Prospective study of colorectal cancer risk and physical activity, diabetes, blood glucose and BMI: exploring the hyperinsulinaemia hypothesis

Diabetes mellitus and the occurrence of colorectal cancer: an updated meta-analysis of cohort studies

BACKGROUND

Recently, it has been found that diabetes patients have a higher incidence of colorectal cancer than the general population, but epidemiological studies examining a potential relationship between the two have produced inconsistent conclusions. Thus, we set out to perform a meta-analysis of cohort studies to evaluate the association between diabetes and colorectal cancer.

MATERIALS AND METHODS

Using "diabetes," "colorectal cancer," and associated key words, we performed a systematic review of published cohort studies in multiple databases, including MEDLINE, EMBASE, ISI Web of Knowledge databases, OVID, CNKI, CBMD ISC, WANFANG, and CQVIP. We then applied stringent inclusion and exclusion criteria to identify which studies to include in our analysis. STATA version 12.0 software (StataCorp., College Station, TX) was used to conduct statistical analysis, including consolidated statistics calculations, tests for heterogeneity, and publication bias evaluations.

RESULTS

We obtained a total of 532 potential articles. In accordance with our inclusion and exclusion criteria, we selected 29 articles for the meta-analysis. The analysis of extracted information indicated that diabetes is a risk factor for the development of colorectal cancer (relative risk 1.22, 95% confidence interval 1.19-1.26). Subgroup analyses by control populations, regions, gender, follow-up time, and colorectal cancer site also support this finding.

CONCLUSIONS

The risk of individuals with diabetes to develop colorectal cancer is 1.22 times higher than that of individuals without diabetes. The positive association remains consistent for both men and women and for studies carried out in North America, Europe, and Asia, as well as for different follow-up times.

Meta-analyses of colorectal cancer risk factors

PURPOSE

Demographic, behavioral, and environmental factors have been associated with increased risk of colorectal cancer (CRC). We reviewed the published evidence and explored associations between risk factors and CRC incidence.

METHODS

We identified 12 established non-screening CRC risk factors and performed a comprehensive review and meta-analyses to quantify each factor's impact on CRC risk. We used random-effects models of the logarithms of risks across studies: inverse-variance weighted averages for dichotomous factors and generalized least squares for dose-response for multi-level factors.

RESULTS

Significant risk factors include inflammatory bowel disease (RR = 2.93, 95 % CI 1.79-4.81); CRC history in first-degree relative (RR = 1.80, 95 % CI 1.61-2.02); body mass index (BMI) to overall population (RR = 1.10 per 8 kg/m(2) increase, 95 % CI 1.08-1.12); physical activity (RR = 0.88, 95 % CI 0.86-0.91 for 2 standard deviations increased physical activity score); cigarette smoking (RR = 1.06, 95 % CI 1.03-1.08 for 5 pack-years); and consumption of red meat (RR = 1.13, 95 % CI 1.09-1.16 for 5 servings/week), fruit (RR = 0.85, 95 % CI 0.75-0.96 for 3 servings/day), and vegetables (RR = 0.86, 95 % CI 0.78-0.94 for 5 servings/day).

CONCLUSIONS

We developed a comprehensive risk modeling strategy that incorporates multiple effects to predict an individual's risk of developing CRC. Inflammatory bowel disease and history of CRC in first-degree relatives are associated with much higher risk of CRC. Increased BMI, red meat intake, cigarette smoking, low physical activity, low vegetable consumption, and low fruit consumption were associated with moderately increased risk of CRC.

Diabetes and sex-specific colorectal cancer risks in Newfoundland and Labrador: a population-based retrospective cohort study

OBJECTIVE

Studies on the relationship between diabetes and colorectal cancer (CRC) are inconsistent. It is also unclear whether CRC risk elevation for individuals with diabetes is similar for males and females. Using data from Newfoundland and Labrador (NL), the province with the highest CRC incidence and diabetes prevalence in Canada, we assessed and compared the risk elevation of CRC for males and females with diabetes, overall and by anatomic subsite.

METHODS

A population-based retrospective cohort study including a study sample of 122,228 individuals aged ≥30 years was conducted using administrative health databases over a 10.5-year period (October 1, 1996 to March 31, 2007). Hazard ratios were estimated using Cox proportional hazard models.

RESULTS

In comparison with non-diabetes counterparts, both males and females with diabetes were at a significantly elevated risk of overall CRC, with corresponding hazard ratios of 1.38 and 1.52, respectively. For males, diabetes significantly increased the risk of proximal and distal colon cancers, but not of rectal cancer. For females, diabetes significantly increased the risk of proximal colon and rectal cancers, but not of distal colon cancer. The results suggest that there is a stronger association between diabetes and CRC for females than for males, and the association did not change after adjusting for overweight/obesity.

CONCLUSIONS

Diabetes led to a greater risk of CRC in both the male and female population in NL. Risk was subsite-specific and varied by sex. Future research should examine reasons for the observed diabetes-associated CRC risk to support CRC prevention strategies among the diabetes population.

Two Valid Measures of Self-rated Physical Activity and Capacity

Objectives:

Questionnaires on physical activity (PA) and physical capacity (PC) are valuable tools, as they are cost beneficial, and have high response rates. The validity of short versions of such questionnaires has not been examined satisfactorily. Therefore, we aimed at examining the validity of a set of questions coding for PA and PC.

Design:

The questions were administered to 217 men and women attending a cardiac rehabilitation program. Participants also gave blood samples, measuring HDL cholesterol, triglycerides (TG), insulin, glucose, and microCRP. The relations between PA and PC and biological markers were examined by linear regression analyses.

Results:

Measures for PC and for PA were identified by factor analysis, which proved internally consistent. TG, homeostatic model assessment (HOMA) score, and mCRP were all significantly associated with the measures of PC and PA.

Conclusions:

The measures of PA and PC are valid compared with biological markers, allowing cost-beneficial and time-efficient evaluation of important measures for cardiovascular health.

Racial disparities in colorectal cancer incidence by type 2 diabetes mellitus status

PURPOSE

Type 2 diabetes mellitus (T2DM) prevalence has increased dramatically in the United States since the early 1970s. Though T2DM is known to be associated with colorectal cancer (CRC), information on racial differences in the relationship between T2DM and CRC is limited.

METHODS

Using a retrospective cohort design, we compared the association between T2DM and CRC, including subsites of the colon, in African Americans (AAs) and European Americans (EAs) in South Carolina, a region with large racial disparities in rates of both diseases. A total of 91,836 individuals who were ≥30 years old on 1 January 1990 and had ≥12 months of South Carolina Medicaid eligibility between 1 January 1990 and 31 December 1995 were included in the analyses. Cancer data from 1996 to 2007 included information on anatomic subsite.

RESULTS

Subjects who had T2DM (n = 6,006) were >50 % more likely to be diagnosed with colon cancer compared to those without T2DM (n = 85,681). The association between T2DM and colon cancer was higher in AAs [odds ratio (OR) = 1.72 (95 % confidence interval: 1.21, 2.46); n = 47,984] than among EAs (OR = 1.24; 0.73, 2.11; n = 43,703). Overall, individuals with T2DM were over twice as likely to be diagnosed with in situ or local colon cancer (OR = 2.12; 1.40, 3.22; n = 191) compared to those without T2DM, with a higher likelihood among AAs (OR = 2.49; 1.52, 4.09; n = 113).

CONCLUSIONS

Results from a Medicaid population in a high-risk region of the United States showed an increased likelihood of CRC with T2DM and suggest a racial disparity that disfavors AAs and provides further impetus for efforts aimed at diabetes prevention in this group.

Diabetes mellitus and the incidence and mortality of colorectal cancer: a meta-analysis of 24 cohort studies

AIM

The incidence and mortality of colorectal cancer (CRC) were quantified in persons with and without diabetes mellitus (DM).

METHOD

Medline and Embase were searched for articles published before July 2010. Cohort studies that evaluated incidence and mortality of DM and CRC were included. The initial search identified 1887 titles, of which 24 articles met the inclusion criteria. We defined the relative risk (RR) as the metric of choice; 95% confidence intervals (CIs) were calculated with a random-effects model.

RESULTS

There was an increase in the RR of developing CRC in persons with DM compared with those without DM (RR 1.28; 95% CI 1.19-1.39), without heterogeneity between studies (P(heterogeneity) = 0.13). The association between duration of DM and CRC incidence was stronger in the 11-15-year group (RR 1.51; 95% CI 1.12-2.03) than in the <10-year group (RR 1.05; 95% CI 0.90-1.22) and the >15-year group (RR 1.25; 95% CI 0.80-1.94), and there was significant heterogeneity among subgroups (P(heterogeneity) = 0.01). In studies reporting standardized incidence ratios (SIRs), there was an increased incidence of CRC with DM (RR 1.27; 95% CI 1.14-1.42; P(heterogeneity) = 0.09), and the association was stronger among men (RR 1.47; 95% CI 1.15-1.86) than women (RR 1.08; 95% CI 1.00-1.17); there was significant heterogeneity among gender (P(heterogeneity) = 0.01).

