Association between glycosylated hemoglobin and cancer risk: a New Zealand linkage study

Rapid and sensitive detection of cell surface N-glycans in live cancer cells using a novel acid-activated concanavalin A nanosensor

Glycans on the surface of cells play critical roles in various biological processes, including cell communication, the immune response, infection, development, and differentiation. The presence of glycans is closely related to cancer growth and metastasis. This study presents a biosensor based on an acid-activated nanoplatform for glycan detection on live cancer cells. Using human breast cancer cells (MCF-7 cells) and N-glycans as the target, concanavalin A (ConA)-modified magnetic nanoparticles (ConA-Cu(II)-MNPs) serve as the loading interface. Specifically, the nanoprobe consists of ConA with active N-glycan binding sites, glucose, and 5(6)-carboxytetramethylrhodamine (TAMRA) conjugated to pH-sensitive PDPA polymeric micelles, and these elements are used to prepare the acid-activated biosensor. In this strategy, the magnetic nanoparticle interface increases the loading capacity of ConA, and the active mannose binding sites allow ConA to capture the target cells. Therefore, the presence of glycans on the cell surface is reflected by the number of cells captured on the interface. Upon the addition of the specific nanoprobe to the captured cells at pH < 6.0, TAMRA is released from the micelles, generating a fluorescence signal. Additionally, the ConA on the nanoprobe specifically recognizes MCF-7 cells. The increase in the number of target cells captured on the ConA-Cu(II)-MNP interface leads to the loading of more TAMRA nanoprobes, and subsequently, a stronger fluorescence signal. The nanoprobe exhibits a substantial response to MCF-7 cells, detecting them at concentrations as low as 10 cells/mL. This biosensor can also selectively monitor changes in mannose levels on the cell surface after treatment with an N-glycan inhibitor. Using A549 and MRC-5 cells as models, the developed strategy demonstrates a low detection limit (down to three cells) and a wide linear detection range (from 10 to 1 × 106 cells/mL). Therefore, this acid-activated biosensor shows great potential for analyzing glycosylation on the surfaces of different cell types.

Association between metabolic disorders and clinicopathologic features in endometrial cancer

Background

In recent years, the incidence of Endometrial cancer (EC) has been on the rise due to high-fat, high-calorie diets and low-exercise lifestyles. However, the relationships between metabolic disorders and the progression of EC remain uncertain. The purpose of our study was to explore the potential association between obesity, hypertension, hyperglycemia and clinicopathologic characteristics in EC patients.

Methods

In categorical variables, Chi-square tests were used to calculate P values. Univariate logistic regression and multivariate logistic regression were used to identify the risk factors of myometrial invasion>1/2 and lymph node metastasis. Overall survival (OS) was estimated using the Kaplan-Meier method.

Results

The study included 406 individuals with EC, 62.6% had type I and 37.4% had type II. Hypertension was seen in 132 (32.5%), hyperglycemia in 75 (18.5%), and overweight or obesity in 217 (53.4%). Hypertension, hyperglycemia, and obesity are strongly associated with the clinicopathologic features of EC. Multivariate logistic regression revealed that hyperglycemia (OR=2.439,95% CI: 1.025-5.804, P = 0.044) was a risk factor for myometrial invasion depth >1/2 in patients with type I EC, and hypertension (OR=32.124,95% CI: 3.287-313.992, P = 0.003) was a risk factor for lymph node metastasis in patients with type I EC. Survival analysis found that hyperglycemia (P < 0.001) and hypertension (P = 0.002) were associated with OS in type I EC. Neither hyperglycemia, hypertension, nor obesity were associated with the prognosis in type II EC.

Conclusion

Hyperglycemia was a risk factor for myometrial invasion depth >1/2 in patients with type I EC and hypertension was a risk factor for lymph node metastasis in patients with type I EC. Hypertension and hyperglycemia were associated with poor prognosis in patients with type I EC.

A low-glucose eating pattern is associated with improvements in glycemic variability among women at risk for postmenopausal breast cancer: an exploratory analysis

Background

High glycemic variability (GV) is a biomarker of cancer risk, even in the absence of diabetes. The emerging concept of chrononutrition suggests that modifying meal timing can favorably impact metabolic risk factors linked to diet-related chronic disease, including breast cancer. Here, we examined the potential of eating when glucose levels are near personalized fasting thresholds (low-glucose eating, LGE), a novel form of timed-eating, to reduce GV in women without diabetes, who are at risk for postmenopausal breast cancer.

Methods

In this exploratory analysis of our 16-week weight loss randomized controlled trial, we included 17 non-Hispanic, white, postmenopausal women (average age = 60.7 ± 5.8 years, BMI = 34.5 ± 6.1 kg/m2, HbA1c = 5.7 ± 0.3%). Participants were those who, as part of the parent study, provided 3-7 days of blinded, continuous glucose monitoring data and image-assisted, timestamped food records at weeks 0 and 16. Pearson's correlation and multivariate regression were used to assess associations between LGE and GV, controlling for concurrent weight changes.

Results

Increases in LGE were associated with multiple unfavorable measures of GV including reductions in CGM glucose mean, CONGA, LI, J-Index, HBGI, ADDR, and time spent in a severe GV pattern (r = -0.81 to -0.49; ps < 0.044) and with increases in favorable measures of GV including M-value and LBGI (r = 0.59, 0.62; ps < 0.013). These associations remained significant after adjusting for weight changes.

Conclusion

Low-glucose eating is associated with improvements in glycemic variability, independent of concurrent weight reductions, suggesting it may be beneficial for GV-related disease prevention. Further research in a larger, more diverse sample with poor metabolic health is warranted.Clinical trial registration: ClinicalTrials.gov, NCT03546972.

Circulating levels of biomarkers and risk of ductal carcinoma in situ of the breast in the UK Biobank study

Observational studies have shown associations between circulating levels of various biomarkers (eg, total cholesterol [TC], low-density lipoprotein cholesterol [LDL], insulin-like growth factor-1 [IGF-1], C-reactive protein [CRP] and glycated hemoglobin-1c [HbA1c]) and the risk of invasive breast cancer (IBC). Ductal carcinoma in situ of the breast (DCIS) is a nonobligate precursor of IBC and shares several risk factors with it. However, the relationship between these biomarkers and DCIS risk remains unexplored. We studied the association between circulating levels of TC, LDL-C, high-density lipoprotein cholesterol (HDL-C), Lipoprotein (a) (Lp-(a)), IGF-1, CRP and HbA1c, with the risk of DCIS in 156801women aged 40 to 69 years and breast cancer-free at enrolment when blood samples and information on demographic and health-related factors were collected. Incident cases of DCIS were ascertained during the follow-up via linkage to the UK cancer registries Multivariable-adjusted Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of interest. In all, 969 DCIS incident cases were diagnosed during 11.4 years of follow-up. Total cholesterol was inversely associated with the risk of DCIS (HRquintile(Q)5vsQ1  = 0.47, 95% CI: 0.27-0.82, Ptrend  = .008). Conversely, LDL-C was positively associated with DCIS risk (HRQ3vsQ1  = 1.43, 95% CI: 1.01-2.04, HRQ4vsQ1  = 1.60, 95% CI: 1.04-2.47, HRQ5vsQ1  = 2.29, 95% CI: 1.36-3.88, Ptrend  = .004). In postmenopausal women, CRP had a weak positive association with DCIS risk, while HbA1c showed a nonlinear association with the risk. These results, in conjunction with those from previous studies on IBC, provide support for the association of several biomarkers with the risk of an early stage of breast cancer.

