American Diabetes Association
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Age of diagnosis does not alter the presentation or progression of robustly defined adult-onset type 1 diabetes

posted on 2023-02-21, 17:40 authored by Nicholas.J Thomas, Anita.V Hill, Colin.M Dayan, Richard.A Oram, Timothy.J McDonald, Beverley.M Shields, Angus.G Jones, the StartRight Study group



To determine whether presentation, progression and genetic susceptibility of robustly defined adult-onset type 1 diabetes (T1D) are altered by diagnosis age.


We compared the relationship between diagnosis age and presentation, C-peptide loss (annual change in Urine C-peptide Creatinine Ratio (UCPCR)) and genetic susceptibility (T1D genetic risk Score (T1DGRS)) in adults with confirmed T1D in the prospective StartRight study, 1,798 adults with new-onset diabetes. T1D was defined in two ways: ≥2 positive islet-autoantibodies (of GADA, IA-2A, ZNT8A) irrespective of clinical diagnosis(n=385), or 1 positive islet-autoantibody and a clinical diagnosis of T1D(n=180). 


In continuous analysis age of diagnosis was not associated with C-peptide loss for either definition of T1D [p>0.1], with mean(95% CI) annual C-peptide loss in those diagnosed before and after age 35 (median age of T1D defined by ≥2 positive autoantibodies): 39(31-46)% vs 44(38-50)% with ≥2 positive islet-autoantibodies and 43(33-51)% vs 39(31-46)% with clinician diagnosis confirmed by 1 positive islet-autoantibody [p>0.1]. Baseline C-peptide and T1DGRS were unaffected by age of diagnosis or T1D definition [p>0.1]. In T1D defined by ≥2 autoantibodies, presentation severity was similar in those diagnosed before and after age 35: unintentional weight loss 80(95% CI 74-85)% vs 82(76-87)%, ketoacidosis 23(17-29)% vs 19(14-25)% and presentation glucose 21(19-22) mmol/l vs 21(20-22) mmol/l [all p≥0.1]. Despite similar presentation, older adults were less likely to be diagnosed with T1D, insulin treated, or admitted to hospital.  


When adult-onset T1D is robustly defined the presentation characteristics, progression, and T1D genetic susceptibility are not altered by age of diagnosis. 


Care Research Exeter Biomedical Research Centre

Care Research Exeter Clinical Research Facility

Diabetes UK 16/0005529 17/0005624

European Foundation for the Study of Diabetes

National Institute for Health

National Institute of Health x CS-2015-15-018

NIHR x CS-2015-15-018

NIHR Exeter Clinical Research Facility

Wellcome Trust


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