A new European study shows that being obese or even overweight may
increase a person's risk of developing up to a dozen different
types of cancer, media reported Friday.
The study suggests that weight gain could not only increase
chances for colon and breast cancers as doctors previously
suspected, but also for cancer of the esophagus, thyroid, kidney,
uterus and gall bladder.
More than 280,000 subjects, both overweight and normal weight,
from North America, Europe, Australia and Asia were followed for
about nine to 15 years, with researchers tracking their body mass
index and correlating it with incidents of cancer.
In men, an average weight gain of 15 kg (33 pounds) increased
the risk of esophageal cancer by 52 percent, thyroid cancer by 33
percent, and colon and kidney cancers each by 24 percent. In women,
a weight gain of 13kg (29 pounds) increased the risk of cancer in
the uterus and gall bladder by nearly 60 percent, esophagus by 51
percent and kidney by 34 percent.
While the study suggests a link, there is no definitive proof
that being fat in itself causes cancer. One of the hypotheses is
that the presence of excess fat cells could affect the levels of
hormones in the body, which may favor the development of tumors in
humans.
"To make the link between cause and effect, we need to tick
several boxes," said Dr. Andrew Renehan, the study's lead author
and senior lecturer at the School of Cancer Studies at the
University of Manchester. "This study begins to tick the first two
or three boxes, but more research is needed to confirm it."
"The simple message is that, if you manage to keep a healthy
body weight, you will have a lower risk of developing cancer," said
Ed Yong of Cancer Research United Kingdom.
(Xinhua News Agency February 15, 2008)
