The Effect of Urban Heat Island Intensity on the Rate of Emergency Department Visits for Acute Myocardial Infarctions

Abstract Aims This study investigates the effect of urban heat island exposure on clinically significant cardiovascular disease (CVD) and how this relationship changes when accounting for other environmental and social factors. Methods We used publicly available data from California urban areas on a census tract-level, including surface urban heat island intensity (SUHII), acute myocardial infarction (AMI) event rate, fine particulate matter pollution (PM2.5), the Normalized Difference Vegetation Index (NDVI), racial and ethnic group percentages, and the Social Vulnerability Index (SVI). We created models to explore how these variables affect the predicted AMI event rate. We created census tract-level bivariate choropleth maps of urban areas in California counties. Results The models predict that residents in urban census tracts with median and high SUHII exposure have a 17% and 22% increased AMI event rate, respectively, compared to residents living in census tracts with low SUHII exposure. Increasing PM2.5 and SVI were associated with increasing predicted AMI event rates. Urban census tracts with a higher percentage of individuals who identify as Hispanic, Black, and American Indian had higher predicted AMI event rates. Conclusion This study highlights the intersection of SUHII, AMI events, and various environmental and social factors within urban areas on a census tract-level. It emphasizes the need to implement mitigation strategies to decrease the UHI effect, which may reduce the rate of heat-related AMI events.