title: Physical activity and risk of endometrial cancer in a prospective cohort study (United States).
abstract: OBJECTIVE
  To examine the physical activity and endometrial cancer relationship in a prospective study of US women enrolled in the Breast Cancer Detection Demonstration Project (BCDDP) Follow-up Study.
  
  
  METHODS
  We assessed past-year physical activity of all types in 23,369 women who returned the baseline questionnaire (1987-1989) and had no prior hysterectomy and/or endometrial cancer. Cox proportional hazards models were used to estimate age, education, and parity-adjusted rate ratios (RR) and 95% confidence intervals (CI) for the 253 confirmed endometrial cancer cases identified during an average 8.2 years of follow-up (ending 1995-1998).
  
  
  RESULTS
  There were no dose-response relationships with either total or vigorous physical activity; however, compared to the lowest total activity quartile, the higher four quartiles had a non-significantly lower risk (RR = 0.8, CI = 0.6-1.0). The association with moderate activity varied with follow-up time: RRs (CI) for a 1 h increase in daily moderate activity within 2-year intervals of follow-up (< or = 2, 2.1-4.9, 5.0-8.0, > 8 years) were 1.1 (1.0, 1.2), 1.0 (0.9, 1.1), 1.0 (0.9, 1.1), 1.0 (0.9, 1.1), and 0.8 (0.7, 1.0), respectively.
  
  
  CONCLUSIONS
  These data suggest that recent physical activity is not strongly related to the risk of endometrial cancer, and that prolonged exposure and longer follow-up may be necessary.
authors.affiliation: Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, Bethesda, MD, USA. lisa.colbert@att.net
authors.forename: Lisa H
authors.initials: LH
authors.lastname: Colbert
authors.forename: James V
authors.initials: JV
authors.lastname: Lacey
authors.forename: Catherine
authors.initials: C
authors.lastname: Schairer
authors.forename: Paul
authors.initials: P
authors.lastname: Albert
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Demetrius
authors.initials: D
authors.lastname: Albanes
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D015331:Cohort Studies; D016889:Endometrial Neoplasms / Q000453:epidemiology* / Q000517:prevention & control*; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D010809:Physical Fitness; D011446:Prospective Studies; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology