Short-Term Exposure to Ambient Air Pollution and Mortality From Myocardial Infarction.

Background: Short-term exposure to ambient air pollution has been linked to occurrence of myocardial infarction (MI); however, only a limited number of studies investigated its association with death from MI, and the results remain inconsistent.
Objectives: This study sought to investigate the association of short-term exposure to air pollution across a wide range of concentrations with MI mortality.
Methods: A time-stratified case-crossover study was conducted to investigate 151,608 MI death cases in Hubei province (China) from 2013 to 2018. Based on each case's home address, exposure to particulate matter with an aerodynamic diameter ≤2.5 μm (PM _2.5 ), particulate matter with an aerodynamic diameter ≤10 μm (PM ₁₀ ), sulfur dioxide, nitrogen dioxide (NO ₂ ), carbon monoxide, and ozone on each of the case and control days was assessed as the inverse distance-weighted average concentration at neighboring air quality monitoring stations. Conditional logistic regression models were implemented to quantify exposure-response associations.
Results: Exposure to PM _2.5 , PM ₁₀ , and NO ₂ (mean exposure on the same day of death and 1 day prior) was significantly associated with increased odds of MI mortality. The odds associated with PM _2.5 and PM ₁₀ exposures increased steeply before a breakpoint (PM _2.5 , 33.3 μg/m ³ ; PM ₁₀ , 57.3 μg/m ³ ) and flattened out at higher exposure levels, while the association for NO ₂ exposure was almost linear. Each 10-μg/m ³ increase in exposure to PM _2.5 (<33.3 μg/m ³ ), PM ₁₀ (<57.3 μg/m ³ ), and NO ₂ was significantly associated with a 4.14% (95% confidence interval [CI]: 1.25% to 7.12%), 2.67% (95% CI: 0.80% to 4.57%), and 1.46% (95% CI: 0.76% to 2.17%) increase in odds of MI mortality, respectively. The association between NO ₂ exposure and MI mortality was significantly stronger in older adults.
Conclusions: Short-term exposure to PM _2.5 , PM ₁₀ , and NO ₂ was associated with increased risk of MI mortality.
Competing Interests: Author Disclosures This work was supported by the Hubei Provincial Health Commission in China (WJ2019Z016, WJ2018H238, and WJ2015MA027), the Fundamental Research Funds for the Central Universities (19ykpy89), the National Natural Science Foundation of China (91743205), and the Jiangsu Social Development Project (BE2018745). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)