Seasonality in Cough: The Influence of Environmental Physiology.

Background/Objectives: Cough is a prevalent clinical problem associated with comorbidities and environmental conditions. We seek to highlight the clinically measurable impact of the environment on cough physiology by modeling the incidence and prevalence of seasonal cough as a function of certain environmental factors. Methods: An IRB-exempt population-based retrospective electronic record review was performed to analyze the incidence and prevalence of cough in an integrated rural healthcare system from January 1, 2021, through December 31, 2023. Using time series methods including dynamic regression models, these data were measured against the seasonal incidence and prevalence of influenza based on data from the Centers for Disease Control (CDC) and air quality metrics including Air Quality Index (AQI) and particulate matter counts (PM10) based on data from the Environmental Protection Agency (EPA). Results: There were 101,635 patients that met inclusion criteria involving 145,428 medical encounters for cough. There is a positive relationship between the seasonal prevalence and incidence of cough with influenza levels. AQI and PM10 demonstrated seasonality. While these were correlated with each other, we found no association between air quality metrics and the incidence and prevalence of cough. Results were validated within age groups, as each group independently demonstrated these associations. Conclusion: This study demonstrates a clear seasonal trend in our rural population in the diagnosis of cough, which also correlated with seasonal trends of influenza, illustrating the significance of seasonal factors in the development of informed healthcare practices. Level of Evidence: 4.