Obesity, weight gain and risk of colon adenomas in Japanese men

Association of 25(OH)-Vitamin D and metabolic factors with colorectal polyps

BACKGROUND

Studies have revealed the association of vitamin D with specific types of cancer development, however, its correlation with colorectal polyps (CRPs) remains unverified. Our study aimed to investigate the relationship between vitamin D levels, metabolic factors, and CRPs.

METHODS

A cross-sectional study from 2017 to 2019 involving 1306 participants was conducted to investigate the association among vitamin D levels, metabolic factors, uric acid and CRPs in Taiwan. CRPs diagnoses were determined via colonoscopies conducted by experienced gastrointestinal physicians, and biopsied polyps were inspected under a microscope by experienced pathologists. We employed both simple and multiple logistic regression analyses to identify significant factors associated with CRPs and adenomatous polyps, respectively.

RESULTS

Our result showed that the prevalence of 25(OH)-vitamin D deficiency (≦ 20 ng/mL) and CRPs was 21.21% and 40.89%, respectively. Multiple logistic regression revealed that the risk of CRPs increased with old age, male sex, hyperglycemia, high triglyceride levels, and low 25(OH)D levels after adjustment for other factors. Besides, low 25(OH)D levels were significantly associated with CRPs risk in women, whereas elevated blood pressure was associated with CRPs risk in men. 25(OH)D Deficiency was revealed to be significantly associated with risk of CRPs in adults over 50 years old. Compared to nonadenomatous polyps, older age, higher 25(OH) vitamin D and higher uric acid levels were at increased risk for adenomatous polyps.

CONCLUSIONS

Our study revealed that vitamin D deficiency was significantly associated with the risk of CRPs, especially in adults over 50 years old and women. We should therefore be concerned about the CRP risk of vitamin D deficiency and metabolic syndrome (especially hyperglycemia, elevated blood pressure in men, and high triglyceride levels) in this population.

The impact of body weight on dysplasia of colonic adenomas: a case-control study

OBJECTIVE

Colorectal cancer (CRC) is common across countries in males and females. Most cases originate from adenomas harboring high grade dysplasia. Among risk factors, weight excess has been suggested to positively influence dysplasia progression. In this study, the relationship between dysplasia grade of adenomas and body mass index (BMI) categories was analyzed.

METHODS

This was a retrospective case-control study. A total of 4745 charts (59.8% females) from patients undergoing colonoscopy were collected. Data regarding age, sex, smoking habits, occupation, residence, personal history of CRC, personal history of polyps and BMI were retrieved. Adenomas with high-grade dysplasia were labeled as advanced.

RESULTS

They were 970 (20.4%) subjects with adenomas (cases: mean age 64.67 ± 11.35 years) and 3775 without (controls: mean age 56.43 ± 16.56 years). As expected, adenomas were significantly associated with overweight or obesity. After adjusting for all covariates the presence of advanced adenoma was significantly associated with age, male sex, smoking habits, personal history of CRC, overweight (OR = 1.298, IC 95% 1.092-1.697) and obesity (OR = 1.780, IC 95% 1.260-2.515).

CONCLUSIONS

Our findings support the protective effect a normal weight against advanced adenomas. Reduction of BMI value should be pursued in healthy programs.

Physically active individuals have a 23% lower risk of any colorectal neoplasia and a 27% lower risk of advanced colorectal neoplasia than their non-active counterparts: systematic review and meta-analysis of observational studies

BACKGROUND

Few studies have examined the associations between physical activity (PA), sedentary behaviour (SB) and risk of colorectal neoplasia (CN).

METHODS

We systematically searched Medline, Embase, PsyInfo, Cochrane and other sources from their inception to 30 September 2018 for cohort, case-control and cross-sectional studies that evaluated these associations in asymptomatic, average-risk subjects. Random-effect models were used to estimate relative risks (RRs) of any-type CN, advanced CN, and non-advanced CN, respectively, in individuals with the highest versus the lowest level of PA and SB. Dose-response analyses and subgroup analyses were conducted. The I² statistic was used to examine heterogeneity among studies.

RESULTS

We identified 32 observational studies, including 17 cross-sectional studies, 10 case-control studies and five longitudinal studies. PA (highest vs lowest) was inversely associated with risk for any-type CN (n=23 studies) and advanced CN (n=15 studies), with a RR of 0.77 (95% CI=0.71 to 0.83, I²=57.5%) and 0.73 (95% CI=0.63 to 0.82, I²=45.5%), respectively. There was no association between PA and non-advanced CN (n=5 studies). There was an as association between PA and any-type CN in both sexes, and also for the distal colon. We found no dose-response relationship between PA and any-type or advanced CN. Based on three studies identified, SB time (longest vs shortest) was associated with an increased risk of advanced CN (RR=1.24, 95% CI 1.04 to 1.49, I²=14.4%). No publication bias was detected by Begg's test.

CONCLUSION

We report a 23% lower relative risk of any type of CN and a 27% lower risk of advanced CN in people with the highest level of PA compared with those in the lowest.

Anti-cancer effect of Indanone-based thiazolyl hydrazone derivative on colon cancer cell lines

Colorectal cancer is the third leading cause of cancer related deaths in the United States. Currently, Irinotecan, a topoisomerase I inhibitor, is an approved anti-cancer drug for the treatment of patients with advanced or recurrent colorectal cancer. Considering low response rate and events of high toxicity caused by irinotecan, we evaluated a series of thirteen thiazolyl hydrazone derivatives of 1-indanone for their potential antineoplastic activity and four compounds showed promising anti-cancer activity against most of the tested colon cancer cell lines with IC₅₀ values ranging from 0.41 ± 0.19 to 6.85 ± 1.44 μM. It is noteworthy that the compound, N-Indan-1-ylidene-N'-(4-Biphenyl-4-yl-thiazol-2-yl)-hydrazine (ITH-6) is found to be more effective than irinotecan against colon cancer cells, HT-29, COLO 205, and KM 12. Mechanistic studies reveal that ITH-6 arrests these cancer cell lines in G2/M phase of the cell cycle, induces apoptosis and causes an increase in ROS level with a significant reduction in the GSH level. The mechanism of inhibition relates to the inhibition of tubulin polymerization in the mitotic phase. These findings suggest that ITH-6 is a novel drug candidate for the treatment of colorectal cancer.

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.

Changes in Adult BMI and Waist Circumference Are Associated with Increased Risk of Advanced Colorectal Neoplasia

BACKGROUND

Waist circumference (WC) is a stronger predictor of colon cancer (CRC) risk than body mass index (BMI). However, how well change in either WC or BMI predicts risk of advanced colorectal neoplasia (AN) is unclear.

AIMS

To determine the relationship between change in BMI and WC from early adulthood to later age and the risk of AN and which change measure is a stronger predictor.

METHODS

In 4500 adults, ages 50-80, with no previous neoplasia and undergoing screening colonoscopy, BMI and WC at age 21 and at time of screening were reported. Changes in BMI and WC were defined using universal risk cutoffs. Known CRC risk factors were controlled in the logistic models.

RESULTS

Overall, model statistics showed WC change (omnibus test χ ² = 10.15, 2 DF, p value = 0.006) was a statistically stronger predictor of AN than BMI change (omnibus test χ ² = 5.66, 5 DF, p value = 0.34). Independent of BMI change, participants who increased WC (OR 1.44; 95% CI 1.05-1.96) or maintained a high-risk WC (OR 2.50; 95% CI 1.38-4.53) at age 21 and at screening had an increased risk of AN compared to those with a low-risk WC. Study participants who were obese at age 21 and at screening had an increased risk of AN (OR 1.87; 95% CI 1.08-3.23) compared to those who maintained a healthy BMI. Maintaining an overweight BMI or increasing BMI was not associated with AN.

CONCLUSIONS

Maintaining an unhealthy BMI and WC throughout adult life may increase risk of AN. WC change may be a better predictor of AN than BMI change.

