Geographical studies of seasonality in cancer of the stomach

The purpose of this paper is to adduce pointers towards the underlying aetiology of cancer. Seasonal patterns of stomach cancer mortality were regionally and chronologically examined. Japan was considered at a national level. Two Tohoku regions (the Pacific facing and the Sea of Japan sub-regions). the Kansai region and the Kyushu region of Japan were chosen within Japan. At an international scale, Japan. England and Wales and the United States were compared. The following results were obtained: (1) A small autumn peak appeared throughout Japan. (2) There was no regional difference among the four Japanese regions. All of these regions had a small autumn peak. (3) In England and Wales and the United States there was hardly any variation of mortality between the seasons. Japan seemed to be showing a similar trend. On the basis of the above results some environmental factors were suggested as contributing to the seasonal pattern of stomach cancer.