Blood Pressure and Total Cholesterol Level Are Critical Risks Especially for Hemorrhagic Stroke in Akita, Japan

Abstract

Background and Purpose: Stroke risk factors differ depending on the subtype of stroke; moreover, the distribution of risks is different among countries and races. Methods: Mass health screening data were collected from the Akita Prefectural Federation of Agricultural Cooperative for Health and Welfare from 1991 to 1998. Cerebrovascular events were determined from the Akita stroke registry from 1991 to 2001. Then, clinical risk factors for stroke, such as hypertension, hyperlipidemia and diabetes mellitus, were assessed in the different subtypes of stroke. Results: A total of 156,892 persons were included in this study (76,330 men and 80,562 women), and 1,323 subjects had a stroke during the 3 years of the screening period. The distribution of subtypes such as cerebral hemorrhage (CH), cerebral infarction (CI) and subarachnoid hemorrhage (SAH) was 27.3, 55.9 and 16.8%, respectively. Mean age and systolic and diastolic blood pressures (BPs) were significantly higher in stroke cases. CH and CI occurred more frequently in men, whereas SAH occurred more frequently in women. Serum total cholesterol (TC) <160 mg/dl was a risk factor for hemorrhagic stroke (CH and SAH), whereas TC >280 mg/dl increased the risk of CI. A multivariable analysis revealed that the lower TC level (<160 mg/dl) and the higher BP increased the relative risk of hemorrhagic stroke. Conclusions: BP was the strongest risk factor for any subtype of stroke. High BP and low TC (<160 mg/dl) were critical risks of hemorrhagic stroke.