Elevated Neutrophil-to-Lymphocyte Ratio in Metabolic Syndrome Is Associated with Increased Risk of Colorectal Adenoma

BACKGROUND

Metabolic syndrome (MetS) is an important cardiovascular risk factor for insulin resistance and has been linked to colorectal adenoma via inflammation. The neutrophil-to-lymphocyte ratio (NLR) has been suggested as an important inflammatory marker. We initiated this investigation to determine the relationship between colorectal adenoma and NLR in patients with MetS.

METHODS

We examined participants who visited the Health Promotion Center at Kosin University Gospel Hospital, Busan, Korea. Subjects who underwent both colonoscopy and liver ultrasonography were included. Colorectal adenoma was defined as the presence of a colon polyp with a histologically adenomatous component. MetS was defined according to the modified National Cholesterol Education Program Adult Treatment Panel III definition for South Asians. Anthropometric measurements and biochemical tests of liver and metabolic function were assessed.

RESULTS

A total of 1007 subjects were included in the study sample. Their mean age was 48.3 ± 9.7 years and 262 (26.0%) subjects had MetS, while 439 (43.6%) subjects had pathologically proven colorectal adenoma. Subjects with MetS were older, more likely to be male, and had significantly higher prevalences of colorectal adenoma (49.2% vs. 41.6%, P = 0.032), nonalcoholic fatty liver disease (62.8% vs. 19.5%, P < 0.001), and higher NLR (2.0 ± 0.9 vs. 1.7 ± 0.7, P < 0.001) compared to those without MetS. High NLR (≥2.0) was an independent factor affecting the prevalence of colorectal adenoma [odds ratio (OR) 1.38, confidence interval (95% CI) 1.02-1.88, P = 0.040], especially in subjects with MetS (OR 1.91, 95% CI 1.12-3.28, P = 0.018).

CONCLUSION

High NLR was associated with increased colorectal adenomatous polyps, particularly in subjects with MetS. Screening colonoscopies for the prevention of colorectal adenoma may be warranted for patients with high NLR and MetS.

Association between Nutrient Intake and Metabolic Syndrome in Patients with Colorectal Cancer

The purpose of this study was to investigate the difference of nutritional status according to metabolic syndrome in colorectal cancer patients. The subjects were divided into 2 groups (metabolic syndrome group and normal group) according to the presence or absence of metabolic syndrome in 143 patients diagnosed with colorectal cancer, and their lifestyle and nutritional status were analyzed. Recall method was used for the dietary survey, and metabolic syndrome was defined as the presence of 3 or more of waist circumference, fasting blood glucose, triglyceride, high-density lipoprotein (HDL)-cholesterol, and blood pressure. This study showed that the metabolic syndrome group had a low age, a high body mass index (BMI), and a high drinking rate. The intake of energy, protein, fat, calcium, and phosphorus was significantly higher in the metabolic syndrome group than in the normal group, and the intake of β-carotene, vitamin C, and folic acid was significantly low. The intake of cholesterol, fatty acid, saturated fatty acid, and polyunsaturated fatty acid was also higher in the metabolic syndrome group. Higher BMI, alcohol consumption, intake of fat, total fatty acid or saturated fatty acid increased the risk of metabolic syndrome, but fiber, vitamin C, or folic acid intake lowered the risk.Weight management and balanced nutritional intake should be emphasized to prevent metabolic syndrome and to improve the condition in patients with colorectal cancer.

Association Between Colorectal Cancer and Atherosclerotic Diseases: A Study Using a National Inpatient Database in Japan

BACKGROUND

Both colorectal neoplasms and atherosclerosis can be induced by common visceral fat accumulation. However, the association between these diseases at the advanced stage, colorectal cancer and cardiovascular/cerebrovascular diseases, has not been elucidated.

AIMS

This study aimed to investigate the association between colorectal cancer and vascular diseases in relation to obesity and metabolic disorders, using a nationwide database of hospitalized patients in Japan. We used non-cardiac gastric cancer patients as a reference, because they were considered to be neutral for obesity or metabolic disorders.

METHODS

We identified 54,591 patients with colorectal cancer and 19,565 patients with gastric cancer from the Diagnosis Procedure Combination database. The data collected included: sex; age; body mass index (BMI); smoking status; comorbidity; and medication data, comprising hypertension, diabetes, hyperlipidemia, coronary artery disease, and stroke. We compared these data in a cross-sectional setting by multivariate analyses.

RESULTS

Multivariate logistic regression analyses showed that female sex, increased BMI, hypertension [odds ratio (OR) 1.11; 95 % confidence interval (CI) 1.07-1.15; P < 0.0001], and diabetes (OR 1.17; 95 % CI 1.12-1.23; P < 0.0001) were more associated with colorectal cancer than with gastric cancer. Smoking, aspirin use (OR 0.85; 95 % CI 0.79-0.92; P < 0.0001), and coronary artery disease (OR 0.90; 95 % CI 0.86-0.95; P = 0.0001) were inversely associated with colorectal cancer.

CONCLUSIONS

Obesity and metabolic disorders were more associated with colorectal cancer than with non-cardiac gastric cancer, while coronary artery disease (CAD) was inversely associated. Some mechanisms involving separate populations of colorectal cancer and CAD under visceral fat accumulation might be suggested.

Bardoxolone Methyl Prevents High-Fat Diet-Induced Colon Inflammation in Mice

Obesity induces chronic, low-grade inflammation, which increases the risk of colon cancer. We investigated the preventive effects of Bardoxolone methyl (BARD) on high-fat diet (HFD)-induced inflammation in a mouse colon. Male C57BL/6J mice (n=7) were fed a HFD (HFD group), HFD plus BARD (10 mg/kg) in drinking water (HFD/BARD group), or normal laboratory chow diet (LFD group) for 21 weeks. In HFD mice, BARD reduced colon thickness and decreased colon weight per length. This was associated with an increase in colon crypt depth and the number of goblet cells per crypt. BARD reduced the expression of F4/80 and CD11c but increased CD206 and IL-10, indicating an anti-inflammatory effect. BARD prevented an increase of the intracellular pro-inflammatory biomarkers (NF-қB, p NF-қB, IL-6, TNF-α) and cell proliferation markers (Cox2 and Ki67). BARD prevented fat deposition in the colon wall and prevented microbial population changes. Overall, we report the preventive effects of BARD on colon inflammation in HFD-fed mice through its regulation of macrophages, NF-қB, cytokines, Cox2 and Ki67, fat deposition and microflora.

Prevalence of colorectal adenomatous polyps in patients with chronic obstructive pulmonary disease

Background

Colorectal adenomatous polyps are precancerous lesions of colorectal cancer. The aim of this study was to assess the prevalence of colorectal adenomatous polyps in chronic obstructive pulmonary disease (COPD) patients and determine whether COPD is associated with colorectal malignant potential.

Methods

Subjects who had undergone post-bronchodilator spirometry and colonoscopy and were 40 years or older were selected from the hospital database. COPD was defined as a spirometry in which the ratio of forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) is <0.7 in post-bronchodilator spirometry. The non-COPD group was matched for both age and sex, and were defined as having an FEV₁, FVC, and FEV₁/FVC ≥0.7 in spirometry. Finally, 333 patients were retrospectively reviewed; of this group, 82 patients had COPD.

Results

Among the subjects, 201 patients (60%) were nonsmokers, while 78 (23%) were current smokers. The prevalence of colorectal adenomatous polyps was 39% (98/251) in the non-COPD group and 66% (54/82) in the COPD group. Among 54 patients with adenomatous polyps in the COPD group, 47 had tubular adenoma and seven had villous adenoma. Multiple logistic regression analyses revealed that only COPD patients whom matched to the criteria of COPD by pulmonary function test (odds ratio 2.1, 95% confidence interval: 1.1–3.8; P=0.019) were independently associated with colorectal malignant potential.

