Adults with atrial fibrillation have an increased prevalence of cardiovascular risk factors such as stroke, MI and heart failure years before they are diagnosed with the condition, according to an analysis of a large, community-based cohort.

Lead researcher Faye L. Norby, MS, MPH, of the University of Minnesota, and colleagues published their results online in Circulation on Aug. 22.

The researchers mentioned that 25 percent of people have atrial fibrillation during their lifetimes and that the prevalence increases as people get older. Risk factors include age, white race, obesity, smoking, hypertension, diabetes and a history of MI and heart failure.

They examined the trajectories of cardiovascular risk factors in 2,456 adults with atrial fibrillation who enrolled in the ARIC (Atherosclerosis Risk in Communities) study. They also assessed 6,414 matching controls who did not have atrial fibrillation.

Participants in the ARIC study were between 45 and 64 years old at baseline and enrolled between 1987 and 1989 in Washington County, Maryland; the northwest suburbs of Minneapolis; Jackson, Mississippi; and Forsyth County, North Carolina. After their initial assessments, the adults were examined four other times and received annual follow-up calls.

During a median follow-up period of 24 years, the researchers detected 2,456 cases of atrial fibrillation. People with atrial fibrillation had higher body mass index and a greater prevalence of current smoking, hypertension, diabetes, heart failure, MI and stroke.

Participants with atrial fibrillation had a higher prevalence of most cardiovascular risk factors even 15 years before diagnosis, including a significantly higher prevalence of obesity, smoking and heart failure. The researchers also found diverse trajectories in the prevalence of risk factors and cardiovascular outcomes.

They added that there were steep increases in the prevalence of stroke, MI and heart failure before the diagnosis of atrial fibrillation. The prevalence of hypertension and diabetes had monotonic increases over time, while the prevalence of smoking and obesity decreased in prevalence after participants were diagnosed with atrial fibrillation. 

Further, they noted that participants with high blood pressure and those who have been obese for a long time have the highest risk of atrial fibrillation.

“These results underscore the role of factors such as hypertension and obesity in contributing to the development of the atrial substrate that eventually leads to the clinical onset of [atrial fibrillation] and the need to act earlier in the pathogenic process to prevent this common arrhythmia,” the researchers wrote.

The researchers mentioned a few potential limitations of the study, including that they might have misclassified the diagnosis of heart failure and atrial fibrillation. They also did not capture outpatient atrial fibrillation cases. In addition, they mentioned that the study could have been subject to selection bias because adults who lived longer may have had a healthier cardiovascular profile compared with those who died shortly after being diagnosed with atrial fibrillation.

“Exploring the timing and trajectories of risk factor development in relation to [atrial fibrillation] diagnosis could provide insights into the pathogenesis of this common arrhythmia and inform prevention strategies,” the researchers wrote. “This large community-based study with 25 years of follow-up demonstrated an increased prevalence of cardiovascular risk factors in [atrial fibrillation] patients many years before disease diagnosis and identified diverse trajectories in the prevalence of these risk factors, highlighting their different roles in [atrial fibrillation] pathogenesis and the need to establish preventive strategies that address risk factors decades before [atrial fibrillation] diagnosis.”