The Association of C-Peptide with BMI at the Diagnosis of Type 1 Diabetes (T1D) in Children Participating in the Diabetes Prevention Trial-Type 1 (DPT-1)

Jay Sosenko, Carmella Evans- Molina, Linda Dimeglio, Lisa E. Rafkin, Yuk-Fun Liu, Jay Skyler, Jerry Palmer

Research output: Chapter in Book/Report/Conference proceedingMeeting abstractpeer-review

Abstract

Since C-peptide is used to estimate residual β-cell function at the diagnosis of T1D, we assessed whether BMI might influence specific C-peptide indices at diagnosis in autoantibody positive children. There were 98 children who progressed to T1D before 18.0 years of age (mean±SD age at diagnosis: 11.3±3.3 years) with 2-hr OGTTs and BMI measurements at diagnosis in DPT-1. The BMI z-score (BMIZ) was used for age and gender standardization. At diagnosis, both fasting and AUC C-peptide correlated with BMIZ (r=0.52, p<0.001 and r=0.34; p<0.001, respectively). C-peptide values were appreciably greater in the highest quartile of BMIZ than in the lowest quartile for both C-peptide measures (fasting C-peptide: 2.16±1.00 ng/ml vs. 0.91±0.56 ng/ml; p<0.001; AUC C-peptide: 488±201 ng/ml vs. 290±148 ng/ml; p<0.001). We also examined the association of the 30-0 minute C-peptide difference (early C-peptide response), previously shown to correlate with the first-phase insulin response, with BMIZ. There was little association between the early C-peptide response and BMIZ (r=0.08; p=0.44). The early C-peptide response values of the highest BMIZ quartile did not differ significantly from the lowest quartile values (1.60±1.31 ng/ml vs. 1.22±0.82 ng/ml, respectively; p=0.22). Among 84 children tested for HbA1c at diagnosis, HbA1c was significantly related to the early C-peptide response (r=0.32, p<0.01), but not to BMIZ (r=0.09, p=0.43). In conclusion, children with greater BMIZ values have higher fasting and AUC C-peptide levels at the diagnosis of T1D. The higher C-peptide levels appear to be indicative of greater insulin insensitivity rather than more remaining β-cell function, since the early C-peptide response is not related to BMIZ. Moreover, HbA1c and BMIZ are not related at diagnosis. If the fasting or AUC C-peptide are used to assess residual β-cell function at diagnosis, estimates could be inflated in children with more adiposity.
Original languageEnglish
Title of host publicationDiabetes
Volume65
EditionSupplement 1
Publication statusPublished - 1 Jun 2016

Fingerprint

Dive into the research topics of 'The Association of C-Peptide with BMI at the Diagnosis of Type 1 Diabetes (T1D) in Children Participating in the Diabetes Prevention Trial-Type 1 (DPT-1)'. Together they form a unique fingerprint.

Cite this