Increased risk of 'high-risk' colorectal adenomas in overweight men

Bowel-cleansing efficacy of the 1L polyethylene glycol-based bowel preparation NER1006 (PLENVU) in patient subgroups in two phase III trials

BACKGROUND

Adequate bowel preparation prior to colonoscopy is essential for visualization of the colonic mucosa to maximize adenoma and polyp detection. The risk of inadequate bowel cleansing is heightened if the patient is older, male, overweight, and has comorbidities, such as diabetes. This post hoc analysis of the combined MORA and NOCT clinical trials explores the efficacy of evening/morning split-dose regimens of NER1006 (PLENVU^®, Norgine Ltd), a 1-liter polyethylene glycol (PEG) bowel preparation, to evaluate its bowel-cleansing efficacy in patients at risk for inadequate cleansing.

METHODS

Patients requiring colonoscopy were randomized to receive evening/morning split-dosing of either NER1006, 2-liter (2L) PEG and ascorbate, or oral sulfate solution (OSS). Bowel-cleansing efficacy was assessed by treatment-blinded central readers using the validated Harefield Cleansing Scale (HCS).

RESULTS

Split-dose NER1006 was associated with high levels of cleansing, ranging between 87.0% and 94.0% across all patient subtypes (n = 551), including patients with obesity or diabetes. However, patients aged >65 years and <45 years showed significantly greater rates of successful cleansing than patients aged 45-65 years (94.0% versus 94.2% versus 87.0%, p = 0.002). The high-risk patient subgroup, which included obese males aged ⩾60 years, had significantly improved overall and high-quality bowel-cleansing success rates of 100% (33/33) and 72.7% (27/33) on the HCS with NER1006, compared with 86.7% (26/30) and 50% (15/30) with the comparator solutions (p = 0.015 and p = 0.033, respectively). In this high-risk subgroup, adenoma detection was greater per patient receiving NER1006 versus the comparator group (1.82 versus 0.93, p = 0.041). NER1006 was the only treatment that enabled the detection of patients with ⩾5 adenomas [9.1% (3/33) versus 0/30, p = 0.047].

CONCLUSION

NER1006 effectively cleansed a broad range of patients and offered superior bowel cleansing versus 2LPEG/OSS in patients at increased risk of colorectal cancer. Future research should establish whether more effective cleansing also enables improved adenoma detection.

PLAIN LANGUAGE SUMMARY

A low-volume bowel preparation solution to better detect lesions associated with colorectal cancer during colonoscopyColorectal cancer (CRC) is the fourth most commonly diagnosed cancer in the world. Obese men over the age of 65 years are at particularly increased risk of developing CRC. If the changes in their large intestine (colon) could be seen more clearly during a colonoscopy (where a small camera is inserted via the anus to examine the bowels from the inside), patients who need treatment would be diagnosed earlier, thus improving their chances of survival. In this paper we discuss the use of a bowel preparation solution that is more convenient for patients (less to drink) but also cleans bowels more effectively, meaning more lesions are detected than when other solutions are used. This improved cleansing, and thus better visualization, occurred in a range of patients, including those at higher risk of CRC, such as older, overweight men.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

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.

A Multicenter Study of Colorectal Adenomas Rationale, Objectives, Methods and Characteristics of the Study Cohort

Background and Aims

The Multicenter Study of Colorectal Adenomas (SMAC) is a retrospective-prospective cohort study involving four Gastrointestinal Endoscopy Units in Italy. The main aim of the study is to evaluate the relationship between clinical and pathologic information at index colonoscopy and subsequent incidence of adenoma and colorectal carcinoma. We report the rationale, objectives and methods of the study, including patient characteristics at initial presentation.

Methods

All patients were consecutively identified from the endoscopy registries of the four Centres from January 1, 1985 to December 31, 1992. Inclusion criteria were: age 18-69 years, endoscopy performed with adequate toilette at least up to the rectosigmoid junction, and removal of all detectable polyps. Exclusion criteria were: familial adenomatous polyposis, inflammatory bowel diseases, adenocarcinoma in adenoma with infiltrated margins, previous invasive cancer at any site, colon resection and geographic inaccessibility.

Results

Out of 20,071 patients who underwent endoscopy at the four Centres, 11,959 fulfilled the eligibility criteria (5,892 males and 6,067 females, mean age = 51.1 ± 11.6 years). The main reasons for exclusion were age (n = 4,020) and previous or present colorectal cancer (n = 2,389). Symptoms were the most common reason for referral (72.3%), while post-polypectomy follow-up and positive fecal occult blood accounted for most of the remaining cases. A pancolonoscopy was performed in 3,088 patients (25.8%), while a left-sided endoscopy was performed in 7,887 (66%). A total number of 4,810 polyps were removed from 2,699 patients (2,994 adenomas, 1,580 hyperplastic polyps and 236 polyps lost after resection). A significant association (p < 0.001) between age and the endoscopic findings was observed. The subjects without polyps (n = 9,198) had the lowest age (mean = 49.9; 95%CL = 49.6 - 50.1) followed by the patients with hyperplastic polyps (n = 661; mean age = 52.3; 95%CL = 51.5-53.1), and the patients with adenomas (n = 1,732; mean age = 56.2; 95%CL = 55.8 - 56.6), and the patients with hyperplastic polyps and adenomas (n = 306; mean age = 57.2; 95%CL = 56.3 - 58.2). Polyps were diagnosed more frequently in males than in females (28.6% versus 17.0%; p < 0.0001).

