This downward trend continued across the obesity classes: individuals with Class I obesity (BMI 30.0–34.9) had a median of 24.6 nmol/L (IQR: 19.7–31.5 nmol/L), those with Class II obesity (BMI 35.0–39.9) had 19.9 nmol/L (IQR: 16.2–25.1 nmol/L), and those with Class III obesity (BMI ≥ 40.0) showed a median SHBG level of 24.2 nmol/L (IQR: 15.4–28.2 nmol/L). Here, SHBG is linked to obesity due to melanocortin 4 receptor deficiency.