Background Cardiovascular disease (CVD) is a leading cause of mortality and morbidity globally and in the United States. Additionally, CVD is a primary reason for hospital admission and imposes a significant economic burden. Ambient air pollution is recognized as a significant and preventable risk factor for CVD. While particulate matter (PM) as an air pollutant has been studied extensively, the research regarding ultrafine particles (UFPs or PM0.1) and their impact on health is lacking. This study aims to bridge the gap by examining the association of UFPs and adverse cardiovascular outcomes: Aim 1 investigates the association between air pollution (with a focus on UFPs) and stroke hospitalizations; Aim 2 assesses the impact of UFPs on CVD readmissions, including stroke-related hospital readmissions. Methods A time-stratified case-crossover design was utilized to assess the association between UFP exposure and health outcome in our study. The conditional logistic regression model was used to perform the time-stratified case-crossover study. Our health data source was from the New York State Department of Health Statewide Planning and Research Cooperative System (SPARCS). CVD was identified using International Classification of Diseases (ICD) codes with primary diagnosis codes for CVD from SPARCS. Our environmental data including air pollutants and meteorological factors were obtained from the data source simulated using a validated chemical transport model with aerosol microphysical simulation, GEOS-Chem/APM. All analyses were conducted using SAS 9.4 and R 4.3. Results Aim1: We found significantly positive associations between UFP exposure and overall strokes, but mainly in ischemic stroke (IS) (ERIQR range: 0.8% to 4.4%), not hemorrhagic stroke (HS). The adverse effects of UFPs were stronger for females, non-Hispanics, Blacks, older adults (especially 65-69 years) and during winter. We also found daily IS double-peak at 6 am and 8 pm. The UFP-IS threshold appeared to be when UFP count was around 6000 particles/cm3. While there were no significant differences in hospital stay lengths and total costs for high vs. low UFP exposures, the number of comorbidities were significantly higher on days with high UFP concentration (difference = 0.26, P < 0.05). Aim2: UFP exposure was positively associated with overall CVD readmissions for all readmission windows (30-, 60-, 90-, 180- and 360-day), with the highest association at lag0-6 days (ERIQR ranged from 4.4% to 6.2%, all P< 0.05). The adverse effects of UFPs were stronger for male, Hispanics, White, adults aged 60 and older, those with Medicaid insurance, those who lived in NYC, and during winter. We also found the UFP impacts varied by CVD subtypes and their associated readmission windows. Conclusion UFPs had significant adverse effects on stroke hospitalizations and CVD readmissions. The effects varied by demographics and seasonality. The findings of this study highlight the importance of understanding the impact of UFP exposure to public health and provide evidence to guide air-pollution-related interventions.
Liqiong Guo (Wed,) studied this question.