Conclusion

This study provides some insights in the natural history of colorectal cancer and stresses the need to develop adequate strategies in the follow-up of subjects after either positive or negative colonoscopy.

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

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

Adiposity factors are not related to the presence of colorectal adenomas

Purpose

Adiposity has been thought to be related to colorectal carcinogenesis. The aim of this study was to explore any association between obesity factors and the presence of colorectal adenoma, a potential precancerous lesion.

Patients and methods

Two hundred and six consecutive patients undergoing colonoscopy without colorectal cancer were enrolled in the study. Anthropometric measures and other adiposity-related laboratory variables including insulin resistance and serum adiponectin levels were recorded and correlated with the presence of adenoma.

Results

Colorectal adenoma was detected in 68/206 patients (33%), tubular adenoma(s) in 38 patients, and tubulovillous or villous in 30 patients. Twenty-one patients (10.2%) had at least one proximal polyp. The size of the largest adenoma was ≤10 mm in 40 patients and >10 mm in 28 patients. No statistically significant difference was observed in body mass index, waist circumference, fasting plasma glucose concentration, insulin, homeostatic metabolic assessment, cholesterol, low-density lipoproteins, high-density lipoprotein, or triglycerides between patients with and without adenoma. In addition, there was no difference in plasma adiponectin between patients with adenoma (11.1 ± 6 μg/mL) and controls (10.2 ± 7.8 μg/mL). Furthermore, no significant difference in any parameter was found between patients with advanced adenoma and no advanced adenoma, nor between patients with proximal or distal tumors.

Conclusion

This study found that the presence of colorectal adenoma is not correlated with any adiposity factor. Moreover, obesity does not appear to be associated with the site or the presence of more advanced lesions.

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

OBJECTIVE

The findings from epidemiological studies addressing the association between adiposity and the risk of colorectal adenomatous polyps are inconsistent. We performed a meta-analysis of epidemiological studies including cross-sectional, case-control, and cohort studies.

METHODS

We searched PubMed and EMBASE in June, 2010. All searched articles were reviewed and selected independently by two evaluators according to pre-determined selection criteria.

RESULTS

We included 25 studies (nine cross-sectional studies, eleven case-control studies, and five prospective cohort studies) that comprised a total of 300,671 participants and 20,903 cases in the final analysis. When all studies were pooled, the odds ratio (OR) or relative risk (RR) of adiposity and abdominal adiposity for colorectal adenomatous polyp risk was 1.43 (95% confidence interval (CI) 1.23-1.67; n = 22) and 1.42 (95% CI 1.30-1.56; n = 12), respectively. Similarly, an increased risk of colorectal adenomatous polyps was observed in most of the subgroup meta-analyses.

CONCLUSIONS

Overall, we found that adiposity and abdominal adiposity significantly increased the risk of colorectal adenomatous polyps in a meta-analysis of epidemiological studies.

Excess body weight and obesity--the link with gastrointestinal and hepatobiliary cancer

Excess body weight (EBW) is an independent risk factor for many human malignancies, including cancers throughout the gastrointestinal and hepatobiliary tract from the esophagus to the colorectum. The relative risk of gastrointestinal cancer in obese individuals is approximately 1.5-2.0 times that for normal weight individuals, with organ-specific and gender-specific differences for specific cancers. The association between EBW and risk of premalignant stages of gastrointestinal carcinogenesis, such as colorectal adenoma and Barrett esophagus, is similar, implying a role for EBW during the early stages of carcinogenesis that could be relevant to preventative strategies. EBW also impacts negatively on gastrointestinal cancer outcomes. The mechanistic basis of the association between EBW and carcinogenesis remains incompletely understood. Postulated mechanisms include increased insulin and insulin-like growth factor signaling and chronic inflammation (both linked to the metabolic syndrome), as well as signaling via adipokines, such as leptin. The role of obesity-related changes in the intestinal microbiome in gastrointestinal carcinogenesis deserves further attention. Whether weight loss leads to reduced future gastrointestinal and liver cancer risk has yet to be fully explored. There is some support for the idea that weight loss negatively regulates colorectal carcinogenesis. In addition, data suggest a reduction in risk of several cancers in the first 10 years after bariatric surgery.

Visceral obesity and insulin resistance as risk factors for colorectal adenoma: a cross-sectional, case-control study

OBJECTIVES

Colorectal adenoma is known to be associated with obesity, but the association between colorectal adenoma and visceral adipose tissue (VAT) area measured by abdominal computed tomography (CT) has not been documented clearly. In addition, the relationship between insulin resistance and colorectal adenomas, which underlies the mechanism that links obesity and colorectal adenoma, has not been studied extensively. The aim of this study was to examine VAT area and insulin resistance as risk factors of colorectal adenoma.

METHODS

A cross-sectional, case-control study was conducted in Koreans that presented for health check-ups. Subjects underwent various laboratory tests, abdominal CT, and colonoscopy. VAT, subcutaneous adipose tissue (SAT), and homeostatic metabolic assessment (HOMA) index were evaluated as potential risk factors of colorectal adenoma in 2,244 age- and sex-matched subjects.

