Risk Factor For Colorectal Adenoma Research Articles

Prevalence and risk factors for colorectal adenomas in patients with ulcerative colitis.

Patients with ulcerative colitis (UC) have an increased risk of colorectal cancer. Scarce data regarding the development of adenomas in these patients are available both for normal and colitic mucosa. The objective of this article is to evaluate the prevalence of adenomatous polyps and associated risk factors in patients with UC. Patients with UC were identified from the databases of two tertiary referral centers. Medical, endoscopic and histologic reports were reviewed. A total of 403 patients were included (53% male; 33% extensive colitis) and 1065 colonoscopies (median per patient, 2) were recorded and analyzed. Seventy-four adenomas in 47 patients (11.7%) and three cases of colorectal cancer were found during a median follow-up of 6.3 years. The cumulative risk of colorectal adenoma was 4.7%, 16.7%, 23.6% and 34.4% at 10, 20, 30 and 40 years from UC diagnosis, respectively. The cumulative risk of developing metachronous colorectal adenoma was 66.7%, 87.9%, and 90.9% at 5, 10, and 15 years from first adenoma detection. Older age at UC diagnosis and longer disease duration were independent risk factors for colorectal adenoma development. The prevalence of colorectal adenomas among UC patients seems to be higher than previously reported, although lower than in the background population.

Helicobacter Pylori Infection Increases the Risk of Colorectal Adenomas: an Updated Meta-Analysis.

H. pylori infection has been reported as a risk factor for colorectal adenoma (CRA); however, the clinical results were controversial. Therefore, we performed a meta-analysis to evaluate the association of H. pylori infection and CRA risk. A comprehensive literature search for relevant studies published up to November 2017 was performed using Medline and Embase, and the statistical analysis was conducted using Stata software. A total of twenty-five studies including 8,675 cases and 15,275 controls were included in the analysis. The pooled analysis showed that H. pylori infection was associated with an increased risk of CRA (OR = 1.86, 95% CI = 1.55 - 2.23). Subgroup analyses according to the ethnicity, study type, and H. pylori detection method were further conducted. The results showed that H. pylori infection was associated with an increased risk of CRA both in Caucasian (OR = 2.23, 95% CI = 1.36 - 3.66) and Asian population (OR = 1.58, 95% CI = 1.36 - 1.82). Both the case-control studies and cross sectional studies suggested the H. pylori infection could promote the risk of CRA (case control: OR was 2.00, 95% CI = 1.22 - 3.28; cross-sectional: OR was 1.68, 95% CI = 1.43 - 1.99). For H. pylori infection detection methods, there is significant association between H. pylori infection and CRA risk using the serum IgG method and RUT, but not with the UBT and IHC method. This analysis suggests that H. pylori infection may be a risk factor for CRA.

Anatomical distribution and detection rate of colorectal neoplasms according to age in the colonoscopic screening of a Korean population.

PurposeBecause data as a basis for the determination of proper age and modality for screening of colorectal neoplasms is lacking, we evaluated detection rates and anatomical distribution of colorectal neoplasms according to age in healthy individuals who underwent total colonoscopy for health checkup.MethodsA total of 16,100 cases that had received the colonoscopic examination from January to December in 2014 were analyzed. The total number of individuals who received total colonoscopy were divided by the number of individuals harboring colorectal adenoma to calculate the detection rate of colorectal adenoma. Individuals ≤50 years old were classified as young-age group and aged >50 were old-age group. Differences in anatomical locations of colorectal neoplasms were analyzed in the 2 age groups by chi-square test. Risk factors for colorectal adenoma in each age group were analyzed using univariate and multivariate logistic regression analyses.ResultsDetection rates of colorectal adenoma were 13.7% in all cases and 12.8% for those in their 40′s. The main anatomical location of colorectal adenoma was proximal colon in both age groups (P < 0.001). Hyperplastic polyp was mainly distributed to the distal colon in both age groups (P < 0.001). Distal colon was the major site for colorectal cancer in the old-age group (P = 0.001). Proximal location of neoplasms was a risk factor for colorectal adenoma in both age groups with multivariate analysis.ConclusionThese data could be the bases for earlier initiation of screening for colorectal neoplasms with total colonoscopy to detect clinically significant colorectal polyps.

Frequency and risk factors of colorectal adenoma in patients with early gastric cancer.