CONCLUSION

This meta-analysis suggests that individuals with DM have a significant increase in risk of developing CRC.

Criteria for Patient Selection and Multidisciplinary Evaluation and Treatment of the Weight Loss Surgery Patient

OBJECTIVE

To provide evidence-based guidelines for patient selection and to recommend the medical and nutritional aspects of multidisciplinary care required to minimize perioperative and postoperative risks in patients with severe obesity who undergo weight loss surgery (WLS).

RESEARCH METHODS AND PROCEDURES

Members of the Multidisciplinary Care Task Group conducted searches of MEDLINE and PubMed for articles related to WLS in general and medical and nutritional care in particular. Pertinent abstracts and literature were reviewed for references. Multiple searches were carried out for various aspects of multidisciplinary care published between 1980 and 2004. A total of 3000 abstracts were identified; 242 were reviewed in detail.

RESULTS

We recommended multidisciplinary screening of WLS patients to ensure appropriate selection; preoperative assessment for cardiovascular, pulmonary, gastrointestinal, endocrine, and other obesity-related diseases associated with increased risk for complications or mortality; preoperative weight loss and cessation of smoking; perioperative prophylaxis for deep vein thrombosis and pulmonary embolism (PE); preoperative and postoperative education and counseling by a registered dietitian; and a well-defined postsurgical diet progression.

DISCUSSION

Obesity-related diseases are often undiagnosed before WLS, putting patients at increased risk for complications and/or early mortality. Multidisciplinary assessment and care to minimize short- and long-term risks include: comprehensive medical screening; appropriate pre-, peri-, and postoperative preparation; collaboration with multiple patient care disciplines (e.g., anesthesiology, pulmonary medicine, cardiology, and psychology); and long-term nutrition education/counseling.

MONW phenotype is associated with advanced colorectal adenoma in Korean men

The aim of this study was to investigate whether there was a relationship between colorectal adenoma and metabolically obese but normal weight (MONW) among Korean men and women. The MONW phenotype is defined as a BMI <25, but fulfilling the metabolic syndrome (MS) criteria with a modified waist circumference (≥90 cm for men and ≥85 cm for women) appropriate for Korean. A total of 3,430 subjects (2,263 men and 1,167 women; 23-75 years old) were included in the study. Colorectal adenomas were diagnosed in 775 men and 199 women. The rate of advanced adenomas in males was 24.3% and in females 21.1%. A significant association between MONW and advanced colorectal adenoma was found in men (age-adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI): 1.06-3.47) but not in women (age-adjusted OR = 1.80, 95% CI: 0.50-6.45). The findings suggest that men with MONW may have an increased risk of developing advanced colorectal adenoma whereas this does not seem true for females.

Diabetes but not insulin is associated with higher colon cancer mortality

AIM: To evaluate whether diabetic patients had a higher risk of colon cancer mortality and its associated risk factors.

METHODS: The sex-specific crude and age-standardized (to the 2000 World Health Organization population) mortality rates of colon cancer in the Taiwanese general population were first calculated from 1995 to 2006. The trends were evaluated by linear regression. A total of 113 347 diabetic men and 131 573 diabetic women aged ≥ 25 years at recruitment from 1995 to 1998 were followed up until the end of 2006. Age/sex-specific colon cancer mortality rate ratios were calculated comparing the mortality rates of the diabetic patients with the average mortality rates of the general population within 12 years (1995-2006). A sub-cohort of diabetic patients (42 260 men and 49 405 women) was interviewed using a baseline questionnaire and Cox’s regression was used to evaluate the risk factors for colon cancer mortality in these diabetic patients.

RESULTS: The crude and age-standardized trends of colon cancer mortality from 1995 to 2006 increased significantly for both sexes in the general population. A total of 641 diabetic men and 573 diabetic women died of colon cancer, with a mortality rate of 74.4 and 54.3 per 100 000 person-years, respectively. Mortality rate ratios [95% confidence intervals (CIs)] showed a significantly higher risk of mortality from colon cancer for the diabetic patients compared to the general population, with the magnitude increasing with decreasing age: 1.65 (1.40-1.95), 2.01 (1.78-2.27), 2.75 (2.36-3.21) and 5.69 (4.65-6.96) for ≥ 75, 65-74, 55-64 and 25-54 years old, respectively, for men; and 1.46 (1.24-1.72), 2.09 (1.84-2.38), 2.67 (2.27-3.14) and 3.05 (2.29-4.06), respectively, for women. Among the sub-cohort of diabetic patients who had been interviewed with the baseline questionnaire, including information on age, sex, diabetes duration, diabetes type, body mass index, smoking, insulin use and area of residence, age and smoking were significantly predictive for colon cancer mortality, with respective adjusted hazard ratios (HRs) (95% CIs) of 1.077 (1.066-1.088) and 1.384 (1.068-1.792). Diabetes duration became a significant factor when those who died of colon cancer within 5 years of diabetes diagnosis were excluded to minimize the possible contamination of diabetes caused by incipient colon cancer, with an adjusted hazard ratio of 1.021 (1.007-1.034). Sex, diabetes type, insulin use, body mass index and area of residence were not significant predictors for colon cancer mortality in the diabetic patients. Although insulin use was categorized into subgroups of duration of use (non-users and users < 5 years, 5-9 years and ≥ 10 years), none of the HRs for colon cancer mortality was significant with regards to different durations of insulin use.

CONCLUSION: Colon cancer mortality is increasing in Taiwan. A higher risk is observed in diabetic patients. Smoking, but not insulin use, is a modifiable risk factor.

Age- and sex-specific risks of colorectal cancers in diabetic patients

Diabetes has been reported to increase the risk of colorectal neoplasm in most but not all studies. However, the data on age- and sex-specific incidence rates and relative risks associated with diabetes are limited. We carried out this population-based cohort study to investigate the overall sex- and age-specific risks of colorectal cancer in association with diabetes. Diabetic patients (n = 615,532) and age- and sex-matched control individuals (n = 614,871), selected from the claim datasets, were followed up from 2000 to 2006. The rates of admission due to colon and rectum cancers were estimated using the person-years approach, and the age- and sex-specific hazard ratio (HR) for both the malignancies were determined using the Cox regression model. The overall incidence rate of colon cancer was 9.94 per 10,000 patient-years for the diabetic patients, as opposed to 7.84 per 10,000 patient-years for the control-group patients. The corresponding observation for rectal cancer was 7.16 and 6.28 per 10,000 patient-years. Diabetic patients aged ≥ 45 years had significantly high HRs for developing colon cancer (1.20-1.45-fold). We also noted a significantly high HR of rectal cancer in diabetic men (1.18-fold) aged ≥ 45 years, but not in diabetic women. In conclusion, diabetes may significantly increase the risk of colorectal cancer, especially in patients aged 45-64 years. Diabetologists should keep this relationship in mind while treating middle-aged diabetic men and should also advise these patients to undergo regular screening tests for colorectal cancer.

Fasting glucose and treatment outcome in breast and colorectal cancer patients treated with targeted agents: results from a historic cohort

BACKGROUND

We investigated pretreatment fasting glucose as a predictor of patients' important outcomes in breast and colorectal cancers undergoing targeted therapies.

PATIENTS AND METHODS

In a historic cohort of 202 breast and 218 colorectal cancers treated with targeted agents from 1998 to 2009, we used the Kaplan-Meier method and the log-rank test to estimate survival through tertiles of fasting glucose and the Cox proportional hazards model for multivariate analysis stratified by primary site of cancer and including gender, age and body mass index.

RESULTS

The median follow-up was 20 months (1-128). At 60 months, 65% of patients in the lowest tertile of fasting glucose did not experiment disease progression compared with 34% in the highest tertile (P=0.001). Seventy-six percent of females in the lowest tertile showed no progression compared with 49% in the top tertiles (P=0.015). In multivariate analysis, fasting glucose was a significant predictor of time to disease progression only in breast cancer patients in the first tertile compared with the third (P=0.017).

CONCLUSIONS

We found evidence of a predictive role of pretreatment fasting glucose in the development of resistance in breast cancer patients treated with targeted agents. Prospective studies are warranted to confirm our findings.

A longitudinal study of the metabolic syndrome and risk of colorectal cancer in postmenopausal women

The metabolic syndrome is associated with increased risk of diabetes and coronary heart disease. Although higher BMI and other related factors have been frequently associated with colorectal cancer, whether the metabolic syndrome is associated with the risk of colorectal cancer is unclear. We therefore assessed the association of the metabolic syndrome with the risk of colorectal cancer in a subsample of participants of the Women's Health Initiative who had repeated measurements of the components of the syndrome at baseline and during follow-up. Women with diabetes at baseline enrollment were excluded. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CI) at baseline and in time-dependent analyses. Among 4862 eligible women, 81 incident cases of colorectal cancer were identified over a median follow-up of 12 years. Presence of the metabolic syndrome at baseline was associated with increased risk of colorectal cancer (HR 2.15, 95% CI 1.30-3.53) and colon cancer (HR 2.28, 95% CI 1.31-3.98). These associations were largely explained by positive associations of serum glucose and systolic blood pressure with both outcomes. Time-dependent covariate analyses supported the baseline findings. Our results suggest that the positive association of the metabolic syndrome with risk of colorectal cancer is largely accounted for by serum glucose levels and systolic blood pressure. The biological mechanism underlying these associations remains to be clarified.

