Association of obesity, serum glucose and lipids with the risk of advanced colorectal adenoma and cancer: a case-control study in Korea

The Relationship Between Serum Lipids and the Formation of Colorectal Polyps

BACKGROUND AND AIMS

Obesity, metabolic syndrome, and hyperlipidemia are known as risk factors for colorectal tumors. Colorectal polyps are accepted as potential precursors of colorectal cancer (CRC). This study was designed to clarify the association between the levels of serum lipids and the presence of colorectal polyps.

METHODS

This study was conducted at Basaksehir Cam and Sakura City Hospital, Gastroenterological Surgery Clinic, Istanbul, Turkey. We retrospectively analyzed patients who underwent colonoscopy with serum lipid profile within one month for a one-year period. Groups were analyzed in terms of the correlation between hyperlipidemia and the formation of polyps. The study group was also evaluated in terms of the polyp type, localization, and number.

RESULTS

Among 453 patients, females were 248 and males were 211, with a mean age of 56.7. The study and control groups involved 259 and 194 patients, respectively. The age and serum levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglyceride (TG) were found to be statistically significant in terms of polyp presence and number (p < 0.05).

CONCLUSION

Colorectal polyps are well-known precursors of CRC. We found that the combination of elevated serum levels of low-density lipoprotein cholesterol, total cholesterol, and triglycerides may be a risk predictor for the presence of colorectal polyps, which can be advantageous in cancer screening.

Association of clinical characteristics and recurrence of conventional colorectal adenomas with patient age: a single-center study

OBJECTIVES

We performed a clinical study comparing early-onset and late-onset conventional colorectal adenomas (CCRAs) since little is known about the differences in their characteristics.

METHODS

Pearson's chi-square test and the Kruskal‒Wallis test were used to compare basic information. MCAR tests and multiple imputation were performed to complete missing values. Multivariate logistic analysis and propensity score matching were used to identify the risk factors for recurrence.

RESULTS

We included 2793 patients (688 with early-onset CCRAs and 2105 with late-onset CCRAs) from January 2017 to December 2021. Patients with early-onset CCRAs had higher levels of Hb, ALB, and triglycerides but lower HDL levels and N/L ratios. Moreover, we found that more early-onset CCRAs were in the left colon than late-onset CCRAs, and the size of early-onset CCRAs was larger. Early-onset CCRAs tended to lack pedicles compared to late-onset CCRAs. Additionally, the ratio of EMR and APC in early-onset CCRAs was higher than that in late-onset CCRAs, and the ratio of ESD and surgery for late-onset CCRAs was higher. We found that age ≥ 50 years, abnormal vessels, drinking alcohol, and DB and ALB levels may be risk factors for recurrence, while the LDL level may be a protective factor. Finally, analysis of cumulative recurrence rates after PSM showed that patients with late-onset CCRAs exhibited higher recurrence rates (P < 0.05).

CONCLUSION

Compared with late-onset CCRAs, early-onset CCRAs were associated with higher triglyceride levels, lower HDL levels, and larger tumor volumes. Age ≥ 50 years, abnormal vessels, alcohol consumption, and DB and ALB levels were independent risk factors for recurrence of CCRAs.

Changes in the Fecal Metabolome Accompany an Increase in Aberrant Crypt Foci in the Colon of C57BL/6 Mice Fed with a High-Fat Diet

High-fat diet (HFD)-induced obesity is a risk factor for colon cancer. Our previous data show that compared to an AIN-93 diet (AIN), a HFD promotes azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) formation and microbial dysbiosis in C57BL/6 mice. To explore the underlying metabolic basis, we hypothesize that AOM treatment triggers a different fecal metabolomic profile in C57BL/6 mice fed the HFD or the AIN. We found that 65 of 196 identified metabolites were significantly different among the four groups of mice (AIN, AIN + AOM, HFD, and HFD + AOM). A sparse partial least squares discriminant analysis (sPLSDA) showed that concentrations of nine fecal lipid metabolites were increased in the HFD + AOM compared to the HFD, which played a key role in overall metabolome group separation. These nine fecal lipid metabolite concentrations were positively associated with the number of colonic ACF, the cell proliferation of Ki67 proteins, and the abundance of dysbiotic bacteria. These data suggest that the process of AOM-induced ACF formation may increase selective fecal lipid concentrations in mice fed with a HFD but not an AIN. Collectively, the accumulation of these critical fecal lipid species may alter the overall metabolome during tumorigenesis in the colon.

The Relationship Between Colorectal Polyps and Serum Lipid Levels: A Systematic Review and Meta-analysis

Colorectal polyp has been considered as the precancerous lesion of colorectal cancer, to which serum lipid levels are closely related. At present, there is no consensus on the relationship between colorectal polyps and serum lipid levels. We performed a meta-analysis to explore the effects of lipid levels on colorectal polyps. Relevant articles published from 2000 to 2020 were searched in PubMed, Web of Science, EMBASE, and Cochrane Library databases. The mean value and SD of serum lipid indexes and body mass index in colorectal polyps groups and control groups were extracted from the included articles. Combined weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated to assess the effect size of serum lipid levels on colorectal polyps. The publication bias of the included studies were assessed based on the Egger test. Thirty-seven articles containing 19,464 cases and 63,979 controls were included. There were no significant publication bias. The levels of high-density lipoprotein cholesterol in the cases were lower than those in the controls (WMD: -2.589 mg/dL, 95% CI: -3.273, -1.906). While the levels of triglyceride (WMD: 16.933 mg/dL, 95% CI: 13.131, 20.736), total cholesterol (WMD: 5.561 mg/dL, 95% CI: 3.477, 7.645), low-density lipoprotein cholesterol (WMD: 3.109 mg/dL, 95% CI: 0.859, 5.359) and body mass index (WMD: 0.747 mg/dL, 95% CI: 0.588, 0.906) were higher in the cases. Colorectal polyps were associated with serum lipid levels and obesity. Hyperlipidemia and obesity may be the risk factors for colorectal polyps.

Comparison of some biochemical markers between early‐onset and late‐onset colorectal precancerous lesions: A single‐center retrospective study

Objective

Given that the onset of diseases including colorectal cancer precursors is affecting younger individuals and that obesity is an important risk factor for early‐onset, we conducted a study to explore the biochemical profile of differences in serum between early‐onset patients and late‐onset colorectal precancerous lesions.

Methods

A total of 1447 patients, including 469 early‐onset patients and 978 late‐onset patients, were enrolled from the First Affiliated Hospital of Nanchang University (FAHNU), of which there were 311 sessile serrated adenoma/polyps (SSA/P) and 1136 normal adenomas. The distribution of the included categorical variables was compared via Pearson's chi‐squared test, whereas continuous variables were compared by using the nonparametric Kruskal–Wallis test and anova.

Results

Compared with late‐onset patients, the levels of total bilirubin and HDL‐C were lower (p < 0.05), whereas triglyceride and uric acid levels were higher, in early‐onset patients. Interestingly, in the subgroup analysis, triglyceride and uric acid levels remained at higher levels, whereas HDL‐C remained at lower levels, in early‐onset patients than in late‐onset patients. Other characteristics, such as LDL‐C, drinking, γ‐GT, and the N/L ratio, were similar between the two groups. An additional analysis of the association of tumor size with markers showed that lower levels of HDL‐C and higher levels of uric acid were associated with increased tumor size (p < 0.05).

Conclusions

Early‐onset CRC precursor cases exhibit higher levels of triglycerides and lower levels of HDL‐C than late‐onset cases. Additionally, levels of HDL‐C are negatively associated with tumor size, whereas uric acid was positively correlated with tumor size.

Relationship between serum lipid level and colorectal cancer: a systemic review and meta-analysis

OBJECTIVE

Investigative studies report contradictory results of the relationship between serum lipid levels and the risk of colorectal cancer (CRC). We conducted a meta-analysis of prospective published studies to clarify the relationship between serum lipid and CRC risk.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed and Embase from inception until December 2020.

ELIGIBILITY CRITERIA

We considered prospective cohort and case-control studies that evaluated differences in serum lipid levels with the risk of developing CRC.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers screened and included the studies using standardised electronic data extraction forms. The relative risks of the studies were combined with random-effect and fixed-effect models and were analysed for heterogeneity, publication bias and sensitivity.

