Obese people are six times as likely to develop gullet (oesophageal) cancer as people of ‘healthy’ weight, shows research conducted by the Queensland Institute of Medical Research and published ahead of print in the journal Gut.
Rates of oesophageal cancer have been rising rapidly, and in some countries, they have risen faster than those of every other major cancer, said QIMR’s Dr David Whiteman.
“Men and those under the age of 50 were especially at risk of oesophageal cancer,” said Dr Whiteman. “The link between acid reflux and gullet cancer is well known, and unsurprisingly, repeated symptoms of severe heartburn or gastrointestinal reflux disease (GORD) were associated with a much higher risk of the cancer.”
The more frequent the symptoms were, the higher the chance of having the disease.
GORD increased the risk of oesophageal cancer more than five-fold, and a combination of obesity and acid reflux boosted the chances of having it by a factor of 16.
However, people who were clinically obese had a much higher risk of oesophageal cancer than those whose weight was in the healthy range, regardless of whether they had reflux disease or not.
Those with a body mass index (BMI) of 40 or more were six times as likely to have gullet cancer as those with a BMI between 18.5 and 25.
This finding held true even after taking account other factors known to be implicated in the disease, such as smoking and high alcohol consumption.
“This suggests that obesity is an independent risk factor for the disease,” Dr Whiteman added.
Higher levels of fat tissue in the body boost insulin production, which in turn increases the amount of circulating insulin like growth factor.
Both these hormones stimulate cell growth and curb cell death, conditions which favour the development of cancers.
Fat cells also produce other hormones, collectively known as adipocytokines, which speed up cell growth and are involved in inflammatory processes in the body.
The findings are based on a comparison of almost 800 people with oesophageal cancer and almost 1,600 randomly selected people, who did not have the disease.