Impact of short-term air pollution exposure on acute coronary syndrome in two cohorts of industrial and non-industrial areas: A time series regression with 6,000,000 person-years of follow-up (ACS - Air Pollution Study)

Abstract

Background: There is a lack of studies directly comparing the effect of air pollution on acute coronary syndrome (ACS) occurrence in industrial and non-industrial areas.

Objectives: A comparison of association of air pollution exposure with ACS in two cohorts of industrially different areas.

Materials and methods: The study covered 6,000,000 person-years of follow-up and five pollutants between 2008 and 2017. A time series regression analysis with 7-lag was used to assess the effects air pollution on ACS.

Results: A total of 9046 patients with ACS were included in the analysis, of whom 3895 (43.06%) had ST-elevation myocardial infarction (STEMI) - 45.39% from non-industrial area, and 42.37% from industrial area; and 5151 (56.94%) had non-ST-elevation myocardial infarction (NSTEMI) - 54.61% from non-industrial area and 57.63% from industrial area. The daily concentrations of PM_2.5, PM₁₀, NO₂, SO₂, CO were higher in industrial than in non-industrial area (P < 0.001). In non-industrial area, an increase of 10 μg/m³ of NO₂ concentration (Odds Ratio (OR) = 1.126, 95%CI = 1.009-1.257; P = 0.034, lag-0) and an increase of 1 mg/m³ in CO concentration (RR = 1.055, 95%CI = 1.010-1.103; P = 0.017, lag-0) were associated with an increase in the number of hospitalization due to NSTEMI (for industrial area increase of 10 μg/m³ in NO₂ (OR = 1.062, 95%CI = 1.020-1.094; P = 0.005, lag-0), SO₂ (OR = 1.061, 95%CI = 1.010-1.116; P = 0.018, lag-4), PM₁₀ (OR = 1.010, 95%CI = 1.001-1.030; P = 0.047, lag-6). In STEMI patients in industrial area, an increased hospitalization was found to be associated with an increase of 10 μg/m³ in SO₂ (OR = 1.094, 95%CI = 1.030-1.162; P = 0.002, lag-1), PM_2.5 (OR = 1.041, 95%CI = 1.020-1.073; P < 0.001, lag-1), PM₁₀ (OR = 1.030, 95%CI = 1.010-1.051; P < 0.001, lag-1). No effects of air pollution on the number of hospitalization due to STEMI were noted from non-industrial area.

Conclusion: The risk of air pollution-related ACS was higher in industrial over non-industrial area. The effect of NO₂ on the incidence of NSTEMI was observed in both areas. In industrial area, the effect of PMs and SO₂ on NSTEMI and STEMI were also observed. A clinical effect was more delayed in time in patients with NSTEMI, especially after exposure to PM₁₀. Chronic exposure to air pollution may underlie the differences in the short-term effect between particulate air pollution impact on the incidence of STEMI.

Keywords: Myocardial infarction; Particulate matter; Pollutants; Smog.