[Value of C-peptide-based insulin resistance index for evaluating correlation between insulin resistance and serum uric acid level in individuals undergoing health examination].

OBJECTIVE: To investigate the value of C-peptide-based insulin resistance index in evaluating the correlation between insulin resistance and serum uric acid (Ua) level in subjects undergoing health examination. METHODS: The data of 46 017 subjects undergoing health examination were retrospectively collected from the Second Medical Center of PLA General Hospital from January, 2017 to December, 2021. The subjects were divided into Ua≤420 µmol/L group and Ua>420 µmol/L group for comparison of HOMA insulin resistance index (HOMA2-IR) and HOMA insulin resistance-C peptide (HOMA2 IR-CP). The correlations of HOMA2-IR and HOMA2 IR-CP with Ua level were analyzed using Pearson correlation analysis and linear regression analysis. Hierarchical interaction analysis was conducted to assess the differences in the association between insulin resistance index and Ua level in different subgroups. The ROC curve was used to evaluate the predictive ability of insulin resistance index for an increased Ua level. RESULTS: The levels of HOMA2-IR and HOMA2 IR-CP were significantly lower in Ua≤420 µmol/L group than in Ua>420 µmol/L group. Univariate Pearson correlation analysis showed a weak correlation of HOMA2-IR with Ua (r=0.262, P<0.001) and moderate correlation of HOMA2 IR-CP with Ua (r=0.409, P<0.001). Multivariate linear regression analysis, after adjustment for confounding factors, demonstrated that HOMA2-IR (R2=0.445, P<0.001) and HOMA2 IR-CP (R2=0.461, P<0.001) were both factors affecting Ua level. Hierarchical interaction analysis showed that the association of insulin resistance index with Ua level varied significantly with gender, age, and glucose metabolism (P<0.001). ROC curve showed that the areas under the curve predicted an increased Ua level by HOMA2-IR and HOMA2 IR-CP were 0.662 and 0.722, respectively. CONCLUSIONS: HOMA2 IR-CP is a more accurate indicator for assessing the correlation between insulin resistance and Ua level.

Predictive role of serum C-peptide in new-onset renal dysfunction in type 2 diabetes: a longitudinal observational study.

Background: Our previous cross-sectional study has demonstrated the independently non-linear relationship between fasting C-peptide with renal dysfunction odds in patients with type 2 diabetes (T2D) in China. This longitudinal observational study aims to explore the role of serum C-peptide in risk prediction of new-onset renal dysfunction, then construct a predictive model based on serum C-peptide and other clinical parameters. Methods: The patients with T2D and normal renal function at baseline were recruited in this study. The LASSO algorithm was performed to filter potential predictors from the baseline variables. Logistic regression (LR) was performed to construct the predictive model for new-onset renal dysfunction risk. Power analysis was performed to assess the statistical power of the model. Results: During a 2-year follow-up period, 21.08% (35/166) of subjects with T2D and normal renal function at baseline progressed to renal dysfunction. Six predictors were determined using LASSO regression, including baseline albumin-to-creatinine ratio, glycated hemoglobin, hypertension, retinol-binding protein-to-creatinine ratio, quartiles of fasting C-peptide, and quartiles of fasting C-peptide to 2h postprandial C-peptide ratio. These 6 predictors were incorporated to develop model for renal dysfunction risk prediction using LR. Finally, the LR model achieved a high efficiency, with an AUC of 0.83 (0.76 - 0.91), an accuracy of 75.80%, a sensitivity of 88.60%, and a specificity of 70.80%. According to the power analysis, the statistical power of the LR model was found to be 0.81, which was at a relatively high level. Finally, a nomogram was developed to make the model more available for individualized prediction in clinical practice. Conclusion: Our results indicated that the baseline level of serum C-peptide had the potential role in the risk prediction of new-onset renal dysfunction. The LR model demonstrated high efficiency and had the potential to guide individualized risk assessments for renal dysfunction in clinical practice.

Exploration of suitable external quality assessment materials for serum C-peptide measurement.

