AN ANALYSIS OF THE PREFECTURAL DIFFERENCE IN THE PREVALENCE OF TUBERCULOSIS AND ITS RELATING FACTORS, AND FUTURE PROSPECT

The areal difference of the mortality from tuberculosis on prefectural level has not been dissolved so far, despite the rapid and precipitous decrease of the mortality after the introduction of chemotherapeutics in 1950 s. The highest-lowest ratio of the mortalities among prefectures in 1967 is 2.6, which is approximately the same level as those of 15 years ago, 1952 and 30 years ago, 1937.<BR>The purpose of this s tudy is to detect the factors which caused the prefectural difference of the mortality from tuberculosis. In this report the analysis was conducted especially on the indices which represent the characteristics in the changes of the mortality from tuberculosis in each prefecture from the beginning of this century. The indices which were observed as the factors are the trend lines of the mortality from tuberculosis by sex for three characteristic periods Trend I: 1909-50, before the introduction of chemotherapeutics, Trend II: 1949-53, immediately after the introduction of chemotherapeutics and Trend III: 1953-66, recent trend. excess mortalities due to the flu pandemic and due to the World War II. and the mortality from tuberculosis by sex for selected calendar years.<BR>The following conclusions were drawn from the observations.<BR>1. The areal difference in the mortality from tu b erculosis, which were gradually shrinking for 20 years at the beginning of this century, is widening in male at present, and it is expected to continue to be widened unless taking effective counter-measures to correct the difference.<BR>2. The high- rank prefectures in the mortality rate from tuberculosis before the War such as Tokyo, Kanagawa, Kyoto, Osaka and Hyogo and prefectures in Hokuriku block were, with exception of Osaka and Hyogo, replaced by prefectures in Kyushu, Shikoku and Chugoku blocks after the War.<BR>3. The fact t hat the mortality from tuberculosis in Kyushu, Shikoku and Chugoku blocks where the ranks of the mortality are highest at present, were declining less than other prefectures before the introduction of chemotherapeutics suggests that the past history of the epidemics of tuberculosis even before the War is one of the factors responsible for the areal difference of the mortality from tuberculosis at present.<BR>4. It should be noted that the popularizatio n of the controlmeasures immediately after the introduction of chemotherapeutics still has the effect on the areal difference of the mortality and of its decrease at present.<BR>5. The present are a l difference in the mortality from tuberculosis is, presumably, caused not only by the difference of the effects of the treatment and preventive measures after the War but also other factors before the introduction of chemotherapeutics. Those to be mentioned among all are the effect of the intensity of the epidemic before the War on the mortality for female and effect of the War excess on the mortality for male. It is emphasized that the historical aspect of the prevalen c e of tuberculosis should be taken into consideration to eliminate the areal difference of the mortality from tuberculosis.