Secondhand tobacco smoke and risk of atrial fibrillation: An observational epidemiologic and gene-environment interaction analysis.

BACKGROUND

The relationship between secondhand tobacco smoke (SHS) and the risk of incident atrial fibrillation (AF) remains controversial.

OBJECTIVE

This study aimed to evaluate the long-term risk of AF associated with SHS exposure and assess potential gene-environment interactions using extensive population-based data.

METHODS

We performed a nationwide population-based cohort study using the UK Biobank database. Participants were categorized into SHS-exposure and nonexposure groups. The primary outcome was the risk of incident AF. We also evaluated the synergistic effect of SHS exposure and the polygenic risk score of AF.

RESULTS

During a median follow-up of 12.5 years, AF occurred in 23,471 (5.9%). The SHS-exposure group (median exposure 0.5 [0.5-1.5] h/wk) was younger and predominantly male. The risk of AF was significantly higher in the SHS-exposure group (multivariable-adjusted hazard ratio 1.06; 95% confidence interval 1.02-1.09; P = .002) than the nonexposure group, suggesting a dose-dependent manner (adjusted hazard ratio of the severe SHS-exposure group 1.11; 1.04-1.18; P = .001). The risk of AF was higher in the SHS-exposure group regardless of the exposure location (home, outside, or workplace). When SHS exposure was combined with the high genetic risk of AF, a significant additive interaction was observed on the risk of AF (synergy index of SHS exposure with the third tertile of AF polygenic risk score 1.13; 1.05-1.21; P = .024).

CONCLUSION

Exposure to SHS is a significant predictor of an increased risk of AF, with a synergistic effect when combined with genetic predisposition. Minimizing SHS exposure, especially in individuals with a heightened genetic susceptibility to AF, may potentially reduce the future risk of AF.