Sedentary behavior is emerging as an independent risk factor for chronic disease and mortality. However, the evidence relating television (TV) viewing and other sedentary behaviors to cancer risk has not been quantitatively summarized.
We performed a comprehensive electronic literature search in Cochrane, EMBASE, Medline, and SciSearch databases through February 2014 for published articles investigating sedentary behavior in relation to cancer incidence.
Data from 43 observational studies including a total of 68936 cancer cases were analyzed.
- The relative risks (RRs) for colon cancer were 1.54 for TV viewing time, 1.24 for occupational sitting time, and 1.24 for total sitting time.
- For endometrial cancer, the relative risks were 1.66 for TV viewing time and 1.32 for total sitting time.
- A positive association with overall sedentary behavior was also noted for lung cancer.
- Sedentary behavior was unrelated to cancers of the breast, rectum, ovaries, prostate, stomach, esophagus, testes, renal cell, and non-Hodgkin lymphoma.
Prolonged TV viewing and time spent in other sedentary pursuits is associated with increased risks of certain types of cancer.