The Association between Obesity and Colorectal Cancer

Mendelian randomization unraveled: gender-specific insights into obesity-related phenotypes and colorectal cancer susceptibility

Objective

Evidence has been increasingly pointing towards a potential link between phenotypes related to obesity and the incidence of colorectal cancer. However, confirming this as a direct causal connection remains elusive. This investigation aims to elucidate the causative links between obesity-associated phenotypes and the incidence of colorectal cancer.

Methods

Employing the Two Sample Mendelian Randomization (TwoSampleMR) R package, analyses were conducted using Mendelian randomization (MR) to discern potential causative links between obesity categories sourced from both the Institute for Education and University (IEU) Open GWAS Project and Zenodo, and colorectal tumors (data obtained from IEU Open GWAS and FinnGen). For primary evaluations, the study utilized the Wald ratio and the Inverse Variance Weighting (IVW) methods, while the MR-Egger approach was integrated for sensitivity assessment. Bidirectional Mendelian Randomization (Bidirectional MR), as well as Linkage Disequilibrium (LD) Score Regression with well-imputed HapMap3 single nucleotide polymorphisms (SNPs), were additionally executed. Sensitivity assessments entailed IVW, MR-Egger methodologies to assess heterogeneity and pleiotropy, along with a leave-one-out strategy. Instrumental variables were chosen judiciously based on predetermined P-value thresholds and F-statistics.

Results

Results from MR evaluations did not identify a clear causative link between BMI and colorectal malignancy. Conversely, both measures of obesity, the Waist-Hip Ratio (WHR) and its adjusted form for BMI (WHRadjBMI), displayed a connection to increased risk of colorectal cancer, especially prominent among female subjects. Reverse MR analyses dismissed potential reverse causality between colorectal malignancies and obesity. A significant genetic interplay was observed between WHR, WHRadjBMI, and colorectal cancer instances. Ensuing MR probes spotlighted inflammatory bowel ailment as a protective factor, while salad intake was indicated as a potential risk concerning colorectal malignancies. Sensitivity reviews, which included tests for both pleiotropy and heterogeneity, validated the robustness of the MR findings.

Conclusion

Findings from this research indicate that specific obesity-related parameters, notably WHR and WHRadjBMI, carry a causal relationship with an elevated colorectal cancer risk. The impact is distinctly more evident among females. Such insights might be pivotal for public health deliberations, hinting that individuals boasting a high WHR might necessitate intensified colorectal cancer screenings.

Global burden of atrial fibrillation/flutter: Trends from 1990 to 2019 and projections until 2044

Aims

Atrial fibrillation/atrial flutter (AF/AFL) is a critical public health issue worldwide, and its epidemiological patterns have changed over the decades. This work aimed to assess the global trends of AF/AFL and attributable risks from 1990 to 2019.

Methods and results

The present study utilized data from the Global Burden of Disease Study 2019 to examine the temporal trends, attributable risks, and projections of AF/AFL. The estimated annual percentage change (EAPC) and age-standardized rate (ASR) were employed for this purpose. The findings revealed that in 2019, AF/AFL accounted for 4.72 million incident cases, 59.70 million prevalent cases, 0.32 million deaths, and 8.39 million disability-adjusted life years (DALYs). Furthermore, the results indicated that males under 70 years of age had a higher incidence, prevalence, and DALYs than females, while the rates were similar for both genders between 70 and 74 years. However, this pattern was reversed in individuals over the age of 75, with females exhibiting a higher total incidence, prevalence, and DALYs than males. The age-standardized rates (ASRs) of prevalence, incidence, mortality, and DALYs increased with an increase in the socio-demographic index (SDI). The three primary contributors to AF/AFL were high systolic blood pressure, high body-mass index, and smoking. Majority of risk factors exhibited a unimodal distribution, with a peak between the ages of 50 and 70.

Conclusions

The disease burden of AF/AFL is still severe worldwide and getting worse. To encourage prevention and treatment, systematic regional surveillance of AF/AFL should be put in place.