RESULTS

Twenty-four prospective studies, including 4 224 317 individuals with 29 499 CRC cases, were included in the meta-analysis. The total pooled risk ratio (RR) for high vs low concentrations of triglyceride (TG) concentrations was reported at 1.21 (95% CI 1.09 to 1.34; I²=46.8%), total cholesterol (TC) was at 1.15 (95% CI 1.08 to 1.22; I²=36.8%), high-density lipoprotein cholesterol (HDL-C) was 0.86 (95% CI 0.77 to 0.97; I²=28.8%) and low-density lipoprotein cholesterol (LDL-C) was observed at 1.03 (95% CI 0.75 to 1.41; I²=69.4%).

CONCLUSIONS

This meta-analysis shows that high levels of serum TG and TC are positively correlated with the incidence rate of CRC, while high levels of serum HDL-C are negatively correlated with CRC incidence rate. Furthermore, no association was found between LDL-C and the risk of developing CRC. Nevertheless, the heterogeneity brought about by comparative methods, demographic differences and pathological differences between the research subjects limits the effectiveness of the overall pooled results.

Construction, Validation, and Visualization of Two Web-Based Nomograms to Predict Overall and Cancer-Specific Survival in Patients with Gastric Cancer and Lung Metastases

Background

The lung is one of the most common sites of metastasis in gastric cancer. Our study developed two nomograms to achieve individualized prediction of overall survival (OS) and cancer-specific survival (CSS) in patients with gastric cancer and lung metastasis (GCLM) to better guide follow-up and planning of subsequent treatment.

Methods

We reviewed data of patients diagnosed with GCLM in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015. The endpoints of the study were the OS and CSS. We used the “caret” package to randomly divide patients into training and validation cohorts in a 7 : 3 ratio. Multivariate Cox regression analysis was performed using univariate Cox regression analysis to confirm the independent prognostic factors. Afterward, we built the OS and CSS nomograms with the “rms” package. Subsequently, we evaluated the two nomograms through calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Finally, two web-based nomograms were built on the basis of effective nomograms.

Results

The OS analysis included 640 patients, and the results of the multivariate Cox regression analysis showed that grade, chemotherapy, and liver metastasis were independent prognostic factors for patients with GCLM. The CSS analysis included 524 patients, and the results of the multivariate Cox regression analysis showed that the independent prognostic factors for patients with GCLM were chemotherapy, liver metastasis, marital status, and tumor site. The ROC curves, calibration curves, and DCA revealed favorable predictive power in the OS and CSS nomograms. We created web-based nomograms for OS (https://zhenghh.shinyapps.io/aclmos/) and CSS (https://zhenghh.shinyapps.io/aslmcss/).

Conclusions

We created two web-based nomograms to predict OS and CSS in patients with GCLM. Both web-based nomograms had satisfactory accuracy and clinical usefulness and may help clinicians make individualized treatment decisions for patients.

Analysis of research on metabolic syndrome in cancer survivors using topic modeling and social network analysis

This study aimed to identify the relationships between the keywords of research on metabolic syndrome in cancer survivors and the entire knowledge research structure, through topic extraction from a macro perspective. From six electronic databases, 918 studies published between 1996 and 2019 were identified and reviewed, and 365 were included. Keyword network analysis and topic modeling were applied to examine the studies. In keyword network analysis, "obesity," "treatment," "breast cancer," "body mass index," and "prostate cancer" were the major keywords, whereas "obesity" and "breast" were the dominant keywords and ranked high in frequency, degree centrality, and betweenness centrality. In topic modeling, five clustered topics emerged, namely metabolic syndrome component, post CTX(chemotherapy) sequence, prostate-specific antigen-sensitive plot, lifestyle formation, and insulin fluctuation. Topic 2, post CTX sequence, showed the highest salience in earlier studies, but this has decreased over time, and the themes of the studies have also broadened. This study may provide critical basic data for determining the changing trends of research on metabolic syndrome in cancer survivors and for predicting the direction of future research through the visualization of the effects and interactions between the major keywords in research on metabolic syndrome in cancer survivors.

Resting heart rate is associated with colorectal advanced adenoma

Background and aims

Resting heart rate is an independent predictor of colorectal cancer (CRC) development and CRC-related mortality. However, little is known about the relationship between resting heart rate and colorectal adenoma development. We aimed to investigate this association in a population who underwent screening colonoscopy.

Methods

Among 39,021 patients who underwent both electrocardiogram and screening colonoscopy during routine health examinations at the Seoul National University Bundang Hospital, Health Promotion Center, Korea from January 2014 to July 2019, 1,344 patients had advanced adenoma. We performed 1:1 propensity score (PS) matching to establish a control group that mitigated the confounding effects of age and sex. We performed multivariate logistic regression analyses to identify the independent risk factors of advanced adenoma development.

Results

Resting heart rate was significantly higher in the advanced adenoma group than in the control group. The prevalence of advanced polyp increased across the quartiles of resting heart rate. Patients with higher resting heart rates were more likely to be older, smokers, and have increased blood pressure and DM and less likely to engage in active exercises than those with lower resting heart rates. Patients with higher resting heart rates had higher serum glucose, triglyceride, hemoglobin A1C, and insulin levels and lower high-density lipoprotein cholesterol levels. Patients with resting heart rate in the highest quartile (≥71 bpm) still showed significantly increased odds ratio (OR) of advanced adenoma development (OR: 1.379, 95% confidence interval: 1.099–1.731, p = 0.006).

Conclusions

High resting heart rate was a meaningful independent risk factor of advanced adenoma development.

Azoxymethane Alters the Plasma Metabolome to a Greater Extent in Mice Fed a High-Fat Diet Compared to an AIN-93 Diet

Consumption of a high-fat diet (HFD) links obesity to colon cancer in humans. Our data show that a HFD (45% energy fat versus 16% energy fat in an AIN-93 diet (AIN)) promotes azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) formation in a mouse cancer model. However, the underlying metabolic basis remains to be determined. In the present study, we hypothesize that AOM treatment results in different plasma metabolomic responses in diet-induced obese mice. An untargeted metabolomic analysis was performed on the plasma samples by gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). We found that 53 of 144 identified metabolites were different between the 4 groups of mice (AIN, AIN + AOM, HFD, HFD + AOM), and sparse partial least-squares discriminant analysis showed a separation between the HFD and HFD + AOM groups but not the AIN and AIN + AOM groups. Moreover, the concentrations of dihydrocholesterol and cholesterol were inversely associated with AOM-induced colonic ACF formation. Functional pathway analyses indicated that diets and AOM-induced colonic ACF modulated five metabolic pathways. Collectively, in addition to differential plasma metabolomic responses, AOM treatment decreases dihydrocholesterol and cholesterol levels and alters the composition of plasma metabolome to a greater extent in mice fed a HFD compared to the AIN.

Insulin-Like Growth Factor 1 (IGF-1) Signaling in Glucose Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common aggressive carcinoma types worldwide, characterized by unfavorable curative effect and poor prognosis. Epidemiological data re-vealed that CRC risk is increased in patients with metabolic syndrome (MetS) and its serum components (e.g., hyperglycemia). High glycemic index diets, which chronically raise post-prandial blood glucose, may at least in part increase colon cancer risk via the insulin/insulin-like growth factor 1 (IGF-1) signaling pathway. However, the underlying mechanisms linking IGF-1 and MetS are still poorly understood. Hyperactivated glucose uptake and aerobic glycolysis (the Warburg effect) are considered as a one of six hallmarks of cancer, including CRC. However, the role of insulin/IGF-1 signaling during the acquisition of the Warburg metabolic phenotypes by CRC cells is still poorly understood. It most likely results from the interaction of multiple processes, directly or indirectly regulated by IGF-1, such as activation of PI3K/Akt/mTORC, and Raf/MAPK signaling pathways, activation of glucose transporters (e.g., GLUT1), activation of key glycolytic enzymes (e.g., LDHA, LDH5, HK II, and PFKFB3), aberrant expression of the oncogenes (e.g., MYC, and KRAS) and/or overexpression of signaling proteins (e.g., HIF-1, TGF-β1, PI3K, ERK, Akt, and mTOR). This review describes the role of IGF-1 in glucose metabolism in physiology and colorectal carcinogenesis, including the role of the insulin/IGF system in the Warburg effect. Furthermore, current therapeutic strategies aimed at repairing impaired glucose metabolism in CRC are indicated.

Elevated serum triglyceride predicts recurrence of colorectal polyps in patients with advanced adenomas

Background

Recurrence of colorectal polyps is common and impacted by various factors. This study was performed to explore the association between lipid profiles and recurrence of colorectal polyps.

