Title | Factors associated with geographic variations in stroke incidence among older populations in four US communities. |
Publication Type | Journal Article |
Year of Publication | 2006 |
Authors | El-Saed, A, Kuller, LH, Newman, AB, Lopez, O, Costantino, J, McTigue, K, Cushman, M, Kronmal, R |
Journal | Stroke |
Volume | 37 |
Issue | 8 |
Pagination | 1980-5 |
Date Published | 2006 Aug |
ISSN | 1524-4628 |
Keywords | Aged, Brain, California, Female, Humans, Incidence, Magnetic Resonance Imaging, Male, Maryland, North Carolina, Pennsylvania, Proportional Hazards Models, Risk Assessment, Risk Factors, Stroke |
Abstract | <p><b>BACKGROUND AND PURPOSE: </b>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.</p><p><b>METHODS: </b>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.</p><p><b>RESULTS: </b>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.</p><p><b>CONCLUSIONS: </b>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.</p> |
DOI | 10.1161/01.STR.0000231454.77745.d9 |
Alternate Journal | Stroke |
PubMed ID | 16794204 |