Long-term constipation doesn't raise risk for colon and rectal cancers according to a new analysis of the existing evidence.
Past studies had suggested a possible connection, but researchers said those results may have been skewed by poor study designs.
"Someone who's got chronic constipation is unlikely to be associated with colon cancer now or in the future," said study author Dr. Alexander Ford, senior lecturer at the St. James's University Hospital's Leeds Gastroenterology Institute in the UK.
Colorectal cancer is the second leading cause of cancer death in the U.S., with an estimated 51,000 Americans dying from it each year, according to the Centers for Disease Control and Prevention.
Established risk factors for the disease include a personal or family history of colorectal cancer, irritable bowel disease, certain syndromes that cause colon polyps, type 2 diabetes, obesity, heavy drinking, smoking and being over age 50, according to the American Cancer Society.