Association of serum C-peptide concentrations with cancer mortality risk in pre-diabetes or undiagnosed diabetes

The Association of Empirical Dietary Index for Hyperinsulinemia with the Risk of Cancer and Cancer Mortality: A Meta-analysis of Observational Studies

This meta-analysis aimed to assess the association between the empirical dietary index for hyperinsulinemia (EDIH) and cancer mortality risk. We performed a comprehensive search across the online literature up to November 2022 databases. Then, hazard ratio (H.R.) and 95% confidence intervals (CI) were extracted. A total of 14 and seven cohort studies that reported H.R. for the risk of cancer incidence and cancer mortality respectively were included. The pooled H.R. (95% CI) of the association between EDIH and cancer incidence was 1.13 (1.05-1.23) in overall meta-analyses, 1.15 (1.08-1.22) in female subgroups, 1.27 (1.14-1.41) in digestive cancer subgroups, and 1.15 (1.07-1.24) in breast cancer subgroups. Also, the pooled H.R. (95% CI) of the association between EDIH and incidence of cancer mortality was 1.19 (1.13-1.26) in overall meta-analyses, 1.23 (1.13-1.34) in males, 1.18(1.10-1.28) in females, and 1.20 (1.13-1.27) in studies conducted on all cancers as an outcome. Our findings revealed that a higher EDIH was significantly associated with an increased risk of cancer incidence, particularly in females, digestive cancers, and breast cancer. Also, a higher EDIH score was related to a higher risk of cancer mortality overall in both male and female subgroups and with all cancers.

HOMA-IR as a predictor of Health Outcomes in Patients with Metabolic Risk Factors: A Systematic Review and Meta-analysis

INTRODUCTION

There exists clinical interest in the following question: Is there an association between HOMA-IR and the risk of developing metabolic diseases?

AIMS

Assessing the association between high values of HOMA-IR with the incidence of T2DM, MACE, essential hypertension, dyslipidemia, NASH, and cancer in healthy participants and participants with a component of metabolic syndrome.

METHODS

Databases were searched by an experienced librarian to find eligible studies. Observational cohort studies enrolling healthy adults and adults with metabolic syndrome components that evaluated HOMA as a marker of IR were considered for inclusion. Eligibility assessment, data extraction and risk of bias assessment were performed independently and in duplicate. Baseline characteristics of patients, cutoff values of HOMA-IR to predict metabolic events were extracted independently and in duplicate.

RESULTS

38 studies (215,878 participants) proved eligible. A higher HOMA-IR value had a significant effect on the risk of developing T2DM (HR 1.87; CI 1.40-2.49), presenting non-fatal MACE (HR 1.46; CI 1.08-1.97) and hypertension (HR 1.35; CI 1.15-1.59). No association was found regarding cancer mortality and fatal MACE with higher HOMA-IR values, there was not enough information to carry out a meta-analysis to establish an association between higher values of HOMA with cancer incidence, dyslipidemia, and NASH.

CONCLUSIONS

High values of HOMA were associated with an increased risk of diabetes, hypertension, and non-fatal MACE; yet, not for cardiovascular or cancer mortality. More research is needed to determine the value of the HOMA index in metabolic and cardiovascular outcomes.

PROSPERO REGISTRATION NUMBER

CRD42020187645.

Plasma C-Peptide and Risk of Developing Type 2 Diabetes in the General Population

C-peptide measurement may represent a better index of pancreatic β-cell function compared to insulin. While insulin is mainly cleared by liver, C-peptide is mainly metabolized by kidneys. The aim of our study was to evaluate the association between baseline plasma C-peptide level and the development of type 2 diabetes independent of glucose and insulin levels and to examine potential effect-modification by variables related to kidney function. We included 5176 subjects of the Prevention of Renal and Vascular End-Stage Disease study without type 2 diabetes at baseline. C-peptide was measured in plasma with an electrochemiluminescent immunoassay. Cox proportional hazards regression was used to evaluate the association between C-peptide level and type 2 diabetes development. Median C-peptide was 722 (566-935) pmol/L. During a median follow-up of 7.2 (6.0-7.7) years, 289 individuals developed type 2 diabetes. In multivariable-adjusted Cox regression models, we observed a significant positive association of C-peptide with the risk of type 2 diabetes independent of glucose and insulin levels (hazard ratio (HR): 2.35; 95% confidence interval (CI): 1.49-3.70). Moreover, we found significant effect modification by hypertension and albuminuria (p < 0.001 and p = 0.001 for interaction, respectively), with a stronger association in normotensive and normo-albuminuric subjects and absence of an association in subjects with hypertension or albuminuria. In this population-based cohort, elevated C-peptide levels are associated with an increased risk of type 2 diabetes independent of glucose, insulin levels, and clinical risk factors. Elevated C-peptide level was not independently associated with an increased risk of type 2 diabetes in individuals with hypertension or albuminuria.