Association of Measures of Glucose Metabolism with Colorectal Cancer Risk in Older Chinese: A 13-Year Follow-up of the Guangzhou Biobank Cohort Study-Cardiovascular Disease Substudy and Meta-Analysis

BACKGRUOUND

Abnormal glucose metabolism is a risk factor for colorectal cancer (CRC). However, association of glycosylated hemoglobin (HbA1c) with CRC risk remains under-reported. We examined the association between glycemic indicators (HbA1c, fasting plasma glucose, fasting insulin, 2-hour glucose, 2-hour insulin, and homeostasis model of risk assessment-insulin resistance index) and CRC risk using prospective analysis and meta-analysis.

METHODS

Participants (n=1,915) from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Substudy were included. CRC events were identified through record linkage. Cox regression was used to assess the associations of glycemic indicators with CRC risk. A meta-analysis was performed to investigate the association between HbA1c and CRC risk.

RESULTS

During an average of 12.9 years follow-up (standard deviation, 2.8), 42 incident CRC cases occurred. After adjusting for potential confounders, the hazard ratio (95% confidence interval [CI]) of CRC for per % increment in HbA1c was 1.28 (95% CI, 1.01 to 1.63) in overall population, 1.51 (95% CI, 1.13 to 2.02) in women and 1.06 (95% CI, 0.68 to 1.68) in men. No significant association of other measures of glycemic indicators and baseline diabetes with CRC risk was found. Meta-analyses of 523,857 participants including our results showed that per % increment of HbA1c was associated with 13% higher risk of CRC, with the pooled risk ratio being 1.13 (95% CI, 1.01 to 1.27). Subgroupanalyses found stronger associations in women, colon cancer, Asians, and case-control studies.

CONCLUSION

Higher HbA1c was a significant predictor of CRC in the general population. Our findings shed light on the pathology of glucose metabolism and CRC, which warrants more in-depth investigation.

Diet quality and lung cancer incidence in a low-income population in the United States

BACKGROUND

Although tobacco smoking is the leading cause of lung cancer, interest in the relationship of diet quality on risk has been growing.

METHODS

We examined the association between Healthy Eating Index-2010 (HEI-10) at enrollment and lung cancer incidence among 70,802 participants in a predominantly African American and low-income prospective cohort in the southern United States. Outcomes were ascertained through linkages with state cancer registries and the National Death Index (NDI). Hazard ratios by HEI-10 quartiles were assessed using Cox proportional hazard models adjusted for potential confounders.

RESULTS

During ≤16 years of follow-up, 1454 incident lung cancers were identified. The lowest HEI-10 quartile compared to the highest was adversely associated with lung cancer risk (HR: 1.89, 95% CI 1.16-3.07) among male former smokers and female never smokers (HR: 2.58, 95% CI 1.06-6.28).

CONCLUSIONS

Low-quality diet was associated with increased lung cancer risk among male former smokers and female never smokers but cautious interpretation of the findings should be taken due to the small number of lung cancers among never smokers and the possibility of residual confounding by smoking in ever smokers.

Glucose metabolic reprogramming and its therapeutic potential in obesity-associated endometrial cancer

Endometrial cancer (EC) is a common gynecological cancer that endangers women health. Although substantial progresses of EC management have been achieved in recent years, the incidence of EC still remains high. Obesity has been a common phenomenon worldwide that increases the risk of EC. However, the mechanism associating obesity and EC has not been fully understood. Metabolic reprogramming as a remarkable characteristic of EC is currently emerging. As the primary factor of metabolic syndrome, obesity promotes insulin resistance, hyperinsulinemia and hyperglycaemia. This metabolic disorder remodels systemic status, which increases EC risk and is related with poor prognosis. Glucose metabolism in EC cells is complex and mediated by glycolysis and mitochondria to ensure energy requirement. Factors that affect glucose metabolism may have an impact on EC initiation and progression. In this study, we review the glucose metabolic reprogramming of EC not only systemic metabolism but also inherent tumor cell metabolism. In particular, the role of glucose metabolic regulation in malignant properties of EC will be focused. Understanding of metabolic profile and glucose metabolism-associated regulation mechanism in EC may provide novel perspective for treatment.

Is hemoglobin A1c valuable for predicting concurrent endometrial cancer in diabetic women with endometrial intraepithelial neoplasia?

AIM

The purpose of this study was to determine the predictive value of preoperative hemoglobin A1c (HgA1c) level for endometrial cancer in diabetic women with endometrial intraepithelial neoplasia (EIN).

MATERIALS AND METHODS

Six hundred patients with EIN were retrospectively studied in a tertiary referral center in Turkey between January 2014 and December 2021. One hundred and thirteen diabetic patients with EIN who met the inclusion criteria were enrolled in the study and divided into three groups according to the final pathological results: Group 1 with benign findings (n = 29), Group 2 with EIN (n = 34) and Group 3 with endometrial cancer (n = 50). Demographic, clinical and biochemical characteristics were compared among the three groups. Receiver operating characteristic analysis (ROC) was used to evaluate the predictive value of HgA1c for concurrent endometrial cancer in EIN.

RESULTS

Mean preoperative HgA1c levels were different among three groups (5.41 ± 0.64, 6.01 ± 0.72, 6.65 ± 1.15, p < 0.001, respectively). The highest value of HgA1c level was found in cancer group and difference within pairs was statistically significant (p < 0.001). Age and duration of menopause were also different among groups (p < 0.005). After adjustment of HgA1c level for age and duration of menopause differences were maintained (p < 0.001), the cutoff value was detected as ≥6.05% for HgA1c and sensitivity, specificity was 60%, 70%, respectively (p < 0.001).

CONCLUSIONS

HgA1c could be used in prediction of endometrial cancer. The optimal cutoff value determined in our study could be considered in predicting endometrial cancer in diabetic women with EIN.

