Colorectal cancer: another complication of diabetes mellitus?

Association of 25(OH)-Vitamin D and metabolic factors with colorectal polyps

BACKGROUND

Studies have revealed the association of vitamin D with specific types of cancer development, however, its correlation with colorectal polyps (CRPs) remains unverified. Our study aimed to investigate the relationship between vitamin D levels, metabolic factors, and CRPs.

METHODS

A cross-sectional study from 2017 to 2019 involving 1306 participants was conducted to investigate the association among vitamin D levels, metabolic factors, uric acid and CRPs in Taiwan. CRPs diagnoses were determined via colonoscopies conducted by experienced gastrointestinal physicians, and biopsied polyps were inspected under a microscope by experienced pathologists. We employed both simple and multiple logistic regression analyses to identify significant factors associated with CRPs and adenomatous polyps, respectively.

RESULTS

Our result showed that the prevalence of 25(OH)-vitamin D deficiency (≦ 20 ng/mL) and CRPs was 21.21% and 40.89%, respectively. Multiple logistic regression revealed that the risk of CRPs increased with old age, male sex, hyperglycemia, high triglyceride levels, and low 25(OH)D levels after adjustment for other factors. Besides, low 25(OH)D levels were significantly associated with CRPs risk in women, whereas elevated blood pressure was associated with CRPs risk in men. 25(OH)D Deficiency was revealed to be significantly associated with risk of CRPs in adults over 50 years old. Compared to nonadenomatous polyps, older age, higher 25(OH) vitamin D and higher uric acid levels were at increased risk for adenomatous polyps.

CONCLUSIONS

Our study revealed that vitamin D deficiency was significantly associated with the risk of CRPs, especially in adults over 50 years old and women. We should therefore be concerned about the CRP risk of vitamin D deficiency and metabolic syndrome (especially hyperglycemia, elevated blood pressure in men, and high triglyceride levels) in this population.

Fasting Blood Glucose Variability and Unfavorable Trajectory Patterns Are Associated with the Risk of Colorectal Cancer

Background/Aims

The relationship between fasting blood glucose (FBG) variability and colorectal cancer (CRC) remains ill-defined. This study aimed to evaluate the association of FBG variability with CRC risk in the healthy population without overt diabetes.

Methods

In the data from the Korean National Health Insurance Service-Health Screening Cohort, we included individuals examined by FBG testing at least 3 times between 2002 and 2007. FBG variability was calculated using standard deviation (SD) and coefficient of variation (CV).

Results

Regarding FBG variability, an increase in the quintile of SD or CV was independently associated with CRC risk (all p for trend <0.01). When the change in FBG was classified into six trajectory patterns, unfavorable trajectory patterns (high stable and upward) were significantly associated with increased CRC risk (hazard ratio [HR] 2.30, p=0.003; HR 1.19, p=0.007, respectively). In subgroup analyses according to the sex, a significant association between FBG variability (SD or CV) and CRC risk was observed in men but not in women. The high stable and upward pattern were also associated with CRC risk in men (HR 2.47, p=0.002; HR 1.21, p=0.012) but not in women.

Conclusions

This study identified that FBG variability and unfavorable trajectory patterns were significantly associated with increased CRC risk in the healthy population without overt diabetes. Our findings suggest that FBG variability as well as FBG itself may be a predictive factor for the development of CRC.

Narrative review of the influence of diabetes mellitus and hyperglycemia on colorectal cancer risk and oncological outcomes

Diabetes mellitus (DM) and hyperglycemia have been shown to have significant effects on the incidence, chemoresistance, and prognosis of colorectal cancer (CRC), as well as the outcomes of localized and metastatic CRC. Inflammation and endocrine effects may act as central mechanisms of DM and cancer and stimulate the insulin-like growth factor 1-phosphoinositide 3-kinase-Akt-mammalian target of rapamycin (IGF-1-PI3K-AKT-mTOR) pathway. Dysregulation of the AMP-activated protein kinase (AMPK) pathway leads to metabolic imbalance and indicates cancer risk. The use of metformin for chemoprevention has been shown to reduce CRC and adenoma incidence through the upregulation of AMPK, which causes cell cycle arrest in the Gap 1-S (G1-S) phase and inhibits the mTOR pathway, even potentially reversing the epithelial-mesenchymal transition. However, evidence of the effects of metformin remain controversial in cancer prognosis. Several genes, such as transcription factor 7-like 2(TCF7L2), tumor protein P53 inducible nuclear protein 1(TP53INP1), gremlin 1 (GREM1), and potassium voltage-gated channel subfamily Q member 1(KCNQ1), are pleiotropically related to DM as well as cancer risk and prognosis. Epigenetic modification of members of the Let-7 family such as miR-497, miR-486, and miR-223 is strongly associated with impaired glucose tolerance and CRC risk. Herein we review the pathophysiological and epidemiological evidence as well as potential underlying molecular mechanisms by which DM and hyperglycemia affect CRC risk. We also suggest potential roles of glucose modulation in CRC therapy and propose an agenda for future research and clinical practice.

Gender difference in metabolic syndrome and incident colorectal adenoma: A prospective observational study (KCIS No.42)

ABSTRACT

This community-based study aimed to elucidate whether there is a gender difference in the effect of metabolic syndrome (MetS) and its individual components on an elevated risk for incident colorectal adenoma.A prospective cohort study was conducted by enrolling 59,767 subjects aged 40 years or older between 2001 and 2009 in Keelung, Taiwan, to test this hypothesis, excluding those with a prior history of colorectal cancer and those with colorectal cancer diagnosed at the first screening. Cox proportional hazards regression models were used to assess the effect of MetS in terms of a dichotomous classification, each individual component and the number of components for males and females.Colorectal adenoma was present in 2.7% (n = 652) of male participants and 1.1% (n = 403) of female participants. The prevalence rate of MetS was 26.7% and 23.3% for males and females, respectively. The effect of MetS on colorectal adenoma was statistically significant and similar for the 2 genders, with an adjusted hazard ratio (aHR) of 1.33 (95% CI: 1.13-1.58) in males and 1.33 (95% CI: 1.06-1.66) in females after adjustment for confounders. However, MetS led to higher risk of advanced colorectal adenoma in men than in women. Regarding the effect of each component of MetS on colorectal adenoma, abnormal waist circumference and hypertriglyceridemia led to an elevated risk of colorectal adenoma in both genders. A rising risk of colorectal adenoma among females was noted in those with a moderately higher level of glycemia (100-125 mg/dL, aHR = 1.44, 95% CI: 1.12-1.85). Hypertriglyceridemia and high blood pressure were associated with an increased risk of advance colorectal adenoma in males.Both male and female subjects with MetS had a higher risk of colorectal adenoma. The contributions from individual components of MetS varied by gender. These findings suggest that the possible risk reduction of colorectal adenoma through metabolic syndrome-based lifestyle modifications may differ between genders.

The significant interaction between age and diabetes mellitus for colorectal cancer: Evidence from NHANES data 1999-2016

BACKGROUND

Diabetes mellitus has been associated with elevated risk of colorectal cancer (CRC), although interaction between age and DM is unclear. We examined the relationship among DM, CRC and age.

METHODS

22,580 subjects aged ≥18 years were identified from the National Health and Nutrition Examination Survey (NHANES) database collected between 1999-2016. To account for the complex, stratified, multistage probability sampling design in NHANES, SASv9.4 Procedure Survey Methodology was applied. Univariate analysis compared individual baseline characteristics between subjects with and without DM. Multivariate logistic regression model assessed association between DM and CRC, in which the model included factors with p<0.05 in univariate analysis as covariates.

RESULTS

Univariate analysis showed significant differences in age (p<0.0001), race (p<0.0001), smoking (p=0.0023) and body mass index (p<0.0001) between No-DM and DM. Multivariate analysis revealed significant interaction between age and DM (p=0.0004). Subjects with DM aged 18-65 were more likely to experience CRC (OR=4.47, 95%CI=(1.33-15.07); p=0.0157) compared to those without DM. Subjects with DM aged >65 were not at increased risk for CRC (OR=0.83, 95%CI=(0.43-1.59); p=0.5665) compared to those without DM.

CONCLUSIONS

Age, DM, and interaction between age and DM are risk factors for CRC. Individuals with DM aged 18-65 years have a higher CRC risk.

