Bowel movement, use of laxatives and risk of colorectal adenomatous polyps among women (United States).
BACKGROUND
Infrequent bowel movements and use of laxatives have been hypothesized to increase risk of colorectal neoplasia. However, the few existing epidemiologic studies in humans have been inconclusive.


OBJECTIVE
To investigate prospectively the associations of bowel movement frequency and laxative use with the occurrence of adenomatous colorectal polyps in women.


METHODS
A total of 17,400 women 36-61 years of age, without previous diagnosis of cancer or polyps, responded to a mailed questionnaire in 1982 that assessed bowel movement frequency and use of laxatives and had an endoscopy between 1984 and 1996. Between 1984 and 1996, 906 cases of adenomatous polyps (496 classified as small (< 1 cm), 358 classified as large (> or = 1 cm) and 52 unclassified) were documented. Relative risks (RRs) of adenomas and 95% confidence intervals (CIs) were calculated using logistic regression.


RESULTS
After controlling for adenoma risk factors, the multivariate RRs associated with having bowel movements every third day or less compared to once daily were 0.9 (95% CI: 0.7-1.2) for total colorectal adenomas, 1.0 (95% CI: 0.7-1.5) for large adenomas and 1.0 (95% CI: 0.7-1.3) for adenomas of the colon only. The multivariate RRs associated with weekly to daily laxative use compared to never use were 0.9 (95% CI: 0.7-1.1) for total colorectal adenomatous polyps, 1.0 (95% CI: 0.7-1.5) for large adenomas and 0.8 (95% CI: 0.6-1.2) for colon adenomatous polyps only.


CONCLUSIONS
These findings do not support an association between infrequent bowel movement or laxative use and risk of colorectal adenomas.
Dukas
L
L
Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA.
Platz
E A
EA
Colditz
G A
GA
Willet
W C
WC
Giovannucci
E L
EL
D018256:Adenomatous Polyps / Q000453:epidemiology / Q000209:etiology*; D000328:Adult; D002400:Cathartics / Q000009:adverse effects*; D003111:Colonic Polyps / Q000453:epidemiology / Q000209:etiology*; D003672:Defecation; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
D002400:Cathartics