Prospective associations of hemoglobin A1c and c-peptide with risk of diabetes-related cancers in the Cancer Prevention Study-II Nutrition Cohort

Self-reported type 2 diabetes mellitus (T2DM) is a risk factor for many cancers, suggesting its pathology relates to carcinogenesis. We conducted a case-cohort study to examine associations of hemoglobin A1c (HbA1c) and c-peptide with cancers associated with self-reported T2DM. This study was drawn from a prospective cohort of 32,383 women and men who provided blood specimens at baseline: c-peptide and HbA1c were assessed in 3,000 randomly selected participants who were cancer-free-at-baseline and an additional 2,281 participants who were cancer-free-at-baseline and subsequently diagnosed with incident colorectal, liver, pancreatic, female breast, endometrial, ovarian, bladder, or kidney cancers. Weighted-Cox regression models estimated hazards ratios (HRs) and 95% confidence intervals (CI), adjusted for covariates. C-peptide was associated with higher risk of liver cancer (per standard deviation (SD) HR: 1.80; 95%CI: 1.32-2.46). HbA1c was associated with higher risk of pancreatic cancer (per SD HR: 1.21 95%CI 1.05-1.40) and with some suggestion of higher risks for all-cancers-of-interest (per SD HR: 1.05; 95%CI: 0.99-1.11) and colorectal (per SD HR: 1.09; 95%CI: 0.98-1.20), ovarian (per SD HR: 1.18; 95%CI 0.96-1.45) and bladder (per SD HR: 1.08; 95%CI 0.96-1.21) cancers. Compared to no self-reported T2DM and HbA1c <6.5% (reference group), self-reported T2DM and HbA1c <6.5% (i.e., T2DM in good glycemic control) was not associated with risk of colorectal cancer, whereas it was associated with higher risks of all-cancers-of-interest combined (HR: 1.28; 95%CI: 1.01-1.62), especially for breast and endometrial cancers. Additional large, prospective studies are needed to further explore the roles of hyperglycemia, hyperinsulinemia, and related metabolic traits with T2DM-associated cancers to better understand the mechanisms underlying the self-reported T2DM-cancer association and to identify persons at higher cancer risk.

Frequency and association of self-reported oral cancer among individuals with type 2 diabetes at a tertiary care diabetes centre in South India - A retrospective study

AIM

To assess the frequency of self-reported oral cancer and associated factors among individuals with type 2 diabetes (T2D) at a tertiary care diabetes centre in South India.

METHODS

Individuals with T2D who reported that they had oral cancer were included from the Diabetes Electronic Medical Records (DEMR) database. To assess the association of oral cancer with T2D, a retrospective nested case-control study design was adopted. Individuals with T2D and oral cancer diagnosed after the diagnosis of T2D (n = 78) were considered 'cases', while T2D without oral cancer were considered 'controls' (312) [in a ratio of 1:4 for cases and controls]. The cases and controls were matched for age, gender and duration of diabetes. Logistic regression was used to model predictors of oral cancer in T2D patients.

RESULTS

Oral cancer was reported in 78 out of 379,138 (0.02%) individuals with T2D registered at the centre. Logistic regression analysis showed that a HbA1c value ≥ 9% had a significant association with oral cancer with an odds ratio of 2.3 (95% CI: 1.2-4.6) after adjusting for confounding factors. Among individuals with T2D, higher frequency of oral cancer prevalence and risk was observed among those who used any form of tobacco (32.6%, OR = 2.52, 95% CI: 1.5-4.3), consumed alcohol (29.2%, OR = 2.01, 95% CI: 1.2-3.3), and those with hypertension (23.9%, OR = 2.05, 95% CI: 1.2-3.6) and hypertriglyceridemia (24.7%, OR = 1.66, 95% CI: 1.01-2.7). Significant independent predictors of oral cancer among T2D were tobacco use (OR = 2.06, 95% CI: 1.1-4.00), high HbA1c (OR = 1.3, 95% CI: 1.03-1.5), hypertension (OR = 2.3, 95% CI: 1.3-4.2) and insulin use (OR = 1.8, 95% CI: 1.03-3.2).

CONCLUSIONS

Regular dental check-ups as part of the follow-up for individuals with T2D will identify and diagnose oral cancer earlier. Further research is required to assess the physiological and biological mechanisms leading to oral cancer in individuals with T2D.

Biomarkers of glucose homeostasis and inflammation with risk of prostate cancer: A case-cohort study

BACKGROUND

Few prospective studies have examined biomarkers of glucose homeostasis or inflammation with prostate cancer risk by tumor stage or grade.

METHODS

We conducted a case-cohort study to examine associations of pre-diagnosis hemoglobin A1c (HbA1c), c-peptide, and c-reactive protein (CRP) with prostate cancer risk overall and stratified by tumor stage and grade. The study included 390 non-aggressive (T1-2, N0, M0 and Gleason score <8) and 313 aggressive cases (T3-4, or N1, or M1, or Gleason score 8-10) diagnosed after blood draw (1998-2001) and up to 2013, and a random sub-cohort of 1,303 cancer-free men at blood draw in the Cancer Prevention Study-II Nutrition Cohort. Prentice-weighted Cox proportional hazards regression models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

In the multivariable-adjusted model without body mass index (BMI), HbA1c was inversely associated with non-aggressive prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00, P=0.04). Analyses stratified by tumor stage and grade separately showed that HbA1c was inversely associated with low-grade prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00) and positively associated with high-grade prostate cancer (HR per unit increase: 1.15, 95% CI: 1.01-1.30). C-peptide and CRP were not associated with prostate cancer overall or by stage or grade.

CONCLUSIONS

The present study suggests that associations of hyperglycemia with prostate cancer may differ by tumor grade and stage.

IMPACT

Future studies need to examine prostate cancer by tumor stage and grade, and to better understand the role of hyperglycemia in prostate cancer progression.

Haemoglobin A1c and serum glucose levels and risk of gastric cancer: a systematic review and meta-analysis

Background

This systematic review and meta-analysis examined associations between serum levels of haemoglobin A1c (HbA1c) and glucose and the risk of gastric cancer.

Methods

MEDLINE, Embase, and Cochrane Library were searched for studies examining associations between serum levels of HbA1c or glucose and the risk of gastric cancer. Inclusion of studies, quality assessment, and data extraction were conducted independently by two authors. Pooled hazard ratios (HR) with 95% confidence intervals (CI) were synthesised using random-effects models. Cochran’s Q test and I² statistic were used to assess heterogeneity.

Results

Among 3473 identified studies, 12 were included. Of these, 5 studies examined HbA1c levels and 7 studies examined serum glucose levels. Serum HbA1c levels >6% were associated with an increased risk of gastric cancer (HR 1.36, 95% CI 1.06–1.74). When compared with the lowest glucose categories, the highest glucose categories were associated with a borderline increased risk of gastric cancer (HR 1.11, 95% CI 0.98–1.26). In subgroup analyses, studies that adjusted for Helicobacter pylori infection indicated stronger associations between elevated HbA1c levels and gastric cancer (HR 2.08, 95% CI 1.46–2.98) than those without such adjustment (HR 1.10, 95% CI 0.91–1.32).

