Estimating the impact of heat exposure on mortality in New Brunswick

Abstract

In a changing climate, increasing extreme heat events and heatwaves are expected to have profound health impacts, particularly among vulnerable Canadian communities. This study investigates the association between heat, heatwaves, and all-cause mortality, and the modifying effects of area-level socioeconomic factors in New Brunswick from May to September (2007–2021). A Poisson regression model combined with a distributed lag nonlinear model (DLNM) was used to assess cumulative and lagged effects of temperature and heatwaves. Results indicate that extreme temperatures (humidex ≥35) were associated with a 4.1% increase in mortality. Heatwaves lasting two or more consecutive days showed a relative risk (RR) of 1.10, increasing to 1.16 for heatwaves of three or more days. Stratified analysis revealed a 17.3% increased risk of mortality in economically disadvantaged regions and a 15% increased risk in areas with greater ethnocultural diversity. These findings emphasize the need for targeted public health interventions in socioeconomically vulnerable areas.