Secular trends in atherosclerosis of coronary arteries and basal cerebral arteries in Japan. The Akita pathology study.

The atherosclerotic lesions of the coronary arteries and basal cerebral arteries in the circle of Willis were examined in the bodies of decreased men ages 30 and over who had been admitted to a local hospital in northeast Japan during 1966 to 1974 (243 men) and 1975 to 1984 (602 men). The autopsy rates during the two periods were 86% and 89%, respectively. The extent of atherosclerosis was determined blindly by one pathologist using a grading method of cross-sectional stenosis scoring for coronary arteries and Baker's method for basal cerebral arteries. The age-adjusted mean scores for atherosclerosis in the coronary arteries and basal cerebral arteries were 30% and 42% lower, respectively, in the 1975 to 1984 period than in the 1966 to 1974 period (p less than 0.001). There was also a fall in age-adjusted blood pressure levels at admission: 10 mm Hg for systolic and 4 mm Hg for diastolic blood pressure (p less than 0.001). The opposite trend was seen in mean serum cholesterol: a rise from 171 mg/dl to 177 mg/dl (p = 0.018). Linear regression analysis indicated that blood pressure was positively associated with both atherosclerosis scores, controlling for age and serum cholesterol in both time periods (p less than 0.001). The association of serum cholesterol with the atherosclerosis scores was positive in both periods and statistically significant in 1975 to 1984. Similar findings were obtained when the analyses were conducted for cardiovascular disease (myocardial infarction and stroke) and for noncardiovascular disease, separately.(ABSTRACT TRUNCATED AT 250 WORDS)