Chronic Diseases Associated With Mortality in British Columbia, Canada During the 2021 Western North America Extreme Heat Event. (15th March 2023)

• Record Type: Journal Article
• Authors: Lee, Michael Joseph; McLean, Kathleen E.; Kuo, Michael; Richardson, Gregory R. A.; Henderson, Sarah B.
• Is Part Of: GeoHealth. Volume 7:Number 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-15
• Subjects: extreme heat -- mortality -- chronic disease -- vital statistics -- administrative data -- air quality; Environmental health -- Periodicals; Electronic journals; Periodicals; 616.98
• DOI: 10.1029/2022GH000729
• Languages: English
• ISSNs: 2471-1403

Abstract

Abstract: Western North America experienced an unprecedented extreme heat event (EHE) in 2021, characterized by high temperatures and reduced air quality. There were approximately 740 excess deaths during the EHE in the province of British Columbia, making it one of the deadliest weather events in Canadian history. It is important to understand who is at risk of death during EHEs so that appropriate public health interventions can be developed. This study compares 1, 614 deaths from 25 June to 02 July 2021 with 6, 524 deaths on the same dates from 2012 to 2020 to examine differences in the prevalence of 26 chronic diseases between the two groups. Conditional logistic regression was used to estimate the odds ratio (OR) for each chronic disease, adjusted for age, sex, and all other diseases, and conditioned on geographic area. The OR [95% confidence interval] for schizophrenia among all EHE deaths was 3.07 [2.39, 3.94], and was larger than the ORs for other conditions. Chronic kidney disease and ischemic heart disease were also significantly increased among all EHE deaths, with ORs of 1.36 [1.18, 1.56] and 1.18 [1.00, 1.38], respectively. Chronic diseases associated with EHE mortality were somewhat different for deaths attributed to extreme heat, deaths with an unknown/pending cause, and non‐heat‐related deaths. Schizophrenia was the only condition associated with significantly increased odds of EHE mortality in all three subgroups. These results confirm the role of mental illness in EHE risk and provide further impetus for interventions that target specific groups of high‐risk individuals based on underlying chronic conditions. Plain Language Summary: Western North America experienced the most severe extreme heat event (EHE) ever recorded in the region during the summer of 2021. There were approximately 740 more deaths than usual in British Columbia, Canada during the EHE, which made it one of the deadliest weather events in Canadian history. This study compares people who died during the EHE with people who died at the same time of year in other years to identify differences between the two groups with respect to 26 chronic diseases. We found that people with schizophrenia were at much higher risk than others during the EHE. People with chronic kidney disease and ischemic heart disease were also at increased risk. This information will be used to help develop programs that support people at higher risk during future EHEs. Key Points: British Columbia experienced an unprecedented extreme heat event (EHE) in summer 2021 associated with a 95% increase in population mortality Deaths during the EHE and previous years were compared with respect to chronic diseases present at time of death Schizophrenia was most strongly associated with higher risk of death during the EHE