A Common Heart Condition Linked to High Testosterone Levels: New Research

A recent study suggested a correlation between elevated testosterone levels in elderly men and a heightened risk of developing a common cardiac condition called atrial fibrillation that escalates the stroke risk.

This research extends earlier studies identifying a correlation between testosterone levels and atrial fibrillation, or AFib. A recent clinical trial, the Testosterone Replacement Therapy for Assessment of Long-term Vascular Events and Efficacy Response in Hypogonadal Men (TRAVERSE) study, revealed that men with cardiovascular disease risk factors undergoing testosterone-replacement therapy may have an increased AFib risk.

However, this latest research, published in The Lancet, indicates even men with naturally high testosterone levels and no heart disease risk factors may still be at an elevated risk of developing Afib.

According to Cammie Tran, MPH, the lead study author and a researcher at Monash University, even in healthy men aged over 70 years without a prior cardiovascular disease history including AFib, there still exists a risk between elevated testosterone concentrations and Afib. She explained that although the study doesn't establish causation, the findings hint at Afib being a possible negative outcome of higher testosterone concentrations. As a result, she advises clinicians to consider this risk when evaluating testosterone concentrations in older men.

AFib, being the most frequently treated form of irregular heartbeat or arrhythmia, affects around 70% of individuals between the ages of 65 and 85 years, with approximately equal prevalence in men and women. By 2030, the Centers for Disease Control and Prevention anticipates around 12.1 million AFib cases in the United States.

People with Afib experience abnormal heartbeats—either too slow, too fast, or irregular due to improper coordination between the upper and lower chambers of the heart. While some might be asymptomatic, others might exhibit symptoms like chest fluttering, breathlessness, chest pain, or light-headedness. Approximately one in seven strokes are a result of AFib, which can lead to more severe strokes.

Tran's team sought to assess Afib risk in healthy older men not being treated with testosterone.

To explore this link, the researchers compiled data on 4,570 men participating in the ASPREE clinical trial, a long-term study of the effects of aspirin on older adults' health.

These participants, aged 70 years and above, had neither a history of cardiovascular disease, prostate cancer, thyroid disease, dementia, nor other life-threatening illnesses.

The study required the men to provide blood and urine samples at the beginning, and follow-ups were scheduled every six months for about three to five years. Out of the total participants, 286 developed Afib during this period.

After adjusting for factors like age, smoking status, and body mass index, the research team concluded that men diagnosed with Afib had initially higher average testosterone levels—17 nmol/L as compared to 15.7 nmol/L for those who didn't develop Afib. Men with the highest testosterone levels were found to be more susceptible to Afib in comparison to those with mid-range testosterone concentrations.

According to Tran, the risk connecting testosterone and Afib is present in the highest 40% of testosterone concentrations. Therefore, it's not unusual to belong to this risk-prone group.

The correlation between testosterone levels and Afib risk was found to be non-linear, implying that men with testosterone levels below normal also exhibited higher chances of developing Afib.

Tran suggested that maintaining mid-range testosterone concentrations could possibly mitigate the risk of Afib.

This research bolsters the TRAVERSE study's conclusions, according to Steven Nissen, MD, a cardiologist at the Cleveland Clinic and a leading researcher in the study. He stated that a relationship seems to exist between testosterone levels and atrial fibrillation.

Megan Kamath, MD, a cardiologist at UCLA Health, told Health that the study reveals the importance of assessing a patient's total risk for atrial fibrillation considering their age, comorbidities, and other medical conditions when pondering testosterone supplementation. However, she emphasizes the need for more research to gain a deeper understanding of how testosterone levels might affect Afib risk.

Nevertheless, the study faces certain limitations. Tran pointed out that sample collections were not synchronized with the time of day despite knowledge of circadian rhythms influencing testosterone concentration.

Additionally, other sex hormones such as estradiol, free testosterone, dihydrotestosterone (DHT), and sex hormone binding globulin (SHGB) weren’t measured, per Tran, “restricting our ability to consider possible mechanisms” behind testosterone’s potential effect on Afib risk.

So far, research hasn’t uncovered exactly why testosterone might be related to heart health. But Tran suggested several possibilities.

Some evidence shows that people with higher testosterone have shorter telomeres, which research has associated with a higher risk of AFib.

“Other studies suggest that testosterone’s conversion to estradiol relates to expression of genes in fat at the surface of the heart, or that testosterone increases expression of receptors or excitability in heart tissues, predisposing to AF,” she added.

However, “these possibilities need to be examined further,” she said.

People with low testosterone levels might be interested in or prescribed testosterone replacement therapy to raise circulating levels of the hormone.

However, the study authors said that despite its limitations, the research reinforces the need for patients and medical providers to weigh both risks and benefits when considering TRT. 

Sharing an accurate and complete medication list with doctors can help them make this calculation, Kamath emphasized.

If you opt for TRT, she said to pay attention to any new symptoms and share them with a medical professional. People with high testosterone levels may experience a number of symptoms, including: