Extreme precipitation events are occurring more intensely in Canada. This can contaminate water sources with enteric pathogens, potentially increasing the risk of acute gastrointestinal illness. This study aimed to investigate the relationship between extreme precipitation and emergency department (ED) visits for acute gastrointestinal illness in Toronto from 2012 to 2022. Distributed lag non-linear models were constructed on ED visit counts with a Quasi Poisson distribution. Extreme precipitation was modelled as a 21-day lag variable, with a linear relationship assumed at levels ≧95th percentile. Separate models were also conducted on season-specific data sets. Daily precipitation and gastrointestinal illness ED visits ranged between 0 to 126 mm, and 12 to 180 visits respectively. Overall, a 10-mm increase in precipitation >95th percentile had no significant relationship with the risk of ED visits. However, stratification by seasons revealed significant relationships during spring (lags 1–19, peak at lag 14 RR = 1.04; 95% CI: 1.03, 1.06); the overall cumulative effect across the 21-day lag was also significant (RR = 1.94; 95% CI: 1.47, 2.57). Extreme precipitation has a seasonal effect on gastrointestinal health outcomes in Toronto city, suggesting varying levels of enteric pathogen exposures through drinking water or other environmental pathway during different seasons.

加拿大的极端降水事件发生得更加频繁。这可能会导致肠道病原体污染水源，从而可能增加急性胃肠道疾病的风险。本研究旨在调查 2012 年至 2022 年多伦多极端降水与急性胃肠道疾病急诊 (ED) 就诊之间的关系。根据准泊松分布的 ED 就诊计数构建了分布式滞后非线性模型。极端降水被建模为 21 天的滞后变量，并假设水平≥95% 呈线性关系。还对特定季节的数据集进行了单独的模型。每日降水量和胃肠道疾病急诊就诊次数分别为 0 至 126 毫米和 12 至 180 次。总体而言，降水量增加 10 毫米 >95% 与急诊就诊的风险没有显着关系。然而，按季节分层揭示了春季期间的显着关系（滞后 1-19，滞后 14 达到峰值 RR = 1.04；95% CI：1.03，1.06）；21 天滞后期间的总体累积效应也很显着（RR = 1.94；95% CI：1.47，2.57）。极端降水对多伦多市的胃肠道健康结果具有季节性影响，表明不同季节通过饮用水或其他环境途径接触肠道病原体的程度不同。