Methods

This study retrospectively analyzed the lipid profiles of 435 patients who underwent colonoscopy with removal of colorectal polyps and assessed recurrence of polyps by follow-up colonoscopy. Multivariate regression logistic analysis was used to evaluate the association between lipid profiles and polyp recurrence.

Results

During the 1.5-year follow-up, recurrence of colorectal polyps was observed in 135 of 435 patients (30.34%). Patients with recurrent polyps showed a higher level of triglycerides (P = 0.006) and lower levels of high-density lipoprotein cholesterol (P = 0.008) and apolipoprotein A1 (P = 0.033). The multivariate regression logistic model suggested that an elevated triglyceride level was an independent risk factor for polyp recurrence (odds ratio, 1.55; 95% confidence interval, 1.02–2.35; P = 0.039) in patients with advanced adenoma.

Conclusions

Lipid profiles are associated with recurrence of colorectal polyps. An elevated triglyceride level is an independent risk predictor of polyp recurrence in patients with advanced adenoma.

Elevated serum triglyceride and low-density lipoprotein cholesterol promotes the formation of colorectal polyps

BACKGROUND

Hyperlipidaemia may be a potential risk factor for the occurrence of intestinal polyps. This study aimed to evaluate correlation between lipidaemia and the formation of colorectal polyps.

METHODS

One hundred and fourteen patients with colorectal polyps and forty-eight healthy controls were included in this study. Colonoscopies were performed for all patients and controls within 1 week before blood samples were taken. The concentrations of serum lipids and lipoproteins were measured simultaneously using an automatic biochemical analyser. The colorectal lesions were classified based on pathological characteristics, and four types were identified in the study: hyperplastic polyp (HP), tubular adenoma (TA), tubulovillous adenoma (TVA) and adenoma with high-grade dysplasia (A-HGD). Advanced adenoma was classified according to the number, size and histological type of polyps.

RESULTS

The value of low-density lipoprotein cholesterol (LDL-C) was significantly higher in the group with advanced adenoma than in the controls (p < 0.05). Moreover, the LDL-C values in the HP and TA groups were higher when compared to that of controls (p < 0.05). Obesity, age, and increased TG and LDL-C were independent risk factors for the formation of colorectal polyps. The cut-off values of triglyceride (TG) and LDL-C to distinguish polyp patients from healthy controls were 0.96 mmol/L (AUC = 0.604, p = 0.036) and 3.05 mmol/L (AUC = 0.654, p = 0.002). The combined use of increased LDL-C and TG levels to distinguish polyp patients was effective, with a sensitivity of 50.0% and a specificity of 89.6% (AUC = 0.733, p < 0.01).

CONCLUSIONS

Colorectal polyps are more often found in obese and older patients. Increased LDL-C and TG were correlated with the occurrence of polyps. Combination of the two serum indicators was useful to assess risk of colorectal lesions, maybe more effective in screening hyperplastic polyp, tubular adenoma and advanced adenoma.

Elevation of n-3/n-6 PUFAs ratio suppresses mTORC1 and prevents colorectal carcinogenesis associated with APC mutation

Although epidemiological and preclinical studies have shown the preventative effect of n-3 polyunsaturated fatty acids (PUFAs) on colorectal cancer (CRC), the underlying molecular mechanisms are not clear. In this study, we revealed that elevation of n-3/n-6 PUFAs ratio suppress the mechanistic target of rapamycin complex 1 (mTORC1) and prevent colorectal tumorigenesis. The transgenic expression of fat-1, a desaturase that catalyzes the conversion of n-6 to n-3 PUFAs and produces n-3 PUFAs endogenously, repressed colorectal tumor cell growth and remarkably reduced tumor burden, and alleviated anemia as well as hyperlipidemia in APCMin/+ (adenomatous polyposis coli) mice, a classic CRC model that best simulates most clinical cases. In contrast to arachidonic acid (AA, C20:4 n-6), either Docosahexaenoic acid (DHA, C22:6 n-3), eicosapentaenoic acid (EPA, C20:5 n-3), or a combination of DHA and AA, efficiently inhibited the proliferation of CRC cell lines and promoted apoptosis in these cells. The ectopic expression of fat-1 had similar effects in colon epithelial cells with APC depletion. Mechanistically, elevation of n-3/n-6 ratio suppressed mTORC1 activity in tumors of APCMin/+ mice, CRC cell lines with APC mutation, and in normal colon epithelial cells with APC depletion. In addition, elevation of n-3/n-6 ratio repressed mTORC1 activity and inhibited adipogenic differentiation in preadipocytes with APC knockdown, as well as alleviated hyperlipidemia in APCMin/+ mice. Taken together, our findings have provided novel insights into the potential mechanism by which increase in n-3/n-6 PUFAs ratio represses CRC development, and also a new rationale for utilizing n-3 PUFAs in CRC prevention and treatment.

Inhibition of FASN expression enhances radiosensitivity in human non-small cell lung cancer

Fatty acid synthase (FASN) is the key enzyme required for the de novo synthesis of long-chain fatty acids. FASN has been observed to be overexpressed in the majority of cancer tissues, and its expression is associated with a poor prognosis, potentially mediated by resistance to drug or radiation. The present study investigated whether the downregulation of FASN in non-small cell lung cancer (NSCLC) may increase radiosensitivity. A lentiviral vector containing short hairpin RNA targeted to FASN (pSIH-H1-Puro-shFASN) was successfully constructed and transfected into A549 cells to knockdown the gene by RNA interference. pSIH-H1-Puro-shFASN was used as the experimental group, while pSIH-H1-Puro-shGFP was used as a control group. The mRNA expression levels of FASN were determined using quantitative polymerase chain reaction. In addition, cell proliferation was measured using cell counting kit-8 assay, and colony formation assay was performed to determine the radiosensitizing effect of FASN knockdown. The cell cycle distribution and apoptotic rates were analyzed using flow cytometry, while western blot analysis was used to assess the expression of DNA-dependent protein kinase catalytic subunit protein, which is associated with DNA double-strand break (DSB) repair. The results of the present study revealed that NSCLC cells are more sensitive to radiation following the knockdown of FASN. Furthermore, the increased radiosensitivity may be associated with increased proliferation, promotion of apoptosis and cell cycle arrest in the G2/M phase. Furthermore, downregulated FASN expression reduced the levels of DNA DSB repair-associated proteins following treatment with radiation. These results indicate that silencing FASN may sensitize NSCLC cells to radiation treatment. Therefore, FASN may be a potential novel therapeutic target to improve the response of NSCLCs to radiation therapy.

Adiponectin, Leptin, IGF-1, and Tumor Necrosis Factor Alpha As Potential Serum Biomarkers for Non-Invasive Diagnosis of Colorectal Adenoma in African Americans

The potential role of adiponectin, leptin, IGF-1, and tumor necrosis factor alpha (TNF-α) as biomarkers in colorectal adenoma is not clear. Therefore, we aimed to investigate the blood serum levels of these biomarkers in colorectal adenoma. The case-control study consisted of serum from 180 African American patients with colon adenoma (cases) and 198 healthy African Americans (controls) at Howard University Hospital. We used ELISA for adiponectin, leptin, IGF-1, and TNF-α detection and quantification. Statistical analysis was performed by t-test and multivariate logistic regression. The respective differences in median leptin, adiponectin, IGF-1, and TNF-α levels between control and case groups (13.9 vs. 16.4), (11.3 vs. 46.0), (4.5 vs. 12.9), and (71.4 vs. 130.8) were statistically significant (P < 0.05). In a multivariate model, the odds ratio for adiponectin, TNF-α, and IGF-1 were 2.0 (95% CI = 1.6-2.5; P < 0.001), 1.5 (95% CI = 1.5(1.1-2.0); P = 0.004), and 1.6 (95% CI = 1.3-2.0; P < 0.001), respectively. There was a positive correlation between serum adiponectin and IGF-1 concentrations with age (r = 0.17, P < 0.001 and r = 0.13, P = 0.009), TNF-α, IGF-1, and leptin concentration with body mass index (BMI) (r = 0.44, P < 0.001; r = 0.11, P = 0.03; and r = 0.48, P < 0.001), respectively. Also, there was a negative correlation between adiponectin and leptin concentrations with BMI (r = -0.40, P < 0.001), respectively. These data support the hypothesis that adiponectin, IGF-1, and TNF-α high levels correlate with higher risk of colon adenoma and can thus be used for colorectal adenomas risk assessment.

