Obesity linked to colorectal cancer

Washington, Oct. 13: According to a recent study, women who are overweight or obese have up to twice the risk of developing colorectal cancer before age 50 in contrast to women who have what is considered a normal body mass index.

In the United States, overall rates of new colorectal cancer cases and deaths from the disease have decreased steadily since 1980, largely owing to recommended colonoscopy screening starting at age 50.

For reasons that remain unknown, new cases of, and deaths due to, both colon and rectal cancers have been increasing for younger adults ages 20 to 49. The study is among the first epidemiologic analyses of the potential contributors to early, onset colorectal cancer, cases diagnosed under age 50.

The researchers found that higher current BMI, BMI at 18 years of age, and weight gain since early adulthood are associated with increased risk of colorctal cancer under age 50.

The study included data from 85,256 women ages 25 to 44 in the Nurses’ Health Study II, which began in 1989. The researchers collected detailed information on body weight throughout the life course, family and endoscopy histories, and lifestyle factors at study baseline and every two to four years. Up to 2011, doctors diagnosed 114 colorectal cancer cases under age 50.

“Our findings really highlight the importance of maintaining a healthy weight, beginning in early adulthood for the prevention of early- onset colorectal cancer,” said cosenior author and cancer epidemiologist Yin Cao.

“We hypothesized that the obesity epidemic may partially contribute to this national and global concern,” Cao said.