Metabolic Syndrome Components and the Risk of Colorectal Cancer: A Population-Based Prospective Study in Chinese Men

Transitions in metabolic syndrome and metabolic obesity status over time and risk of urologic cancer: A prospective cohort study

BACKGROUND AND AIMS

The effects of metabolic obesity (MO) phenotypes status and their dynamic changes on urologic cancer (UC) is ignored. We aimed to investigate the association between metabolic syndrome (MetS) and MO status at baseline, their dynamic changes and UC risk.

METHODS

This paper studied 97,897 subjects who were free of cancers at baseline (2006-2007). Individuals were classified into four MO phenotypes by MetS and obesity at baseline. Transitions in MetS and MO status from 2006-2007 to 2008-2009 were considered. The hazard ratios (HRs) and 95% confidence intervals (CIs) for UC were assessed by multifactorial Cox proportional risk regression models. The main limitations of this study are as follows: the ratio of men to women in the cohort is unbalanced; the impacts of MetS and MO on each cancer type (kidney cancer, prostate cancer, bladder cancer) have not been analyzed separately; the transition intervals of MetS and MO phenotypes are relatively short.

RESULTS

From baseline (2006-2007) survey to December 31, 2020, during a median follow-up of 14.02 years, 554 cases of UC were diagnosed. Participants with MetS [HRs (95% CI) = 1.26 (1.06-1.49)] and metabolically unhealthy obesity (MUO) [HRs (95% CI) = 1.49 (1.17-1.89)] had significantly higher risk of UC than those with non-MetS and metabolically healthy normal weight (MHN). Transitions in MetS and MO phenotypes over time were studied. Compared with non-MetS to non-MetS, the risks for UC in MetS to MetS [HRs (95% CI) = 1.45 (1.11-1.88)] was increased. Compared with MHN to MHN, both MUO to metabolically healthy obesity (MHO) [HRs (95% CI) = 2.65 (1.43-4.92)] and MUO to MUO [HRs (95% CI) = 1.60 (1.06-2.42)] had significantly higher UC risk.

CONCLUSIONS

MetS and MUO increased the UC risk at baseline. Transitions of MetS to MetS, MUO to MUO and even MUO to MHO over time significantly increased the risk of UC development.

Association between body mass index combined with high-sensitivity C-reactive protein and the risk of postmenopausal breast cancer: A prospective cohort study

The present study aimed to assess the risk of postmenopausal breast cancer in women based on a combination of body mass index (BMI) and high-sensitivity C-reactive protein (hs-CRP) levels. A total of 20,400 participants were investigated as part of the 'Kailuan Study' clinical trial. Participants were classified into four groups based on BMI (BMI ≥24 or <24 kg/m2) and hs-CRP level (hs-CRP ≥3 or <3 mg/l). Cox proportional hazards models were used to evaluate the association between the combination of BMI and hs-CRP and the risk of postmenopausal breast cancer. A total of 19,540 participants met the inclusion criteria. The median follow-up time was 14.97 years, with a cumulative follow-up period of 283,599.43 person-years. Among the participants, 269 individuals were diagnosed with postmenopausal breast cancer. Individuals with a high BMI (BMI ≥24 kg/m2) and a high hs-CRP level (hs-CRP ≥3 mg/) had a greater risk of postmenopausal breast cancer compared with individuals with a low BMI (BMI <24 kg/m2) and a low hs-CRP level (<3 mg/l) (hazard ratio, 1.75; 95% confidence interval, 1.25-2.47). The sensitivity analysis showed findings consistent with the primary results. In conclusion, the combination of high BMI and high hs-CRP level is associated with an increased risk of postmenopausal breast cancer. The present study is part of the Kailuan Study. Trial registration number: ChiCTRTNCR11001489 (Chinese Clinical Trial Registry, https://www.chictr.org.cn/showproj.html?proj=8050). Date of registration: 19/07/2015.