Conclusion

The risk of colorectal malignant potential in the COPD group was higher than in the non-COPD group. We may suggest that COPD patients should consider regular colonoscopic evaluation to screen for premalignant colon polyps regardless of smoking.

Effect of metabolic syndrome and its components on survival in colorectal cancer: a prospective study

Introduction: Metabolic syndrome (MetS) may affect prognosis of the patients diagnosed with colorectal cancer (CRC).

Objectives: This study was aimed to design a model and to examine the prognostic effect of MetS on survival time in the patients with CRC.

Patients and Methods: Data were collected from 1127 cases of CRC from Cancer Registry Center of the Research Institute of Gastroenterology and Liver Disease, Shahid Beheshti University of Medical Sciences, Tehran, Iran. In this cohort study, patients were divided into two groups based on the presence of MetS. We tested the prognostic value of MetS in the patients by Cox proportional hazard modeling.

Results: Mean ± standard deviation of the patients’ age at diagnosis in MetS group and non-MetS group was 56 ± 13 years old and 53 ± 15 years old respectively. Tumor stage as an independent variable affected CRC survival. The mean survival time of the MetS and non-MetS groups was 23 and 27 months respectively. Independent variables like tumor stage (hazard ratio [HR], 1.76; 95% CI, 0.29–0.90) and educational level (HR, 0.50; 95% CI, 0.23–0.97) had significant effect on CRC survival and MetS (HR, 0.95; 95% CI, 0.52–1.5), tumor size (HR, 1.390; 95% CI, 1.237–1.560), family history, age, gender, and smoking had non-significant effect on CRC survival.

Conclusion: MetS could be a prognostic factor for survival in the patients with CRC. The results suggested that effect of MetS was not significant.

Pulse-wave velocity, the ankle-brachial index, and the visceral fat area are highly associated with colorectal adenoma

BACKGROUND

Although both colorectal neoplasms and atherosclerosis may be induced by visceral fat accumulation, no association between these factors has yet been elucidated.

METHODS

Among Japanese participants in our colonoscopic screening and annual surveillance programs, asymptomatic subjects were investigated. Visceral fat area was measured by computed tomography, and the ankle-brachial index and pulse-wave velocity (markers of systemic atherosclerosis) were also estimated. Colorectal findings during screening were investigated in association with these parameters.

RESULTS

Nine hundred and seven subjects (males: 71.9%; mean age: 57.3±8.7 years) were enrolled. Colorectal adenomas were identified during colorectal screening of 407 subjects (44.9%). The prevalence of all colorectal adenoma and advanced neoplasia increased with an elevated pulse-wave velocity from 32.2% (advanced neoplasia, 2.6) to 62.1% (8.4%) in higher quartiles (p<0.001 and p=0.003). The risk of advanced neoplasia was higher in subjects with an abnormal ankle-brachial index (33% vs. 4.6%, p<0.001). Upon multivariate analysis, visceral fat area and pulse-wave velocity were associated with all adenoma, and the ankle-brachial index with advanced neoplasia.

CONCLUSIONS

The risk of colorectal adenoma was strongly associated with visceral fat area and markers of atherosclerosis. Colorectal adenoma and atherosclerosis may share a common pathogenesis and the same populations are at high-risk.

The risk of colonic adenomas and colonic cancer in obesity

Increasing body fatness has been associated with an increased burden from colorectal cancer. An increased susceptibility spanning the entire continuum from precancerous adenomatous polyps to the development of colorectal cancer, poor outcome with treatment, and reduced survival when compared to those with normal body weight has been described. It is unknown which age period and which degree and duration of excess weight are associated with increased colorectal cancer risk. It is uncertain whether weight loss can reverse this risk. If it can, how long will the new lower or normal weight be maintained to effect enduring risk reduction? Furthermore, it is controversial whether the increased burden of colorectal cancer warrants earlier and/or more frequent screening for obese persons. This article reviews the relationship between obesity and colorectal neoplasia, explores the postulated mechanism of carcinogenesis, discusses interventions to reduce the burden of disease, and suggests future directions of research.

Sedentary behavior is associated with colorectal adenoma recurrence in men

PURPOSE

The association between physical activity and colorectal adenoma is equivocal. This study was designed to assess the relationship between physical activity and colorectal adenoma recurrence.

METHODS

Pooled analyses from two randomized, controlled trials included 1,730 participants who completed the Arizona Activity Frequency Questionnaire at baseline, had a colorectal adenoma removed within 6 months of study registration, and had a follow-up colonoscopy during the trial. Logistic regression modeling was employed to estimate the effect of sedentary behavior, light-intensity physical activity, and moderate-vigorous physical activity on colorectal adenoma recurrence.

RESULTS

No statistically significant trends were found for any activity type and odds of colorectal adenoma recurrence in the pooled population. However, males with the highest levels of sedentary time experienced 47% higher odds of adenoma recurrence. Compared to the lowest quartile of sedentary time, the ORs (95% CIs) for the second, third, and fourth quartiles among men were 1.23 (0.88, 1.74), 1.41 (0.99, 2.01), and 1.47 (1.03, 2.11), respectively (p(trend) = 0.03). No similar association was observed for women.

CONCLUSIONS

This study suggests that sedentary behavior is associated with a higher risk of colorectal adenoma recurrence among men, providing evidence of detrimental effects of a sedentary lifestyle early in the carcinogenesis pathway.

Linking lifestyle factors and insulin resistance, based on fasting plasma insulin and HOMA-IR in middle-aged Japanese men: a cross-sectional study

OBJECTIVE

Insulin resistance (IR) is regarded as one of the earliest features of many metabolic diseases, and major efforts are aimed at improving insulin function to confront this issue. The aim of this study was to investigate the relationship of body mass index (BMI), cigarette smoking, alcohol intake, physical activity, green tea and coffee consumption to IR.

METHODS

We performed a cross-sectional study of 1542 male self defense officials. IR was defined as the highest quartile of the fasting plasma insulin (≥ 50 pmol/L) or the homeostasis model assessment-estimated IR (HOMA-IR ≥ 1.81). An unconditional logistic model was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for the association between IR and influential factors. Stratified analysis by obesity status (BMI < 25 kg/m(2), non-obese; ≥ 25 kg/m(2), obese) was performed.

RESULTS

IR was significantly positively related to BMI and glucose tolerance, negatively related to alcohol use. Independent of obesity status, significant trends were observed between IR and alcohol use. Drinking 30 mL or more of ethanol per day reduced IR by less than 40%. Strong physical activity was associated with decreased risk of IR based on fasting plasma insulin only in the obese. Coffee consumption was inversely associated with the risk of IR based on HOMA-IR in the non-obese group.

CONCLUSION

Higher coffee consumption may be protective against IR among only the non-obese. Further studies are warranted to examine the effect modification of the obesity status on the coffee-IR association.

The role of obesity in gastrointestinal cancer: evidence and opinion

There is increasing recognition of the impact of being overweight and obese on the development of cancers at diverse sites including the gastrointestinal tract. Large epidemiological studies indicate that up to 14% of tumours may be related to obesity. Pathophysiological mechanisms underpinning this association are not well understood and so are discussed in this review.

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.

Adult weight change and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

AIM

Weight change during adult life may reflect metabolic changes and influence colorectal cancer (CRC) development, but such role is not well established. We aimed to explore the association between adult weight change (from age 20 to 50) and CRC risk. In particular, we investigated differences according to colon and rectal cancer, sex and measures of attained adiposity.

