title: Postdiagnosis body mass index and risk of mortality in colorectal cancer survivors: a prospective study and meta-analysis.
abstract: OBJECTIVE
  Aim of this study was to investigate the association between postdiagnosis body mass index (BMI) and all-cause mortality in colorectal cancer (CRC) survivors in a prospective study and meta-analysis.
  
  
  METHODS
  We conducted a prospective cohort study on 2,143 CRC survivors in Germany. Participants were recruited to the study on average 4 years after diagnosis, and postdiagnosis BMI was assessed at recruitment using a self-administered questionnaire. CRC survivors were followed up for a mean time of 3.5 years. The association between BMI and all-cause mortality was investigated using multivariable Cox proportional hazards models. Additionally, we performed a meta-analysis of studies on postdiagnosis BMI and all-cause mortality (n = 5, including this study) by applying random-effects models.
  
  
  RESULTS
  In the prospective analysis, 349 participants died. BMI was not statistically significantly associated with all-cause mortality. Compared to normal weight survivors, the hazard ratios (HRs) [95% confidence interval (CI)] for all-cause mortality in underweight, overweight and obese survivors were 1.65 (0.79-3.45), 0.80 (0.62-1.03) and 0.84 (0.62-1.14), respectively. In the meta-analysis, individuals with underweight were at increased risk for all-cause mortality [HR (95% CI) 1.72 (1.18-2.49)], whereas individuals with overweight had a lower risk [HR (95% CI) 0.79 (0.71-0.88)], compared to normal weight subjects. For obesity, the risk of mortality was also reduced with only borderline significance [HR (95% CI) 0.88 (0.77-1.00)].
  
  
  CONCLUSIONS
  While the present study as well as single previously published studies showed that overweight was associated with a non-significant reduced risk for all-cause mortality, our meta-analysis indicated a decreased mortality risk among overweight CRC survivors.
authors.affiliation: Institute of Epidemiology, Christian-Albrechts University of Kiel, Campus UKSH, Arnold-Heller-Str. 3, Haus 1, 24105, Kiel, Germany, sabrina.schlesinger@epi.uni-kiel.de.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Schlesinger
authors.forename: Sabine
authors.initials: S
authors.lastname: Siegert
authors.forename: Manja
authors.initials: M
authors.lastname: Koch
authors.forename: Jessica
authors.initials: J
authors.lastname: Walter
authors.forename: Nils
authors.initials: N
authors.lastname: Heits
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hinz
authors.forename: Gunnar
authors.initials: G
authors.lastname: Jacobs
authors.forename: Jochen
authors.initials: J
authors.lastname: Hampe
authors.forename: Clemens
authors.initials: C
authors.lastname: Schafmayer
authors.forename: Ute
authors.initials: U
authors.lastname: Nöthlings
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D015992:Body Mass Index; D002423:Cause of Death; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000401:mortality*; D015897:Comorbidity; D005260:Female; D005858:Germany; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D050177:Overweight / Q000453:epidemiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires; D015996:Survival Rate; D017741:Survivors / Q000706:statistics & numerical data*; D013851:Thinness / Q000453:epidemiology