[Trend of tuberculosis among young people observed from data of nationwide surveillance system]

In order to know the trend of TB incidence among people younger than 30 years of age, and to clarify the problem of TB control among them, the author used the surveillance data, the vital statistics, the annual reports of health center activities and others for the past 20 years. While the stagnation of the decline of TB incidence rate has been observed since early 1980s, the speed of decline among young people has been greater than that among people older than 30 years. However, at the same time it is worth attention that the incidence rate of the 20s is higher than that of those aged 30-39 years, and the slowing off more remarkable, during the last several years. It was shown that the recent increase of young immigrants from high prevalence countries is affecting the incidence of young age group (age 20-29) in Tokyo and the surrounding prefectures with higher proportion of these immigrant population. On the other hand, the high incidence in the young people observed in Osaka and the surrounding prefectures may be attributed to some other social risks. The BCG coverage for children aged 0-4 years has been increasing and reached to 90% in 1991. The tuberculin test results of children in an area seems to reflect the technical level of the testing and the age of children to be tested, rather than the TB prevalence of the area. The frequency of the young people under chemoprophylaxis is widely variable among prefectures. There is poor correlation between this frequency of chemoprophylaxis of prefectures and the incidence rate of sputum positive TB, which may be caused by disparity in recognition of the necessity of the chemoprophylaxis and the lack of efforts for the quality control of the services, such as tuberculin testing.