Hyperthyrotropinemia in obese children is reversible after weight loss and is not related to lipids.
BACKGROUND
There is some controversy whether T(4) treatment is indicated in obese humans with hyperthyrotropinemia.


OBJECTIVE
The objective of this study was to examine whether hyperthyrotropinemia is a cause or a consequence of obesity.


METHODS
The study was designed as a cross-sectional comparison between obese and lean children and includes a 1-yr follow-up study.


METHODS
The study was set in a primary care facility.


METHODS
The patients were 246 obese and 71 lean children.


METHODS
The 1-yr intervention program was based on exercise, behavior therapy, and nutrition education.


METHODS
The main outcome measures were TSH, free T(3) (fT3), free T(4) (fT4), high-density lipoprotein, low-density lipoprotein, and total cholesterol at baseline and 1 yr later.


RESULTS
TSH (P = 0.009) and fT3 (P = 0.003) concentrations were significantly higher in obese children than in normal weight children, whereas there was no difference in fT4 levels (P = 0.804). Lipids did not correlate significantly to thyroid hormones in cross-sectional and longitudinal analyses. fT3, fT4, and lipids did not differ significantly in the 43 (17%) children with TSH levels above the normal range from the children with TSH levels within the normal range. Substantial weight loss in 49 obese children led to a significant reduction of TSH (P = 0.035) and fT3 (P = 0.036). The 197 obese children without substantial weight loss demonstrated no significant changes of thyroid hormones.


CONCLUSIONS
Because fT3 and TSH were moderately increased in obese children and weight loss led to a reduction, the elevation of these hormones seems to be rather a consequence of obesity than a cause of obesity. Because fT3 and TSH were both increased in obesity and thyroid hormones were not associated to lipids, we put forward the hypothesis that there is no necessity for thyroxine treatment.
Reinehr
Thomas
T
Vestische Kinder- und Jugendklinik, University of Witten/Herdecke, Dr. F. Steiner Strasse 5, 45711 Datteln, Germany. T.Reinehr@kinderklinik-datteln.de
de Sousa
Gideon
G
Andler
Werner
W