Effect of ambient air pollution on the incidence of colorectal cancer among a diabetic population: a nationwide nested case-control study in Taiwan

OBJECTIVES

An increasing number of studies had shown that air pollution exposure may aggravate blood glucose control in patients with diabetes, an independent risk factor for colorectal cancer (CRC) proposed by some researchers. This study aimed to investigate the impact of exposure to ambient particulate matter with aerodynamic diameters ≤2.5 μm (PM_2.5) on the incidence of CRC among a diabetic population.

DESIGN

A nested case-control study.

SETTING

A subset data retrieved from the Taiwan's National Health Insurance Research Database.

PARTICIPANTS

We identified patients with newly diagnosed diabetes (n=1 164 962) during 1999-2013. Participants who had subsequently developed an incident of CRC were placed into the case group, while controls were matched to the cases at a 4:1 ratio by age, gender, date of diabetes diagnosis and the index date of CRC diagnosis.

METHODS AND OUTCOME MEASURES

All variables associated with the risk of CRC entered into a multinomial logistic regression model. The dose-response relationship between various average concentrations of PM_2.5 exposure and the incidence of CRC was estimated by logistic regression.

RESULTS

The study included a total of 7719 incident CRC cases matched with 30 876 controls of random sampling. The mean annual concentration of PM_2.5 was 35.3 µg/m³. After adjusting for potential confounders, a dose-response relationship was observed between the CRC risks and each interquartile increase of PM_2.5 concentration (Q1-Q2: 1.03 (0.95-1.11), Q2-Q3: 1.06 (0.98-1.15), ≥Q3: 1.19 (1.10-1.28) in model 2. The adjusted ORs (95% CI) of CRC incidence for each 10 µg/m³ increment of PM_2.5 was 1.08 (1.04-1.11). Moreover, a faster growing adapted Diabetes Complications Severity Index (aDCSI) score was noticed in CRC group compared with the controls, which also showed a significant association in our multivariate analysis (adjusted OR=1.28, 95% CI 1.18 to 1.38).

CONCLUSIONS

Long-term exposure to high concentrations of PM_2.5 may contribute to an increased incidence of CRC among diabetic populations.

The Confounders of Cancer Immunotherapy: Roles of Lifestyle, Metabolic Disorders and Sociological Factors

Checkpoint blockade immunotherapy (CPI) is an effective treatment option for many types of cancers. Irrespective of its wide clinical implications, the overall efficacy remains unpredictable and even poor in certain pathologies such as breast cancer. Thus, it is imperative to understand the role of factors affecting its responsiveness. In this review, we provide an overview on the involvement of sociological factors, lifestyles and metabolic disorders in modulating the CPI response in patients from multiple malignancies. Lifestyle habits including exercise, and diet promoted therapeutic responsiveness while alcohol consumption mitigated the CPI effect by decreasing mutational burden and hampering antigen presentation by dendritic cells. Metabolic disorder such as obesity was recognized to enhance the PD-1 expression while diabetes and hypertension were consequences of CPI therapy rather than causes. Among the sociologic factors, sex and race positively influenced the CPI effectiveness on account of increased effector T cell activity and increased PD-1 expression while ageing impaired CPI responsiveness by decreasing functional T cell and increased toxicity. The combined effect of these factors was observed for obesity and gender, in which obese males had the most significant effect of CPI. Therefore these variables should be carefully considered before treating patients with CPI for optimal treatment outcome.

Correlation between Expression Profiles of Key Signaling Genes in Colorectal Cancer Samples from Type 2 Diabetic and Non-Diabetic Patients

Several lines of epidemiological and biochemical evidence support the association of type 2 diabetes mellitus (T2DM) and colorectal cancer (CRC). T2DM has been shown to impinge on the transcriptome of colon tumor cells, promoting their proliferation and invasion. In order to gain insight into diabetes-specific modulation of colon cancer signaling, we analyzed gene expression patterns of more than five hundred genes encoding signaling proteins on TaqMan OpenArray panels from colonoscopic colorectal tumor samples of type 2 diabetic and non-diabetic patients. In total, 48 transcripts were found to be differentially expressed in tumors of T2DM patients as compared to healthy colon samples. Enrichment analysis with the g:GOSt (Gene Ontology Statistics) functional profiling tool revealed that the underlying genes can be classified into five signaling pathways (in decreasing order of significance: Wnt (wingless-type)/β-catenin; Hippo; TNF (tumor necrosis factor); PI3K/Akt (phosphoinositide-3 kinase/protein kinase B), and platelet activation), implying that targeted downregulation of these signaling cascades might help combat CRC in diabetic patients. Transcript levels of some of the differentially expressed genes were also measured from surgically removed diabetic and non-diabetic CRC specimens by individual qPCR (quantitative real-time PCR) assays using the adjacent normal tissue mRNA levels as an internal control. The most significantly altered genes in diabetic tumor samples were largely different from those in non-diabetic ones, implying that T2DM profoundly alters the expression of signaling genes and presumably the biological characteristics of CRC.

The Combined Impact of Chronic Kidney Disease and Diabetes on the Risk of Colorectal Cancer Depends on Sex: A Nationwide Population-Based Study

PURPOSE

Although both chronic kidney disease (CKD) and diabetes mellitus (DM) are considered factors increasing the risk of colorectal cancer (CRC), their impact on CRC is not fully understood. This study was aimed to investigate the impact of CKD, DM, or both diseases on the risk of CRC and to evaluate sex differences therein.

MATERIALS AND METHODS

Using data from the National Health Insurance Service-Health Examination Cohort in Korea, we conducted a 1:2 matched case-control study. The disease groups consisted of CKD-/DM+ (n=17700), CKD+/DM- (n=22643), and CKD+/DM+ groups (n=8506). After 1:2 matching by age, sex, and health examination year and month, the healthy control group consisted of 97698 individuals.

RESULTS

Multivariate Cox regression analysis showed that the CKD-/DM+, CKD+/DM-, and CKD+/DM+ groups were independently associated with an increased incidence of CRC, compared with controls [hazard ratio (HR), 1.34, 1.31, and 1.63, respectively; all p<0.001]. Compared to the controls, adjusted HRs for the cumulative incidence of CRC in the CKD-/DM+, CKD+/DM-, and CKD+/DM+ groups were, respectively, 1.32, 1.26, and 1.43 in male and 1.38, 1.39, and 2.00 in female. The HR for CRC incidence was significantly higher for the CKD+/DM+ group than for the CKD-/DM+ or CKD+/DM- group in female; however, this significant difference was not observed in male.

CONCLUSION

In female, having both CKD and DM significantly increases the risk of CRC, compared with having CKD or DM alone. This study suggests a significant difference in the effect of CKD or DM on the risk of CRC according to sex.

The incidence and patterns of colorectal cancers in Sri Lanka from 2001 to 2010: Analysis of national cancer registry data

OBJECTIVES

The incidence of colorectal cancer (CRC) has been increasing in many Asian countries. This study aims to analyse trends in CRC incidence and histological patterns in Sri Lanka.

METHODS

All newly diagnosed patients with CRC in Sri Lanka during 2001-2010 included in the National Cancer Registry were analysed for trends in incidence using Joinpoint regression software.

RESULTS

A total of 7,694 CRC (male:female = 1.02:1, mean age = 58.7 years) were analysed. The incidence of CRC in Sri Lanka has increased from a WHO age-standardised rate of 2.9/100,000 in 2001 (95%-confidence interval [95%-CI]: 2.64-3.16) to 6.08/100,000 in 2010 (95%-CI: 5.71-6.44). This is an estimated annual percentage change (EAPC) of 8.9 (95%-CI: 7.5-10.4). The proportional increase in incidence was observed to be greater for females (2.8 to 5.6, EAPC: 9.4 (95%-CI: 7.7-11.2), p < .05) than males (3.02 to 6.62, EAPC: 8.5 (95%-CI: 6.9-10.2), p < .05).

CONCLUSIONS

Similar to other Asian countries, a significant increase in the incidence of CRC was observed in Sri Lanka. Rate of the increase may have been artificially inflated due to better case reporting and diagnostic scrutiny. Future studies focussing on trends in tumour stage and fatality will help shed light on changing patterns in the burden of CRC in Sri Lanka.

