title: Body mass index and weight change in men with prostate cancer: progression and mortality.
abstract: OBJECTIVE
  Body mass index (BMI) is a modifiable lifestyle factor that has been associated with an increased risk of fatal prostate cancer and biochemical recurrence. The main purpose of the present study was to investigate the association between the exposure BMI at the time of a prostate cancer diagnosis and weight change after diagnosis, and the outcomes of prostate cancer progression and mortality in a large cohort study.
  
  
  METHODS
  Data from 4,376 men diagnosed with clinically localized prostate cancer between 1997 and 2002 were analyzed. BMI and weight change were self-reported in 2007. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were estimated in complete-case analysis (n = 3,214) using Cox proportional hazards models.
  
  
  RESULTS
  Progression was experienced among 639 (14.6 %) of the study participants, and in total, 450 (10.3 %) deaths of any cause and 134 (3.1 %) prostate cancer-specific deaths were recorded during follow-up. Obese men had a 47 % increased rate of overall mortality compared to normal weight men (HR 1.47, 95 % CI 1.03-2.10). No statistically significant associations were found for BMI and prostate cancer progression or prostate cancer-specific mortality. A weight loss >5 % after diagnosis almost doubled the rate of overall mortality compared to maintaining a stable weight (HR 1.94, 95 % CI 1.41-2.66), while a weight gain >5 % was associated with an almost doubled increased rate of prostate cancer-specific mortality (HR 1.93, 95 % CI 1.18-3.16).
  
  
  CONCLUSIONS
  Being obese was associated with an increased rate of overall mortality, and gaining weight after a prostate cancer diagnosis was associated with an increased rate of prostate cancer-specific mortality.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Nobels väg 12A, 171 77, Stockholm, Sweden, stephanie.bonn@ki.se.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Bonn
authors.forename: Fredrik
authors.initials: F
authors.lastname: Wiklund
authors.forename: Arvid
authors.initials: A
authors.lastname: Sjölander
authors.forename: Robert
authors.initials: R
authors.lastname: Szulkin
authors.forename: Pär
authors.initials: P
authors.lastname: Stattin
authors.forename: Erik
authors.initials: E
authors.lastname: Holmberg
authors.forename: Henrik
authors.initials: H
authors.lastname: Grönberg
authors.forename: Katarina
authors.initials: K
authors.lastname: Bälter
mesh_terms: D000368:Aged; D015992:Body Mass Index; D018450:Disease Progression; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology; D013548:Sweden / Q000453:epidemiology; D015430:Weight Gain; D015431:Weight Loss