Background: Many previous studies have already proved the relationship between air pollutants and respiratory diseases. However, limited studies have so far assessed the impacts of air particulate matter exposure on the older adults patients with pneumonia. This study aims to reveal the impacts of short-term exposure to air particulate matter on the daily number of the older adults patients hospitalized due to pneumonia and calculate the economic costs attributable to this exposure.
Methods: A time-stratified case-crossover study design was adopted. Hospitalization data were collected from hospitals above county levels from 9 cities in Sichuan Province, China from January 1, 2018 to December 31, 2019. A sample of 43,746 pneumonia patients aged over 65 was retrieved. After adjusting for the influence of temperature and humidity, we analyzed the relationships between the daily number of the older adults pneumonia inpatients and the levels of air particulate matters (PM2.5, and PM10) and their relevant economic burdens. Then, stratification analyses were conducted based on patient age, gender, season, and whether the patient has comorbidity.
Results: Short-term exposure to air particulate matter pollution was correlated with the increase of the older adults pneumonia inpatients. The single pollutant model showed that PM2.5 and PM10 had the greatest impact on the number of the older adults pneumonia inpatients at lag7 and lag4, respectively. For every 10 μg/m3 increase in PM2.5 and PM10 concentrations, the daily number of the older adults pneumonia inpatients increased by 1.5% (95% CI: 1.010-1.021) and 1.0% (95% CI: 1.006-1.014), respectively. The 65-79 year-olds were more susceptible to air particulate pollutants (P < 0.05). During the study period, the total hospitalization costs and out-of-pocket expenses attributable to PM2.5 and PM10 exposure were 44.60 million CNY and 16.03 million CNY, respectively, with PM2.5 being the primary influencing factor.
Conclusion: Short-term exposure to air particulate pollution increased the risks of hospitalization for pneumonia in the 65 plus age group, increasing economic burdens on the society and involved families. These findings can further support the policies aiming to reduce the number of the older adults pneumonia inpatients by controlling air particulate pollutant concentrations.