Conclusions

Long-standing poor glycaemic control may increase the risk of gastric cancer.

Registration number

PROSPERO CRD42020157453.

Association between time in range and cancer mortality among patients with type 2 diabetes: a prospective cohort study

Background:

Little was known about the association among time in range (TIR), time above range (TAR), time below range (TBR), and cancer mortality among patients with type 2 diabetes. We aimed to investigate the association among TIR, TAR, TBR, and the risk of cancer mortality among patients with type 2 diabetes.

Methods:

A total of 6225 patients with type 2 diabetes were prospectively recruited in Shanghai, China. TIR was measured with continuous glucose monitoring at baseline and was defined as the average percentage of time in the target glucose range during a 24 h period. Cox proportion hazard regression analysis was used to determine the association between TIR and the risk of cancer mortality.

Results:

During a mean follow-up of 7.10 years, we confirmed 237 death events related to cancer. The multivariable-adjusted hazard ratio (HR) for cancer mortality was 1.32 (95% confidence interval [CI]: 1.01–1.75) in patients with TIR ≤70% compared with those with TIR >70%. When TIR was considered as a continuous variable, the multivariable-adjusted HR for cancer mortality associated with each 10% decrease in TIR was 1.07 (95% CI: 1.02–1.14). In the site-specific analysis, a significant association between TIR as a continuous variable and the risk of hepatocellular cancer was found (HR: 1.24; 95% CI: 1.09–1.41). However, no relationship between hemoglobin A1c and cancer mortality was observed (HR: 1.04; 95% CI: 0.97–1.10).

Conclusions:

The present study found an inverse association of TIR with the risk of cancer mortality among patients with type 2 diabetes. New evidence of TIR was added into the clinical practice that TIR may be an optimal target of glycemic control among patients with type 2 diabetes.

High-sensitivity C-reactive protein, hemoglobin A1c and breast cancer risk: a nested case-control study from Alberta's Tomorrow Project cohort

PURPOSE

Our aim is to examine the associations between high-sensitivity C-reactive protein (hsCRP) and hemoglobin A1c (HbA1c), common biomarkers of inflammation and insulin resistance, respectively, with breast cancer risk, while adjusting for measures of excess body size.

METHODS

We conducted a nested case-control study within the Alberta's Tomorrow Project cohort (Alberta, Canada) including 197 incident breast cancer cases and 394 matched controls. The sample population included both pre- and postmenopausal women. Serum concentrations of hsCRP and HbA1c were measured from blood samples collected at baseline, along with anthropometric measurements, general health and lifestyle data. Conditional logistic regression was used to evaluate associations between hsCRP, HbA1c, and breast cancer risk adjusted for excess body size (body fat percentage) and other risk factors for breast cancer.

RESULTS

Higher concentrations of hsCRP were associated with elevated breast cancer risk (odds ratio [OR] 1.27; 95% confidence interval [95% CI] 1.03-1.55). The observed associations were unchanged with adjustment for body fat percentage. Higher HbA1c concentrations were not significantly associated with an increased breast cancer risk (OR 1.22; 95% CI 0.17-8.75).

CONCLUSION

These data suggest that hsCRP may be associated with elevated breast cancer risk, independent of excess body size. However, elevated concentrations of HbA1c did not appear to increase breast cancer risk in apparently healthy women.

Risk of 16 cancers across the full glycemic spectrum: a population-based cohort study using the UK Biobank

INTRODUCTION

Diabetes is observed to increase cancer risk, leading to hypothesized direct effects of either hyperglycemia or medication. We investigated associations between glycosylated hemoglobin (HbA1c) across the whole glycemic spectrum and incidence of 16 cancers in a population sample with comprehensive adjustment for risk factors and medication.

RESEARCH DESIGN AND METHODS

Linked data from the UK Biobank and UK cancer registry for all individuals with baseline HbA1c and no history of cancer at enrollment were used. Incident cancer was based on International Classification of Diseases - 10th Edition diagnostic codes. Age-standardized incidence rates were estimated by HbA1c category. Associations between HbA1c, modeled as a restricted cubic spline, and cancer risk were estimated using Cox proportional hazards models.

RESULTS

Among 378 253 individuals with average follow-up of 7.1 years, 21 172 incident cancers occurred. While incidence for many of the 16 cancers was associated with hyperglycemia in crude analyses, these associations disappeared after multivariable adjustment, except for pancreatic cancer (HR 1.55, 95% CI 1.22 to 1.98 for 55 vs 35 mmol/mol), and a novel finding of an inverse association between HbA1c and premenopausal breast cancer (HR 1.27, 95% CI 1.00 to 1.60 for 25 vs 35 mmol/mol; HR 0.71, 95% CI 0.54 to 0.94 for 45 vs 35 mmol/mol), not observed for postmenopausal breast cancer. Adjustment for diabetes medications had no appreciable impact on HRs for cancer.

CONCLUSIONS

Apart from pancreatic cancer, we did not demonstrate any independent positive association between HbA1c and cancer risk. These findings suggest that the potential for a cancer-inducing, direct effect of hyperglycemia may be misplaced.

The Role of Hyperglycemia in Endometrial Cancer Pathogenesis

Endometrial cancer is one of the most common cancers in women worldwide and its incidence is increasing. Epidemiological evidence shows a strong association between endometrial cancer and obesity, and multiple mechanisms linking obesity and cancer progression have been described. However, it remains unclear which factors are the main drivers of endometrial cancer development. Hyperglycemia and type 2 diabetes mellitus are common co-morbidities of obesity, and there is evidence that hyperglycemia is a risk factor for endometrial cancer independent of obesity. This review aims to explore the association between hyperglycemia and endometrial cancer, and discuss the evidence supporting a role for increased glucose metabolism in endometrial cancer and how this phenotype may contribute to endometrial cancer growth and progression. Finally, the potential role of blood glucose lowering strategies, including drugs and bariatric surgery, for the treatment of this malignancy will be discussed.

Diabetes, Glycated Hemoglobin, and Risk of Cancer in the UK Biobank Study

BACKGROUND

Evidence suggest that diabetes and glycated hemoglobin (HbA1c) levels are associated with cancer risk. However, previous studies have been limited variably by failure to adjust for cancer-specific risk factors (e.g., body mass index), inattention to diabetes duration and use of antidiabetic medications, and failure to stratify by obesity.

METHODS

We examined the association between diabetes, HbA1c, and cancer risk in the UK Biobank, using data from 476,517 participants (54% women), followed for an average period of 7.1 years. Diabetes was defined on the basis of baseline self-reported diagnosis of diabetes and/or use of diabetes medication, while HbA1c measured at baseline was categorized as low (<31 mmol/mol), normal (31-<39 mmol/mol), increased risk (39-<48 mmol/mol), and high risk for diabetes (≥48 mmol/mol). Multivariable Cox proportional hazards models were used to estimate the association of diabetes and cancer at different anatomical sites, with adjustment for cancer-specific risk factors.