METHODS

We included 201,696 participants from six participating countries in the European Prospective Investigation into Cancer and Nutrition (1992-2010). During a mean follow-up of 11.2 years 2384 (1194 in men and 1190 in women) incident CRC cases occurred. Cox proportional hazard models adjusted for body mass index at age 20 and lifestyle factors at study recruitment were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After multivariable adjustment, each kg of weight gained annually from age 20 to 50 was associated with a 60% higher risk of colon cancer (95% CI 1.20-2.09), but not rectal cancer (HR 1.13, 95% CI 0.79-1.62, P(interaction)=0.04). The higher risk of colon cancer was restricted to people with high attained waist circumference at age 50 (HR 1.82, 95%CI 1.14-2.91, P(interaction)=0.02). Results were not different in men and women (P(interaction)=0.81).

CONCLUSION(S)

Adult weight gain, as reflected by attained abdominal obesity at age 50, increases colon cancer risk in both men and women. These data underline the importance of weight management and metabolic health maintenance in early adult life years for colon cancer prevention.

Risk of colonic cancer is not higher in the obese Lep(ob) mouse model compared to lean littermates

Epidemiological data suggest that obesity increases the risk of colorectal cancer in humans. Given that diet-induced obesity mouse models verified the epidemiological data, the present study aimed to determine whether obese C57BL/6J-Lep(ob) male mice (a different obesity in vivo model) were at greater risk of colonic cancer than their lean male littermates. Risk of colonic tumorigenesis was assessed by numbers of aberrant crypts, aberrant crypt foci and colonic tumors. Proliferation of the colonic epithelia was assessed histochemically following administration of BrdU. Availability of the procarcinogen, azoxymethane (AOM) to target tissues was assessed by quantifying via HPLC plasma AOM concentrations during the 60 min period following AOM injection. When obese and lean mice were injected with azoxymethane (AOM) at doses calculated to provide equivalent AOM levels per kg lean body mass, obese animals had significantly fewer aberrant crypts/colon and fewer aberrant crypt foci/colon than the lean animals. Tumors were identified in the colonic mucosa of lean (4 tumors in 14 mice) but not obese (0 tumors in 15 mice) mice. Colonic cell proliferation was not significantly different for obese and lean mice. Because these results were unexpected, plasma AOM concentrations were measured and were found to be lower in the obese than lean mice. When plasma AOM levels were comparable for the lean and obese mice, the Lep(ob) mice continued to have significantly fewer aberrant crypt foci/colon than the lean mice, but differences were not statistically different for aberrant crypts/colon. Interestingly, obese Lep(ob) mice did not exhibit increased risk of colonic cancer as expected. Instead, Lep(ob) mice exhibited equivalent or lower risk of colon cancer when compared to the lean group. These results taken together with in vivo results from diet-induced obesity studies, imply that leptin may be responsible for the increased risk of colon cancer associated with obesity.

Physical activity and other lifestyle factors in relation to the prevalence of colorectal adenoma: a colonoscopy-based study in asymptomatic Koreans

PURPOSE

To evaluate physical activity and other lifestyle risk factors in relation to the prevalence of colorectal adenomas in asymptomatic Koreans.

METHODS

A total of 1,526 asymptomatic subjects who underwent a colonoscopy were enrolled. Lifestyle factors such as physical activity and smoking data were obtained using a questionnaire. The subjects were grouped into three exposure levels by tertiles of metabolic equivalent hours per week. We evaluated the risk factors in subjects with adenomas by risk stratification (low-risk adenoma group vs. high-risk adenoma group) and by anatomic location (proximal colon, distal colon, rectum, and multiple locations). The high-risk adenoma group was defined as subjects with advanced adenomas or multiple (≥ 3) adenomas.

RESULTS

A total of 456 participants had colorectal adenomas, and 861 had no polyps. In multivariate analyses, higher levels of physical activity were associated with a significantly decreased risk of colorectal adenomas (OR = 0.56, 95% CI 0.40-0.79). This inverse association was stronger for the risk of high-risk adenomas (OR = 0.39, 95% CI 0.21-0.73) than for low-risk adenomas (OR = 0.62, 95% CI 0.43-0.89). The negative relation of physical activity was significant for distal colon adenomas (OR = 0.54, 95% CI 0.30-0.95) and the adenomas with multiple locations (OR = 0.39, 95% CI 0.21-0.72).

CONCLUSIONS

Increased physical activity is associated with a reduced prevalence of colorectal adenomas. The inverse association between physical activity and adenoma was stronger for the risk of advanced or multiple adenomas.

Body mass index at different adult ages, weight change, and colorectal cancer risk in the National Institutes of Health-AARP Cohort

The authors investigated the relations of body mass index at different ages and adult weight change to incident colorectal cancer risk in the prospective National Institutes of Health-AARP Diet and Health Study (1995-1996), using a subcohort with repeated recall weights (273,679 participants; mean baseline age = 62.8 years). During 2,509,662 person-years follow-up, 4076 incident colorectal cancers were ascertained. For men, an increased risk of colon cancer but not rectal cancer was associated with body mass index at baseline age (per 5-kg/m(2) increase, hazard ratio (HR) = 1.18, 95% confidence interval (CI): 1.11, 1.25), at age 50 years (HR = 1.18, 95% CI: 1.10, 1.26), and at age 35 years (HR = 1.16, 95% CI: 1.07, 1.25) but less so at age 18 years. Weight gained between the ages of 18 and 35 years and between 18 years of age and the baseline age was associated with an increased risk of colon cancer in men (per 0.5-kg/year increase, HR = 1.18, 95% CI: 1.11, 1.25 and HR = 1.29, 95% CI: 1.16, 1.56, respectively). For women, relations throughout were weaker than those observed for men. These findings suggest that weight gains during early to middle adulthood have important influences on colon cancer risk, especially in men.

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.

Abdominal obesity and endometrial cancer in egyptian females with postmenopausal bleeding

Endometrial cancer is the most common type of female genital tract malignancies. We intended to assess the relation between different measures of obesity and the risk to develop endometrial cancer in Egyptian females with postmenopausal bleeding (PMB). The study was conducted in Alexandria, Egypt and included all postmenopausal females presenting to the University Hospital of Gynecology and Obstetrics with PMB within the study period (from January 1 to September 30). A questionnaire was completed, and data about anthropometric measurements including weight, height, and waist circumference were collected. Vaginal sonography, dilatation and curettage, and pathological examination were done by experts for all participants. Endometrial cancer was diagnosed in 38% of females presenting with PMB. Using ROC curve analysis, only the measure of abdominal obesity (waist circumference) showed significant accuracy in predicting endometrial cancer (area = 0.63, P < .05). The best cutoff point that maximizes accuracy was 88 cm. Body mass index (≥30 vs. ≤30) showed no significant relation (OR = 1.1, 95%CI 0.5-2.3), and the ratio between upper and lower body obesity (W/H ratio) showed border line significant relation (OR = 2, 95% CI 1-4.1), whereas waist circumference (≥88 vs. ≤88 cm) showed strikingly high OR (OR = 13.6, 95%CI 4-46.6). The risk of abdominal obesity on endometrial cancer remains very high (OR = 15.8, 95%CI 4.1-60.9) even after adjustment, in a logistic model, for other risk factors such as age at presentation, age at menarche, age at menopause, family history of malignancy, and gravidity. Abdominal obesity (waist circumference >88 cm) is the best measure of obesity to be used in predicting the risk of endometrial cancer in Egyptian females with PMB.

