ASPPH logo


Student & Alumni Achievements

Student & Alumni Achievements

Washington Student Finds High-fiber Laxatives Linked to Lower Risk of Colorectal Cancer

A study led by a University of Washington School of Public Health doctoral student found frequent use of fiber-based laxatives reduces the risk for colorectal cancer while use of non-fiber laxatives increases the risk.

Jessica Citronberg

[Photo: Ms. Jessica Citronberg (credit: Bo Jungmayer/Fred Hutch News Service)]

The study, published in The American Journal of Gastroenterology, was led by Ms. Jessica Citronberg, a third-year PhD student in epidemiology at the UW and a pre-doctoral fellow at the Fred Hutchinson Cancer Research Center in Seattle. About 20 percent of Americans use laxatives, and it had been hypothesized that they increased the risk of colorectal cancer.

Ms. Citronberg and colleagues at the center analyzed data from more than 75,000 men and women ages 50 to 76 in western Washington state. The participants were surveyed between 2000 and 2002 and followed until 2008; 558 were diagnosed with colorectal cancer.

The researchers found that those who used non-fiber laxatives (such as ex-lax or Milk of Magnesia) five or more times a year had a 43 percent increased risk of colorectal cancer. Those who used fiber-based laxatives (such as Metamucil) at least four days a week for four years had a 56 percent lower chance of the disease.

Researchers found no significant associations between bowel movement frequency or constipation and colon cancer risk. Study co-authors included Drs. Elizabeth Kantor, John Potter and Emily White.