RESULTS

Diabetes was associated with increased risk of cancers of the stomach, liver, bladder, endometrium, and lung among smokers, and with decreased risk of prostate cancer. Compared with the normal HbA1c category, the increased risk category was positively associated with risk of cancers of the colon, liver, bladder, and lung among smokers, and the high-risk category was associated with increased risk of cancers of the esophagus, liver, pancreas, and bladder, and with decreased risk of prostate cancer.

CONCLUSIONS

These results suggest that both diabetes and/or elevated HbA1c are associated with risk of cancer at several anatomic sites.

IMPACT

The associations of diabetes and HbA1c levels with cancer suggest their importance in cancer prevention.

Development of malignancies and changes in time-dependent hemoglobin A1c among a nondiabetic population: longitudinal analysis

BACKGROUND

The fluctuation of hemoglobin A1c (HbA1c) and changes in health habits over time was not considered in previous studies. The aim of this study was to evaluate the time-sequenced association between malignancy incidence and HbA1c with a longitudinal study design using repeated measurements of HbA1c.

METHODS

A retrospective longitudinal study was conducted at a large teaching hospital in Tokyo, Japan, from 2005 to 2016. All participants who underwent voluntary health check-ups at the hospital were included. Our outcomes were the development of malignancy. We compared these outcomes using HbA1c categories. Longitudinal analyses were conducted with a mixed effects model in which time-dependent HbA1c measurements were applied to consider fluctuations in HbA1c levels, adjusted for covariates.

RESULTS

A total of 77,385 nondiabetic participants were included in the study; the mean age was 44.7 and 49.4% of participants were male. During a median follow-up of 1588 (interquartile range 730-2946) days, 4506 (5.8%) participants developed malignancies. The relationship between future malignancies and HbA1c was U-shaped; both the lower HbA1c groups (OR 1.31, 95% CI 1.17-1.46 for < 5.0%) and the higher HbA1c group (OR 1.87, 95% CI 1.03-3.39 for ≥ 7.5%) had significantly higher odds ratios compared to the 5.5-5.9%. The lowest HbA1c was associated with higher odds of breast cancer (OR 1.5, 95% CI 1.21-1.86) and female genital cancer (OR 1.57, 95% CI 1.04-2.37).

CONCLUSIONS

Our study found a U-shaped association between HbA1c and future malignancies among nondiabetic people but did not find additional risk at the prediabetic level. Low HbA1c may be associated with the incidence of breast cancer and female genital cancer.

Glycemic variability and subsequent malignancies among the population without diabetes

BACKGROUND

Glycemic variability has been suggested to be related to some unfavorable outcomes, but malignancy development has not been evaluated. The aim of this study was to evaluate the association of glycemic variability with malignancy development among the population without diabetes.

METHODS

We conducted a retrospective cohort study at a large teaching hospital in Tokyo, Japan, from 2005 to 2016. We included all participants without diabetes who underwent voluntary health check-ups. Our outcome was the development of any malignancy. As a measure of glycemic variability, we calculated the quotient of CV in HbA1c and categorized subjects into quartile groups. A Cox proportional hazard model was applied, adjusting for patient demographics and social and family histories.

RESULTS

A total of 42,731 participants were included in this study; the mean age was 53.8 and 48.3% were male. During the median follow up of 2639 (interquartile range (IQR):1787-3662) days, 2435 participants (5.7%) developed malignancies. Participants who had larger glycemic variability (CV in HbA1c; hazard ratio (HR) 1.15, 95%confidence interval (CI):1.02-0.31 for the second quartile group; HR 2.20, 95%CI:1.95-2.48 for the third quartile group, HR 4.66, 95%CI:4.16-5.21 for the fourth quartile group, compared to first quartile group) had a significantly higher risk of malignancies.

CONCLUSION

We found an association between large glycemic variability and a high risk of future malignancies in a dose-dependent manner among people without diabetes. This finding suggests that maintaining a constant level of glucose may have favorable effects on cancer prevention in people without diabetes.

Plasma C-peptide and glycated albumin and subsequent risk of cancer: From a large prospective case-cohort study in Japan

To elucidate the individual impacts of insulin and blood glucose on cancer risk, we investigated the association of plasma C-peptide, a surrogated marker of insulin and glycated albumin (GA), a more stable marker of blood glucose, with all-site and site-specific cancer risk by mutually accounting for their confounding effects. The study was prospectively conducted with nearly 4,000 cancer cases arising in our population-based cohort of 33,736 subjects who answered the baseline questionnaire and supplied blood samples. After exclusion of subjects with apparent DM, analysis was done in 3,036 cancer cases and 3,667 subcohort subjects. Among men and women combined, highest levels of C-peptide were statistically significantly associated with an increased risk of all-site [Hazard ratio (HR): 1.21; 95% confidence interval: 1.02-1.42], colon [1.73; 1.20-2.47], liver [3.23; 1.76-5.91], kidney, renal pelvis and ureter cancers [2.47; 1.07-5.69], compared to the respective lowest levels, after adjustment for GA levels. Among these C-peptide-related cancers, colon and liver cancers also showed an increased risk associated with elevated GA levels independently of C-peptide levels. The corresponding HRs for colon and liver cancers compared to the highest and lowest GA levels were 1.43 [1.02-2.00] and 2.02 [1.15-3.55], respectively. Effect modification by gender was only evident for the association between C-peptide and colon cancer (p for interaction = 0.04). Higher insulin levels, independently of higher blood glucose levels, may be relevant to DM-related carcinogenesis for several cancer sites. Examination of circulating insulin levels is a plausible option in evaluating cancer risk even in individuals who have not developed DM.

Association between postprandial hyperglycemia at clinic visits and all-cause and cancer mortality in patients with type 2 diabetes: A long-term historical cohort study in Japan

AIMS

To evaluate the effect of postprandial hyperglycemia at clinic visits on all-cause and cancer mortality independent of glycated hemoglobin (HbA1c) levels in a real-world setting in Japanese patients with type 2 diabetes. We also investigated age at death.

METHODS

This historical cohort study included 1582 patients with type 2 diabetes who first visited our clinic from 1995 to 1998 and continued visiting for at least 1 year. The patients were followed up through 2017. Blood glucose levels at 2 h ± 30 min post-breakfast (2h-PBBG) were measured in 926 patients during the first year. The first measurements of 2h-PBBG levels were used as a measure of postprandial hyperglycemia.

RESULTS

A total of 233 patients died. The average age at death (men/women) was 75.6/80.8 years. A total of 139 patients who had 2h-PBBG levels measured died, including 46 deaths from cancer. Multivariate Cox regression analysis showed that 2h-PBBG levels significantly predicted all-cause and cancer mortality independent of HbA1c levels.

