The role of life's essential 8 and multimorbidity in the risk of new-onset atrial fibrillation: observations from a large prospective cohort study.

Background: The risk of atrial fibrillation (AF) is accentuated by age and comorbidities. Healthy lifestyle behaviours, based on Life's Essential 8 (LE8), may modify the risk of new-onset AF mitigating the impact of multimorbidity. The aim of this study was to investigate the associations of LE8 with multimorbidity status, linked to AF incidence.

Methods: A total of 255,280 participants free of AF were included. LE8 was assessed using 8 metrics and categorized into low, moderate, and high cardiovascular health (CVH). Multimorbidity clusters were determined using latent class analysis using 36 long-term conditions (LTCs), categorized into five groups as follows: 3 multimorbidity clusters (non-cardiovascular disease (non-CVD); mental health; and cardio-metabolic multimorbidity); no LTCs; and singular LTCs. The relationships of LE8 and multimorbidity status with AF incidence were evaluated using Cox models and counterfactual analyses.

Results: During an average follow-up of 11.7 years (SD 2.2), 15,069 participants without AF at baseline (mean age 56.2; SD 8.1; 51.9% female and 48.1% male) developed AF. Individuals with high CVH had a 27% lower risk of AF than those with low CVH. Compared to individuals without multimorbidity, participants with singular LTC or multimorbidity clusters had higher AF risk. Up to 54.7% of the associations between multimorbidity status and AF were mediated by LE8. Counterfactual analysis showed increasing the LE8 score to 80 could reduce AF occurrence in multimorbidity individuals by 22.12% to 24.56%.

Conclusion: Lower LE8 scores and multimorbidity were associated with higher AF incidence. Adherence to healthy lifestyle, based on LE8 may prevent AF, especially in those with multimorbidity.