Couch Potatoes May Have Increased Cancer Risk

Sedentary time associated with increased risk of colorectal and other cancers

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Between computer, TV and relaxation time, people spend more time sitting than ever before. And being a couch potato may raise your cancer risk.

A recent study found that people who spent several hours a day sitting or watching TV faced a higher risk for some types of cancer.

"Instead of watching TV, walk or jog around the block."

A group of researchers reviewed 17 past studies to collect information on the effects of inactivity on cancer risk. The studies included data on 857,581 people.

The study was written by Dong Shen, MD, of Southeast University Medical College in Jiangyin, China, and colleagues.

Sedentary behavior was defined as spending time sitting. In most studies, over three hours of time spent watching TV or sitting was considered sedentary.

The results showed that being sedentary was associated with a 20 percent increased overall cancer risk.

Sedentary patients had the highest increase in risk for colorectal cancer (30 percent) — followed by endometrial cancer of the uterus (28 percent), lung cancer (27 percent) and breast cancer (17 percent) — compared to people who were active.

The study authors found no association between inactivity and increased risk of ovarian, kidney renal cell cancer or non-Hodgkin lymphatic cancer.

"Public health guidelines for prevention and control of incident cancer may need to consider recommendations about reducing time spent sitting in addition to increasing [moderate to vigorous physical activity]," the authors wrote.

The authors noted that sedentary behavior was measured only at the start of most studies and may have changed during the study periods.

The review was published in the August issue of PLOS One.

The Medical Research Council and the British Heart Foundation partly funded the study. The authors declared no conflicts of interest.

Review Date: 
September 4, 2014
Last Updated:
September 4, 2014