Association between cumulative low-income status and cardiovascular event incidence and mediating effect of engagement in health behaviour: a retrospective cohort study

Abstract

Aims Income influences individuals' engagement in health behaviours, which may mediate the relationship between income and cardiovascular event incidence. However, research on the association between cardiovascular event and cumulative low-income status remains limited, as most previous studies have assessed income at a single time point. This study aimed to investigate the association between cumulative low-income status and cardiovascular event incidence and to explore the mediating role of engagement in health behaviour.Methods and results In this retrospective cohort study, we analysed national representative data from the Korea Health Panel Survey (2008-2018), including 9284 Korean adults. Cumulative low-income status was defined based on total number of years classified as low-income status during the 3 year baseline. Cardiovascular event incidence was defined as the first diagnosis of myocardial infarction, stroke, or cardiovascular disease-related death. Engagement in health behaviour was measured through smoking, alcohol consumption, and physical activity. After adjusting for covariates, Cox proportional hazard models showed an association between increased risk of cardiovascular event incidence and prolonged cumulative low-income status [1 or 2 years: hazard ratio (HR) = 1.27, 95% confidence interval (CI) = 0.97-1.67; 3 years: HR = 1.33, 95% CI = 1.01-1.77; P for trend = 0.045]. A generalized structural equation model revealed that engagement in negative health behaviour mediated the longitudinal relationship between 1 and 2 years of cumulative low-income status and cardiovascular event incidence (indirect effect estimate = 0.179, P-value = 0.004).Conclusion These findings suggest that interventions targeting engagement in health behaviour among population with cumulative low-income status may help prevent cardiovascular events and promote cardiovascular health equity.