Short-Term Exposure to Fine Particulate Matter and Risk of Ischemic Stroke.
There is a strong association between ambient concentrations of particulate matter (PM) and cardiovascular disease. However, it remains unclear whether acute exposure to fine PM (PM2.5) triggers ischemic stroke events and whether the timing of exposure is associated with stroke risk. We, therefore, examined the association between ambient PM2.5and occurrence of ischemic stroke.



We analyzed data for 6885 ischemic stroke patients from a multicenter hospital-based stroke registry in Japan who were previously independent and hospitalized within 24 hours of stroke onset. Time of symptom onset was confirmed, and the association between PM (suspended PM and PM2.5) and occurrence of ischemic stroke was analyzed by time-stratified case-crossover analysis.



Ambient PM2.5and suspended PM at lag days 0 to 1 were associated with subsequent occurrence of ischemic stroke (ambient temperature-adjusted odds ratio [95% confidence interval] per 10 μg/m3: suspended PM, 1.02 [1.00-1.05]; PM2.5, 1.03 [1.00-1.06]). In contrast, ambient suspended PM and PM2.5at lag days 2 to 3 or 4 to 6 showed no significant association with stroke occurrence. The association between PM2.5at lag days 0 to 1 and ischemic stroke was maintained after adjusting for other air pollutants (nitrogen dioxide, photochemical oxidants, or sulfur dioxide) or influenza epidemics and was evident in the cold season.



These findings suggest that short-term exposure to PM2.5within 1 day before onset is associated with the subsequent occurrence of ischemic stroke.
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Ryu
R
Matsuo
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Takehiro
T
Michikawa
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Kayo
K
Ueda
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Tetsuro
T
Ago
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Hiroshi
H
Nitta
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.).
Takanari
T
Kitazono
From the Department of Health Care Administration and Management (R.M., M.K.), Department of Medicine and Clinical Science (R.M., T.A., T.K.), and Center for Cohort Studies (T.K., M.K.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Environmental Epidemiology Section, Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan (T.M., K.U., H.N.); and Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Japan (K.U.). kamouchi@hcam.med.kyushu-u.ac.jp.
Masahiro
M
Kamouchi
D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects*; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology*; D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D052638:Particulate Matter / Q000009:adverse effects*; D012042:Registries / Q000706:statistics & numerical data*; D012306:Risk; D020521:Stroke / Q000453:epidemiology / Q000209:etiology*
D000393:Air Pollutants; D052638:Particulate Matter
case-crossover; ischemic stroke; particulate matter; risk; stroke