title: Physical activity and endometrial cancer risk, a systematic review of current evidence.
abstract: OBJECTIVE
  To assess the epidemiologic evidence for the association between physical activity and endometrial cancer risk, taking into account the methodologic quality of each study.
  
  
  METHODS
  Systematic review, best evidence synthesis.
  
  
  METHODS
  Studies were identified through a systematic review of literature available on PubMed through December 2006.
  
  
  METHODS
  We included cohort and case-control studies that assessed total and/or leisure time and/or occupational activities in relation to the incidence of endometrial cancer. The methodologic quality of the studies was assessed with a comprehensive scoring system.
  
  
  RESULTS
  The included cohort (n = 7) and case-control (n = 13) studies consistently show that physical activity is associated with a decreased risk of endometrial cancer. The best evidence synthesis showed that the majority (80%) of 10 high-quality studies found risk reductions of >20%. Pooling of seven high-quality cohort studies that measured total, leisure time, or occupational activity showed a significantly decreased risk of endometrial cancer (summary estimate: OR, 0.77; 95% CI, 0.70-0.85) for the most active women. Case control studies with relatively unfavorable quality scores reported divergent risk estimates, between 2-fold decreased and 2-fold increased risk. Effect modification by body mass index or menopausal status was not consistently observed. Evidence for an effect of physical activity during childhood or adolescence was limited.
  
  
  CONCLUSIONS
  Physical activity seems to be associated with a reduction in the risk of endometrial cancer, which is independent of body weight. Further studies, preferably prospective cohort studies, are needed to determine the magnitude of the risk reduction and to assess which aspects of physical activity contribute most strongly to the reduced risk and in which period of life physical activity is most effective.
authors.affiliation: Department of Epidemiology, the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands.
authors.forename: Dorien W
authors.initials: DW
authors.lastname: Voskuil
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Monninkhof
authors.forename: Sjoerd G
authors.initials: SG
authors.lastname: Elias
authors.forename: Femke A
authors.initials: FA
authors.lastname: Vlems
authors.forename: Flora E
authors.initials: FE
authors.lastname: van Leeuwen
mesh_terms: D016889:Endometrial Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D005260:Female; D006801:Humans; D015994:Incidence; D009043:Motor Activity; D012307:Risk Factors