Korean type 2 diabetes patients have multiple adenomatous polyps compared to non-diabetic controls

We tested the correlation between diabetes and aggressiveness of colorectal polyps in diabetic patients and matched non-diabetic controls. We retrospectively studied 3,505 type 2 diabetes (T2DM) patients without gastrointestinal symptoms who underwent colonoscopy for colorectal cancer at Samsung Medical Center, Seoul, Korea from August 1995 to August 2009. We matched 495 non-diabetic subjects with colon polyps to the diabetic patients in whom polyps were detected by year of colonoscopy, age, sex and body mass index (BMI). Among the 3,505 T2DM patients screened, 509 were found to have 1,136 colon polyps. Those with diabetes had a greater proportion of adenomatous polyps (62.8% vs 53.6%) compared to the control. Multivariate logistic regression analysis identified DM, male gender, age and BMI as independent risk factors for multiple polyps (more than three polyps). Polyp multiplicity in diabetic patients was significantly associated with male gender (OR 2.360, P = 0.005), age (OR 1.033, P = 0.005) and BMI (OR 1.077, P = 0.028). Neither aspirin nor metformin use affected either size or number of polyps in diabetic patients. Male patients older than 65 yr with T2DM and BMI greater than 25 have increased risk for multiple adenomatous polyps and should be screened with colonoscopy to prevent colorectal cancer.

The association of serum lipids with the histological pattern of rectosigmoid adenoma in Taiwanese adults

BACKGROUND

The mortality rate of colorectal cancer ranks third behind lung and hepatic cancer in Taiwan. Colorectal cancer mostly arises from adenomatous polyps of left colon. The aim of our study was to examine the association of serum lipids with the histological pattern of rectosigmoid adenoma.

METHODS

There were 2,506 eligible examinees aged 20 and above who underwent sigmoidoscopy as a screening examination in National Cheng Kung University Hospital between January 2003 and October 2006. They were classified into three groups: tubular adenoma (333 subjects), villous-rich (tubulovillous/villous) adenoma (53 subjects) and normal (2,120 subjects). We defined high total cholesterol (TC) as a level ≧200 mg/dl, low high-density lipoprotein cholesterol (HDL-C) as a level <40 mg/dL, and high triglyceride (TG) as a level ≧200 mg/dl according to the third report of the National Cholesterol Education Program expert panel on detection, evaluation, and treatment of high blood cholesterol in adults. Adenoma histology was classified as tubular, tubulovillous and villous according to the proportion of villous part.

RESULTS

Among the study population, 333 subjects (13.3%) had tubular adenomas and 53 subjects (2.1%) had villous-rich adenomas. The odds ratio (OR) for villous-rich adenoma in subjects with TG≧200 mg/dL compared to those with TG < 200 mg/dL was 3.20 (95% confidence interval [CI]:1.71-6.01), after adjusting for age, gender, general obesity, central obesity, diabetes, hypertension, smoking, and alcohol consumption. If further taking high TC and low HDL-C into consideration, the OR was 4.42 (95% CI:2.03-9.63).

CONCLUSIONS

Our study showed that subjects with high serum TG tended to have a higher risk of tubulovillous/villous adenoma in rectosigmoid colon. Therefore, reducing the serum TG level might be one method to prevent the incidence of colorectal cancer.

Physical activity and risk of colon adenoma: a meta-analysis

BACKGROUND

Little evidence is available on the relation of physical activity with colon adenomas, a colon cancer precursor.

METHODS

We conducted a systematic literature review and meta-analysis of published studies (in English) through April 2010, examining physical activity or exercise and risk or prevalence of colon adenoma or polyp. Random effects models were used to estimate relative risks (RRs) and corresponding confidence intervals (CIs). A total of 20 studies were identified that examined the association and provided RRs and corresponding 95% CIs.

RESULTS

A significant inverse association between physical activity and colon adenomas was found with an overall RR of 0.84 (CI: 0.77-0.92). The association was similar in men (RR=0.81, CI: 0.67-0.98) and women (RR=0.87, CI: 0.74-1.02). The association appeared slightly stronger in large/advanced polyps (RR=0.70, CI: 0.56-0.88).

CONCLUSION

This study confirms previous reports of a significant inverse association of physical activity and colon adenoma, and suggests that physical activity can have an important role in colon cancer prevention.

Anthropometric factors in adulthood and risk of colorectal adenomas: The French E3N-EPIC prospective cohort

Anthropometric factors have been associated with colorectal cancer and adenomas but with conflicting results in women or regarding adenoma characteristics. The authors aimed to explore associations between anthropometric factors (height, weight, body mass index, waist and hip circumferences, and weight changes) and adenoma risk. They analyzed the 17,391 women of the French Etude épidémiologique des femmes de la Mutuelle Générale de l'Education Nationale (E3N)-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort who underwent a colonoscopy during follow-up (1993-2002), including 1,408 who developed a first colorectal adenoma. In Cox multivariate proportional hazard regression models, obesity was associated with an increased colorectal adenoma risk (hazard ratio = 1.53, 95% confidence interval: 1.21, 1.94). This association was restricted to left colon adenomas (P(homogeneity) = 0.05 and 0.01 for colon vs. rectum and right vs. left colon, respectively), with a dose-effect relation observed from 22 kg/m². A high waist circumference was also associated with left colon adenoma risk (hazard ratio = 1.81, 95% confidence interval: 1.36, 2.41). Mean weight gain over 0.5 kg/year was associated with a 23% increased colorectal adenoma risk. Associations did not differ between advanced and nonadvanced adenomas. In conclusion, study findings suggest that obesity and weight gain are associated with early colorectal carcinogenesis in women, and specifically regarding the distal colon.

The comparison of the clinical manifestations and risk factors of colorectal cancer and adenomas: results from a colonoscopy-based study in southern Chinese

BACKGROUND AND AIMS

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors in the world. This study aimed to compare the clinical manifestations and risk factors of CRC and adenomas in native patients of Guangzhou.

METHODS

Patients who underwent colonoscopy for the first time at Nanfang Hospital between July 2008 and July 2009 were recruited. Data on demographic information, main clinical manifestations, results of endoscopies and pathology, and possible risk factors of colorectal tumor were collected. Chi-square test and logistic regression were used to compare the clinical characteristics and risk factors for CRC and adenomas.

RESULTS

Hematochezia and body weight loss were more frequent in proximal and distal CRC groups, respectively (P ≤  0.05). Older age [odds ratio (OR), 1.079; 95% confidence interval (CI), 1.065-1.093], smoking status (OR, 1.712; 95% CI, 1.158-2.531), BMI =18.5-24.9 and  ≥ 25.0 (OR, 2.384; 95% CI, 1.250-4.549; OR, 2.162; 95% CI, 1.044-4.478, respectively) were significant risk factors for advanced adenoma, while female (OR, 0.638; 95% CI, 0.429-0.949) and using aspirin (OR, 0.188; 95% CI, 0.042-0.845) were significant protective factors. Hyperlipemia (OR, 0.109; 95% CI, 0.013-0.886) was identified as a protective factor for proximal CRC. Smoking (OR, 1.717; 95% CI, 1.093-2.696), drinking (OR, 1.817; 95% CI, 1.145-2.883), DM history (OR, 2.204; 95% CI, 1.044-4.652) were identified as independent risk factors for distal CRC, and using aspirin (OR, 0.190; 95% CI, 0.043-0.840) was a protective factor. Drinking (OR, 3.288; 95% CI, 1.546-6.994; OR, 1.862; 95% CI, 1.037-3.343, respectively) was an independent risk factor for both poorly to moderately differentiated CRC and well-differentiated CRC. Besides, DM (OR, 3.761; 95% CI, 1.615-8.762) and hypertension (OR, 0.384; 95% CI, 0.178-0.828) were identified as independent risk factor and protective factor for well-differentiated CRC, respectively.

CONCLUSIONS

Hematochezia and body weight loss were representative manifestations for distal and proximal CRC, respectively. For southern Chinese the most important influential factors for colorectal tumor are age, smoking, drinking, nutritional state, DM, hypertension, and the use of aspirin.

Clinical study on the correlation between metabolic syndrome and colorectal carcinoma

BACKGROUND

Although metabolic syndrome (MS) has received a lot of attention in recent years, the correlation between MS and colorectal carcinoma is still not very clear. This study aims at exploring the relationship between MS and colorectal carcinoma.