Obesity, obesities and gastrointestinal cancers

Obesity has been recognized to be increasing globally and is designated a disease with adverse consequences requiring early detection and appropriate care. In addition to being related to metabolic syndrome disorders such as type 2 diabetes, hypertension, stroke, and premature coronary artery disease. Obesity is also etiologically linked to several cancers. The non-gastrointestinal cancers are breast, uterus, kidneys, ovaries, thyroid, meningioma, and thyroid. Gastrointestinal (GI) cancers are adenocarcinoma of the esophagus, liver, pancreas, gallbladder, and colorectal. The brighter side of the problem is that being overweight and obese and cigarette smoking are mostly preventable causes of cancers. Epidemiology and clinical studies have revealed that obesity is heterogeneous in clinical manifestations. In clinical practice, BMI is calculated by dividing a person's weight in kilograms by the square of the person's height in square meters (kg/m2). A BMI above 30 kg/m2 (defining obesity in many guidelines) is considered obesity. However, obesity is heterogeneous. There are subdivisions for obesity, and not all obesities are equally pathogenic. Adipose tissue, in particular, visceral adipose tissue (VAT), is endocrine and abdominal obesity (a surrogate for VAT) is evaluated by waist-hip measurements or just waist measures. Visceral Obesity, through several hormonal mechanisms, induces a low-grade chronic inflammatory state, insulin resistance, components of metabolic syndrome, and cancers. Metabolically obese, normal-weight (MONW) individuals in several Asian countries may have BMI below normal levels to diagnose obesity but suffer from many obesity-related complications. Conversely, some people have high BMI but are generally healthy with no features of metabolic syndrome. Many clinicians advise weight loss by dieting and exercise to metabolically healthy obese with large body habitus than to individuals with metabolic obesity but normal BMI. The GI cancers (esophagus, pancreas, gallbladder, liver, and colorectal) are individually discussed, emphasizing the incidence, possible pathogenesis, and preventive measures. From 2005 to 2014, most cancers associated with overweight and Obesity increased in the United States, while cancers related to other factors decreased. The standard recommendation is to offer or refer adults with a body mass index (BMI) of 30 or more to intensive, multicomponent behavioral interventions. However, the clinicians have to go beyond. They should critically evaluate BMI with due consideration for ethnicity, body habitus, and other factors that influence the type of obesity and obesity-related risks. In 2001, the Surgeon General's ``Call to Action to Prevent and Decrease Overweight and Obesity'' identified obesity as a critical public health priority for the United States. At government levels reducing obesity requires policy changes that improve the food and physical activity for all. However, implementing some policies with the most significant potential benefit to public health is politically tricky. The primary care physician, as well as subspecialists, should identify overweight and Obesity based on all the variable factors in the diagnosis. The medical community should address the prevention of overweight and Obesity as an essential part of medical care as much as vaccination in preventing infectious diseases at all levels- from childhood, to adolescence, and adults.

Colorectal cancer in symptomatic patients: How to improve the diagnostic pathway

Even in countries with national screening programmes for colorectal cancer, most cancers are identified after the patient has developed symptoms. The patients present these symptoms usually to primary care, or in some countries to specialist care. In either healthcare setting, the clinician has to consider cancer to be a possibility, then to perform triage investigations, followed by definitive investigation, usually by colonoscopy. This apparently simple pathway is not simple: most symptoms of colorectal cancer are more likely to represent benign disease than cancer, and each of these stages represents selection of patients into a higher-risk pool. This article summarises a symptom-based approach to selection and initial investigation of such patients in primary care. Some special groups need particular attention, including the younger patient, those with an inherited predisposition to cancer, and those with co-morbidities.

Factors Associated with Colorectal Cancer Prevalence Among Long-Haul Truck Drivers in the United States

PURPOSE

To determine the age-adjusted association between colorectal cancer (CRC) risk factors and CRC prevalence among long-haul truck drivers (aged 21-85), after adjustment for age.

DESIGN

Pooled cross-sectional analysis using Commercial Driver Medical Exam (CDME) data. Setting. National survey data from January 1, 2005, to October 31, 2012.