OBJECTIVES: To find suitable external quality assessment (EQA) materials for serum C-peptide, we evaluated the commutability of five types of processed materials. METHODS: Seventy-four individual serum samples and 12 processed samples including three EQA samples currently in use, frozen human serum pools (FHSP), and three other kinds of processed samples were prepared by dissolving WHO International Standard Reagent for C-peptide (WHO ISR 13/146) in three different matrixes: 0.05 % bovine serum albumin, fetal bovine serum and human serum pools. Samples were analyzed using the isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method and six widely used immunoassays. The commutabilities of processed materials were assessed according to the difference in bias approach recommended by the IFCC. And the short- and long-term stability of FHSP samples at different temperatures were also evaluated. RESULTS: Out of the five kinds of processed materials, FHSP samples were commutable on most assays. In contrast, the EQA materials currently in use were only commutable on a few immunoassays. Additionally, processed materials derived from WHO ISR 13/146 were found to be un-commutable on over half of immunoassays. The FHSP samples could be stably stored at 4 and -20 °C for at least 16 days, and at -80 °C for at least 1 year, but at room temperature only for 12 h. CONCLUSIONS: With clarified commutability and stability information, the human serum pool samples along with the developed ID-LC-MS/MS method could be used in the EQA program to promote the comparability among laboratories for C-peptide measurement in China.

An Accurate Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide and Its Use in Harmonization in China.

Background: Serum C-peptide results from various routine methods used in China are highly variable, warranting well-performing methods to serve as an accuracy base to improve the harmonization of C-peptide measurements in China. We developed an accurate isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for serum C-peptide measurement and explored its use in harmonization. Methods: After protein precipitation with ZnSO4 solution, C-peptide was extracted from serum samples by anion-exchange solid-phase extraction and quantified by ID-LC-MS/MS in positive ion mode. The precision and analytical recovery of the ID-LC-MS/MS method were assessed. Seventy-six serum samples were analyzed using the ID-LC-MS/MS method and six routine immunoassays. Ordinary linear regression (OLR) and Bland-Altman (BA) analyses were conducted to evaluate the relationship between the ID-LC-MS/MS method and routine immunoassays. Five serum pool samples assigned using the ID-LC-MS/MS method were used to recalibrate the routine assays. OLR and BA analyses were re-conducted after recalibration. Results: The within-run, between-run, and total precision for the ID-LC-MS/MS method at four concentrations were 1.0%-2.1%, 0.6%-1.2%, and 1.3%-2.2%, respectively. The analytical recoveries for the ID-LC-MS/MS method at three concentrations were 100.3%-100.7%, 100.4%-101.0%, and 99.6%-100.7%. The developed method and the immunoassays were strongly correlated, with all R2 >0.98. The comparability among the immunoassays was substantially improved after recalibration. Conclusions: The performance of the ID-LC-MS/MS method was carefully validated, and this method can be used to improve the harmonization of serum C-peptide measurements in China.

Difference in the early clinical course between children with type 1 diabetes having a single antibody and those having multiple antibodies against pancreatic ß-cells.

Islet-cell associated antibodies are predictive and diagnostic markers for type 1 diabetes. We studied the differences in the early clinical course of children with type 1 diabetes with a single antibody and those with multiple antibodies against pancreatic ß-cells. Sixty-seven children with type 1 diabetes aged less than 15 years diagnosed between 2010 and 2021 were included in the study and subdivided into two subgroups: children who were single positive for either glutamic acid decarboxylase (GAD) antibodies (n = 16) or insulinoma-associated antigen-2 (IA-2) antibodies (n = 13) and those positive for both antibodies (n = 38) at diagnosis. We compared the patients' clinical characteristics, pancreatic ß-cell function, and glycemic control during the 5 years after diagnosis. All clinical characteristics at diagnosis were similar between the two groups. One and two years after diagnosis, children who tested positive for both antibodies showed significantly lower postprandial serum C-peptide (CPR) levels than those who tested positive for either GAD or IA-2 antibodies (p < 0.05). In other periods, there was no significant difference in CPR levels between the two groups. There was a significant improvement in glycosylated hemoglobin (HbA1c) levels after starting insulin treatment in both groups (p < 0.05), but no significant difference in HbA1c levels between the groups. Residual endogenous insulin secretion may be predicted based on the number of positive islet-cell associated antibodies at diagnosis. Although there are differences in serum CPR levels, optimal glycemic control can be achieved by individualized appropriate insulin treatment, even in children with type 1 diabetes.