Associations between blood glucose and early- and late-onset colorectal cancer: evidence from two prospective cohorts and Mendelian randomization analyses

Background

The incidence of early-onset colorectal cancer (EOCRC), which exhibits differential clinical, pathological, and molecular features compared to late-onset CRC (LOCRC), is rising globally. The potential differential effects of blood glucose on EOCRC compared to LOCRC have not been investigated.

Methods

This study analyzed 374,568 participants from the UK Biobank cohort and 172,809 participants from the Kailuan cohort. The linear associations between blood glucose and EOCRC/LOCRC were estimated using Cox regression models. Restricted cubic spline (RCS) analysis and non-linear Mendelian randomization (MR) analysis using a 70-SNPs genetic instrument for fasting glucose were used to explore the potential non-linear associations.

Results

Participants in the highest quintile of blood glucose had higher overall CRC risk compared to the lowest quintile (HR = 1.10 in the UK Biobank cohort, 95% CI: 1.01-1.21, P-trend = 0.012; HR = 1.23 in the Kailuan cohort, 95% CI: 1.01-1.51, P-trend = 0.036). Elevated glucose (>7.0 mmol/L) was more strongly associated with increased risk of EOCRC (HR = 1.61, 95% CI: 1.07-2.44) than with LOCRC (HR = 1.14, 95% CI: 1.02-1.27) in the UK Biobank cohort (P-heterogeneity = 0.014). Elevated glucose (>7.0 mmol/L) was associated with increased risk of LOCRC (HR = 1.25, 95% CI: 1.04-1.65) in the Kailuan cohort as well. There was no evidence for non-linear associations between blood glucose and risks of EOCRC/LOCRC.

Conclusions

This study showed a positive association between blood glucose and CRC risk in a dose-response manner, particularly for EOCRC, suggesting that tighter glucose control should be a priority for younger age groups.

Exploring the association between metabolic syndrome, its components and subsequent cancer incidence: A cohort study in Catalonia

BACKGROUND

Metabolic syndrome (MS) has emerged as a significant global health concern. The relationship between MS and the risk of cancer doesn't seem clear, whether examining by components or in combination. The objective of this study is to examine the relationship between MS, its components, and the overall risk of cancer, including the risk of 13 specific cancer types.

METHODS

We included 3,918,781 individuals aged 40 years or older sourced from the SIDIAP database between 2008 and 2017. Cox models were employed with MS components and their combinations. A subsample was created using a matched cohort (by age and sex). Incidence curves were computed to determine the time elapsed between the date of having 1-5 MS components and cancer incidence, compared to matched participants with no MS components, which showed that individuals who had one MS component experienced a greater incidence of cancer over 5 and 10 years than individuals with no MS, and the incidence rose with an increase in the number of MS components.

RESULTS

Individuals exposed to MS components were diagnosed with cancer earlier than those who were not exposed to them. In the Cox model, HDL (HR 1.46, 95% CI: 1.41-1.52) and Glycemia (HR 1.40, 95% CI: 1.37-1.44) were the individual combinations with the highest risk of overall cancer. In combinations with two components, the highest HR was HDL+Glycemia (HR 1.52, 95% CI: 1.45-1.59) and Glycemia+HBP (HR 1.48, 95% CI: 1.45-1.50). In combinations with three components, the highest HR was HDL+Glycemia+HBP (HR 1.58, 95% CI: 1.55-1.62).

CONCLUSION

In summary, having one or more MS components raises the risk of developing at least 11 cancer types and these risk differ according to type of component included. Some sex differences are also observed. Our findings suggest that implementing prevention measures aimed at specific MS components may lower the risk of various cancer types.

The Persistence of Hypertriglyceridemia and the Risk of Early Onset Colorectal Cancer According to Tumor Subsites: A Nationwide Population-Based Study

PURPOSE

The incidence of early-onset colorectal cancer (EoCRC) is increasing worldwide. The association between hypertriglyceridemia (HTG) and EoCRC risk remains unclear.

MATERIALS AND METHODS

We conducted a nationwide cohort study of 3,340,635 individuals aged 20-49 years who underwent health checkups between 2009 and 2011 under the Korean National Health Insurance Service. HTG was defined as serum triglyceride (TG) level ≥ 150 mg/dL. According to the change in TG status, participants were categorized into persistent normotriglyceridemia (NTG; group 1), NTG to HTG (group 2), HTG to NTG (group 3), and persistent HTG (group 4) groups. The EoCRC incidence was followed up until 2019.

