Probl Endokrinol (Mosk). 2026 May 20;72(2):78-85. doi: 10.14341/probl13645.
ABSTRACT
BACKGROUND: Type 1 diabetes mellitus (T1DM) is a chronic progressive autoimmune disease characterized by destruction of pancreatic betta cells leading to insulin deficiency, measured by C-peptide testing. C-peptide secretion has been studied in diagnostic, prognostic and therapeutic aspects in patients with already manifested T1DM. Insulin secretion assessed by the level of C-peptide at the preclinical stage remains under-studied.
AIM: The aim of the study was to assess the possibility of predicting the development of T1DM in healthy siblings based on dynamic measurements of C-peptide concentration.
MATERIALS AND METHODS: A multicenter prospective longitudinal study involving 532 individuals was conducted. Median follow-up duration was 5.6 years. Group 1 (n=325) included children aged 0-18 years with newly diagnosed T1DM; group 2 (n=201) consisted of healthy brothers and sisters (siblings) who did not develop T1DM until the end of the study; group 3 (n=6) comprised healthy siblings who developed T1DM before the study completion. All participants underwent dynamic testing of blood analysis for C-peptide using solid-phase chemiluminescent immunoassay. RESULTS: In groups 1 and 3, the actual median concentration of baseline C-peptide was below reference values: 0.31 ng/mL [95% CI 0.10-1.39] and 0.56 ng/mL [95% CI 0.32-0.85], respectively. In group 2, it corresponded to the lower limit of reference values: 0.88 ng/mL [95% CI 0.28-2.69]. The observed differences were statistically significant between groups 1 and 2 (χ2 =168.29, df=1, p < 0.001) and between groups 2 and 3 (χ2 =4.2292, df=1, p=0.040). Regression modeling revealed a nonlinear positive relationship between C-peptide concentration and age. At any age category, the median initial C-peptide concentration in groups 1 and 3 was lower than that in group 2 above the average level (“intercept”) characteristic for the cohort of specific age. The association between C-peptide concentration and time since observation onset was statistically significant (p < 0.05) and bidirectional: over time, concentrations decreased in groups 1 and 3 and increased in group 2.
CONCLUSION: Measurement of baseline C-peptide levels followed by dynamic monitoring may serve as an additional screening tool for predicting the risk of T1DM development in healthy siblings.
PMID:42227094 | DOI:10.14341/probl13645
