Colorectal cancer risk rises with obesity

Related tags Obesity

As the food industry collaborates with the European Commission on
efforts to slash soaring rates of obesity, a new study compounds
the need for change, linking the condition with an increased risk
of developing colorectal and oesophageal cancers, reports
Lindsey Partos.

Fresh figures released in March show in excess of 200 million adults across the EU may be overweight or obese.

And the number of European kids overweight is rising by a hefty 400,000 a year, according to data from the International Obesity Task Force (IOFT).

A key concern for governments footing the healthcare bills is that obesity, defined as a Body Mass Index over 30, is a risk factor for a host of (expensive) illnesses including heart disease, hypertension and respiratory disease. According to the European Commission, obesity accounts for between 2 to 8 per cent of healthcare costs in Europe.

According to new research presented this week at Digestive Disease Week 2005 (DDW) in the US, recent studies show that losing weight may decrease the chances of developing colorectal adenoma.

High risk lifestyle behaviours have been associated with an increased incidence of colorectal neoplasm.

Researchers at the University of Tokyo conducted a two-fold study to evaluate the effects of high body mass index (BMI) on the risk of colorectal adenoma and if weight reduction reduced the prevalence of this condition.

The results show that obesity is positively associated with increased risk of colorectal adenoma, and that weight reduction significantly decreases a patient's risk for developing the condition.

In addition, colonoscopy results were analysed for 8,788 asymptomatic patients who had no colorectal tumours or whose tumours could be endoscopically removed.

Patients were classified into one of four groups based on BMI and their colonoscopy results were analysed.

Of the 8,788 patients included in the study, 2,819 underwent a second colonoscopy after one year to evaluate the effect of weight loss on colorectal adenoma diagnosis.

In the study, 1,817 of the subjects initially examined were found to have colorectal adenomas at the initial diagnosis, with the highest BMI groups having the most occurrences of colorectal adenoma.

Comparing between individuals who had achieved a five per cent or more reduction in their body weight to those who did not, of the 2,819 patients who underwent a second colonoscopy one year later, patients in the weight reduction group significantly reduced their incidence of colorectal adenoma; at 10.9 per cent compared to 17.3 per cent for patients who did not lose weight.

"Our study illustrates the importance of maintaining a healthy body weight in the prevention of colorectal adenoma,"​ said Yutaka Yamaji, lead study author from the University of Tokyo. "Patients who lower their BMI may reduce their risk of developing colorectal cancer in the future."

In the second study, researchers at Queen's University Belfast in Ireland examined the possible link between BMI, smoking and Barrett's Esophagus (BE) in conjunction with esophageal cancer, a disorder which causes the lining of the oesophagus to become damaged as a result of irritation from stomach acid leakage.

They found that although BMI and cigarette smoking are linked to oesophageal cancer, they are not associated with BE.

The researchers suggest that BMI and smoking may play a key role in the progression of Barrett's Esophagus to esophageal cancer, but not in the initial development of Barrett's Esophagus.

The Irish scientists gave questionnaires to 662 patients to obtain information regarding patients' BMI five years prior to the study interview date, BMI at age 21 and smoking history.

The study population included 200 patients with a severe form of BE called long segment BE, 234 patients with esophageal adenocarcinoma and 228 control patients.

Researchers found that patients with BE did not report a higher BMI than normal controls five years prior to the interview date or at age 21, showing no link between higher BMI and BE.

"There was also no correlation established between smoking and BE,"​ report the researchers.

Conversely, patients with oesophageal cancer were more likely than controls to report a higher BMI five years prior to the study interview date.

In addition, patients with EAC were twice as likely to have been ex-smokers and four times as likely to be current smokers when compared to the normal control group.

"Although there is not an established link among smoking, BMI and Barrett's esophagus, patients suffering from BE should avoid a high BMI and smoking to prevent the development of esophageal cancer,"​ said Liam Murray, at Queen's Belfast University, and a senior author of the study.

"However, all patients should consider maintaining a healthy weight and smoking cessation to reduce their risk of developing esophageal cancer and other major GI tract disorders,"​ he concludes.

The European food industry was recently plucked out by Brussels to participate in a new platform that brings industry, consumer groups, health experts and political leaders together to discuss voluntary actions to combat obesity.

For the moment, self-regulatory notions will guide discussions. Food industry fears that the Commission might eventually draw up legislation proposals for food, particularly on labelling and advertising, may not be realised, at least not for now.

"My preference is not to have to regulate,"​ the health and consumer protection Commissioner Markos Kyprianou told the press conference at the launch of the platform.

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