[Relationship between colorectal cancer and ten inorganic elements].

A population-based case-control study including 726 patients with colon cancer, 575 with rectum cancer, and 1400 population controls matched on age (+/- 5 yrs.) and sex was carried out to evaluate the association of ten inorganic elements, including potassium, sodium, calcium, magnesium, iron, manganese, zinc, copper, phosphorus and selenium, and other dietary factors with colorectal cancer. Single variable analysis adjusted for age and sex showed most of the ten elements, except sodium and selenium, may reduce the risk of the development of colorectal cancer. Correlation analysis indicated these eight elements correlated closely to the "vegetable factors", e.g., dietary fibre, and so on, since the major sources (about 80%) of these elements were from vegetables. Multi-variable logistic regression analysis showed nine elements (except sodium) may confound the effects of some dietary factors (such as dietary fibre and vitamin C) on the occurrence of colorectal cancer and only contribute to it. The results showed a close association between saturated fatty acid, mono-unsaturated fatty acid, dietary fibre, vitamins C and E, and colorectal cancer.