1453-P: Islet Autoantibody–Positive General Population Individuals Have Smaller Pancreas Volume Compared with Control Individuals

Introduction & Objective: Patients with type 1 diabetes (T1D) have a decline in pancreatic volume (PV) after onset. Previous studies of PV prior to onset have focused on islet autoantibody positive (AAb+) first-degree relatives (FDR) of patients with T1D who have decreased PV. Nothing is known about PV in AAb+ individuals identified from the general population.

Methods: We analyzed 10 individuals who were identified through general population screening to be multiple AAb+, had a recent oral glucose tolerance test (OGTT) and MRI through the Multicenter Assessment of the Pancreas in T1D (MAP-T1D) study. We compared PV index (PVI) of AAb+ general population individuals to multiple AAb+ FDR (n=78; 40 Stage 1, 26 Stage 2, 12 unknown Stage), individuals with T1D (n=93), and control individuals without T1D (n=90). PVI is normalized for weight which accounts for potential confounding from age or sex.

Results: Most AAb+ general population individuals were male (8/10) and non-Hispanic white (9/10). Most (8/10) were Stage 1, and 2 were Stage 2 T1D. Age at MRI was 15.6 ± 2.8 years with a mean HbA1c 5.3 ± 0.3 %, fasting glucose 87 ± 5 mg/dl and 2-hour OGTT glucose 103 ± 32 mg/dl. AAb+ general population individuals had a lower PVI 0.75 ± 0.17 ml/kg compared to control individuals 0.96 ± 0.25 ml/kg (p=0.03). The PVI of AAb+ general population individuals was similar to that of AAb+ FDR 0.85 ± 0.26 ml/kg (p=0.21). Individuals with T1D had a lower PVI 0.60 ± 0.24 ml/kg than AAb+ FDR (p<0.0001) but not AAb+ general population individuals (p=0.14).

Conclusion: AAb+ general population individuals and AAb+ FDR individuals have smaller PVI compared to control individuals without T1D. Individuals with T1D have a smaller PVI than AAb+ FDR. More study on pancreas size prior to T1D onset may help inform future prediction and prevention studies.