Insulin enhances and metformin reduces risk of colorectal carcinoma in type-2 diabetes

BACKGROUND

Identifying colorectal cancer associated risks is important for conducting a program for the survey and prevention of colorectal cancer.

AIM

To investigate the association between use of insulin or metformin with colorectal cancer (CRC) in type 2 diabetes (T2DM).

DESIGN

Population-based cohort study.

METHODS

Through analysis of National Health Insurance (NHI) database between 1998 and 2010 in Taiwan, we identified 66 324 T2DM patients aged ≥ 20 years and selected subjects without diabetes by 1: 1 randomly matching with the study cohort based on age, sex and index date. We followed up the participants until 31 December 2011 or when they withdrew from the NHI program.

RESULTS

Compared with non-diabetic subjects, the T2DM patients exhibited an increased risk of CRC [adjusted HR (aHR) = 1.56, 95% confidence interval (CI) = 1.39-1.75], after adjustment for age, sex, urbanization level, comorbidities and examinations of colonoscopy, sigmoidoscopy, or stool occult blood test. Among the T2DM patients, insulin usage increased the risk of CRC (aHR = 1.86, 95% CI = 1.58-0-2.19) after adjustment for age, sex, urbanization level, comorbidities, metformin usage and examinations; nevertheless, metformin decreased the risk of CRC (aHR = 0.65, 95% CI = 0.54-0.77) after adjustment for age, sex, urbanization level, comorbidities, insulin usage and examinations. Compared with the non-insulin cohort, the risk of CRC tended to increase with the incremental dosage of insulin exposure.

CONCLUSION

Our population-based cohort study demonstrated an association between T2DM and CRC. Among the T2DM patients, insulin use was associated with an increased risk of CRC and metformin use was associated with a decreased risk of CRC. Inability to obtain information on several potential confounding factors, such as lifestyle and dietary habits, is the major limitation of the study.

Predictors of Survival Among Colorectal Cancer Patients in a Low Incidence Area

Background

Colorectal cancer is the third most common malignancy in Saudi Arabia. The best therapeutic regimen for colorectal cancer is a matter of ongoing debate and data on its treatment in Saudi Arabia are limited.

Purpose

The objective of this study was to explore the predictors of survival and to compare the risk of mortality among colorectal cancer patients treated with different therapeutic modalities.

Patients and Methods

The study utilized data from the electronic colorectal cancer registry of a university-affiliated tertiary care hospital. The Kaplan-Meier survival analysis was used to estimate the survival rates over 36 months of follow-up across rectal and colon cancer patients as well as different sociodemographic and medical characteristics. Bivariate and multiple Cox proportional-hazards regressions were conducted to estimate the risk of mortality among rectal and colon cancer patients undergoing different treatments.

Results

The number of patients in the registry who were followed up for 36 months was 143 patients. The majority of patients had colon cancer (74.13%). Rectal cancer patients had generally better survival estimates compared to their colon cancer counterparts. Colon cancer patients treated with chemotherapy had a significantly lower risk of mortality controlling for the use of surgery, radiotherapy, and other variables including age, gender, stage of cancer, and family history of colorectal cancer (HR=0.33; P=0.03). Additionally, colon cancer patients with a family history of colorectal cancer had significantly higher risk of mortality (HR=3.40; P=0.02).

Conclusion

The findings of this study highlight the value of chemotherapy in managing colon cancer patients.

Effects of Family History on Relative and Absolute Risks for Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Guidelines recommend that individuals with familial colorectal cancer undergo colonoscopy surveillance instead of average-risk screening. However, these recommendations vary widely. To substantiate appropriate surveillance strategies, precise and valid evidence-based risk estimates are needed for individuals with a family history of colorectal cancer (CRC).

METHODS

We systematically searched MEDLINE, EMBASE, and Cochrane from inception to July 2018 for case-control and cohort studies investigating the effect of family history on CRC risk. We calculated summary estimates of pooled relative risks (RRs) using a random-effects model. Life tables were created to convert RR estimates into absolute risk estimates.

RESULTS

We screened 4417 articles and identified 42 eligible case-control and 20 cohort studies. In case-control studies, the RR for CRC in patients with 1 first-degree relative (FDR with CRC) was 1.92 (95% CI, 1.53-2.41) and 1.37 (95% CI, 0.76-2.46) for cohort studies. For individuals with 2 or more FDRs with CRC, the RR was 2.81 in case-control studies (95% CI, 1.73-4.55) and 2.40 in cohort studies (95% CI, 1.76-3.28). For individuals having a FDR diagnosed with CRC at an age younger than 50 years, the RR for CRC in their FDRs was 3.57 in case-control studies (95% CI, 1.07-11.85) and 3.26 in cohort studies (95% CI, 2.82-3.77). The cumulative absolute risks for CRC at 85 years in Western Europe were 4.8% for persons with 1 FDR with CRC (95% CI, 2.7%-8.3%), 8.2% for individuals with 2 or more FDRs (95% CI, 6.1%-10.9%), and 11% for persons with a FDR diagnosed with CRC at an age younger than 50 years (95% CI, 9.5%-12.4%).

CONCLUSIONS

In this systematic review and meta-analysis, we found that the RR of CRC among FDRs is lower than previously expected, especially based on cohort studies. Risk estimates are affected by the number of relatives with CRC and their age at diagnosis. Intensified colonoscopy surveillance strategies could be considered for high-risk groups. PROSPERO trial identification no: CRD42018103058.

Influence and mechanism of miR-99a suppressing development of colorectal cancer (CRC) with diabetes mellitus (DM)

OBJECTIVE

This study aimed to identify the changes of miRNAs in colorectal cancer (CRC) complicated with diabetes mellitus (DM) (CRC + DM) tissues and their potential effects.

METHODS

The changes of miRNAs in CRC + DM tissues were determined by miRNA microarray. The expression levels of miR-99a in 40 clinical specimens and 6 CRC cell lines were determined by qRT-PCR. The capacity for miR-99a to induce cell proliferation and invasion was examined with miR-99a-overexpressing HCT-116 cells. The relative mTOR mRNA and protein levels were determined by qRT-PCR and Western blotting, respectively, in HCT-116 cells transfected with miR-99a. The dual luciferase assay was performed to confirm the direct regulation of miR-99a on mTOR 3'-UTR. The HCT-116 cells were treated with 100 mg/L advanced glycation end products (AGEs); then, the mTOR expression levels were determined by qRT-PCR, Western blotting, and immunohistochemistry.

RESULTS

Seventeen miRNAs were found to be differentially expressed among normal tissue, CRC tissue, and CRC with DM tissue, including 15 upregulated and 2 downregulated with fold changs of more than 2 times. qRT-PCR confirmed that miR-99a was downregulated in CRC and CRC + DM tissues. In addition, miR-99a overexpression remarkably impaired CRC cell proliferation and metastasis, and negatively regulated mTOR signaling through direct binding to the 3'-UTR of mTOR. AGEs could suppress miR-99a and stimulate mTOR signaling in CRC cells. Increased mTOR was also identified in CRC with DM tissues.

CONCLUSION

Our findings indicate that miR-99a is a potential marker and therapeutic target of CRC complicated with DM, and that AGEs impair miR-99a-overactivated mTOR signaling in CRC with DM patients, which promotes CRC development.

Diabetes Mellitus and Colon Carcinogenesis: Expectation for Inhibition of Colon Carcinogenesis by Oral Hypoglycemic Drugs

The global deaths due to colorectal cancer and diabetes mellitus have increased by 57% and 90%, respectively. The relationship between various cancers and diabetes mellitus has been shown in multiple epidemiological studies. Hence, better management of diabetes mellitus is expected to reduce the risk of various cancers. This review focuses on colorectal cancer and aims to summarize recent findings on the antitumor effects of various oral hypoglycemic drugs on colorectal cancer and their estimated mechanisms. Of the seven classes of oral hypoglycemic agents, only metformin was found to have suppressive effects on colorectal cancer in both clinical and basic research. Clinical and basic researches on suppressing effects of glinides, dipeptidyl peptidase-4 inhibitors, thiazolidinedione, α-glucosidase inhibitors, and sodium glucose cotransporter-2 inhibitors against colon carcinogenesis have been insufficient and have not arrived at any conclusion. Therefore, further research regarding these agents is warranted. In addition, the suppressive effects of these agents in healthy subjects without diabetes should also be investigated.

