Background: In most individuals, obesity and insulin resistance coexist. However, some individuals have excessive adipose tissue mass but remain insulin sensitive. Moreover, lean individuals can develop acute inflammation-induced insulin resistance, even without excess adipose tissue mass.
Objective: Our aim was to compare inflammatory markers in overweight, insulin-sensitive and lean, insulin-resistant healthy subjects.
Methods: A cross-sectional study with 1098 participants (CAMELIA project) was conducted in family doctor primary care program at Niteroi, RJ, Brazil. In the present substudy, we have selected non-obese healthy subjects (n = 203). Insulin resistance was defined by a homeostatic model assessment (HOMA-IR) >2.6, and overweight subject BMIs were 25< BMI <30 kg/m2. Associations were estimated through binary logistic regression with generalized estimation equation models.
Results: We compared overweight, insulin-sensitive healthy individuals (n = 74) with a mean age of 39.2 ± 1.3 and lean, insulin-resistant healthy individuals (n = 18) with a mean age of 31.9 ± 3.6. C-reactive protein levels were positively correlated with body mass index in the lean, insulin-resistant group. In the multiple regression model, a positive association was observed with MCP-1 and IL-6 expression after adjustment for age, waist circumference, glycated hemoglobin, resistin, adiponectin, C-reactive protein and PAI-1 levels.
Conclusion: Our findings suggest that a lean, insulin-resistant subject may have higher pro-inflammatory marker levels (MCP-1, IL-6 and resistin) than an overweight, insulin-sensitive subject. This suggest an early risk phenotype that should further be investigated for possible prognostic implications.
Keywords: Adipokines; Adiponectin; BMI; C reactive protein; Cytokine; HOMA; Inflammation; Insulin resistance; Lean; Obesity.