RESULTS

According to univariate analysis, the prevalences of smoking, hypertension, metabolic syndrome, and family history of colorectal cancer were higher in the adenoma group than in the normal control group. In addition, body mass index, waist circumference, triglyceride, high-density lipoprotein cholesterol, and VAT and SAT areas were significantly different in the two groups. According to the multivariate analysis adjusted for multiple confounders, VAT area was independently associated with the risk of colorectal adenoma (odds ratio (OR)=3.09, 95% confidence interval (CI): 2.19-4.36, highest quintile vs. lowest quintile). Mean HOMA index was higher in the adenoma group than in the control group (OR=1.99, 95% CI: 1.35-2.92, highest vs. lowest quintile).

CONCLUSIONS

Visceral obesity was found to be an independent risk factor of colorectal adenoma, and insulin resistance was associated with the presence of colorectal adenoma.

[Prevalence of colorectal adenoma is increased in patients with gastric adenoma]

BACKGROUND/AIMS

It has been reported that patients with gastric cancer may be at increased risk of synchronous or metachronous colorectal cancer. However, the incidence of colorectal adenoma in patients with gastric adenoma has not been discussed earlier. The aims of this study were to investigate the incidence of colorectal adenoma and to evaluate the necessity of colonoscopic surveillance in patients with gastric adenoma.

METHODS

We performed colonoscopy in 221 patients with gastric adenoma between January 2002 and June 2008. As a control group, 387 consecutive patients without gastric adenoma on gastroscopy who underwent colonoscopy were included. We retrospectively examined the endoscopic and colonoscopic findings as well as the clinicopathologic features.

RESULTS

Colorectal adenoma were diagnosed in 57.5% (127/221) of the gastric adenoma group and 38.0% (147/387) of the control group (p<0.001). Univariate analysis demonstrated that gender, age, past history of diabetes, and past history of gastric adenoma were associated with the risk of colorectal adenoma. Multivariate analysis demonstrated that gender (male, aOR 2.31, 95% CI 1.61-3.31), age (> or =50 years, aOR 2.47, 95% CI 1.53-4.01), past history of diabetes (aOR 2.35, 95% CI 1.32-4.20), and presence of gastric adenoma (aOR 1.63, 95% CI 1.13-2.36) appeared to be independent risk factors for colorectal adenoma.

CONCLUSIONS

The risk of colorectal adenoma increases significantly in patients with gastric adenoma. We suggest that colonoscopic surveillance may be necessary in patients with gastric adenoma.

Preoperative colonoscopy for patients with gastric adenocarcinoma

BACKGROUND AND AIM

In patients with gastric adenocarcinoma (GA), the most common double primary cancer is colorectal cancer. The aim of the present study was to evaluate the necessity of preoperative colonoscopy in patients with GA who have no symptoms of colorectal disease or any past/family history of colorectal cancer.

MATERIALS

Colonoscopy was carried out in 205 patients before gastric surgery for treatment of GA. The prevalence of colorectal neoplasms (CRN, adenoma and adenocarcinoma) was evaluated according to age, sex, body mass index (BMI) and stage, location and differentiation of GA.

RESULTS

The median age and BMI were 59 years (range 32-81) and 22.9 (range 17.0-42.3), respectively. There were 135 male patients (65.9%). Synchronous adenoma and adenocarcinoma were detected in 68 (33.2%) and four (2.0%) patients, respectively. Univariate analysis showed that patients 50 years and older, male or with multiple GA had a significantly higher incidence of CRN (P = 0.005, 0.019, and 0.023, respectively). All of the GA patients with synchronous colorectal adenocarcinoma were older than 50 years. The stage, location and differentiation of GA and BMI did not show a significant difference in the incidence of CRN. Multivariate analysis showed that age (50 years and older) was the only risk factor of CRN in GA patients (odds ratio 2.470; 95% confidence interval 1.058-5.767).

CONCLUSION

Preoperative colonoscopy for screening of CRN should be considered in GA patients > or = 50 years because of a relatively high prevalence of CRN and the possibility of synchronous CRC.

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.

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.

Factors that increase risk of colon polyps

Adenomatous polyps are common and factors that increase risk include race, gender, smoking, and obesity. This author summarizes the evidence supporting increased risk with these factors and describes how epidemiological data may be used to tailor screening programs.

The effect of body weight reduction on the incidence of colorectal adenoma

OBJECTIVES

Obesity is thought to be associated with colorectal cancer and adenoma. We aimed to investigate the effect of body weight on the risk of colorectal adenoma both in cross-sectional and longitudinal analyses.

METHODS

This is a retrospective cohort study in a large-scale health appraisal institution in Japan. A total of 7,963 asymptomatic, average-risk Japanese were enrolled at initial examinations, and 2,568 subjects who underwent a second colonoscopy after 1 yr were investigated. The association with the prevalence of colorectal adenoma was evaluated according to the body mass index (BMI) at the initial examination. The incidence of colorectal adenoma at the second colonoscopy was investigated according to the initial BMI and body weight changes during the year.