Differential impact of structurally different anti-diabetic drugs on proliferation and chemosensitivity of acute lymphoblastic leukemia cells

Hyperglycemia during hyper-CVAD chemotherapy is associated with poor outcomes of acute lymphoblastic leukemia (ALL) (Cancer 2004; 100: 1179-85). The optimal clinical strategy to manage hyperglycemia during hyper-CVAD is unclear. To examine whether anti-diabetic pharmacotherapy can influence chemosensitivity of ALL cells, we examined the impacts of different anti-diabetic agents on ALL cell lines and patient samples. Pharmacologically achievable concentrations of insulin, aspart and glargine significantly increased the number of ALL cells, and aspart and glargine did so at lower concentrations than human insulin. In contrast, metformin and rosiglitazone significantly decreased the cell number. Human insulin and analogs activated AKT/mTOR signaling and stimulated ALL cell proliferation (as measured by flow cytometric methods), but metformin and rosiglitazone blocked AKT/mTOR signaling and inhibited proliferation. Metformin 500 μM and rosiglitazone 10 μM were found to sensitize Reh cells to daunorubicin, while aspart, glargine and human insulin (all at 1.25 mIU/L) enhanced chemoresistance. Metformin and rosiglitazone enhanced daunorubicin-induced apoptosis, while insulin, aspart and glargine antagonized daunorubicin-induced apoptosis. In addition, metformin increased etoposide-induced and L-asparaginase-induced apoptosis; rosiglitazone increased etoposide-induced and vincristine-induced apoptosis. In conclusion, our results suggest that use of insulins to control hyperglycemia in ALL patients may contribute to anthracycline chemoresistance, while metformin and thiazolidinediones may improve chemosensitivity to anthracycline as well as other chemotherapy drugs through their different impacts on AKT/mTOR signaling in leukemic cells. Our data suggest that the choice of anti-diabetic pharmacotherapy during chemotherapy may influence clinical outcomes in ALL.

Diabetes mellitus and the incidence of colorectal cancer: an updated systematic review and meta-analysis

AIM

The purpose of this study was to determine whether diabetes mellitus is associated with an increased risk of colorectal cancer.

METHODS

Relevant studies were identified in MEDLINE and EMBASE (up until November 1st, 2011). Inclusion criteria were original, peer-reviewed publications, with case-control and cohort studies (for studies on diabetes mellitus and colorectal cancer). Summary relative risks with 95% confidence intervals were calculated with a random-effects model.

RESULTS

Twenty-four studies including eight case-control and 16 cohort studies, with a total of 3,659,341 participants, were included in this updated systematic review and meta-analysis, and all involved diabetes mellitus and colorectal cancer risk. Meta-analysis of the 24 included studies indicated that diabetes was associated with an increased risk of colorectal cancer, compared with no diabetes (summary RR of colorectal cancer incidence = 1.26, 95% CI = 1.20-1.31), without heterogeneity between studies (P(heterogeneity) = 0.296). Sub-group analyses found that these results were consistent between case-control and cohort studies and among studies conducted in different areas. The association between diabetes and colorectal cancer incidence did not differ significantly by sex and sub-sites. Insulin therapy was also positively associated with risk of colorectal cancer (summary RR = 1.61, 95% CI 1.18-1.35), with evidence of heterogeneity between studies (P(heterogeneity) = 0.014).

CONCLUSIONS

Our findings further support a relationship between diabetes and increased risk of colon and rectal cancer in both women and men, and insulin therapy for diabetes may increase this risk.

A randomized controlled trial of an intensive insulin regimen in patients with hyperglycemic acute lymphoblastic leukemia

Hyperglycemia during hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with methotrexate and high-dose cytarabine, with methylprednisolone premedication) chemotherapy is associated with poor outcomes of acute lymphoblastic leukemia (ALL). To examine whether intensive insulin therapy could improve outcomes, a randomized trial was conducted that compared glargine plus aspart vs. conventional therapy. Intensive insulin did not improve ALL clinical outcomes despite improved glycemic control. Secondary analysis suggests that the choice of antidiabetic pharmacotherapy may influence ALL outcomes.

INTRODUCTION

Hyperglycemia during hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with methotrexate and high-dose cytarabine, with methylprednisolone premedication) chemotherapy is associated with poor outcomes of acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

To examine whether an intensive insulin regimen could improve outcomes compared with conventional antidiabetic pharmacotherapy, a randomized trial was conducted that compared glargine plus aspart vs. conventional therapy (control). Between April 2004 and July 2008, 52 patients newly diagnosed with ALL, Burkitt lymphoma, or lymphoblastic lymphoma who were on hyper-CVAD in the inpatient setting and had a random serum glucose level >180 mg/dL on ≥2 occasions during chemotherapy were enrolled.

RESULTS

The trial was terminated early due to futility regarding ALL clinical outcomes despite improved glycemic control. Secondary analysis revealed that molar insulin-to-C-peptide ratio (I/C) > 0.175 (a surrogate measure of exogenous insulin usage) was associated with decreased overall survival, complete remission duration and progression-free survival (PFS), whereas metformin and/or thiazolidinedione usage were associated with increased PFS. In multivariate analyses, factors that significantly predicted short overall survival included age ≥ 60 years (P = .0002), I/C ≥ 0.175 (P = .0016), and average glucose level ≥ 180 mg/dL (P = .0236). Factors that significantly predicted short PFS included age ≥ 60 years (P = .0008), I/C ≥ 0.175 (P = .0002), high systemic risk (P = .0173) and average glucose level ≥ 180 mg/dL (P = .0249). I/C ≥ 0.175 was the only significant (P = .0042) factor that predicted short complete remission duration.

CONCLUSIONS

A glargine-plus-aspart intensive insulin regimen did not improve ALL outcomes in patients with hyperglycemia. Exogenous insulin may be associated with poor outcomes, whereas metformin and thiazolidinediones may be associated with improved outcomes. Analysis of these results suggests that the choice of antidiabetic pharmacotherapy may influence ALL outcomes.

Diabetes mellitus is an independent risk factor for colorectal cancer

BACKGROUND

Epidemiological studies have suggested positive associations between diabetes and colorectal cancer. However, the findings were inconsistent, especially regarding specific sex or cancer subsite.

AIMS

To conduct a systematic review with meta-analysis to examine the association of diabetes mellitus with risk of colorectal cancer and to investigate whether the association is dependent on sex, cancer subsite, race/ethnicity, or duration of diabetes.

METHODS

Relevant studies were identified by searching Pubmed to May 12, 2011. The reference lists of identified articles were also reviewed. Two authors independently selected the studies and extracted relevant data. The study quality was assessed.

RESULTS

Thirty-nine studies (28 cohort studies and 11 case-control studies) were included in the final analysis. Compared with non-diabetic subjects, the pooled risk estimate of colorectal cancer for diabetic subjects was 1.29 (95% CI = 1.23-1.35). The subgroup analyses revealed that the risk was significantly increased for both genders, for every cancer subsite, and for both short duration and long duration of diabetes. Exposure to diabetes increased the risk of colorectal cancer for White and Asian, whereas there was no evidence of such an association either among Black or native Hawaiians.

CONCLUSIONS

Our results confirmed that subjects with diabetes are at modestly increased risk of developing colorectal cancer.

Hyperhomocysteinemia is a risk factor for colorectal adenoma in women

Homocysteine is involved in a one-carbon transfer reaction, which is important for DNA synthesis and methylation. High level of plasma homocysteine, biochemical marker of folate status, is known to be a risk factor for cancer. However, it is inconclusive as to whether plasma homocysteine concentration can predict colorectal adenoma. We conducted a case-control study to determine whether hyperhomocysteinemia is a risk factor for adenoma. Data from 1,039 subjects who underwent a colonoscopy and plasma homocysteine concentration determination during health examinations at single center over a two-year period were analyzed. The subjects were classified into two groups (422 adenoma and 617 controls). Subjects defined as having advanced adenomas were those with more than three adenomas, over 1 cm in size, high grade dysplasia, or villous components. Male, old age, high body mass index, low high-density lipoprotein-cholesterol, smoking, fasting glucose, and past history of colon polyps were significantly associated with adenoma according to multiple logistic regression. According to subgroup analysis by gender, plasma homocysteine concentration was not associated with adenoma in males; however, a high plasma homocysteine concentration significantly increased the risk of adenoma as well as advanced adenoma in females. Hyperhomocysteinemia is a risk factor for colorectal adenoma in women.

