A landmark study has revealed that decades of elite rowing combined with genetic predisposition can significantly elevate the risk of arrhythmia, underscoring that not all heart risks in athletes are equal. This research, published in the European Heart Journal, delves into the prevalence of atrial fibrillation (AF) among former world-class rowers, exploring the roles of both environmental and genetic factors.
The study, titled “Atrial Fibrillation in Former World-Class Rowers: Role of Environmental and Genetic Factors,” investigates how genetic predisposition and the physical demands of elite sports contribute to AF. The findings are particularly relevant as they challenge the conventional wisdom that athleticism universally equates to heart health.
Atrial Fibrillation in Athletes: A Closer Look
Atrial fibrillation is a heart rhythm disorder that heightens the risk of stroke and heart failure. While common risk factors include hypertension, obstructive sleep apnea, and obesity, endurance athletes have been found to face a higher risk of developing AF compared to non-athletes. The reasons behind this increased susceptibility remain complex and multifaceted.
Several hypotheses have been proposed to explain this phenomenon. Among them are inflammation, exercise-induced hemodynamic stretch, and intercurrent illnesses. The study highlights cardiac remodeling, a structural and electrophysiological adaptation from years of intense training, as a key factor in the elevated risk of AF among athletes.
Genetic Factors and Athletic Training
Previous research has suggested that athletic training might activate genes that contribute to AF development. Notably, truncating variants in the TTN gene have been associated with early onset AF. This genetic predisposition explains why some younger athletes develop AF despite lacking other risk factors. However, more research is needed to fully understand the genetic mechanisms at play.
Observational studies have indicated that athletes with longer careers in professional settings are at an increased risk of AF, even years after retiring from competition. The long-term consequences of high-level athletic participation are becoming increasingly apparent, with risks persisting decades after athletes leave the sport.
The ProAFHeart Study: Methodology and Findings
The ProAFHeart study aimed to estimate AF prevalence among elite retired rowers and assess the role of genetic predisposition. Participants included former elite rowers who competed at national, world championship, or Olympic levels between 1960 and 1992. These individuals, aged 45 to 80, were identified from Australian Rowing History and compared to a control group from the UK Biobank.
The study’s findings were striking. Compared to the control group, retired athletes engaged in more exercise, were leaner, taller, and had greater bone mineral density. However, they also exhibited a significantly higher prevalence of AF. Over a four-year follow-up period, athletes were 2.8 times more likely to develop AF than their non-athletic counterparts.
“AF prevalence was significantly higher among retired athletes (27.5%) than lifelong athletes (9.8%), highlighting the long-term impact of elite sports on heart health.”
Genetic Analysis and Risk Factors
Genetic analysis revealed that athletes with a high polygenic risk score (PRS) were nearly four times more likely to develop AF compared to those with lower scores. Interestingly, the proportion of individuals with high polygenic risk was similar in both the athlete and control groups, suggesting that while genetic factors play a role, they do not fully account for the higher AF prevalence in athletes.
The study also explored the presence of pathogenic variants in cardiomyopathy genes, finding a low overall yield. Only one athlete with a JUP variant had AF, while others with different variants did not. This indicates that background genetic variation may be more pertinent to predicting AF risks than specific inherited cardiomyopathies.
Implications and Future Directions
The findings of the ProAFHeart study have significant implications for understanding heart health in athletes. The persistence of cardiac remodeling long after retirement suggests that the effects of elite sports on the heart are enduring. This underscores the importance of monitoring heart health in retired athletes and considering genetic factors in risk assessments.
Future research should focus on a more diverse and inclusive athletic population, particularly among women, to better understand the interplay between genetics and athletic training. The potential use of polygenic risk scores for risk stratification and screening policies among athletes could offer new avenues for early intervention and prevention.
As the sports community continues to grapple with the complex relationship between athleticism and heart health, studies like ProAFHeart provide crucial insights into the unique challenges faced by elite athletes. Understanding these risks is essential for developing targeted strategies to protect the heart health of current and former athletes alike.