RESULTS

The prevalence of colorectal adenoma increased in relation to increases in the BMI: 15.4%, 20.6%, 22.7%, and 24.2%, respectively, in the first (BMI < 21.350), second (21.350 < or = BMI < 23.199), third (23.199 < or = BMI < 25.156), and fourth (25.156 < or = BMI) quartiles. The adjusted odds ratios in reference to Group Q1 were 1.15 (95% CI 0.97-1.37, P= 0.1) for Group Q2, 1.19 (1.01-1.41, P= 0.04) for Group Q3, and 1.32 (1.12-1.56, P= 0.001) for Group Q4. The incidence rates of colorectal adenoma after 1 yr also increased proportionally according to the initial BMI: Group Q1 (12.9%), Group Q2 (15.7%), Group Q3 (18.3%), and Group Q4 (19.0%).

CONCLUSIONS

Obesity was associated with the risk for colorectal adenoma, and body weight reduction was suggested to decrease this risk.

Anthropometric risk factors for colorectal polyps in African-American women

OBJECTIVE

Colorectal adenomas are thought to be precursor lesions to colorectal cancer, a leading cause of cancer incidence and mortality in African-American women. Studies suggest that obesity is associated with risk of adenomas in white women, but little is known about the relation in African-American women. We prospectively examined the association between selected anthropometric factors and colorectal polyps in African-American women.

METHODS AND PROCEDURES

Data were obtained from the Black Women's Health Study (BWHS), a prospective cohort study of African-American women. From 1997 to 2003, we followed 33,403 women aged > or =30 years with no prior diagnosis of cancer or polyps. Cox regression was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for risk of polyps, with adjustment for potential confounders.

RESULTS

After 211,797 person-years of follow-up, 1,189 cases of colorectal polyps were reported. The IRR comparing women with a current BMI > or =35 to <25 kg/m(2) was 1.35 (95% CI = 1.12-1.62), after adjustment for covariates including waist-to-hip ratio (WHR). Women who gained > or =30 kg since age 18 were 1.76 times as likely as those who gained <5 kg to report polyps (95% CI = 1.33-2.33). The IRR comparing the highest (>or =0.87) to lowest (<0.71) quintiles of WHR was 1.26 (95% CI = 1.04-1.54), after adjustment for covariates including BMI. BMI at age 18, adult height, and waist circumference (BMI-adjusted) were not materially associated with risk. Results were similar among women with a recent endoscopy.

DISCUSSION

Weight gain and obesity in adulthood may increase the risk of colorectal polyps in African-American women.

The anatomical distribution of colorectal cancer in Korea: evaluation of the incidence of proximal and distal lesions and synchronous adenomas

OBJECTIVE

The incidence of colorectal cancer throughout the Republic of Korea has been rising over the last 25 years. The change in incidence is supposed to be due to the westernized life style. We evaluated the anatomical distribution of colorectal cancer and the properties of synchronous adenomatous polyps in the Korean population which were known to be different from those in Western countries.

MATERIALS AND METHODS

From January 1997 to December 2006, 896 cases of colorectal cancer were reviewed retrospectively.

RESULTS

A total of 25.1% were proximally located cancer with a modest female predominance (odds ratio 1.5). Synchronous adenomatous lesions were accompanied in 31.9% of all colorectal cancer cases. In the distal colorectal cancer patients, 18.8% had proximally located synchronous adenomas. In those with proximal colon cancer, only 20.5% of patients had distally located adenomas. The likelihood of a proximal colon cancer without distal sentinel lesions was higher in females (odds ratio 3.0).

CONCLUSION

There has been a steep rise in the incidence of colorectal cancer in Korea and distal colon cancer is more prevalent than in Western countries. However, as over 20% of proximal colon cancers can exist without distal colonic synchronous or sentinel lesions, a total colonoscopic examination should be considered first in surveillance.

Association between body size and colorectal adenoma recurrence

BACKGROUND & AIMS

Obesity has been associated with increased risk for colorectal adenoma, although its role as a risk factor after polypectomy for recurrence is unclear. Therefore, we sought to evaluate the effect of anthropometric measures of obesity on adenoma after polypectomy.

METHODS

Subjects with baseline adenomas (n = 2465) and follow-up colonoscopy data were drawn from 2 randomized trials designed to prevent adenoma recurrence.

RESULTS

Over a mean follow-up period of 3.1 years presence of a body mass index (BMI) > or = 30 kg/m2 was associated with a nonsignificant 17% increase in the odds for any adenoma recurrence among all subjects (odds ratio [OR], 1.17; 95% confidence interval [CI], 0.92-1.48). This result was confined to men (OR, 1.36; 95% CI, 1.01-1.83) and not observed for women (OR, 0.90; 95% CI, 0.60-1.33). Results for waist circumference did not reach statistical significance, although trends were similar to those for BMI. Analyses of the effects of obesity on more clinically significant lesions demonstrated that high BMI was a slightly stronger risk factor for advanced adenoma recurrences in men (OR, 1.62; 95% CI, 1.04-2.53) when compared with non-advanced lesions (OR, 1.26; 95% CI, 0.91-1.75). In addition, we observed an association for obesity and odds of adenoma recurrence among participants reporting a family history of colorectal cancer (OR, 2.25; 95% CI, 1.32-3.84) but not for those without (OR, 1.00; 95% CI, 0.77 to 1.31; P(int) = P = .008).

