Air pollution and stroke mortality in Arak, Iran: Short-term and long- term exposure effects analyzed using zero-inflated negative binomial

Leila  Poorsaadat; Amir Almasi  Hashiani; Payam  Amini; Ali  Koolivand; Maede  Nasrollahi; Seyed Hamed  Mirhoseini

doi:10.18502/japh.v10i4.20615

Leila Poorsaadat Department of Neurology, School of Medicine, Arak University of Medical Sciences, Arak, Iran
Amir Almasi Hashiani Department of Epidemiology, Faculty of Health, Arak University of Medical Sciences, Arak, Iran
Payam Amini School of Medicine, Keele University, Keele, Staffordshire, United Kingdom
Ali Koolivand Department of Environmental Health Engineering, Faculty of Health, Arak University of Medical Sciences, Arak, Iran
Maede Nasrollahi Student Research Committee, Arak University of Medical Sciences, Arak, Iran
Seyed Hamed Mirhoseini Department of Environmental Health Engineering, Faculty of Health, Arak University of Medical Sciences, Arak, Iran

DOI: https://doi.org/10.18502/japh.v10i4.20615

Keywords: Air pollution; Stroke mortality; Industrial emissions; Time-series analysis; Iran

Abstract

Introduction: Air pollution poses significant public health risks in industrial regions, with stroke mortality emerging as a critical outcome. This study examines the association between air pollutant exposure and stroke mortality in Arak, Iran - an industrial city with consistently poor air quality exceeding WHO thresholds.

Materials and methods: We conducted a time-series analysis of 1,010 stroke deaths (2019-2022) using zero-inflated negative binomial regression to model over-dispersed mortality data. Pollutant concentrations (PM2.5, PM10,

NO₂, O₃, SO₂) were collected from four monitoring stations representing

industrial, traffic, and residential zones. Effects were assessed for short-term (1-3 months) and long-term (6-24 months) exposures, with adjustment for meteorological and demographic confounders.

Results: NO₂ demonstrated the strongest short-term association (2-month RR: 1.50, 95% CI: 1.30-1.75, p<0.001). PM₁₀ showed a slight increase in risk at the 2-month lag (RR: 1.06, 95% CI: 0.98–1.14), although it was not statistically significant. Long-term PM2.5 exposure significantly increased mortality risk (24-month RR: 1.20, 95% CI: 1.05-1.58). A possible invers association was observed for SO₂ (2-month RR: 0.59, 95% CI: 0.36–0.97), while O₃ effects varied over time.

Conclusion: Industrial emissions (particularly NO₂ and particulate matter) significantly contribute to stroke mortality in Arak. The identified exposure– response relationships highlight the importance of stricter emission controls on vehicular and industrial sources and targeted health interventions for high-risk populations. Further investigation of pollutant interactions is also essential to better understand their combined effects on stroke mortality.