title: Prediagnostic body mass index and pancreatic cancer survival.
abstract: OBJECTIVE
  Although obesity is associated with increased incidence of pancreatic cancer, studies have not prospectively evaluated prediagnostic body mass index (BMI) and survival.
  
  
  METHODS
  We analyzed survival by prediagnostic BMI assessed in 1986 among 902 patients from two large prospective cohorts diagnosed from 1988 to 2010. We estimated hazard ratios (HRs) for death using Cox proportional hazards models, with adjustment for age, sex, race/ethnicity, smoking, diagnosis year, and stage. We evaluated the temporal association of BMI with survival by grouping reported BMI by 2-year lag-time intervals before diagnosis.
  
  
  RESULTS
  The multivariable-adjusted HR for death was 1.53 (95% CI, 1.11 to 2.09) comparing patients with BMI ≥ 35 kg/m(2) with those with BMI < 25 kg/m(2) (P trend = .001), which was similar after adjustment for stage. The association of BMI with survival was stronger with longer lag times between reported BMI and cancer diagnosis. Among patients with BMI collected 18 to 20 years before diagnosis, HR for death was 2.31 (95% CI, 1.48 to 3.61; P trend < .001), comparing obese with healthy-weight patients. No statistically significant differences were seen by cohort, smoking status, or stage, although the association was stronger among never-smokers (HR, 1.61; 95% CI, 1.01 to 2.57; P trend = .002) than ever-smokers (HR, 1.36; 95% CI, 0.86 to 2.15; P trend = .63), comparing BMI ≥ 35 kg/m(2) with BMI < 25 kg/m(2). Higher prediagnostic BMI was associated with more advanced stage at diagnosis, with 72.5% of obese patients presenting with metastatic disease versus 59.4% of healthy-weight patients (P = .02).
  
  
  CONCLUSIONS
  Higher prediagnostic BMI was associated with statistically significantly decreased survival among patients with pancreatic cancer from two large prospective cohorts.
authors.affiliation: Chen Yuan, Shuji Ogino, Kimmie Ng, Zhi Rong Qian, Douglas A. Rubinson, and Brian M. Wolpin, Dana-Farber Cancer Institute; Ying Bao, Shuji Ogino, Kimmie Ng, Meir J. Stampfer, Edward L. Giovannucci, and Brian M. Wolpin, Brigham and Women's Hospital, Harvard Medical School; and Chen Wu, Peter Kraft, Shuji Ogino, Meir J. Stampfer, and Edward L. Giovannucci, Harvard School of Public Health, Boston, MA.
authors.forename: Chen
authors.initials: C
authors.lastname: Yuan
authors.forename: Ying
authors.initials: Y
authors.lastname: Bao
authors.forename: Chen
authors.initials: C
authors.lastname: Wu
authors.forename: Peter
authors.initials: P
authors.lastname: Kraft
authors.forename: Shuji
authors.initials: S
authors.lastname: Ogino
authors.forename: Kimmie
authors.initials: K
authors.lastname: Ng
authors.forename: Zhi Rong
authors.initials: ZR
authors.lastname: Qian
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Rubinson
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Edward L
authors.initials: EL
authors.lastname: Giovannucci
authors.forename: Brian M
authors.initials: BM
authors.lastname: Wolpin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000150:complications*; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D016016:Proportional Hazards Models; D018570:Risk Assessment / Q000706:statistics & numerical data; D012307:Risk Factors; D012907:Smoking; D015996:Survival Rate