CONCLUSIONS

Our results support obesity as a risk factor for subsequent short-interval (mean follow-up time 3.1 years) development of colorectal adenomas, particularly among men and persons with a family history of colorectal cancer. Furthermore, obesity in men appears to be strongly associated with the development of clinically advanced lesions.

An association between obesity and the prevalence of colonic adenoma according to age and gender

BACKGROUND

Epidemiologic data on obesity as a risk factor for colonic adenoma with respect to gender have not yet been confirmed. Here, we aimed to compare the prevalence of colonic adenoma and of advanced polyps in age-stratified men and women at baseline, to examine the role of body mass index (BMI) on colonic adenoma risk according to age and gender, and to examine the influence of menopausal status.

METHODS

A total of 1744 asymptomatic patients (946 men, 798 women) who underwent colonoscopy for cancer screening at Ewha Mokdong Hospital, Seoul, Korea, between February and June 2005, were eligible. BMI was assessed, and histology, size, and location of the adenoma were examined for each patient. Women were interviewed for menopausal status and a history of hormone replacement therapy.

RESULTS

A significant increase in the prevalence of colonic adenoma and of advanced polyps was found to occur with age (P for trend < 0.01). The prevalences of adenoma and advanced polyps were higher in men in most age groups (P < 0.01), but no significant difference in prevalences was observed between genderes in patients 70 years of age or older. Moreover, a positive association between BMI and the prevalence of colonic adenoma and advanced polyps was shown in relatively young individuals of both gender (men in their thirties, P < 0.05; women in their forties, P < 0.05), and premenopausal women according to hormonal status (P = 0.01).

CONCLUSIONS

Our data suggest that obesity increases the risk of colonic adenoma in relatively young people and in premenopausal women subject to estrogen effects.

Change in body size and the risk of colorectal adenomas

Adiposity has been recognized as a risk factor for colorectal adenoma, but the influence of weight gain, adipose tissue distribution, and possible differences between ethnic/racial and gender groups remains unanswered. The aim of this prospective study was to examine the association between adiposity and weight change and colorectal adenoma risk. Over approximately 10-year period, anthropometric measures and other risk factors were measured at three time points in the multicenter multiethnic Insulin Resistance Atherosclerosis Study cohort. Colonoscopies were then conducted on 600 cohort participants regardless of symptoms whose mean age at colonoscopy was 64 years. Multivariate logistic regression analyses were used to assess the association between colorectal adenomas and measures of adiposity and weight change over the approximately 10-year period before colonoscopy. Obesity was positively associated with risk of colorectal adenomas at the time of colonoscopy [adjusted odds ratio (OR(adj)), 2.16; 95% confidence interval (95% CI), 1.13-4.14] and was stronger in women (OR(adj), 4.42; 95% CI, 1.53-12.78) than in men (OR(adj), 1.26; 95% CI, 0.52-3.07). The risk of adenomas increased among participants who gained weight compared with those who maintained weight over the approximately 5 years (OR(adj), 2.30; 95% CI, 1.25-4.22) and approximately 10 years (OR(adj), 2.12; 95% CI, 1.25-3.62). These associations were similar for both advanced and nonadvanced adenomas. These results suggest a positive association between obesity, weight gain, and colorectal adenoma risk. Stronger associations were observed when obesity was measured at the time of colonoscopy, suggesting that obesity may be a promoting factor in the growth of colorectal adenomas.

Body mass index: a marker for significant colorectal neoplasia in a screening population

BACKGROUND AND AIMS

Although some studies suggest a positive association between increasing body mass index (BMI) and risk for colorectal neoplasia, the impact on screening has not been examined. We performed a cross-sectional study to examine the association of BMI and colorectal neoplasia in a screening population.

METHODS

Data collected for 2493 patients presenting for screening colonoscopy included known risk factors for colorectal neoplasia, demographic information, and lifestyle factors. Our outcome was the endoscopic detection of significant colorectal neoplasia which included adenocarcinoma, high-grade dysplasia, villous tissue, adenomas 1 cm or greater and multiple (>2) adenomas of any size.

RESULTS

Overall, we observed an increased risk and prevalence for significant colorectal neoplasia in women as BMI increased (P value for trend <0.002). This relationship was the strongest for the women with a BMI > or =40 (odds ratios=4.26; 95% confidence intervals=2.00-9.11). There was no such relationship in our male population.

CONCLUSIONS

Increasing BMI, in our population, was associated with an increase risk for colorectal neoplasia in female patients. This study reinforces the importance of screening colonoscopy especially in obese women.

The association of physical activity and body mass index with the risk of large bowel polyps

PURPOSE AND METHOD

Several studies have suggested that physical inactivity and obesity increase the risk for colorectal neoplasia. In this study, we investigated the association of physical activity and body mass index (BMI) with the risk of different types of large bowel polyps. We did an observational analysis nested within a randomized double-blind placebo-controlled chemoprevention trial among patients with one or more recently resected histologically confirmed colorectal adenoma. Nine hundred thirty patients were randomized to calcium (1,200 mg/d, as carbonate) or placebo. Follow-up colonoscopies were conducted approximately 1 and 4 years after the qualifying examination. At study entry, we obtained each subject's current body weight and height, which we used to calculate BMI. After the second study colonoscopy, we asked subjects questions about their leisure time physical activity. Seven hundred eighty-seven subjects completed at least part of the physical activity questionnaire.

