02929nas a2200409 4500008004100000022001400041245011800055210006900173260001300242300001100255490000700266520181100273653000902084653001002093653001502103653001102118653001102129653001402140653003102154653000902185653001302194653001902207653001702226653003202243653002002275653001702295653001102312100001902323700002102342700002002363700001702383700002302400700002202423700001802445700002102463856003502484 2006 eng d a1524-462800aFactors associated with geographic variations in stroke incidence among older populations in four US communities.0 aFactors associated with geographic variations in stroke incidenc c2006 Aug a1980-50 v373 a
BACKGROUND AND PURPOSE: In the Cardiovascular Health Study (CHS), we previously observed lower stroke incidence in Allegheny County, PA compared with the other 3 study sites. The purpose of this study was to study possible reasons for the lower stroke incidence in Allegheny County.
METHODS: CHS participants 65 years or older who were stroke-free at baseline (n=5639) were followed between 1989 to 1990 and 2000 for the development of stroke. Risk factors at baseline and their subsequent control were compared among both groups. Site-specific hazard ratios for stroke incidence were calculated using Cox regression models.
RESULTS: The unadjusted hazard ratio for total stroke incidence in Forsyth County, NC; Sacramento County, CA; and Washington County, MD combined compared with Allegheny County, PA was 1.74 (95% CI: 1.42, 2.14). After adjustment for age and other traditional risk factors, there was modest reduction of the excess hazard in non-Allegheny sites compared with Allegheny County (hazard ratio=1.52, 95% CI: 1.17, 1.98). Between baseline and the seventh-year visits, control of hypertension, diabetes, lipids, smoking, atrial fibrillation and transient ischemic attack were similar across sites. White matter grade > or = 3 on the baseline brain MRI was less common in Allegheny County (25.8% versus 36.3%, respectively; P<0.001) and accounted for 25% of the excess hazard in non-Allegheny sites compared with Allegheny County.
CONCLUSIONS: Site differences in stroke risk factors at baseline and subsequent control only partially explain site differences in stroke incidence. White matter grade as a possible integrated measure of exposure and control of risk factors may help in explaining geographic variations in stroke incidence.
10aAged10aBrain10aCalifornia10aFemale10aHumans10aIncidence10aMagnetic Resonance Imaging10aMale10aMaryland10aNorth Carolina10aPennsylvania10aProportional Hazards Models10aRisk Assessment10aRisk Factors10aStroke1 aEl-Saed, Aiman1 aKuller, Lewis, H1 aNewman, Anne, B1 aLopez, Oscar1 aCostantino, Joseph1 aMcTigue, Kathleen1 aCushman, Mary1 aKronmal, Richard uhttps://chs-nhlbi.org/node/900