Adiposity and the risk of colorectal adenomatous polyps: a meta-analysis

The Association of Waist Circumference with the Prevalence and Survival of Digestive Tract Cancer in US Adults: A Population Study Based on Machine Learning Methods

Aims

This paper aims to investigate the relationship of waist circumference (WC) with digestive tract cancer morbidity and mortality.

Methods

Based on the data from a nationally representative US population survey, we summarized the prevalence of digestive tract cancer and all-cause mortality of cancer patients across WC quartiles. Adjusted logistic regression and restricted spline curve were used to analyze WC and the prevalence of digestive tract cancer. Moreover, Cox regression and the Kaplan-Meier curve were applied to investigate the association of WC with all-cause mortality. We also attempted to make a model to predict cancer happening.

Results

This paper included a total of 34,041 participants, with digestive tract cancer observed in 265 (0.7%) individuals. WC was positively associated with digestive tract cancer morbidity after full adjustment of covariates (OR: 1.72 and 95% CI: 1.41-2.10). Also, individuals in the highest WC group had a higher risk of digestive tract cancer (Q4, OR: 2.71 and 95% CI: 1.48-5.00). Moreover, no significant association was observed in upper digestive cancer, and WC was associated with a longer survival time once diagnosed (hazard ratio (HR): 0.50 and 95% CI: 0.28-0.92). Finally, the model we made proved to be effective.

Conclusion

High WC is a risk factor for digestive tract cancer with or without adjusting for body mass index, especially those located in the lower digestive tract. However, once digestive tract cancer has been diagnosed, patients with higher WC showed better survival outcomes. Moreover, machine learning methods can be used to predict digestive tract cancer risk in the future.

Obesity, Cancer, and Risk Reduction with Bariatric Surgery

The prevalence of noncommunicable diseases has increased dramatically in North America and throughout the world and is expected to continue increasing in coming years. Obesity has been linked to several types of cancers and is associated with increased morbidity and mortality following cancer diagnosis. Bariatric surgery has emerged as the prominent model to evaluate the effects of intentional weight loss on cancer incidence and outcomes. Current literature, comprising prospective cohort investigations, indicates site-specific reductions in cancer risk with select bariatric procedures. Future research is required to establish evidence-based indications for bariatric surgery in the context of cancer prevention.

Emerging trends in colorectal cancer: Dysregulated signaling pathways (Review)

Colorectal cancer (CRC) is the third most frequently detected type of cancer, and the second most common cause of cancer‑related mortality globally. The American Cancer Society predicted that approximately 147,950 individuals would be diagnosed with CRC, out of which 53,200 individuals would succumb to the disease in the USA alone in 2020. CRC‑related mortality ranks third among both males and females in the USA. CRC arises from 3 major pathways: i) The adenoma‑carcinoma sequence; ii) serrated pathway; and iii) the inflammatory pathway. The majority of cases of CRC are sporadic and result from risk factors, such as a sedentary lifestyle, obesity, processed diets, alcohol consumption and smoking. CRC is also a common preventable cancer. With widespread CRC screening, the incidence and mortality from CRC have decreased in developed countries. However, over the past few decades, CRC cases and mortality have been on the rise in young adults (age, <50 years). In addition, CRC cases are increasing in developing countries with a low gross domestic product (GDP) due to lifestyle changes. CRC is an etiologically heterogeneous disease classified by tumor location and alterations in global gene expression. Accumulating genetic and epigenetic perturbations and aberrations over time in tumor suppressor genes, oncogenes and DNA mismatch repair genes could be a precursor to the onset of colorectal cancer. CRC can be divided as sporadic, familial, and inherited depending on the origin of the mutation. Germline mutations in APC and MLH1 have been proven to play an etiological role, resulting in the predisposition of individuals to CRC. Genetic alterations cause the dysregulation of signaling pathways leading to drug resistance, the inhibition of apoptosis and the induction of proliferation, invasion and migration, resulting in CRC development and metastasis. Timely detection and effective precision therapies based on the present knowledge of CRC is essential for successful treatment and patient survival. The present review presents the CRC incidence, risk factors, dysregulated signaling pathways and targeted therapies.

Lifestyle factors and risk for colorectal polyps and cancer at index colonoscopy in a FIT-positive screening population

Background

Many countries have adopted the fecal immunochemical test (FIT) as the primary colorectal cancer (CRC) screening tool; however, its accuracy is limited. Epidemiological studies have shown that obesity and type 2 diabetes increase risk for the disease.