CONCLUSIONS

Postprandial hyperglycemia at clinic visits may be associated with all-cause and cancer mortality in patients with type 2 diabetes independent of HbA1c levels. As this is a small observational study, further studies are warranted to confirm our findings.

Distinct Metabolic Profiles are Associated with Colorectal Adenomas and Serrated Polyps

OBJECTIVE

Prevention of colorectal cancer (CRC) by colonoscopy is recommended according to age and personal/familial history. Metabolic alterations are associated with colorectal adenomas, but data are scarce regarding serrated polyps and advanced polyps. The aim of this study was to evaluate the association between metabolic alterations and colorectal polyp type and advanced polyps.

METHODS

A case-control study was conducted among consecutive subjects, 40 to 70 years old, who underwent screening/diagnostic colonoscopy from 2010 to 2015. Subjects who were treated for diabetes, who had a family/personal history of CRC, and who were at high risk for CRC were excluded. Participants underwent anthropometric, laboratory, and ultrasonographic evaluations and a medical and lifestyle interview. Polyps were histologically classified as adenomatous or serrated polyps and divided into advanced and non-advanced categories.

RESULTS

The study included 828 participants (58.4 ± 6.6 years, 50.4% men). Abdominal obesity (odds ratio [OR] = 1.67, 95% CI: 1.20-2.30), hypertension (OR = 1.47, 95% CI: 1.03-2.09), and a high glycosylated hemoglobin percentage (HbA1c%) (OR = 1.57, 95% CI: 1.06-2.34) were independently associated with colorectal adenomas, whereas a high triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio was independently associated with serrated polyps (OR = 2.31, 95% CI: 1.32-4.03). A combination of three metabolic alterations was strongly associated with colorectal polyps.

CONCLUSIONS

Abdominal obesity, hypertension, and a high HbA1c% are independently associated with adenomas, whereas a high TG/HDL ratio is associated with serrated polyps. These parameters are easily accessible in clinical practice and may help define high-risk groups for CRC.

Enemies or weapons in hands: investigational anti-diabetic drug glibenclamide and cancer risk

Epidemiological evidence suggests that diabetes is associated with elevated cancer risk through the actions of hyperglycemia, hyperinsulinemia and chronic inflammation. Metformin, a first-line medication for type 2 diabetes mellitus, arouses growing concerns on its anti-cancer effect. However, data regarding the effect of glibenclamide on tumor growth and cancer risk are less consistent, which may be a potential anti-cancer drug. Areas covered: In this review, we clarified probable underlying mechanisms in preclinical studies and reviewed epidemiological evidence on glibenclamide's cancer risk in clinical studies. Glibenclamide inhibited carcinogenesis through ATP-binding cassette protein super-family and ATP-sensitive potassium channels, while majority of clinical researches reported an increased or non-significant elevated cancer risk of glibenclamide users compared with metformin users. Other sulfonylureas and diarylsulfonylureas were also briefly introduced. Expert opinion: The inconsistency between the results of studies was probably ascribed to undiscovered mechanisms, confounding factors, inconsistent comparators and publication bias. Existing clinical trials were prone to be afflicted by time-related bias including immortal time bias, time-window bias, and time-lag bias. Glibenclimiade could be a promising and well-tolerated anti-neoplastic drug targeting ATP-binding cassette protein super-family and KATP channels, but its efficacy still needs to be proven in well-designed long-term randomized controlled clinical trials.

Risk factors for cancer development in type 2 diabetes: A retrospective case-control study

BACKGROUND

The risk of several types of cancer is increased in type 2 diabetes mellitus. The earliest possible diagnosis of cancer - difficult within regular outpatient diabetes care - is of utmost importance for patients' survival. The aim of this multicenter, retrospective (years 1998-2015), case-control study was to identify risk factors associated with malignancy in subjects with diabetes treated in a typical outpatient setting.

METHODS

In the databases of 3 diabetic and 1 primary care clinics 203 patients (115 women) with type 2 diabetes mellitus who developed malignancy while treated for diabetes were identified. The control group consisted of 203 strictly age- and gender matched subjects with type 2 diabetes without cancer. Factors associated with diabetes: disease duration, antidiabetic medications use and metabolic control of diabetes were analyzed. Also other variables: BMI (body mass index), smoking habits, place of residence and comorbidities were included into analysis.

RESULTS

The most prevalent malignancies in men and women together were breast cancer (20.7 %) and colorectal cancer (16.3 %). HbA1c (hemoglobin A1c) level ≥8.5 %, obesity and insulin treatment in dose-dependent and time-varying manner demonstrated significant association with increased risk of malignancy, while metformin use was associated with a lower risk of cancer. Diabetes duration, comorbidities, smoking habits, place of residence and aspirin use did not show significant association with risk of malignancy.

CONCLUSIONS

In the outpatient setting the obese patients with poorly controlled insulin treated type 2 diabetes mellitus should be rigorously assessed towards malignancies, particularly breast cancer in women and colorectal cancer in men.

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.

High hemoglobin A1c levels within the non-diabetic range are associated with the risk of all cancers

Previous studies have reported associations between diabetes and cancer risk. However, specific association of hemoglobin A1c (HbA1c) levels with cancer risk remains inconclusive. We followed 29,629 individuals (11,336 men; 18,293 women) aged 46-80 years who participated in the Japan Public Health Center-based prospective study who had HbA1c measurements available and were cancer-free at baseline. Cancer incidence was assessed by systemic surveys. We estimated hazard ratios (HRs) for cancer risk with adjustment for age sex, geographic area, body mass index, smoking status, physical activity, alcohol, coffee, vegetable and total energy consumption, and history of cardiovascular disease. After a median follow-up of 8.5 years, 1,955 individuals had developed cancer. Higher HbA1c levels within both the non-diabetic and diabetic ranges in individuals without known diabetes were associated with overall cancer risk. Compared with individuals without known diabetes and HbA1c levels of 5.0-5.4%, the HRs for all cancers were 1.27 (95% confidence interval, 1.07-1.52); 1.01 (0.90-1.14); 1.28 (1.09-1.49); and 1.43 (1.14-1.80) for individuals without known diabetes and HbA1c levels <5.0%, 5.5-5.9%, 6.0-6.4%, and ≥6.5%, respectively, and 1.23 (1.02-1.47) for individuals with known diabetes. The lowest HbA1c group had the highest risk of liver cancer, and HbA1c levels were linearly associated with the risk of all cancers after excluding liver cancer (P for linear trend, 0.004). In conclusion, our findings corroborate the notion that glycemic control in individuals with high HbA1c levels may be important not only to prevent diabetes but also to prevent cancer.

Evaluation of hemoglobin A1c levels in endometrial cancer patients: a retrospective study in Turkey

BACKGROUND

Hemoglobin A1c(HgA1c) is a marker of poor gylcemic control and elevation HgA1c is associated with increased risk of many cancers. We aimed to determine the HgA1c levels in endometrial cancer cases and any relationship with stage and grade of disease.

