Cancer of the colon and rectum in the coloured population of Johannesburg. Relationship to diet and bowel habits.

In the Coloured population of Johannesburg, the incidence of carcinoma of the colon and rectum estimated over an 11-year period (1970-1980) is 1,33 and 1,08/100 000 respectively per year. This is lower than the incidence reported in Whites and appears to be even lower than that reported in South African and Zimbabwean Blacks. A survey of dietary factors in this population showed a diet which was high in protein, low in fats and high in bulk. The frequency of bowel action was higher than in both Whites and Blacks. These factors support Burkitt's hypothesis which states that races with a high-bulk diet have a lower incidence of large-bowel cancer.