The authors aimed to determine the clinical value of colonoscopy by evaluating the frequency of colorectal neoplasm (CRN) detection in patients with early gastric cancer (EGC) as compared with healthy controls and analysed the risk factors of advanced CRN in patients with EGC. The medical records of 201 patients diagnosed as EGC and age- and gender-matched healthy controls were retrospectively reviewed. Frequencies and clinical features of colorectal polyps of patients and controls were compared. Risk factors of advanced CRN in patients with EGC were also analysed. Frequencies of CRN in patients and controls were 49.8 and 49.3% respectively (P = 0.90). They were more common in the right colon in patients (P < 0.05). Advanced CRN were found in 10.3% of patients and in 3% of controls (P < 0.05). Multivariate analysis revealed that old age and smoking history were risk factors of an advanced CRN in patients with EGC. The prevalence of a coexisting advanced CRN was higher in EGC patients. The study shows colonoscopy plays an important role with respect to the detection of synchronous advanced CRN in patients with EGC.

Su1666 Bmi Is Not a Significant Risk Factor for Colorectal Adenomas in a Predominantly African American, Female Inner-City Population

Su1666 Bmi Is Not a Significant Risk Factor for Colorectal Adenomas in a Predominantly African American, Female Inner-City Population

Meat and fish consumption and risk of colorectal adenomas in Korea.

559 Background: Consumption of red meat and alcohol are known risk factors for colorectal cancer. Colorectal adenomas are considered precursors to colorectal cancer through adenoma-carcinoma sequence. The identification of modifiable risk factors for colorectal adenoma contributes to prevent colorectal cancer from progressing. Many studies have suggested that high red meat or processed meat intake is associated with an increased risk of colorectal adenoma. However, the effect of high fish intake on colorectal adenoma has been insufficient in epidemiological studies. The aim of this study is examine the relationship between meat and fish intake and the risk of colorectal adenoma. Methods: The study enrolled participants who visited Seoul National University Hospital Healthcare System Gangnam Center from May to December, 2011. All participants underwent screening colonoscopy and completed validated food frequency questionnaire. The study sample included 414 adenoma patients, 142 advanced adenoma patients and 1160 polyp-free controls. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between meat and fish and colorectal adenoma using multivariate logistic regression. Results: The intake of total meat, red meat, poultry or processed meat showed no clear association with risk of colorectal adenoma or advanced adenoma. A significant negative association between fish intake and risk of advanced adenoma (OR = 0.51, 95% CI = 0.27 – 0.95, p for trend = 0.0281) after adjusting for confounders such as age, BMI, family history of colorectal cancer, alcohol consumption, smoking status, diabetes, total energy intake, fiber, vegetable/fruit and red meat intake. Conclusions: In conclusion, this study showed no clear relationship between the incidence of colorectal adenoma/advanced adenoma and meat intake. Although, high fish intake and incidence of advanced adenoma showed a significant inverse association in Korean.

Helicobacter pylori infection with intestinal metaplasia: An independent risk factor for colorectal adenomas.

AIMTo explore the association between Helicobacter pylori (H. pylori) infection status, intestinal metaplasia (IM), and colorectal adenomas.METHODSWe retrospectively reviewed 1641 individuals aged ≥ 40 years who underwent physical examination, laboratory testing, 13C-urea breath testing, gastroscopy, colonoscopy, and an interview to ascertain baseline characteristics and general state of health. Histopathological results were obtained by gastric and colorectal biopsies.RESULTSThe prevalence of H. pylori infection and adenomas was 51.5% (845/1641) and 18.1% (297/1641), respectively. H. pylori infection was significantly correlated with an increased risk of colorectal adenomas (crude OR = 1.535, 95%CI: 1.044-1.753, P = 0.022; adjusted OR = 1.359, 95%CI: 1.035-1.785, P = 0.028). Individuals with IM had an elevated risk of colorectal adenomas (crude OR = 1.664, 95%CI: 1.216-2.277, P = 0.001; adjusted OR = 1.381, 95%CI: 0.998-1.929, P = 0.059). Stratification based on H. pylori infection stage and IM revealed that IM accompanied by H. pylori infection was significantly associated with an increased risk of adenomas (crude OR = 2.109, 95%CI: 1.383-3.216, P = 0.001; adjusted OR = 1.765, 95%CI: 1.130-2.757, P = 0.012).CONCLUSIONH. pylori-related IM is associated with a high risk of colorectal adenomas in Chinese individuals.

