The Influence of Sedentary Behavior on Cancer Risk: Epidemiologic Evidence and Potential Molecular Mechanisms

Abstract

Sedentary behavior is an emerging risk factor for several cancers. Here, we review the current epidemiologic evidence on sedentary behavior and cancer risk and summarize potential underlying molecular mechanisms. High compared to low sedentary behavior is associated with a 28-44% increased risk of colon cancer, a 8-17% increased risk of breast cancer, and a 28-36% increased risk of endometrial cancer. For other cancer sites, the current evidence is insufficient, mainly due to sparse numbers of available studies. Potential underlying biologic mechanisms linking prolonged sedentary behavior to increased cancer risk include metabolic dysfunction, alterations in circulating levels of sex hormones, and low-grade systemic chronic inflammation. Prolonged sedentary behavior is positively related to cancers of the colon, breast, and endometrium. For other cancer types, the current evidence is inconclusive. Underlying biological mechanisms are poorly understood and need to be an integral part of future research.