Association between investigator-measured body-mass index and colorectal adenoma: a systematic review and meta-analysis of 168,201 subjects

The objective of this meta-analysis is to evaluate the odds of colorectal adenoma (CRA) in colorectal cancer screening participants with different body mass index (BMI) levels, and examine if this association was different according to gender and ethnicity. The EMBASE and MEDLINE were searched to enroll high quality observational studies that examined the association between investigator-measured BMI and colonoscopy-diagnosed CRA. Data were independently extracted by two reviewers. A random-effects meta-analysis was conducted to estimate the summary odds ratio (SOR) for the association between BMI and CRA. The Cochran’s Q statistic and I² analyses were used to assess the heterogeneity. A total of 17 studies (168,201 subjects) were included. When compared with subjects having BMI < 25, individuals with BMI 25–30 had significantly higher risk of CRA (SOR 1.44, 95% CI 1.30–1.61; I² = 43.0%). Subjects with BMI ≥ 30 had similarly higher risk of CRA (SOR 1.42, 95% CI 1.24–1.63; I² = 18.5%). The heterogeneity was mild to moderate among studies. The associations were significantly higher than estimates by previous meta-analyses. There was no publication bias detected (Egger’s regression test, p = 0.584). Subgroup analysis showed that the magnitude of association was significantly higher in female than male subjects (SOR 1.43, 95% CI 1.30–1.58 vs. SOR 1.16, 95% CI 1.07–1.24; different among different ethnic groups (SOR 1.72, 1.44 and 0.88 in White, Asians and Africans, respectively) being insignificant in Africans; and no difference exists among different study designs. In summary, the risk conferred by BMI for CRA was significantly higher than that reported previously. These findings bear implications in CRA risk estimation.

Abdominal obesity and colorectal cancer risk: systematic review and meta-analysis of prospective studies

The association between abdominal obesity (as measured by waist circumference (WC) and waist-to-hip ratio (WHR)) and colorectal cancer (CRC) has not been fully quantified, and the magnitude of CRC risk associated with abdominal obesity is still unclear. A meta-analysis of prospective studies was performed to elucidate the CRC risk associated with abdominal obesity. Pubmed and Embase were searched for studies assessing the association between abdominal obesity and CRC risk. Relative risks (RRs) with 95% confidence intervals (95% CIs) were pooled using random-effects model of meta-analysis. Nineteen prospective cohort studies from eighteen publications were included in this meta-analysis. A total of 12,837 CRC cases were identified among 1,343,560 participants. Greater WC and WHR were significantly associated with increased risk of total colorectal cancer (WC: RR 1.42, 95% CI 1.30, 1.55; WHR: RR 1.39, 95% CI 1.25, 1.53), colon cancer (WC: RR 1.53, 95% CI 1.36, 1.72; WHR: 1.39, 95% CI 1.18, 1.63), and rectal cancer (WC: RR 1.20, 95% CI 1.03, 1.39; WHR: RR 1.22, 95% CI 1.05, 1.42). Subgroup analyses further identified the robustness of the association above. No obvious risk of publication bias was observed. In summary, abdominal obesity may play an important role in the development of CRC.

Meta-analysis of the clinicopathological characteristics and peri-operative outcomes of colorectal cancer in obese patients

BACKGROUND

The effect of obesity on the clinicopathological characteristics of colorectal cancer (CRC) has not been clearly characterized. This meta-analysis assesses the pathological and perioperative outcomes of obese patients undergoing surgical resection for CRC.

METHODS

Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Databases were searched for studies reporting outcomes for obese and non-obese patients undergoing primary CRC resection, based on body-mass index measurement. Results were reported as mean differences or pooled odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

A total of 2183 citations were reviewed; 29 studies comprising 56,293 patients were ultimately included in the analysis, with an obesity rate of 19.3%. Obese patients with colorectal cancer were more often female (OR 1.2, 95% CI 1.1-1.2, p<0.001) but there was no difference in the proportion of rectal cancers, T4 tumours, tumour differentiation or margin positivity. Obese patients were significantly more likely to have lymph node metastases (OR 1.2, 95% CI 1.1-1.2, p<0.001), have a lower nodal yield, were associated with a longer duration of surgery, more blood loss and conversions to open surgery (OR 2.6, 95% CI 1.6-4.0, p<0.001) but with no difference in length of stay or post-operative mortality.

CONCLUSION

This meta-analysis demonstrates that obese patients undergoing resection for CRC are more likely to have node positive disease, longer surgery and higher failure rates of minimally invasive approaches. The challenges of colorectal cancer resection in obese patients are emphasized.

Chemopreventive and Chemotherapeutic Effects of Fish Oil derived Omega-3 Polyunsaturated Fatty Acids on Colon Carcinogenesis

Colorectal cancer is the third most common cause of cancer related death in the world. Multiple lines of evidence suggest that there is an association between consumption of dietary fat and colon cancer risk. Not only the amount but also the type and the ratio of fatty acids comprising dietary fats consumed have been implicated in the etiology and pathogenesis of colon cancer. Omega-3 (n-3) polyunsaturated fatty acids (PUFAs), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have been known to inhibit development of colon cancer by downregulating the expression of genes involved in colon carcinogenesis and also by altering the membrane lipid composition. Data from laboratory, epidemiological, and clinical studies substantiate the beneficial role of n-3 PUFAs in preventing colitis and subsequent development of colon cancer. In addition, recent studies suggest that some n-3 PUFAs can be effective as an adjuvant with chemotherapeutic agents and other natural anticancer compounds in the management of colon cancer. In this review, we discuss chemopreventive and therapeutic effects of fish oil derived long chain n-3 PUFAs, particularly EPA and DHA, with focus on synergetic effects of which they exert when combined with chemotherapeutic agents and other natural compounds.

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.

Asian consensus on the relationship between obesity and gastrointestinal and liver diseases

The incidence of obesity is increasing in Asia, with implications on gastrointestinal (GI) and liver diseases. The Gut and Obesity in Asia Workgroup comprises regional experts with the aim of studying relationship between obesity and the GI and liver diseases in Asia. Through literature review and the modified Delphi process, consensus statements examining the impact of obesity on esophageal, gastric, pancreatic, colorectal, and liver diseases, exploring relationship between gut microbiome and obesity, and assessing obesity therapies have been produced by the Gut and Obesity in Asia Workgroup. Sixteen experts participated with 9/15 statements having strong consensus (>80% agreement). The prevalence of obesity in Asia is increasing (100% percentage agreement in brackets), and this increased prevalence of obesity will result in a greater burden of obesity-related GI and liver diseases (93.8%). There was consensus that obesity increases the risk of gastric cancer (75%) and colorectal neoplasia (87.5%). Obesity was also associated with Barrett's esophagus and esophageal adenocarcinoma (66.7%) and pancreatic cancer (66.7%) in Asia. The prevalence of non-alcoholic fatty liver disease (NAFLD) in Asia is on the rise (100%), and the risk of NAFLD in Asia (100%) is increased by obesity. Obesity is a risk factor for the development of hepatocellular carcinoma (93.8%). Regarding therapy, it was agreed that bariatric surgery was an effective treatment modality for obesity (93.8%) but there was less agreement on its benefit for NAFLD (62.5%). These experts' consensus on obesity and GI diseases in Asia forms the basis for further research, and its translation into addressing this emerging issue.

8q24 Polymorphisms and Diabetes Mellitus Regulate Apolipoprotein A-IV in Colorectal Carcinogenesis

BACKGROUND

Here, we explored the genetic interactions between diabetes and oncogenic single-nucleotide polymorphisms (SNPs) that determine colorectal cancer (CRC) morbidity.

METHODS

8q24 rs6983267 polymorphism analysis and cDNA microarray were performed in 107 CRCs to identify the genes associated with diabetes and the oncogenic SNP. Then clinical significance of the gene was validated in 132 CRCs. Meta-analysis of microarray data and diabetic comorbidity was performed.

RESULTS

Of genes associated with a minor SNP allele at 8q24, diabetes, and MYC overexpression, apolipoprotein A-IV (ApoA-IV) was associated with oncogenesis and poor prognosis in CRC patients. Patients with high ApoA-IV expression showed significantly poorer prognosis by univariate and multivariate analysis. Meta-analysis revealed lipid metabolism was associated with ApoA-IV-related oncogenesis in diabetic patients.