Diabetes mellitus and cancer incidence: the Atherosclerosis Risk in Communities (ARIC) cohort study

PURPOSE

To assess the association between diabetes mellitus (DM) and the incidence of cancer at different sites.

METHODS

Data from the baseline and first three follow-up visits of the Atherosclerosis Risk in Communities (ARIC) study, an ongoing cohort study of adults from four American communities, were used in this study. Of 15,792 persons aged 45-64 years old who participated in the baseline visit, the data of 15,118 participants were available for this study. For each cancer site, a conditional stratified Poisson regression model was fitted to estimate the adjusted relative rate and 95% confidence interval (adj. RR, 95% CI) of its incidence in diabetics compared to non-diabetics.

RESULTS

We excluded 850 participants with a history of cancer at baseline and 149 participants who developed cancer during 2 years after enrollment, leaving a total of 14,119 participants of whom 1721 were diabetics. Independent of age, body mass index, alcohol consumption, and physical activity, DM decreased the risk of all cancers combined (adj. RR: 0.77, 95% CI: 0.60, 0.98) and the risk of prostate cancer (adj. RR: 0.51, 95% CI: 0.27, 0.97) and increased the risk of colorectal cancer in non-menopausal women (adj. RR: 12.08, 95% CI: 2.06, 70.94).

CONCLUSIONS

In conclusion, DM may be associated with an increased risk of colorectal cancer in non-menopausal women and a decreased risk of prostate cancer and all cancers combined.

Lower Relative Contribution of Positive Family History to Colorectal Cancer Risk with Increasing Age: A Systematic Review and Meta-Analysis of 9.28 Million Individuals

OBJECTIVES

Existing algorithms predicting the risk of colorectal cancer (CRC) assign a fixed score for family history of CRC. Whether the increased CRC risk attributed to family history of CRC was higher in younger patients remains inconclusive. We examined the risk of CRC associated with family history of CRC in first-degree relative (FDR) according to the age of index subjects (<40 vs. ≥40; <50 vs. ≥50; and <60 vs. ≥60 years).

METHODS

Ovid Medline, EMBASE, and gray literature from the reference lists of all identified studies were searched from their inception to March 2017. We included case-control/cohort studies that investigated the relationship between family history of CRC in FDR and prevalence of CRC. Two reviewers independently selected articles according to the PRISMA guideline. A random effects meta-analysis pooled relative risks (RR).

RESULTS

We analyzed 9.28 million subjects from 63 studies. A family history of CRC in FDR confers a higher risk of CRC (RR = 1.76, 95% CI = 1.57-1.97, p < 0.001). This increased risk was higher in younger individuals (RR = 3.29, 95% CI = 1.67-6.49 for <40 years versus RR = 1.42, 95% CI = 1.24-1.62 for ≥40 years, p = 0.017; RR = 2.81, 95% CI = 1.94-4.07 for <50 years versus RR = 1.47, 95% CI = 1.28-1.69 for ≥50 years, p = 0.001). No publication bias was identified, and the findings are robust in subgroup analyses.

CONCLUSIONS

The increase in relative risk of CRC attributed to family history was found to be higher in younger individuals. Family history of CRC could be assigned a higher score for younger subjects in CRC risk prediction algorithms. Future studies should examine if such approach may improve their predictive capability.

Efficacy and tolerability of various bowel preparations in diabetic patients: a randomized controlled trial

Background and study aims  Diabetes mellitus (DM) is an independent risk factor for poor bowel preparation prior to colonoscopy. Bisacodyl is a stimulant laxative that may mitigate colonic dysmotility associated with diabetes. We hypothesized that adding bisacodyl to split-dose bowel preparation (SDBP) would improve the quality of bowel preparation among patients with diabetes. Patients and methods  Adult outpatients aged 18 to 80 years undergoing colonoscopy were recruited. One hundred and eighty-six patients with diabetes were randomly assigned to 1 of 3 treatment arms: 1) conventional 4 L of polyethylene glycol electrolyte lavage solution (PEG-ELS; conventional bowel preparation [CBP]); 2) split-dose of 4 L PEG-ELS (split-dose bowel preparation [SDBP]); or 3) split-dose of 4 L PEG-ELS preceded by 10 mg of oral bisacodyl 10 (SDBP-B). The primary outcome measure was bowel cleansing as indicated by Boston Bowel Preparation Scale (BBPS) score. Endoscopists were blinded to the preparation used. Secondary outcome measures were safety and patient tolerability. Results  Of the 212 patients randomized, only 186 received assigned bowel preparation. There were no differences among the three study groups with regard to age, indication, duration of DM, insulin use, narcotic use, or presence of end-organ diabetic complications. There was a trend toward better bowel preparation quality among those receiving SDBP and SDBP-B compared to those receiving CBP, but the trend was not statistically significant  ≥ 6 BBPS; 67 % vs. 83 % vs. 75 %, P  = 0.1). In terms of safety and tolerability, there were no differences among the three groups. Conclusion  Adding bisacodyl to SDBP does not improve the quality of bowel preparation in patients with DM. Further efforts are needed to optimize colonoscopy bowel preparation in this population.

Sex differences in the association between diabetes and cancer: a systematic review and meta-analysis of 121 cohorts including 20 million individuals and one million events

AIMS/HYPOTHESIS

Diabetes has been shown to be a risk factor for some cancers. Whether diabetes confers the same excess risk of cancer, overall and by site, in women and men is unknown.

METHODS

A systematic search was performed in PubMed for cohort studies published up to December 2016. Selected studies reported sex-specific relative risk (RR) estimates for the association between diabetes and cancer adjusted at least for age in both sexes. Random-effects meta-analyses with inverse-variance weighting were used to obtain pooled sex-specific RRs and women-to-men ratios of RRs (RRRs) for all-site and site-specific cancers.

RESULTS

Data on all-site cancer events (incident or fatal only) were available from 121 cohorts (19,239,302 individuals; 1,082,592 events). The pooled adjusted RR for all-site cancer associated with diabetes was 1.27 (95% CI 1.21, 1.32) in women and 1.19 (1.13, 1.25) in men. Women with diabetes had ~6% greater risk compared with men with diabetes (the pooled RRR was 1.06, 95% CI 1.03, 1.09). Corresponding pooled RRRs were 1.10 (1.07, 1.13) for all-site cancer incidence and 1.03 (0.99, 1.06) for all-site cancer mortality. Diabetes also conferred a significantly greater RR in women than men for oral, stomach and kidney cancer, and for leukaemia, but a lower RR for liver cancer.

CONCLUSIONS/INTERPRETATION

Diabetes is a risk factor for all-site cancer for both women and men, but the excess risk of cancer associated with diabetes is slightly greater for women than men. The direction and magnitude of sex differences varies by location of the cancer.

Diabetes mellitus and the risk of gastrointestinal cancer in women compared with men: a meta-analysis of cohort studies

Background

The increasing epidemic proportions of diabetes mellitus (DM) are a major cause of premature illness and death. However, whether DM confers the same excess risk of gastrointestinal cancer for women as it does for men remains controversial. The purpose of this study was to estimate the relation between DM and gastrointestinal cancer in women compared with men after accounting for other major risk factors based on cohort studies.

Methods

We performed a meta-analysis of cohort studies published through May 2017 from PubMed, Embase, and the Cochrane Library. Studies with cohort designs were stratified by sex and reported the relation between DM and esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), colon cancer (CC), rectal cancer (RC), hepatocellular carcinoma (HCC), or pancreatic cancer (PC) risk. The ratio of relative risk (RRR) between men and women was employed to measure the sex differences in the relation between DM and gastrointestinal cancer with a random effects model with inverse variance weighting.

Results

We included 38 cohort studies reporting data on 18,060,698 individuals. The pooled RRR indicated DM women was associated with an increased risk of GC (RRR: 1.14; 95%CI: 1.06–1.22; p < 0.001), while the risk of HCC was lower (RRR: 0.88; 95%CI: 0.79–0.99; p = 0.031) as compared with DM men. Further, there was no evidence of sex differences in the RRR between participants who had DM compared with those without DM for EC (p = 0.068), CRC (p = 0.618), and PC (p = 0.976). In addition, the pooled RRR showed a statistically significant association between DM and the risk of CC in women compared with men (RRR: 0.93; 95%CI: 0.86–1.00; p = 0.050), and there was no evidence of sex differences for RC among participants with DM compared to those without DM (p = 0.648). Finally, the sex differences of the comparison between DM and non-DM for gastrointestinal cancer risk at different sites were variable after stratification for different effect estimates.