Type 2 diabetes mellitus and gender-specific risk for colorectal neoplasia

Although a positive association between type 2 diabetes mellitus (T2DM) and colorectal cancer is well established, uncertainty exists about risk differences in diabetic men and women when considering colorectal neoplasia (CN). The main objective was to examine gender-specific associations of T2DM with CN in a population-based cohort study of adults in Germany. This analysis is based on participants of the ESTHER-study, a population-based cohort study. Participants were 50-74 years old at baseline and underwent colonoscopy during 5 year follow-up. CN detected at colonoscopy were validated by medical records review. Total and gender-specific associations of T2DM at baseline and CN were estimated using log-binomial regression. Overall, 55 cases of CN were detected in 166 participants with T2DM and 328 cases in 1,360 participants without T2DM. In women, CN was found in 32 % of participants with T2DM and in 18 % without T2DM (adjusted prevalence ratio (PR): 1.66 95 % CI 1.04-2.64). In men, prevalence for CN was 35 % for those with T2DM and 33 % for those without T2DM (adjusted PR = 1.01; 95 % CI 0.71-1.43). T2DM might have a stronger impact on CN among women than among men. Further research should examine possible reasons for these differences.

History of diabetes and risk of head and neck cancer: a pooled analysis from the international head and neck cancer epidemiology consortium

BACKGROUND

A history of diabetes is associated with an increased risk of several types of cancers. Whether diabetes is a risk factor for head and neck cancer (HNC) has received little attention.

METHODS

We pooled data from 12 case-control studies including 6,448 cases and 13,747 controls, and estimated OR and 95% CI for the associations between diabetes and HNC, adjusted for age, education level, sex, race/ethnicity, study center, cigarette smoking, alcohol use, and body mass index.

RESULTS

We observed a weak association between diabetes and the incidence of HNC overall (OR, 1.09; 95% CI: 0.95-1.24). However, we observed a modest association among never smokers (OR, 1.59; 95% CI: 1.22-2.07), and no association among ever smokers (OR, 0.96; 95% CI: 0.83-1.11); likelihood ratio test for interaction P = 0.001.

CONCLUSION

A history of diabetes was weakly associated with HNC overall, but we observed evidence of effect modification by smoking status, with a positive association among those who never smoked cigarettes.

IMPACT

This study suggests that glucose metabolism abnormalities may be a HNC risk factor in subgroups of the population. Prospective studies incorporating biomarkers are needed to improve our understanding of the relationship between diabetes and HNC risk, possibly providing new strategies in the prevention of HNC.

Cryptogenic pyogenic liver abscess as the herald of colon cancer

BACKGROUND AND AIM

Colonic mucosal defects might be a route for bacterial invasion into the portal system, with subsequent hematogenous spread to the liver. We retrospectively investigated the results of colonoscopy and the clinical characteristics of patients with pyogenic liver abscess of colonic origin.

METHODS

A total of 230 consecutive patients with pyogenic liver abscess were reviewed between 2003 and 2010. The 230 patients were categorized into three groups (pancreatobiliary [n = 135], cryptogenic [n = 81], and others [n = 14]). Of the 81 cryptogenic patients, 37 (45.7%) underwent colonoscopy. Colonic lesions with mucosal defects were considered colonic causes of abscess.

RESULTS

In the 37 colonoscopic investigations, colon cancer was found in six patients (16.2%), laterally-spreading tumor (LST) in two patients (5.4%), multiple colon ulcers in one patient (2.7%), colon polyps in 17 patients (45.9%), and diverticula in four patients (10.8%). Nine (11%) of 81 cryptogenic abscesses were therefore reclassified as being of colonic origin (colon cancer = 6, LST = 2, ulcer = 1). Three cases were stage III colon cancer, and the others were stage I. Two LST were high-grade dysplasia. The percentage of patients with Klebsiella pneumoniae (K. pneumoniae) and diabetes mellitus (DM) of colonic origin was 66.7%, which was significantly higher than the 8.6% for other causes (P < 0.001).

CONCLUSIONS

Of the 37 patients with cryptogenic pyogenic liver abscess who underwent colonoscopy, nine (24.3%) were diagnosed with a colonic cause. Colonoscopy should be considered for the detection of hidden colonic malignant lesions in patients with cryptogenic pyogenic liver abscess, especially for patients with K. pneumoniae and DM.

Calcium and vitamin D and risk of colorectal cancer: results from a large population-based case-control study in Newfoundland and Labrador and Ontario

BACKGROUND

Previous epidemiological studies have been suggestive but inconclusive in demonstrating inverse associations of calcium, vitamin D, dairy product intakes with risk of colorectal cancer (CRC). We conducted a large population-based comparison of such associations in Newfoundland and Labrador (NL) and Ontario (ON).

METHODS

A case control study design was used. Colorectal cancer cases were new CRC patients aged 20-74 years. Controls were a sex and age-group matched random sample of the population in each province. 1760 cases and 2481 controls from NL and ON were analyzed. Information on dietary intake and lifestyle was collected using self-administered food frequency and personal history questionnaires.

RESULTS

Controls reported higher mean daily intakes of total calcium and total vitamin D than cases in both provinces. In ON, significant reduced CRC risk was associated with intakes of total calcium (OR of highest vs. lowest quintiles was 0.57, 95% CI 0.42-0.77, p(trend) = 0.03), total vitamin D (OR = 0.73, 95% CI 0.54-1.00), dietary calcium (OR = 0.76, 95% CI 0.60-0.97), dietary vitamin D (OR = 0.77, 95% CI 0.61-0.99), total dairy products and milk (OR = 0.78, 95% CI 0.60-1.00), calcium-containing supplements use (OR = 0.76). In NL, the inverse associations of calcium, vitamin D with CRC risk were most pronounced among calcium- or vitamin D-containing supplement users (OR = 0.67, 0.68, respectively).

CONCLUSIONS

Results of this study add to the evidence that total calcium, dietary calcium, total vitamin D, dietary vitamin D, calcium- or vitamin D-containing supplement use may reduce the risk of CRC. The inverse associations of CRC risk with intakes of total dairy products and milk may be largely due to calcium and vitamin D.

Monosodium glutamate-induced diabetic mice are susceptible to azoxymethane-induced colon tumorigenesis

Obese people and diabetic patients are known to be high risk of colorectal cancer (CRC), suggesting need of a new preclinical animal model, by which to extensively study the diverse mechanisms, therapy and prevention. The present study aimed to determine whether experimental obese and diabetic mice produced by monosodium glutamate (MSG) treatment are susceptible to azoxymethane (AOM)-induced colon tumorigenesis using early biomarkers, aberrant crypts foci (ACF) and β-catenin-accumulated crypts (BCACs), of colorectal carcinogenesis. Male Crj:CD-1 (ICR) newborns were daily given four subcutaneous injections of MSG (2 mg/g body wt) to induce diabetes and obesity. They were then given four intraperitoneal injections of AOM (15 mg/kg body wt) or saline (0.1 ml saline/10 g body wt). Ten weeks after the last injection of AOM, the MSG-AOM mice had a significant increase in the multiplicity of BCAC (13.83 ± 7.44, P < 0.002), but not ACF (78.00 ± 11.20), when compare to the Saline-AOM mice (5.45 ± 1.86 of BCAC and 69.27 ± 8.06 of ACF). Serum biochemical profile of the MSG-treated mice with or without AOM showed hyperinsulinemia, hypercholesteremia and hyperglycemia. The mRNA expression of insulin-like growth factor-1 receptor (IGF-1R, P<0.01) was increased in the MSG-AOM mice, when compared with the mice given AOM alone. IGF-1R was immunohistochemically expressed in the BCAC, but not ACF, in the AOM-treated mice. Our findings suggest that the MSG mice are highly susceptible to AOM-induced colorectal carcinogenesis, suggesting potential utility of our MSG-AOM mice for further investigation of the possible underlying events that affect the positive association between obese/diabetes and CRC.

Diabetes and the risk for colorectal cancer

Diabetes mellitus has been reported to be associated with an increased risk for colorectal cancer. The review analyzes current epidemiological data on the association of diabetes and the risk for colorectal cancer. Hyperinsulinemia, hyperglycemia, and inflammation are suggested to play a key role in the pathophysiology of cancer in diabetes. Data regarding potential treatment-related risks, particularly in conjunction with the use of insulin and insulin analogues, are also presented. Furthermore, the impact of glycemic control and cardiorespiratory fitness on cancer prognosis is considered. Finally, the preventive potential of aspirin and other nonsteroidal anti-inflammatory drugs, and the recommendations concerning colonoscopy-screening are presented.

Diabetes Mellitus and Colorectal Neoplasia

BACKGROUND

Many studies have provided evidence for an association between obesity, physical inactivity, and western diet as risk factors for colorectal cancer (CRC). Few studies directly address the association between type 2 Diabetes Mellitus (DM) and the risk of colorectal lesions at specific anatomic locations.

METHODS

2,663 subjects with a previous history of adenoma(s) and removal of all current adenomas at study entry were followed for a mean time of three years across three different chemoprevention clinical trials. The primary endpoint was colorectal adenoma recurrence and number of lesions during the treatment phase; the secondary endpoints were presence of advanced colorectal neoplasia (CRN) and location of CRN. Using log linear regression, the effect of DM status on the relative risk (RR) of CRN recurrence, advanced CRN, and location of CRN was assessed.

