Lighting Up May Be Hazardous to Your Colon
July 21, 2000 -- Here's one more reason to kick the habit -- researchers have determined that cigarette smoking increases the risk of getting colon cancer. Compared to people who have never lit up, smokers face nearly double the risk of developing colon cancer. And the more a person smokes, especially if they began at a young age, the higher the risk becomes.
"This risk also doesn't disappear once you quit," study author Robert J. Glynn, ScD, PhD tells WebMD. "It's not like in heart disease, where about a year or two after you stop smoking, the risk is like for a never smoker, but unfortunately, for this disease, the exposure lives on and continues throughout your life." Glynn is an associate professor of medicine in the division of preventative medicine at Brigham and Women's Hospital in Boston.
Previous research has reported an association between smoking and colon polyps. Between 70 and 90% of colon cancers arise from these polyps. But while smoking has been linked with these growths, the link between cigarettes and colon cancer has remained hazy.
Reporting their research in the current issue of the Journal of the National Cancer Institute, a team of Boston researchers decided to find out if that link exists. They followed more than 22,000 U.S. men who were in good health.
Based on data gleaned from questionnaires, the researchers found that men who currently smoked had nearly twice the risk of developing colon cancer, compared to those who had never smoked. For those who smoked at least a pack a day, the risk climbed even higher. And those that smoked the most and the longest had the highest risk of all. But even shorter term, casual smokers still had an increased risk of cancer.
"Quitting may diminish the risk, but not by much," Glynn says. "The damage has already been done, and some studies have said that there's no benefit to quitting, as far as diminishing your risk [of colon cancer]. The best thing is not to start, and the public health message of our paper is to let's work hard to keep kids from starting."
David Frank, PhD, MD, agrees. "It certainly strengthens the idea that one should be discouraged from smoking and that people should be discouraged from smoking early in their life," he tells WebMD. "That's one of the important factors here. The damage takes many decades to show up, so many people in their 20s think they can smoke and then stop and it's okay -- this is part of the evidence which shows that this isn't a good approach." Frank, who is an assistant professor of medicine at the Dana Farber Cancer Institute in Boston, was not involved in the study.