Type 2 diabetes mellitus and risk of colorectal adenoma: a meta-analysis of observational studies

BackgroundTo summarize the relationship between type 2 diabetes mellitus (T2DM) and risk of colorectal adenomas (CRA), we performed a meta-analysis of observational studies.MethodsTo find studies, we searched PubMed, Embase, the Cochrane Library, Web of Science and conference abstracts and related publications for American Society of Clinical Oncology and the European Society of Medical Oncology. Studies that reported relative risks (RRs) or odds ratios (ORs) with 95 % confidence intervals (CIs) for the association between T2DM and risk of CRA were included. The meta-analysis assessed the relationships between T2DM and risk of CRA. Sensitivity analyses were performed in two ways: (1) by omitting each study iteratively and (2) by keeping high-quality studies only. Publication bias was detected by Egger’s and Begg’s tests and corrected using the trim and fill method.ResultsThis meta-analysis included 17 studies with 28,999 participants and 6798 CRA cases. We found that T2DM was a risk factor for CRA (RR: 1.52; 95 % CI: 1.29–1.80), and also for the advanced adenoma (RR: 1.41; 95 % CI: 1.06–1.87). Patients with existing T2DM (RR: 1.56; 95 % CI: 1.16–2.08) or newly diagnosed T2DM (RR: 1.51; 95 % CI: 1.16–1.97) have a risk of CRA. Similar significant results were found in retrospective studies (RR: 1.57; 95 % CI: 1.30–1.89) and population based cross-sectional studies (RR: 1.46; 95 % CI: 1.21–1.89), but not in prospective studies (RR: 1.27; 95 % CI: 0.77–2.10).ConclusionsOur results suggested that T2DM plays a risk role in the risk of developing CRA. Consequently, medical workers should increase the rate of CRA screening for T2DM patients so that they can benefit from behavioural interventions that can help prevent the development of colorectal cancer. Additional, large prospective cohort studies are needed to make a more convincing case for these associations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2685-3) contains supplementary material, which is available to authorized users.

Weight Change and Obesity Are Associated with a Risk of Adenoma Recurrence.

Obesity is reportedly a risk factor for colorectal adenoma. However, the influence of weight change and obesity on colorectal adenoma recurrence is unclear. To investigate whether weight change and obesity are associated with recurrence and development of colorectal adenoma. Of 62,171 asymptomatic subjects who underwent a colonoscopy for a heath checkup between 2010 and 2011, this longitudinal study was performed with the 5297 subjects who underwent another colonoscopy between 2012 and 2013. The risk of recurrence or development of adenoma according to quartiles of weight change (<-1.6, -1.6 to 0.1, 0.2-1.8, and ≥1.9kg) and baseline BMI categories (<25, 25-29, and ≥30kg/m(2)) was assessed using Cox proportional hazards modeling. The average period between visits 1 and 2 was 2.2±0.6years. Among the 2176 subjects with adenomas, the risk of recurrence of any adenoma increased with increasing weight change quartiles (p for trend=0.030), whereas the risk of recurrence of advanced adenoma was not associated with weight change (p for trend=0.852). The risk of recurrence of advanced adenoma increased with increasing baseline BMI categories (p for trend=0.029). Among 3121 subjects with no adenoma, the risk of developing any adenoma increased with increasing baseline BMI categories (p for trend <0.001). However, the risk of developing any or advanced adenoma was not associated with weight change. Weight change over 2.2years affected adenoma recurrence and obesity was related to advanced adenoma recurrence and adenoma development.

Prevalence of colorectal adenomas in asymptomatic young adults: a window to early intervention?

