[A comparative case-control study of stomach and large intestinal cancers]

The incidence of stomach cancer, the most common cancer in Japan, has been decreasing, but that of colon cancer has been increasing in recent years. It is assumed that the change of Japanese life style, in particular dietary habits, has influenced the time trends of these gastro-intestinal cancers. In order to identify common, inverse and independent risk factors for the two contrasting cancers, a simultaneous comparative case-control study of both sites of cancers was done using a common questionnaire at the Aichi Cancer Center Hospital in 1981-1984. Its main results suggested that typical Japanese foods were positively associated with stomach cancer whereas western style foods increased the risk of colon cancer but decreased the risk of stomach cancer. It was suggested that a simultaneous comparative case-control study could be useful in identifying common, inverse or independent risk factors for the two contrasting cancers, such as stomach and colon cancers.