Objective

The objective of this article is to evaluate the association of colorectal polyps and cancer with comorbidities and lifestyle factors in a population that is part of a FIT-based CRC screening program.

Methods

Between 2005 and 2013, we analyzed 3894 FIT + patients who underwent total colonoscopy. The impact of lifestyle factors on polyps and cancer was assessed using individuals with a negative colonoscopy as the control group. A multivariate logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

We collected data from 3894 FIT + patients. Obesity (OR 1.29; 95% CI 1.05-1.60) and smoking (OR 1.45; 95% CI 1.24-1.71) were significantly associated with high-risk adenomas. Smoking and heavy alcohol drinking were both independently associated with high risk of CRC (OR 1.50; 95% CI 1.10-2.04 and OR 2.29; 95% CI 1.15-4.58) and colon cancer alone (OR 1.43; 95% CI 1.01-2.02 and OR 3.09; 95% CI 1.53-6.23). Positivity to first round of FIT was associated with high-risk adenomas (OR 1.47; CI 95% 1.26-1.71) and CRC (OR 1.74; 95% CI 1.29-2.36). No associations were found for diabetes.

Conclusion

In our FIT + population, lifestyle factors are significantly associated with the risk of carrying high-risk adenomas and CRC. In the future, studies could be aimed at finding better screening strategies through the development of clinical algorithms based on lifestyle changes/comorbidities.

Adult weight gain and colorectal adenomas-a systematic review and meta-analysis

Background

Colorectal adenomas are known as precursors for the majority of colorectal carcinomas. While weight gain during adulthood has been identified as a risk factor for colorectal cancer, the association is less clear for colorectal adenomas. We conducted a systematic review and meta-analysis to quantify the evidence on this association.

Methods

We searched Medline up to September 2016 to identify observational (prospective, cross-sectional and retrospective) studies on weight gain during adulthood and colorectal adenoma occurrence and recurrence. We conducted meta-analysis on high weight gain versus stable weight, linear and non-linear dose-response meta-analyses to analyze the association. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using a random effects model.

Results

For colorectal adenoma occurrence, the summary OR was 1.39 (95% CI: 1.17-1.65; I2: 43%, N = 9 studies, cases = 5507) comparing high (midpoint: 17.4 kg) versus stable weight gain during adulthood and with each 5 kg weight gain the odds increased by 7% (2%-11%; I2: 65%, N = 7 studies). Although there was indication of non-linearity (Pnon-linearity < 0.001) there was an increased odds of colorectal adenoma throughout the whole range of weight gain. Three studies were identified investigating the association between weight gain and colorectal adenoma recurrence and data were limited to draw firm conclusions.

Conclusions

Even a small amount of adult weight gain was related to a higher odds of colorectal adenoma occurrence. Our findings add to the benefits of weight control in adulthood regarding colorectal adenoma occurrence, which might be relevant for early prevention of colorectal cancer.

Myeloperoxidase-positive cell infiltration of normal colorectal mucosa is related to body fatness and is predictive of adenoma occurrence

Body fatness is a risk factor for colorectal cancer, and promotes an inflammatory environment. Indeed, inflammation in normal colorectal mucosa may be a factor linking body fatness to colorectal carcinogenesis. In this study, we evaluated myeloperoxidase (MPO)-positive cells infiltration of normal colorectal mucosa as a marker of cancer-promoting inflammation in overweight and obese subjects. One hundred and three subjects with normal colonoscopy entered the study. Waist circumference (WC) and body mass index (BMI) were measured, and MPO-positive cells on histological sections of biopsies of normal colorectal mucosa were counted under a light microscope. The occurrence of adenomas was then evaluated on follow-up colonoscopies. Mean MPO-positive cell count (±s.e.m.) was higher in subject with a WC equal or above the obesity cutoff values according to gender (2.63±0.20 vs 2.06±0.18, P=0.03), and in subjects with BMI equal or above 25 kg m^-2 (2.54±0.18 vs 1.97±0.20, P=0.03). A Cox proportional hazard model showed that mean MPO-positive cell count in normal colorectal mucosa was the only factor independently related to occurrence of adenomas in follow-up colonoscopies. Though preliminary, these results show that MPO-positive cell infiltration in normal colorectal mucosa is related with body fatness, as evaluated by WC and BMI, and it may be considered a useful and simple marker to estimate adenoma occurrence risk.

