Introduction: Individuals with type 1 diabetes (T1D) are at higher risk of developing other autoimmune disease, including autoimmune thyroid diseases (AITD). The incidence of Hashimoto among people with T1D varies between 8 and 50%, depending on gender, age and ethnicity.
Aim: To evaluate prevalence of anti-thyroid peroxidase (anti-TPO) and its correlation to the presence of thyroid dysfunction in children and adults at diagnosis of T1D and in the five-year observation.
Methods: The study included 367 patients (218 children; 149 adults) at T1D onset. Anti-TPO level and thyroid function tests (T4,T3, and TSH) were performed within 5 days of the initial diagnosis of diabetes and during the five-year follow-up period.
Results: At T1D onset, anti-TPO was reported in 18.5% of patients, more frequently in adults than in children (26.2%vs.13.3%, P=0.001). In children, anti-TPO was observed mostly in girls (62.1vs. 37.9%, P=0.047), while there was no gender association in adults (females 56.4% vs. men 34.6%; P=0.754). Positive anti-TPO patients had higher occurrence of GADA (83.8%vs. 70%,P= 0.03) and higher level of its titer [median 38.7 (IQR:5.4-512.4)vs.6.2 (1.1-40.6),P<0.0001]. Whereas, in children higher titer of IAA was observed [6.5 (5.3-8.2)vs. 5.6 (5.0-6.9),(P=0.026)].
Hypothyroidism (HT) at diagnosis of T1D occurred more frequently in adults than in children (9 vs. 2,P=0.009), in 3 positive anti-TPO adults autoimmune hyperthyroidism was noted (elevated titers of anti-TSH-R). Positive anti-TPO adults had higher TSH concentration as opposed to negative anti-TPO group (3.6±0.9vs 1.7±0.9,P=0.026), such an relationship was not observed among children. HT was diagnosed in 41.4% anti-TPO positive children at T1D onset in the five-year follow-up period, significantly more often in girls than in boys (83.3%vs.16.7%). While, only next 15% of adults with initially positive anti-TPO developed HT during the study period. The mean time from T1D diagnosis to HT development was 2.8±1.7 years.
Conclusions: Anti-TPO tended to occur more frequently in adults with newly diagnosed T1D without gender association, whereas in children anti-TPO was observed significantly more often in females. The presence of a positive anti-TPO titer was related to a higher incidence of HT at T1D onset in adults. While, in children, the occurrence of a positive anti-TPO titer at T1D diagnosis was associated with a greater risk of developing HT in 5-year follow-up period. The results of the study confirm the validity of screening for AITD at the time of T1D diagnosis and further thyroid function assessment should be recommended.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology