Sensitivity to Thyroid Hormones and Reduced Glomerular Filtration in Children and Adolescents with Overweight or Obesity.

BACKGROUND

Reduced central sensitivity to thyroid hormones (THs) has been observed in euthyroid adults with reduced renal function. This topic is unexplored in young people with overweight or obesity (OW/OB).

OBJECTIVE

The aim of this study was to evaluate the association between sensitivity to TH and mild reduced estimated glomerular filtration rate (MReGFR) in euthyroid children and adolescents with OW/OB.

METHODS

Data of 788 euthyroid children and adolescents with OW/OB (aged 6-16 years), recruited from seven Italian centers for the care of OW/OB, were evaluated. Peripheral sensitivity to TH was estimated through the FT3/FT4 ratio, while central sensitivity was assessed by estimating TSH index (TSHI), thyrotroph T4 resistance index, thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI). MReGFR was defined by an eGFR value ≥60 and <90 mL/min/1.73 m2.

RESULTS

Subjects with MReGFR had significantly lower levels of FT3/FT4 ratio (0.43 ± 0.09 vs. 0.44 ± 0.10; p = 0.028) and higher levels of TSH (2.89 ± 1.00 vs. 2.68 ± 0.99; p = 0.019), TSHI (2.95 ± 0.45 vs. 2.85 ± 0.55; p = 0.031), TFQI [1.00 (0.98-1.00) versus 1.00 (0.97-1.00); p = 0.046], and PTFQI (0.66 ± 0.17 vs. 0.60 ± 0.23; p = 0.006) compared with individuals with normal eGFR. Odds ratio of MReGFR raised of 1.2-3.2-fold for each increase of 1 mIU/L in TSH, 1 unit in TSHI, and PTFQI, but not for FT3/FT4 ratio.

CONCLUSION

MReGFR is associated with reduced indices of central sensitivity to TH in euthyroid children and adolescents with OW/OB. This preliminary observation should be confirmed in prospective studies.