Increased Risk of Advanced Colorectal Neoplasia Among Korean Men With Metabolic Abnormality and Obesity

BACKGROUND & AIMS

Obesity and metabolic abnormality are risk factors for colorectal cancer and adenoma. We evaluated the risk of advanced colorectal neoplasm (AN) according to metabolic status and obesity in Koreans.

METHODS

We performed a retrospective cross-sectional study of 70,428 individuals in Korea who underwent colonoscopy and whose metabolic state and body mass index were examined, from 2003 through 2012, at Kangbuk Samsung Hospital in Korea. We calculated odds ratios (ORs) for AN in people who were metabolically healthy but obese, people with metabolic abnormality who were not obese, and people with metabolic abnormality who were obese. The reference group was metabolically healthy nonobese peoples. AN was defined as adenoma ≥10 mm in diameter, adenoma with any component of villous histology, high-grade dysplasia, or invasive cancer.

RESULTS

No increased risk of AN was observed in the metabolically healthy but obese (OR, 0.99; 95% confidence interval [CI], 0.67-1.46; P = .825) and metabolic abnormality who were not obese groups (OR, 1.01; 95% CI, 0.85-1.21; P = .765). In contrast, risk of AN was increased in the metabolic abnormality who were obese group (OR, 1.33; 95% CI, 1.12-1.58; P = .006). In men, risk of AN showed a greater increase in the metabolic abnormality who were obese group (OR, 1.48; 95% CI, 1.20-1.83; P = .001). This association was not observed in women (OR, 1.21; 95% CI, 0.84-1.75; P = .476).

CONCLUSIONS

Men with 1 or more metabolic abnormality and obesity are at increased risk for AN.

Obesity and Colorectal Cancer

There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.

Awareness of Lifestyle and Colorectal Cancer Risk: Findings from the BeWEL Study

It is estimated that 47% of colorectal cancers (CRC) could be prevented by appropriate lifestyles. This study aimed to identify awareness of the causes of CRC in patients who had been diagnosed with a colorectal adenoma through the Scottish Bowel Screening Programme and subsequently enrolled in an intervention trial (using diet and physical activity education and behavioural change techniques) (BeWEL). At baseline and 12-month follow-up, participants answered an open-ended question on factors influencing CRC development. Of the 329 participants at baseline, 40 (12%) reported that they did not know any risk factors and 36 (11%) failed to identify specific factors related to diet and activity. From a potential knowledge score of 1 to 6, the mean score was 1.5 (SD 1.1, range 0 to 5) with no difference between intervention and control groups. At follow-up, the intervention group had a significantly greater knowledge score and better weight loss, diet, and physical activity measures than the control group. Awareness of relevant lifestyle factors for CRC remains low in people at increased risk of the disease. Opportunities within routine NHS screening to aid the capability (including knowledge of risk factors) of individuals to make behavioural changes to reduce CRC risk deserve exploration.

Relationship between body mass index and the risk of early gastric cancer and dysplasia regardless of Helicobacter pylori infection

BACKGROUND

Obesity is known to be associated with an increased risk of gastric cardia cancer but not with noncardia cancer. In terms of gastric dysplasia, few studies have evaluated its relationship with obesity. In addition, no study on the relationship between obesity and the risk of gastric cancer has analyzed the status of Helicobacter pylori infection.

METHODS

A case-control study was designed to investigate the relationship between obesity and the risk of gastric cancer and dysplasia adjusted for the status of H. pylori infection in Koreans. Nine hundred ninety-eight gastric cancer patients, 313 gastric dysplasia patients, and 1,288 subjects with normal endoscopic findings were included.

RESULTS

As gender differences could be the largest confounding factor, the risk of gastric cancer and dysplasia with an increasing body mass index (BMI) was analyzed in men and women, separately, and was adjusted for age, smoking, drinking, family history of gastric cancer, H. pylori infection, atrophic gastritis, intestinal metaplasia, and serum pepsinogen I/pepsinogen II ratio. Obesity (BMI 25 kg/m(2) or greater but less than 30 kg/m(2)) was associated with increased risk of early gastric cancer [adjusted odds ratio (aOR) 1.657; 95 % confidence interval (CI) 1.086-2.528; P = 0.019] and well or moderately differentiated adenocarcinoma (aOR 1.566; 95 % CI 1.011-2.424; P = 0.044) compared with normal BMI status (BMI < 23 kg/m(2)) in men. Obesity was related to gastric dysplasia (aOR 2.086; 95 % CI 1.011-4.302; P = 0.047) in women.