Changes and significance of triglyceride-glucose index, C-peptide and lipid metabolism in patients with type 2 diabetes mellitus complicated with hyperuricemia / 中国医师进修杂志

Objective:To explore the changes and significance of triglyceride-glucose (TyG) index, C-peptide and lipid metabolism in patients with type 2 diabetes mellitus (T2DM) complicated with hyperuricemia (HUA).Methods:A prospective research method was adopted. One hundred and three patients with T2DM treated in Tongling Hospital of Traditional Chinese Medicine were selected between March 2019 and November 2021, and they were divided into HUA group (34 cases) and non-hyperuricemia (NUA) group (69 cases) according to whether they were complicated with HUA. The general data, fasting blood glucose (FBG), serum uric acid (SUA), serum C-peptide, total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and serum creatinine (SCr) were compared among the patients, and the TyG index was calculated. The relationship between the above different indicators and SUA was analyzed, and the possible risk factors of HUA with T2DM were analyzed.Results:There were no statistical differences in gender, disease course of diabetes and smoking history between HUA group and NUA group ( P>0.05), but the age in HUA group was younger than that in NUA group: (46.71 ± 10.23) years old vs. (58.74 ± 11.22) years old, and the body mass index (BMI) was higher than that in NUA group: (24.48 ± 2.26) kg/m 2 vs. (22.05 ± 2.14) kg/m 2, and the proportion of patients with alcohol drinking history was higher than that in NUA group: 55.88% (18/34) vs. 24.64% (17/69) ( P<0.05). There were no statistically significant differences in the levels of FBG, TC and LDL-C between HUA group and NUA group ( P>0.05), but the TG, TyG index, C-peptide, SUA and SCr were higher in HUA group than those in NUA group: (2.68 ± 0.57) mmol/L vs. (1.57 ± 0.33) mmol/L, 10.58 ± 3.52 vs. 7.03 ± 2.14, (2.59 ± 0.67) μg/L vs. (2.07 ± 0.41) μg/L, (356.74 ± 56.47) μmol/L vs. (319.87 ± 50.92) μmol/L, (72.05 ± 8.31) μmol/L vs. (58.59 ± 8.04) μmol/L, while the HDL-C level was lower than that in NUA group: (1.09 ± 0.33) mmol/L vs. (1.38 ± 0.41) mmol/L ( P<0.05). Pearson correlation results showed that TyG index, C-peptide, TG, LDL-C and SCr were positively correlated with SUA ( r = 0.42, 0.49, 0.41, 0.30 and 0.51; P<0.05), and HDL-C was negatively correlated with SUA ( r = -0.47, P<0.05). Multivariate Logistic regression analysis showed that increased BMI, alcohol drinking, increased TyG index and C-peptide, TG and SCr and reduced HDL-C were risk factors for HUA in patients with T2DM ( P<0.05). Conclusions:The TyG index, serum C-peptide and TG in patients with T2DM complicated with HUA are abnormally increased and are positively correlated with SUA, while HDL-C is decreased and is negatively correlated with SUA. High BMI, alcohol drinking, high TyG index, C-peptide, TG and SCr, and low HDL-C level are risk factors for HUA in patients with T2DM.

Preserved C-peptide secretion is associated with higher time in range (TIR) on intermittently scanned continuous glucose monitoring in Chinese adults with type 1 diabetes.

Objective: To explore the relationship between C-peptide secretion and time in range (TIR) in adult patients with type 1 diabetes. Methods: From December 2018 to December 2020, 76 type 1 diabetes participants were enrolled from the Department of Endocrinology and Metabolism of Peking University People's Hospital. All participants wore intermittently scanned continuous glucose monitoring (isCGM), and insulin dosage was adjusted according to standardized clinical procedures. Subjects were divided into low C-peptide group (<10 pmol/L) and preserved C-peptide group (10-200 pmol/L) based on fasting serum C-peptide levels. Differences of TIR, metrics related to glucose variability and hypoglycemic events were compared. Results: A total of 94,846 isCGM values obtained from 39 male and 37 female participants were analyzed. Individuals with preserved C-peptide secretion had shorter diabetes duration (2.0 (0.5, 10.0) vs 10.0 (3.0, 18.3) years, P = 0.002). TIR was higher in the individuals with preserved C-peptide than those with decreased C-peptide (67.1% (54.2, 75.8) vs 45.5% (33.9, 56.1), P < 0.001), and time above range was significantly lower in those with preserved C-peptide (28.0% (15.6, 42.4) vs 49.4% (39.1, 64.2), P < 0.001). Preserved C-peptide was associated with lower glucose variability, as defined by s.d. (3.0 mmol/L (2.6, 3.4) vs 3.8 mmol/L (3.2, 4.3), P < 0.001) and interquartile range (4.3 mmol/L (3.1, 4.8) vs 5.3 mmol/L (4.5, 6.3), P < 0.001). Metrics related to hypoglycemia were not different between the two groups. Conclusion: Preserved C-peptide secretion was associated with higher TIR and lower glucose variability in Chinese type 1 diabetes adults.

