Race and Ethnic Disparities in Stroke Incidence in the Northern Manhattan Study

Abstract

Background and Purpose— An excess incidence of strokes among blacks versus whites has been shown, but data on disparities related to Hispanic ethnicity remain limited. This study examines race/ethnic differences in stroke incidence in the multiethnic, largely Caribbean Hispanic, NOMAS (Northern Manhattan Study), and whether disparities vary by age. Methods— The study population included participants in the prospective population-based NOMAS, followed for a mean of 14±7 years. Multivariable-adjusted Cox proportional hazards models were constructed to estimate the association between race/ethnicity and incident stroke of any subtype and ischemic stroke, stratified by age. Results— Among 3298 participants (mean baseline age 69±10 years, 37% men, 24% black, 21% white, 52% Hispanic), 460 incident strokes accrued (400 ischemic, 43 intracerebral hemorrhage, 9 subarachnoid hemorrhage). The most common ischemic subtype was cardioembolic, followed by lacunar infarcts, then cryptogenic. The greatest incidence rate was observed in blacks (13/1000 person-years), followed by Hispanics (10/1000 person-years), and lowest in whites (9/1000 person-years), and this order was observed for crude incidence rates until age 75. By age 85, the greatest incidence rate was in Hispanics. Blacks had an increased risk of stroke versus whites overall in multivariable models that included sociodemographics (hazard ratio, 1.51 [95% CI, 1.13–2.02]), and stratified analyses showed that this disparity was driven by women of age ≥70. The increased rate of stroke among Hispanics (age/sex-adjusted hazard ratio, 1.48 [95% CI, 1.13–1.93]) was largely explained by education and insurance status (a proxy for socieoeconomic status; hazard ratio after further adjusting for these variables, 1.17 [95% CI, 0.85–1.62]) but remained significant for women age ≥70. Conclusions— This study provides novel data regarding the increased stroke risk among Caribbean Hispanics in this elderly population. Results highlight the need to create culturally tailored campaigns to reach black and Hispanic populations to reduce race/ethnic stroke disparities and support the important role of low socioeconomic status in driving an elevated risk among Caribbean Hispanics.