Objective: To determine the distribution of age of onset of T1DM in an adult cohort of patients with T1DM.

Methods: T1DM patients from an adult academic diabetes center provided informed consent, completed a questionnaire and gave permission for medical record review. Demographics included age, gender and race. T1DM diagnosis was confirmed by history, occurrence of DKA, C-peptide and/or positive T1DM autoantibodies. Patients with diabetes due to pancreatic disease, chemotherapy, genetic syndromes or unclear etiology were not included.

Results: Of the 1167 confirmed cases of T1DM, 563 (48.2%) were male and 604 (51.8%) were female; 107 (9.2%) were African-American and 1060 (90.8%) were Caucasian or other (<1% Asian). Mean age of participants was 46.9 +/- 16.2 years. T1DM was diagnosed at ages <1 to 78 years with mean age at onset of 21.3 +/- 14.4 years. Age at onset of <18 years occurred in 576 participants (49.4%), 18-30 years in 313 (26.8%), and >30 years in 278 (23.8%). Males and females age at onset of T1DM ≥18 years were 53.1% and 48.3% respectively, NS (p=0.11). African-Americans and non-African-Americans diagnosed with T1DM at ≥18 years: 52.3% and 50.5% respectively, NS (p=0.71). In a subset of patients with current age ≥30 (n=971), the mean age of onset of T1DM was 23.2+/-14.8 years.

Conclusion: In this cohort of adults with T1DM, over half of all patients were diagnosed at age ≥18 years, and 23.8% at age >30 years. This trend was consistent across race and gender and more pronounced in the subset with age ≥30 years. These findings challenge historical data that the mean age of onset of T1DM is in childhood. The strength of this dataset is accuracy of age of onset and diagnosis. The major limitation is that it is not population based. Because the reported age at onset of T1DM is highly dependent on the age of the cohort studied, epidemiologic studies of T1DM should include the entire age spectrum. Better awareness of T1DM in adults is needed to provide appropriate medical management and to ensure patient safety.


M. Salam: None. Y. Bao: None. C.J. Herrick: Stock/Shareholder; Spouse/Partner; Cardinal Health. J.B. McGill: Research Support; Self; AstraZeneca. Consultant; Self; Boehringer Ingelheim GmbH. Speaker's Bureau; Self; Aegerion Pharmaceuticals. Consultant; Self; Bayer AG, Dexcom, Inc., Intarcia Therapeutics, Inc.. Speaker's Bureau; Self; Janssen Pharmaceuticals, Inc., MannKind Corporation. Research Support; Self; Novartis Pharmaceuticals Corporation. Consultant; Self; Novo Nordisk A/S. J. Hughes: None.

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