Having long-term constipation doesn’t raise the risk of colorectal cancer, a new study concludes. According to a March 21 Reuters report, while previous studies have indicated a connection between constipation and increased risk of colorectal cancer, a new analysis shows that’s not the case.
A team of researchers from Leeds Gastroenterology Institute of St. James's University in the UK reanalyzed data from 28 existing studies to determine if there is a connection between constipation and colorectal cancer. The data included information from more than 250,000 study participants from 1966 to 2011.
The author of the new analysis, Dr. Alexander Ford, said his team found little evidence to support the constipation-colorectal cancer connection. Their findings were published in the American Journal of Gastroenterology. The researchers said that previous study results might have been skewed by poor study design.
According to the Centers for Disease Control and Prevention, colorectal cancer is the second leading cause of cancer deaths in the United States. In 2009 — the latest year for which statistics are available — 136,717 people were diagnosed with colorectal cancer and 51,848 people died of it. Known risk factors for colorectal cancer are increasing age, inflammatory bowel disease, having a personal or family history of the disease, certain diseases that cause colon polyps, being overweight, and excessive alcohol consumption.
Previous studies have suggested that chronic constipation might also be a risk factor for colorectal cancer by causing prolonged contact between the lining of the colon and possibly carcinogenic substances in the stool.
But Ford and his team found little evidence to support that theory. They said that participants in previous studies were asked to remember their bouts with constipation, and that there was a high chance that they recalled details incorrectly. The researchers said that people who have chronic constipation alone and lack other risk factors are not at increased risk of colorectal cancer.
Ford said that both doctors and patients often worry that chronic constipation will lead to colorectal cancer. In its early stages, colorectal cancer has few if any symptoms. In later stages, colorectal cancer symptoms include blood in the stool, stomach pain or cramps, and unexplained weight loss, according to the CDC.