It is now well-established that cancer is well-linked to smoking.
And now according to researchers, cigarettes increase the odds
for developing colon cancer, especially for women.
According to the new study, published April 30 in Cancer
Epidemiology, Biomarkers & Prevention, women who've ever
smoked have an almost 20 percent increased risk for colon cancer,
compared with women who never smoked.
"Women who smoke even 10 or fewer cigarettes a day increase their
risks for colon cancer," said lead researcher Dr. Inger Gram, a
professor in the department of community medicine at the
University of Tromso in Norway.
"Because colon cancer is such a common disease, even these
moderate smoking accounts for many new cases," she said. "A lot
of colon cancer can be prevented if people don't smoke -
More than 600,000 men and women ages 19 to 67 are involved in the
study whereas they were surveyed by the Norwegian Institute of
Public Health. Participants answered questions concerning their
smoking habits, physical activity and other lifestyle factors.
Over 14 years of follow-up nearly 4,000 people developed colon
cancer, and the odds were greatest for smokers, women in
particular according to Gram's team. The risk for colon cancer
increased 19 percent among women who smoked and 8 percent for men
who smoked, they added.
The researchers said, the more years a woman smoked, the earlier
she started smoking, and the more packs of cigarettes smoked a
year, the greater her risk of developing colon cancer. Women who
smoked for 40 years or more increased their risk for colon cancer
almost 50 percent, they added.
Gram noted, their risk was especially high for developing
proximal, or right-sided, colon cancer, with a type of tumor
specifically related to smoking.
Gram said she was surprised the link between smoking and colon
cancer was so much greater for women, and said the reasons aren't
Although this study shows an association between smoking and
colon cancer, it does not establish a cause-and-effect
relationship. However, the link between smoking and colon cancer
is more than a coincidence, Gram pointed out.
"Colon cancer is a smoking-related cancer," she said. "That has
recently been established by the International Agency for
Research on Cancer of the World Health Organization." Based on a
review of prior research, the WHO says long-term smoking appears
to double the risk of colon cancer. It also increases risk for
bladder and pancreatic cancer, according to the agency.
One expert, Dr. Stephanie Bernik, chief of surgical oncology at
Lenox Hill Hospital in New York City, doesn't believe the
heightened risk for colon cancer among women is solely related to
smoking. Alcohol use, diet and lack of exercise may also play a
role, Bernik said.
"Usually, smoking goes along with other bad health habits,"
Bernik said. "However, this adds to the growing data that
cigarette smoking contributes to the increased risk of colon
Another expert offered some advice. "If you smoke, you should
quit," said Dan Jacobsen, from the Center for Tobacco Control at
North Shore-LIJ Health System in Great Neck, N.Y. "There are a
lot of good methods, programs and resources out there if you want
to try to quit smoking," he added.
"Smoking is just toxic to our bodies," said Jacobsen. "It's the
number one preventable cause of death and disease."