title: Physical activity and risk of colon cancer in a cohort of Danish middle-aged men and women.
abstract: OBJECTIVE
  To investigate the effects of occupational activity and leisure time activity on incident colon cancer risk in a Danish middle-aged population.
  
  
  METHODS
  In the cohort, Diet, Cancer and Health, which included 28,356 women and 26,122 men aged 50-64 years at baseline, 140 women and 157 men were diagnosed with colon cancer from 1993 to 2003. The associations between occupational and leisure time activity in terms of a MET-score and the single activities, sports, cycling, walking, gardening, housework and do-it-yourself work, and incident colon cancer were investigated. Leisure time activity was investigated in two ways using the Cox proportional hazards model: by comparison of active versus non-active and by investigating a possible dose-response relationship while allowing a separate association for non-active individuals.
  
  
  RESULTS
  No associations were found between risk of colon cancer and occupational activity, MET-hours per week of total leisure time activity, residuals from a regression of each activity on the total MET-hours or the time spent on any of the six types of leisure time activities. However, a borderline significant association was found with the number of activities in which the participants were active. For each additional activity IRR = 0.87 (0.76-1.00) for women and IRR = 0.88 (0.78-1.00) for men.
  
  
  CONCLUSIONS
  Our data do not support the evidence of an inverse association between colon cancer risk and occupational activity or leisure time activity, but avoiding a sedentary lifestyle by participating in different activities may reduce colon cancer risk.
authors.affiliation: Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, 2100, Copenhagen, Denmark. nina@cancer.dk
authors.forename: Nina Føns
authors.initials: NF
authors.lastname: Johnsen
authors.forename: Jane
authors.initials: J
authors.lastname: Christensen
authors.forename: Birthe Lykke
authors.initials: BL
authors.lastname: Thomsen
authors.forename: Anja
authors.initials: A
authors.lastname: Olsen
authors.forename: Steffen
authors.initials: S
authors.lastname: Loft
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
mesh_terms: D015992:Body Mass Index; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000453:epidemiology*; D003718:Denmark / Q000453:epidemiology; D004032:Diet; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011998:Recreation; D012306:Risk; D012959:Socioeconomic Factors; D014937:Work