Predicting high-resolution spatial and temporal variations in summer air temperatures and its effect on asthma and myocardial-infarctions in Montreal, Canada

Abstract

BACKGROUND AND AIM: To develop and apply new high-resolution models of within-city spatiotemporal variations in summer air temperatures in Montreal, Canada and evaluate associations with emergency room visits for asthma and myocardial. METHODS: We developed a new model to predict temperatures across Montreal using a large database of temperature measurements collected from 200 sites across Montreal during the summers of 2018 and 2019. Using these data, we conducted a case crossover study of daily temperature and emergency room visits for asthmas and myocardial infractions between 2014-2018. Conditional logistic regression models were analyzed using traditional fixed-site monitors and our new high-resolution models. RESULTS:There was a positive association between daily mean temperature and myocardial infraction using both fixed-site temperature data [OR=1.076 (95% CI: 1.0081-1.149) per 5oC] as well as our new high-resolution model [OR = 1.077 (95% CI: 1.0098-1.148) per 5oC]. Among older women, temperature was more strongly associated with myocardial infarction using our new high-resolution mode (OR = 1.147 (95% CI: 1.0057, 1.309) per 5oC] compared to fixed-site measurements [OR = 1.104 (95% CI: 0.9963, 1.304) per 5oC]. There was a negative association in individuals below the median age of 57 who had asthma using the fixed temperature site [OR = 0.7001 (95% CI: 0.5315-0.9222) per 5oC] as well as the high-resolution model [OR = 0.7423 (95% CI: 0.5710-0.9649) per 5oC]. CONCLUSIONS:Daily variations in summer temperatures are positively associated with acute myocardial infarction. Stronger associations were generally observed using our new high-resolution estimates of spatio-temporal variations in temperature compared to traditional fixed site measurements. KEYWORDS: Asthma, myocardial infractions, case-crossover study, heatwaves, extreme temperatures