Incidence of hemorrhagic stroke in Black Caribbean, Black African, and White Populations: The South London Stroke Register, 1995-2004

Background and Purpose—Data are lacking on the differences in hemorrhagic stroke incidence between black Caribbean (BC), black African (BA), and white ethnic groups. We estimated the incidence for primary intracerebral hemorrhage
(PICH) and subarachnoid hemorrhage (SAH) and the associated risk factors for BCs, BAs, and whites.
Methods—First-ever stroke patients were drawn from a prospective community stroke register based in a multi-ethnic population in South London with 9% BCs, 15% BAs, and 63% whites. Incidence rates were standardized to European and world populations and adjusted for age and sex. Incidence rate ratios (IRRs) relative to whites were calculated by Poisson regression.
Results—Between 1995 and 2004, 566 incident stroke patients were registered: 395 PICHs and 171 SAHs. For PICH, age and sex-adjusted IRRs were higher in BAs (IRR, 2.80; 95% CI, 2.00 to 3.91) than in BCs (IRR, 1.46; 95% CI, 1.07 to
1.99) and were particularly pronounced for patients age 0 to 64 years: IRR3.95 (95% CI, 2.65 to 5.87) in BAs and 2.38 (95% CI, 1.50 to 3.80) in BCs. For those 65 years, prestroke hypertension was more prevalent in BAs and BCs (P=0.049). For SAH, the IRR was higher in BCs (IRR; 1.62; 95% CI, 1.05 to 2.48) than in BAs (IRR, 0.80; 95% CI, 0.43 to 1.46).
Conclusions—The higher incidence of PICH observed in BCs and BAs could be explained by prestroke hypertension being more common among young blacks. The different incidences of SAH in BCs and BAs suggest that the baseline risk of
stroke for distinct black ethnic groups is not homogeneous.