RESULTS

DM status was not significantly associated with incidence of colorectal adenomas, incidence of advanced colorectal lesions, or left-sided colorectal neoplastic lesions. Subjects with DM had a marginally increased risk of right-sided (p= 0.06) colorectal adenomas and a significant increased risk of multiple right-sided adenomas (p=0.03) in the unadjusted model; this association was not significant after adjusting for age and other potential confounders (RR=1.22, 95% CI: 0.85-1.76).

CONCLUSION

We did not observe a statistically significant increased risk in CRN recurrence for overall neoplasia, advanced neoplasia or location of neoplasia in individuals with DM compared to non-DM individuals. However, given the patterns observed in this investigation, future studies with longer follow-up time and longer DM exposure, incorporating objective measurements of type 2 DM might help elucidate the risk of CRN among individuals with DM.

Type 2 diabetes risk variants and colorectal cancer risk: the Multiethnic Cohort and PAGE studies

BACKGROUND

Diabetes has been positively associated with the risk of colorectal cancer. This study investigated whether recently established risk variants for diabetes also have effects on colorectal cancer.

METHODS

19 single nucleotide repeats (SNPs) associated with type 2 diabetes in genome-wide association studies were tested in a case-control study of 2011 colorectal cancer cases and 6049 controls nested in the Multiethnic Cohort study as part of the Population Architecture using Genomics and Epidemiology (PAGE) initiative. ORs and 95% CIs were estimated by unconditional logistic regression to evaluate the association between SNPs and colorectal cancer risk, adjusting for age, sex and race/ethnicity. Permutation testing was conducted to correct for multiple hypothesis testing.

RESULTS

Four type 2 diabetes SNPs were associated with colorectal cancer risk: rs7578597 (THADA), rs864745 (JAZF1), rs5219 (KCNJ11) and rs7961581 (TSPAN8, LGR5). The strongest association was for the rs7578597 (THADA) Thr1187Ala missense polymorphism (P(trend)=0.004 adjusted for multiple testing), with the high risk allele for colorectal cancer being the low risk allele for diabetes. Similar patterns of associations were seen with further adjustment for diabetes status and body mass index. The association of diabetes status with colorectal cancer risk was somewhat weakened after adjustment for these SNPs.

CONCLUSION

The findings suggest that diabetes risk variants also influence colorectal cancer susceptibility, possibly through mechanisms different from those for diabetes.

Glycated hemoglobin A1c is superior to fasting plasma glucose as an independent risk factor for colorectal neoplasia

OBJECTIVE

To investigate which glycemic index is more strongly associated with colorectal neoplasia.

METHOD

This cross-sectional study enrolled 2,776 participants in a comprehensive health management program which included measurement of fasting plasma glucose and HbA1c, along with screening colonoscopy. Primary outcome was colorectal adenoma with or without dysplasia. Risk factors for colorectal neoplasia were determined by the multivariate regression analysis, which evaluated the interrelationship among different glycemic indices in a hierarchical way.

RESULTS

Colorectal neoplasms were found in 605 (21.79%) examinees, 68 (2.45%) of whom had high-risk tumors. Glycemic indices including diagnosis of diabetes mellitus, fasting plasma glucose, and HbA1c were all associated with colorectal tumors in the univariate analysis. However, HbA1c outperformed the other two markers as an independent risk factor (adjusted odds ratio, 1.22; 95% confidence interval, 1.10-1.36%) for colorectal neoplasia. Moreover, only HbA1c remained independently associated with colorectal tumor after patients with established diagnosis of diabetes (n = 132) were excluded. We also identified age, male gender, and smoking were independent risk factors for colorectal neoplasia.

CONCLUSION

HbA1c as compared with fasting plasma glucose is more strongly and independently associated with colorectal neoplasia. Further research is warranted to elucidate the value of HbA1c in stratifying risk of colorectal cancer.

A longitudinal study of serum insulin and glucose levels in relation to colorectal cancer risk among postmenopausal women

Background:

It is unclear whether circulating insulin or glucose levels are associated with increased risk of colorectal cancer. Few prospective studies have examined this question, and only one study had repeated measurements.

Methods:

We conducted a prospective study of colorectal cancer risk using the subsample of women in the Women's Health Initiative study whose fasting blood samples, collected at baseline and during follow-up, were analysed for insulin and glucose. Cox proportional hazards models were used to assess associations with colorectal cancer risk in both baseline and time-dependent covariates analyses.

Results:

Among 4902 non-diabetic women with baseline fasting serum insulin and glucose values, 81 incident cases of colorectal cancer were identified over 12 years of follow-up. Baseline glucose levels were positively associated with colorectal cancer and colon cancer risk: multivariable-adjusted hazard ratio (HR) comparing the highest (⩾99.5 mg dl⁻¹) with the lowest tertile (<89.5 mg dl⁻¹): 1.74, 95% confidence interval (CI) 0.97–3.15 and 2.25, 95% CI: 1.12–4.51, respectively. Serum insulin and homeostasis model assessment were not associated with risk. Analyses of repeated measurements supported the baseline results.

Conclusion:

These data suggest that elevated serum glucose levels may be a risk factor for colorectal cancer in postmenopausal women.

Metformin and thiazolidinediones are associated with improved breast cancer-specific survival of diabetic women with HER2+ breast cancer

BACKGROUND

Insulin/insulin-like growth factor-I (IGF-I) signaling is a mechanism mediating the promoting effect of type 2 diabetes (DM2) on cancer. Human epidermal growth factor receptor (HER2), insulin receptor and IGF-I receptor involve the same PI3K/AKT/mTOR signaling, and different antidiabetic pharmacotherapy may differentially affect this pathway, leading to different prognoses of HER2+ breast cancer.

METHODS

We reviewed 1983 consecutive patients with HER2+ breast cancer treated between 1 January 1998 and 30 September 2010. The overall survival, breast cancer-specific death rate, age, race, nuclear grade, stage, menopausal status, estrogen and progesterone receptor status, body mass index and classes of antidiabetic pharmacotherapy were analyzed.

RESULTS

A Cox regression analysis showed that DM2 [P=0.026, hazard ratio (HR)=1.42, 95 % confidence interval (95 % CI) 1.04-1.94] predicted poor survival of stage≥2 HER2+ breast cancer. In Kaplan-Meier analysis, metformin predicted lengthened survival and so did thiazolidinediones. Analyzing only the diabetics, Cox regression showed that metformin (P=0.041, HR=0.52, 95 % CI 0.28-0.97) and thiazolidinediones (P=0.036; HR=0.41, 95% CI 0.18-0.93) predicted lengthened survival, and competing risk analysis showed that metformin and thiazolidinediones were associated with decreased breast cancer-specific mortality (P=0.023, HR=0.47, 95% CI 0.24-0.90 and P=0.044, HR=0.42, 95 % CI 0.18-0.98, respectively).

CONCLUSIONS

Thiazolidinediones and metformin users are associated with better clinical outcomes than nonusers in diabetics with stage≥2 HER2+ breast cancer. The choice of antidiabetic pharmacotherapy may influence prognosis of this group.

POTENTIAL MECHANISMS OF CANCER PREVENTION BY WEIGHT CONTROL

Weight control via dietary caloric restriction and/or physical activity has been demonstrated in animal models for cancer prevention. However, the underlying mechanisms are not fully understood. Body weight loss due to negative energy balance significantly reduces some metabolic growth factors and endocrinal hormones such as IGF-1, leptin, and adiponectin, but enhances glucocorticoids, that may be associated with anti-cancer mechanisms. In this review, we summarized the recent studies related to weight control and growth factors. The potential molecular targets focused on those growth factors- and hormones-dependent cellular signaling pathways are further discussed. It appears that multiple factors and multiple signaling cascades, especially for Ras-MAPK-proliferation and PI3K-Akt-anti-apoptosis, could be involved in response to weight change by dietary calorie restriction and/or exercise training. Considering prevalence of obesity or overweight that becomes apparent over the world, understanding the underlying mechanisms among weight control, endocrine change and cancer risk is critically important. Future studies using "-omics" technologies will be warrant for a broader and deeper mechanistic information regarding cancer prevention by weight control.

Colorectal cancer screening among primary care patients: does risk affect screening behavior?

Lifestyle factors including smoking, obesity, and diabetes can increase colorectal cancer (CRC) risk. Controversy exists regarding screening rates in individuals at increased CRC risk. To examine the effect of risk on CRC screening in primary care, cross-sectional data collected during January 2006-July 2007 from 720 participants in 24 New Jersey primary care practices were analyzed. Participants were stratified by risk: high (personal/family history of CRC, history of polyps, inflammatory bowel disease), increased (obesity, Type II diabetes, current/former smokers), and average. Outcomes were up-to-date with CRC screening, receiving a physician recommendation for screening, and recommendation adherence. Chi-square and generalized linear modeling were used to determine the effect of independent variables on risk group and risk group on outcomes. Thirty-seven percent of participants were high-risk, 46% increased-risk, and 17% average-risk. Age, race, insurance, education, and health status were related to risk. High-risk participants had increased odds of being up-to-date with screening (OR 3.14 95% CI 1.85-5.32) and adhering to physician recommendation (OR 7.18 95% CI 3.58-14.4) compared to average-risk. Increased-risk participants had 32% decreased odds of screening (OR 0.68, 95% CI 0.42-1.08). Low screening rates among increased-risk individuals highlight the need for screening interventions targeting these patients.