RESULTS

In total, 7,492 EoCRC cases developed after a mean of 6.05 years of follow-up. Group 4 had the highest risk of EoCRC (adjusted hazard ratio [aHR], 1.097; 95% confidence interval [CI], 1.025 to 1.174). While the risk of rectal cancer was significantly increased in groups 3 and 4 (aHR [95% CI], 1.236 [1.076 to 1.419] and 1.175 [1.042-1.325], respectively), no significant risk differences were observed in right colon cancer. In group 4, male sex and diabetes were associated with a further increased risk of EoCRC (aHR [95% CI], 1.149 [1.082 to 1.221] and 1.409 [1.169 to 1.699], respectively). In addition, there was a dose-response relationship between serum TG levels and the risk of EoCRC (p for trends < 0.0001).

CONCLUSION

Persistent HTG increased the risk of EoCRC, which was significantly higher only for rectal cancer and marginally higher for other colonic subsites.

Association between insulin resistance related indicators with the prognosis of patients with colorectal cancer

BACKGROUND

The progression of colorectal cancer (CRC) has been linked to metabolism alteration. Because insulin resistance (IR) is the basic mechanism of metabolism alteration, IR related indicators are considered to be associated with prognostic of CRC. In this study, we compared the prognostic values of common IR related indicators for CRC and selected the best one. Moreover, we explored the association between that indicator and CRC prognosis and possible interactive covariates.

METHODS

Medical records of patients with CRC (n = 1765) were retrieved from the Investigation on Nutrition Status and Clinical Outcome of Common Cancers (INSCOC) study. We compared the prognostic values of IR related indicators and select the best one using concordance index (C-index) and area under curve (AUC). Using Cox proportional hazard regression models, we evaluated the association between that indicator and CRC prognosis. Interaction tests were performed to evaluate possible interactions among covariates and the IR related indicator.

RESULTS

Results of C-index and AUC indicated that the ratio of low-density lipoprotein-to-high-density lipoprotein (LHR) showed the highest ability to predict the prognosis of patients with CRC. LHR independently predicted CRC prognosis [hazard ratio (HR) = 1.14; 95 % confidence interval (CI) = 1.05-1.22; P = 0.001]. The interactions between LHR, and age (<65 vs. ≥65; P for interaction = 0.001) or neutrocyte-to-lymphocyte ratio (NLR) (<3 vs. ≥3; P for interaction = 0.055) were also observed.

CONCLUSION

LHR was found to be the best IR related indicators to predict prognosis of CRC, and it was negatively correlated with the prognosis of patients with CRC. NLR and aging might interact with LHR.

[Metabolic syndrome and gastrointestinal cancer screening]

Cancer has become a leading cause of death among patients with metabolic syndrome (MetS). The more components of MetS a patient has, the higher his cancer risk is. MetS is causally associated with colorectal, pancreatic, gallbladder, biliary, hepatocellular, gastric and esophageal adenocarcinomas. MetS increases cancer mortality up to 2.4-fold. Intentional long-term weight loss reduces the excess cancer risk of obese MetS-patients. Preventing and treating the MetS together with GI cancer screening is effective and decreases the burden of GI cancer mortality significantly.

Association of metabolic syndrome and its components with the risk of urologic cancers: a prospective cohort study

OBJECTIVE

To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing urologic cancers.

METHODS

This study included 101,510 observation subjects from May 2006 to December 2007. The subjects received questionnaires and were subjected to clinical and laboratory examinations to collect data on baseline population characteristics, waist circumference (WC), blood pressure (BP), blood glucose, blood lipids, lifestyle, and past disease history. Finally, follow-up was conducted from the date of recruitment to December 31, 2019. Cox proportional hazards modelling was applied to analyze the association between MetS and its components and the risk of developing urologic cancers.

