Influence of abdominal obesity and habitual behaviors on incident atrial fibrillation in Japanese

•Abdominal-obesity, smoking, alcohol intake, physical activity, and atrial fibrillation (AF) were examined.•Abdominal-obesity was the independent risk factor of incident AF in Japanese.•Abdominal-obesity without or with overweight also elevated the risk of incident AF.•Excess alcohol intake in males significantly elevated the risk of incident AF.•Incident AF was about 3 times higher in aggregation of four modifiable factors. As atrial fibrillation (AF) increases with the aging of the population, it is urgently required to clarify modifiable factors to prevent AF. However, evidence regarding the independent influence of abdominal-obesity and habitual behaviors on incident AF is limited among Japanese. Those aged 40–79 years undergoing periodic health checkups during 2008–2014 were followed-up in 2015 (n=96,841) and the independent risk of incident AF was estimated using multivariate Cox proportional hazards regression models after adjustment for potential covariates. Participants were classified into four groups according to the baseline body mass index (BMI: kg/m2) (normal-BMI or overweight: < or ≥25) and waist circumference (WC: cm) (normal-WC or abdominal-obesity: < or ≥85 for male, ≥90 for female). Baseline habitual behaviors, smoking status, alcohol intake, and physical activity, were also included as modifiable factors. Among 65,984 eligible participants, 349 developed AF over mean follow-up of 5.5±1.6 years. Increase of both BMI and WC significantly elevated the risk of AF. Compared to the normal-BMI and normal-WC group, the normal-BMI but abdominal-obesity and the overweight and abdominal-obesity groups in males and the overweight and abdominal-obesity group in females had significantly elevated risk of AF. Among modifiable behavioral factors including abdominal-obesity, alcohol intake (≥40g/day) and abdominal-obesity significantly elevated the risk of AF in males, and abdominal-obesity was the strongest risk factor in both sexes, but smoking and physical activity were not significant. However, an aggregation of these four behavioral factors increased the risk of AF more than 2.5 times in both sexes. Abdominal-obesity could be a crucial risk factor in prediction of AF in Japanese, and an aggregation of four behavioral factors increased the risk of AF almost three times. To prevent incident AF, practicing healthy habitual behaviors is recommended.