In the Journals

Colorectal cancer risk decreased with fiber laxative use, increased with nonfiber laxatives

Use of fiber laxatives was associated with a decreased risk for colorectal cancer, while nonfiber laxative use was linked with an increased risk, according to recent study data.

Investigators prospectively evaluated 75,214 participants of the Vitamins and Lifestyle study in the state of Washington to determine associations between colorectal cancer (CRC) risk and laxative use. Participants completed questionnaires (2000 to 2002) regarding bowel movement frequency and average 10-year nonfiber laxative use, fiber laxative use and constipation. They also were followed up for CRC incidence through 2008, at which time there were 558 cases.

Participants who reported low (one to four times annually) or high (five or more times annually) use of nonfiber laxatives had 43% to 49% increased risk for CRC (HR=1.49; 95% CI, 1.04-2.14 and HR=1.43; 95% CI, 0.82-2.28, respectively) compared with those who used them less than once annually. CRC risk was lowest in participants who reported high-fiber laxative use for at least 4 days per week for at least 4 years (HR=0.44; 95% CI, 0.21-0.95) compared with those who never used them. Researchers said there was no decreased risk associated with low-fiber laxative use (HR=1.17; 95% CI, 0.82-1.68) and no associations between CRC risk and bowel movement frequency or constipation.

“We observed that nonfiber laxative use was associated with an increased risk for CRC, whereas fiber laxative use was inversely associated with risk,” the researchers wrote. “However, uncertainty remains about our findings because of lack of monotonic dose-response trends for our results, the possibility of residual confounding in observational epidemiologic studies, and lack of consistent support for our results from experimental studies.

“Thus, further research of specific laxative types is needed before conclusions can be drawn about recommending any specific type of laxative to patients with constipation.”

Disclosure: The researchers report no relevant financial disclosures.

Use of fiber laxatives was associated with a decreased risk for colorectal cancer, while nonfiber laxative use was linked with an increased risk, according to recent study data.

Investigators prospectively evaluated 75,214 participants of the Vitamins and Lifestyle study in the state of Washington to determine associations between colorectal cancer (CRC) risk and laxative use. Participants completed questionnaires (2000 to 2002) regarding bowel movement frequency and average 10-year nonfiber laxative use, fiber laxative use and constipation. They also were followed up for CRC incidence through 2008, at which time there were 558 cases.

Participants who reported low (one to four times annually) or high (five or more times annually) use of nonfiber laxatives had 43% to 49% increased risk for CRC (HR=1.49; 95% CI, 1.04-2.14 and HR=1.43; 95% CI, 0.82-2.28, respectively) compared with those who used them less than once annually. CRC risk was lowest in participants who reported high-fiber laxative use for at least 4 days per week for at least 4 years (HR=0.44; 95% CI, 0.21-0.95) compared with those who never used them. Researchers said there was no decreased risk associated with low-fiber laxative use (HR=1.17; 95% CI, 0.82-1.68) and no associations between CRC risk and bowel movement frequency or constipation.

“We observed that nonfiber laxative use was associated with an increased risk for CRC, whereas fiber laxative use was inversely associated with risk,” the researchers wrote. “However, uncertainty remains about our findings because of lack of monotonic dose-response trends for our results, the possibility of residual confounding in observational epidemiologic studies, and lack of consistent support for our results from experimental studies.

“Thus, further research of specific laxative types is needed before conclusions can be drawn about recommending any specific type of laxative to patients with constipation.”

Disclosure: The researchers report no relevant financial disclosures.