Endocrine Abstracts

Background: Type 1 diabetes mellitus is frequently associated with endocrine autoimmune diseases especially thyroid disorders. These could have a negative impact on glycemic control even if there is no clinical evidence of thyroid dysfunction.

The aim of the study was to evaluate thyroid function in a group of children with type 1 diabetes mellitus (T1DM) and no clinical evidence of thyroid diseases and to determine its impact on glycemic control.

Material and methods: We collected demographic data from 72 children with T1DM and no clinical evidence of thyroid disorders, physical examination data, and laboratory data: glycated hemoglobin, thyroid peroxidase antibodies (TPOAb), TSH. Subclinical hypothyroidism has been defined as TSH above 4.5 μU/ml without clinical evidence of hypothyroidism.

Results: Thirty-eight (52.7%) patients were boys; mean age 10.89±4.26 years, mean span of type 1 DM 3.41±2.56 years. TPOAb were present in 23.6% of patients. Mean glycated hemoglobin was higher in patients with thyroid autoimmunity (9.7%±2.05 vs 8.6%±2.11 (P=0.05)). TSH was significantly higher in patients with thyroid autoimmunity (3.39 vs 2.15 μU/ml; P<0.05). A number of 8 patients of 72 (11%) had TSH over 4.5 μU/ml (range 4.5–5.76 μU/ml) and only one child had TSH under 0.5 μU/ml. Subclinical hypothyroidism was observed in 29.4% (5/17) among patients with thyroid autoimmunity compared with only 5.4% (3/55) in patients without thyroid autoimmunity (P<0.001).

Conclusions: Thyroid autoimmunity was found in 23.6% children with T1DM and no clinical evidence of thyroid disorders. Patients with thyroid autoimmunity had significantly higher glycated hemoglobin and higher TSH versus patients negative for TPOAb. The most frequent subclinical thyroid dysfunction found out was hypothyroidism. Subclinical hypothyroidism was much more prevalent in patients with thyroid autoimmunity.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.