PARTICIPANTS

47,786 commercial motor vehicle drivers in 48 states.

MEASURES

CRC prevalence was the primary outcome; independent variables included demographics, body mass index (BMI), and concomitant medical conditions.

ANALYSIS

Kruskal-Wallis tests to analyze continuous variables; Fischer's exact tests to analyze categorical variables; univariate and multivariable logistic regression for rare events (Firth method) to quantify the association between the independent variables of interest and CRC prevalence. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for age, gender, years with current employer, year of exam, and BMI in a multivariate logistic regression.

RESULTS

Many factors were statistically significant. Obesity (OR = 3.14; 95% CI = 1.03-9.61) and increasing age (OR = 1.10 per year; 95% CI = 1.07-1.13) were significantly associated with CRC prevalence. Truckers with 4 or more concomitant medical conditions were significantly more likely to have CRC (OR = 7.03; 95% CI = 1.83-27.03).

CONCLUSIONS

Our findings highlight mutable risk factors and represent an opportunity for intervention that may decrease CRC morbidity and mortality among truck drivers, a unique population in the United States estimated to live up to 16 years less than the general population.

Correlation of Body Mass Index with Oncologic Outcomes in Colorectal Cancer Patients: A Large Population-Based Study

It has been acknowledged that excess body weight increases the risk of colorectal cancer (CRC); however, there is little evidence on the impact of body mass index (BMI) on CRC patients' long-term oncologic results in Asian populations. We studied the influence of BMI on overall survival (OS), disease-free survival (DFS), and CRC-specific survival rates in CRC patients from the administrative claims datasets of Taiwan using the Kaplan-Meier survival curves and the log-rank test to estimate the statistical differences among BMI groups. Underweight patients (<18.50 kg/m2) presented higher mortality (56.40%) and recurrence (5.34%) rates. Besides this, they had worse OS (aHR:1.61; 95% CI: 1.53-1.70; p-value: < 0.0001) and CRC-specific survival (aHR:1.52; 95% CI: 1.43-1.62; p-value: < 0.0001) rates compared with those of normal weight patients (18.50-24.99 kg/m2). On the contrary, CRC patients belonging to the overweight (25.00-29.99 kg/m2), class I obesity (30.00-34.99 kg/m2), and class II obesity (≥35.00 kg/m2) categories had better OS, DFS, and CRC-specific survival rates in the analysis than the patients in the normal weight category. Overweight patients consistently had the lowest mortality rate after a CRC diagnosis. The associations with being underweight may reflect a reverse causation. CRC patients should maintain a long-term healthy body weight.

Video-Laparoscopic versus Open Surgery in Obese Patients with Colorectal Cancer: A Propensity Score Matching Study

Simple Summary

Extended evidence on minimally invasive surgery in colorectal cancer (CRC) settings is needed, especially as applied to obese patients. We aimed to explore and compare postoperative outcomes between open and video-laparoscopic (VL) surgery in two groups of obese patients undergoing surgical resection for CRC. VL surgery was found to reduce postoperative recovery time and the severity of complications. This Italian experience provides a further contribution to the short-term prognostic quality of minimally invasive VL surgery in obese patients.

Abstract

Background: Minimally invasive surgery in obese patients is still challenging, so exploring one more item in this research field ranks among the main goals of this research. We aimed to compare short-term postoperative outcomes of open and video-laparoscopic (VL) approaches in CRC obese patients undergoing colorectal resection. Methods: We performed a retrospective analysis of a surgical database including 138 patients diagnosed with CRC, undergoing VL (n = 87, 63%) and open (n = 51, 37%) colorectal surgery. As a first step, propensity score matching was performed to balance the comparison between the two intervention groups (VL and open) in order to avoid selection bias. The matched sample (N = 98) was used to run further regression models in order to analyze the observed VL surgery advantages in terms of postoperative outcome, focusing on hospitalization and severity of postoperative complications, according to the Clavien–Dindo classification. Results: The study sample was predominantly male (N = 86, 62.3%), and VL was more frequent than open surgery (63% versus 37%). The two subgroup results obtained before and after the propensity score matching showed comparable findings for age, gender, BMI, and tumor staging. The specimen length and postoperative time before discharge were longer in open surgery (OS) patients; the number of harvested lymph nodes was higher than in VL patients as well (p < 0.01). Linear regression models applied separately on the outcomes of interest showed that VL-treated patients had a shorter hospital stay by almost two days and about one point less Clavien–Dindo severity than OS patients on average, given the same exposure to confounding variables. Tumor staging was not found to have a significant role in influencing the short-term outcomes investigated. Conclusion: Comparing open and VL surgery, improved postoperative outcomes were observed for VL surgery in obese patients after surgical resection for CRC. Both postoperative recovery time and Clavien–Dindo severity were better with VL surgery.

