Association of short-term exposure to ambient PM1 with total and cause-specific cardiovascular disease mortality

Abstract

Background: The acute effects of exposure to ambient particulate matter with an aerodynamic diameter ≤1 μm (PM₁) on cardiovascular disease (CVD) mortality remain unclear.

Objectives: To investigate whether short-term exposure to ambient PM₁ was associated with mortality from total and/or cause-specific CVDs, and estimate the excess mortality.

Methods: A time-stratified case-crossover study was conducted among 1,081,507 CVD deaths in Jiangsu province, China from 2015 to 2020. We assessed daily residential ambient PM₁ exposures using a validated grid dataset for each subject. Conditional logistic regression models and distributed lag linear or nonlinear models were employed to quantify the association of PM₁ exposure with mortality during the same day of CVD death and 1 day prior.

Results: Each 10 μg/m³ increase of PM₁ exposure was significantly associated with a 1.46 % (95 % confidence interval: 1.28 %, 1.65 %), 1.95 % (1.28 %, 2.63 %), 1.16 % (0.86 %, 1.47 %), 1.41 % (1.13 %, 1.69 %), and 1.83 % (1.37 %, 2.30 %) increased odds of mortality from total CVDs, hypertensive diseases (HDs), ischemic heart diseases (IHDs), stroke, and sequelae of stroke, respectively (all p <0.05). No significant association was identified with mortality from pulmonary heart disease or chronic rheumatic heart diseases. The excess fraction of total CVD mortality attributable to PM₁ exposure was 5.71 %, while the cause-specific excess fractions ranged from 4.98 % for IHDs to 7.46 % for HDs. Significantly higher excess fractions were observed for total and certain cause-specific CVD mortality in adults 80 years or older.

Conclusions: We found that short-term exposure to ambient PM₁ was significantly associated with an increased odds of mortality from total and specific CVDs and may lead to considerable excess mortality especially among older adults. Our findings highlight a potential approach to prevent premature CVD deaths by reducing PM₁ exposures and provide essential quantitative data for the development of future air quality standards for ambient PM₁.

Keywords: Cardiovascular diseases; Case-crossover study; Distributed lag model; Particulate matter.