TY - JOUR

T1 - Association between short-term exposure to ultrafine particles and hospital admissions for stroke in Copenhagen, Denmark

AU - Andersen, Zorana Jovanovic

AU - Olsen, Tom Skyhøj

AU - Andersen, Klaus Kaae

AU - Loft, Steffen

AU - Ketzel, Matthias

AU - Raaschou-Nielsen, Ole

PY - 2010

Y1 - 2010

N2 - AIMS: The relevance of ultrafine particles (UFPs, particles <0.1 microm diameter), the smallest fraction of ambient particulate matter, on stroke morbidity has not been documented. We studied the effects of short-term changes in exposure to these particles on stroke, separately for ischaemic and haemorrhagic strokes, mild and severe strokes, and ischaemic strokes with (likely embolic) and without (likely thrombotic) atrial fibrillation (AF). METHODS AND RESULTS: We used a time-stratified case-crossover design to study the association between short-term exposure to UFPs, particulate matter <10 microm in diameter (PM(10)), nitrogen oxides (NO(x)) and carbon monoxide (CO) (measured at single background station) and hospital admissions for stroke in Copenhagen (2003-2006). Of 7485 stroke admissions, 6798 were ischaemic and 687 haemorrhagic, 3485 mild, and 2248 severe. Of the ischaemic stroke cases, 1204 had AF and 5273 did not. We found significant positive association with exposure to UFPs, NO(x) and CO, and ischaemic strokes, and UFPs and NO(x) and mild strokes, 4 days before admission. The strongest associations were with UFPs. Exposure to UFPs lead to a 21% increase in hospital admissions (per interquartile range of 5-day averages; 95% confidence interval 4-41%) for mild ischaemic stroke of without AF (likely thrombotic origin). CONCLUSION: Our results indicate possible effects of traffic-related air pollution, mainly UFPs, on hospital admissions for ischaemic stroke, especially for mild ischaemic stroke of likely thrombotic origin (without AF). These are novel findings regarding the relevance of UFPs and the heterogeneous effect of air pollution on the severity and origin of stroke, and need confirmation by other data.

AB - AIMS: The relevance of ultrafine particles (UFPs, particles <0.1 microm diameter), the smallest fraction of ambient particulate matter, on stroke morbidity has not been documented. We studied the effects of short-term changes in exposure to these particles on stroke, separately for ischaemic and haemorrhagic strokes, mild and severe strokes, and ischaemic strokes with (likely embolic) and without (likely thrombotic) atrial fibrillation (AF). METHODS AND RESULTS: We used a time-stratified case-crossover design to study the association between short-term exposure to UFPs, particulate matter <10 microm in diameter (PM(10)), nitrogen oxides (NO(x)) and carbon monoxide (CO) (measured at single background station) and hospital admissions for stroke in Copenhagen (2003-2006). Of 7485 stroke admissions, 6798 were ischaemic and 687 haemorrhagic, 3485 mild, and 2248 severe. Of the ischaemic stroke cases, 1204 had AF and 5273 did not. We found significant positive association with exposure to UFPs, NO(x) and CO, and ischaemic strokes, and UFPs and NO(x) and mild strokes, 4 days before admission. The strongest associations were with UFPs. Exposure to UFPs lead to a 21% increase in hospital admissions (per interquartile range of 5-day averages; 95% confidence interval 4-41%) for mild ischaemic stroke of without AF (likely thrombotic origin). CONCLUSION: Our results indicate possible effects of traffic-related air pollution, mainly UFPs, on hospital admissions for ischaemic stroke, especially for mild ischaemic stroke of likely thrombotic origin (without AF). These are novel findings regarding the relevance of UFPs and the heterogeneous effect of air pollution on the severity and origin of stroke, and need confirmation by other data.

U2 - 10.1093/eurheartj/ehq188

DO - 10.1093/eurheartj/ehq188

M3 - Journal article

C2 - 20538735

VL - 31

SP - 2034

EP - 2040

JO - European Heart Journal

JF - European Heart Journal

SN - 0195-668X

IS - 16

ER -