A new study, led out by Dr. Michael J. Thun, Vice President Emeritus, Epidemiology and Surveillance Research at the American Cancer Society, has revealed that there is a definite link between smoking and developing colorectal cancer.

Despite adjusting their own risk factors, people who smoke expose themselves to an increase risk of contracting colon cancer. "This provides one more reason not to smoke, or to quit as soon as possible. Colorectal cancer should be added to the list of cancers caused by smoking", said Dr. Thun.

For the sake of research, nearly 185,000 subjects, between the ages of 50 and 74, were followed from 1992 to 2005, and their behavior and lifestyle habits were noted. An analysis of data collected signified that those who had smoked for 40 years or more had a 30-50% increased risk of contracting colon cancer. The analysis bordered on the same figures even when all potential risk factors were adjusted.

Another study has some more bad news for people who have not decided to quit yet, or live in regular contact with heavy smokers. Passive smoking has also been linked to raising a woman's chances of contracting breast cancer, and also to a child's lifetime risk for lung cancer.

Both the studies have been published in detail in the December issue of the Cancer Epidemiology, Biomarkers & Prevention journal.