AFib in Overweight Individuals May Not Be Related to Fat, New Analysis Suggests

New study results in Trends in Cardiovascular Medicine indicate that atrial fibrillation (AFib) in people who are overweight is not linked to the amount of body fat.

The research team, from Aarhus University in Denmark, conducted a review of literature looking at body fat and fat-free mass in the risk of survival for AFib, and produced a meta-analysis summarizing the relevant studies. Among the research was a study the authors were also conducting in more than 56,000 participants in the Danish Diet Cancer and Health project (study title: Lean Body Mass Is the Predominant Anthropometric Risk Factor for Atrial Fibrillation)

“While it’s correct that overweight individuals have a clearly elevated risk of atrial fibrillation, there is no clear evidence that fat is of any significance when we adjust for these individuals’ high fat-free mass,” explained senior researcher  Research Unit for General Practice at Aarhus and study author Dr. Morten Fenger-Grøn, in a press release. “Conversely, it appears that people with high fat-free weight do have a high risk, regardless of whether they have a lot of fat on their body or not.”

It had been previously thought that being overweight was associated with an increased risk for AFib. The current analysis revealed that the risk for AFib may not be linked to the amount of adipose tissue, but rather fat-free weight. Large individuals, the authors noted in their study, are at an increased risk for AFib due to increased height and weight. While obese individuals are also at increased risk, their risk also stems from other comorbidities often related to obesity.

“Mounting evidence suggests that AFib risk is closely associated with a high lean body (fat-free) mass, whereas evidence for an independent influence of the mass of fat tissue is sparse, particularly if we disregard the impact of fat on the risk of developing other cardiovascular conditions that may promote AFib,” the authors wrote in the conclusion. “Nevertheless, weight loss or weight limiting still seems recommendable in order to lower AFib risk, but further investigations are needed to explore how to frame future weight reduction interventions, especially because endurance exercise is known to constitute an independent AFib risk factor.”

Dr. Fenger-Gron added: “Our results point to the importance of remembering to also look for this condition in people who are muscular and without overwhelming body fat – even though they appear to be very healthy and robust.”