Body mass index, diabetes, and mortality in French women: explaining away a "paradox"

Epidemiology. 2014 Jan;25(1):10-4. doi: 10.1097/EDE.0000000000000031.


Background: Obesity is associated with increased mortality in the general population but, paradoxically, with decreased mortality in persons with diabetes.

Methods: Among 88,373 French women participating in the E3N-EPIC study who were free of diabetes in 1990, we estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality for body mass index (BMI) levels by diabetes status.

Results: During an average 16.7 years of follow-up, 2421 cases of diabetes were identified and 3750 deaths occurred. For overweight/obese versus normal-weight women, the HR of mortality was 1.42 (95% CI = 1.32-1.53) in women without diabetes and 0.69 (0.40-1.18) in women with incident diabetes. As BMI increased, mortality among women without diabetes increased and that among women with diabetes decreased.

Conclusions: We found the obesity "paradox" among women with and without incident diabetes in the same population. Selection bias may be a simple explanation for this "paradox."

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Body Mass Index
  • Comorbidity
  • Confidence Intervals
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / mortality*
  • Female
  • France / epidemiology
  • Humans
  • Longitudinal Studies
  • Middle Aged
  • Obesity / epidemiology
  • Obesity / mortality*
  • Overweight / epidemiology
  • Overweight / mortality
  • Proportional Hazards Models
  • Risk Factors
  • Selection Bias