Differences in Type I Diabetes Mellitus of Young Adults with and without Thyroid Autoimmunity

Abstract

This work was intended to study if the coexistence of thyroid and Langerhans islets autoimmunity is associated with a different nature and course of diabetes in young adult diabetic patients. We followed the laboratory and clinical course of diabetes and the thyroid gland status of 47 young adults with Type I diabetes over a 9-year period starting from the onset of diabetes (ranging from 18 to 35 years of age). The patients were divided into subgroup I (with thyroid peroxidase and thyroglobulin antibodies, n = 13), subgroup II (thyroid peroxidase antibody only, n = 10), and subgroup III (without thyroid autoimmunity, n = 24). Out of the 22 females followed, 10 (46 %) and 5 (23 %) were in subgroups with thyroid autoimmunity (TA), I and II, respectively. On the contrary, out of the 25 men followed, 17 (68 %) were in group III. Within the 9 years, insulin secretion nearly ceased (C-peptide < 0.03 nmol/L) in all of the patients of subgroup I and 70 % of subgroup II, but only in 46 % of patients in subgroup III (I : II p < 0.01, I : III, p < 0.01, II : III, p < 0.05). The cumulative incidence of antiGAD > 1 U/mL (CIS, RIA) in subgroup I was higher (92 %) than in subgroups II (80 %) and III (53 %); I : III, p < 0.05. The cumulative incidence of tyrosine phosphatase antibodies (anti-IA2, BRAHMS, RIA) was insignificantly higher in subgroups I and II when compared with subgroup III (62 %, 60 %, and 42 %). The study of organ-specific and systemic autoantibodies showed their highest cumulative incidence in subgroup I, i.e., in patients with the most expressed manifestations of TA and the lowest one in subgroup III, i.e., diabetic patients without TA. Our results suggest that overall thyroid autoimmunity in young adult patients with Type I diabetes was associated not only with female gender, but also with more pronounced Langerhans islets autoimmunity and significantly faster cessation of endogenous insulin secretion; it was associated with therapeutical doses of insulin as well.