Risk Factors and Genetic Predisposition in Colorectal Cancer: A Study on Young and Old Adults

According to GLOBOCAN 2018 data Colorectal cancer (CRC) represents the third most commonly diagnosed cancer in the world and has the second-highest mortality rate. The incidence of CRC has been rising worldwide, the majority of cases being in developing countries mostly due to the adoption of an unhealthy lifestyle. The main driving factors behind CRC are a sedentary lifestyle, obesity, red meat consumption, alcohol, and tobacco; however, early detection screenings and standardized treatment options have reduced CRC mortality. Better family history and genetic testing can help those with a hereditary predisposition in taking preventative measures.

Fatty Acids and Membrane Lipidomics in Oncology: A Cross-Road of Nutritional, Signaling and Metabolic Pathways

Fatty acids are closely involved in lipid synthesis and metabolism in cancer. Their amount and composition are dependent on dietary supply and tumor microenviroment. Research in this subject highlighted the crucial event of membrane formation, which is regulated by the fatty acids' molecular properties. The growing understanding of the pathways that create the fatty acid pool needed for cell replication is the result of lipidomics studies, also envisaging novel fatty acid biosynthesis and fatty acid-mediated signaling. Fatty acid-driven mechanisms and biological effects in cancer onset, growth and metastasis have been elucidated, recognizing the importance of polyunsaturated molecules and the balance between omega-6 and omega-3 families. Saturated and monounsaturated fatty acids are biomarkers in several types of cancer, and their characterization in cell membranes and exosomes is under development for diagnostic purposes. Desaturase enzymatic activity with unprecedented de novo polyunsaturated fatty acid (PUFA) synthesis is considered the recent breakthrough in this scenario. Together with the link between obesity and cancer, fatty acids open interesting perspectives for biomarker discovery and nutritional strategies to control cancer, also in combination with therapies. All these subjects are described using an integrated approach taking into account biochemical, biological and analytical aspects, delineating innovations in cancer prevention, diagnostics and treatments.

High expression of AMPD2 and obesity are associated with poor prognosis in colorectal cancer

The protein-coding gene adenosine monophosphate deaminase (AMPD) 2 plays a critical role in energy metabolism by converting adenosine-5-monophosphate (AMP) to iosine inosine-5-monophosphate (IMP). Obesity affects metabolic abnormalities in tumor cells and has been associated with high expression levels of AMPD2 and colorectal cancer (CRC). In this study, we performed immunohistochemical analysis of AMPD2 expression in 158 patients with CRC. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine AMPD2 mRNA expression levels, which were validated by The Cancer Genome Atlas (TCGA) datasets. Chi-square test and Fisher's exact test were used to evaluate the correlation between the expression of AMPD2 and clinicopathological parameters of CRC. Overall survival (OS) rates of the CRC patients were calculated using Kaplan-Meier survival analysis and a Cox proportional regression model was performed for univariate and multivariate analysis. A logistic regression model was used to plot the receiver operating characteristic (ROC) curve and to evaluate the predictive effect of multivariate studies on prognosis outcomes of CRC. We found a significant increase in AMPD2 expression in tumor tissue (91.8%, 146/158) compared to adjacent normal tissue (52.5%, 83/158, P < 0.01). The positive rate of AMPD2 expression was 72.7% (39/54) in overweight individuals versus 51.9% (54/104) in individuals with a normal weight (P = 0.014). AMPD2 mRNA levels as determined by qRT-PCR elevated levels of AMPD2 transcripts were higher in CRC samples compared to adjacent normal tissues (P < 0.05). In both the TCGA colon adenocarcinoma and rectal adenocarcinoma dataset, the number of CRC patients with increased levels of AMPD2 in tumor tissues was significantly higher compared to patients with adjacent normal tissue (P < 0.001). High expression of AMPD2 was associated with TNM stage, higher histological grade, obesity, and lower OS rates in patients with CRC. Obesity and high expression of AMPD2 in patients are with poor prognosis. Moreover, multivariate analysis indicated that AMPD2 levels and TNM stage were significant independent prognostic factors in CRC patients. The logistic regression predictive effect of the area under the curve (AUC) was 0.821 (P < 0.001). In conclusion, high levels of AMPD2 and obesity are associated with poor prognosis in patients with CRC.