CONCLUSIONS

The effect of obesity on gastric cancer showed a gender difference. That is, in men it was related to increased risk of early gastric cancer and well or moderately differentiated adenocarcinoma, but it was associated with gastric dysplasia in women regardless of H. pylori infection in Korea. Further research into this difference is necessary.

Hyperinsulinemia, insulin resistance and colorectal adenomas: A meta-analysis

BACKGROUND

Insulin stimulates cell proliferation and inhibits apoptosis. While epidemiologic studies have investigated associations between markers of insulin resistance/hyperinsulinemia (i.e., circulating insulin, homeostasis model assessment-insulin resistance (HOMA-IR), C-peptide) and risk of colorectal adenoma (CRA), the effect size has not yet been quantified.

OBJECTIVE

We aimed to summarize the association between hyperinsulinemia/insulin resistance and risk of CRA, including whether the association is independent of adiposity.

MATERIALS AND METHODS

Pubmed and Embase were searched through April, 2015 to identify observational studies investigating the associations between insulin, C-peptide and HOMA-IR and CRA risk. Using the highest versus lowest category meta-analysis and dose-response meta-analysis based on a random-effects model, we estimated summary odds ratio (OR) and the corresponding 95% confidence interval (95% CI).

RESULTS

A total of 27 studies (insulin: 16 studies including 14,007 cases; C-peptide: 11 studies including 8639 cases; HOMA-IR: 8 studies including 11,619 cases) were included in this meta-analysis. The summary ORs of CRA comparing the highest with the lowest quantile were 1.33 for insulin (95% CI=1.12-1.58, I(2)=73.9%, Pheterogeneity<0.001), 1.44 for C-peptide (95% CI=1.13-1.83, I(2)=63.5%, Pheterogeneity=0.003), and 1.33 for HOMA-IR (95% CI=1.10-1.60, I(2)=69.1%, Pheterogeneity=0.004). Upon stratification by ethnicity, higher levels of insulin and C-peptide were significantly associated with increased risk of CRA in non-Asian ethnicity (summary OR for insulin=1.67 [95% CI=1.28-2.17], I(2)=34.9%, Pheterogeneity=0.16; summary OR for C-peptide=1.59 [95% CI=1.22-2.08], I(2)=21.5%, Pheterogeneity=0.27) but not in Asians (summary OR for insulin=1.10 [95% CI=0.92-1.33], I(2)=76.6%, Pheterogeneity=0.001; summary OR for C-peptide=1.27 [95% CI=0.84-1.91], I(2)=72.6, Pheterogeneity=0.01). We observed evidence for the existence of publication bias for insulin (P=0.01 by Egger test) and HOMA-IR (P=0.05 by Egger test). The results were confirmed in linear dose-response meta-analysis. These significant positive associations generally persisted even after adjustment for adiposity, although the effect size was substantially attenuated.

CONCLUSIONS

Independent of adiposity, higher levels of insulin, C-peptide, and HOMA-IR were significantly associated with increased risk of CRA. The weaker associations and high heterogeneity in Asian studies warrant further research. These results indicate that insulin resistance and hyperinsulinemia may contribute in part to the association between obesity and CRA risk.

Colorectal adenomas and diabetes: implications for disease prevention

AIM

This study assessed the baseline type II diabetes mellitus (T2DM) risk status among overweight patients with screen-detected colorectal adenomas and explored the implications of the findings for preventative practice.

METHOD

Participants aged between 50 and 74 years (73% of whom were men) were recruited from four Scottish health boards and assessed for diabetes risk. Participants were categorized as at 'high' diabetes risk if glycated haemoglobin (HbA1c) was between 6.0 and 6.4% or fasting plasma glucose (FPG) was between 5.5 and 6.9 mmol/l and as potentially undiagnosed T2DM when HbA1c ≥ 6.5% or FPG ≥ 7 mmol/l. Secondary outcome measures included anthropometric measurements, blood pressure and the plasma lipid profile. The tests were repeated at 12 months and diabetes risk categories were reassessed following intervention procedures.

RESULTS

Forty-seven (14.3%) of the 329 participants had a preexisting diagnosis of T2DM. Of the remainder with complete biochemistry results (n = 250), 19 (7.6%) were classified as having potentially undiagnosed T2DM and 125 (50.0%) as being at high risk of developing diabetes. More than a quarter of participants in all categories had raised waist circumference, hypertension and plasma lipids, indicative of raised cardiovascular risk. At 12 months' follow-up, the diabetes risk category diminished in 20% of the intervention group vs 11% in the controls [OR 2.26 (95% CI 1.03-4.96)].