RESULTS

A total of 97,975 observation subjects met the inclusion criteria. The cumulative follow-up period included 1,209,178.65 person-years, and the median follow-up time was 13.03 years. During the follow-up period, 485 cases of urologic cancers (165 cases of kidney cancer, 134 cases of prostate cancer, 158 cases of bladder cancer, and 28 cases of other urologic cancers) were diagnosed. The log-rank test results for the cumulative incidences of urologic cancer, kidney cancer, and prostate cancer indicated significant (P < 0.01) differences between the MetS and non-MetS groups (0.70% vs. 0.48%, 0.27% vs. 0.15%, and 0.22% vs. 0.13%, respectively). Compared to the non-MetS group, the risk of developing urologic [HR (95% CI) = 1.29 (1.08-1.55)], kidney [HR (95% CI) = 1.74 (1.28-2.37)], and prostate [HR (95% CI) = 1.47 (1.04-2.07)] cancers was significantly higher in the MetS group. In the MetS group, elevated BP increased the risk of developing of urologic cancer [HRs (95% CI) = 1.35 (1.10-1.66)] and kidney cancer [HR (95% CI) = 1.74 (1.21-2.51)], while central obesity increased the risk of developing prostate cancer [HR (95% CI) = 1.68 (1.18-2.40)].

CONCLUSIONS

MetS increased the risk of developing urologic, kidney, and prostate cancers but had no association with the development of bladder cancer.

Association of education level with the risk of female breast cancer: a prospective cohort study

BACKGROUND

Breast cancer is a serious threat to female health, and its incidence varies with education level (EL). In the present study, the association between EL and the risk of developing female breast cancer was investigated.

METHODS

From May 2006 to December 2007, 20,400 observation subjects in Kailuan Cohort received questionnaires and were subjected to clinical examinations for data collection on baseline population characteristics, height, weight, lifestyle and past disease history. Then, these participants were followed up with from the date of recruitment to December 31, 2019. Cox proportional risk regression models were used to analyse the association between EL and the risk of developing female breast cancer.

RESULTS

The cumulative follow-up period of 20,129 observation subjects that meet the inclusion criteria of this study was 254,386.72 person-years, and the median follow-up time was 12.96 years. During the follow-up period, 279 cases of breast cancer were diagnosed. In comparison with the low EL group, the risk of developing breast cancer was significantly higher in the medium (hazard ratio [HR] (95% confidence interval [CI]) = 2.23 (1.12-4.64)] and high [HRs (95% CI) = 2.52 (1.12-5.70)] EL group.

CONCLUSION

An increased risk of breast cancer was associated with a higher EL, and some certain factors, such as alcohol use and hormone therapy, may play a mediating role.

Association of metabolic syndrome and its components with the risk of kidney cancer: A cohort-based case-control study

BACKGROUND

Metabolic syndrome increases the risk of developing several types of cancer in humans; however, its effect on the development of kidney cancer is not uniform.

OBJECTIVE

To investigate the association between metabolic syndrome (MetS) and its components and the risk of developing kidney cancer.

METHODS

We conducted a cohort-based case-control study. The case group included 217 patients with new kidney cancer in the Kailuan cohort. A total of 868 subjects who were matched for age and sex with those in the case group age (± 1 year) at 1:4 as the control group were selected from baseline survey participants without malignant tumours at the same time as the case group. Biennial baseline survey data of the cases and controls were collected, and the baseline data nearest to the onset time of cases were used for statistical analyses. Logistic proportional risk regression models were used to analyse the association between MetS and its components and the risk of developing kidney cancer.

RESULTS

The proportion of MetS patients in the case group was significantly higher than that in the control group (P< 0.01). The risk of developing kidney cancer was significantly higher in the MetS group than in the non-MetS group [odds ratio (OR) (95% confidence interval, CI) = 1.63 (1.20-2.21)], and the risk of kidney cancer increased as the number of MetS components increased compared with subjects without any MetS components (p𝑡𝑟𝑒𝑛𝑑< 0.01). Elevated blood pressure and low high-density lipoprotein cholesterol levels were associated with the risk of kidney cancer [OR (95% CI) = 1.49 (1.02-2.17) and 1.55 (1.13-2.13), respectively].

