Relative Pancreas Volume Is Reduced in First-Degree Relatives of Patients With Type 1 Diabetes.

Objective: Pancreas size is reduced in patients at type 1 diabetes onset and in autoantibody (AAB)-positive donors without diabetes. We sought to determine whether pancreas volume (PV) imaging could improve understanding of the loss of pancreas size in first-degree relatives (FDRs) of patients with type 1 diabetes. We also examined relationships among PV, AAB status, and endocrine and exocrine functions.

Research Design And Methods: We conducted a cross-sectional study that included five groups: AAB control subjects (no diabetes and no first- or second-degree relatives with type 1 diabetes) ( = 49), AAB FDRs ( = 61), AAB FDRs ( = 67 total: = 31 with a single positive AAB [AAB single] and = 36 with multiple positive AABs [AAB multiple]), and patients with recent-onset type 1 diabetes (<1 year) ( = 52). Fasting subjects underwent 1.5T pancreatic MRI, and PV and relative PV (RPV) (PV-to-BMI ratio) were analyzed between groups and for correlations with HbA, C-peptide, glucose, and trypsinogen.

Results: All FDR groups had significantly lower RPV adjusted for BMI (RPV) than control subjects (all < 0.05). Patients with type 1 diabetes had lower RPV than AAB FDR ( < 0.0001) and AAB multiple ( ≤ 0.013) subjects. Transformed data indicated that trypsinogen levels were lowest in patients with type 1 diabetes.

Conclusions: This study demonstrates, for the first time, all FDRs having significantly smaller RPV compared with AAB control subjects. Furthermore, RPV was significantly lower in patients with recent-onset type 1 diabetes than in the AAB FDR and AAB multiple groups. As such, RPV may be a novel noninvasive biomarker for predicting progression through stages of type 1 diabetes risk. This study highlights the potential paracrine relationships between the exocrine and endocrine pancreas in progression to type 1 diabetes in subjects at risk.