Conclusions

The findings of this study suggested female-to-male RRR of DM was increased for GC, while reduced for HCC and CC. However, there were no sex differences for the relation between DM and the risk of EC, CRC, PC, and RC.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4351-4) contains supplementary material, which is available to authorized users.

Factors Associated with Colorectal Cancer Among Jordanians: a Case- Control Study

Objective: In recent years, the incidence of colorectal cancer (CRC) in Jordan has been on the rise. We aimed to determine associations with lifestyle factors, demographic and clinical variables. Methods: This case-control study included 102 patients diagnosed with CRC and 198 age and gender matched healthy subjects as controls. Cases were purposefully sampled; however, the control group were selected by simple random sampling of a cross-section of the population in Northern Jordan. Participating cases and controls completed an anonymous questionnaire inquiring about their demographic characteristics, lifestyle factors, and clinical variables. Data about the medical history and diagnosis of participating cases were obtained from the cases themselves and confirmed by reviewing their medical records. Results: In the cross tabulation analysis, the Chi square test showed that diabetes and hypertension were significantly associated with CRC (P <0.05). Additionally, regression modeling revealed that age ≥ 45 years (OR=10.93), positive family history for CRC (OR=5.53), physical inactivity (OR=7.4), cigarette smoking (OR=3.71), and having other types of cancer (OR=13.61) were all associated with increased risk of CRC. Conclusions: Physical inactivity and cigarette smoking are among the top modifiable risk factors for CRC among Jordanians. Moreover, diabetes and hypertension were found to be statistically significant risk factors in univariate, but not multivariate analysis. More effective strategies for elevating awareness and prevention are required at both national and international levels. Improving screening strategies is needed for early detection of CRC in Jordan.

Pioglitazone and the Risk of Bladder Cancer: A Meta-Analysis

People with type 2 diabetes are at increased risk of bladder cancer. Pioglitazone is said to increase it further, although published evidence is mixed. We conducted a meta-analysis to determine if any link between the use of pioglitazone and an increased risk of bladder cancer can be found. A comprehensive literature search was conducted through electronic databases as well as registries for data of clinical trials to identify studies that investigate the effect of pioglitazone on bladder cancer in diabetic patients. We used the risk ratio (RR) and the hazard ratio (HR) provided by the studies to illustrate the risk of occurrence of bladder cancer in the experimental group compared to that in the control group. Fourteen studies using RR and 12 studies using HR were included in the analysis. The overall RR was 1.13 with 95% CI (0.96-1.33) with low heterogeneity among the studies using RR, suggesting that no connection exists between use of pioglitazone and the risk of bladder malignancy. The summary HR was 1.07 (0.96-1.18) allowing us to affirm that there is no link between long-term use of pioglitazone and bladder cancer. Our results support the hypothesis of no difference in the incidence of bladder cancer among the pioglitazone group and the nonuser group. Our conclusion is that the explanation of hypothetically increased risk of bladder malignancy should be attributed to other factors.

FUNDING

Tchaikapharma High Quality Medicines Inc.

Diabetes-induced mechanophysiological changes in the small intestine and colon

The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.

2017 update on the relationship between diabetes and colorectal cancer: epidemiology, potential molecular mechanisms and therapeutic implications

Worldwide deaths from diabetes mellitus (DM) and colorectal cancer increased by 90% and 57%, respectively, over the past 20 years. The risk of colorectal cancer was estimated to be 27% higher in patients with type 2 DM than in non-diabetic controls. However, there are potential confounders, information from lower income countries is scarce, across the globe there is no correlation between DM prevalence and colorectal cancer incidence and the association has evolved over time, suggesting the impact of additional environmental factors. The clinical relevance of these associations depends on understanding the mechanism involved. Although evidence is limited, insulin use has been associated with increased and metformin with decreased incidence of colorectal cancer. In addition, colorectal cancer shares some cellular and molecular pathways with diabetes target organ damage, exemplified by diabetic kidney disease. These include epithelial cell injury, activation of inflammation and Wnt/β-catenin pathways and iron homeostasis defects, among others. Indeed, some drugs have undergone clinical trials for both cancer and diabetic kidney disease. Genome-wide association studies have identified diabetes-associated genes (e.g. TCF7L2) that may also contribute to colorectal cancer. We review the epidemiological evidence, potential pathophysiological mechanisms and therapeutic implications of the association between DM and colorectal cancer. Further studies should clarify the worldwide association between DM and colorectal cancer, strengthen the biological plausibility of a cause-and-effect relationship through characterization of the molecular pathways involved, search for specific molecular signatures of colorectal cancer under diabetic conditions, and eventually explore DM-specific strategies to prevent or treat colorectal cancer.

Inadequate Bowel Cleansing Efficacy of Split-dose Polyethylene Glycol for Colonoscopy in Type 2 Diabetic Patients: A Prospective and Blinded Study

BACKGROUND/AIMS

Split-dose polyethylene glycol (PEG) is considered a standard bowel preparation regimen for colonoscopy in the general population. However, it is not clear whether the regimen is optimal for colonoscopy in diabetic patients. The aim of this study was to compare the efficacy and tolerability of split-dose PEG for diabetic versus nondiabetic patients.

METHODS

This is a single-center, prospective, investigator-blinded study. A total of 55 consecutive nondiabetic and 50 diabetic patients ingested 2 L PEG solution on the day before the procedure and then 2 L of the solution on the day of colonoscopy. The quality of bowel preparation was graded using the Ottawa scale.

RESULTS

There was a significant difference in bowel preparation quality, with a worse preparation except for mid colon in diabetic group (total score: 7.06±1.69 vs. 5.54±1.97, P<0.001; right colon: 2.28±0.57 vs. 1.81±0.72, P<0.001; mid colon: 1.70±0.54 vs. 1.56±0.66, P=0.253; rectosigmoid colon: 1.70±0.76 vs. 1.14±0.62, P<0.001; fluid volume: 1.38±0.53 vs. 1.01±0.59, P=0.001). About 70% of nondiabetic patients had an adequate preparation compared with only 40% of diabetic patients (P=0.003). Diabetic group had longer cecal intubation time (6.4±3.6 vs. 4.5±2.4, P=0.002) and total procedure time (22.1±7.6 vs. 18.1±8.5, P=0.015). Compliance and adverse events were not significantly different. In diabetic group, inadequate bowel preparation had a significant association with higher fasting plasma glucose (136.9±21.8 vs. 121.8±19.4 mg/dL, P=0.016).

CONCLUSIONS

Diabetic patients had a worse preparation quality and longer cecal intubation and total procedure time compared with nondiabetic patients. These data suggest that split-dose PEG preparation regimen is not sufficient for optimal bowel preparation in diabetic patients undergoing colonoscopy.

Hyperglycemia, tumorigenesis, and chronic inflammation

Hyperglycemia is the most prominent sign that characterizes diabetes. Hyperglycemia favors malignant cell growth by providing energy to cancer cells. Clinical studies also showed an increased risk of diabetes being associated with different types of cancers. In addition, poorly regulated glucose metabolism in diabetic patients is often found with increased levels of chronic inflammatory markers, e.g., interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, and emerging evidence has highlighted activation of the immune response in the progression and development of cancer cells. Therefore, uncontrolled proinflammatory responses could conceivably create a chronic inflammatory state, promoting a tumor-favorable microenvironment and potentially triggering immune overactivation and cancer growth. To further understand how hyperglycemia contributes to immune overactivation, the tumor microenvironment and the development of chronic inflammation-associated tumors may provide insights into tumor biology and immunology. This paper provides a brief introduction to hyperglycemia-associated diseases, followed by a comprehensive overview of the current findings of regulatory molecular mechanisms of glycosylation on proteoglycans in the extracellular matrix under hyperglycemic conditions. Then, the authors discuss the role of hyperglycemia in tumorigenesis (particularly in prostate, liver, colorectal, and pancreatic cancers), as well as the contribution of hyperglycemia to chronic inflammation. The authors end with a brief discussion on the future perspectives of hyperglycemia/tumorigenesis and potential applications of alternative/effective therapeutic strategies for hyperglycemia-associated cancers.

