Obesity appears to be associated with an increased risk of developing colorectal and esophageal cancers.
Studies also show that losing weight may decrease the chances of developing colorectal adenoma.

Effect of body weight reduction on incidence of colorectal adenoma

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

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 colorectal adenoma.

Colonoscopy results were analyzed for 8,788 asymptomatic patients who had no colorectal tumors or whose tumors could be endoscopically removed.

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

The incidence of colorectal adenoma was compared between individuals who had achieved a five percent or more reduction in their body weight to those who did not.

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.

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 percent compared to 17.3 percent for patients who did not have a reduction in 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.”

Obesity and smoking in patients with Barrett’s esophagus and esophageal adenocarcinoma

Esophageal adenocarcinoma has been linked to high body mass index ( BMI ), a history of smoking and Barrett’s esophagus ( BE ), a disorder which causes the lining of the esophagus to become damaged as a result of irritation from stomach acid leakage.

However, the relationship between BMI, smoking and Barrett’s esophagus has been unclear.

Researchers at the Queen’s University Belfast in Ireland examined the possible correlation between BMI, smoking and Barrett’s esophagus in conjunction with esophageal cancer and found that although BMI and cigarette smoking are linked to esophageal cancer, but they are not associated with BE.
Therefore, 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.

Researchers administered 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 Barrett’s esophagus, 234 patients with esophageal adenocarcinoma and 228 control patients.

Researchers found that patients with Barrett’s esophagus 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 Barrett’s esophagus.

There was also no correlation established between smoking and Barrett’s esophagus.

Conversely, patients with esophageal 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, of 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.”

Source: Digestive Disease Week ( DDW ), 2005


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