METHODS

Data was collected from 507 cases of colorectal carcinoma and 507 cases of healthy patients between January 2002 and March 2007 to establish the database. The patients with colorectal cancer were divided into two groups based on the presence of MS. Multivariate analysis of these data for the overall survival and recurrence was performed with the Cox proportional hazard model. Variables examined by multivariate analysis were sex , age, location, histotype, differentiation, tumour, node, metastasis (TNM) stage, the number of lymph nodes detected, etc.

RESULTS

The existence of MS in the colorectal carcinoma group was clearly more than that in the control group. The existence of two to four types of abnormal metabolic diseases was significantly more in the colorectal cancer group than in the control group. MS is one of the important elements that can independently influence the survival (odds ratio (OR) = 1.501, 95% confidence interval (CI) = 1.057-2.131) and have the highest risk with worse survival compared with other parameters.

CONCLUSION

There is a close relationship between MS and colorectal carcinoma, and MS is a significantly independent element that influences the survival of the colorectal carcinoma. Decreasing the incidence of MS maybe play a role in improving therapeutic efficacy and prognosis of the cancer.

Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

BACKGROUND

Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene), a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established.

METHODS

We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity) and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis.

RESULTS

Resveratrol (100-150 microM) exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway.

CONCLUSIONS

For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and activation of p53, suggesting its potential role as a chemotherapeutic agent.

Obesity and gastrointestinal cancer

BACKGROUND

There is emerging evidence of a strong association between obesity and gastrointestinal cancer. This review summarizes the evidence from an epidemiological and pathophysiological perspective.

METHODS

Relevant medical literature was identified from searches of PubMed and references cited in appropriate articles were identified. Selection of articles was based on peer review, journal and relevance.

RESULTS

Numerous epidemiological studies consistently identified an increased risk of developing oesophageal adenocarcinoma and colorectal carcinoma in the obese. The association between obesity and other gastrointestinal malignancies was less robust. Sex seems important with respect to cancer risk. Adipose tissue, particularly viscerally located fat, is metabolically active and exerts systemic endocrine effects. Putative pathophysiological mechanisms linking obesity and carcinogenesis include the insulin-like growth factor axis, adipocytokines and sex steroids.

CONCLUSION

A better understanding of the mechanisms that link obesity and cancer may uncover targets for intervention. Tackling obesity may result in a reduction in the incidence in addition to mortality of certain cancers in future.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Physical activity and gastrointestinal cancer prevention

Colorectal cancer is the third most common cancer globally and is a leading cause of cancer death. Gastric cancer contributes significantly to the global cancer burden, particularly in low- and middle-income countries. We reviewed the literature for studies on physical activity or exercise and colon, rectal, and gastric cancers as well as colonic adenomatous polyps. We identified 52 studies of colon cancer, 31 studies of rectal cancer, 23 studies of colon polyps, and 16 studies of gastric cancer. Of the 52 studies of physical activity and colon cancer, 37 found a statistically significant association between increased levels of physical activity and decreased colon cancer risk in at least one comparison. Accumulated evidence suggests that physical activity is associated with a 25% reduction in colon cancer risk. In line with previous reports, we found no indication that the association was more pronounced for occupational versus recreational physical activity, with both resulting in a risk reduction of about 22%. Evidence for other domains of physical activity (i.e., transportation or household physical activity) is limited. Evidence is emerging that individuals who are consistently active across the lifetime may obtain greater risk reductions than those who are only active in recent years. Despite consistent associations with colon cancer, evidence is more limited though suggestive that physical activity reduces risk of colon adenomas or adenoma recurrence. There is clear evidence that physical activity is not associated with rectal or gastric cancers.

Visceral fat volume and the prevalence of colorectal adenoma

Few epidemiologic investigations of visceral adiposity and colorectal neoplasms have attempted the direct quantification of visceral fat. The authors measured visceral fat volume among middle-aged and elderly Japanese men and women who underwent colonoscopy and positron emission tomography/computed tomography for cancer screening in Tokyo, Japan, between February 2004 and February 2005, and examined the association between visceral adiposity and colorectal adenoma in 1,205 eligible subjects. Odds ratios and 95% confidence intervals for colorectal adenoma were estimated by using an unconditional logistic regression model after adjustment for potential confounders. Despite its high correlation with body mass index, visceral fat volume was associated with the prevalence of colorectal adenoma independently of body mass index in both sexes. After further adjustment for body mass index, the odds ratio of colorectal adenoma for the highest compared with the lowest quartile of visceral fat volume was 1.58 (95% confidence interval: 1.11, 2.24) for men and women combined. Conversely, body mass index was unlikely to modify the association between visceral fat volume and colorectal adenoma (P(interaction) = 0.39). These findings add to accumulating evidence that visceral adiposity exerts an important influence on the pathogenesis of colorectal neoplasms. The mechanisms of this potential association between visceral adiposity and colorectal carcinogenesis warrant further investigation.

Relation between obesity and adenomatous polyps of the large bowel

BACKGROUND

We compared the prevalence of colorectal adenoma (polyps) in men and women and examined the role of body mass index (BMI) on polyp risk according to patient age and gender.

METHODS

The risk of developing colorectal polyps was studied in 15 380 subjects (7155 men and 8225 women) who underwent colonoscopy for the first time from April 1998 to March 2006 at our 'Human Dry Dock', which is the check-up service provided in Japan. Eligible subjects were 20-86 years old (mean age +/- SD, 47.3 +/- 8.5) and were free of invasive cancer, hyperplastic polyps and familial polyposis. Polyps were found in 1590 subjects (1062 men and 528 women). The odds ratio (OR) of detection of polyps in relation to obesity was determined in all cases by multivariate logistic regression analysis after making an adjustment for gender and age.

RESULTS

The OR of polyp detection in obese subjects (BMI >or= 25) versus non-obese subjects (BMI < 25, OR = 1) was 1.34 (P < 0.001) in men and 1.13 (P = 0.26) in women. As the BMI increased in increments of one, the OR in men increased significantly to 1.01 (P < 0.001), whereas the OR in women was unchanged at 1.00 (P = 0.23), which was without significance.

CONCLUSIONS

We conclude that obesity in men is a risk factor for the development of polyps. These results must be confirmed by additional epidemiological studies.

Adiposity in relation to colorectal adenomas and hyperplastic polyps in women

OBJECTIVE

To examine whether BMI is independently related to colorectal adenomas and hyperplastic polyps.

METHODS

We conducted a cross-sectional study among 1,420 asymptomatic women aged 40-79 years who had undergone complete colonoscopy. Logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI) of adenomas and hyperplastic polyps.

RESULTS

We identified 953 women (67.1%) with no polyps, 292 (20.6%) with adenomas, and 175 (12.3%) with hyperplastic polyps. Among those with polyps, 75 women (5.3% of total women) were classified as having both adenomas and hyperplastic polyps. After adjusting for potential risk factors for colorectal cancer, BMI was related to increased risk of adenomas (OR comparing obese to normal weight women = 1.57; 95% CI = 1.07-2.29). Further, BMI was associated with enhanced risk of hyperplastic polyps (OR = 3.76; 95% CI = 2.35-6.01) and the combination of adenomas and hyperplastic polyps (OR = 2.84; 95% CI = 1.41-5.72).

CONCLUSIONS

Excess body mass is positively related to colorectal adenomas and hyperplastic polyps, particularly when both kinds of polyps are present in combination. Future studies should continue to delineate the possible differences in potential risk factors between colorectal adenomas and hyperplastic polyps. Such work should help further elucidate the possible causes of colorectal cancer.

Adiposity in relation to colorectal adenomas and hyperplastic polyps in women

OBJECTIVE

To examine whether BMI is independently related to colorectal adenomas and hyperplastic polyps.

METHODS

We conducted a cross-sectional study among 1,420 asymptomatic women aged 40-79 years who had undergone complete colonoscopy. Logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI) of adenomas and hyperplastic polyps.