Residual endogenous insulin secretion in Japanese children with type 1A diabetes.

We investigated serum C-peptide immunoreactivity (CPR) levels in registered data from a multi-center collaborative nationwide type 1 diabetes study. The CPR levels were obtained from 576 and 409 children during the early registration (2013/2014) and late observation (2016/2017) periods, respectively. The percentages of children with a CPR < 0.1 or < 0.3 ng/mL increased according to the duration since diagnosis. Among patients with 5 or more years since diagnosis, 69% had a CPR < 0.1 and 95% had a CPR < 0.3 in the early registration period. A significant negative correlation was observed between the HbA1c and the CPR levels, and the HbA1c levels were significantly higher among children with a CPR < 0.1 or < 0.3 than among those with a CPR ≥ 0.6 ng/mL. During the late observation period, the prevalence of a CPR < 0.1 ng/mL was 88% among long-standing patients and 77% among patients aged 18-20 yr. Regarding the characteristics of "Responders" with a sustained CPR ≥ 0.6 ng/mL at 5 or more years since diagnosis, six of the seven were adolescent females; five of the seven had an HLA DR4-DQ4 haplotype. When type 1A diabetes mellitus (T1AD) children transit to adult care centers, most of them may have some difficulty in glycemic control because of the depleted endogenous insulin.

Relationship between fasting serum C-peptide level and heart function in patients with or without diabetes mellitus and chronic heart failure / 中国综合临床

