Blood pressure in relation to the incidence of cerebral infarction and intracerebral hemorrhage. Hypertensive hemorrhage: debated nomenclature is still relevant.

BACKGROUND AND PURPOSE Data regarding the association between blood pressure level and incidence of stroke subtype, especially primary intracerebral hemorrhage (PICH) subtypes, is sparse. This population-based study explored the relationship between blood pressure and the incidence of cerebral infarction, and PICH, with lobar and nonlobar location. METHODS Risk factors were assessed in 27,702 men and women without prior stroke from the city of Malmö, Sweden. RESULTS Mean age was 58.1 years. In all, 701 subjects had stroke (613 cerebral infarction and 88 PICH) during the follow-up period (mean, 7.5 years). The age- and sex-standardized incidences of cerebral infarction in subjects with hypertension grade 3 (>or=180/110 mm Hg) and normal blood pressure (<140/90 mm Hg) were 6.8 and 1.7 per 1000 person-years, respectively. Compared with the normotensive group, the adjusted relative risk of cerebral infarction was 3.4 (95% CI: 2.6 to 4.5) in subjects with hypertension grade 3. The corresponding incidences of lobar PICH were 0.5 versus 0.08 per 1000 person-years, respectively (adjusted relative risk: 9.2, 95% CI: 2.6 to 32.6) and for nonlobar PICH 1.6 versus 0.09 per 1000 person-years, respectively (adjusted relative risk: 25.9, 95% CI: 8.2 to 82.3). CONCLUSIONS The incidence of hemorrhagic and ischemic stroke increased progressively with increasing blood pressure. Although hypertension was associated with substantially higher incidence rates and absolute numbers of cerebral infarction, which is most important in the public health perspective, the relationship with nonlobar PICH was strongest in terms of relative risks.