Characteristics of childhood and adult-onset type 1 diabetes in a multi-ethnic population.

Objective: To compare patients with classic type 1 diabetes (T1D) diagnosed in childhood and adulthood regarding clinical presentation, GADA and HLA DR B1*03/04 prevalence in a multi-ethnic population.

Methods: We studied 83 Brazilian patients with classic T1D divided in 2 groups: (1) diagnosed before 20 years old (n=42); (2) diagnosed at age 20 and up (n=41). All were interviewed and blood was sampled for GADA measurement and HLA DR B1 typing.

Results: The study population comprised 52 women and 31 men, 52 white and 31 non-white individuals with mean age of 29.94 (+/-10.95) years and mean disease duration of 10.37 (+/-7.37) years. The mean age at onset in groups 1 and 2 were, respectively, 11.48 and 27.2 years old. There were no significant differences between groups regarding diabetic ketoacidosis at presentation. A longer symptomatic period preceding the diagnosis was observed in group 2 (p=0.039). The prevalence of GADA and HLA DR B1*03/04 was similar between groups. HLA DR B1*13 was significantly more common in the group 1 (p=0.024). GADA was more prevalent among patients with HLA DR B1*03 (p=0.02).

Conclusion: In this study, T1D diagnosed in adulthood was associated with longer symptomatic period preceding diagnosis and lower prevalence of HLA DR B1*13, but there were no differences regarding ketoacidosis as a form of disease presentation, GADA (+) or HLA DR B1* 03/04.