ABSTRACTObjective The prevalence of colorectal adenoma is increasing in the average-risk population. However, little research is available on colorectal adenoma in young adults under age 40. The aim of this study was to investigate the prevalence and risk factors of colorectal adenoma in 20- to 39-year-old adults. Methods We evaluated 4286 asymptomatic young adults aged 20 to 39 years who underwent first colonoscopy screening as part of an employer-provided health wellness programme at the Health Promotion Centre of Samsung Changwon Hospital, Korea from January 2011 to December 2013. Logistic regression modelling was used to identify risk factors for colorectal adenoma in asymptomatic young adults. Results The prevalence of colorectal adenoma and advanced adenoma was 11.6% (497/4286) and 0.9% (39/4286), respectively. By age group, the prevalence of colorectal adenoma was 5.4% (33/608) in participants aged 20 to 29 years and 12.6% (464/3678) in participants aged 30 to 39. Colorectal adenoma was found in 13.1% (403/3072) of men and 7.7% (94/1214) of women. Increased risk of colorectal adenoma was associated with age over 30 years (OR, 2.37; 95% CI, 1.64–3.42), current smoker status (OR, 1.48; 95% CI, 1.14–1.91), and alcohol consumption (OR, 1.29; 95% CI, 1.03–1.63). Conclusions Our findings indicate that even if the prevalence of colorectal adenoma was low in young adults aged 20 to 39, being over 30, cigarette smoking, and alcohol consumption can affect young adults who have no other CRC risks.

High levels of carcinoembryonic antigen and smoking might be markers of colorectal adenoma in Korean males aged 40-49 years

Background: Prevalence of adenoma in males aged 40-49 years in Korea was higher than expected. The aim of this study was to investigate the prevalence and risk factors of colorectal adenoma in males aged 40-49 years. Methods: Total 1,902 asymptomatic subjects with a mean age of 47.9±6.7 years, who underwent a screening colonoscopy in a health promotion center of Myongji Hospital from 2010 to 2013 were enrolled in this study. We conducted a case-control study to determine the risk factors for adenoma. The subjects were classified into two groups (adenoma vs. controls). To validate the diagnostic value of carcinoembryonic antigen (CEA) for adenoma, area under the receiver operating characteristic curve (AUROC) was calculated. Results: At least one colorectal adenoma was identified in 385 subjects (20.2%). Among these 385 subjects, 372 subjects were found to have a non-advanced adenoma, 13 subjects had an invasive adenoma. One subject had cancer. Male sex, age, smoking, metabolic syndrome, and elevated CEA level were significantly associated with a colorectal adenoma in univariate analysis. However, metabolic syndrome was not significant in multivariate analysis. In the male group, the AUROC of CEA for colorectal adenoma was 0.600 (0.543 to 0.656) in non-smokers under 50 years of age, and 0.615 (0.540 to 0.690) in smokers under 50 years of age. Conclusion: Male sex, smoking, and high levels of CEA seem to be associated with colorectal adenoma. High levels of CEA and smoking may be diagnostic markers for any colorectal adenoma in Korean males aged 40-49 years.

Visceral adipose tissue and the risk of colorectal adenomas: a meta-analysis of observational studies.

Visceral adipose tissue (VAT)-related metabolic syndromes are hypothesized to promote colorectal neoplasia; however, the results from studies investigating whether VAT directly measured by computed tomography is a risk factor for colorectal adenomas (CRA) have been inconsistent. We carried out a meta-analysis of epidemiological studies to quantitatively assess this association and dose-response relationship between VAT and the risk of CRA. We searched PubMed for relevant studies that were published in any language, from January, 1950 to June, 2010. Three case-control studies and eight cross-sectional studies involving 11 111 participants contributed toward this meta-analysis. We pooled the odds ratio (OR) from individual studies and carried out dose-response, heterogeneity, and publication bias analyses. In a pooled analysis of all studies, the amount of VAT (in a comparison of the highest and lowest categories) was associated with an increased risk of CRA (OR=1.67, 95% confidence interval: 1.29-2.16). Subgroup meta-analyses by both sexes, VAT measurements, study designs, and Asian ethnicity yielded similar results. An increase of 500 cm of VAT volume was related to an increased risk of CRA from the dose-response meta-analysis (OR=1.06; 95% confidence interval: 1.03-1.11). These results suggest that a large amount of VAT measured by computed tomography significantly increases the risk of CRA both in men and in women.

