Epidemiology of type 1 diabetes mellitus in children and adolescents: A 50-year, single-center experience

Background: Global variations in epidemiology of type 1 diabetes mellitus (T1DM) exist. This study is designed to examine demographic and clinical features of T1DM over the past 3 decades as well as evolving trends in epidemiology over last 50 years. Methods: Clinical characteristics of 925 patients with T1DM over last 30 years (1990-2019) were evaluated and compared to previously published data of 477 patients diagnosed between 1969 and 1990 from one of the major referral centers for diabetes in Turkey. Results: Mean age at diagnosis decreased from 9.5 +/- 4.0 to 7.1 +/- 3.6 years within the past 50 years (p < .001). Age at diagnosis peaked at 12-14 years between 1969 and 1990, then fell to 10-11.9 years between 1990 and 1999, and to 4-5.9 years between 2000-2009 and 2010-2019 (p = .005). Although the percentage of patients diagnosed <6 years of age is gradually increasing, the percentage between the ages of 6 and 11.9 years is decreasing, and the percentage diagnosed >= 12 years remained stable. A total of 47.5% of patients had ketoacidosis, 38.2% had ketosis, and 14.3% had only hyperglycemia. 23% of patients had severe diabetic ketoacidosis (DKA), whereas 42% had moderate. Over last 3 decades, there has been no change in frequency of ketoacidosis at presentation, but there has been significant decline in severity (p = .865, and p < .001, respectively). Although the frequency of patients with mild DKA increased over time, frequency of patients with moderate DKA decreased; however, no significant difference was observed among patients with severe ketoacidosis. DKA was more frequent and severe in patients <6 years of age (p = .005, and p < .001, respectively). Conclusion: Age at diagnosis shifted to younger ages in T1DM in the past 50 years. Half of patients had ketoacidosis at diagnosis and frequency of presentation with DKA did not decrease, but severity decreased slightly. Increase in prevalence of T1DM in the younger age group and the fact that half of patients present with DKA indicate that awareness should be increased in terms of early diagnosis and treatment. image