Pubertal stage significantly and independently impacts C-peptide levels at type 1 diabetes diagnosis along with body mass index and age

Eur J Pediatr. 2025 Mar 1;184(3):219. doi: 10.1007/s00431-025-06046-3.

Abstract

Assessment of beta-cell function in type 1 diabetes (T1D) has important implications in both clinical and research settings. Studies demonstrating the extent to which puberty influences C-peptide levels are scarce. The aim of this study was to evaluate the influence of pubertal stage, along with age and body mass index (BMI), on multiple C-peptide measures at T1D diagnosis. This study included 275 consecutive children aged between 1 and 18 years with newly diagnosed T1D. Fasting, prandial, and area under the curve (AUC) C-peptide, estimated using fasting and prandial C-peptide levels, were analyzed. Generalized linear regression models were utilized. Median age at diagnosis was 7.9 (1.1-17.3) years, and mean BMI standard deviation score (SDS) was - 0.4 ± 1.4. Of the patients, 66% were prepubertal. Median fasting and prandial C-peptide levels at diagnosis were 0.26 (0.05-1.8) ng/mL and 0.43 (0.05-3) ng/mL, respectively. Fasting C-peptide was almost perfectly correlated with prandial C-peptide (rs = 0.80, P < 0.001). Fasting, prandial, and AUC C-peptide were positively related with BMI SDS, age, and pubertal stage at diagnosis (P < 0.001 for all). All the associations persisted when the variables were included as independent variables in regression models.

Conclusions: Pubertal stage significantly and independently impacts C-peptide levels at T1D diagnosis along with body mass index and age. The adjustments demonstrating the extent to which puberty influences C-peptide levels in new-onset T1D are presented. Our observations underline the existence of distinct endotypes of T1D characterized by differing immunopathological courses.

What is known: • Throughout the evaluation of beta-cell function at T1D diagnosis, it is essential to consider the factors influencing C-peptide levels.

What is new: • While age and BMI at diagnosis are associated with beta-cell function, our findings set the stage for a greater understanding of the disease process with additional findings regarding puberty, supporting the existence of endotypes of T1D.

Keywords: Age; Body mass index; C-peptide; Children; Endotypes; Puberty; Type 1 diabetes.

MeSH terms

  • Adolescent
  • Age Factors
  • Body Mass Index*
  • C-Peptide* / blood
  • Child
  • Child, Preschool
  • Diabetes Mellitus, Type 1* / blood
  • Diabetes Mellitus, Type 1* / diagnosis
  • Diabetes Mellitus, Type 1* / physiopathology
  • Female
  • Humans
  • Infant
  • Linear Models
  • Male
  • Puberty* / physiology

Substances

  • C-Peptide