RESULTS

We identified 953 women (67.1%) with no polyps, 292 (20.6%) with adenomas, and 175 (12.3%) with hyperplastic polyps. Among those with polyps, 75 women (5.3% of total women) were classified as having both adenomas and hyperplastic polyps. After adjusting for potential risk factors for colorectal cancer, BMI was related to increased risk of adenomas (OR comparing obese to normal weight women = 1.57; 95% CI = 1.07-2.29). Further, BMI was associated with enhanced risk of hyperplastic polyps (OR = 3.76; 95% CI = 2.35-6.01) and the combination of adenomas and hyperplastic polyps (OR = 2.84; 95% CI = 1.41-5.72).

CONCLUSIONS

Excess body mass is positively related to colorectal adenomas and hyperplastic polyps, particularly when both kinds of polyps are present in combination. Future studies should continue to delineate the possible differences in potential risk factors between colorectal adenomas and hyperplastic polyps. Such work should help further elucidate the possible causes of colorectal cancer.

Components of metabolic syndrome and metachronous colorectal neoplasia

BACKGROUND

The consistent association between obesity and colorectal cancer is thought to be explained by metabolic disturbances common, but not exclusive, to the obese.

METHODS

We assessed the relation between metachronous neoplasia and the components of metabolic syndrome (MetS) as defined by the National Cholesterol Education Program's Adult Treatment Panel III in 2,392 participants of two previously conducted chemoprevention trials. Waist circumference, fasting plasma glucose, trigylcerides, high-density lipoprotein, and systolic and diastolic blood pressure were measured at baseline.

RESULTS

MetS classification was associated with increased odds of metachronous neoplasia among women [odds ratio (OR), 1.37; 95% confidence interval (95% CI), 1.01-1.85] but not among men (OR, 0.99; 95% CI, 0.81-1.21). High waist circumference in men (OR, 1.41; 95% CI, 1.15-1.72) and women (OR, 1.41; 95% CI, 1.05-1.90) and elevated fasting glucose in women (OR, 1.46; 95% CI, 1.09-1.96), as defined by Adult Treatment Panel III cutpoints, were associated with increased odds, whereas none of the other criteria were independently associated with metachronous neoplasia. When each trait was evaluated using quartiles, elevated glucose among women and large waist circumference among men were significantly associated with metachronous lesions. Exploratory analysis of waist circumference and fasting glucose suggested an interaction, where only the combination of large waist circumference and elevated glucose conferred significant increased odds of metachronous neoplasia among both men (OR, 1.36; 95% CI, 1.04-1.78; P(interaction) = 0.08) and women (OR, 1.83; 95% CI, 1.26-2.67; P(interaction) = 0.12).

CONCLUSIONS

These results suggest that, of the specific components of MetS, those that capture impaired glucose uptake increased the odds of metachronous neoplasia.

Association between body mass index and colorectal neoplasia at follow-up colonoscopy: a pooling study

A direct relation between body mass index (BMI) and risk of colorectal adenomas and cancer has been reported, but few studies have had adequate sample size for conducting stratified analyses by sex, family history, colorectal subsite, or features of metachronous lesions. Data from 8,213 participants in 7 prospective studies of metachronous colorectal adenomas were pooled to assess whether the association between BMI and metachronous neoplasia varied by these factors. A statistically significant direct association between BMI and the odds of nonadvanced adenomas (P(trend) < 0.001) was observed, while the relation for advanced adenomas was of marginal significance (P(trend) < 0.07). In sex-stratified analyses, obesity was statistically significantly associated with the odds of any metachronous lesion among men (odds ratio = 1.36, 95% confidence interval: 1.17, 1.58) but not among women (odds ratio = 1.10, 95% confidence interval: 0.89, 1.37). The associations with BMI appeared to be limited to proximal neoplasia, with statistically significant results for BMI and proximal (P(trend) < 0.001), but not distal (P(trend) < 0.85), neoplasia. Exploratory analyses indicated that BMI was significantly related to most histologic characteristics of metachronous adenomas among men but not among women. Our results provide further support for the association between BMI and metachronous colorectal adenomas, particularly among men, thereby indicating that body size may affect colorectal carcinogenesis at comparatively early stages.

An association between colonic adenoma and abdominal obesity: a cross-sectional study

BACKGROUND

Colorectal adenoma is a precursor lesion of colorectal cancer and thus, it is an important target for preventing colorectal cancer. Only a few studies suggest an association between colorectal adenoma and obesity, but results show considerable heterogeneity. In this study, we investigated the association between colorectal adenoma and waist circumference.

METHODS

165 adenoma cases and 365 polyp-free controls with a normal colon were compared in this cross-sectional study. Subjects underwent screening colonoscopy by experienced endoscopists. Demographic data, including smoking habit, were obtained by interview and waist circumference and anthropometric measurements were examined. Dietary intakes were evaluated using a food frequency questionnaire, and abdominal obesity was evaluated by measuring waist circumference. Statistical analysis was performed using SPSS for 13.0.

RESULTS

Age, waist circumference, and BMI were significantly higher in cases than controls. And smokers and men were more prevalent among cases than controls.Among the abdominal obese subjects, 45.6% had 1 or more adenoma, and 9.0% of these had advanced adenoma, whereas among subjects with a normal waist circumference, only 25.7% had 1 or more adenomas. The prevalence of adenoma was higher among abdominal obese group (P < 0.05). Logistic regression analysis showed that abdominal obesity was associated with an increased risk of colorectal adenoma (OR, 2.74; 95% CI, 1.66~4.51 in men, OR, 2.58; 95% CI, 1.08~6.12 in women). These associations persisted even after adjusting for BMI. While BMI was found to be weekly associated with the risk of adenoma among men at the highest BMI levels. However, BMI was not associated with the risk for adenoma after adjusting for waist circumference.

CONCLUSION

Our data suggest that abdominal obesity is associated with an increased risk of colorectal adenoma.

Energy balance, physical activity, and cancer risk

This chapter posits that cancer is a complex and multifactorial process as demonstrated by the expression and production of key endocrine and steroid hormones that intermesh with lifestyle factors (physical activity, body size, and diet) in combination to heighten cancer risk. Excess weight has been associated with increased mortality from all cancers combined and for cancers of several specific sites. The prevalence of obesity has reached epidemic levels in many parts of the world; more than 1 billion adults are overweight with a body mass index (BMI) exceeding 25. Overweight and obesity are clinically defined indicators of a disease process characterized by the accumulation of body fat due to an excess of energy intake (nutritional intake) relative to energy expenditure (physical activity). When energy intake exceeds energy expenditure over a prolonged period of time, the result is a positive energy balance (PEB), which leads to the development of obesity. This physical state is ideal for intervention and can be modulated by changes in energy intake, expenditure, or both. Nutritional intake is a modifiable factor in the energy balance-cancer linkage primarily tested by caloric restriction studies in animals and the effect of energy availability. Restriction of calories by 10 to 40% has been shown to decrease cell proliferation, increasing apoptosis through anti-angiogenic processes. The potent anticancer effect of caloric restriction is clear, but caloric restriction alone is not generally considered to be a feasible strategy for cancer prevention in humans. Identification and development of preventive strategies that "mimic" the anticancer effects of low energy intake are desirable. The independent effect of energy intake on cancer risk has been difficult to estimate because body size and physical activity are strong determinants of total energy expenditure. The mechanisms that account for the inhibitory effects of physical activity on the carcinogenic process are reduction in fat stores, activity related changes in sex-hormone levels, altered immune function, effects in insulin and insulin-like growth factors, reduced free radical generation, and direct effect on the tumor. Epidemiologic evidence posits that the cascade of actions linking overweight and obesity to carcinogenesis are triggered by the endocrine and metabolic system. Perturbations to these systems result in the alterations in the levels of bioavailable growth factors, steroid hormones, and inflammatory markers. Elevated serum concentrations of insulin lead to a state of hyperinsulinemia. This physiological state causes a reduction in insulin-like growth factor-binding proteins and promotes the synthesis and biological activity of insulin-like growth factor (IGF)-I, which regulates cellular growth in response to available energy and nutrients from diet and body reserves. In vitro studies have clearly established that both insulin and IGF-I act as growth factors that promote cell proliferation and inhibit apoptosis. Insulin also affects on the synthesis and biological availability of the male and female sex steroids, including androgens, progesterone, and estrogens. Experimental and clinical evidence also indicates a central role of estrogens and progesterone in regulating cellular differentiation, proliferation, and apoptosis induction. Hyperinsulinemia is also associated with alterations in molecular systems such as endogenous hormones and adipokines that regulate inflammatory responses. Obesity-related dysregulation of adipokines has the ability to contribute to tumorigenesis and tumor invasion via metastatic potential. Given the substantial level of weight gain in industrialized countries in the last two decades, there is great interest in understanding all of the mechanisms by which obesity contributes to the carcinogenic process. Continued focus must be directed to understanding the various relationships between specific nutrients and dietary components and cancer cause and prevention. A reductionist approach is not sufficient for the basic biological mechanisms underlying the effect of diet and physical activity on cancer. The joint association between energy balance and cancer risk are hypothesized to share the same underlying mechanisms, the amplification of chemical mediators that modulate cancer risk depending on the responsiveness to those hormones to the target tissue of interest. Disentangling the connection between obesity, the insulin-IGF axis, endogenous hormones, inflammatory markers, and their molecular interaction is vital.

