[A case-control study of colorectal cancer in Beijing].

A case-control study was conducted among 250 persons suffering from cancer of the colon and rectum (CRC) in the urban area of Beijing from Jan 1, 1988-June 30, 1989 to explore the risk factors for CRC. 500 neighbour residents were matched as control. The chi-square test and conditional logistic Regression analysis show that high consumption of meat, oil, low occupational physical activity and psychological stress were risk factors of CRC. A trend of increased odds ratio (OR) of CRC with high meat intake and a trend of decreased OR with increased occupational physical activity were found. The high consumption of vegetables and the habit of eating uncooked fresh vegetables showed a protective effect on CRC. The results of the study support the CRC etiological hypotheses of "fat-bile acid action" and "deficiency of dietary fibres".