MATERIALS AND METHODS

A retrospective data review was performed between June 2011 and October 2012 at a tertiary referral center in Turkey. The study included 35 surgically staged endometrial cancer patients and 40 healthy controls. Preoperative HgA1c levels drawn within 3 months before surgery were compared. Also the relationships between HgA1c levels and stage, grade and hystologic type of cancer cases were evaluated.

RESULTS

The mean HgA1c levels were statistically significantly higher at 6.19 ± 1.44 in endometrial cancer cases than the 5.61 ± 0.58 in controls (p=0.027). With endometrial cancer cases, the mean HgA1c level was found to be 6.62 ± 1.40 for stage I and 6.88 ± 1.15 for stages II-IV (p=0.07). The figures were 6.74 ± 1.65 for endometrioid and 6.63 ± 1.41 for non-endometrioid type tumors (p=0.56). Mean HgA1c levels of 6.72 ± 1.14 for grade 1 and 6.62 ± 1.42 for grade 2-3 were observed (p=0.57).

CONCLUSIONS

HgA1c levels in endometrial cancer patients were statistically higher than healthy controls. However, HgA1c did not show any significant correlation with stage, grade and histologic type in endometrial cancer cases.

Is diabetes mellitus associated with increased incidence and disease-specific mortality in endometrial cancer? A systematic review and meta-analysis of cohort studies

OBJECTIVE

To assess the association between diabetes mellitus (DM) and the incidence and disease-specific mortality of endometrial cancer (EC).

METHODS

MEDLINE, EMBASE and conference abstracts of the 2011-2013 Annual Meetings of Society of Gynecological Oncology were searched for reports of original cohort studies that enrolled diabetic and non-diabetic women who were free of EC at baseline to compare the incidence and disease-specific mortality of EC by DM status. The included reports were examined for demographic characteristics of study populations, study design, effect measures and risk of bias. Statistical heterogeneity was evaluated with Chi-square test of the Cochrane Q statistics at the 0.05 significance level and I(2) statistic. Publication bias was assessed by visual examination of a funnel plot and the Egger's test for small-study effects.

RESULTS

Twenty-nine cohort studies (17 prospective, 12 retrospective) were eligible for this review, 23 of which reported EC incidence, five reported disease-specific mortality and one reported both. For incidence of EC among women with versus without DM, the summary relative risk (RR) was 1.89 (95%CI, 1.46-2.45; p<0.001) and the summary incidence rate ratio was 1.61 (95%CI, 1.51-1.71; p<0.001). The pooled RR of disease-specific mortality was 1.32 (95%CI, 1.10-1.60; p=0.003), while results in the studies reporting standardized mortality ratios were inconsistent. There remains considerable amount of clinical and methodological heterogeneity among the included studies; moreover, the hazard ratios for incident EC showed significant statistical heterogeneity and therefore were not quantitatively synthesized.

CONCLUSIONS

There is consistent evidence for an independent association between DM and an increased risk of incident EC, while the association between DM and EC-specific mortality remains uncertain. Further studies with better considerations for selection bias, information bias and confounding will further facilitate causal inference involving DM and EC.

Does cancer risk increase with HbA1c, independent of diabetes?

Background:

The risks for several cancer types are increased in people with diabetes. Hyperglycaemia, hyperinsulinaemia, inflammation and altered hormonal concentrations are common characteristics between the two diseases and can all be linked to hyperglycaemia.

Methods:

Here, we use glycated haemoglobin (HbA_1c) as a biomarker for chronic hyperglycaemia. We explore whether cancer risk increases with HbA_1c, independent of diabetes, and, therefore, if risk is already increased below the diabetic HbA_1c range, by analysing data from current studies linking HbA_1c to risk of several cancer types.

Results:

The data reveal that chronic hyperglycaemia correlates with increased cancer risk for a number of cancers, except prostate cancer. Evidence is also provided that risk is already increased in the pre-diabetic and normal ranges for several cancers.

Conclusions:

These results merit urgent investigation into the risks and advantages of updating recommendations for stricter glycaemic control in diabetic and non-diabetic subjects, as this could help reduce the risk of cancer incidence and mortality.

Stage-specific analysis of plasma protein profiles in ovarian cancer: Difference in-gel electrophoresis analysis of pooled clinical samples

INTRODUCTION

Ovarian cancer is the leading cause of death from gynecological cancer. Non-specific symptoms early in disease and the lack of specific biomarkers hinder early diagnosis. Multi-marker blood screening tests have shown promise for improving identification of early stage disease; however, available tests lack sensitivity, and specificity.

MATERIALS AND METHODS

In this study, pooled deeply-depleted plasma from women with Stage 1, 2 or 3 ovarian cancer and healthy controls were used to compare the 2-dimensional gel electrophoresis (2-DE) protein profiles and identify potential novel markers of ovarian cancer progression.

RESULTS/DISCUSSION

Stage-specific variation in biomarker expression was observed. For example, apolipoprotein A1 expression is relatively low in control and Stage 1, but shows a substantial increase in Stage 2 and 3, thus, potential of utility for disease confirmation rather than early detection. A better marker for early stage disease was tropomyosin 4 (TPM4). The expression of TPM4 increased by 2-fold in Stage 2 before returning to "normal" levels in Stage 3 disease. Multiple isoforms were also identified for some proteins and in some cases, displayed stage-specific expression. An interesting example was fibrinogen alpha, for which 8 isoforms were identified. Four displayed a moderate increase at Stage 1 and a substantial increase for Stages 2 and 3 while the other 4 showed only moderate increases.

CONCLUSION

Herein is provided an improved summary of blood protein profiles for women with ovarian cancer stratified by stage.

Diabetes and risk of cancer

Diabetes and cancer represent two complex, diverse, chronic, and potentially fatal diseases. Cancer is the second leading cause of death, while diabetes is the seventh leading cause of death with the latter still likely underreported. There is a growing body of evidence published in recent years that suggest substantial increase in cancer incidence in diabetic patients. The worldwide prevalence of diabetes was estimated to rise from 171 million in 2000 to 366 million in 2030. About 26.9% of all people over 65 have diabetes and 60% have cancer. Overall, 8–18% of cancer patients have diabetes. In the context of epidemiology, the burden of both diseases, small association between diabetes and cancer will be clinically relevant and should translate into significant consequences for future health care solutions. This paper summarizes most of the epidemiological association studies between diabetes and cancer including studies relating to the general all-site increase of malignancies in diabetes and elevated organ-specific cancer rate in diabetes as comorbidity. Additionally, we have discussed the possible pathophysiological mechanisms that likely may be involved in promoting carcinogenesis in diabetes and the potential of different antidiabetic therapies to influence cancer incidence.

Hemoglobin A1c and the relationship to stage and grade of endometrial cancer

OBJECTIVES

To determine if elevated markers of poor glycemic control (HgA1c and fasting glucose levels) in patients surgically staged for type I endometrial cancer is related to a higher stage or higher grade at the time of diagnosis. Also, to assess if these markers impact overall survival.

