title: Body-mass index and mortality among adults with incident type 2 diabetes.
abstract: BACKGROUND
  The relation between body weight and mortality among persons with type 2 diabetes remains unresolved, with some studies suggesting decreased mortality among overweight or obese persons as compared with normal-weight persons (an "obesity paradox").
  
  
  METHODS
  We studied participants with incident diabetes from the Nurses' Health Study (8970 participants) and Health Professionals Follow-up Study (2457 participants) who were free of cardiovascular disease and cancer at the time of a diagnosis of diabetes. Body weight shortly before diagnosis and height were used to calculate the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters). Multivariable Cox models were used to estimate the hazard ratios and 95% confidence intervals for mortality across BMI categories.
  
  
  RESULTS
  There were 3083 deaths during a mean period of 15.8 years of follow-up. A J-shaped association was observed across BMI categories (18.5 to 22.4, 22.5 to 24.9 [reference], 25.0 to 27.4, 27.5 to 29.9, 30.0 to 34.9, and ≥35.0) for all-cause mortality (hazard ratio, 1.29 [95% confidence interval {CI}, 1.05 to 1.59]; 1.00; 1.12 [95% CI, 0.98 to 1.29]; 1.09 [95% CI, 0.94 to 1.26]; 1.24 [95% CI, 1.08 to 1.42]; and 1.33 [95% CI, 1.14 to 1.55], respectively). This relationship was linear among participants who had never smoked (hazard ratios across BMI categories: 1.12, 1.00, 1.16, 1.21, 1.36, and 1.56, respectively) but was nonlinear among participants who had ever smoked (hazard ratios across BMI categories: 1.32, 1.00, 1.09, 1.04, 1.14, and 1.21) (P=0.04 for interaction). A direct linear trend was observed among participants younger than 65 years of age at the time of a diabetes diagnosis but not among those 65 years of age or older at the time of diagnosis (P<0.001 for interaction).
  
  
  CONCLUSIONS
  We observed a J-shaped association between BMI and mortality among all participants and among those who had ever smoked and a direct linear relationship among those who had never smoked. We found no evidence of lower mortality among patients with diabetes who were overweight or obese at diagnosis, as compared with their normal-weight counterparts, or of an obesity paradox. (Funded by the National Institutes of Health and the American Diabetes Association.).
authors.affiliation: From the Departments of Nutrition (D.K.T., A.P., C.L.J., E.J.O., E.L.D., W.C.W., F.B.H.) and Epidemiology (W.C.W., J.E.M., F.B.H.), Harvard School of Public Health, and the Channing Division of Network Medicine (E.J.O., E.L.D., W.C.W., F.B.H.) and the Division of Preventive Medicine (J.E.M.), Department of Medicine, Brigham and Women's Hospital and Harvard Medical School - all in Boston; and Saw Swee Hock School of Public Health and Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (A.P.).
authors.forename: Deirdre K
authors.initials: DK
authors.lastname: Tobias
authors.forename: An
authors.initials: A
authors.lastname: Pan
authors.forename: Chandra L
authors.initials: CL
authors.lastname: Jackson
authors.forename: Eilis J
authors.initials: EJ
authors.lastname: O'Reilly
authors.forename: Eric L
authors.initials: EL
authors.lastname: Ding
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: JoAnn E
authors.initials: JE
authors.lastname: Manson
authors.forename: Frank B
authors.initials: FB
authors.lastname: Hu
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001835:Body Weight; D002423:Cause of Death; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000401:mortality*; D016016:Proportional Hazards Models