Differential impact of neighbourhood-level income on the risk of cardiovascular event between immigrants and long-term residents in ontario

Cardiovascular disease is a leading cause of death and disability globally. Differences in the incidence of cardiovascular disease due to socioeconomic status are known, but it is unclear if these differences vary by immigration status. Intersectionality theory suggests that immigration status and neighbourhood-level income could interact synergistically, potentially leading to differences in cardiovascular disease between immigrants and long-term residents based on their neighbourhood-level income. Immigrants of diverse ethnicities represent 22% of the Canadian population. Using a population-based cohort in Ontario, Canada, we evaluated whether the association between neighbourhood-level income and the cardiovascular disease incidence varied by immigration status. We used administrative databases to identify community-dwelling adults (aged ≥ 40 years) without prior cardiovascular disease residing in Ontario on January 1, 2011. We obtained immigration status from immigration records and assigned neighbourhood-level income based on census data. We ascertained incidence of cardiovascular (CV) events between 2011 and 2018, defined as hospitalization for stroke (ischemic stroke event or intracerebral hemorrhage) or myocardial infarction or death from cardiovascular disease. We reported baseline differences in vascular risk factors between different neighbourhood-level income quintile, stratified by immigration status. We reported unadjusted rates of CV events for each income quintile and compared these between immigrants and long-term residents. We will use multivariable Cox proportional hazard models to evaluate the interaction between neighbourhood-level income and immigration status. Our study population included 5.3 million adults (19% immigrants). A larger proportion of immigrants lived in the lowest neighbourhood-level income quintile compared to long-term residents (26% vs. 16%) (Figure 1a). Residents of low-income neighbourhoods had a higher burden of vascular risk factors, regardless of immigration status (Table 1 and Figure 1). Immigrants had an overall lower rate of CV events compared to long-term residents (2.9 vs. 5.1 per 1000 person-years); lower income neighbourhood was associated with a higher rate of CV events in immigrants (Q1 vs. Q5, 3.4 vs. 2.2; rate ratio 1.5) and long-term residents (6.5 vs. 4.2; rate ratio 1.5); and the decline in CV rate with higher income was less pronounced among immigrants than long-term residents (Table 1 and Figure 1). CV event rates were higher among immigrants and long-term residents residing in low-income neighbourhoods compared to high-income neighbourhoods, with a potentially smaller influence of neighbourhood-level income among immigrants. Future work should evaluate the reasons for the differential effect of income on CV events among immigrants and long-term residents.View Large Image Figure ViewerDownload Hi-res image Download (PPT)