CONCLUSION

Our findings suggest that the risk of developing kidney cancer is correlated with MetS.

Association between metabolic syndrome and colorectal cancer incidence and all-cause mortality: a hospital-based observational study

Background

Metabolic syndrome (MetS) is a worldwide pandemic and complex disorder associated with colorectal cancer (CRC). This study aims to identify the influence of number of MetS components on CRC incidence and mortality, using a national, longitudinal dataset of hospital care in Taiwan.

Methods

Patient data from the Taiwan National Health Insurance Research Database (NHIRD) from 2001 to 2008 were extracted. Individuals with at least one inpatient diagnosis or 2 outpatient visits with any MetS component found within one year were identified and included. Subjects died within 12 months after the presence of MetS components or had any prior cancer were excluded. The study cohort were then divided into two groups: subjects who had more (i.e., 3 to 4) MetS components and those who had fewer (i.e., 1 to 2) MetS components. An 2:1 propensity score (PS) matching were performed to balance the baseline characteristics between the groups. Cox regression analyses were conducted to compare the CRC incidence and all-cause mortality at follow-up between subjects with more MetS components versus fewer components.

Results

After matching, a total of 119,843 subjects (78,274 with 1–2 and 41,569 with 3–4 MetS components) were analyzed. After adjusting for confounders, subjects with 3–4 MetS components had a significantly higher risk of CRC [adjusted hazard ratio (aHR), 1.28; 95% confidence interval (CI), 1.15–1.43, p < 0.001) and all-cause mortality (aHR, 1.13; 95% CI, 1.08–1.17, p < 0.001) than those with only 1–2 MetS components. In stratified analyses, the greatest increased risk of CRC incidence that 3–4 MetS components posed as compared to 1–2 MetS components was seen in subjects without CHD history (aHR, 1.41, 95% CI, 1.23–1.62, p < 0.001). In addition, 3–4 MetS components (vs. 1–2) led to greater all-cause mortality among the subjects < 65y, both genders, with or without CHD, subjects without CKD hisotry, both aspirin users and non-users, users of nonsteroidal anti-inflammatory drugs (NSAIDs), and users of statin.

Conclusion

Compared with 1–2 components, subjects with 3–4 MetS components are at greater risk of CRC and death at follow-up. This study also demonstrates the risks for CRC and all-cause mortality in certain subgroups of individuals with 3–4 MetS components compared to 1–2 components. These findings may help clinicians on the CRC risk stratification according to individuals’ characteristics, as well as to optimize the strategy of MetS surveillance and control in order to prevent CRC.

The Effect of Metabolic Syndrome on Colorectal Cancer Prognosis after Primary Surgery

PURPOSE

The purpose of this study was to explore whether metabolic syndrome (MetS) affects the prognosis of colorectal cancer (CRC) patients after primary surgery and to analyze the effect of the specific components of MetS on CRC prognosis.

METHODS

The PubMed, Embase and Cochrane Library databases were searched from inception to July 29, 2021. Overall survival (OS) and disease-free survival (DFS) were compared between the MetS group and the non-MetS group.

RESULTS

The studies included in the meta-analysis included 4773 patients. All seven studies compared OS between the two groups, and after pooling all hazard ratios (HRs), no significant difference was found between the MetS group and the non-MetS group (HR = 1.17, 95% CI = 0.91 to 1.49, P = 0.21). Four studies compared DFS between the MetS group and the non-MetS group after pooling all the HRs, and there was no difference between the MetS group and the non-MetS group (HR = 1.05, 95% CI = 0.74 to 1.49, P = 0.21). Among the specific components of MetS, high fasting plasma glucose levels (HR = 1.25, 95% CI = 1.00 to 1.58, P = 0.05) had a marginally significant association with poor OS.

CONCLUSION

MetS may not affect the prognosis of CRC after primary surgery. However, high fasting plasma glucose levels might contribute to poor OS.

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.