Is diabetes mellitus an independent risk factor for colon cancer and rectal cancer?

OBJECTIVES

Diabetes mellitus (DM) has been associated with an increased risk of colorectal cancer (CRC). The American College of Gastroenterology Guidelines for Colorectal Cancer Screening 2008 recommend that clinicians be aware of an increased CRC risk in patients with smoking and obesity, but do not highlight the increase in CRC risk in patients with DM. To provide an updated quantitative assessment of the association of DM with colon cancer (CC) and rectal cancer (RC), we conducted a meta-analysis of case-control and cohort studies. We also evaluated whether the association varied by sex, and assessed potential confounders including obesity, smoking, and exercise.

METHODS

We identified studies by searching the EMBASE and MEDLINE databases (from inception through 31 December 2009) and by searching bibliographies of relevant articles. Summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with fixed- and random-effects models. Several subgroup analyses were performed to explore potential study heterogeneity and bias.

RESULTS

DM was associated with an increased risk of CC (summary RR 1.38, 95% CI 1.26-1.51; n=14 studies) and RC (summary RR 1.20, 95% CI 1.09-1.31; n=12 studies). The association remained when we limited the meta-analysis to studies that either controlled for smoking and obesity, or for smoking, obesity, and physical exercise. DM was associated with an increased risk of CC for both men (summary RR 1.43, 95% CI 1.30-1.57; n=11 studies) and women (summary RR 1.35, 95% CI 1.14-1.53; n=10 studies). For RC, there was a significant association between DM and cancer risk for men (summary RR 1.22, 95% CI 1.07-1.40; n=8 studies), but not for women (summary RR 1.09, 95% CI=0.99-1.19; n=8 studies).

CONCLUSIONS

These data suggest that DM is an independent risk factor for colon and rectal cancer. Although these findings are based on observational epidemiological studies that have inherent limitations due to diagnostic bias and confounding, subgroup analyses confirmed the consistency of our findings across study type and population. This information can inform risk models and specialty society CRC screening guidelines.

Diabetes mellitus and incidence and mortality of colorectal cancer: a systematic review and meta-analysis of cohort studies

Increasing evidence suggests that a history of diabetes mellitus (DM) may be associated with an increased risk of colorectal cancer (CRC). To provide a quantitative assessment of the association between DM and risk of CRC, We evaluated the relation between DM and incidence and mortality of CRC in a systematic review of cohort studies. Full publications of cohort studies were identified in MEDLINE, EMBASE and Science Citation Index Expanded, through February 28, 2011. Summary relative risks (SRRs) with 95% confidence intervals (CIs) were summarized using a random-effects model. Between-study heterogeneity was assessed using the Cochran's Q and I2 statistics. A total of 41 cohort studies (35 articles) were included in this systematic review. Combining 30 cohort studies which presented results on diabetes and CRC incidence, diabetes was associated with an increased incidence of CRC (SRRs 1.27, 95% CI: 1.21-1.34), with evident heterogeneity among studies (P=0.002, I2=48.4%). Subgroup analysis and meta-regression analysis by controlling the confounders showed that the increased incidence of CRC was independent of geographic locations, sex, family history of colorectal cancer, smoking, physical activity and body mass index. Diabetes was also positively associated with CRC mortality (SRR 1.20, 95% CI: 1.03-1.40), with evidence of heterogeneity between studies (P<0.001, I2=81.4%). Results from this systematic review support that compared to non-diabetic individuals, diabetic individuals have an increased risk of CRC.

Metabolic syndrome is associated with increased risk of recurrent colorectal adenomas in Korean men

OBJECTIVE

Because of the high incidence of recurrent colorectal adenomas, regular surveillance by colonoscopy is recommended. However, there is still a shortage of information on the factors that influence the incidence of recurrent colorectal adenomas in patients with a history of these lesions. The aim of this study was to determine the association between the development of recurrent colorectal adenomas, metabolic syndrome and obesity.

SUBJECTS AND METHODS

The hospital-based cohort was composed of 193 patients who had recurrent colorectal adenomas removed between January 2002 and December 2003. The Cox proportional hazard model was used to determine hazard ratio (HR) and 95% confidence interval (CI) between obesity, metabolic syndrome and other factors, and the incidence of recurrent adenomatous polyps.

RESULTS

The mean follow-up period was 4.8 person-years. In all, 78 of the patients (40.4%) had recurrent colorectal adenomas. In the overall recurrent adenoma group, significant associations between metabolic syndrome (HR, 1.33; 95% CI, 1.02-1.73), waist circumference (WC) ≥ 90 cm (HR, 1.42; 95% CI, 1.06-1.90) and waist-hip ratio (WHR) ≥ 0.9 (HR, 2.03; 95% CI, 1.55-2.68) were found. Moreover, advanced adenomas were significantly associated with metabolic syndrome (HR, 2.81; 95% CI, 1.86-4.25), body mass index ≥ 25 kg m(-2) (HR, 2.69; 95% CI, 1.64-4.42), WC (HR, 2.16; 95% CI, 1.31-3.54) and WHR (HR, 1.99; 95% CI, 1.28-3.11). In addition, current smoking (HR, 2.60; 95% CI, 1.09-6.25) and alcohol consumption (HR, 2.20; 95% CI, 1.10-4.39) were also significantly associated with recurrent advanced adenoma.

CONCLUSION

Metabolic syndrome and obesity were significantly associated with the development of recurrent colorectal adenomas in Korean adult males. Furthermore, these associations were more strongly associated with advanced adenomas.

Type 2 diabetes mellitus and colorectal cancer: meta-analysis on sex-specific differences

Although there is consent concerning a higher risk for colorectal cancer (CRC) amongst patients with type 2 diabetes mellitus (T2DM), there remains uncertainty regarding potential sex differences in the strength of this association. We reviewed and summarised epidemiological studies assessing the sex-specific association of T2DM with the risk for CRC. All relevant studies published until 14th February 2011 were identified by a systematic search of MEDLINE, EMBASE, BIOSIS Previews and ISI Web of Knowledge databases and cross-referencing. We included observational studies that reported relative risk (RR) or odds ratio (OR) estimates with 95% confidence intervals (CIs) for the association between T2DM and CRC. Two authors independently extracted data and assessed study quality of each study in a standardised manner. Study-specific estimates were pooled for both sexes separately using random-effects models. A total of 29 eligible studies were used for meta-analysis. Overall estimates of relative risk (RR) were very similar amongst men (RR=1.29; 95%-confidence interval (CI): 1.19-1.140) and women (RR=1.34; 95%-CI: 1.22-1.47). In both men and women, risk estimates from case-control studies were slightly higher than those from cohort studies. Overall, T2DM is associated with a moderate increase in CRC risk in both men and women.

The impact of type 2 diabetes and antidiabetic drugs on cancer cell growth

Despite investigations into mechanisms linking type 2 diabetes and cancer, there is a gap in knowledge about pharmacotherapy for diabetes in cancer patients. Epidemiological studies have shown that diabetic cancer patients on different antidiabetic treatments have different survival. The clinically relevant question is whether some antidiabetic pharmacotherapeutic agents promote cancer whereas others inhibit cancer progression. We investigated the hypothesis that various antidiabetic drugs had differential direct impact on cancer cells using four human cell lines (pancreatic cancer: MiaPaCa2, Panc-1; breast cancer: MCF7, HER18). We found that insulin and glucose promoted cancer cell proliferation and contributed to chemoresistance. Metformin and rosiglitazone suppressed cancer cell growth and induced apoptosis. Both drugs affected signalling in the protein kinases B (AKT)/mammalian target of rapamycin pathway; metformin activated adenosine monophosphate (AMP)-activated protein kinase whereas rosiglitazone increased chromosome ten level. Although high insulin and glucose concentrations promoted chemoresistance, the combination of metformin or rosiglitazone with gemcitabine or doxorubicin, resulted in an additional decrease in live cancer cells and increase in apoptosis. In contrast, exenatide did not have direct effect on cancer cells. In conclusion, different types of antidiabetic pharmacotherapy had a differential direct impact on cancer cells. This study provides experimental evidence to support further investigation of metformin and rosiglitazone as first-line therapies for type 2 diabetes in cancer patients.

