Factors Associated with Decline of C-peptide in a Cohort of Young Children Diagnosed with Type 1 Diabetes

Abstract

<p><strong>Context: </strong>Understanding factors involved in the rate of C-peptide decline is needed to tailor therapies for type 1 diabetes (T1D).</p><p><strong>Objective: </strong>Evaluate factors associated with rate of C-peptide decline after T1D diagnosis in young children.</p><p><strong>Design: </strong>Observational study.</p><p><strong>Setting: </strong>Academic centers.</p><p><strong>Participants: </strong>57 participants in The Environmental Determinants of Diabetes in the Young (TEDDY) enrolled at 3 months of age and followed until T1D and 56 age-matched children diagnosed with T1D in the community.</p><p><strong>Intervention: </strong>A mixed meal tolerance test was used to measure the area under the curve (AUC) C-peptide at 1, 3, 6, 12 and 24 months post-diagnosis.</p><p><strong>Outcome: </strong>Factors associated with rate of C-peptide decline during the first 2 years post-diagnosis were evaluated using mixed effects models adjusting for age at diagnosis and baseline C-peptide.</p><p><strong>Results: </strong>Adjusted slopes of AUC C-peptide decline did not differ between TEDDY subjects and community controls (p=0.21), although the former had higher C-peptide baseline levels. In univariate analyses combining both groups (n=113), younger age, higher weight and BMI z-scores, female sex, increased number of islet autoantibodies, and IA-2A or ZnT8A positivity at baseline were associated with higher rate of C-peptide loss. Younger age, female sex and higher weight z-score remained significant in multivariate analysis (all p<0.02). At three months after diagnosis, higher HbA1c became an additional independent factor associated with higher rate of C-peptide decline (p<0.01).</p><p><strong>Conclusion: </strong>Younger age at diagnosis, female sex, higher weight z-score, and HbA1c were associated with higher rate of C-peptide decline after T1D diagnosis in young children.</p>