Thyroid autoimmunity in Egyptian children and adolescents with type1 diabetes : [pilot study]

الملخص EN

Objective : The aim of the present case control study was to detect the frequency of thyroid autoimmunity and thyroid dysfunction in a group of type 1 diabetics, randomly selected from the Diabetic Endocrine Metabolic Pediatric Unit at the Children's Hospital of Cairo University.

Also, to study possible epidemiological risk factors, including family history of autoimmune disease, parental consanguinity, age, sex and duration of diabetes; and to suggest a protocol for screening for thyroid dysfunction in type 1 diabetics.

Subjects and Methods : This study included 52 children and adolescents with type 1 diabetes and 32 healthy age- and sex-matched control children.

All diabetics and control (52 diabetics and 30 control) were subjected to full history taking, clinical examination and laboratory testing for thyroid function tests (FT3, FT4 and TSH) and thyroid antibodies (antithyroid peroxidase and anti-thyroglobulin antibodies).

In addition, anti-TSH receptor antibody was done for diabetics with goiter (18 / 52).

The arithmetic mean of HbAl values for the year preceding the study was calculated.

Results: laboratory evidence of thyroid autoimmunity was found in 12 / 52 (23 %) of the diabetic group compared to 1 / 30 (3 %) in the control group (p = 0.0001), in the form of positive anti-thyroid antibody titre in 6 diabetics and borderline titre in another 6.

Subclinical hypothyroidism was found in 2 / 52 diabetics (3.8 %).

All 12 diabetics with thyroid autoimmunity were above 10 years of age and pubertal, and only 8 of them had goiter.

Diabetics with positive or borderline thyroid antibody titre, compared to those with negative titre, had significantly higher levels of median TSH, anti-TPO and anti-TG antibodies but comparable median FT3, FT4, age, duration of diabetes, height SDS and mean HbAl.

Also, clinical goiter and family history of autoimmune disease were significantly more frequent in the group with thyroid autoimmunity.

A significant positive correlation was found between TSH and anti-TG Ab and between TPO-Ab and TG-Ab, and negative correlation between TSH and T4.

Conclusion : Diabetics have significantly higher prevalence of thyroid autoimmunity i compared to non-diabetic control children.

To detect subclinical hypothyroidism, diabetics should be screened yearly even in absence of goiter.

Also, if a positive family history is obtained, a high index of suspicion for thyroid autoimmunity and possible dysfunction should be considered.

We, therefore, recommend screening of all type 1 diabetics by TSH at diagnosis and yearly thereafter, and thyroid antibodies (anti-TG and anti-TPO) can be done mainly in those with thyroid profile suggesting dysfunction to verify etiology.