title: Cardiorespiratory fitness, body mass index, and cancer mortality: a cohort study of Japanese men.
abstract: BACKGROUND
  The aim of this study is to investigate the independent and joint effects of cardiorespiratory fitness (CRF) and body mass index (BMI) on cancer mortality in a low body mass index population.
  
  
  METHODS
  We evaluated CRF and BMI in relation to cancer mortality in 8760 Japanese men. The median BMI was 22.6 kg/m2 (IQR: 21.0-24.3). The mean follow-up period was more than 20 years. Hazard ratios and 95% CI were obtained using a Cox proportional hazards model while adjusting for several confounding factors.
  
  
  RESULTS
  Using the 2nd tertile of BMI (21.6-23.6 kg/m2) as reference, hazard ratios and 95% CI for the lowest tertile of BMI (18.5-21.5) were 1.26 (0.87-1.81), and 0.92 (0.64-1.34) for the highest tertile (23.7-37.4). Using the lowest tertile of CRF as reference, hazard ratios and 95% CIs for 2nd and highest tertiles of CRF were 0.78 (0.55-1.10) and 0.59 (0.40-0.88). We further calculated hazard ratios according to groups of men cross-tabulated by tertiles of CRF and BMI. Among men in the second tertile of BMI, those belonging to the lowest CRF tertile had a 53% lower risk of cancer mortality compared to those in the lowest CRF tertile (hazard ratio: 0.47, 95% CI: 0.23-0.97). Among those in the highest BMI tertile, the corresponding hazard ratio was 0.54 (0.25-1.17).
  
  
  CONCLUSIONS
  These results suggest that high CRF is associated with lower cancer mortality in a Japanese population of men with low average BMI.
authors.affiliation: Department of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan. s-sawada@nih.go.jp.
authors.forename: Susumu S
authors.initials: SS
authors.lastname: Sawada
authors.forename: I-Min
authors.initials: IM
authors.lastname: Lee
authors.forename: Hisashi
authors.initials: H
authors.lastname: Naito
authors.forename: Ryo
authors.initials: R
authors.lastname: Kakigi
authors.forename: Sataro
authors.initials: S
authors.lastname: Goto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kanazawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Tsukamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Muto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000208:ethnology* / Q000401:mortality*; D010809:Physical Fitness; D016016:Proportional Hazards Models; D012907:Smoking / Q000208:ethnology; D055815:Young Adult