Prevalence, Metabolic Features, and Prognosis of Metabolically Healthy Obese Italian Individuals

The Cremona Study

  1. Gianluca Perseghin, MD1,2
  1. 1Division of Metabolic and Cardiovascular Sciences, Istituto Scientifico H San Raffaele, Milan, Italy;
  2. 2Department of Sport Sciences, Nutrition, and Health, Università degli Studi di Milano, Milan, Italy;
  3. 3Diabetes Research Institute, Istituto Scientifico H San Raffaele, Milan, Italy;
  4. 4Medical Direction, Istituto Scientifico H San Raffaele, Milan, Italy;
  5. 5Servizio Epidemiologia ASL della Provincia di Cremona, Istituto Einaudi, Cremona, Italy;
  6. 6Istituto Nazionale dei Tumori, Milan, Italy;
  7. 7Department of Research and Development, AstraZeneca, Molndal, Sweden.
  1. Corresponding author: Gianluca Perseghin, perseghin.gianluca{at}hsr.it.

Abstract

OBJECTIVE Some obese individuals have normal insulin sensitivity. It is controversial whether this phenotype is associated with increased all-cause mortality risk.

RESEARCH DESIGN AND METHODS Fifteen-year all-cause mortality data were obtained through the Regional Health Registry for 2,011 of 2,074 Caucasian middle-aged individuals of the Cremona Study, a population study on the prevalence of diabetes in Italy. Individuals were divided in four categories according to BMI (nonobese: <30 kg/m2; obese: ≥30 kg/m2) and estimated insulin resistance (insulin sensitive: homeostasis model assessment of insulin resistance <2.5; insulin resistant ≥2.5).

RESULTS Obese insulin-sensitive subjects represented 11% (95% CI 8.1–14.5) of the obese population. This phenotype had similar BMI but lower waist circumference, blood pressure, fasting glucose, triglycerides, and fibrinogen and higher HDL cholesterol than obese insulin-resistant subjects. In the 15-year follow-up, 495 deaths (cardiovascular disease [CVD]: n = 221; cancer: n = 180) occurred. All-cause mortality adjusted for age and sex was higher in the obese insulin-resistant subjects (hazard ratio 1.40 [95% CI 1.08–1.81], P = 0.01) but not in the obese insulin-sensitive subjects (0.99 [0.46–2.11], P = 0.97) when compared with nonobese insulin-sensitive subjects. Also, mortality for CVD and cancer was higher in the obese insulin-resistant subjects but not in the obese insulin-sensitive subjects when compared with nonobese insulin-sensitive subjects.

CONCLUSIONS In contrast to obese insulin-resistant subjects, metabolically healthy obese individuals are less common than previously thought and do not show increased all-cause, cancer, and CVD mortality risks in a 15-year follow-up study.

Footnotes

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  • Received April 9, 2010.
  • Accepted October 4, 2010.

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  1. Diabetes Care vol. 34 no. 1 210-215
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