1318-P: Characteristics of Autoimmune Thyroid Disease in African American and Caucasian Children with Type 1 Diabetes Mellitus

Background: Patients with type 1 diabetes mellitus (T1DM) are at increased risk of autoimmune thyroid disease (AIT). In the pediatric age group, the prevalence of AIT varies across a wide range (3-50%), depending on the population studied. There is very limited data describing the association of T1DM and AIT disease in African-American (AA) children.

Objective: Characterize the association between T1DM and AIT in AA and Caucasian children presenting to the same medical center.

Methods: After IRB approval, the medical records of 130 AA and 130 Caucasian children with T1DM presenting to the Children’s Hospital of Michigan were reviewed. Data collected included age, gender, ethnicity, presence of AIT evidenced by positive anti-TPO or anti-TG antibodies, TSH, free T4, anti-islet, anti-insulin and anti-GAD antibodies. Comparison was drawn between the two ethnicities in regards to the prevalence of AIT as well as predisposing factors for the onset of AIT.

Results: 12.3% of AA with T1DM developed AIT versus 23.8% of Caucasian. This difference was statistically significant with a p-value of 0.023. In the Caucasian group, female was a risk factor for developing AIT (37.9% in females vs. 12.5% in males, p-value 0.001) while gender was not a significant risk factor for AA patients (p-value 0.790). The presence of anti-insulin antibodies was a risk factor for Caucasians (p-value 0.024) but not for AAs (p-value 0.185). The survival analysis showed mean time for onset of AIT in AA with T1DM is 15.1 years vs. 11.7 years in Caucasians (Log Rank p-value 0.025).

Discussion: Our study shows a significantly lower prevalence AIT in AA compared to Caucasian children with T1DM. Female gender and anti-insulin antibody are risk factors for Caucasians but not in AAs. Differences could be secondary to different genes implication given the different genetic background. Further investigation can lead to a better understanding of T1DM and thyroid autoimmunity in the AA population.