胃癌の疫学

THE EPIDEMIOLOGY OF CANCER OF THE STOMACH

Ⅰ．はじめに

　胃癌の発生原因を，疫学的に探究していくと，食生活パターンとの密接な関係に到達する．どのようなプロセスで，そのような関連性がみつかってくるか．その事実を踏まえてこれからどのように研究を発展させていくべきか，それらを成績の紹介と同時に，方法論に触れながら述べてみる．

1) An exceedingly high frequency of stomach cancer was noted in mortality, morbidity, autopsy and mass-X-ray screening statistics in Japan.

2) All of the observed epidemiologic phenomena suggest a significant effect of environ mental factors which probably operate more strongly in males, stronger in Japanese and Koreans than in Chinese or in Caucasians, stronger in lower socio-econornic strata and stronger in the northern part of Japan. The decreasing trend in recent years also indicates the strong effect of post-war environmental change.

3) Factors influencing the occurrence of stomach care were analysed by correlation studies, controlled case studies, and population prospecive studies.

4) The closest association with stomach cancer was observed between a) the lesser fregnency of milk intake and b) the excess intake of salty pickles, especially when study groups were compared to multiple-matched controls. The cross-tabulation of milk intake and intake of pickles showed that there factors were mutually independent in their association with stomach cancer.

5) The improvement of diet pattern, especially the increase of milk consumption should be encouraged. This could be cousidered as an experimental epidemiology.