Diabetes and Colorectal Cancer Risk: A New Look at Molecular Mechanisms and Potential Role of Novel Antidiabetic Agents

Epidemiological data have demonstrated a significant association between the presence of type 2 diabetes mellitus (T2DM) and the development of colorectal cancer (CRC). Chronic hyperglycemia, insulin resistance, oxidative stress, and inflammation, the processes inherent to T2DM, also play active roles in the onset and progression of CRC. Recently, small dense low-density lipoprotein (LDL) particles, a typical characteristic of diabetic dyslipidemia, emerged as another possible underlying link between T2DM and CRC. Growing evidence suggests that antidiabetic medications may have beneficial effects in CRC prevention. According to findings from a limited number of preclinical and clinical studies, glucagon-like peptide-1 receptor agonists (GLP-1RAs) could be a promising strategy in reducing the incidence of CRC in patients with diabetes. However, available findings are inconclusive, and further studies are required. In this review, novel evidence on molecular mechanisms linking T2DM with CRC development, progression, and survival will be discussed. In addition, the potential role of GLP-1RAs therapies in CRC prevention will also be evaluated.

Association between metabolic syndrome and its components and incident colorectal cancer in a prospective cohort study

BACKGROUND

Metabolic syndrome (MetS) has been identified as a contributor to cancer development. However, reports concerning the association between MetS and colorectal cancer (CRC) have been inconsistent. This study investigated whether MetS, its components, and the number of components increase the risk of CRC.

METHODS

This was a prospective cohort study of 41,837 participants recruited from August 2002 to December 2014 from the National Cancer Center in South Korea. The participants were followed until December 2017 to identify incident CRC cases. The participants underwent laboratory tests at the baseline. Additionally, a self-administered questionnaire collected information concerning lifestyle and general characteristics at the baseline. A Cox proportional hazards model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) to explore the association between MetS and its components and CRC risk after adjustments for confounding variables.

RESULTS

In total, 128 incident CRC cases were identified during the follow-up period. An increased CRC risk was found among participants with MetS (HR, 1.63; 95% CI, 1.08-2.44). Additionally, elevated blood pressure (HR, 1.50; 95% CI, 1.05-2.15) and a high fasting glucose level (HR, 1.80; 95% CI, 1.23-2.63) were associated with an elevated risk of CRC. Notably, an increased risk was identified among participants with abdominal obesity coexisting with another component of MetS.

CONCLUSIONS

These results suggest that MetS is a risk factor for CRC. Greater emphasis should be placed on the importance of CRC screening among individuals with abdominal obesity coexisting with another component of MetS.

LAY SUMMARY

Colorectal cancer (CRC) ranks as the third most common cancer type in terms of incidence. Metabolic syndrome (MetS) has been identified as a contributor to cancer development. However, the association between MetS and CRC remains controversial because of a lack of consistent findings in previous studies. In this study, the National Cholesterol Education Program's Adult Treatment Panel III guidelines are used for the diagnosis of MetS. MetS is found to be a predictor of CRC. Additionally, the importance of CRC screening among individuals with 2 components of MetS should be emphasized.

Metabolic syndrome and the risk of colorectal cancer: a systematic review and meta-analysis

PURPOSE

Observational studies have reported an association between metabolic syndrome (MetS) and colorectal cancer risk with inconsistent risk estimates. We conducted this meta-analysis to evaluate the risk of colorectal cancer in individuals with MetS.

METHODS

PubMed, Embase, and Web of Science were searched for related studies from database inception to 21 January 2021. Risk estimates for colorectal cancer were extracted from individual articles and pooled using a fixed-effect or random-effect model according to the heterogeneity.

RESULTS

MetS was significantly associated with a higher risk of colorectal cancer in both sexes (relative risk [RR] 1.36, 95% confidence interval [CI] 1.26-1.47, P < 0.001), men (RR 1.33, 95% CI 1.21-1.47, P < 0.001), and women (RR 1.34, 95% CI 1.19-1.52, P < 0.001). The risk of colorectal cancer seemed to increase as the number of MetS components rose. Moreover, the high body mass index (BMI)/waist circumference (WC) and hyperglycemia were all significantly associated with a higher risk of colorectal cancer (RR 1.28 [1.20-1.37] and 1.31 [1.14-1.50] in both sexes, RR 1.31 [1.19-1.45] and 1.23 [1.03-1.46] in men, and RR 1.22 [1.02-1.46] and 1.63 [1.16-2.28] in women, respectively).

