Bowel transit-time and stool weight in populations with different colon-cancer risks.

It has been suggested that the risk of cancer, polyposis, and diverticulosis of the large bowel increases with bowel transit-time. Hence, Japanese inhabitants of Hawaii, in whom the risk of these diseases is high, would be expected to have longer transit-times than Japanese in Japan, in whom such risks are low. However, bowel transit-times were similar in Japanese groups. Stools from the Hawaii Japanese did weight significantly less than the specimens from Japan, and this factor may be indirectly related to the risk of colorectal cancer, polyposis, or diverticulosis in the Japanese.