Mid and long-term effects of air pollution on cardiovascular outcomes: estimating risk with the PM-years index (EP-PARTICLES study)
Authors: Kuzma L , Kurasz A , Swieczkowski M , Dobrzycki S 
Published: November 2023

Abstract

Background
Scores and medical calculators are important tools for planning health strategies. Air pollution is one of the main risk factors, especially for the cardiovascular system. In this study, we present and test our concept of estimating the risk associated with exposure to air pollution: Particulate Matters years index (PM-years index).

Objective
The long-term predictive performance of the PM-years index.

Methods
The PM-years index is an indicator of hypothetical exposure to air pollution. It is estimated by multiplying the number of years spent in a given environment by the difference between the average annual PM2.5 concentration and the allowed level of pollution given by World Health Organization guidelines. We collected data from 2010 to 2020 on PM2.5 concentration, mortality, and hospitalizations from Inspectorates for Environmental Protection, Central Statistical Office, and National Health Fund in Poland, respectively. County-specific associations of PM-years with multi-outcomes were estimated using Poisson regression panel models. The analysis used an age-standardized rate (SR), which was established on the European Standard Population structure. Models were adjusted for weather conditions. In the first stage, we checked the mid-term association between PM2.5 concentration, and in the second, we examined the association between PM-years index.

Results
In the analysis, we used data of 831,246 deaths, including 377,344 deaths due to cardiovascular disease (CVD), 198,133 deaths from neoplasm, 159,952 hospitalizations due to ischemic stroke (IS), and 152,055 due to myocardial infarction (MI). The mean standardized rate (SR) for STEMI was 87 (SD=23.1), NSTEMI – 110.1 (31.8), ischemic stroke – 212.4 (51.7), CVD mortality - 544.8 (190.5), cerebrovascular (CbVD) mortality 84.7 (56.8), neoplasm mortality 266.3 (133.9). Total mortality was 1171.2 (398.7). In the mid-term, we recorded the association between PMs and STEMI (OR=1.133 95%CI 1.12-1.15), NSTEMI (OR=1.02, 95%CI 1.004-1.03), IS (OR=1.04 95%CI 1.03-1.04), CVD mortality (OR=1.06 95%CI 1.03-1.04), CbVD mortality (OR=1.07 95%CI 1.06-1.08) but not total mortality and neoplasm mortality. The risk of STEMI significantly increased with each PM-year exposure (OR=1.21 95%CI 1.19-1.12). OR for NSTEMI for each PM-year was 1.08 (95%CI 1.07-1.09), for IS 1.09 (95%CI 1.08-1.11), for CVD mortality 1.07 (95%CI 1.06-1.073), and for CbVD 1.23 (95%CI 1.22-1.25). It is worth noting that PM-year also had an effect on neoplasm mortality (OR=1.02 95%CI 1.01-1.03). P&lt;0.001 for all tests.

Conclusions
The PM-years index is an independent predictor of major cardiovascular events and neoplasm mortality in patients. It can be used as a tool for risk stratification for patients or incorporated into a prediction model to improve efficacy in primary and secondary prevention. Moreover, the level of long-term exposure can allow for the adjustment of appropriate primary and secondary prevention schemes.