Effect of Dietary Insulinemia on All-Cause and Cause-Specific Mortality: Results From a Cohort Study

Background: Insulin response to diet might predict the risk of mortality; however, the evidence is limited. We prospectively evaluated the link between the dietary hyperinsulinemia index (DHI) and dietary insulin resistance index (DIRI) with all-cause and cause-specific (cardiovascular disease [CVD] and cancer) mortality.Methods: The National Health and Nutrition Examination Survey (1999-2010) database was used. Vital status through December 31, 2011, was ascertained. Stepwise linear regression models consisted of 39 macro/micronutrients applied, and fasting plasma C-peptide for the DHI and triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-C) for the DIRI were used. Adjusted Cox regression (followed by propensity score matching) was performed to determine the hazard ratios (HRs) and 95% confidence interval (95% CIs).Results: Overall, 22,246 participants were included (mean age = 47.8 years; 48.9% men). There was a significant increasing risk of mortality across the quartiles of DHI, i.e., participants with a highest score of DHI (Q4) had a greater risk of all-cause (HR: 1.21, 95% CI: 1.17-1.26), CVD (HR: 1.17, 95% CI: 1.07-1.29), and cancer (HR: 1.15, 95% CI: 1.08-1.23) mortality compared with the first quartile (Q1; p < 0.001 for all comparisons). Similarly, participants in the highest DIRI quartile (Q4) had 23% and 31% higher risk of all-cause and CVD mortality, respectively, compared with Q1, while the association between cancer mortality and DIRI was non-significant (HR: 0.88, 95% CI: 0.35-2.61).Conclusions: These findings highlight, for the first time, the detrimental role (association) of insulinemia and insulin resistance potential of diet on all-cause and cause-specific mortality. Our findings support the role of C-peptide and TG/HDL-C ratio as cost-effective and practical biomarkers in clinical settings. These results need to be confirmed to establish their implications.

Relationship between HbA1c and cancer in people with or without diabetes: a systematic review

AIM

To identify the relationship between HbA1c and cancers in people with or without diabetes.

BACKGROUND

Cancer is a major public health problem, accounting for 8.2 million deaths worldwide in 2012. HbA1c level has been associated with the risk of developing certain cancers, although the existing evidence is conflicting.

METHODS

EMBASE, MEDLINE, CINAHL and the Cochrane Library were searched. Eligible articles included randomized controlled trials, cohort studies, case-control studies, systematic reviews and meta-analyses. Participants of either sex, with or without Type 1 or 2 diabetes, were included. The studies were assessed using the Scottish Intercollegiate Guidelines Network (SIGN) criteria by two independent assessors. No meta-analysis was performed because of the heterogeneity of results.

RESULTS

A total of 19 studies from 1006 met the inclusion criteria, of which 14 were cohort studies and five were nested case-control studies. Eight studies investigated outcomes for all cancer sites. Four of these studies reported that higher HbA1c levels were associated with higher incidence and/or mortality risk for all cancers. One study observed a U-shaped relationship between HbA1c and cancer incidence and mortality. Increasing HbA1c levels were associated with increasing risk of developing colorectal, pancreatic, respiratory and female genital tract cancers. No increased risk was observed for breast cancer, gastrointestinal or urological malignancies.

CONCLUSION

HbA1c appears to be associated with cancer incidence and/or cancer mortality, but further studies are needed to fully understand the complex relationship between HbA1c and cancer.

Post-partum plasma C-peptide and ghrelin concentrations are predictive of type 2 diabetes in women with previous gestational diabetes mellitus

BACKGROUND

Women with previous gestational diabetes mellitus (pGDM) are at increased risk of developing type 2 diabetes later in life. The aim of this study was to determine if circulating levels of metabolic hormones 12 weeks following a GDM pregnancy are associated with an increased risk of type 2 diabetes 8-10 years later.

METHODS

Fasting plasma concentrations of glucose, insulin, C-peptide, ghrelin, GIP, GLP-1, glucagon, leptin, PAI-1, resistin and visfatin were measured in 98 normal glucose tolerant women, 12 weeks following an index GDM pregnancy. Women were assessed every 2 years for up to 10 years for development of overt type 2 diabetes.

RESULTS

After a median follow-up period of 8.7 years, 22.5% of women with a pGDM pregnancy developed type 2 diabetes. Significant risk factors for the development of type 2 diabetes were fasting plasma glucose levels >5 mmol/L during pregnancy and at 12 weeks post-pregnancy. In addition, higher C-peptide levels and lower ghrelin levels at 12 weeks post-pregnancy were also significant risk factors for the development of type 2 diabetes.

CONCLUSIONS

Fasting plasma glucose during pregnancy and post-partum, and post-partum C-peptide and ghrelin levels were significant risk factors for the development of type 2 diabetes in women with pGDM. This is the first report that identifies C-peptide and ghrelin as potential biomarkers for the prediction of type 2 diabetes in women with a history of GDM.

The association between the serum C-peptide level and bone mineral density

Objective

Although serum C-peptide was previously considered biologically inactive, a growing number of recent studies have shown that it is an active peptide with important physiologic functions. The present study aimed to investigate the association of serum C-peptide level with bone mineral density (BMD) in residents of the United States.

Methods

The study included 6,625 participants aged 12–85 years. Total and regional BMD were measured using dual-energy X-ray absorptiometry. Stratified multiple linear regression analysis was performed to determine the association of the serum C-peptide level with BMD. Three regression models were produced for each stratum. All models were adjusted for ethnicity, height, weight, education level, physical activity, smoking status, alcohol use, triglycerides and creatinine level, and models 2 and 3 were further adjusted for the fasting plasma glucose (FPG) and alkaline phosphatase (ALP) levels, respectively.

Results

Sex-specific results showed a significant association between the serum C-peptide level and total BMD in both sexes. Stratified analyses based on age and body mass index showed that serum C-peptide levels were significantly negatively associated with most regional BMD, and most of these associations remained significant after stratification based on the serum insulin level.

Conclusion

The serum C-peptide level was significantly negatively associated with the total and most regional BMD. These findings suggest that serum C-peptide may have biological activity associated with bone metabolism and therefore serum C-peptide control is advisable in order to reduce the risk of low bone mineral density.