Strong Link Between Obesity And Colorectal Cancer
clear, direct link between obesity and colorectal cancer, the second
most common form of cancer in Australia with more than 12,000 new cases
each year, has been shown in a new analysis by The George Institute for
International Health in Sydney, Australia.
report shows that obese individuals (Body Mass Index* (BMI) >30
kg/m2) have a 20% greater risk of developing colorectal cancer compared
with those of normal weight (BMI < 25 kg/m2). The analyses also
indicated that obese men are at 30% greater risk of developing the
cancer compared with obese women. Findings from the study also showed
that carrying even a few excess kilos substantially increases the risk
of colorectal cancer; for every 5 kg weight gain the risk of developing
the cancer increases by 7%.
Rachel Huxley and co-authors at The George Institute reviewed over
70,000 patients in an analysis that included studies all across the
globe: "Approximately, one in twenty Australians will develop
colorectal cancer in their lifetime and our data clearly indicate that
the risk of developing the cancer can be substantially reduced by
maintaining a healthy weight" said Dr Huxley.
new report carries links with the latest report from the World Cancer
Research Fund Report, which provides further support regarding the link
between obesity and cancer. Importantly, the primary recommendation of
the report is; "Be as lean as possible within the normal range of body
weight", supported by a public health goal of 'Median adult body mass
index (BMI) to be between 21 and 23'. All eight recommendations made in
the report were focused on healthyeating, drinking and physical
activity, creating a sincere message of the relationship between diet
and cancer risk. "Although the mechanisms that explain the link between
excess weight and cancer remain to be elucidated, substantial evidence
supports an important role for diet and physical activity" added Dr
the international and George Institute report stress the increasing
levels of obesity in both high income and developing countries.
"Currently, around 300 million people across the world are obese. This
figure is expected to rise up toward 700 million by 2015. Considering
that obesity increases the threat of colorectal cancer by 20%, this
means that 10,000 cases each year are due to severe excess weight. The
number of cases of colorectal cancer alone, caused by obesity, is
likely rise to at least 25,000 by 2015," added Dr Huxley.
Mass Index (BMI) is measured by dividing your body weight in kilograms
by height in meters squared. An individual's BMI is associated with
their body fat and health risk, a high BMI is >30kg/m2 and normal
BMI is 25kg/m2."
authors conclude by stating, while 20% is a considerable risk, previous
reviews have suggested that obesity may be associated with up to 30-60%
greater risk of colorectal cancer. However, according to Dr Huxley,
"this over-estimation is most likely due to the impact of publication
bias in medical and scientific journals. Regardless, a 20% greater risk
is still considerable and sends a clear message about watching what you
eat and being more physically active."
This research was published in the journal Cancer Epidemiology, Biomarkers and Prevention.
*The BMI equation is = body weight in kilograms/height in meters squared.
For more information on the George Institute, visit www.thegeorgeinstitute.org.