Obesity Strongest Risk Factor For Colorectal Cancer Among Women; Greater Than Smoking

Joseph C. Anderson, MD of Stony Brook University in New York (and the University of Connecticut) and his colleagues examined data from 1,252 women who underwent colonoscopy. They classified patients according to their age, smoking history, family history of colorectal cancer, and body mass index (BMI). Obesity was defined as a BMI of 30 or higher. For smoking, patients were divided into three groups: heavy exposure, low exposure, and no exposure. Patients who were in the heavy exposure group included women who had smoked more than 10 "pack years" and who were currently smoking or had quit in the past 10 years.

Although smoking posed a significant increased risk for colorectal neoplasia, researchers found that for women, obesity was the highest attributable risk factor for developing the disease. BMI accounted for one-fifth of all significant polyps detected during colonoscopy. Of those patients who had colorectal neoplasia, 20 percent were obese and 14 percent were smokers.

"Given the increasing number of obese patients in the U.S., identifying them as high risk may have important screening implications," said Dr. Anderson. "While obesity is positively associated with an increased risk of colorectal cancer, patients who lower their BMI could potentially reduce their risk of developing the disease in the future."

About Body Mass Index

Body mass index, or BMI, is a measurement that determines the healthiness of a person's weight. The formula is related to the amount of fat a person carries and is calculated using the person's height and weight. A healthy BMI is between 18.5 and 24.9. People are considered underweight if their BMI is less than 18.5, overweight if their BMI is between 25 and 29.9, and obese if their BMI is 30 or higher.