Diabetes, Metabolic Syndrome and Obesity (Feb 2020)

Resting Whole Body Energy Metabolism in Class 3 Obesity; from Preserved Insulin Sensitivity to Overt Type 2 Diabetes

  • Manzoni G,
  • Oltolini A,
  • Perra S,
  • Muraca E,
  • Ciardullo S,
  • Pizzi M,
  • Castoldi G,
  • Lattuada G,
  • Pizzi P,
  • Perseghin G

Journal volume & issue
Vol. Volume 13
pp. 489 – 497

Abstract

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Giuseppina Manzoni,1 Alice Oltolini,1 Silvia Perra,1 Emanuele Muraca,1 Stefano Ciardullo,1,2 Mattia Pizzi,3 Giovanna Castoldi,2 Guido Lattuada,1 Pietro Pizzi,3 Gianluca Perseghin1,2 1Department of Medicine and Rehabilitation, Policlinico di Monza, Monza, Italy; 2Department of Medicine and Surgery, Università Degli Studi di Milano Bicocca, Monza, Italy; 3Centre for Obesity Research, Policlinico di Monza, Monza, ItalyCorrespondence: Gianluca PerseghinDepartment of Medicine and Rehabilitation, Policlinico di Monza, Via Modigliani 10, Monza, MB 20900, ItalyTel +39 039 281 0430Email [email protected]: Insulin resistance and diabetes may influence separately or in combination whole body energy metabolism.Objective: To assess the impact of insulin resistance and/or overt type 2 diabetes on resting energy expenditure (REE) in class 3 obese individuals.Design and Setting: Retrospective, cross-sectional analysis of a set of data about individuals attending the outpatients service of a single center of bariatric surgery between January 2015 and December 2017.Patients: We screened 382 patients in which abnormal thyroid function was excluded, and segregated them in three groups of subjects: patients with type 2 diabetes (T2DM; n=70), non-diabetic insulin-resistant patients with HOMA-IR ≥ 3 (n=236), non-diabetic insulin-sensitive patients with HOMA-IR < 3 (n=75).Main Outcome Measure: Resting energy expenditure (REE), body composition and insulin resistance assessed using indirect calorimetry, bioimpedance and HOMA-IR.Results: Non-diabetic insulin-sensitive patients resulted to be younger, with lower BMI and higher prevalence of female subjects; meanwhile, non-diabetic but insulin-resistant patients and T2DM patients were not different in terms of anthropometric parameters. REE was higher in T2DM than in non-diabetic insulin-resistant and insulin-sensitive individuals when expressed as percent of the predicted REE (based on Harris Benedict equation) (p< 0.0001) or when adjusted for kg of free fat mass (p< 0.0001) and was found to be higher also in insulin-resistant vs insulin-sensitive patients (p< 0.001). The respiratory quotient was different between groups (0.87± 0.11, 0.86± 0.12 and 0.91± 0.14 in T2DM, insulin-resistant and insulin-sensitive patients, respectively; p< 0.03). Regression analysis confirmed that HOMA-IR was independently associated with the REE (R2=0.110, p< 0.001).Conclusion: Class 3 obese patients with normal insulin sensitivity are characterized by reduced fasting REE in comparison to insulin-resistant obese patients and obese patients with short duration of diabetes supporting the hypothesis that down-regulation of nutrients’ oxidative disposal may represent an adaptation of energy metabolism in obese individuals with preserved insulin sensitivity.Keywords: indirect calorimetry, insulin resistance, energy expenditure, bariatric surgery, respiratory quotient

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