Diabetes Mellitus and Risk of Colorectal Cancer Mortality in Japan: the Japan Collaborative Cohort Study

Objective: Our aim was to estimate whether diabetes mellitus (DM) may be associated with an increased risk of colorectal cancer (CRC) mortality in Japan. Methods: The Japan Collaborative Cohort (JACC) Study is a nationwide prospective study, initiated in 1988, which involves 110,585 subjects (age range: from 40 to 79 years; 46,395 males and 64,190 females). Our present analysis population comprised 96,081 (40,510 men and 55,571 women) who provided details on DM history. The questionnaire also included age, sex, weight, height, family history of CRC, smoking, drinking and exercise habits, and education. Cox proportional-hazard regression was used to estimate the hazard ratio (HR). We used SPSS 21 software to analyze all data. Results: Among the participants with DM, we followed up for 71,174 person-years and 640. deaths from CRC were confirmed; and, among the non-diabetic participants, 785 CRC deaths were identified during 1,499,324 person-years. After adjusting for multivariate confounding factors, such as age, sex, body mass index (BMI), family history of colorectal cancer, smoking habit, drinking habit, physical activity (sports and walking) and education, DM was associated with an increased risk of CRC death (HR 1.4, 95% confidence interval [CI] 1.0-2.0). Diabetic women, but not diabetic men, experienced increased mortality from CRC (HR 1.7, 95% CI 1.0-3.0). Conclusion: The risk of CRC mortality is significantly increased in both sexes and women with diabetes, but no significant increase was seen for diabetic men among Japanese.

Type 2 diabetes mellitus and risk of colorectal adenoma: a meta-analysis of observational studies

BACKGROUND

To summarize the relationship between type 2 diabetes mellitus (T2DM) and risk of colorectal adenomas (CRA), we performed a meta-analysis of observational studies.

METHODS

To find studies, we searched PubMed, Embase, the Cochrane Library, Web of Science and conference abstracts and related publications for American Society of Clinical Oncology and the European Society of Medical Oncology. Studies that reported relative risks (RRs) or odds ratios (ORs) with 95 % confidence intervals (CIs) for the association between T2DM and risk of CRA were included. The meta-analysis assessed the relationships between T2DM and risk of CRA. Sensitivity analyses were performed in two ways: (1) by omitting each study iteratively and (2) by keeping high-quality studies only. Publication bias was detected by Egger's and Begg's tests and corrected using the trim and fill method.

RESULTS

This meta-analysis included 17 studies with 28,999 participants and 6798 CRA cases. We found that T2DM was a risk factor for CRA (RR: 1.52; 95 % CI: 1.29-1.80), and also for the advanced adenoma (RR: 1.41; 95 % CI: 1.06-1.87). Patients with existing T2DM (RR: 1.56; 95 % CI: 1.16-2.08) or newly diagnosed T2DM (RR: 1.51; 95 % CI: 1.16-1.97) have a risk of CRA. Similar significant results were found in retrospective studies (RR: 1.57; 95 % CI: 1.30-1.89) and population based cross-sectional studies (RR: 1.46; 95 % CI: 1.21-1.89), but not in prospective studies (RR: 1.27; 95 % CI: 0.77-2.10).

CONCLUSIONS

Our results suggested that T2DM plays a risk role in the risk of developing CRA. Consequently, medical workers should increase the rate of CRA screening for T2DM patients so that they can benefit from behavioural interventions that can help prevent the development of colorectal cancer. Additional, large prospective cohort studies are needed to make a more convincing case for these associations.

Diabetes mellitus increases the risk of colorectal neoplasia: An updated meta-analysis

OBJECTIVE

Recent studies proved that patients with diabetes were at significantly higher risk of developing colorectal cancer. However, the association between diabetes mellitus and the risk of colorectal adenoma remains undefined. Thus we conducted an updated meta-analysis to identify the association between diabetes mellitus and the risk of colorectal neoplasia including adenoma and cancer.

METHODS

We conducted a search in databases including Pubmed, Web of Science, EMBASE Databases, Cochrane CENTRAL, Wanfang Data, and CNKI database. Case-control and cohort studies were included. All articles were published before January 2015 and the quality of each study was evaluated by the Newcastle-Ottawa Scale. Odds ratios (ORs) or relative risks (RRs) and its corresponding 95% confidence intervals (CIs) for each study were calculated and summary relative risk estimates with corresponding 95% CIs were generated using the random-effects model. Heterogeneity and publication bias were assessed.

RESULTS

Twenty-nine articles including ten case-control studies and nineteen cohort studies were included in this meta-analysis. In a pooled analysis of all studies, diabetes mellitus was associated with increased risk of colorectal neoplasia (RR=1.35, 95% CI=1.28-1.42). The risk increased significantly for both colorectal cancer (RR=1.37, 95% CI=1.30-1.45) and adenoma (RR=1.26, 95% CI=1.11-1.44). Subgroup analyses on study design, gender, geographical region, and type of diabetes mellitus further evidenced these findings.

CONCLUSIONS

Diabetes mellitus was associated with an increased risk of colorectal neoplasia. Not only the increased risk of colorectal cancer but also the higher risk of adenoma was identified in patients with diabetes mellitus.

Metformin: A candidate for the treatment of gynecological tumors based on drug repositioning

Metformin is a first-line drug used for the treatment of type 2 diabetes. Recently, metformin has been reported to reduce the carcinogenic risk and inhibit tumor cell growth in glioma and breast cancer. The anticancer action of metformin involves the enhancement of phosphorylation of liver kinase B1, activation of adenosine monophosphate-activated protein kinase and inhibition of mammalian target of rapamycin, which reduces cell growth. Metformin is anticipated to exert antitumor effects in gynecological cancer, and its efficacy for the treatment of endometrial, breast and ovarian cancer has been suggested in preclinical studies and clinical trials. Although the effect of metformin on cervical cancer remains to be examined in clinical trials, its antitumor effects have been reported in preclinical studies. Thus, the use of metformin for the treatment of gynecological cancer may become a successful example of drug repositioning, following establishment of the drug's antitumor effects, risk evaluation, screening and validation of efficacy.

Impaired fasting glucose, single-nucleotide polymorphisms, and risk for colorectal cancer in Koreans

OBJECTIVES:

Numerous studies have demonstrated that fasting serum glucose (FSG) levels and certain single-nucleotide polymorphisms (SNPs) are related to an increased risk of colorectal cancer (CRC); however, their combined effects are still unclear.

METHODS:

Of a total of 144,527 men and women free of cancer at baseline, 317 developed CRC during 5.3 years of follow-up. A case-cohort study (n=1,691) was used, consisting of participants with a DNA sample available. Three well-known SNPs (rs3802842, rs6983267, rs10795668) were genotyped. Hazard ratios (HR) and 95% confidence intervals (CI) of CRC, colon and rectal cancer were calculated, with the Cox proportional hazard models.

RESULTS:

The crude incidence rates per 100,000 person-years were 41.1 overall, 48.4 for men, and 29.3 for women. Among participants with dysglycemia, SNPs rs3802842 and rs6983267 were both associated with an increased risk of CRC (HR, 3.2; 95% CI, 1.9 to 5.5 and HR, 1.8; 95% CI, 1.1 to 3.1, respectively) and rectal cancer (HR, 3.4; 95% CI, 1.8 to 6.6 and HR, 3.3; 95% CI, 1.6 to 7.1, respectively). The interaction effect of dysglycemia and SNPs was positive, that is, resulted in an elevated risk of CRC, but was not statistically significant.

CONCLUSIONS:

This study demonstrates that both high FSG and certain SNPs are major risk factors for CRC and rectal cancer but that they did not interact synergistically. The difference in effect size of the SNPs according to CRC subtype (i.e., colon or rectal cancer) and presence of dysglycemia merits further research.

Use of an α-Glucosidase Inhibitor and the Risk of Colorectal Cancer in Patients With Diabetes: A Nationwide, Population-Based Cohort Study

OBJECTIVE

Acarbose, an α-glucosidase inhibitor, has been shown to have antineoplastic effects on colorectal cancer in biomarker studies. We assessed the association between acarbose use in patients with diabetes and incident colorectal cancer.