Analysis of population screening results for colorectal cancer and the risk factors of colorectal adenoma in prediabetes in Hefei communities

Objective To explore the prevalence of colorectal cancer and the risk factors associated with colorectal adenoma in prediabetes in community population. Methods Preliminary screening for colorectal cancers was carried out to prediabetes subjects aged over 40 years in four communities in Hefei City, by combining questionnaire and fecal occult blood test. Colonscopy were performed among high risk people, and the clinical characteristics of colorectal adenoma and related risk factors were also analyzed. Results A total of 1 912 people were investigated, and 547 cases of them were referred to high-risk group. Colonscopy were performed to 501 cases, and colorectal mucosa lesions were found in 281 cases, the detection rate was 56.1%(281/501). Of which colorectal cancer were found in 21 cases, the detection rate was 4.19%(21/501), nearly two-thirds belong to intermediate to late stages. In addition, colorectal adenomas were found in 248 cases, the detection rate was 49.5%(248/501), including multiple adenoma(43.1%), adenomatous polyps(58.1%), and 57.3% with the size of adenoma over 1 cm. The multiple logistic regression analyses revealed that male sex, waist-to-hip ratio, 2 h plasma glucose levels, and family history of diabetes were independent factors associated with increase in the risk of colorectal adenoma(P<0.05). Conclusion Early colorectal cancer screening and appropriate intervention measures should be taken in prediabetes. (Chin J Endocrinol Metab, 2015, 31: 851-855) Key words: Prediabetes; Colorectal cancer; Colonscopy; Risk factors

Abstract A46: Body mass index, waist circumference, and the risk of colorectal adenomas: Black Women's Health Study

Abstract Introduction: Overweight and obesity are independent risk factors for colorectal cancer among men and women. Associations of body mass index (BMI) with colorectal cancer risk are stronger among men than women. Evidence on the association of anthropometric factors with colorectal adenoma is more equivocal, especially among women. It has been suggested that the association of BMI with adenomas is weaker among postmenopausal women as compared to premenopausal women but data on this finding is limited. A recent study among participants in the PLCO trial failed to show an association of BMI with either colorectal adenoma or colorectal cancer risk among men and women. However, it is possible that BMI might not be the most relevant marker of obesity-associated colorectal neoplasia risk among women. A large cohort study of European Caucasian women showed a higher risk of colorectal cancer with waist circumference but not BMI. There are relatively few studies that have investigated multiple measures of obesity as risk factors for colorectal adenoma and cancer among women and none have been adequately powered for these analyses among African American women. We investigated the association of BMI and waist circumference as risk factors for colorectal adenoma among postmenopausal African American women in the Black Women's Health Study. Methods: We conducted a nested case-control study among participants in the Black Women's Health Study - a cohort study of 59,000 women followed biennially since 1995. Cases were defined as women diagnosed with incident colorectal adenoma between 1997 and 2011. Only those adenoma cases verified by medical record review were included. Controls were participants who also underwent lower gastrointestinal endoscopy and in whom no adenoma or other polyp was found. 3 controls were matched to each case based on age and follow-up period. Weight, height, and abdominal circumference were self-reported by participants at baseline. Weight and waist circumference were updated based on self-report every two years. BMI was categorized into 3 categories: 18-24.9 kg/m2 (normal BMI), 25-29.9 kg/ m2 (overweight), and ≥30 kg/ m2 (obese). Waist circumference was categorized in quintiles based on the distribution among controls. Using logistic regression models, we obtained odds ratios (OR) for colorectal adenoma in relation to BMI and waist circumference, adjusting for age, education, physical activity, fruit and vegetable intake, family history of colorectal cancer, smoking, alcohol intake, energy intake, aspirin use, menopausal status, and post-menopausal hormone therapy. Results: There were 915 adenoma cases and 2,745 controls. After adjusting for multiple covariates, neither overweight (OR: 1.10, 95% CI: 0.88-1.38) nor obese (OR: 1.09, 95% CI: 0.85-1.41) African-American women were at increased risk of colorectal adenomas than women with normal BMI. Although women in the fifth quintile of waist circumference were at higher risk of colorectal adenomas than those in the first quintile in age-adjusted models, the OR was no longer significant after multivariate adjustment (OR: 1.25, 95% CI: 0.94, 1.67) . Conclusions: We did not find an association of either BMI or waist circumference with colorectal adenomas among African-American women. Our results support the findings from other studies in primarily White women that showed no association of BMI with colorectal adenoma in women. Although the association of waist circumference with adenoma risk was stronger compared to BMI among African-American women in our study, it was not statistically significant. Further research is needed to confirm these findings, and explore the association of BMI and waist circumference with colorectal adenoma in African-American men. Citation Format: Chiranjeev Dash, Julie R. Palmer, Lynn Rosenberg, Jeffrey Yu, Lucile L. Adams-Campbell. Body mass index, waist circumference, and the risk of colorectal adenomas: Black Women's Health Study. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr A46.