Hydrolysed inulin alleviates the azoxymethane-induced preneoplastic aberrant crypt foci by altering selected intestinal microbiota in Sprague-Dawley rats

Context Inulin, a non-digestible carbohydrate isolated from Helianthus tuberosus L. (Asteraceae), has been shown to alter the gut beneficial bacteria including Lactobacillus spp. and Bifidobacteria. Inulin also influences the activities of intestinal microbiota that could prevent the colon cancer development. Objective This study determines the effect of hydrolysed inulin with different degrees of polymerisation on alteration of intestinal microbiota and their activities on azoxymethane (AOM)-induced preneoplastic aberrant crypt foci (ACF) in rats. Materials and methods Seventy-two male Sprague-Dawley rats were randomly divided into six groups (three control and three AOM-treated groups) and the animal were fed with either a normal diet or diet containing 10% of long-chain inulin (InuL) or short-chain inulin (InuS), respectively, for 17 weeks. Colon cancer was induced in rats by injecting AOM subcutaneously at the 8th and 9th week of the study period. At the end of the experiment, cecal contents of rats were examined for selected microbiota, organic acids, putrefactive compounds and microbial enzymes. ACF formation was microscopically examined. Results The inulin diets significantly increased the weight and decreased the pH of the caecal content. The rats fed with InuL-supplemented diet showed approximately 2.9- and 6.8-fold increases in the biomass of Lactobacillus spp. and Bifidobacteria, respectively. Naive and AOM-treated rats fed with inulin-supplemented diet showed ∼1.3- and ∼2.2-fold decreases in the biomass of Escherichia coli and Salmonella enterica serovar Typhi, respectively. Inulins significantly decreased the colonic concentration of phenol, p-cresol and indole. Reduction in the activity of microbial enzymes such as β-glucuronidase, azoreductase and nitroreductase were observed in inulin-treated animals. Reduction in the ACF formation has been observed in inulin-treated groups. Discussion and conclusion The present study demonstrates that dietary administration of inulin reduces the formation of preneoplastic lesions in the colon, possibly by altering the microecology and microbial activities on carcinogenesis.

Association between obesity and local control of advanced rectal cancer after combined surgery and radiotherapy

PURPOSE

The association between metabolism and cancer has been recently emphasized. This study aimed to find the prognostic significance of obesity in advanced stage rectal cancer patients treated with surgery and radiotherapy (RT).

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 111 patients who were treated with combined surgery and RT for clinical stage 2-3 (T3 or N+) rectal cancer between 2008 and 2014. The prognostic significance of obesity (body mass index [BMI] ≥25 kg/m(2)) in local control was evaluated.

RESULTS

The median follow-up was 31.2 months (range, 4.1 to 85.7 months). Twenty-five patients (22.5%) were classified as obese. Treatment failure occurred in 33 patients (29.7%), including local failures in 13 patients (11.7%), regional lymph node failures in 5, and distant metastases in 24. The 3-year local control, recurrence-free survival, and overall survival rates were 88.7%, 73.6%, and 87.7%, respectively. Obesity (n = 25) significantly reduced the local control rate (p = 0.045; 3-year local control, 76.2%), especially in women (n = 37, p = 0.021). Segregation of local control was best achieved by BMI of 25.6 kg/m(2) as a cutoff value.