RESEARCH DESIGN AND METHODS

We conducted a nationwide, population-based study using a large cohort with diabetes in the Taiwan National Health Insurance Research Database. Patients with newly diagnosed diabetes (n = 1,343,484) were enrolled between 1998 and 2010. One control subject not using acarbose was randomly selected for each subject using acarbose after matching for age, sex, diabetes onset, and comorbidities. Cox proportional hazards regression with a competing risks analysis was used to calculate the hazard ratios (HRs) and 95% CIs for the association between acarbose use and incident colorectal cancer for each eligible case-control pair (n = 199,296).

RESULTS

There were 1,332 incident cases of colorectal cancer in the cohort with diabetes during the follow-up period of 1,487,136 person-years. The overall incidence rate was 89.6 cases per 100,000 person-years. Patients treated with acarbose had a 27% reduction in the risk of colorectal cancer compared with control subjects. The adjusted HRs were 0.73 (95% CI 0.63-0.83), 0.69 (0.59-0.82), and 0.46 (0.37-0.58) for patients using >0 to <90, 90 to 364, and ≥365 cumulative defined daily doses of acarbose, respectively, compared with subjects who did not use acarbose (P for trend < 0.001).

CONCLUSIONS

Acarbose use reduced the risk of incident colorectal cancer in patients with diabetes in a dose-dependent manner.

Type 2 diabetes mellitus and colorectal neoplasia risk in Hispanics: a case-control study

AIMS

There is inconclusive evidence regarding the potential link between diabetes mellitus (DM) and colorectal cancer (CRC). Associations between type 2 DM and colorectal neoplasia (CRN; colorectal cancer and/or adenomas) have not been well studied in Hispanics, an ethnic minority at high risk for type 2 DM. This study aims to assess the association between type 2 DM and CRN in Hispanics.

METHODS

Hispanics with incident CRN and colonoscopy-negative controls from 2005 to 2009 were evaluated. Diagnosis of type 2 DM was established by previous medical diagnosis and/or use of DM treatments. Unconditional logistic regression was performed to estimate odds ratios for the association between type 2 DM and CRN.

RESULTS

A total of 451 participants (mean age 61.1±11.9years, 59.6 % men) were evaluated (218 with incident CRC, 77 with colorectal adenomas, and 156 colonoscopy-negative controls). The prevalence of type 2 DM in this study was 25.1%. After adjusting for potential confounding variables, women with type 2 DM were 2.74 (95% CI: 0.94-7.99) times more likely to have CRN and 4.83 times more likely to present with proximal colonic CRN (95% CI: 1.25-18.58) than women without type 2 DM. No statistically significant associations were found between type 2 DM and CRN among men.

CONCLUSIONS

An increased odds for CRN and proximal location of CRN was observed among Hispanic women with type 2 DM. Since DM is a highly prevalent disease in this population, adherence to routine CRC screening is of outmost importance.

Role of breast cancer inhibitors on diabetes mellitus- an in silico approach

Background

Breast cancer and diabetes mellitus type-2 are two of the major diseases, which cause death to the women worldwide. Around 16% of the breast cancer patients also suffer from diabetes mellitus. It has been noted that the risk of occurrence of the breast cancer is more in patients suffering from diabetes mellitus.

Methods

Owing to this, the present article deals with an objective of using the breast cancer inhibitors for the diabetes drug target– 1ADS. Ten breast cancer inhibitors were drawn using Marvin Sketch. The docking was performed using Molegro software (Molegro Virtual Docker, MVD).

Results

The docking wizard generated 50 poses with the highest Mol Dock score −131.649.

Conclusion

This investigation successfully evaluated the effect of breast cancer inhibitors on diabetes mellitus, providing a new dimension in endocrine research.

Interplay between 3'-UTR polymorphisms in the vascular endothelial growth factor (VEGF) gene and metabolic syndrome in determining the risk of colorectal cancer in Koreans

Background

Polymorphisms in angiogenesis-related genes and metabolic syndrome (MetS) risk factors play important roles in cancer development. Moreover, recent studies have reported associations between a number of 3′-UTR polymorphisms and a variety of cancers. The aim of this study was to investigate the associations of three VEGF 3′-UTR polymorphisms (1451C > T [rs3025040], 1612G > A [rs10434], and 1725G > A [rs3025053]) and MetS with colorectal cancer (CRC) susceptibility in Koreans.

Methods

A total of 850 participants (450 CRC patients and 400 controls) were enrolled in the study. The genotyping of VEGF polymorphisms was performed by TaqMan allelic discrimination assays. Cancer risks of genetic variations and gene-environment interactions were assessed by adjusted odds ratios (AORs) and 95% confidence intervals (CIs) of multivariate logistic regression analyses.

Results

VEGF 1451C > T was significantly associated with rectal cancer risk (Dominant model; AOR =1.58; 95% CI = 1.09 - 2.28; p = 0.015) whereas VEGF 1725G > A correlated with MetS risk (Dominant model; AOR =1.61; 95% CI =1.06 - 2.46; p = 0.026). Of the gene-environment combined effects, the interaction of VEGF 1451C > T and MetS contributed to increased rectal cancer risk (AOR = 3.15; 95% CI = 1.74 - 5.70; p < .001) whereas the combination of VEGF 1725G > A and MetS was involved with elevated colon cancer risk (AOR = 2.68; 95% CI = 1.30 - 1.55; p =0.008).

Conclusions

Our results implicate that VEGF 1451C > T and 1725G > A may predispose to CRC susceptibility and the genetic contributions may be varied with the presence of MetS.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-881) contains supplementary material, which is available to authorized users.

Diabetes and cancer: epidemiology and potential mechanisms

Type 2 diabetes mellitus is an independent risk factor for cancer such as pancreatic, liver, colorectal and breast cancer. In addition, diabetes decreases the risk of prostate cancer. These associations have been found in numerous epidemiological studies, among them several prospective cohorts. However, such studies do not prove causality of the association and cannot exclude inadequate correction for known confounders (e.g. visceral fat) or the influence of unknown confounders. Thus, it is unclear whether the cancer risk is increased by the causes (e.g. the metabolic syndrome), the metabolic consequences (e.g. hyperglycaemia) or the therapy of diabetes; a question which is of major importance for therapeutic guidelines. Identification of the potential mechanisms by which the diabetes or its therapy accelerates or inhibits the development of cancer will help answering the question by providing biological plausibility. This review will summarize the evidence supporting the association of cancer and type 2 diabetes and discuss its potential causes.

Association between fasting serum glucose levels and incidence of colorectal cancer in Korean men: the Korean Cancer Prevention Study-II

INTRODUCTION

The incidence of colorectal cancer (CRC) is steadily increasing worldwide. Numerous studies have demonstrated that diabetes mellitus is related to an increased risk of CRC; however, the association between impaired fasting glucose and CRC is unclear. Therefore, we evaluated the correlation between fasting serum glucose (FSG) levels and the incidence of CRC, which can be used to develop novel methods for preventing CRC.

METHODS

A total of 175,677 individuals from the Korean Metabolic Syndrome Research Initiative study were enrolled between 2004 and 2011. The incidence of CRC was assessed during a mean follow-up of 4.7 years. Hazard ratios (HR) for CRC according to FSG levels were calculated with the Cox proportional hazard model adjusted for age, sex, body mass index, smoking status, alcohol consumption, and regular exercise.

RESULTS

The risk of developing CRC in subjects with high FSG was significant (HR, 1.45; 95% confidence interval [CI], 1.10-1.90), and the risk was higher in men (HR, 1.51; 95% CI, 1.12-2.05). The HR of rectal cancer, but not colon cancer, was significantly higher both in the total population and in men in the high FSG group.

CONCLUSIONS

The incidence of CRC positively correlated with FSG levels in men. Rectal cancer incidence was especially correlated with high FSG in the site-specific analysis. Therefore, serum glucose levels maybe a potential marker of colorectal cancer. Early detection and intervention for controlling elevated glucose levels may be indicated as a way to prevent carcinogenesis.