A prospective evaluation of C-peptide levels and colorectal adenoma incidence

BackgroundObesity is a recognised positive risk factor for colorectal adenoma and colorectal cancer. Obesity is associated with insulin resistance and compensatory hyperinsulinaemia, and circulating insulin and C-peptide, a biomarker of insulin levels, have been positively associated with colorectal cancer risk. However, whether a similar relationship exists for colorectal adenomas, an established colorectal cancer precursor, is unclear. MethodsIn a nested case-control study of 273 colorectal adenoma cases and 355 matched controls from the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, serum C-peptide levels were measured by a chemiluminescent immunometric assay. Multivariable unconditional logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CI) for colorectal adenoma within quartiles of C-peptide. Further, to explore the temporal stability of C-peptide, repeat samples from the incident adenoma cases (n=50) and controls (n=30), over a 5-year period were assayed and the intra-class correlations (ICC) estimated. ResultsIn a multivariable model that included established colorectal adenoma risk factors, C-peptide levels were not associated with colorectal adenoma (Q4 vs. Q1, OR 0.83, 95% CI: 0.52–1.31; P-trend 0.32); similar null associations were observed by gender, by adenoma subsite and for advanced adenomas. Among control participants, the ICC value over a 5-year period was 0.66. ConclusionOur results suggest that higher C-peptide levels were not associated with colorectal adenoma incidence in this study population. Other biological pathways associated with obesity may be more relevant to the early stages of colorectal tumorigenesis.

Uric Acid Is a Risk Indicator for Metabolic Syndrome-related Colorectal Adenoma: Results in a Korean Population Receiving Screening Colonoscopy.

An association between serum uric acid and cancer risk has been noted over the past few decades. There is ongoing debate about whether hyperuricemia represents an independent risk factor for colorectal neoplasm. We investigated the association between serum uric acid and prevalence of colorectal adenoma considering numerous confounding factors. A cross-sectional study was performed with individuals who underwent a routine health check-up examination, including a screening colonoscopy and blood chemistry. The association between serum uric acid and prevalence of colorectal adenoma was estimated from the results of a logistic regression analysis. Of the 1,066 participants, 402 had colorectal adenoma (37.7%). In univariate models, the prevalence of colorectal adenoma was higher in participants in the fourth quartile uric acid level, compared to those in the first quartile uric acid level (OR, 1.67; 95% CI, 1.17-2.42; p=0.004). However, no significant association was detected between serum uric acid and prevalence of colorectal adenoma in multiple logistic regression analysis. A number of metabolic syndrome components exhibited a strong association with the prevalence of colorectal adenoma in the multivariate model (OR, 3.46 for highest vs. lowest; 95% CI, 1.30-9.20; p=0.021). Moreover, serum uric acid was strongly associated with metabolic syndrome-associated variables, including waist circumference, fasting blood glucose, systolic blood pressure, diastolic blood pressure, triglyceride, and high-density lipoprotein. Uric acid is not an independent risk factor for colorectal adenoma but is a risk indicator for metabolic syndrome-related colorectal adenoma.

Gut microbiome and colorectal adenomas.

The trillions of bacteria that naturally reside in the human gut collectively constitute the complex system known the gut microbiome, a vital player for the host's homeostasis and health. However, there is mounting evidence that dysbiosis, a state of pathological imbalance in the gut microbiome is present in many disease states. In this review, we present recent insights concerning the gut microbiome's contribution to the development of colorectal adenomas and the subsequent progression to colorectal cancer (CRC). In the United States alone, CRC is the second leading cause of cancer deaths. As a result, there is a high interest in identifying risk factors for adenomas, which are intermediate precursors to CRC. Recent research on CRC and the microbiome suggest that modulation of the gut bacterial composition and structure may be useful in preventing adenomas and CRC. We highlight the known risk factors for colorectal adenomas and the potential mechanisms by which microbial dysbiosis may contribute to the etiology of CRC. We also underscore novel findings from recent studies on the gut microbiota and colorectal adenomas along with current knowledge gaps. Understanding the microbiome may provide promising new directions towards novel diagnostic tools, biomarkers, and therapeutic interventions for CRC.