Basal insulin treatment in type 2 diabetes

Insulin glargine is the first 24-h recombinant DNA insulin analog introduced to the market. Substitution of glycine for asparagine and addition of two arginine residues raise the isoelectric point of insulin glargine and result in microprecipitates, delaying absorption from subcutaneous tissue. This delayed absorption result in fairly flat 24-h insulin concentration profiles with no discernible peak. Large, multicenter, randomized, controlled trials in patients with type 2 diabetes show that although NPH insulin and insulin glargine are equally effective in lowering glycosylated hemoglobin (A1c) and fasting blood glucose, there is a clear advantage of insulin glargine over NPH insulin in reducing nocturnal and overall hypoglycemia. Lower risk of hypoglycemia with glargine was also consistently demonstrated by trials comparing insulin glargine and premixed analog insulins. These studies also showed greater reduction in A1c with twice-daily premixed insulins compared with glargine, when insulin glargine was administered without mealtime insulin coverage. Insulin glargine was also compared with another insulin analog, insulin detemir. Trials showed that both insulin analogs are equally effective in lowering A1c and have comparable risk of hypoglycemia. Trials comparing insulin glargine with glucagon-like peptide-1 agonists showed comparable significant reductions in A1c with both regimens. Insulin glargine is well tolerated, has low immunogenicity, reduced risks for acute myocardial infarction, and a lower risk of hypoglycemia compared with NPH insulin in individuals with type 2 diabetes.

Cancer risk in type 2 diabetes mellitus: metabolic links and therapeutic considerations

Type 2 diabetes mellitus (DM2) is increasing in incidence, creating worldwide public health concerns and impacting morbidity and mortality rates. An increasing number of studies have demonstrated shared associations between DM2 and malignancy, including key clinical, biochemical, and metabolic commonalities. This paper will attempt to explore the relationship between the various types of cancer and diabetes, the common metabolic pathways underlying cancer development, and the potential impact of various antidiabetes therapies on cancer risk.

Thiazolidinediones and metformin associated with improved survival of diabetic prostate cancer patients

BACKGROUND

The association between antidiabetic medications and the prognosis of human prostate cancer has not been explored. This study examined the impact of these drugs on the outcomes of diabetic patients with prostate cancer to provide a basis for diabetes management strategy in these patients.

PATIENTS AND METHODS

Records of consecutive prostate cancer patients with coexisting diabetes mellitus type 2 who were treated at the study institution between 15 July 1999 and 31 December 2008 were reviewed. The survival, cancer pathological grade, stage at the time of diagnosis, and antidiabetic pharmacotherapy of the patients were analyzed.

RESULTS

A total of 233 consecutive cases were analyzed. In Kaplan-Meier analysis, thiazolidinedione (log-rank, P = 0.005) and metformin (log-rank, P = 0.035) usage were significant predictors of improved overall survival, while insulin and insulin secretagogue usage were not significant predictors. Multivariate Cox regression analysis showed that thiazolidinedione {hazard ratio [HR] = 0.454 [95% confidence interval (CI) 0.213-0.965], P = 0.040} and metformin [HR = 0.550 (95% CI 0.315-0.960), P = 0.035] usage remained as significant predictors of favorable survival after controlling for variables including age, race, Gleason grade, and stage.

CONCLUSIONS

Thiazolidinediones and metformin appear to be associated with improved overall survival of diabetic prostate cancer patients. The choice of antidiabetic pharmacotherapy may influence overall survival of these patients.

Risk of cancer in a large cohort of U.S. veterans with diabetes

Prior studies of cancer risk among diabetic men have reported inconsistent findings. The aim of this study was to assess the risk of cancer among a large cohort (n = 4,501,578) of black and white U.S. veterans admitted to Veterans Affairs hospitals. The cancer risk among men with diabetes (n = 594,815) was compared to the risk among men without diabetes (n = 3,906,763). Poisson regression was used to estimate adjusted relative risks (RRs) and 95% confidence intervals (CIs). Overall, men with diabetes had a significantly lower risk of cancer (RR = 0.93, 95%CI = 0.93-0.94). Men with diabetes, however, had increased risks of cancers of the liver (RR = 1.95, 95%CI = 1.82-2.09), pancreas (RR = 1.50, 95%CI = 1.42-1.59), biliary tract (RR = 1.41, 95%CI = 1.22-1.62), colon (RR = 1.20, 95%CI = 1.16-1.25), rectum (RR = 1.12, 95%CI = 1.07-1.18), and kidney (RR = 1.09, 95%CI = 1.03-1.16), as well as leukemia (RR = 1.14, 95%CI = 1.08-1.21) and melanoma (RR = 1.13, 95%CI = 1.03-1.24). In contrast, men with diabetes had decreased risks of cancers of the prostate (RR = 0.89, 95%CI = 0.87-0.91), brain (RR = 0.91, 95% CI = 0.82-0.99), buccal cavity (RR = 0.85, 95%CI = 0.82-0.89), lung (RR = 0.79, 95%CI = 0.77-0.80), esophagus (RR = 0.77, 95%CI = 0.72-0.82), and larynx (RR = 0.76, 95%CI = 0.71-0.80). These findings indicate that black and white men with diabetes are at significantly lower risk of total cancer and of two of the most common cancers among U.S. males; lung and prostate cancers. These decreased risks were offset, however, by increased risks of cancer at several sites. Hyperinsulinemia may explain the increased risks of the digestive cancers, while lower testosterone levels, in the case of prostate cancer, and higher BMI, in the case of lung cancer, may explain the decreased risks of those tumors.

[Antidiabetic therapy--a new possibility in the complex therapy of cancer?]

Nowadays the lack of exercise and improper eating habits are main characteristics of modern life style. This favors not only formation of type 2 diabetes or cardiovascular diseases, but also increaseas the incidence and prevalence of malignant tumors. Today there are many epidemiologic trials that demonstrate the connection between type 2 diabetes and formation of several malignomas. Its cause should be searched in common paths of pathologic processes. One of this is the birth of hyperinsulinsulinemia, which accompanies insulin resistance. Hyperinsulinemia of the host leads to increased glucose uptake in the highly insuline sensitive tumor cells which supports tumor growth. This makes type 2 diabetes a metabolic state favoring tumor formation, suggesting a potential application of oral insulin sensitizers in cancer therapy. Currently several international trials are testing the anti-tumor activity of metformin and thiazolidinedions (TZD). Besides this, encouraging results were obtained with the use of anti-IGFR antibodies in the treatment of tumors. A common therapy of diabetes and tumor may lead to new possibilities in the treatment of malignant tumor diseases. By doing this we could be able to weaken the tumor and strengthen the body, enabling it to fight against cancer. Bánhegyi RJ, Rus-Gal PO, Nagy AK, Martyin T, Varga R, Pikó B. Correlation between type 2 diabetes and malignant tumors - new possibilities in the complex therapy of cancers?

Prevalence and recurrence rate of colonic lesions in acromegalic patients

Acromegaly is associated with an increased prevalence of colonic polyps. The aim of this study was to evaluate the prevalence and recurrence rate of colonic polyps in acromegalic patients. Ninety-six acromegalic patients and 100 irritable bowel syndrome patients (IBS) were enrolled in the study. Twenty patients who were cured exclusively by surgery, and 20 patients that could not be hormonally controlled were re-examined colonoscopically after 36 months. Twenty-nine of 96 acromegalic patients (30.2%) had colonic polyps. In the IBS group, 10 (10.0%) had colonic polyps. The prevalence of colonic polyps was significantly higher in acromegaly. The group of acromegalic patients with and without polyps did not differ significantly with regard to plasma GH, IGF-I, fasting insulin levels and glycemic status. The presence of colonic polyps was correlated with increased patient age and male gender. We did not observe a difference in terms of polyp recurrence frequencies in the patients cured by surgery compared to uncontrolled patients. Acromegalic patients have a higher prevalence of colonic polyps than that of control subjects. We could not identify any factors that could predict polyps within the acromegalic patients - but age and male sex.

Increased pulse wave velocity reflecting arterial stiffness in patients with colorectal adenomas

The obese patients with diabetes or cardiovascular risk factors are associated with increased risk of colorectal cancer as well as adenomas under the shared pathogenesis related to atherosclerosis. Here we determined the association between increased arterial stiffness and colorectal adenomas incorporating parameters including age, gender, waist circumference, body mass index, lipid profiles, fasting glucose, and blood pressure. Subjects who simultaneously underwent colonoscopies and pulse wave velocity (PWV) determinations between July 2005 and September 2006 were analyzed, based on which the subjects were classified into two groups as patients group with colorectal adenomas (n = 49) and control group (n = 200) with normal, non-polypoid benign lesions or hyperplastic polyps. Uni- and multi-variate analyses were performed to calculate the odd ratio for colon adenomas. Based on uni-variate analysis, age, waist circumference, body mass index, heart-femoral PWV (hfPWV), and brachial-ankle PWV were significantly associated with adenomas (p<0.05) and multiple logistic regression analysis showed that the heart-femoral PWV, waist circumference, and the levels of LDL-C were significant risk factor for colorectal adenoma. However, arterial stiffness did not affect the progression of colon adenoma. The finding that hfPWV, reflecting aortic stiffness, was increased in patients with colorectal adenomas lead to conclusion that patients who have prominently increased arterial stiffness can be recommended to undergo colonoscopic examinations and at the same time we also recommend counseling about the risk for atherosclerosis in those who have colorectal adenomas.