Diabetes mellitus: influences on cancer risk

Diabetes mellitus and cancer are common conditions, and their co-diagnosis in the same individual is not infrequent. The relative risks associated with type 2 diabetes are greater than twofold for hepatic, pancreatic, and endometrial cancers. The relative risk is somewhat lower, at 1.2-1.5-fold for colorectal, breast, and bladder cancers. In comparison, the relative risk of lung cancer is less than 1. The evidence for other malignancies (e.g. kidney, non-Hodgkin lymphoma) is inconclusive, whereas prostatic cancer occurs less frequently in male patients with diabetes. The potential biologic links between the two diseases are incompletely understood. Evidence from observational studies suggests that some medications used to treat hyperglycemia are associated with either increased or reduced risk of cancer. Whereas anti-diabetic drugs have a minor influence on cancer risk, drugs used to treat cancer may either cause diabetes or worsen pre-existing diabetes. If hyperinsulinemia acts as a critical link between the observed increased cancer risk and type 2 diabetes, one would predict that patients with type 1 diabetes would have a different cancer risk pattern than patients with type 2 diabetes because the former patients are exposed to lower levels of exogenous administered insulin. Obtained results showed that patients with type 1 diabetes had elevated risks of cancers of the stomach, cervix, and endometrium. Type 1 diabetes is associated with a modest excess cancer risk overall and risks of specific cancers that differ from those associated with type 2 diabetes.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Role of metformin in suppressing 1,2-dimethylhydrazine-induced colon cancer in diabetic and non-diabetic mice: effect on tumor angiogenesis and cell proliferation

Several studies indicated that type 2 diabetes mellitus and insulin resistance are associated with increased colon cancer risk. Recently, studies suggest that metformin can reduce cancer risk in diabetic or non-diabetic patients with unclear mechanisms. This work aimed to determine the effect of metformin on chemically-induced colon cancer in mice. Colon cancer was induced using 1,2-dimethylhydrazine (DMH, 20 mg/kg/week, s.c.) for fifteen weeks. Experiment I: healthy mice were fed with basal diet for four weeks and then allocated into seven groups, (i) saline, (ii) DMH, (iii) oxaliplatin, (iv-v): metformin (100 or 200 mg/kg) and (vi-vii): oxaliplatin+metformin (100 or 200 mg/kg), respectively. Experiment II: type 2 diabetes mellitus was induced by injection of STZ (30 mg/kg) after four weeks of high-fat feeding and then mice were allocated into seven groups similar to those reported in experiment I. Examination of the colonic tissue at the end of the experiment highlighted an increase in angiogenic markers and cell proliferation and showed a greater immunostaining for insulin growth factor I receptors and CD34 in the colon of diabetic mice compared to non-diabetics. In general, metformin downregulated tumor angiogenesis and augmented the antitumor effect of oxaliplatin. Overall, the current results showed that metformin protected against DMH-induced colon cancer in non-diabetic and diabetic mice. This therapeutic effect was, at least in part, attributed to its anti-angiogenic and anti-proliferative mechanisms.

Association of serum hemoglobin A1c, C-peptide and insulin-like growth factor-1 levels with the occurrence and development of lung cancer

The present study aimed to investigate the correlation of the of hemoglobin A1c (HbA1c), C-peptide and insulin-like growth factor-1 (IGF-1) levels with the development and progression of lung cancer. The serum HbA1c, C-peptide and IGF-1 levels were measured and compared between 80 lung cancer patients and 80 healthy controls; furthermore, their correlation with histopathological type and tumor stage was analyzed in the 80 lung cancer patients. Our results suggested that the levels of HbA1c, C-peptide and IGF-1 were significantly increased in patients with lung cancer compared to those in the control group (P<0.05). In addition, the levels of C-peptide and IGF-1 were significantly higher in the small-cell lung cancer group (n=18), the stage III-IV (n=55) group and the lung cancer with diabetes mellitus group (n=43) compared to those in the non-small-cell lung cancer group (n=62), the stage I-II lung cancer group (n=25) and the lung cancer without diabetes group (n=37), respectively (P<0.05). Thus, the present study suggests that the increased serum HbA1c, C-peptide and IGF-1 levels are significantly correlated with the development and progression of lung cancer.

Diabetes and prognosis in older persons with colorectal cancer

BACKGROUND

Epidemiological studies have reported that diabetes significantly increases overall mortality in patients with colorectal cancer. However, it is unclear whether diabetes increases colorectal cancer-specific mortality. We used the US Surveillance Epidemiology and End Results (SEER) database linked with Medicare claims data to assess the influence of pre-existing diabetes on prognosis of patients with colorectal cancer.

METHODS

Data from 61,213 patients aged 67 or older with colorectal cancer diagnosed between 2003 and 2009 were extracted and prospectively followed through the date of death or the end of 2012 if the patient was still alive. Diabetes cases with and without complications were identified based on an algorithm developed for the Chronic Condition Data Warehouse (CCW). Cox models were used to estimate hazard ratios (HRs) for total mortality. The proportional subdistribution hazards model proposed by Fine and Gray was used to estimate HRs for colorectal cancer-specific mortality.

RESULTS

Compared with patients without diabetes, colorectal cancer patients with pre-existing diabetes had significantly higher risk of overall mortality (HR=1.20, 95 % confidence interval (95% CI): 1.17-1.23). The HR for overall mortality was more pronounced for patients who had diabetes with complications (HR=1.50, 95% CI: 1.42-1.58). However, diabetes was not associated with increased colorectal cancer-specific mortality after accounting for non-colorectal cancer outcomes as competing risk.

CONCLUSIONS

Pre-existing diabetes increased risk of total mortality among patients with colorectal cancer, especially among cancer patients who had diabetes with complications. The increased risk of total mortality associated with diabetes was primarily explained by increased cardiovascular-specific mortality, not by increased colorectal cancer-specific mortality.

Management of colorectal cancer and diabetes

Colorectal cancer is associated with diabetes mellitus and both of these common conditions are often managed together by a surgeon. The surgical focus is usually upon cancer treatment rather than diabetes management. The relationship between colorectal cancer and diabetes is a complex one and can raise problems in both diagnosis and the management of patients with both conditions. This literature review explores the relationship between diabetes, diabetic treatment and colorectal cancer and addresses the issues that arise in diagnosing and treating this patient group. By highlighting these difficulties, this review aims to improve understanding and to provide clearer insight into both surgical and non-surgical management.

Metabolic dysregulation of the insulin-glucose axis and risk of obesity-related cancers in the Framingham heart study-offspring cohort (1971-2008)

BACKGROUND

Obesity-related dysregulation of the insulin-glucose axis is hypothesized in carcinogenesis. We studied impaired fasting glucose (IFG) and other markers of insulin-glucose metabolism in the Framingham Heart Study-Offspring Cohort, which uniquely tracks these markers and cancer >37 years.

METHODS

Participants were recruited between 1971 and 1975 and followed until 2008 (n = 4,615; mean age 66.8 years in 2008). Serum glucose, insulin, and hemoglobin A1c were determined from fasting blood in quart-annual exams. Lifestyle and demographic information was self-reported. HRs and 95% confidence intervals (CI) of cancer risk were computed using time-dependent survival analysis (SASv9.3), while accounting for temporal changes for relevant variables.

RESULTS

We identified 787 obesity-related cancers, including 136 colorectal, 217 breast, and 219 prostate cancers. Absence versus presence of IFG 10 to 20 years and 20+ years before the event or last follow-up was associated with 44% (95% CI, 1.15-1.79) and 57% (95% CI, 1.17-2.11) increased risk of obesity-related cancers, respectively. When time-dependent variables were used, after adjusting for age, sex, smoking, alcohol, and body mass index, IFG was associated with a 27% increased risk of obesity-related cancer (HR = 1.27; CI, 1.1-1.5). Associations were stronger in smokers (HR = 1.41; CI, 1.13-1.76). Increased risk was noted among persons with higher insulin (HR = 1.47; CI, 1.15-1.88) and hemoglobin A1c (HR = 1.54; CI, 1.13-2.10) for the highest (≥ 5.73%) versus lowest (≤ 5.25%) category. A >2-fold increase in colorectal cancer risk was observed for all blood biomarkers of insulin-glucose metabolism, particularly with earlier IFG exposure. Nonsignificant increased risk of breast and prostate cancer was observed for blood biomarkers.

CONCLUSIONS

Earlier IFG exposure (>10 years before) increased obesity-related cancer risk, particularly for colorectal cancer.

IMPACT

Our study explicitly recognizes the importance of prolonged IFG exposure in identifying links between glucose dysregulation and obesity-related cancers.