CONCLUSIONS

Changes in lipid metabolism associated with aberrant expression of ApoA-IV were risks for CRC oncogenesis.

Association between markers of glucose metabolism and risk of colorectal cancer

OBJECTIVES

Independent epidemiological studies have evaluated the association between markers of glucose metabolism (including fasting glucose, fasting insulin, homeostasis model of risk assessment-insulin resistance (HOMA-IR), glycated haemoglobin (HbA1c) and C peptide) and the risk of colorectal cancer (CRC). However, such associations have not been systematically analysed and no clear conclusions have been drawn. Therefore, we addressed this issue using a meta-analysis approach.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed and EMBASE were searched up to May 2015.

PRIMARY AND SECONDARY OUTCOME MEASURES

Either a fixed-effects or random-effects model was adopted to estimate overall ORs for the association between markers of glucose metabolism and the risk of CRC. In addition, dose-response, meta-regression, subgroup and publication bias analyses were conducted.

RESULTS

35 studies involving 25 566 patients and 5 706 361 participants were included. Higher levels of fasting glucose, fasting insulin, HOMA-IR, HbA1c and C peptide were all significantly associated with increased risk of CRC (fasting glucose, pooled OR=1.12, 95% CI 1.06 to 1.18; fasting insulin, pooled OR=1.42, 95% CI 1.19 to 1.69; HOMA-IR, pooled OR=1.47, 95% CI 1.24 to 1.74; HbA1c, pooled OR=1.22, 95% CI 1.02 to 1.47 (with borderline significance); C peptide, pooled OR=1.27, 95% CI 1.08 to 1.49). Subgroup analysis suggested that a higher HOMA-IR value was significantly associated with CRC risk in all subgroups, including gender, study design and geographic region. For the relative long-term markers, the association was significant for HbA1c in case-control studies, while C peptide was significantly associated with CRC risk in both the male group and colon cancer.

CONCLUSIONS

The real-time composite index HOMA-IR is a better indicator for CRC risk than are fasting glucose and fasting insulin. The relative long-term markers, HbA1c and C peptide, are also valid predictors for CRC risk. Considering the included case-control studies in the current analysis, more cohort studies are warranted to enhance future analysis.

Blood Lipid Concentrations and Colorectal Adenomas: A Systematic Review and Meta-Analysis of Colonoscopy Studies in Asia, 2000-2014

It is unclear whether dyslipidemia is associated with risk of colorectal neoplasia. The incidence of both conditions is increasing in Asia, motivating a number of new studies from this region. We performed a systematic literature search of Asian colonoscopy-based studies that collected blood lipid concentrations at the time of endoscopy. Persons found to have colorectal adenoma were considered cases, and those found to be adenoma-free were considered controls. Seventeen studies published between 2000 and 2014 met inclusion criteria, collectively enrolling 17,387 cases and 30,427 controls. Mean differences and adjusted odds ratios were summarized with random-effects meta-analyses. Compared with controls, cases had higher total cholesterol (mean difference (MD) = 2.4 mg/dL, 95% confidence interval (CI): 0.2, 4.6), higher low-density lipoprotein cholesterol (MD = 1.3 mg/dL, 95% CI: 0.1, 2.6), higher triglyceride (MD = 16.4 mg/dL, 95% CI: 11.2, 21.5), and lower high-density lipoprotein (HDL) cholesterol (MD = -2.1 mg/dL, 95% CI: -2.7, -1.6) concentrations. Based on adjusted odds ratios, associations for 40-mg/dL-higher triglyceride levels (odds ratio = 1.13, 95% CI: 1.05, 1.21) and 10-mg/dL-higher HDL cholesterol levels (odds ratio = 0.96, 95% CI: 0.92, 1.00) achieved statistical significance. Persons with adenoma were more likely to have unfavorable cholesterol profiles at the time of colonoscopy than those without adenoma. The most convincing evidence for an association between dyslipidemia and colorectal neoplasia was observed for hypertriglyceridemia.

Hypertension, serum lipids and cancer risk: A review of epidemiological evidence

Although the association between blood pressure, serum lipids and cancer risk has been investigated, the results are controversial. The aim of this literature review was to examine the epidemiological evidence and provide overview of the association between blood pressure, serum lipids and cancer risk. The arterial hypertension is closely linked with renal cell cancer development. Risk of renal cell cancer was 2-4 times higher for persons with arterial hypertension, independently of sex. In some studies arterial hypertension as one of the components of the metabolic syndrome, was associated with a higher risk of colorectal, prostate cancer and malignant melanoma. Studies suggest that a higher total serum cholesterol level is linked with higher risk of colorectum, colon, prostate and testicular cancer and lower risk of stomach, liver and hematopoietic and lymphoid tissues cancer. There was positive association between serum triglycerides and esophageal, colorectal, lung, renal, thyroid cancer. Given that hypertension is a common risk factor worldwide and its control remains inadequate, our analysis supports the relevance of public health programs aimed at reducing hypertension to reduce the incidence of a number of cancers including renal cell cancer. Effective cholesterol control may lower the risk of cancer, but further studies with longer follow-up and repeated measurements of cholesterol and other lipids are needed.

The association between serum lipids and colorectal neoplasm: a systemic review and meta-analysis

OBJECTIVE

There have been inconsistent results published regarding the relationship between dyslipidaemia and an increased risk of colorectal neoplasia (CRN), including colorectal adenoma (CRA) and colorectal cancer (CRC). We conducted a meta-analysis to explore the relationship between dyslipidaemia and CRN.

DESIGN

We identified studies by performing a literature search using PubMed, EMBASE and the Science Citation Index through October 2013.

SETTING

We analysed thirty-three independent studies reporting the association between CRN and at least one of the selected lipid components, including total cholesterol (TC), TAG, HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C).

SUBJECTS

CRN cases (n 21 809) were identified.

RESULTS

Overall, people with high levels of serum TAG (risk ratio (RR)=1.08; 95% CI 1.05, 1.12, P<0.00001) and LDL-C (RR=1.07; 95% CI 1.00, 1.14, P=0.04) presented an increased prevalence of CRN. Subgroup analyses revealed that high levels of serum TC (RR=1.04; 95% CI 1.01, 1.09, P=0.02), TAG (RR=1.06; 95% CI 1.03, 1.10, P=0.0009) and LDL-C (RR=1.11; 95% CI 1.04, 1.19, P=0.003) increased the risk of CRA but not of CRC. No association between serum HDL-C and risk for CRN (including CRA and CRC) was observed.

CONCLUSIONS

Both TAG and LDL-C were significantly associated with an increasing prevalence of CRN. High levels of serum TC, TAG and LDL-C were positively associated with CRA but not with CRC. No significant association was observed between levels of serum HDL-C and CRN.

Diet and lifestyle in survivors of colorectal cancer

Much research supports the association between diet and lifestyle in the development of colorectal cancer. Recent studies have demonstrated an association between various energy balance host factors (obesity, physical inactivity, and certain dietary factors) and outcomes. This review summarizes the impact of modifiable lifestyle factors, including prediagnosis and postdiagnosis adiposity, physical activity, and diet, on the prognosis of patients with colorectal cancer. The article focuses on associations of these factors in survivors of stage I to III colorectal cancer, and summarizes the possible mechanisms for the association between modifiable lifestyle factors and the prognosis of patients with colorectal cancer.

Metabolic syndrome and colorectal neoplasms: An ominous association

AIM

To evaluate the association of metabolic syndrome (MS) and colorectal cancer and adenomas in a Western country, where the incidence of MS is over 27%.

METHODS

This was a prospective study between March 2013 and March 2014. MS was diagnosed according to the National Cholesterol Education Program-ATP III. Demographic characteristics, anthropometric measurements, metabolic risk factors, and colonoscopic pathologic findings were assessed in patients with MS (group 1) who underwent routine colonoscopy at our department. This data was compared with consecutive patients without metabolic syndrome (group 2), with no differences regarding sex and age. Patients with incomplete colonoscopy, family history, or past history of colorectal neoplasm were excluded. Informed consent was obtained and the ethics committee approved this study. Statistical analysis was performed using Student's t-test and χ(2) test, with a P value ≤ 0.05 being considered statistically significant.

