β Cell dysfunction exists more than 5 years before type 1 diabetes diagnosis

Area of Science:

• Endocrinology
• Immunology
• Metabolic disease research

Background:

• The precise timing and progression of beta cell dysfunction in type 1 diabetes (T1D) development remain incompletely understood.
• Understanding these patterns is crucial for identifying individuals at high risk and developing timely interventions.

Purpose of the Study:

• To investigate the duration and patterns of beta cell dysfunction in individuals who develop T1D.
• To compare metabolic profiles of autoantibody-positive (aAb+) individuals who progress to T1D at different rates.

Main Methods:

• Compared oral glucose tolerance test (OGTT)-derived metabolic measures in autoantibody-positive (aAb+) progressors (≥5 years and <5 years to T1D) versus autoantibody-negative (aAb-) relatives.
• Analyzed baseline and longitudinal data from the TrialNet Pathway to Prevention study.

Main Results:

• At baseline, progressors already showed impaired beta cell function (lower C-peptide) and poorer glucose control compared to aAb- relatives.
• In progressors with ≥5 years to T1D, metabolic measures were stable until approximately 2 years before diagnosis, then accelerated decline was observed.
• The final 3 years leading up to T1D diagnosis showed nearly identical patterns of metabolic decline in both fast (<5 years) and slow (≥5 years) progressors.

Conclusions:

• Beta cell dysfunction can precede T1D diagnosis by over 5 years in some autoantibody-positive individuals.
• Metabolic decline patterns are uniform in the final 3 years before T1D diagnosis, irrespective of the overall progression rate.