METHODS

A retrospective chart review was performed from January 2000 to June 2010 at three academic medical centers. Patients were included if they underwent surgical staging and had HgA1c drawn within 3 months before surgery. Demographic data, fasting blood glucose levels and overall survival data were also obtained.

RESULTS

Eighty-two patients fitting the inclusion criteria were identified during the study period. There was a strong positive correlation between HgA1c and fasting glucose. There was no statistical difference with regard to stage alone, grade alone, or when stratified together with regard to HgA1c or fasting glucose levels. There was a trend toward increased mean HgA1c across increasing stages, but this was not statistically significant. Diabetes, HgA1c and tumor grade did not affect overall survival, but advanced stage was a poor prognostic measure for overall survival.

CONCLUSIONS

Elevated preoperative HgA1c has a trend toward a higher stage at the time of diagnosis. Advanced stage is a poor prognostic measure for overall survival.

Glycated hemoglobin and cancer incidence and mortality in the Atherosclerosis in Communities (ARIC) Study, 1990-2006

Diabetes is a risk factor for many cancers; chronic hyperglycemia is hypothesized to be, in part, explanatory. We evaluated the association between glycated hemoglobin, a time-integrated glycemia measure, and cancer incidence and mortality in nondiabetic and diabetic men and women. We conducted a prospective study of 12,792 cancer-free participants attending the second visit (1990-1992) of the Atherosclerosis Risk in Communities (ARIC) Study. We measured glycated hemoglobin in whole-blood samples using HPLC. Incident cancers were ascertained from registries and hospital records through 2006. We estimated multivariable-adjusted hazard ratios (HR) of cancer incidence and mortality for nondiabetic participants with values ≥ 5.7% (elevated), nondiabetic participants with <5.0% (low) and diabetic participants all compared with nondiabetic participants with 5.0-5.6% (normal). We ascertained 2,349 incident cancer cases and 887 cancer deaths. Compared with nondiabetic women with normal glycated hemoglobin, nondiabetic women with elevated values had an increased risk of cancer incidence (HR:1.24; 95% CI:1.07,1.44) and mortality (HR:1.58; 95% CI:1.23,2.05) as did diabetic women (incidence, HR:1.30; 95% CI:1.06,1.60, mortality, HR:1.96; 95% CI:1.40,2.76). Nondiabetic women with low values also had increased risk. Diabetic women with good glycemic control (<7.0%) had a lower cancer risk than those with higher values. Glycated hemoglobin in nondiabetic and diabetic men, and diabetes were not statistically significantly associated with total cancer risk. Our findings support the hypothesis that chronic hyperglycemia, even in the nondiabetic range, increases cancer risk in women. Maintaining normal glycated hemoglobin overall, and good glycemic control among diabetic adults, may reduce the burden of cancer, especially in women.

No evidence of an increased mortality risk associated with low levels of glycated haemoglobin in a non-diabetic UK population

AIMS/HYPOTHESIS

There is debate about increased mortality risk associated with low levels of glycaemia. To address this issue, we examined the shape of the risk relationship between glycated haemoglobin and mortality in a UK population.

METHODS

In 17,196 men and women aged 39-82 years participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study in Norfolk without known diabetes or cardiovascular disease, we estimated HRs for total and cause-specific mortality comparing categories of glycated haemoglobin (<4.5%, 4.5% to <5.0%, 5.0% to <5.5% [reference], 5.5% to <6.0%, 6.0% to <6.5%, and ≥6.5%) using Cox regression.

RESULTS

During a mean (±SD) follow-up of 11.2 (±2.1) years 1,953 participants died. The HR for all-cause mortality increased with categories of increasing glycated haemoglobin in adjusted analyses (HR 0.94 [95% CI 0.72-1.22], 0.99 [0.86-1.13], 1.00 [0.92-1.08], 1.10 [1.02-1.19], 1.29 [1.14-1.46] and 1.45 [1.16-1.80]). Spline regression suggested no increased risk at the low end of the distribution. Indeed, the HR for all-cause mortality was virtually constant in the low range and only started to rise when the level was approximately 5.5%. There were similar associations of glycated haemoglobin with cause-specific mortality, with the strongest association being seen for cardiovascular mortality.

CONCLUSIONS/INTERPRETATION

Our findings in a large non-diabetic population do not support the concern about increased mortality risk with low glycated haemoglobin. Differences in population characteristics might explain contrary results of earlier studies and need further exploration.

Diabetes and cancer

Diabetes and cancer are common conditions, and their co-diagnosis in the same individual is not infrequent. A link between the two conditions has been postulated for almost 80 years, but only in the past decade has significant epidemiological evidence been amassed to suggest that diabetes and cancer are associated, and the link appears causal. Hyperinsulinaemia, adipocytokines, growth factors and epigenetic changes may be implicated in the pathogenesis of cancer amongst patients with diabetes, and recently, diabetes therapies have also been implicated. There is reasonable circumstantial evidence that metformin may decrease the risk of cancer amongst diabetic patients. Much more research is required to elucidate the link between diabetes and cancer, particularly the potential link with diabetes treatments.

A New Zealand linkage study examining the associations between A1C concentration and mortality

OBJECTIVE

To examine associations between A1C concentration and mortality in a New Zealand population.

RESEARCH DESIGN AND METHODS

During a Hepatitis Foundation screening campaign for hepatitis B (1999-2001), participants were offered A1C testing. The participants were anonymously linked to the national mortality collection to 31 December 2004. Hazard ratios (HRs) and 95% CIs adjusted for age, ethnicity, smoking, and sex were estimated using Cox regression.

RESULTS

There were 47,904 participants (71% Mâori, 12% Pacific, 5% Asian, and 12% other). A1C measurements were categorized as <4.0% (n = 142), 4.0 to <5.0% (reference category; n = 12,867), 5.0 to <6.0% (n = 30,222), 6.0 to <7.0% (n = 2,669), and >or=7.0% (n = 1,596); there were also 408 participants with a previous diabetes diagnosis. During the follow-up period, 815 individuals died. In those without a prior diabetes diagnosis, there were steadily increasing HRs from the A1C reference category to the highest category (>or=7.0%; HR 2.36 [95% CI 1.72-3.25]). As well as all-cause mortality, A1C was associated with mortality from diseases of the circulatory system; endocrine, nutritional, metabolic, and immunity disorders; and other and unknown causes. Mortality was also elevated in those with a prior diabetes diagnosis (5.19 [3.67-7.35]), but this was only partially explained by their elevated A1C levels.

CONCLUSIONS

This is the largest study to date of A1C levels and subsequent mortality risk. It confirms previous findings that A1C levels are strongly associated with subsequent mortality in both men and women without a prior diabetes diagnosis.