Thyroid homeostasis indices by category of healthy weight, overweight (BMI from 85th to 94th percentile for age and sex), or obese (≥95th percentile for age and sex). The mean value for each category is reported in the columns. (A) TSH was significantly higher in adolescents with obesity compared with both healthy-weight and overweight subjects (F-ratio 7.04, p = 0.0009). (B) There was no difference in fT3 levels by weight category. (C) Mean fT4 levels were significantly lower in obese than in healthy-weight or overweight subjects (F-ratio 6.2172, p = 0.0019). (D) Obese adolescents had a higher fT3:fT4 ratio than healthy weight or overweight adolescents (F-ratio 7.81, p = 0.0004).