CONCLUSION

Our results suggest that a diagnosis of adenoma in overweight patients provides a health service opportunity for diabetes assessment, prevention and management in a high-risk population at a potentially teachable moment.

Republished: obesity and colorectal cancer

Excess body weight, as defined by the body mass index (BMI), has been associated with several diseases and includes subjects who are overweight (BMI≥25-29.9 kg/m(2)) or obese (BMI≥30 kg/m(2)). Overweight and obesity constitute the fifth leading risk for overall mortality, accounting for at least 2.8 million adult deaths each year. In addition around 11% of colorectal cancer (CRC) cases have been attributed to overweight and obesity in Europe. Epidemiological data suggest that obesity is associated with a 30-70% increased risk of colon cancer in men, whereas the association is less consistent in women. Similar trends exist for colorectal adenoma, although the risk appears lower. Visceral fat, or abdominal obesity, seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m(2) increase in BMI confers additional risk (HR 1.03). Obesity might be associated with worse cancer outcomes, such as recurrence of the primary cancer or mortality. Several factors, including reduced sensitivity to antiangiogenic-therapeutic regimens, might explain these differences. Except for wound infection, obesity has no significant impact on surgical procedures. The underlying mechanisms linking obesity to CRC are still a matter of debate, but metabolic syndrome, insulin resistance and modifications in levels of adipocytokines seem to be of great importance. Other biological factors such as the gut microbita or bile acids are emerging. Many questions still remain unanswered: should preventive strategies specifically target obese patients? Is the risk of cancer great enough to propose prophylactic bariatric surgery in certain patients with obesity?

Colorectal polyp model established by transplacental BMP4 RNAi

Previous studies have shown that disruption of the bone morphogenetic protein (BMP) signaling pathway is an important cause of intestinal cancer in human and animal models. Thus, the purpose of this study was to construct a Balb/C model of colorectal polyps. Pregnant mice at 9.5 days gestation were injected via the tail vein with the pSES-Si BMP4 plasmid bearing a fluorochrome (DsRed) reporter, in order to silence the BMP4 gene in the first generation (F1); this group of mice was named the pSES-BMP4 group Intestinal fluorescence was detected at 1-, 4- and 8-week-old F1 mice, and reverse transcription-polymerase chain reaction (RT-PCR) and western-blotting assays were used to determine changes in the expression of BMP4. A dissecting microscope and hematoxylin and eosin (H&E) staining were used to observe the cell morphology and appearance of the polyps. DsRed fluorescence was observed in the intestines of 1-week-old F1 mice of the pSES-BMP4 group. BMP4 expression at the mRNA and protein level was reduced in 1-, 4- and 8-week-old F1 mice (P<0.05). However, the level of Smad4 mRNA was only reduced in 8-week-old F1 mice (P<0.05). Multiple hyperplasic polyps emerged in the colon and rectum of the intestines of 4-week-old F1 mice in the pSES-BMP4 group. The size of colorectal polyps increased at 8 weeks, when vessels and polyp pedicles became apparent. In conclusion, silencing of the BMP4 gene using transplacental RNAi injection can induce formation of colorectal polyps in mice.

Associations between diet-related diseases and impaired physiological mechanisms: a holistic approach based on meta-analyses to identify targets for preventive nutrition

In nutrition research, analyzing the relationship between a diet-related chronic disease and impaired metabolism is a common reductionist approach. Meta-analyses have enabled quantification of these relationships. There is, however, a need for more holistic approaches to determine the sequence of connections between diseases and associated physiological mechanisms. The objective of this exhaustive review was to collect scientific evidence – with priority given to quantitative reviews – published between 1950 and 2011 to assess the relationships between major diet-related chronic diseases and deregulated mechanisms. The results revealed that diabetes and obesity are the key diseases that lead to all other diet-related chronic diseases, while cancer, cardiovascular disease, skeletal disease, and sarcopenia are endpoint diseases. Liver disease, kidney disease, digestive disease, and mental illness are consequences as well as causes of other diet-related chronic diseases. All diseases have multifactorial causes, and most result from decreased antioxidant status, acid-base imbalance, increased inflammatory status, impaired carbohydrate/lipid/one-carbon metabolism, impaired functioning of neurons and DNA transcription, hypertension, and/or modified digestive microflora. Nutritional strategies that focus on the prevention of obesity and diabetes should be prioritized in order to reduce the prevalence of other major chronic diseases.

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.