Research Information System
ESPE 2022, Roma, Italy, 16 - 17 September 2022
The impact of age, body mass index, and pubertal stage
on C-peptide at type 1 diabetes diagnosis
Emine Ayça Cimbek, Nazım Ercüment Beyhun, Gülay
Karagüzel
Abstract:
Background: Assessment of beta-cell function in type 1 diabetes (T1D) has important implications in both clinical and research settings.
Studies are limited by the lack of adjustments demonstrating the extent to
which puberty influences C-peptide levels. The aim of this study was to evaluate the influence of pubertal stage
as well as age and body mass index (BMI) on multiple C-peptide measures at T1D diagnosis.
Methods: This study included 275 consecutive children aged 1-18 years with newly
recognized T1D. Fasting, prandial, and area under the curve (AUC)
C-peptide, estimated using fasting and prandial C-peptide levels, were
analyzed. In addition, C-peptide increment was also evaluated. Univariate and
multivariable linear regression models were utilized.
Results: Median age at diagnosis was 8.4 (1.1-17.3) years, and mean BMI standard deviation score (SDS) was
-0.4±1.5. Of the patients, 66% were prepubertal. Median fasting and prandial
C-peptide levels at diagnosis were 0.26 (0.05-1.4) 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 (p=0.022
to <0.001). BMI SDS, age, and pubertal stage together explained 19-25% of
the variance of C-peptide measures. There was also a positive correlation
between C-peptide increment and both age and pubertal stage (rs=0.28,
p<0.001 and rs=0.35, p<0.001, respectively).
Conclusions: The findings presented here have implications for the
clinical assessment of young individuals with diabetes and clinical trials
evaluating interventions for preserving beta-cell function in patients with
new-onset T1D. While age and BMI at diagnosis are key variables
associated with beta-cell function, our data set sets the stage for a greater
understanding of the disease process with additional findings regarding puberty.