Objectives: To identify proportion of various types of diabetes and differences between type 1 and type 2 diabetes in patients with youth onset diabetes (onset below 25 completed years of age). In addition, concurrent autoimmune diseases in type 1 diabetes were studied in a subset of patients.
Methods: A total of 577 patients (192 girls) with diabetes onset at median age of 14 y (range 1 mo-25 y) with median duration of 1 y (range day of diagnosis- 43 y) were included. Clinical details, investigations and complications were recorded in a proforma. Diabetes was classified using clinical criteria supported by laboratory tests of C peptide and anti GAD-65 antibody in a subset of patients.
Results: Type 1 diabetes accounted for 368/421 (87.4 %) patients with age of onset <18 y and 99/156 (63.5 %) of patients with onset between 19 and 25 y of age. Proportion of type 2 diabetes was 36/421 (8.5 %) and 41/156 (26.2 %) in these two groups. Older age at onset, diabetes in one or both parents, absence of ketosis /weight loss and presence of acanthosis were significant predictors of type 2 diabetes. Hypothyroidism (TSH >10) and biopsy proven celiac disease was found in 11.6 and 9.7 % of type 1 diabetes patients respectively.
Conclusions: Type 1 diabetes is the most common type of diabetes in youth, however, a significant proportion of youth have type 2 diabetes. In these patients a combination of clinical factors, biochemical parameters and course over few months helps to guide the diagnosis.
Keywords: Adolescents; Diabetes mellitus; Etiology; India; Type 1; Type 2; Youth onset.