Survey of tuberculosis prevalence in Japan, 1953.

In 1953 the first systematic survey of tuberculosis prevalence in Japan was carried out by the Ministry of Health and Welfare. The preliminary report on the survey includes a description of the choice of sampling-unit areas, of the process of organization, of the method of execution, of the techniques employed, and of the diagnostic standards adopted. The results of the survey are summarized with reference to age; sex; tuberculin reaction; tuberculosis pathology (all forms, pulmonary, and extrapulmonary); disease type; the type of management, medical treatment, and hospitalization required; and previous case-history and notification statistics. The method followed in extrapolating the survey results to cover the total population of Japan is defined, and the most important estimates computed from the findings are tabulated.The survey revealed that even in the area where the lowest prevalence was found, the proportion of cases in the population was still as high as 3.6%, and that throughout the areas surveyed the pathology present averaged 16.0% and the proportion of cases 6.1%. Comparison of the data obtained in this survey with previous case-histories showed that 68.2% of persons with unhealed pathology had been unaware of being infected, thus giving strong proof of the fallibility of estimating the number of tuberculous patients on the basis of the number of cases reported by doctors. In addition, the survey proved that the tuberculosis morbidity estimates previously available for Japan-and calculated by multiplying the tuberculosis mortality figures by a fixed coefficient of 10-12-were totally inaccurate.