Obesity, Lack of Physical Exercise Increase Risk for Colorectal Cancer

A latest study conducted by researchers at the Dana Farber Cancer Institute has shown an alarming association between increasing body mass index and higher risk for colorectal cancer.

Prior to this, a study was conducted which linked physical activity to a reduced risk of the same cancer. But not much is known about this association and why it works.

In the current study, however, the researchers use a biomarker called CTNNB1 which is a molecule occupied in cancer and obesity.

In order to prove their hypothesis, the researchers worked on data that consisted of more than 100,000 women and more than 45,000 men who were a part of the Health Professionals study. The data collection started in 1976 for women and in 1986 for men.

The follow-up was completed in 2004, with nearly 2,263 cases of colorectal cancer detected; of which nearly 842 men and 1,421 women had been diagnosed with this cancer. Nearly 861 cases were of colorectal cancer. Nearly 54 percent were CTNNB1-negative and 48 percent were positive for the biomarker.

They noticed that higher the person's BMI, greater the chances of developing CTNNB1 negative colorectal cancer. If the BMI increased by 5 kg/m2 there was a 34 percent higher risk for CTNNB1-negative colorectal cancer. And increase in physical activity was linked to a drop in the CTNNB1-negative cancer.

"Our results provide additional evidence for a causal role of obesity and a physically inactive lifestyle in a specific molecular subtype of colorectal cancer," Dr. Shuji Ogino, an associate professor of pathology at Dana-Farber Cancer Institute and an associate professor in the department of epidemiology at Harvard School of Public Health, said in a news release.

The American Cancer Society states that nearly 102,480 new cases of colon cancer and 40,340 cases of rectal cancer will be diagnosed this year. And nearly 50,830 people will die as a result of suffering from colorectal cancer, reports LiveScience.

The study was published in the journal Cancer Research.