The incidence of deep and lobar intracerebral hemorrhage in whites, blacks, and Hispanics

Background: Black and Hispanic Americans have a greater risk of primary intracerebral hemorrhage (ICH) than whites. Deep ICH is most often associated with hypertension, while lobar ICH is associated with cerebral amyloid angiopathy. The authors conducted a population-based incidence study to directly compare the incidence of deep vs lobar ICH in all three race-ethnic groups. Methods: The authors used an active hospital and community surveillance program and autopsy reports to identify incident ICH cases among white, black, and Caribbean Hispanic adults in Northern Manhattan between July 1993 and June 1997. Incidence rates were adjusted for age and sex to the 1990 US Census. CIs for risk ratios (RR) were calculated with Byar's χ² approximation of the Poisson distribution. Results: The authors identified 155 cases of ICH for an annual incidence of 30.9/100,000 (26.7 to 35.0). Men had a higher risk of ICH than women (RR 1.5, 95% CI 1.2 to 1.8), driven entirely by the incidence of deep ICH (RR 1.8) rather than lobar ICH (RR 1.0). Compared with whites, RR for blacks was all ICH 3.8 (2.2 to 8.9), deep 4.8 (2.3 to 21.1), lobar 2.8 (1.2 to 14.4); RR for Hispanics was all 2.6 (1.4 to 6.1), deep 3.7 (1.7 to 16.5), lobar 1.4 (0.4 to 7.4). Conclusions: ICH is a heterogeneous disease with deep and lobar subtypes distinguishable on an epidemiologic basis. The different patterns of these two subtypes in our race-ethnically diverse population lend credence to the notion that ICH should no longer be treated as a single entity.