Thyroid Function and Obesity in Children and Adolescents

Abstract

The aim of this retrospective study was to investigate the frequency of thyroid dysfunction as assessed by TSH, T3 and T4 in a large cohort of 290 obese and 280 healthy children. In addition, thyroid autoantibodies were measured in random subgroups of 123 obese and 80 control children, iodine excretion in 50 and thyroid volume in 23 of the obese children. Elevated TSH levels (>4 U/l) were found in 22 obese children (7.5%), but only in one control (0.3%). The medians of TSH and T3 concentrations were normal, but significantly higher in the obese group than in the controls, while T4 levels did not differ. The prevalence of positive thyroid autoantibodies was increased in the obese children, for the most part in those with elevated TSH. There was no evidence for iodine deficiency as a cause of the average increase of TSH. We conclude that in childhood obesity TSH and T3 levels are significantly increased; in most cases, however, these increases are not accounted for by thyroid autoimmunity or iodine deficiency. As a consequence, TSH elevations with normal thyroid hormone levels in obese children don’t need any thyroxine treatment, if thyroid disorders were definitely excluded beforehand.

Thyroid hormones and BMI in obese children: One year follow up results

“…Autoimmune thyroiditis has been expressed as a rare reason of elevated TSH in childhood obesity [4,15]. Dekelbab et al, detected 3% autoimmune thyroiditis in their study with obese and non obese children with high TSH [5]; Grandone et al's study result was 7% in 938 obese children and adolescents [9]; in our study none of the children were positive for thyroid autoantibodies.…”

“…Despite the results of some studies, a direct relationship between elevated TSH levels and obesity, as well as lipid profile and weight changes in children has not been established yet [3][4][5][6][7][8].…”

MECHANISMS IN ENDOCRINOLOGY: The crosstalk between thyroid gland and adipose tissue: signal integration in health and disease

“…Similar data, indicating a higher prevalence of elevated serum TSH, were found both in European and North American populations when obese children were compared with normal-weight controls. These higher TSH levels were not related to autoimmune thyroiditis, iodine deficiency, or signs and symptoms of hypothyroidism (121,122). Whether the raised serum levels of TSH in childhood obesity are an adaptive phenomenon, aimed at increasing the metabolic rate in the attempt to prevent further weight gain, or indicate subclinical hypothyroidism, or may be thyroid hormone resistance, is still debated.…”

“…In the study by Marzullo et al (66), which included patients younger than 50 years with moderate or severe obesity (grades II and III), a twofold greater prevalence of TPOAb (17%) was found compared with control subjects (7.6%, P!0.01). In order to explain the greater prevalence of TPOAb in obese individuals, an increased presentation of thyroid antigens to the immune system, possibly resulting from TSH stimulation of thyroid cells, was postulated, albeit not proven (121). At variance with these findings, in the study by Rotondi et al (64), which was restricted to morbid obesity (grade III), patients with increased serum levels of TSH had a low prevalence of TPOAb and did not display the high female-to-male ratio that is typical of thyroid autoimmunity.…”

Subklinik Hipotroidi Çocuklarda Egzojen Obeziteyi Artırıyor mu?

“…They thought that short statured children as a control group might be effect the results (15) Also we enrolled short children as a control group in our study, we determined statistically significantly lower peak TSH values in obese group and no difference in basal TSH levels. In different studies, basal TSH levels (within normal ranges) of obese children were reported to be significantly higher than control group (6,7,(19)(20)(21)(22). In our study there was no difference between control and obese group with respect to basal TSH levels but peak and delta TSH levels of control group were significantly higher than obese subjects (p=0.04, p= 0.021 respectively).…”