Body mass index as a predictor of colorectal neoplasia in ethnically diverse screening population

BACKGROUND

Recent guidelines from the American College of Gastroenterology for screening for colorectal cancer have included obesity as an important risk factor. The recommendation for screening obese people at earlier age was tempered by the need for more data regarding obesity and colorectal neoplasia.

AIMS

We designed a cross-sectional study to further examine the predictive value of obesity for colorectal adenomas in asymptomatic patients.

METHODS

We prospectively collected demographic, medical, lifestyle, and dietary history from asymptomatic patients presenting for screening colonoscopy. Patients underwent complete colonoscopy using high-definition colonoscope to detect colorectal adenomas. We defined advanced neoplasia as large (≥ 1 cm) adenoma, villous adenoma, high-grade dysplasia or cancer.

RESULTS

Six hundred patients with median age of 56 years completed the study. Over 40% of these patients did not consider themselves Caucasian, and less than 5% had a first-degree relative with colorectal cancer. Overall, 40 patients (6.7%) had advanced neoplasia and 216 (36.3%) had any adenoma. There were 185 obese patients (30.8%), who had a prevalence of 44.3% for any adenoma and 13.0% for advanced neoplasia. After multivariate analysis, obesity [body mass index (BMI) ≥ 30 kg/m(2)] was significantly associated with increased risk of advanced neoplasia [odds ratio (OR) = 3.83; 95% confidence interval (CI): 1.94-7.55].

CONCLUSIONS

Obesity was associated with advanced neoplasia in this screening population. Our data regarding the association of colorectal neoplasia with this modifiable risk factor has implications for screening and prevention of colorectal cancer.

The impact of diabetes process and outcome quality measures on overall survival in patients with co-morbid colorectal cancer

PURPOSE

To evaluate the effect of prevalent diabetes mellitus (DM) and quality of diabetes process and outcome measures on overall survival in colorectal cancer (CRC) patients.

PATIENT AND METHODS

We conducted a retrospective cohort study among patients newly diagnosed with CRC. Kaplan-Meier analyses and Cox proportional hazard regression models were performed. Quality of diabetes process and outcomes measures in the year prior to CRC diagnosis were compared with those in the year after CRC diagnosis.

RESULTS

Four hundred and seventy CRC patients were identified during the study period, including 122 (26%) patients with DM. Survival between diabetic and non-diabetic were not significantly different after stratifying by stage. In a multivariable model, only age (HR 1.04), stage 2 and 3 (HR 1.88), stage 4 (HR 4.26), and Deyo comorbidity score (HR 1.14) were significantly associated with increased risk of death. Overall, patients in this CRC cohort with DM had good to excellent diabetes quality of care in the year prior to diagnosis as evidenced by primary care and eye clinic visits, number of times diabetes intermediate outcomes were measured, and level of cholesterol (95.5 ± 29.74) and hemoglobin A1c (7.2% + 1.4) control. After CRC diagnosis, there was no significant change in these quality of care indices compared to the year prior.

CONCLUSIONS

Prevalent DM did not affect overall survival in this cohort of VA patients diagnosed with CRC. The quality of diabetes care prior to CRC diagnosis, which persisted after diagnosis, may have moderated the mortality effect of diabetes in this CRC cohort.

Diabetes and risk of incident colorectal cancer in a prospective cohort of women

OBJECTIVE

To determine whether accounting for the time dynamics of diabetes exposure will change the risk estimates for colorectal cancer.

METHODS

We analyzed data from the 45, 516 women enrolled in the BCDDP follow-up cohort study. We used proportional hazards regression to obtain multivariable-adjusted risk estimates for incident colorectal cancer for prevalent diabetes at baseline and diabetes as a time-dependent variable.

RESULTS

Subjects with diabetes had a statistically significant increased risk of colorectal cancer compared to subjects without diabetes (RR = 1.60, 95% CI 1.18-2.18). When we defined exposure as duration of diabetes exposure at cohort exit, we found that in the first 4 years after diagnosis risk was essentially the same as in those never having had a diagnosis of diabetes. For those who had been diagnosed between 4 and 8 years previously, however, we observed a RR of 2.36 (95% CI 0.96-5.79), while longer duration of exposure was associated with smaller and then no change in risk compared to those without a diagnosis of diabetes.

CONCLUSIONS

These results are consistent with the theory that hyperinsulinemia can explain, at least in part, the association of diabetes with colorectal cancer, but in a time-dependent manner.

The association of diabetes with colorectal cancer risk: the Multiethnic Cohort

Background:

Diabetics have been found to have a greater risk of colorectal cancer than non-diabetics.

Methods:

We examined whether this relationship differed by ethnic group, cancer site or tumour stage in a population-based prospective cohort, including 3549 incident colorectal cancer cases identified over a 13-year period (1993–2006) among 199 143 European American, African American, Native Hawaiian, Japanese American and Latino men and women in the Multiethnic Cohort.

Results:

Diabetics overall had a significantly greater risk of colorectal cancer than did non-diabetics (relative risk (RR)=1.19, 95% confidence interval (CI)=1.09–1.29, P-value (P)<0.001). Positive associations were observed for colon cancer, cancers of both the right and left colon, and cancers diagnosed at a localised and regional/distant stage. The association with colorectal cancer risk was significantly modified by smoking status (P_Interaction=0.0044), with the RR being higher in never smokers (RR=1.32, 95% CI=1.15–1.53, P<0.001) than past (RR=1.19, 95% CI=1.05–1.34, P=0.007) and current smokers (RR=0.90, 95% CI=0.70–1.15, P=0.40).

Conclusion:

These findings provide strong support for the hypothesis that diabetes is a risk factor for colorectal cancer.

The Frequency and Risk Factors of Colorectal Adenoma in Health-Check-up Subjects in South Korea: Relationship to Abdominal Obesity and Age

BACKGROUND/AIMS

Obesity is associated with the risk of colorectal cancer. However, there is a lack of information about the relationship between obesity and colorectal adenoma. We investigated whether general and abdominal obesity are risk factors for colorectal adenoma.

METHODS

Subjects who received health check-ups, including colonoscopy, from April 2006 to September 2007 in Chung-Ang University Hospital were included (n=1,316). The frequency and characteristics of colorectal adenomas were analyzed according to demographic features, past history, blood tests, body mass index, and components of metabolic syndrome. Abdominal obesity was defined as a waist circumference of >/=80 cm in women and >/=90 cm in men.

RESULTS

The sex ratio of the subjects was 1.9:1 (male:female) and their age was 47.7+/-10.0 years (mean+/-SD). In univariate analysis, abdominal obesity was significantly associated with the frequency of colorectal adenoma (26.5% "yes" vs 16.9% "no"; p<0.001). The frequency of colorectal adenoma was significantly higher among males, older patients, current smokers, and subjects with fasting hyperglycemia (>/=100 mg/dL) or fatty liver (p<0.05). Multivariate analysis identified that male sex (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.0-2.2), old age (age >/=60 years; OR, 6.7; 95% CI, 3.5-12.5), and abdominal obesity (OR, 1.5; 95% CI, 1.0-2.2) were independent risk factors for colorectal adenoma (p<0.05). The frequency of multiple adenomas (more than two sites) was also significantly higher in subjects with abdominal obesity. However, the effect of abdominal obesity on the development of colorectal adenoma decreased in elderly people.

CONCLUSIONS

Abdominal obesity is an independent risk factor for colorectal adenoma and its multiplicity, especially in younger people in South Korea.

Impact of diabetes mellitus on the prognosis of patients with oral squamous cell carcinoma: a retrospective cohort study

BACKGROUND

Diabetes mellitus (DM) is a prevalent chronic metabolic disease reported to affect the treatment outcomes of malignancies. This study explores the impact of diabetes on the prognosis of oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Clinicopathological characteristics and survival in terms of overall survival (OS), recurrence-free survival (RFS), and cancer-specific survival (CSS) of patients with OSCC who underwent surgical intervention at the Taipei Veterans General Hospital between 2002 and 2005 were stratified by diabetic status and compared.

RESULTS

Patients with DM tend to have a lower OS, RFS, and CSS compared with nondiabetics (adjusted hazard ratio [HR] = 2.22, 2.42, and 2.16, respectively) even in less aggressive tumor stages (stage I and II). In advanced tumors, diabetic patients who were not prescribed adjuvant therapy had a significantly higher recurrence rate than nondiabetic patients (HR = 2.66). However, there was no significant difference in treatment outcome in patients with locally advanced tumors amenable to receive adjuvant therapy, even with the delayed initiation of adjuvant therapy in the DM group (49.1 +/- 22.3 days vs. 40.0 +/- 16.6 days, P = .04). DM was also associated with a higher frequency of perineural invasion (adjusted odds ratio [OR] = 2.53).

CONCLUSION

DM status could be a prognostic factor for OSCC, particularly for its effect in the survival and perineural invasion. Although diabetes-associated comorbidities may impair decision making toward less aggressive therapeutic modality, adjuvant treatment may be essential for DM patients to improve their survival.