Preservation of C-Peptide Levels in Children with New-Onset Type 1 Diabetes: A Comparison Based on Body Mass Index

Abstract

Aim: The contemporaneous increase in type 1 diabetes (T1D) and obesity prevalence in children has led to conflicting reports regarding the effects of weight excess on beta-cell function and clinical manifestation of T1D. We aimed to analyze the association between body mass index (BMI) and beta-cell function in a large cohort of new-onset T1D youth. Material and Methods: This study included 204 consecutive children with T1D aged 1-18 years. We retrospectively reviewed the medical data. The preservation of C-peptide was defined as a C-peptide level ≥0.6 ng/mL. Comparisons of variables between groups were made using appropriate statistical procedures. Results: Eighteen percent of children were overweight or obese. Overweight/obesity was associated with significantly higher C-peptide levels at onset [0.57 (0.05-2.99) vs 0.41 (0.05-2.58) ng/ml, p=0.01]. Preservation of C-peptide levels was observed in 67% of patients. Patients with preserved C-peptide levels were older at onset [10.4 (1.9-16.5) vs 7.5 (1.1-17.3) yr, p<0.001], more likely to be pubertal (61.2% vs 22.6%, p<0.001) and had a higher BMI SDS (0.03±1.37 vs -0.67±1.47, p=0.001). The proportion of individuals with preserved C-peptide levels increased with increasing BMI, but the difference did not reach statistical significance (29.9% to 45.9%, p=0.06). While there was a positive correlation between BMI SDS and C-peptide levels (rs=0.24, p=0.001), HbA1c levels negatively correlated with BMI SDS (r=-0.16, p=0.025). Conclusion: Overweight/obesity was present in a significant proportion of the study population. Obese and overweight children had a greater residual beta-cell function at the onset of T1D. It could be speculated that they were diagnosed at an earlier phase of beta-cell damage.