RESULTS

Of 258 patients, 129 had MS; 51% males; mean-age 67.1 years (50-87). Among the MS group, 94% had high blood pressure, 91% had increased waist circumference, 60% had diabetes, 55% had low high-density lipoprotein cholesterol level, 50% had increased triglyceride level, and 54% were obese [body mass index (BMI) 30 kg/m(2)]. 51% presented 4 criteria of MS. MS was associated with increased prevalence of adenomas (43% vs 25%, P = 0.004) and colorectal cancer (13% vs 5%, P = 0.027), compared with patients without MS. MS was also positively associated with multiple (≥ 3) adenomas (35% vs 9%, P = 0.024) and sessile adenomas (69% vs 53%, P = 0.05). No difference existed between location (P = 0.086), grade of dysplasia (P = 0.196), or size (P = 0.841) of adenomas. In addition, no difference was found between BMI (P = 0.078), smoking (P = 0.146), alcohol consumption (P = 0.231), and the presence of adenomas.

CONCLUSION

MS is positively associated with adenomas and colorectal cancer. However, there is not enough information in western European countries to justify screening in patients with MS. To our knowledge, no previous study has evaluated this association in Portuguese patients.

Association between body mass index and prognosis of colorectal cancer: a meta-analysis of prospective cohort studies

Studies have reported conflicting results on the association between body mass index (BMI) and prognosis of colorectal cancer. Therefore, we have conducted a meta-analysis of prospective studies, which examined the association of pre- and post-diagnostic BMI with colorectal cancer-specific mortality and all-cause mortality in patients with colorectal cancer. We searched Medline and EMBASE database published between 1970 and September 2014. A total of 508 articles were identified, of which 16 prospective cohort studies were included for the current meta-analysis. The analysis included 58,917 patients who were followed up over a period ranging from 4.9 to 20 years (median: 9.9 years). We found that being underweight before cancer diagnosis was associated with increased all-cause mortality (Relative risk [RR]: 1.63, 95% CI: 1.18-2.23, p < 0.01) and being obese (BMI ≥ 30 kg/m(2)) before cancer diagnosis was associated with increased colorectal cancer-specific mortality (RR: 1.22, 95% CI: 1.003-1.35, p < 0.01) and all-cause mortality (RR: 1.25, 95% CI: 1.14-1.36, p < 0.01). On the other hand, being underweight (RR: 1.33, 95% CI: 1.20-1.47, p < 0.01), obese (RR: 1.08, 95% CI: 1.03-1.3, p < 0.01), and class II/III obese (BMI ≥ 35 kg/m(2); RR: 1.13, 95% CI: 1.04-1.23, p < 0.01) after diagnosis were associated with significantly increased all-cause mortality. Being obese prior to diagnosis of colorectal cancer was associated with increased colorectal cancer-specific mortality and all-cause mortality, whereas being obese after diagnosis was associated with increased all-cause mortality. The associations with being underweight may reflect reverse causation. Maintaining a healthy body weight should be discussed with colorectal cancer survivors.

Serum glucose and risk of cancer: a meta-analysis

BACKGROUND

Raised serum glucose has been linked to increased risk of many solid cancers. We performed a meta-analysis to quantify and summarise the evidence for this link.

METHODS

Pubmed and Embase were reviewed, using search terms representing serum glucose and cancer. Inclusion and exclusion criteria focused on epidemiological studies with clear definitions of serum glucose levels, cancer type, as well as well-described statistical methods with sufficient data available. We used 6.1 mmol/L as the cut-off for high glucose, consistent with the WHO definition of metabolic syndrome. Random effects analyses were performed to estimate the pooled relative risk (RR).

RESULTS

Nineteen studies were included in the primary analysis, which showed a pooled RR of 1.32 (95% CI: 1.20 - 1.45). Including only those individuals with fasting glucose measurements did not have a large effect on the pooled RR (1.32 (95% CI: 1.11-1.57). A stratified analysis showed a pooled RR of 1.34 (95% CI: 1.02-1.77) for hormonally driven cancer and 1.21 (95% CI: 1.09-1.36) for cancers thought to be driven by Insulin Growth Factor-1.

CONCLUSION

A positive association between serum glucose and risk of cancer was found. The underlying biological mechanisms remain to be elucidated but our subgroup analyses suggest that the insulin- IGF-1 axis does not fully explain the association. These findings are of public health importance as measures to reduce serum glucose via lifestyle and dietary changes could be implemented in the context of cancer mortality.

Specific metabolic biomarkers as risk and prognostic factors in colorectal cancer

Advances in genomics, molecular pathology and metabolism have generated many candidate biomarkers of colorectal cancer with potential clinical value. Epidemiological and biological studies suggest a role for adiposity, dyslipidaemia, hyperinsulinemia, altered glucose homeostasis, and elevated expression of insulin-like growth factor (IGF) axis members in the risk and prognosis of cancer. This review discusses some recent past and current approaches being taken by researches in obesity and metabolic disorders. The authors describe three main systems as the most studied metabolic candidates of carcinogenesis: dyslipidemias, adipokines and insulin/IGF axis. However, each of these components is unsuccessful in defining the diseases risk and progression, while their co-occurrence increases cancer incidence and mortality in both men and women.

Lipid levels in serum and cancerous tissues of colorectal cancer patients

AIM: To investigate the correlations between lipid metabolism disorder and the occurrence and development of colorectal cancer by monitoring the alterations in lipid levels in cancerous tissue and serum in patients with colorectal cancer.

METHODS: The levels of total and free cholesterol (TCH and FCH), triglycerides (TG), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein- cholesterol (HDL-C), apolipoprotein A1 (ApoA-1) and ApoB in serum of 206 patients with colorectal cancer, 70 patients with benign colorectal disease and 300 healthy participants, and in the cancerous tissue and paracancerous tissue of 152 patients with colorectal cancer were measured with an Olympus 600 auto-biochemical analyzer. The obtained data were statistically analyzed.

RESULTS: Serum FCH level was significantly higher (1.9 ± 0.4 mmol/L vs 1.3 ± 0.3 mmol/L, 1.9 ± 0.4 mmol/L vs 1.2 ± 0.4 mmol/L, P < 0.05), whereas serum levels of TCH, LDL-C, ApoA-I and ApoB were significantly lower in patients with colorectal cancer than in patients with benign colorectal disease and healthy controls. The levels of FCH and TG in cancerous tissue were significantly lower (14.5 ± 9.6 μmol/g vs 19.3 ± 13.9 μmol/g, P < 0.05; 16.3 ± 19.8 μmol/g vs 44.1 ± 38.1 μmol/g, P < 0.05), whereas HDL-C level was significantly higher (7.9 ± 4.5 μmol/g vs 5.7 ± 3.9 μmol/g, P < 0.01) in cancerous tissue than in paracancerous tissue. The levels of TCH and TG in serum and the levels of TCH and HDL-C in cancerous tissue in patients with colorectal cancer were significantly correlated with TNM stage. The levels of TCH and LDL-C in serum were significantly lower, whereas HDL-C level in cancerous tissue was significantly higher in patients with lymph node metastasis than in patients without lymph node metastasis. The levels of TCH, FCH, TG, HDL-C and LDL-C in cancerous tissue were not significantly different from those in paracancerous tissue. The serum levels of FCH and TG were significantly higher, whereas serum HDL-C levels were significantly lower in patients with rectum cancer than in patients with colon cancer.

CONCLUSION: The disordered and abnormally altered levels of lipids in cancerous tissue and serum of patients with colorectal cancer may be correlated with the occurrence and development of colorectal cancer.

[Prevalence and risk factors of colorectal adenoma in 14,932 koreans undergoing screening colonoscopy]

BACKGROUND/AIMS

Current international guidelines recommend colorectal cancer screening for average-risk people over 50 years of age. Accordingly, we aimed to estimate the prevalence of colorectal neoplasms in all age groups and evaluate associated risk factors.

METHODS

Data of 14,932 subjects who underwent colonoscopy from July 2006 to January 2012 at Health Promotion Center, Gangnam Severance Hospital (Seoul, Korea) as part of a health check-up were reviewed retrospectively.

RESULTS

The overall prevalence of colorectal neoplasms and adenoma were 34.6% and 25.3%, respectively. Colorectal adenoma was found in 3.2%, 13.0%, 21.7%, 33.8%, 44.0%, 50.5%, and 54.2% of subjects under 30 years, 30-39 years, 40-49 years, 50-59 years, 60-69 years, 70-79 years, and over 80 years of age (trend p<0.0001). Independent predictors of colorectal adenoma included male gender (OR 2.38, 95% CI 2.084-2.718), positive occult blood (2.266, 1.761-2.917), positive serology of Helicobacter pylori (1.253, 1.114-1.409) and hypertriglyceremia (1.267, 1.065-1.508). Compared to the 30-39 years of age reference group, the ORs for each age group were 0.195 (under 30 years), 1.634 (40-49 years), 2.954 (50-59 years), 5.159 (60-69 years), 5.640 (70-79 years), 11.020 (over 80 years), while the 95% CIs were 0.071-0.536 (under 30 years), 1.340-1.992 (40-49 years), 2.421-3.604 (50-59 years), 4.109-6.476 (60-69 years), 3.822-8.322 (70-79 years), and 2.809-42.234 (over 80 years).

