We have recently presented a new method of assessing spatiotemporal resolved PM 2.5 and PM 10 exposures 18,19 in the Negev (South Israel)-a semi-arid area, located in the global dust belt, which extends from West Africa to the Arabian Desert. 20 Unlike many commonly used exposure models, our model makes use of satellite aerosol optical depth measurements, which allowed us to estimate daily, spatially resolved, PM 10 and PM 2.5 concentration with the inclusion of populations in rural areas not living nearby monitoring stations.Stroke in older patients is mostly related to atherosclerosis. 21 In the young, however, stroke is less common, and the cause is much more diverse and often unexplained. 21 We hypothesize that PM exposure is positively associated with stroke, especially among young adults.
Methods
Study PopulationWe included all Clalit Health Services members with available geocoded addresses in Southern Israel, admitted to Soroka University Medical Center (SUMC) with hemorrhagic (International Classification of Diseases Ninth Revision [ICD9] 430-432) or ischemic stroke (ICD9 432-435) between the years 2005 and 2012. SUMC is the only medical center providing acute neurological care in the area, serving a population of ≈1 million residents; therefore, all the patients with stroke are referred to SUMC. Clalit Health Service is the largest health care provider in the area, covering ≈70% of the population. To avoid within subject correlation among recurrent events, we used only the first stroke event, within the study period, for each subject.
22Background and Purpose-Studies have demonstrated consistent associations between cardiovascular illness and particulate matter (PM) <10 and <2.5 μm in diameter, but stroke received less attention. We hypothesized that air pollution, an inflammation progenitor, can be associated with stroke incidence in young patients in whom the usual risk factors for stroke are less prevalent. We aimed to evaluate the association between stroke incidence and exposure to PM <10 and <2.5 μm, in a desert area characterized by a wide range of PM. Methods-We included all members of the largest health maintenance organization in Israel, who were admitted to a local hospital with stroke between 2005 and 2012. Exposure assessment was based on a hybrid model incorporating daily satellite remote sensing data at 1-km spatial resolution. We performed case-crossover analysis, stratified by personal characteristics and distance from main roads.