid metabolizers.