Triggering of ST-elevation myocardial infarction by ultrafine particles in New York: Changes following Tier 3 vehicle introduction

Abstract

BackgroundPreviously, we found increased rates of ST-elevation myocardial infarction (STEMI) associated with increased ultrafine particle (UFP; <100 nm) concentrations in the previous few hours in Rochester, New York. Relative rates were higher after air quality policies and a recession reduced pollutant concentrations (2014–2016 versus 2005–2013), suggesting PM composition had changed and the same PM mass concentration had become more toxic. Tier 3 light duty vehicles, which should produce less primary organic aerosols and oxidizable gaseous compounds, likely making PM less toxic, were introduced in 2017. Thus, we hypothesized we would observe a lower relative STEMI rate in 2017–2019 than 2014–2016. MethodsUsing STEMI events treated at the University of Rochester Medical Center (2014–2019), UFP and other pollutants measured in Rochester, a case-crossover design, and conditional logistic regression models, we estimated the rate of STEMI associated with increased UFP and other pollutants in the previous hours and days in the 2014–2016 and 2017–2019 periods. ResultsAn increased rate of STEMI was associated with each 3111 particles/cm3 increase in UFP concentration in the previous hour in 2014–2016 (lag hour 0: OR = 1.22; 95% CI = 1.06, 1.39), but not in 2017–2019 (OR = 0.94; 95% CI = 0.80, 1.10). There were similar patterns for black carbon, UFP11–50nm, and UFP51–100nm. In contrast, increased rates of STEMI were associated with each 0.6 ppb increase in SO2 concentration in the previous 120 h in both periods (2014–2016: OR = 1.26, 95% CI = 1.03, 1.55; 2017–2019: OR = 1.21, 95% CI = 0.87, 1.68). ConclusionsGreater rates of STEMI were associated with short term increases in concentrations of UFP and other motor vehicle related pollutants before Tier 3 introduction (2014–2016), but not afterwards (2017–2019). This change may be due to changes in PM composition after Tier 3 introduction, as well as to increased exposure misclassification and greater underestimation of effects from 2017 to 2019.