Association between remnant cholesterol and cardiac conduction block: A prospective cohort study

Background Elevated remnant cholesterol (RC) is recognized as a risk factor for atherosclerotic cardiovascular disease. However, its association with cardiac conduction block (CCB) remains unclear. Objective This study aimed to investigate the relationship between serially measured RC levels and incident CCB. Methods This study used data from the Kailuan study. RC level was measured at baseline in 2006 and at biennial follow-up visits. Cumulative average RC levels were calculated using all available RC measurements before incident cases of CCB or the end of follow-up (December 31, 2019). Cox proportional hazards regression and restricted cubic splines were applied to assess the associations. Results A total of 80,853 participants (78.12% men; mean age 51.55 ± 12.53 years) were included. During a median follow-up of 10.40 years, 3203 incident CCB cases were identified. A U-shaped association was observed between cumulative average RC levels and the risk of CCB (P nonlinearity =.001). Compared with participants with RC levels of 0.76-1.05 mmol/L, the multivariable-adjusted hazard ratios for CCB were 1.55 (95% confidence interval 1.39-1.72) for RC of <0.76 mmol/L and 1.78 (95% confidence interval 1.61-1.97) for RC of ≥1.40 mmol/L. These findings remained consistent across multiple sensitivity analyses. Similar U-shaped associations were observed for the major subtypes of CCB, including atrioventricular block, left bundle branch block, and right bundle branch block. Conclusion Both low and high cumulative average RC levels were associated with an increased risk of CCB and its major subtypes, suggesting the importance of maintaining RC within an optimal range.