Accelerated ageing plays a mediating role in the associations of socioeconomic position with arrhythmias: evidence from the UK Biobank cohort

The contribution of socioeconomic position (SEP) to arrhythmias remains unclear. We aimed to examine the extent to which accelerated ageing mediates the associations of SEP and atrial fibrillation/flutter (AF), ventricular arrhythmias (VA), and bradyarrhythmias. Data were collected from the UK Biobank. SEP was determined by household income, education level and employment status using latent class analysis. Accelerated ageing was assessed by PhenoAge and BioAge acceleration calculated using nine and seven blood biomarkers respectively. Outcomes were AF, VA and bradyarrhythmia. Counterfactual mediation analysis was used to evaluate the mediation proportion of accelerated ageing in the association of SEP with arrhythmias. A total of 224,389 participants were included in the study. With a median follow-up of 13.33 years, 1,843 (0.82%) VA and 3,657 (1.63%) bradyarrhythmia. The associations of SEP on AF, VA and bradyarrhythmia with HR were 1.24(95% CI: 1.17, 1.30), 1.53(95% CI: 1.32, 1.77), and 1.23(95% CI: 1.11, 1.37), respectively. The indirect effect of lower SEP on arrhythmias risk via PhenoAge was 5% (95% CI: 4%, 5%) higher risk of AF with the mediation proportion of 23.53%, 7% (95% CI: 6%, 8%) higher risk of VA with the mediation proportion of 19.49%, 4% (95% CI: 4%, 5%) higher risk of bradyarrhythmia with the mediation proportion of 21.12%. Stratified analyses showed that the mediation proportion of accelerated ageing on AF was greater in males and in former or current smokers. Lower SEP was associated with higher risks of AF, VA, and bradyarrhythmia, with accelerated ageing statistically accounting for approximately 20% of these associations.