Impact of weight loss on inflammatory proteins and their association with the insulin resistance syndrome in morbidly obese patients

Arterioscler Thromb Vasc Biol. 2003 Jun 1;23(6):1042-7. doi: 10.1161/01.ATV.0000073313.16135.21. Epub 2003 Apr 24.


Objective: Obesity is closely linked to the insulin resistance syndrome (IRS), type 2 diabetes, and cardiovascular disease, the primary cause of morbidity and mortality in these patients. Elevated levels of C-reactive protein (CRP) and interleukin-6 (IL-6), indicating chronic subclinical inflammation, have been associated with features of the IRS and incident cardiovascular disease.

Methods and results: We studied the cross-sectional and longitudinal relation of CRP, IL-6, and tumor necrosis factor-alpha (TNF-alpha) with features of the IRS in 37 morbidly obese patients with different stages of glucose tolerance before and 14 months after gastric surgery. Weight loss after gastric surgery induced a significant shift from diabetes (37% vs 3%) to impaired glucose tolerance (40% vs 33%) and normal glucose tolerance (23% vs 64%). The baseline concentration of IL-6 was correlated with TNF-alpha (r=0.59, P<0.01) and CRP (r=0.44, P<0.05) levels. TNF-alpha, IL-6, and CRP were significantly correlated with insulin resistance estimated by the homeostatic model assessment (r=0.48, P<0.05; r=0.56, P<0.01; and r=0.35, P<0.05, respectively). Concentrations of CRP and IL-6 decreased after weight loss (median, 8.6 and interquartile range, 2.7/14.5 vs 2.5 and 1.2/4.1 mg/L; P<0.006, and 5.13 and 2.72/12.15 vs 3.95 and 1.97/5.64 pg/mL, P<0.02, respectively), whereas serum levels of TNF-alpha remained unchanged (8.6 and 6.3/18.8 vs 11.7 and 5.8/17.2 pg/mL; NS.). Multiple regression analysis revealed that the decrease in insulin resistance remained independently and significantly correlated with the decrease in IL-6 concentrations (P<0.01) and the decrease in body mass index with the decrease in CRP (P<0.05), respectively.

Conclusions: Weight loss in morbidly obese patients induces a significant decrease of CRP and IL-6 concentrations in association with an improvement of the IRS.

MeSH terms

  • Adult
  • Blood Glucose / analysis
  • Body Mass Index
  • C-Reactive Protein / analysis*
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / complications
  • Female
  • Fibrinogen / analysis
  • Gastroplasty*
  • Humans
  • Inflammation / blood*
  • Insulin / blood
  • Insulin Resistance*
  • Interleukin-6 / blood*
  • Lipids / blood
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity, Morbid / blood*
  • Obesity, Morbid / complications
  • Obesity, Morbid / surgery
  • Tumor Necrosis Factor-alpha / analysis*
  • Weight Loss*


  • Blood Glucose
  • Insulin
  • Interleukin-6
  • Lipids
  • Tumor Necrosis Factor-alpha
  • Fibrinogen
  • C-Reactive Protein