発見動機別にみた中小企業における肺結核の発生と経過

抄録

For the purpose of evaluating whether safety reduction in the number of mass chest X-ray ex-aminations of adult population is possible or not, the incidence of pulmonary tuberculosis as well as the type of disease, methods and duration of treatment was observed among employees of iron factories in Tokyo area during the period from 1976 to 1979. All the factories were small in size, and the average employees per one factory was approximately 50.
The detection rate of new cases of pulmonary tuberculosis was 0.03% among those examined by the mass X-ray examination, and the incidence rate of pulmonary tuberculosis diagnosed by symptomatic visit to physicians was 0.04% for all employees, hence the overall incidence of pulmonary tuberculosis was 0.06%. In 1976, the majority of new cases (11) were detected by symptomatic visit to physicians and only 2 cases were found by the mass X-ray examination, while in later years, the difference in the number of new cases found by the passive and active case-finding became smaller, namely 13 cases were diagnosed by symptomatic visit and 10 cases by the mass survey.
The incidence rate of pulmonary tuberculosis among those who have not been examined by the mass survey was 0.71%, and the rate was much higher than the rate (0.20%) among those who were examined by the mass survey in the previous year. Comparing the severity of the disease at the time of diagnosis, more extensive and cavitary cases as well as bacillary cases and cases complicated with pleurisy were found more among cases found by symptomatic visit than among cases found by the mass survey. So-called rapid cases who were healthy in the previous year and develop bacillary and/or cavitary tuberculosis were found mainly in symptomatic cases. Hospitalization was indicated more for symptomatic cases, and the duration of treatment was also longer in symptomatic cases.
Loss of income during temporary disability of work due to hospitalization, however, has become smaller, as the duration of hospitalization became shorter, and none had lost his job because of tuberculosis. Comparing the increase in the expense for medical treatment when the mass examination is stopped against the decrease in the expense for the mass survey, the former is smaller than the latter, and the radiation hazards are also reduced when the annual X-ray examination is stopped. Taking into account the above circumstances, it is reasonable to reduce the number of mass chest X-ray examinations especially for young adult, and the emphasis of case-finding programme should be given for the promotion of symptomatic visit to physicians.