Objective@#To evaluate the relationships between admission fasting serum C-peptide concentration and cardiac function status in chronic heart failure (CHF) patients with or without diabetes.@*Methods@#From July 2017 to December 2018, 262 CHF patients with or without diabetes in the Department of Cardiology of Pudong hospital in Shanghai were analyzed.Their cardiac function was classified as New York Heart Association (NYHA) grade Ⅱ to Ⅳ, and they were divided into diabetes group (80 cases) and non diabetes group (182 cases). At the same time, 62 subjects without diabetes and heart disease were randomly selected as the control group.To analyze the relationship between fasting serum C-peptide level and cardiac function in diabetic and nondiabetic CHF patients.@*Results@#(1)The fasting plasma glucose and serum C-peptide concentrations of diabetes group paitents were(8.7±2.9) mmol/L and(0.78±0.67) nmol/L respectively, the nondiabetes group paitents were(5.8±1.67) mmol/L and(0.56±0.61)nmol/L respectively, the control group were(5.1±0.69) mmol/L and(0.16±0.12)nmol/L respectively.The difference in the three groups was statistically significant(all P<0.001). The levels of fasting blood glucose and serum C-peptide in diabetic group were significantly higher than those in non diabetic group and control group (all P<0.01). The levels of fasting blood glucose and serum C-peptide in non diabetic group were significantly higher than those in control group (P<0.05 or P<0.01). The left ventricular ejection fraction (LVEF) in diabetic group was(44.1±8.3)%, and those in non diabetic group and control group were(46.7±7.2)% and(64.8±3.8)%.The difference in the three groups was statistically significant(<0.001). The LVEF of diabetic group was significantly lower than that of non diabetic group and control group (all P<0.01), and the CRP of diabetic group was (1.39±0.91) mg/L, the N-terminal pro-B-type natriuretic peptide (pro-BNP) was (1 771.3±23.1) ng/L, the hemoglobin was (125.6±16.7) g/L in the diabetic group, and (1.22±0.73) mg/L, (1 659.2±19.3) ng/L, (126.1±16.5) g/L in the non diabetic group, respectively, and (0.85±0.72) mg/L, (87.2±17.2) ng/L, (136.4±15.2) g/L in the control group, respectively.The differences among the three groups were statistically significant (P<0.001). CRP and pro-BNP in the diabetic group and non diabetic group were significantly higher than those in the control group (all P<0.01), and hemoglobin levels were significantly lower than those in the control group(all P<0.01). There were no statistically significant differences in CRP, pro-BNP and hemoglobin between the diabetic group and non diabetic group (all P>0.05). (2) In all patients with heart failure, diabetes mellitus and non diabetes heart failure, the levels of serum C-peptide were (1.05±0.85), (1.17±0.82), (0.99±0.86) nmol/L in NYHA Ⅳ group, and (0.53±0.22), (0.52±0.20), (0.54±0.23) nmol/L in NYHA Ⅲ group, and (0.32±0.09), (0.32±0.11), (0.31±0.09) nmol/L in NYHA Ⅱ group.After adjustment of age, gender, smoking, insulin secretion and hypoglycemic drugs, body mass index, blood pressure, total bilirubin (TBIL), alanine aminotransferase (ALT), creatinine, blood glucose, blood lipid, white blood cell count (WBC) and hemoglobin level by covariance analysis, all patients with heart failure The level of serum C-peptide in NYHA Ⅳ group was significantly higher than that in Ⅲ group (all P<0.01) and Ⅱ group (all P<0.01). In all patients with heart failure and non diabetic heart failure, the level of serum C-peptide in NYHA Ⅲ group was significantly higher than that in Ⅱ group (all P<0.05). There was no significant difference in serum C-peptide between all patients with heart failure, diabetes mellitus and non diabetes heart failure (all P>0.05) (3) Using multiple linear regression analysis, the adjustment factors included age, gender, smoking, BMI, blood pressure, TBIL, alt, creatinine, blood glucose, blood lipid, WBC and hemoglobin levels.The results showed that the serum C-peptide level was positively correlated with pro-BNP in all patients with heart failure, diabetes and non diabetes heart failure (β: 0.006, 95%CI -0.016-0.028 , P=0.007; β: 0.117, 95%CI-0.042-0.277 , P=0.006; β: 0.411, 95%CI-0.149-0.971 , P=0.023), negatively correlated with LVEF(β: -0.122, 95%CI-0.285-0.041, P=0.004; β: -0.008, 95%CI-0.032-0.016, P=0.010; β: -0.065, 95%CI-0.139-0.011, P=0.036).@*Conclusion@#The level of fasting serum C-peptide was significantly increased in patients with CHF and non-diabetic patients, and was related to the severity of heart failure.

Serum C-peptide as a key contributor to lipid-related residual cardiovascular risk in the elderly.

OBJECTIVES: The serum levels of C-peptide, an important risk factor for cardiovascular disease (CVD), increase with age. This study aimed to investigate the association between serum C-peptide and increased risk for CVD with altered lipid metabolism in the elderly. METHODS: This was a population-based cross-sectional study that included 3091 elderly participants aged ≥65 years. Serum C-peptide and lipid levels were measured according to standard protocols. Sampling weights were used to estimate the characteristics of study participants. Stratified analysis of covariance was used to evaluate the changes in the serum lipid levels according to quartiles of serum C-peptide levels, and the linear trend was assessed using a linear model. The logistic regression model was carried out to determine the association between the serum C-peptide levels and serum lipid levels. RESULTS: The results of the analysis of covariance stratified by sex and serum insulin level showed that the serum triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels were significantly associated with changes in the serum C-peptide levels, independent of the serum insulin level. The logistic regression analyses indicated that the serum C-peptide levels were positively associated with the serum TG levels, and negatively associated with the serum HDL-C levels. A significant dose-response association was obtained in both men and women. CONCLUSIONS: Serum C-peptide levels were strongly associated with increased serum TG and reduced HDL-C levels in the elderly. Our results suggest that serum C-peptide increases the risk of CVD via a pathway that increases TG or decreases HDL-C levels.

Independent association between serum C-peptide levels and fat mass-to-lean mass ratio in the aging process.