RESULTS

We found no association between measures of physical activity or BMI and tubular adenomas or hyperplastic polyps. However, among men, there were strong inverse associations observed between physical activity and advanced neoplastic polyps. Compared with men whose total daily energy expenditure was in the lowest tertile, those in the highest tertile had a risk ratio of 0.35 (95% confidence interval, 17-0.72); there was no similar reduction observed among women (risk ratio, 1.21; 95% confidence interval, 0.36-4.03; P for interaction = 0.04).

DATA INTERPRETATIONS

We found a significant inverse relationship between several measures of physical activity and risk of advanced colorectal neoplasms, particularly among men. No associations were found between BMI and hyperplastic polyps, tubular adenomas, or advanced neoplastic polyps.

Use of colonoscopy as a primary screening test for colorectal cancer in average risk people

OBJECTIVE

The use of colonoscopy as a primary screening test for colorectal cancer (CRC) in average risk adults is a subject of controversy. Our primary objective was to build a predictive model based on a few simple variables that could be used as a guide for identifying average risk adults more suitable for examination with colonoscopy as a primary screening test.

METHODS

The prevalence of advanced adenomas was assessed by primary screening colonoscopy in 2210 consecutive adults at least 40 yr old, without known risk factors for CRC. Age, gender, and clinical and biochemical data were compared among people without adenomas, those with non-advanced adenomas, and those with any advanced neoplasm. A combined score to assess the risk of advanced adenomas was built with the variables selected by multiple logistic regression analysis.

RESULTS

Neoplastic lesions were found in 617 subjects (27.9%), including 259 with at least one neoplasm that was 10 mm or larger, villous, or with moderate-to-severe dysplasia, and 11 with invasive cancers. Advanced lesions were more frequent among men, older people, and those with a higher body mass index (BMI). These three variables were independent predictors of advanced adenomas in multivariate analysis. A score combining age, sex, and BMI was developed as a guide for identifying individuals more suitable for screening colonoscopy.

CONCLUSIONS

Age, gender, and BMI can be used to build a simple score to select those average risk adults who might be candidates for primary screening colonoscopy.

Energy intake, body mass index, physical activity, and the colorectal adenoma-carcinoma sequence

Little is known about the precise relationship between energy intake, overweight, sedentary lifestyle, and steps in the colorectal adenoma-carcinoma pathway. We studied these parameters within a case-control study. Patients with adenomas < 10 mm (n = 154) or > 10 mm (n = 208) were compared with polyp-free controls (n = 426) for determining factors associated with adenoma formation, i.e., observed for small and large adenomas, or with adenoma growth only. Colorectal cancer cases (n = 171) were compared with population controls (n = 309) to determine factors specific to the final stage, cancer. Exercise reduced the risk of cancer [odds ratio (OR) = 0.3, 95% confidence interval (CI) = 0.2-0.5 for high vs. low physical activity] but had little influence on adenomas. High energy intake increased the risk of cancer [OR for 5th vs. 1st quintile (OR5) = 1.6, 95% CI = 0.9-2.9, p = 0.02], but not of adenomas. High body mass index (BMI) significantly increased the risk of large adenomas (OR5 = 2.1, 95% CI = 1.2-3.5, p = 0.02 and OR5 = 1.7, 95% CI = 1.0-3.1, p = 0.25) for large and small adenomas vs. polyp-free controls. Neither height nor weight nor BMI influenced the risk of cancer. Results were unmodified when controlling for dietary risk factors and family history. Energy intake, a sedentary lifestyle, and high BMI were independently associated with a high risk of cancer itself or large adenomas, which indicates an effect on promotion of colorectal tumors. These findings suggest that preventive advice regarding these factors should be provided, even late in life, to decrease the risk of colorectal cancer.

Does high body fatness increase the risk of presence and growth of colorectal adenomas followed up in situ for 3 years?

OBJECTIVE

Obesity is an increasing problem for industrialized nations. The incidence of colorectal cancer has also risen during the last decades. However, information is scarce about the association between the colorectal cancer precursors, adenomatous polyps, and body composition. Our aim was to find out if body fatness is related to the presence of polyps and of growth of adenomas of < or =9 mm observed in situ over 3 yr.

METHODS

Twenty-eight outpatients with colorectal polyps and 50-75 yr of age were compared with 34 sex- and age-matched (+/-5 yr) polyp-free healthy controls. The polyp patients were randomly selected from a double blind 3-yr placebo-controlled endoscopic follow-up and intervention study against growth and recurrence of polyps among 116 polyp-bearing outpatients. Triceps skinfold thickness (TSF) was measured by a Harpenden caliper and total body fat percentage (BF%) by Futrex 5000. Dietary intake was calculated in a 5-day dietary record by weighing. Demograpic data, including smoking and alcohol habits, were registered by an interview and self-administrated questionnaires. Weight and height were measured.

RESULTS

TSF and BF% ranked 66% of the individuals into the same quartiles, and 34% were ranked into the adjacent quartiles. The coefficient of correlation between TSF and BF% was highly significant (r = 0.90, p < 0.01, n = 62). TSF, BF%, and body mass index (kg/m2) did not differ between polyp patients and controls in either crude or adjusted analyses. Adenoma growth was, however, highly associated with increasing levels of TSF (p = 0.004), BF% (p = 0.02), and body mass index (p = 0.006).

