In this study, physicians from Japan examined the relationship between bowel movement (BM) frequency and the risk of colorectal cancer.
The team assessed 25,731 men and 37,198 women from 24 communities in Japan.
Participants completed a self-administrated questionnaire on BM frequency and laxative use.
The team calculated incidence rate ratios (IRR) with 95% confidence intervals (CI) using Cox's proportional-hazard model.
|There was no association between cancer risk and laxative use.|
|British Journal of Cancer|
During the mean 7.6 year follow-up period, the physicians identified 649 cases of colorectal cancer. Of these, 429 cases were colon cancer.
The team found that women who reported a BM every 2 to 3 days had the lowest risk of developing colorectal (IRR=0.71) and colon cancer (IRR=0.7), compared with those reporting 1 BM per day.
In addition, women reporting a BM every 6 days or less, had an increased risk of developing colorectal (IRR=2.47) and colon cancer (IRR=2.52).
The physicians identified a similar association in men, but this was not statistically significant.
There was no association between colorectal or colon cancer risk and laxative use.
Dr Kojima and colleagues concluded, "Regulating BM frequency might therefore have a role in the prevention of colorectal cancer".