CONCLUSIONS

MetS was significantly associated with a higher risk of colorectal cancer. The high BMI/WC or hyperglycemia might largely account for this association. Further analysis suggested that, as the number of MetS components increased, the risk of colorectal cancer rose.

Association between cardiovascular risk factors and colorectal cancer: A systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Emerging data have suggested colorectal cancer (CRC) often coexists with cardiovascular diseases, but whether cardiovascular risk factors play a role in CRC remains unclear. We performed a systematic review and meta-analysis to better illustrate the associations between cardiovascular risk factors and CRC.

METHODS

We searched EMBASE, MEDLINE and Web of Science databases from inception up to June 14, 2020. Prospective cohort studies were included if they evaluated the association between at least one of cardiovascular risk factors and CRC incidence, containing sufficient data to obtain relative risk (RR) and 95% confidence interval (CI). We performed separate meta-analyses for each cardiovascular risk factor using random-effect model. PROSPERO registration number: CRD42020175537.

FINDINGS

Data from 84 studies, reporting 52, 348, 827 individuals and 384, 973 incident cases were included in the analysis. Overall, the risk of CRC was 1.31(95% CI, 1.21-1.42) for obesity, 1.14 (95% CI, 1.09-1.20) for per 5 kg/m2 increase in body mass index, 1.18 (95% CI, 1.14-1.23) for former smoker, 1.20 (95% CI, 1.11-1.30) for current smoker, 1.25 (95% CI, 1.16-1.35) for diabetes, 1.07 (95% CI, 1.02-1.12) for hypertension. The summary RRs of CRC for the highest versus lowest quartiles of total cholesterol, triglyceride, low-density lipoprotein were 1.12 (95% CI, 1.03-1.22), 1.18 (95% CI, 1.04-1.35), 0.85 (95% CI, 0.62-1.17) respectively and the pooled RR for the lowest versus highest quartile of high-density lipoprotein was 1.14 (95% CI, 1.02-1.28).

INTERPRETATION

Unfavorable cardiovascular risk factors are associated with increased risk of CRC, which may provide novel insight into the screening strategies of CRC in patient with these risk factors.

The association of Metabolic Syndrome and its Components with the Incidence and Survival of Colorectal Cancer: A Systematic Review and Meta-analysis

Background: This meta-analysis was aimed to quantitatively assess the associations of metabolic syndrome (MetS) and its components with colorectal cancer (CRC). Methods: PubMed, EMBASE and Web of Science databases were systematically searched for eligible studies. A total of 18 studies for CRC incidence and 12 studies for CRC mortality were identified. Results: MetS was associated with an increased risk of CRC incidence and mortality in male (RR: 1.28, 95 % CI 1.16-1.39, and 1.24, 1.18-1.31, respectively) and correlated with an increased risk of CRC incidence in female (RR: 1.21, 1.13-1.30), but not with CRC mortality in female. MetS increased the risk of cancer-specific mortality (RR: 1.72, 1.03-2.42), but not overall mortality. The risk estimates of CRC incidence changed little depending on age, sex, cancer site, the type of studies, ethnicity, publication year, or definition of MetS. As for CRC mortality, further stratified analyses indicated statistical significance in studies with assessing cancer-specific survival outcome, in male, a cohort design, ethnicity of non-Chinese or with definition of MetS as ≥ 3 metabolic abnormalities. Obesity and hyperglycemia are risk factors of CRC incidence in both male and female. Only dysglycemia is the risk factor for CRC mortality. Conclusions: MetS is associated with an increased risk of CRC incidence and cancer-specific mortality, but not overall mortality. In addition, MetS may increase the CRC mortality in male rather than in female. However, since most of the studies on CRC mortality were conducted in Chinese, further studies are needed to clarify this connection.