High testosterone levels are associated with an increased risk of developing atrial fibrillation in older men

Addressing cardiovascular problems in older adults is a critical area of public health. Atrial fibrillation (AFib) is a common and problematic heart rhythm disorder, and researchers are interested in understanding its risk factors.

The study, published in eClinicalMedicine, examined the relationship between testosterone levels and AFib in more than 4,500 men. The researchers found that older men with higher levels of circulating testosterone had an increased risk of AFib. The results highlight the importance of close monitoring of AFib and testosterone levels in older men.

As research progresses, clinicians may need to consider the risks of AFib when assessing the risks of testosterone therapy in older men.

Atrial fibrillation: dangers and risk factors

Atrial fibrillation occurs when the upper chambers of the heart beat irregularly. AFib is the most common type of heart rhythm disorder, according to the Centers for Disease Control and Prevention (CDC). The CDC also estimates that by 2030 there will be 12.1 million people with AFib in the US.

AFib can be dangerous because it increases the risk of blood clots, which can lead to strokes in the brain.

Non-study author Kevin Rabiy, MD, a cardiologist at Memorial Herman, explained:

“Atrial fibrillation is a heart rhythm disorder that causes chaotic electrical activity and contractions in the upper chambers of the heart (atria). This can lead to unpleasant symptoms, but it also increases the risk of stroke and weakens the heart. This is a condition that needs to be carefully monitored and treated by a cardiologist."

Although doctors can help treat AFib with certain medications and even surgery, it is also important to consider how to reduce the risk of AFib. A few common risk factors for AFib include aging, a family history of AFib, panic disorders, excessive alcohol consumption, and smoking.

How does testosterone level affect the risk of AFib?

Researchers of the current study wanted to examine how testosterone levels in older men affect the risk of AFib. They noted that circulating testosterone levels generally decline with age, and that testosterone therapy has increased in older men.

Non-study author Mehran Movassaghi, MD, a board-certified urologist and director of Men's Health at Providence Saint John's Medical Center and assistant professor of urology at Saint John's Cancer Institute in Santa Monica, California, explained:

“As patients age, testosterone levels drop. Starting at age 30, testosterone levels decline by one percent each year. Some patients who start out relatively high may never notice changes in their energy, mood, or sexual performance. However, patients usually complain of symptoms starting around age 40, and at this age it is advisable to have their levels checked. It's important not just to treat the number, but to actually treat the symptoms that patients experience."

The researchers used data from the ASPirin in Reducing Events in the Elderly (ASPREE) study. The study included 4570 healthy men. All participants were over seventy years of age and had no previous history of cardiovascular disease or thyroid cancer. About 12% of participants had diabetes, and 75.9% had a history of hypertension.

The average follow-up time was 4.4 years. During follow-up, 286 men, or 6.2%, developed atrial fibrillation (AFib). The researchers were able to track participants through annual in-person visits and telephone calls every six months.

The researchers divided serum testosterone levels into quintiles and examined how participants' testosterone levels were associated with the incidence of atrial fibrillation.

The study results showed a non-linear relationship between testosterone levels and the incidence of AFib. They found that men with testosterone levels in the highest quintiles had a higher risk of developing AFib than those with more average testosterone levels. Similar results were obtained after excluding participants who experienced heart failure or other major adverse cardiovascular events during follow-up.

The association was also found to be independent of several factors, including body mass index, alcohol consumption, diabetes and high blood pressure.

Study author Cammy Tran, BSci, MPH from Monash University, noted the following:

“We studied 4,570 initially healthy older men aged 70 years and older and found that men with higher testosterone concentrations had nearly twice the risk of developing atrial fibrillation over 4 years of follow-up compared with men whose testosterone concentrations were in the middle range. It was interesting that the higher risk was for men whose testosterone concentrations were within the normal range."