University Summit in Kyushu 2007
Kyushu University, Fukuoka, Japan, 27-28 October
Session 3 : The University's Role in Health Sciences

Assis.Prof. Dr. Hisatomi ARIMA
Faculty of Medical Sciences, Kyushu University

The Hisayama Study: a long-term prospective cohort study oflife-style
related diseases in a general population of Japanese

The Town of Hisayama is a suburban community adjacent to Fukuoka City, a metropolitan area in the southern region of Japan. The population of the town is approximately 8,000 and has remained stable for over 40 years. According to the census, the age and occupational distributions of the town population were almost identical to those of Japan as a whole.
The dietary pattern of the residents was also similar to that of the participants in the National Nutrition Survey, which selected its subjects from 300 areas throughout Japan. In this town, a population-based cohort study of life-style related diseases has been ongoing since 1961.
We established four study cohorts of Hisayama residents aged 3 40 years in 1961 (1,618 subjects, first cohort), 1974 (2,038 subjects, second cohort), 1988 (2,637 subjects, third cohort) and 2002 (3,124 subjects, forth cohort). The most characteristic features of this study are high participation rates in the screening examinations (> 80% in each cohort), a high autopsy rate of the deceased subjects during a follow-up period (approximately 80%), and very few subjects who were lost to follow-up (< 3 subjects in each cohort).

In the present analysis, we compared 12-year follow-up data of the first, the second and the third cohorts and examined trends in incidence of type-specific stroke and coronary heart disease as well as their survival rates after age-adjustment. The incidence of cerebral infarction significantly decreased by 37% for men and by 32% for women from the first to the second cohort.
It continued to decline by 29% for men, but the decline decelerated for women in the third cohort. The incidence of cerebral hemorrhage steeply decreased by 61% from the first to the second cohort in men only, while it was sustained for both sexes in the third cohort. In contrast, the incidence of coronary heart disease was unchanged. The prevalence of severe hypertension and current smoking significantly decreased, while that of glucose intolerance, hypercholesterolemia, and obesity greatly increased across the four cohorts. These results suggest that the decline in stroke incidence is slowing down and that the incidence of coronary heart disease is not decreasing in Japan. Insufficient control of hypertension and the increase in metabolic disorders may contribute to these trends.

Hisatomi Arima and Yutaka Kiyohara
Department of Environmental Medicine, Graduate School of Medical Sciences,
Kyushu University, Fukuoka, Japan