Dietary risk factors for cancer and adenomas of the large intestine. A case-control study within a screening trial in Denmark.

The aims of the study were to estimate the importance of dietary habits for colorectal cancers and adenomas. By comparing risk factors among cancer and adenoma patients the adenoma cancer theory was indirectly evaluated. The study was performed as a case-control study within a large screening trial in Denmark. All cancer and adenoma patients diagnosed at the screening were recruited as cases; controls were selected among test negatives after matching for age, sex and time of screening. All those selected except 85, participated in a 7-day dietary recall. Altogether 49 colorectal cancer patients and 172 with adenomas were examined; 362 individuals who were test negatives in the Hemoccult-II screen served as controls. The intake of crude dietary fibres was shown to be associated with reduced risk of cancer as well as adenomas. Neither cancer nor adenoma occurrences were related to total energy intake or body mass. Vitamins E and A were negatively associated with adenoma occurrence.