[An epidemiologic study on the incidence rate of tuberculosis in Tochigi Prefecture]

The purpose of the study is to clarify chronological changes and the regional difference of the incidence of tuberculosis in Tochigi Prefecture. The difference between the first period (1980-1984) and the second period (1990-1994) was analyzed. The results are as follows; 1. The decrease of incidence in the age groups of 20-29 years and over 70 years slowed down in all types of tuberculosis and infectious pulmonary tuberculosis. 2. The incidence of tuberculosis in the southern part of Tochigi Prefecture was higher than in the other parts, and this could be explained by the fact that the people in the southern part were exposed heavier to tuberculosis infection in the past than the people in other parts. 3. In the public health center areas where the incidence rate of tuberculosis was high, the slow decline or even increase of the incidence rate among age groups less than 30 years and over 70 years of age was observed and this seemed to affect the higher incidence in these areas.