ESPE Abstracts

Background: In recent years, studies have consistently demonstrated higher TSH concentrations in overweight/obese children and adults compared with normal weight individuals, whereas the levels of thyroid hormones in peripheral blood remain within normal range. This euthyroid hyperthyrotropinemia on the background of a worldwide increase in childhood obesity raises the question of whether subjects with this elevated TSH should be treated.

Objective and hypotheses: In this study, we compared a group of overweight/obese children and adolescents to a normal weight age-matched group in order to characterize the thyroid function in correlation with BMI and pubertal status in both males and females.

Method: The study groups included 389 overweight/obese children (BMI z-score>2) and 158 healthy normal-weight children, who served as controls. Mean BMI z-score in pre-pubertal and pubertal subgroups of the overweight/obese children was not significantly different. TSH, T₄ and T₃ were assessed.

Results: Mean serum TSH value of overweight/obese group was higher (2.95 mU/l±1.2) compared to that (2.42 mU/l±1.43) of normal weight group (P<0.0001). In females of both overweight and control groups, serum TSH, T₄ and T₃ concentrations were all lower during puberty compared to the pre-pubertal period. On the contrary, males showed no statistically significant variation in TSH and peripheral thyroid hormone concentrations after initiation of puberty in both overweight and control groups. In overweight/obese pre-pubertal girls and boys, a statistically significant correlation between TSH and BMI was found (coefficients r=0.32, P=0.012 and r=0.47, P<0.001 respectively). This correlation between TSH and BMI was not sustained after initiation of puberty.

Conclusion: Our results confirm the TSH elevation observed in overweight/obese children and furthermore, imply that puberty has an impact on thyroid axis function and may negatively affect the relation between TSH and BMI in overweight/obese children.