CONCLUSIONS

Colorectal adenoma prevalence increased proportionally with age. Only subjects under the age of 30 years had a definitely lower prevalence of colorectal adenoma. Male gender, positive occult blood, positive serology of H. pylori, and hypertriglyceremia were associated risk factors of colorectal adenoma.

Population-attributable causes of cancer in Korea: obesity and physical inactivity

Background

Changes in lifestyle including obesity epidemic and reduced physical activity influenced greatly to increase the cancer burden in Korea. The purpose of the current study was to perform a systematic assessment of cancers attributable to obesity and physical inactivity in Korea.

Methodology/Principal Findings

Gender- and cancer site-specific population-attributable fractions (PAF) were estimated using the prevalence of overweight and obesity in 1992–1995 from a large-scale prospective cohort study, the prevalence of low physical activity in 1989 from a Korean National Health Examination Survey, and pooled relative risk estimates from Korean epidemiological studies. The overall PAF was then estimated using 2009 national cancer incidence data from the Korea Central Cancer Registry.

Excess body weight was responsible for 1,444 (1.5%) and 2,004 (2.2%) cancer cases among men and women, respectively, in 2009 in Korea. Among men, 6.8% of colorectal, 2.9% of pancreatic, and 16.0% of kidney cancer was attributable to excess body weight. In women, 6.6% of colorectal, 3.9% of pancreatic, 18.7% of kidney, 8.2% of postmenopausal breast, and 32.7% of endometrial cancer was attributable to excess body weight. Low leisure-time physical activity accounted for 8.8% of breast cancer, whereas the PAF for overall cancer was low (0.1% in men, 1.4% in women). Projections suggest that cancers attributable to obesity will increase by 40% in men and 16% in women by 2020.

Conclusions/Significance

With a significantly increasing overweight and physically inactive population, and increasing incidence of breast and colorectal cancers, Korea faces a large cancer burden attributable to these risk factors. Had the obese population of Korea remained stable, a large portion of obesity-related cancers could have been avoided. Efficient cancer prevention programs that aim to reduce obesity- and physical inactivity-related health problems are essential in Korea.

Obesity, metabolic factors, and colorectal adenomas: a retrospective study in a racially diverse New York State Hospital

OBJECTIVE

We studied a racially diverse population and the relationship with colorectal adenomas (CA) further looking for risks related to BMI and metabolic factors.

DESIGNS

Seven hundred seventy-nine patients who underwent screening colonoscopies between 2007 and 2009 meeting exclusion criteria were included. To evaluate the association between race, BMI, and other metabolic factors with having one or more CA detected at colonoscopy, adjusted odds ratios and 95 % CI were estimated using unconditional logistic regression models.

OUTCOMES

CA were detected in 167 out of 779 (21.4 %) patients. Compared to Whites, Hispanics were less likely to have one or more adenomas detected during a screening colonoscopy (OR = 0.52, 95 % CI, 0.31-0.88; p = 0.01). There was no significant statistical difference between Blacks and Whites, or other races and Whites. There was an association between the presence of CA and smoking (OR = 1.57, 95 % CI, 1.02-2.43; p = 0.04).

CONCLUSION

Our results showed that Hispanics were less likely to have an adenoma detected during a screening colonoscopy than Whites. No statistical significant difference was found between patients with metabolic factors and the presence of colorectal adenoma.

Colorectal cancer risk and dyslipidemia: a case-cohort study nested in an Italian multicentre cohort

BACKGROUND

Dyslipidemia is an established risk factor for many diseases, but its effect on colorectal cancer risk is less clear. We investigated the association of colorectal cancer risk with plasma triglycerides, total, HDL, and LDL cholesterol in four Italian EPIC centers.

METHODS

We conducted a case-cohort study on participants recruited to four Italian EPIC centers (Turin, Varese, Naples, and Ragusa; 34,148 subjects). A random subcohort of 850 subjects was obtained and 286 colorectal cancer cases were diagnosed. Triglycerides, total and HDL cholesterol were determined in plasma samples obtained at baseline and stored at -196°C; LDL cholesterol was calculated. Hazard ratios (HR) with 95% confidence intervals (CI), adjusted for potential confounders, were estimated by Cox regression models using the Prentice method.

RESULTS

The highest tertiles of total (HR 1.66, 95%CI 1.12-2.45) and LDL cholesterol (HR 1.87, 95%CI 1.27-2.76) were associated with increased colorectal cancer risk compared to lowest tertiles. Risks were greater for men than women, and for postmenopausal than premenopausal women. Highest tertiles of total and LDL cholesterol were also significantly associated with increased risks of colon cancer, distal colon cancer, and rectal cancer, but not proximal colon cancer.

CONCLUSIONS

Our findings suggest that high levels of total and LDL cholesterol increase colorectal cancer risk, particularly in men and postmenopausal women. However additional studies are needed to clarify the role of plasma lipids in these cancers, particularly in view of the conflicting findings of previous studies.

Obesity and colorectal adenomatous polyps: a cross-sectional study in Korean adults

OBJECTIVE

This study aimed to examine the association between obesity and the risk of colorectal adenomatous polyps.

DESIGN AND METHODS

The design of this study is a cross-sectional study. A total of 1,574 participants (818 males and 756 females), who had undergone colonoscopy for health examinations at the National Cancer Center hospital in South Korea from February to September 2009, were included in the analysis.

RESULTS

The prevalence of colorectal adenomatous polyps was 39.5% in males and 22.6% in females. In multiple logistic regression analysis, obesity (odds ratio [OR] = 1.69, 95% CI = 1.16-2.48) and abdominal obesity (OR = 1.59, 95% CI = 1.13-2.23) were significantly associated with an increased risk of colorectal adenomatous polyps in males, but not in females. In the subgroup analyses by age, obesity (OR = 2.27, 95% CI = 1.32-3.89), and abdominal obesity (OR = 1.76, 95% CI = 1.12-2.76) significantly increased a risk of colorectal adenomatous polyps in males aged <50 years, but not in males aged ≥50 years. However, interaction terms were not significant between obesity and gender (P = 0.397) and between obesity and age (P = 0.531) in the overall analyses.

CONCLUSION

Our findings should be explored in further research.

Association between Obesity, Serum Lipids, and Colorectal Polyps in Old Chinese People

Background. Colorectal cancer mostly arises from the polyps of colon. The aim of our study was to examine the association of body mass index (BMI) and serum lipids with the colorectal polyps in old Chinese people. Methods. The risk of developing colorectal polyps was studied in 244 subjects (212 men and 32 women, 74.63 ± 11.63 years old) who underwent colonoscopy for the first time from January 2008 to July 2012 at the Navy General Hospital, Beijing, China. According to the results of colonoscopy, all the subjects were divided into 112 normal control, 38 right colorectal polyps, 53 left colorectal polyps, and 41 both right and left colorectal polyps groups. The total plasma cholesterol, plasma triglyceride, plasma creatinine concentration, blood urinary nitrogen, and fasting glucose were determined using a multichannel analyzer. Results. There were significant differences among normal control, right colorectal polyps, left colorectal polyps, and both right and left polyps groups, which were the BMI, total cholesterol, triglycerides, creatinine, and urinary nitrogen. In binary logistic regression analysis, there were two risk factors associated with the occurrence of colorectal polyps, which included BMI and systolic blood pressure. Conclusions. Colorectal polyps were significantly associated with increased BMI, total cholesterol, and triglycerides levels.

Metabolic syndrome and colorectal cancer: a cross-sectional survey

INTRODUCTION

There is epidemiological evidence indicating that the metabolic syndrome increases the risk of colorectal cancer. Since there is little information about this issue in Iran, the present study was conducted to evaluate prevalence of metabolic syndrome and its components in patients with colorectal cancer.