AIM: The changes in body composition and biomarker levels that occur during the aging process are complex and remain poorly understood. The present study aimed to evaluate changes in serum C-peptide levels and fat mass-to-lean mass ratio (FM/LM ratio) with increasing age, and to explore the associations between serum C-peptide levels and FM/LM ratio. METHODS: This was a population-based cross-sectional study that included 3912 participants aged 30-85 years. Body composition was measured using dual-energy X-ray absorptiometry. Analysis of covariance was used to evaluate how the serum C-peptide level and FM/LM ratio change with increasing age, as well as how the FM/LM ratio changes in line with increasing serum C-peptide level. A multiple linear regression analysis was carried out to determine the association between serum C-peptide level and FM/LM ratio. RESULTS: Analysis of covariance showed that serum C-peptide levels, and most regional FM/LM ratios tended to increase in line with increasing age. Total fat mass, total lean mass, percentage total fat mass and total FM/LM ratio were significantly elevated, and percentage total lean mass decreased significantly with increasing serum C-peptide levels in both men and women. Multiple linear regression analysis showed that serum C-peptide level was strongly associated with the total FM/LM ratio. CONCLUSIONS: The findings showed that both serum C-peptide level and FM/LM ratio increased with increasing age, and the serum C-peptide level was closely associated with changes in the total FM/LM ratio.

Associations of serum C-peptide level with body fat distribution and ever stroke in nondiabetic subjects.

BACKGROUND: Although elevated serum C-peptide level as an indicator of insulin resistance increases the obesity-associated risk of cardiovascular disease among diabetic patients, evidence indicating that serum C-peptide level is associated with stroke in nondiabetic subjects is limited. The aim of this study is to evaluate the association between serum C-peptide level and ever stroke in nondiabetic subjects and investigated the associations of serum C-peptide level with body fat distribution and stroke events among nondiabetic subjects. METHODS: This study was a population-based cross-sectional study that included 7030 participants aged 12-85 years. Body fat distribution was determined by dual-energy X-ray absorptiometry. Serum C-peptide level was measured using the radioimmunoassay method. The association between serum C-peptide level and body fat distribution was evaluated by multiple linear regression models. Logistic regression analysis was performed to calculate the odds ratio (OR) of serum C-peptide level being associated with ever stroke. RESULTS: A total of 103 nondiabetic subjects reported having a stroke. Logistic regression analysis revealed a high-serum C-peptide level significantly associated with ever stroke among nondiabetic subjects (OR: 3.71, 95% confidence interval: 1.78-7.75). Meanwhile, in multiple linear regression analysis, serum C-peptide level was positively associated with total and regional fat distribution among nondiabetic subjects. CONCLUSION: The serum C-peptide level is strongly associated with the ever stroke in nondiabetic subjects and significantly associated with total and regional body fat distribution.

Endogenous insulin secretion even at a very low level contributes to the stability of blood glucose control in fulminant type 1 diabetes.

Fulminant type 1 diabetes is characterized by almost complete ß-cell destruction, resulting in scarce insulin secretion. In the present study, we aimed to clarify clinical features related to serum C-peptide levels measured by a high sensitivity method, chemiluminescent enzyme immunoassay, in 12 patients with fulminant type 1 diabetes. Serum C-peptide was detected (0.007-0.10 nmol/L) in four patients and was not detected in eight patients. A negative correlation was observed between serum C-peptide levels and daily dosages of insulin (P < 0.01). The patients with detectable C-peptide showed a significantly lower M-value than those without (P = 0.01). In conclusion, our present results suggest that even very low levels of endogenous insulin secreting capacity can improve daily dosages of insulin and stabilize blood glucose levels. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.0059.x, 2010).

Study on the association between the different levels of C-peptide of type 2 diabetes and colorectal cancer risk / 中国糖尿病杂志

To study on the association between the different levels of C-peptide of type 2 diabetes and colorectal adenoma and cancer risk.We detected the concentration of serum C-peptide in 45 type 2 diabetes who were diagnosed as colorectal adenoma and cancer.It showed that serum C-peptide level was higher in type 2 diabetes with colorectal adenomas and cancer than without colorectal adenomas and cancer.The serum C-peptide level may have relationship with colorectal adenomas and cancer.