Thyroid function is more strongly associated with body impedance than anthropometry in healthy subjects

Since fat-free tissues are responsible for 95% of basal energy expenditure, fat-free mass is expected to be a better determinant of thyroid size and function than anthropometry. We tested the hypothesis that fat-free tissues as qualitatively determined by body resistance (R) at 50 kHz are more strongly associated with TSH than anthropometric indicators in healthy subjects. A number of 78 euthyroid adults of both sexes were consecutively studied. R was the best single predictor of TSH (R²_adj=0.65, p2_adj=0.29, p