Waist circumference and insulin resistance: a cross-sectional study of Japanese men

BACKGROUND

Visceral obesity is positively related to insulin resistance. The nature of the relationship between waist circumference and insulin resistance has not been known in Japanese populations. This study examined the relationship between waist circumference and insulin resistance and evaluated the optimal cutoff point for waist circumference in relation to insulin resistance in middle-aged Japanese men.

METHODS

Study subjects included 4800 Japanese men aged 39 to 60 years. Insulin resistance was evaluated by the homeostasis model assessment of insulin resistance (HOMA-IR). The relationship of waist circumference with HOMA-IR was assessed by use of adjusted means of HOMA-IR and odds ratios of elevated HOMA-IR defined as the highest quintile (>or=2.00). Receiver operating characteristics (ROC) curve analysis using Youden index and the area under curve (AUC) was employed to determine optimal cutoffs of waist circumference in relation to HOMA-IR.

RESULTS

Adjusted geometric means of HOMA-IR and prevalence odds of elevated HOMA-IR were progressively higher with increasing levels of waist circumference. In the ROC curve analysis, the highest value of Youden index was obtained for a cutoff point of 85 cm in waist circumference across different values of HOMA-IR. Multiple logistic regression analysis also indicated that the AUC was consistently the largest for a waist circumference of 85 cm.

CONCLUSION

Waist circumference is linearly related to insulin resistance, and 85 cm in waist circumference is an optimal cutoff in predicting insulin resistance in middle-aged Japanese men.

Lifestyle, genes, and cancer

It is estimated that almost 1.5 million people in the USA are diagnosed with cancer every year. However, due to the substantial effect of modifiable lifestyle factors on the most prevalent cancers, it has been estimated that 50% of cancer is preventable. Physical activity, weight loss, and a reduction in alcohol use can strongly be recommended for the reduction of breast cancer risk. Similarly, weight loss, physical activity, and cessation of tobacco use are important behavior changes to reduce colorectal cancer risk, along with the potential benefit for the reduction of red meat consumption and the increase in folic acid intake. Smoking cessation is still the most important prevention intervention for reducing lung cancer risk, but recent evidence indicates that increasing physical activity may also be an important prevention intervention for this disease. The potential benefit of lifestyle change to reduce prostate cancer risk is growing, with recent evidence indicating the importance of a diet rich in tomato-based foods and weight loss. Also, in the cancers for which there are established lifestyle risk factors, such as physical inactivity for breast cancer and obesity for colorectal cancer, there is emerging information on the role that genetics plays in interacting with these factors, as well as the interaction of combinations of lifestyle factors. Integration of genetic information into lifestyle factors can help to clarify the causal relationships between lifestyle and genetic factors and assist in better identifying cancer risk, ultimately leading to better-informed choices about effective methods to enhance health and prevent cancer.

Genetic polymorphisms of CYP2E1 and risk of colorectal adenomas in the Self Defense Forces Health Study

CYP2E1 is an enzyme involved in the metabolism of N-nitrosamines and other carcinogenic substances. Functional RsaI and 96-bp insertion polymorphisms in 5'-flanking region have drawn interest in relation to the risk of colorectal cancer. We investigated the relation of these genetic polymorphisms and colorectal adenoma, a well-established precursor lesion of colorectal cancer. Subjects were 455 cases of colorectal adenomas and 1,052 controls of normal colonoscopy among men receiving a preretirement health examination in the Self Defense Forces. Genotypes were determined by either PCR-RFLP or PCR method. Statistical adjustment was made for smoking, alcohol use, body mass index, physical activity, and others. Individuals with RsaI c2 allele showed a decreased risk of proximal colon adenomas; adjusted odds ratios (95% confidence interval) of proximal and distal adenomas for the c1/c2 or c2/c2 genotype versus c1/c1 was 0.61 (0.41-0.88) and 0.95 (0.71-1.27), respectively. CYP2E1 96-bp insertion allele was associated with an increased risk of large (> or = 5 mm) adenomas; adjusted odds ratios (95% confidence interval) of large and small adenomas for having at least one insertion allele were 1.41 (1.03-1.94) and 0.94 (0.71-1.25), respectively. A suggestive effect modification was noted for alcohol consumption on the association between RsaI polymorphism and proximal adenomas (P(interaction) = 0.09) as well as on the association between 96-bp insertion and large adenomas (P(interaction) = 0.05). These findings indicate that variation in activity and inducibility of CYP2E1 contribute to the development of colorectal carcinogenesis.

Cholelithiasis is a risk factor for colorectal adenoma

OBJECTIVES

Postcholecystectomy patients show moderate risk of colorectal cancer. However, few studies have investigated the relationship between cholelithiasis and colorectal adenoma. We examined this possibility through a combination of colonoscopy and ultrasonography in asymptomatic Japanese.

METHODS

We reviewed a subgroup of subjects drawn from a prospective annual colonoscopy screening survey. Subjects who underwent both ultrasonography and colonoscopy, and completed a questionnaire regarding lifestyle habits were entered. We investigated whether subjects with cholelithiasis or a previous cholecystectomy showed an increased risk of colorectal adenoma, as compared with subjects with normal gallbladders.

RESULTS

Data of 4,458 subjects (men 3,053, women 1,405, mean age +/- SD 46.1 +/- 8.62 yr) were analyzed. Cholelithiasis was detected in 206 subjects, 4,189 subjects had normal gallbladders, and 63 subjects had cholecystectomies. The prevalence of colorectal adenoma was 29.6% (61/206) in subjects with cholelithiasis, which was significantly higher when compared with normal subjects, with a prevalence of 17.7% (741/4,189, P < 0.001). In cholecystectomy patients, only 15.9% (10/63) developed colorectal adenomas, which was not significantly different from the control group. In a multivariate analysis controlling for sex, age, family history of colorectal cancer, alcohol, smoking, and body mass index, cholelithiasis was shown to be an independent risk factor for colorectal adenoma (adjusted OR 1.57, 95% CI 1.14-2.18). Cholelithiasis was strongly associated with multiple (> or = 3 lesions, adjusted OR 2.39, 95% CI 1.21-4.72) and left-sided colorectal adenomas (adjusted OR 1.82, 95% CI 1.28-2.59).

CONCLUSIONS

Cholelithiasis is a risk factor for colorectal adenoma.