Does Constipation Increase Your Risk of Colon Cancer?

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If you deal with constipation on a chronic basis, you may harbor understandable concerns as to whether such infrequent bowel movements might raise your risk of developing colon cancer. Seems like a relatively simple question, doesn't it? Unfortunately, the answer is far from simple. Read on to see what is currently known about any possible connection between chronic constipation and colon cancer risk.

Prevalence Rates of Constipation and Colon Cancer

If you experience chronic constipation, you are far from alone. Worldwide, it is estimated that approximately 14% or all people deal with constipation on a regular basis. Your risk goes up if you are female, and your risk goes way up if you are over the age of 65 (25%!).

Your lifetime risk of developing colorectal cancer is about 1 out of 20, making it the fourth most common type of cancer in the U.S. In terms of cancer-related deaths, in the U.S., colorectal cancer comes up second on the list. Luckily, the number of people who die from colorectal cancer is decreasing year after year. This is attributed to increased screening and improved treatments.

Why Might There Be an Association Between Constipation and Cancer?

Researchers theorize that chronic constipation may raise one's risk of developing colorectal cancer for two reasons:

1. Chronic constipation may cause the number of carcinogens in the stool, (such as bile acids and other compounds), to become more concentrated.

2. Chronic constipation may result in these carcinogens being in contact with the cells lining the large intestine and rectum for longer periods of time.

Conflicting Research Results

Many large- and small-scale clinical studies have been conducted to assess whether or not chronic constipation raises a person's risk for colorectal cancer.

Study results have been conflicting, with some studies concluding that there is a risk, and other studies concluding that there is no such risk. Some studies have even shown that chronic constipation can decrease the risk!

Why do study results vary so widely? There are a couple of reasons:

1. Many of the studies that have found no risk are case-control studies - studies in which people who end up with cancer are compared to those who don't. The problem with this type of study is that the results can be biased - in other words, people who are diagnosed with colon cancer may be biased to recall that they did experience constipation on a regular basis.

2. The possibility that it is not constipation that raises the risk for cancer, but that the risk is raised due to the use of laxatives.

A comprehensive meta-analysis (a study that combines data from multiple studies) concluded that studies that are not case-control studies, in other words that do not run the risk of recall bias, as a whole offer evidence that there is no increase in the rates of colon cancer in people who experience chronic constipation.

There was one large study that provided some evidence that there is a connection between the severity of the constipation problem and an increased risk of colorectal cancer over time.

Interestingly, this increased risk was not seen in those patients with severe constipation who had been seen by a gastroenterologist or those who received a prescription for a laxative. The researchers conclude that perhaps efforts to directly address the problem of constipation may reduce one's risk.

Laxatives and Cancer Risk

Research study results have been just as mixed regarding an increased risk of colon cancer in people who use laxatives on a regular basis. It is thought that some of these mixed results occur because studies do not separate out the type of laxative used. A study in which risks were assessed based on the type of laxative used found a slightly higher risk of colon cancer in individuals who used non-fiber type laxatives.

Conversely, those who used "fiber laxatives", otherwise known as bulk laxatives or fiber supplements, had a decreased risk of developing colon cancer.

How to Decrease Your Risk

What is one to make of all of this conflicting information? It may bring some peace of mind to know that research is not finding a clear-cut strong connection between chronic constipation and colon cancer. It is possible that there is some increased risk, but that this risk may be reduced by working with a gastroenterologist on a treatment plan and/or using fiber supplements to ease your constipation symptoms. Certainly following your doctor's advice regarding when to undergo screening for colon cancer can also reduce your risk.

Eating a high-fiber diet and exercising regularly are two other things that can reduce your risk of colon cancer and perhaps may also be beneficial for your chronic constipation. 


Citronberg, J., et. al. "A prospective study of bowel movement frequency, constipation, and laxative use on colorectal cancer risk" American Journal of Gastroenterology 2014 109:1640–1649.

Guérin, A., et. al. "Risk of developing colorectal cancer and benign colorectal neoplasm in patients with chronic constipation" Alimentary Pharmacology & Therapeutics 2014 40:83–92.

"Key statistics for colorectal cancer" American Cancer Society website Accessed March 7, 2016.

Power, A., Talley, N. & Ford, A. "Association Between Constipation and Colorectal Cancer: Systematic Review and Meta-Analysis of Observational Studies" The American Journal of Gastroenterology 2013 108:894-903.