Visceral abdominal fat measured by computed tomography is associated with an increased risk of colorectal adenoma

We investigated whether visceral adipose tissue (VAT) measured by computed tomography (CT) is a risk factor for colorectal adenoma. For a total of 1,328 patients (857 without adenoma, 471 with colorectal adenoma) undergoing colonoscopy and CT, associations between colorectal adenoma and body mass index (BMI), VAT area and subcutaneous adipose tissue (SAT) were assessed using odds ratios (ORs) with 95% confidence intervals (CIs) adjusted for age, sex, family history, smoking, alcohol intake, diabetes mellitus, aspirin use and nonsteroidal anti-inflammatory drug use. Multivariate analysis showed that colorectal adenoma was marginally associated (p=0.06) with BMI, but not with SAT, while it was significantly associated with VAT and the VAT to SAT ratio (VAT/SAT) for both categorical data and trend (p<0.05). When the obesity indices were considered simultaneously, colorectal adenoma remained significantly associated with VAT and VAT/SAT (p<0.05), but not BMI and SAT. In patients with colorectal adenoma, the adjusted OR for the highest quartiles of VAT and VAT/SAT was 1.90 (95% CI 1.16-3.13) and 2.25 (95% CI 1.49-3.41), respectively, compared to the lowest quartiles. Only VAT area was significantly associated with colorectal adenoma in both men and women (p<0.05). Proximal, multiple and advanced adenomas had significantly higher VAT areas (p<0.05) than distal, solitary and nonadvanced adenomas. Our findings implicate abdominal VAT in the development and progression of colorectal adenoma, and it was better obesity index for colorectal adenoma than BMI in both sexes.

Serum folate and colorectal adenoma in Korean adults (628.18)

We investigated the association between serum folate levels and colorectal adenoma in a case‐control study of Korean adults. Participants underwent colonoscopy, and provided blood specimens and information on their socio‐demographic status and other risk factors for colorectal adenoma in a university hospital. Serum folate levels were measured by using the electrochemiluminescence immunoassay (ECLIA). Colorectal adenoma cases were determined through colonoscopy and histologic examinations. We included 113 cases (58 men and 55 women) of colorectal adenoma and 255 controls (69 men and 186 women). We calculated the odds ratios (ORs) and 95% confidence intervals (CIs) using a multivariate logistic regression model. After adjusting for potential confounding factors, we found no significant association between serum folate levels and colorectal adenoma; multivariate ORs (95% CIs) for the highest tertile compared to the lowest tertile were 0.86 (0.31 to 2.39) in men and 1.12 (0.51 to 2.46) in women. In summary, we did not observe that serum folate levels were associated with colorectal adenoma in Korean adults.Grant Funding Source: This study was supported by National Research Foundation of Korea (2011‐0011028)

Impact of HIV Infection on Colorectal Tumors

Non-AIDS defining cancer has recently become a major problem in HIV-infected patients. Little has been reported on whether HIV infection is a risk factor for colorectal adenoma, especially in Asians. The study was conducted under a prospective cross-sectional design and included all adults who underwent colonoscopy. Subjects were matched by age and sex to compare the prevalence of colorectal adenoma, adenocarcinoma, polyps, and other tumors. Detailed risk factors were assessed, including lifestyle habits, medications, comorbidities, gastrointestinal symptom rating scale, HIV-associated factors, and human papillomavirus infection. To evaluate the effects of HIV infection on adenoma, the odds ratio (OR) was estimated by multivariate logistic regression. A total of 177 HIV-infected patients and 177 controls were selected for analysis. No significant difference was noted in the prevalence of adenoma (n = 29 vs. 40, P = 0.14). Multivariate analysis adjusted by baseline demographics and risk factors showed that HIV is not associated with increased risk of adenoma (adjusted OR = 0.66, P = 0.16). Kaposi's sarcoma was more common in HIV-infected patients (n = 6 vs. 0, P = 0.03). Among HIV-infected patients, advanced age was an independent and significant risk factor for adenoma (adjusted OR = 2.28, P < 0.01). CD4 count, HIV-RNA, history of antiretroviral treatment, and oncogenic human papillomavirus infection were not risk factors for adenoma. HIV infection was not identified as risk for adenoma in Asian patients. However, advanced age was independently associated with increased risk of adenoma. HIV-infected patients should not miss screening opportunity for colorectal adenoma and other gastrointestinal malignancies.