In order to assess the influence of atmospheric conditions and particulate matter (PM) on the seasonally varying incidence of influenza-like illnesses (ILI) in the capital of Poland—Warsaw, we analysed time series of ILI reported for the about 1.75 million residents in total and for different age groups in 288 approximately weekly periods, covering 6 years 2013–2018. Using Poisson regression, we predicted ILI by the Universal Thermal Climate Index (UTCI) as biometeorological indicator, and by PM2.5 and PM10, respectively, as air quality measures accounting for lagged effects spanning up to 3 weeks. Excess ILI incidence after adjusting for seasonal and annual trends was calculated by fitting generalized additive models. ILI morbidity increased with rising PM concentrations, for both PM2.5 and PM10, and with cooler atmospheric conditions as indicated by decreasing UTCI. While the PM effect focused on the actual reporting period, the atmospheric influence exhibited a more evenly distributed lagged effect pattern over the considered 3-week period. Though ILI incidence adjusted for population size significantly declined with age, age did not significantly modify the effect sizes of both PM and UTCI. These findings contribute to better understanding environmental conditionings of influenza seasonality in a temperate climate. This will be beneficial to forecasting future dynamics of ILI and to planning clinical and public health resources under climate change scenarios.

中文翻译：

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生物气象条件和空气污染对华沙流感样疾病发病率的影响


为了评估大气条件和颗粒物 (PM) 对波兰首都华沙流感样疾病 (ILI) 季节性变化发病率的影响，我们分析了波兰首都华沙约 175 万居民报告的 ILI 时间序列。总计，针对不同年龄组，大约每周 288 个周期，涵盖 2013 年至 2018 年 6 年。使用泊松回归，我们通过通用热气候指数 (UTCI) 作为生物气象指标，并分别通过 PM2.5 和 PM10 作为解释长达 3 周滞后效应的空气质量指标来预测 ILI。通过拟合广义相加模型计算调整季节性和年度趋势后的过量 ILI 发病率。 ILI 发病率随着 PM2.5 和 PM10 浓度的升高而增加，并且随着 UTCI 的降低表明大气条件变冷，ILI 发病率也会增加。虽然 PM 效应集中在实际报告期间，但大气影响在所考虑的 3 周期间表现出分布更均匀的滞后效应模式。尽管根据人口规模调整后的 ILI 发病率随着年龄的增长而显着下降，但年龄并没有显着改变 PM 和 UTCI 的效应大小。这些发现有助于更好地了解温带气候下流感季节性的环境条件。这将有利于预测流感样疾病的未来动态以及在气候变化情景下规划临床和公共卫生资源。