Low irisin levels are associated with increased body weight and an adverse metabolic profile

To assess whether plasma irisin is associated with anthropometric, body composition, and metabolic parameters according to body mass index.

A prospective cohort study was conducted at a tertiary referral hospital in Southern Brazil. Patients were divided according to body mass index: Group 1 (body mass index = 18.5 - 29.9 kg/m2; n = 15), Group 2 (body mass index = 30 - 39.9 kg/m2; n = 36), and Group 3 (body mass index ≥ 40 kg/m2; n = 30). Groups 1 and 2 underwent cholecystectomy, while Group 3 underwent Roux-en-Y gastric bypass. All groups were evaluated at baseline, and Groups 2 and 3 were re-evaluated 6 months later. Body composition was assessed using X-ray absorptiometry, and resting energy expenditure was measured by indirect calorimetry.

The study subjects were predominantly female (75%), white (82%), with a mean age of 46 ± 14 years. Group 3 had lower irisin levels compared to Group 2: 9.1 ± 2.2 versus 10.7 ± 2.8 ng/mL; p = 0.038). Irisin was negatively correlated with weight (r = -0.246; p = 0.042), waist circumference (r = -0.272; p = 0.024), glucose (r = -0.259; p = 0.039), glycated hemoglobin (r = -0.283; p = 0.024), triglycerides (r = -0.414; p = 0.024), and positively correlated with HDL (r = 0.280; p = 0.029).

Irisin showed an inverse correlation with insulin-related metabolic pathways, suggesting its potential involvement in insulin resistance states such as obesity and type 2 diabetes.