Description
- Abstract:
- Background: Climate change is having dramatic effects on human health, particularly with rising temperatures in the US and globally. Previous research has found associations of increased all-cause mortality as heat increases, along with an increased risk when fine particulate matter (PM2.5) levels are elevated. This association has not been thoroughly researched for cardiovascular outcomes such as hospitalizations for heart failure, the most common reason for hospitalization in older adults. We investigated the joint effects of temperature and PM2.5 on hospitalizations with an indication of heart failure by conducting a time-stratified case-crossover study. We hypothesized that there would be an increase in the risk of heart failure hospitalizations as daily mean temperature increased, and the co-occurrence of higher PM2.5 would have an additive interaction, or exacerbate this relationship. Methods: Using Medicare data of all heart failure hospitalizations from 2016-2023 during the warmer months (May to September), we conducted a time-stratified case-crossover study. Heat index and PM2.5 daily averages were estimated using XGBoost-IDW-Synthesis (XIS), a spatiotemporal prediction model, and matched at the zip code level. We conducted a conditional logistic regression model that included heat index with a natural spline, PM2.5 was categorized as above or below 9μg/m3, the current Annual Standard for PM2.5, and an interaction term. To understand the additive interaction between heat and PM2.5, we calculated the relative excess risk due to interaction (RERI), which quantifies the risk with exposures to both heat and PM2.5 greater than the risk of individual effects. Results: Our sample has 10,755,858 hospitalizations, with a median age was 79 years. Approximately 52% of patients were Female, 77% were White, and 23% were fully eligible for dual Medicare-Medicaid. There is significant evidence that the odds of heart failure hospitalization increase as average heat index increases; a higher heat index was also associated with higher odds of hospitalization for both categories of PM2.5 exposure. We observed modest additive interaction between heat and PM2.5 with RERI estimates above 0 at heat indices from approximately 20 ℃ to 30 ℃. Conclusion: Heat increases the risk of heart failure hospitalization in older adults, and this risk increases in the presence of elevated particulate air pollution. Heat warning systems should take into account the health risks of heat when PM2.5 is also elevated.
- Notes:
- Thesis (M. P. H.)--Brown University, 2026
Citation
Stevens, Jake,
"Hot and Dirty Air: The Joint Effects of Heat and Pollution on the Risk of Heart Failure Hospitalization in Older Adults"
(2026).
Public Health Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:m2g53rr4/
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Collection:
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Public Health Theses and Dissertations
Theses and Dissertations for the Public Health department....