Calling All Couch Potatoes: You Might Be at Risk for this Disease

By Sondra Forsyth

Here’s yet another compelling reason to get up off the couch: Physical inactivity can increase the risk of colon, endometrial, and lung cancers

This according to a study published in the Journal of the National Cancer Institute. When the highest levels of sedentary behavior were compared to the lowest, the researchers found a statistically significant higher risk for three types of cancer—colon, endometrial, and lung. Moreover, the risk increased with each two-hour increase in sitting time: 8% for colon cancer;  10% for endometrial cancer; and 6% for lung cancer

The effect also seemed to be independent of physical activity, suggesting that large amounts of time spent sitting can still be detrimental to those who are otherwise physically active.

Time spent watching TV was especially predictive of increased cancer risk.

TV viewing time showed the strongest relationship with colon and endometrial cancer, possibly, the authors write, because TV watching is often associated with drinking sweetened beverages, and eating junk foods.

In order to assess the relationship between TV viewing time, recreational sitting time, occupational sitting time, and total sitting time with the risk of various cancers, Daniela Schmid, Ph.D., M.Sc., and Michael F. Leitzmann, M.D., Dr.P.H., of the Department of Epidemiology and Preventive Medicine, University of Regensburg, Germany, conducted a meta-analysis of 43 observational studies, including over 4 million people and 68,936 cancer cases. Data in the individual studies had been obtained with self-administered questionnaires and through interviews.

The researchers wrote: “That sedentariness has a detrimental impact on cancer even among physically active persons implies that limiting the time spent sedentary may play an important role in preventing cancer….” In an accompanying editorial, Lin Yang and Graham A. Colditz, M.D., Dr.P.H., of the Siteman Cancer Center and Department of Surgery, Washington University School of Medicine, St. Louis MO, wrote that these results “…support a causal relation between sedentary behavior and both colon and endometrial cancers.”

So couch potatoes beware!