MATERIAL AND METHODS

This cross-sectional survey involved 200 patients with a new diagnosis of colorectal cancer. Demographic information of patients was collected through the interview with them. Components of metabolic syndrome including fasting glucose serum, triglyceride, high density lipoprotein, blood pressure and waist circumference were measured for all of the patients.

RESULTS

A total of 72 colorectal cancer patients (36%) met metabolic syndrome criteria with rates of 76% for women and 24% for men. BMI in metabolic syndrome patients was higher than other colorectal cancer patients. Disease history including hypertension, diabetes and cardiovascular disease was most frequent in metabolic syndrome patients. Pathological characteristics of colorectal cancer were not significantly associated with the disease.

CONCLUSION

The findings of present study indicated that the prevalence of metabolic syndrome in CRC patients is relatively high. Therefore, further analytical and multi centric studies are needed to better understand the role of metabolic syndrome in development of CRC in Iran. If this association is confirmed in future studies, metabolic syndrome patients should be considered in CRC screening programs.

The association between obesity and colorectal adenoma: systematic review and meta-analysis

OBJECTIVE

Obesity (body mass index [BMI] ≥30) or overweight (25 ≤ BMI ≤29.9) has been reported to be a risk factor for colorectal adenoma (CRA). However, this association remains controversial. The aim of this study was to determine the association between overweight or obesity and CRA.

DESIGN

Systematic review and meta-analysis were conducted using English language studies from EMBASE and MEDLINE. Appropriate observational studies were selected from 1966 through September 2011. Adjusted odds ratios (ORs) were extracted from each study.

RESULTS

One hundred and seventy full-text articles were reviewed after retrieving 1199 initial search results. Five studies in which BMI was treated as continuous variable, three studies in which BMI was dichotomized using a cutoff value of 25, three studies in which BMI was categorized into three groups using values of 22 and 25, and eight studies in which BMI was categorized into three groups using values of 25 and 30 were selected. Regarding risk for CRA, pooled OR [95% CI] of one increment increase in BMI was 1.02 [0.99-1.03] (random effects model [REM]), while that of BMI ≥ 25 was 1.27 [1.15-1.4] (Fixed effects model). Pooled ORs [95% CI] of BMI ≥ 22 and BMI ≥ 25 was 1.42 [0.69-2.9] [REM] and 1.81 [0.36-9.1] [REM], respectively. Pooled ORs [95% CI] of BMI ≥ 25 and BMI ≥ 30 was 1.16 [0.98-1.38] [REM] and 1.47 [1.18-1.83] [REM], respectively.

CONCLUSION

Obesity and overweight are significant risk factors for CRA. However, there are no data showing linear relationship between increasing BMI and CRA.

Serum lipid profiles and cancer risk in the context of obesity: four meta-analyses

The objective here was to summarize the evidence for, and quantify the link between, serum markers of lipid metabolism and risk of obesity-related cancers. PubMed and Embase were searched using predefined inclusion criteria to conduct meta-analyses on the association between serum levels of TG, TC, HDL, ApoA-I, and risk of 11 obesity-related cancers. Pooled relative risks (RRs) and 95% confidence intervals were estimated using random-effects analyses. 28 studies were included. Associations between abnormal lipid components and risk of obesity-related cancers when using clinical cutpoints (TC ≥ 6.50; TG ≥ 1.71; HDL ≤ 1.03; ApoA-I ≤ 1.05 mmol/L) were apparent in all models. RRs were 1.18 (95% CI: 1.08–1.29) for TC, 1.20 (1.07–1.35) for TG, 1.15 (1.01–1.32) for HDL, and 1.42 (1.17–1.74) for ApoA-I. High levels of TC and TG, as well as low levels of HDL and ApoA-I, were consistently associated with increased risk of obesity-related cancers. The modest RRs suggest serum lipids to be associated with the risk of cancer, but indicate it is likely that other markers of the metabolism and/or lifestyle factors may also be involved. Future intervention studies involving lifestyle modification would provide insight into the potential biological role of lipid metabolism in tumorigenesis.

Obesity and risk of colorectal cancer: a systematic review of prospective studies

Background

Mounting evidence indicates that obesity may be associated with the risk of colorectal cancer (CRC). To conduct a systematic review of prospective studies assessing the association of obesity with the risk of CRC using meta-analysis.

Methodology/Principal Findings

Relevant studies were identified by a search of MEDLINE and EMBASE databases before January 2012, with no restrictions. We also reviewed reference lists from retrieved articles. We included prospective studies that reported relative risk (RR) estimates with 95% confidence intervals (CIs) for the association between general obesity [measured using body mass index (BMI)] or central obesity [measured using waist circumference (WC)] and the risk of colorectal, colon, or rectal cancer. Approximately 9, 000, 000 participants from several countries were included in this analysis. 41 studies on general obesity and 13 studies on central obesity were included in the meta-analysis. The pooled RRs of CRC for the obese vs. normal category of BMI were 1.334 (95% CI, 1.253–1.420), and the highest vs. lowest category of WC were 1.455 (95% CI, 1.327–1.596). There was heterogeneity among studies of BMI (P<0.001) but not among studies of WC (P = 0.323).

Conclusions

Both of general and central obesity were positively associated with the risk of CRC in this meta-analysis.

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.

Body mass index increases risk for colorectal adenomas based on meta-analysis

BACKGROUND & AIMS

There have been inconsistent results published about the relationship between excess body weight, expressed as increased body mass index (BMI), and risk of colorectal adenoma (CRA). We conducted a meta-analysis to explore this relationship. We focused on whether the relationship varied based on the sex of the study subjects, study design, features of the polyps, or potential confounders, including alcohol use, nonsteroidal anti-inflammatory drug use, smoking, and exercise.

METHODS

We identified studies by performing a literature search of Medline, EMBASE, and ISI Web of Science through July 31, 2011, and by searching the reference lists of pertinent articles. We analyzed 36 independent studies, which included 29,860 incident cases of CRA. Summary relative risks with their 95% confidence intervals (CIs) were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and I(2) analyses.

RESULTS

Overall, a 5-unit increase in BMI (calculated as kg/m(2)) increased the risk for CRA (summary relative risk = 1.19; 95% CI: 1.13-1.26), although there was a high level of heterogeneity among studies (P(heterogeneity) < .001; I(2) = 76.8%). Subgroup analyses revealed that the increased risk of CRA in obese individuals was independent of race, geographic location, study design, sex, adenoma progression, and confounders. The association between increased BMI and risk for CRA was stronger for colon than rectal adenoma.

CONCLUSIONS

Based on a meta-analysis, increased BMI increases the risk for colon but not rectal adenoma. Unlike colorectal cancer, there is no sex difference in the relationship between increased BMI and risk of CRA.

Advances in understanding the relationship between lipid metabolism and colorectal carcinoma

In recent years, the morbidity and mortality of colorectal carcinoma (CRC) have been increasing and it has become a serious threat to human health. In the research of the development of CRC, more and more researchers are concerned about the relationship between lipid metabolism and CRC. High-fat diets are more likely to cause CRC. Different types of lipids may play an opposite role in the formation and development of CRC. There are various hypotheses explaining the effect of lipid metabolism on the pathogenesis of CRC, and further studies are needed to confirm them. Elucidation of the relationship between lipid metabolism and CRC will be beneficial to the diagnosis and therapy of this malignancy.

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.

The synchronous prevalence of colorectal neoplasms in patients with stomach cancer

Purpose

The association between stomach cancer and colorectal cancer is controversial. The purpose of this study was to determine the synchronous prevalence of colorectal neoplasms in patients with stomach cancer.

Methods

A total of 123 patients with stomach cancer (86 male) and 246 consecutive, age- and sex-matched persons without stomach cancer were analyzed from July 2005 to June 2010. All of them underwent colonoscopy within 6 months after undergoing gastroscopy.

Results

The prevalence of colorectal neoplasms was significantly higher in the stomach cancer group (35.8%) than in the control group (17.9%) (P < 0.001). Colorectal neoplasms were more prevalent in the patients with stomach cancer (odds ratio [OR], 3.10; 95% confidence interval [CI], 1.71 to 5.63). In particular, the difference in the prevalence of colorectal neoplasms was more prominent in the patients above 50 years old (OR, 3.54; 95% CI, 1.80 to 6.98).

Conclusion

The results showed that the synchronous prevalence of colorectal neoplasms was higher in patients with stomach cancer than in those without stomach cancer. Therefore, patients with stomach cancer should be regarded as a high-risk group for colorectal neoplasms, and colonoscopy should be recommended for screening.