Women Smokers May Have Greater Risk for Colon Cancer Than Men
Researchers find 19% vs. 8% increased risk in females and males (Apr. 30)
Smoking increases the risk for developing colon cancer, and female smokers may have a greater risk than male smokers, according to new data published in Cancer Epidemiology, Biomarkers, and Prevention, a journal of the American Association for Cancer Research (AACR).
“Globally, during the last 50 years, the number of new colon cancer cases per year has exploded for both men and women,” said Inger Torhild Gram, MD, PhD, a professor at the University of Tromsø in Norway. “Our study is the first that shows women who smoke less than men still get more colon cancer.”
Gram and her colleagues examined the association between cigarette smoking and colon cancer in more than 600,000 Norwegian men and women. The participants underwent a short health examination and completed questionnaires about smoking habits, physical activity, and other lifestyle factors. They were then followed by linkage to the Cancer Registry of Norway and to the Central Population Register. During an average 14 years of follow-up, nearly 4,000 new cases of colon cancer were diagnosed.
The researchers found that female smokers had a 19% increased risk compared with never-smokers, whereas male smokers had an 8% increased risk.
In addition, women who started smoking when they were 16 years old or younger and women who had smoked for 40 years or more had a substantially increased risk, by about 50%. Further, the dose-response association between the number of cigarettes smoked per day, the number of years smoked, and the number of pack–years smoked and the risk of colon cancer was stronger for women than it was for men.
“The finding that women who smoke even a moderate number of cigarettes daily have an increased risk for colon cancer will account for a substantial number of new cases because colon cancer is such a common disease,” said Gram. “A causal relationship between smoking and colorectal cancer has recently been established by the International Agency for Research on Cancer of the World Health Organization, but, unfortunately, this is not yet common knowledge, neither among health personnel nor the public.”
Source: AACR; April 30, 2013.