Association between air temperature and COVID-19 emergency department visits in Ontario, Canada: A population-based case-crossover study

IF 4.3 2区医学 Q1 INFECTIOUS DISEASES

International journal of hygiene and environmental health Pub Date : 2026-07-01 Epub Date: 2026-07-07 DOI:10.1016/j.ijheh.2026.114856

Nicholas Grubic, Erjia Ge, Zhou Zang, Eric Lavigne, Michael A. Campitelli, Haley Golding, Tariq Cisse, Maria Koh, Brice Batomen, Jane Liu, Xiaolin Wei

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引用次数: 0

Abstract

Background

The impact of air temperature on COVID-19-related health outcomes, particularly in the context of extreme weather, remains underexplored.

Methods

This time-stratified case-crossover study included 200,679 laboratory-confirmed COVID-19 emergency department (ED) visits in Ontario, Canada, from 2020 to 2023. Conditional logistic regression with distributed lag nonlinear models was used to assess the association of mean daily temperature with COVID-19 ED visits. Cumulative 0-5-day lag associations of cold and heat exposure were presented as odds ratios (ORs) with 95% confidence intervals (CIs) at the 1st and 99th percentiles of the temperature distribution, referenced to the minimum risk temperature (MRT).

Results

A non-linear, W-shaped relationship was observed between temperature and COVID-19 ED visits, with associations in extreme to very cold (−35.7°C to −21.6°C), cold (−14.1°C to −10.3°C), lightly cold to moderate (−10.2°C to 21.6°C), and warm to very hot (21.7°C to 29.2°C) temperature ranges (MRT: −17.2°C). Notably, heat exposure (24.6°C) showed stronger associations (OR: 1.53, 95% CI: 1.40-1.67) than cold exposure (−17.6°C, OR: 1.00, 95% CI: 0.996-1.005). Risk patterns varied across viral variants, with cold exposure associated with increased ED visits for Omicron and Wild variants, while heat exposure was linked to increased visits for Alpha, Delta, and Gamma variants. Associations were more pronounced for females, individuals aged <65 years, and those with a primary COVID-19 diagnosis.

Conclusion

Short-term exposure to non-optimal temperatures significantly increases COVID-19-related emergency healthcare demand, with variant- and demographic-specific differences. Temperature-responsive public health strategies are needed to reduce the burden of COVID-19 and other infectious diseases as climate extremes intensify.

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加拿大安大略省气温与COVID-19急诊就诊之间的关系：一项基于人群的病例交叉研究

背景：气温对与covid -19相关的健康结果的影响，特别是在极端天气的背景下，仍未得到充分探讨。方法：这项时间分层的病例交叉研究包括加拿大安大略省2020年至2023年200,679例实验室确诊的COVID-19急诊科就诊病例。采用分布滞后非线性模型的条件logistic回归评估平均日气温与COVID-19急诊科就诊的关系。参考最低风险温度（MRT），以温度分布的第1和第99百分位数的95%置信区间（ci）的比值比（or）表示冷暴露和热暴露的累积0-5天滞后关联。结果：在温度与COVID-19 ED就诊之间观察到非线性的w形关系，与极端到极冷（-35.7°C至-21.6°C）、寒冷（-14.1°C至-10.3°C）、轻度冷到中度（-10.2°C至21.6°C）以及温暖到非常热（21.7°C至29.2°C）的温度范围（MRT: -17.2°C）相关。值得注意的是，热暴露（24.6°C）比冷暴露（-17.6°C, OR: 1.00, 95% CI: 0.996-1.005）显示出更强的相关性（OR: 1.53, 95% CI: 1.40-1.67）。不同病毒变体的风险模式各不相同，冷暴露与Omicron和Wild变体的ED就诊次数增加有关，而热暴露与Alpha， Delta和Gamma变体的ED就诊次数增加有关。结论：短期暴露于非最佳温度会显著增加与covid -19相关的紧急医疗需求，并存在变异和人口统计学差异。随着极端气候加剧，需要采取温度响应型公共卫生战略，以减轻COVID-19和其他传染病的负担。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International journal of hygiene and environmental health 医学-传染病学

CiteScore

11.50

自引率

5.00%

发文量

151

审稿时长

22 days

期刊介绍： The International Journal of Hygiene and Environmental Health serves as a multidisciplinary forum for original reports on exposure assessment and the reactions to and consequences of human exposure to the biological, chemical, and physical environment. Research reports, short communications, reviews, scientific comments, technical notes, and editorials will be peer-reviewed before acceptance for publication. Priority will be given to articles on epidemiological aspects of environmental toxicology, health risk assessments, susceptible (sub) populations, sanitation and clean water, human biomonitoring, environmental medicine, and public health aspects of exposure-related outcomes.