CONCLUSION

Obese rectal cancer patients showed poor local control after combined surgery and RT. More effective local treatment strategies for obese patients are warranted.

Comorbidity associated with obesity in a large population: The APNA study

BACKGROUND

Overweight and obesity are major causes of comorbidities which can lead to further morbidity and mortality. The main objective of the present study was to estimate the comorbidity associated with obesity in 40,010 patients attending Primary Health Care Centres in Navarra.

METHODS

It is a descriptive cross-sectional study. The association of overweight and obesity in different diseases was studied. Odds ratios (OR) adjusted for age and sex were calculated by unconditional logistic regression, using as reference patients with body mass index (BMI) lower than 25 kg/m(2).

RESULTS

Increasing BMI is associated with glucose intolerance (OR: 1.07; 95% CI: 1.06-1.08), dyslipidemia (OR: 1.04; 95% CI: 1.03-1.04), hypertension (OR: 1.12; 95% CI: 1.12-1.13), type 2 diabetes (OR: 1.11; 95% CI: 1.10-1.11), kidney failure (OR: 1.04; 95% CI: 1.03-1.05), and osteoarthritis (OR: 1.06; 95% CI: 1.05-1.06). Moreover, all the degrees of obesity are associated with asthma (OR type I obesity: 1.33; OR type II obesity: 1.69; OR type III obesity: 1.75), heart failure (OR type I obesity: 1.68; OR type II obesity: 2.78; OR type III obesity: 4.35), and severe mental disorders (OR type I obesity: 2.02; OR type II obesity: 2.33; OR type III obesity: 2.50). Type II and morbid obesity are associated with chronic obstructive pulmonary disease and depression.

CONCLUSION

Our study showed a positive association of the overweight and obesity with glucose intolerance, dyslipidemia, type 2 diabetes, hypertension, osteoarthritis, and kidney failure. An interesting point is the association of higher levels of BMI with depression.

Diabetes and cancer: two diseases with obesity as a common risk factor

There is a growing body of evidence to support a connection between diabetes (predominantly type 2), obesity and cancer. Multiple meta-analyses of epidemiological data show that people with diabetes are at increased risk of developing many different types of cancers, along with an increased risk of cancer mortality. Several pathophysiological mechanisms for this relationship have been postulated, including insulin resistance and hyperinsulinaemia, enhanced inflammatory processes, dysregulation of sex hormone production and hyperglycaemia. In addition to these potential mechanisms, a number of common risk factors, including obesity, may be behind the association between diabetes and cancer. Indeed, obesity is associated with an increased risk of cancer and diabetes. Abdominal adiposity has been shown to play a role in creating a systemic pro-inflammatory environment, which could result in the development of both diabetes and cancer. Here, we examine the relationship between diabetes, obesity and cancer, and investigate the potential underlying causes of increased cancer risk in individuals with diabetes. Current treatment recommendations for reducing the overall disease burden are also explored and possible areas for future research are considered.

Obesity and cancer--the update 2013

Progress of the last five years regarding "Obesity and Cancer" with preference to cohort studies was reviewed for cancer of the colorectum, breast, endometrium, renal cell, and adenocarcinomas of the esophagus and compared to the knowledge reviewed in the year 2008. The new studies are mostly confirming what has been known also 5 years ago. Gender seems to play a role in colorectal cancer in that risk due to body fatness is much lower in women than in men. Body fatness at young adulthood is particularly related to risk of renal cancer whereas attained body fatness at a later stage of adulthood is driving the risk for postmenopausal breast and endometrial cancer. Fat distribution is playing a strong role for risk of adenocarcinoma of the esophagus and to a lesser extent also for colon cancer. Prediagnostic body fatness plays also a role in cancer recurrence and survival.