title: Sedentary behavior and incident cancer: a meta-analysis of prospective studies.
abstract: BACKGROUND
  Sedentary behavior is ubiquitous in modern adults' daily lives and it has been suggested to be associated with incident cancer. However, the results have been inconsistent. In this study, we performed a systematic review and meta-analysis of prospective cohort studies to clarify the association between sedentary behavior and incident cancer.
  
  
  METHODS
  PubMed and Embase databases were searched up to March 2014. All prospective cohort studies on the association between sedentary behavior and incident cancer were included. The summary relative risks (RRs) with 95% confidence intervals (CIs) were estimated using random effect model.
  
  
  RESULTS
  A total of 17 prospective studies from 14 articles, including a total of 857,581 participants and 18,553 cases, were included in the analysis for sedentary behavior and risk of incident cancer. The overall meta-analysis suggested that sedentary behavior increased risk of cancer (RR = 1.20, 95%CI = 1.12-1.28), with no evidence of heterogeneity between studies (I(2) = 7.3%, P = 0.368). Subgroup analyses demonstrated that there were statistical associations between sedentary behavior and some cancer types (endometrial cancer: RR = 1.28, 95% CI = 1.08-1.53; colorectal cancer: RR = 1.30, 95%CI = 1.12-1.49; breast cancer: RR = 1.17, 95%CI = 1.03-1.33; lung cancer: RR = 1.27, 95%CI = 1.06-1.52). However, there was no association of sedentary behavior with ovarian cancer (RR = 1.26, 95%CI = 0.87-1.82), renal cell carcinoma (RR = 1.11, 95%CI = 0.87-1.41) or non-Hodgkin lymphoid neoplasms (RR = 1.09, 95%CI = 0.82-1.43).
  
  
  CONCLUSIONS
  The present meta-analysis suggested that prolonged sedentary behavior was independently associated with an increased risk of incident endometrial, colorectal, breast, and lung cancers, but not with ovarian cancer, renal cell carcinoma or non-Hodgkin lymphoid neoplasms.
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Shen
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Mao
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Lin
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Oncology, The Affiliated Jiangyin Hospital of Southeast University Medical College, Jiangyin, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway; MRC Epidemiology Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
authors.affiliation: MRC Epidemiology Unit, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Katrien
authors.initials: K
authors.lastname: Wijndaele
mesh_terms: D006801:Humans; D015994:Incidence; D009369:Neoplasms / Q000453:epidemiology*; D011446:Prospective Studies; D012306:Risk; D018570:Risk Assessment; D057185:Sedentary Behavior