CONCLUSIONS

Our data suggest that high body fatness is a promoter of adenoma growth. Similar results were obtained with the caliper and Futrex 5000, which lends credibility to this study. For repeated documentation, a larger study population should be investigated. To our knowledge, this is the first case-control study to investigate the relationship between body composition and growth of adenoma by follow-up in situ over 3 yr.

Circulating insulin-like growth factor II and colorectal adenomas

Circulating insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) may be risk factors for the development of colorectal cancer. On the other hand, IGF-II and IGFBP-2 are overexpressed in colorectal carcinomas. These contrasting backgrounds led us to investigate the relationship between serum IGF-I, IGF-II, IGFBP-2, and IGFBP-3 and the presence of colorectal adenomas, known precursors of colorectal carcinoma, in 345 volunteers attending a screening flexible sigmoidoscopy trial (entry criteria: healthy, aged 55-64 yr). The most striking finding was an elevated mean serum IGF-II in individuals with adenomas (n = 52) compared with controls (mean difference, 139 ng/mL; 95% confidence intervals, 82, 196; P < 0.0001). Logistic regression adjusting for confounding factors confirmed the significant association between IGF-II and adenoma occurrence (P < 0.0001) and revealed an additional positive association with serum IGFBP-2 (P < 0.0001). However, there was no association found between either serum IGF-I and/or IGFBP-3 and the presence of adenomas. Additionally, in 31 individuals with adenomas in whom levels were determined pre- and postpolypectomy, there was a significant fall in mean IGF-II (P < 0.001) and IGFBP-2 (P < 0.001) after adenoma removal, but no difference in IGF-II and IGFBP-2 concentrations between repeated samples in 20 individuals without adenomas. Immunohistochemical studies demonstrated IGF-II expression in 83% of all adenomas, which contrasted with absent expression in normal colonic expression and hyperplastic polyps. This study has shown for the first time that serum IGF-II may be a tumor marker in individuals with colorectal adenomas. Further studies are needed to validate these relationships in larger populations, including individuals undergoing colonoscopy.

Physical activity, obesity, and risk of colorectal adenoma in women (United States)

The relationship between physical inactivity, body mass index (BMI) (wt[kg]/ht[m]2), and pattern of adipose distribution with risk of colorectal adenomas (precursors of cancer) was examined in 13,057 female nurses in the United States, 40 to 65 years of age in 1986, who had an endoscopy between 1986 and 1992. From 1986 to 1992, 439 participants were newly diagnosed with adenomas of the distal colorectum. After controlling for age, prior endoscopy, parental history of colorectal cancer, smoking, aspirin, and intakes of animal fat, dietary fiber, folate, methionine, and alcohol, physical activity was associated inversely with risk of large (> or = 1 cm) adenomas in the distal colon (relative risk [RR] = 0.57, 95 percent confidence interval [CI] = 0.30-1.08, comparing high and low quintiles of average weekly energy expenditure from leisure-time activities; P trend = 0.05). Much of the benefit came from activities of moderate intensity such as brisk walking. In addition, BMI was associated directly with risk of large adenomas in the distal colon (multivariate RR = 2.21 [CI = 1.18-4.16], P trend = 0.0001, for BMI > or = 29 cf < 21 kg/m2). Waist circumference and the waist-to-hip ratio (WHR) were not related significantly to adenoma independently of BMI, but women with both a high BMI and high WHR were at greater risk of large colon adenoma (multivariate RR = 1.99, CI = 0.98-4.05) than women with high BMI but relatively low WHR (multivariate RR = 1.35, CI = 0.61-2.97). BMI was not related to small (< 1 cm) adenoma risk but physical activity had an inverse association with small adenomas in the distal colon (multivariate RR = 0.68, CI = 0.40-1.15, P trend = 0.03). The relationships between BMI or physical activity were considerably weaker and inconsistent for rectal adenomas. These results, in women, support an inverse association between physical activity and occurrence or progression of adenomas in the distal colon; obesity is associated with an elevated risk of large adenomas.

Insulin and colon cancer

Some factors related to Westernization or industrialization increase risk of colon cancer. It is believed widely that this increase in risk is related to the direct effects of dietary fat and fiber in the colonic lumen. However, the fat and fiber hypotheses, at least as originally formulated, do not explain adequately many emerging findings from recent epidemiologic studies. An alternative hypothesis, that hyperinsulinemia promotes colon carcinogenesis, is presented here. Insulin is an important growth factor of colonic epithelial cells and is a mitogen of tumor cell growth in vitro. Epidemiologic evidence supporting the insulin/colon-cancer hypothesis is largely indirect and based on the similarity of factors which produce elevated insulin levels with those related to colon cancer risk. Specifically, obesity--particularly central obesity, physical inactivity, and possibly a low dietary polyunsaturated fat to saturated fat ratio--are major determinants of insulin resistance and hyperinsulinemia, and appear related to colon cancer risk. Moreover, a diet high in refined carbohydrates and low in water-soluble fiber, which is associated with an increased risk of colon cancer, causes rapid intestinal absorption of glucose into the blood leading to postprandial hyperinsulinemia. The combination of insulin resistance and high glycemic load produces particularly high insulin levels. Thus, hyperinsulinemia may explain why obesity, physical inactivity, and a diet low in fruits and vegetables and high in red meat and extensively processed foods, all common in the West, increase colon cancer risk.

