Estimation of short-term effects of air pollution on stroke hospital admissions in southern Sweden

Neuroepidemiology. 2010;34(3):131-42. doi: 10.1159/000274807.


Background: Short-term exposure to high levels of air pollution can increase stroke risk. In this study we investigated the short-term effects of air pollution on hospital admissions for stroke in a setting where pollutant levels are rather low. We also addressed methodological issues in evaluating the short-term effects of air pollution.

Methods: Daily admissions of ischemic (n = 11,267) and hemorrhagic (n =1,681) stroke were obtained from a Swedish quality register for stroke, Riks-Stroke. We used two types of exposure data: (1) daily measured background levels of ozone, temperature and particles with a diameter < 10 microm (PM(10)) and (2) modeled levels of a mixture of NO and NO2 (NOx) at the residential address of each individual.

Results: We estimated a 13% (95% confidence interval, 4-22%) increased risk for hospital admissions for ischemic stroke for levels of PM 10 above 30 microg/m(3) compared to < 15 microg/m(3) , whereas temperature above 16 degrees C decreased the risk. No consistent associations were found for hemorrhagic stroke or for ischemic stroke and ozone or NOx .

Conclusion: Particulate air pollution and temperature seemed to be associated with ischemic stroke hospital admissions. Individual exposure modeling facilitates a detailed exposure assessment but may also be more prone to misclassification errors. The time series and case crossover approaches yielded similar effect estimates.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Air Pollutants / adverse effects
  • Air Pollution / adverse effects*
  • Air Pollution / statistics & numerical data
  • Cross-Over Studies
  • Female
  • Hospitalization / statistics & numerical data
  • Hospitalization / trends
  • Hot Temperature / adverse effects
  • Humans
  • Inhalation Exposure / adverse effects
  • Male
  • Particulate Matter / adverse effects*
  • Patient Admission / statistics & numerical data
  • Patient Admission / trends*
  • Stroke / epidemiology*
  • Stroke / etiology*
  • Sweden / epidemiology
  • Time Factors


  • Air Pollutants
  • Particulate Matter