Abstract TMP47: Risk Factors for Intracerebral Hemorrhage and the Racial Differences in the Impact of Age on Risk: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study
Introduction: Because of low incidence rates, risk factors for intracerebral hemorrhage (ICH) have largely been estimated in case/control studies, very selected population cohorts, or by pooling of multiple longitudinal cohorts.
Methods: REGARDS is a longitudinal cohort study of 30,239 African American (AA) and white community-dwelling participants aged 45 and over, recruited from the 48 contiguous US states. Physician-adjudicated incident stroke events in the REGARDS study were used to assess risk factors for ICH among those stroke-free at baseline.
Results: A total of 62 ICH events occurred over an average 5.6 year follow-up among 27,760 participants stroke-free at baseline. In multivariable models, there was a significant (p = 0.0066) interaction between race and age; ICH risk dramatically increases with age for whites (HR = 2.03 per 10 year difference; 95% CI: 1.14 - 2.86), but there was little evidence of increasing risk with age in AAs (HR = 1.01 per 10 year difference; 95%: 0.65 - 1.58). This differential impact of age underlies a substantial excess in AA-to-white risk at age 45 (HR = 5.30; 95% CI: 1.41 - 19.91), but a marginally lower risk at age 85 (HR = 0.33; 95% CI: 0.10 - 1.05) (see figure). Risk of ICH was also significantly higher for men than women (HR = 2.60; 95% CI: 1.50 - 4.48), in those with higher systolic blood pressure (HR = 1.19 per 10 mmHg difference; 95% CI: 1.05 - 1.36), and for warfarin use to non-use (HR = 2.24; 95% CI: 1.01 - 5.00). Diabetes, chronic kidney disease, cholesterol components, smoking, alcohol use, and aspirin use were not related to ICH risk.
Discussion: Additional research is needed to understand the striking AA-to-white differences in ICH risk across the age spectrum. In addition, higher systolic blood pressure, male sex, and warfarin were confirmed as substantial ICH risk factors in the general population. Other factors found to be significant in other studies were not confirmed in this single cohort, population-based, longitudinal cohort study.
- © 2012 by American Heart Association, Inc.