Diseases preceding colon cancer. A case-control study among veterans

Patients with regular use of nonsteroidal antiinflammatory drugs (NSAIDs) appear to have a reduced mortality from colon cancer. As NSAID use is associated with gastrointestinal bleeding, endoscopic exploration of patients on NSAID may lead to more efficient screening and frequent detection of colon cancer. A case-control study was conducted among 12,304 veterans with a colon cancer diagnosed between 1988 and 1992. Four controls were matched by age, sex, and race to each case. The frequency distributions of previous discharge diagnoses in cases and controls were compared. Arterial embolism and thrombosis, spondylosis, peripheral vascular disease, angina, osteoarthrosis, and ischemic heart disease protected against future development of colon cancer. On the other hand, atrial fibrillation and flutter, as well as phlebitis and thrombophlebitis, were associated an increased occurrence of colon cancer after 5-10 years. The study contrasts diseases that are treated with aspirin with those that are treated with other anticoagulants. Both cause bleeding, but the reduced risk of colon cancer was seen only in conditions treated with aspirin. The difference between the two disease groups from the same VA patient population suggests that chronic use of NSAID truly protects against future development of colon cancer.

Diet and adenomatous polyp risk

Studies of risk factors for colonic adenomatous polyps have been reported in greater numbers in 1993 than in all previous years combined. This explosion in interest in polyps has not arisen because polyps themselves cause serious illness. They are in the vast majority of cases asymptomatic. However, adenomas have become the surrogate for colon cancer in a number of phase III dietary intervention trials. These trials were undertaken at a time when very little was known of adenoma risk factors. Data accumulated in the past 18 months in general demonstrate a similarity in risk factors for cancer and polyp. Since it has also been recently established that polypectomy diminishes colon cancer risk, the adenomatous polyp has been established as an ethical and convenient surrogate for cancer of the colon. Prevention of colorectal cancer is the goal of all the above studies, and it is hoped that the dietary intervention trials currently under way will generate the data that will make prevention possible.

Obesity and adenomatous polyps of the sigmoid colon

The relation between obesity and adenomatous polyps of the sigmoid colon was investigated in male self-defense officials who received a retirement health examination at three hospitals of the Self-Defense Forces in Japan between January 1991 and December 1992. Body mass index (BMI) and waist-hip circumference ratio (WHR) were used as indices of obesity. A total of 228 adenoma cases and 1484 controls with normal sigmoidoscopy were identified in 2228 men: cases having small adenomas (< 5 mm in diameter) and those with large adenomas (5 mm or greater) numbered 115 and 102, respectively. Smoking, alcohol use, physical activity, rank, and hospital were controlled for by multiple logistic regression analysis. BMI and WHR were classified into four levels using the 30th, 60th, and 90th percentiles of each distribution in the control as cut-off points. There was a significant two-fold elevation in the overall adenoma risk among men at the highest BMI level (> or = 26.95) compared with those at the lowest level (< 22.48), but the risk did not linearly increase: a similar increase was also noted for large adenomas. While WHR was only weakly related to the overall adenoma risk, the risk of large adenomas progressively increased with increasing levels of WHR; odds ratio (OR) 2.9 (95% confidence interval (CI) 1.4-5.9) for the highest (> or = 0.958) versus lowest (< 0.878) levels. BMI was not materially associated with adenoma risk after additional adjustment for WHR, but a positive association between WHR and large adenomas was independent of BMI: OR 3.4 (95% CI 1.5-7.6) for the highest versus lowest levels. These findings suggest that obesity is associated with an increased risk of colon adenomas, probably with adenoma growth.

Gastrointestinal disturbances with obesity

Steatosis and steatohepatitis are associated with obesity. Despite florid histological changes, patients with non-alcoholic steatohepatitis generally remain asymptomatic, and it usually runs a relatively benign course. An elevated insulin level may be important in the pathogenesis. There is a marked regression of fatty changes after weight reduction. In obese subjects the risk of developing gallstones is increased due to an increased saturation of gallbladder bile with cholesterol and possible gallbladder stasis. During weight reduction with very low calorie diets the incidence in gallstones increases probably because of an increased saturation of bile during the loss of weight. Ursodeoxycholic acid appears to be a promising prophylactic agent. Chenodeoxycholic acid is not useful for these subjects. There is controversy over whether obesity contributes to gastroesophageal reflux and gastric emptying disturbances. There are changes in gastrointestinal peptide plasma levels in obesity but it is not clear if this contributes to its development. The risk for high-risk colorectal adenomas and carcinomas is reported to be increased in obese males. Vertical banded gastroplasty and gastric bypass procedures are nowadays the surgical options for the treatment of obesity. Nutritional deficiencies, particularly of vitamin B12, folate and iron are common after gastric bypass and must be sought and treated. Dumping is another potential complication of this operation. If stenosis and gastric outlet obstruction develop endoscopic dilatation is a good therapeutic option.