Recent trends in the prevalence and distribution of colonic diverticula in Japan evaluated using computed tomography colonography.

BACKGROUND: Computed tomography colonography (CTC) may be superior to colonoscopy and barium enema for detecting diverticula. However, few studies have used CTC to diagnose diverticula. AIM: To evaluate the current prevalence and distribution of colonic diverticula in Japan using CTC. METHODS: This study was conducted as part of the Japanese National Computed Tomographic Colonography Trial, which included 1181 participants from 14 hospitals in Japan. We analyzed the prevalence and distribution of colonic diverticula and their relationships with age and sex. The relationship between the diverticula and the length of the large intestine was also analyzed. RESULTS: Diverticulosis was present in 48.1% of the participants. The prevalence of diverticulosis was higher in the older participants (P < 0.001 for trend). The diverticula seen in younger participants were predominantly located in the right-sided colon. Older participants had a higher frequency of bilateral type (located in the right- and left-sided colon) diverticulosis (P < 0.001 for trend). The length of the large intestine with multiple diverticula in the sigmoid colon was significantly shorter in those without diverticula (P < 0.001). CONCLUSION: The prevalence of colonic diverticulosis in Japan is higher than that previously reported. The prevalence was higher, and the distribution tended to be bilateral in older participants.

Association of Colonic Diverticula with Colorectal Adenomas and Cancer.

Background and Objectives: Conflicting evidence is reported regarding any association between colonic diverticula with colorectal adenomas or cancer. The present study aimed to evaluate, in a cohort of Caucasian patients, the association between colonic diverticula and colorectal polyps and cancer. Materials and Methods: All consecutive patients undergoing colonoscopy at our institution were included in the study. The presence and location of diverticula, polyps, and cancers were recorded. Histologically, polyps were classified as adenoma (with low or high dysplasia), hyperplastic, or inflammatory. The relative risk of the association of polyps and cancer with diverticula was assessed. Multiple logistic regression analyses, including age, sex, family history for colorectal cancer (CRC), and family history for diverticula, were carried out. Results: During the study period, 1490 patients were enrolled; 37.2% (n = 555) showed colonic diverticula or polyps or CRC (308 males, mean age 66 years). Particularly, 12.3% (n = 183) patients presented only diverticula, 13.7% (n = 204) only polyps or cancer, 11.3% (n = 168) both diseases, and 62.7% (n = 935) neither diverticula nor polyps and cancer. A total of 38 patients presented colorectal cancer, 17 of which had also diverticula. A significant increase in relative risk (RR 2.81, 95% CI 2.27-3.47, p < 0.0001) of colorectal adenoma and cancer in patients with colonic diverticula was found. At multivariate analysis, only diverticula resulted to be significantly associated with colorectal adenomas and cancer (Odds Ratio, OR 3.86, 95% CI 2.90-5.14, p < 0.0001). Conclusions: A significant association of colonic diverticula with colorectal adenoma or cancer was found. This implies that patients with colonic diverticula require a vigilant follow-up procedure for the prevention of colorectal cancer from those applicable to the general population.

Colon Cancer and Diverticular Disease Association: a Case-Control Study.

PURPOSE: To determine if there is an association between diverticular disease and colon cancer diagnoses with a secondary outcome of assessing other known risk factors for colon cancer. Colon cancer and diverticular disease have many shared symptoms and risk factors; the association between the two has been debated for many years. METHODS: 36 cases of colon cancer and 144 age- and sex-matched controls were identified from records at an outpatient endoscopy center in Georgia. These cases and controls then were subject to a retrospective chart review to obtain any known risk factor data points for both diverticular disease and colon cancer. A traditional conditional logistic regression and a stepwise conditional logistic regression model were used to analyze the data using significant data points (P < 0.05). RESULTS: The final stepwise model found that systolic blood pressure (aOR = 1.027, 95% CI = 1.001 to 1.053), history of polyps (aOR = 0.106, 95% CI = 0.029 to 0.387), exercise (aOR = 0.311, 95% CI = 0.029 to 0.387), and history of diverticular disease (aOR = 0.269, 95% CI = 0.091 to 0.795) were protective factors significantly associated with colon cancer. CONCLUSIONS: Presence and history of the removal of colorectal polyps, presence or history of diverticular disease, and exercise pose as protective factors against development of colon cancer.

Alpha-1-antitrypsin deficiency (carrier) as possible risk factor for development of colonic diverticula. A multicentre prospective case-control study: the ALADDIN study.

AIM: Connective tissue changes due to ageing or diseases leading to changes in the colonic wall are one theory for the development of diverticula. Alpha-1-antitrypsin (A1AT), a protease inhibitor that protects connective tissue, possibly plays a role in the aetiology of diverticulosis. The aim of this study was to explore associations between the development of diverticula and A1AT deficiency. METHODS: This was a multicentre prospective case-control study. A total of 221 patients aged ≥ 60 years with acute abdominal pain undergoing abdominal CT were included and analysed. Patients with diverticula were defined as the research group, patients without diverticula as controls. Genotype analysis for A1AT deficiency was performed. RESULTS: Twenty-six of 221 (11.8%) patients were diagnosed with (being a carrier of) A1AT deficiency. A non-significant difference in prevalence between patients with and without diverticula was found, 20 (13.9%) of 144 vs 6 (7.8%) of 77, respectively, with a crude OR of 1.9 (95% CI 0.7-5.0; P = 0.186) and after adjustment for confounders an adjusted OR of 1.5 (95% CI 0.5-4.0; P = 0.466). A non-significant difference in 30-day mortality rate from acute diverticulitis between A1AT deficient patients (or carriers) and those without was observed: two (22.2%) of nine patients with A1AT deficiency vs 1 (1.8%) of 55 without. CONCLUSION: We found no convincing evidence that A1AT deficiency plays a role in the aetiology of diverticulitis, although deficient patients and carriers had a higher mortality when experiencing diverticulitis. Diverticulitis is a multifactorial disease and larger numbers may be needed to explore the role of A1AT deficiency among other contributing factors.

Epidemiology of colonic diverticula and recent advances in the management of colonic diverticular bleeding.

There is the East-West paradox in prevalence and phenotype of colonic diverticula, but colonic diverticular bleeding (CDB) is the most common cause of acute lower gastrointestinal bleeding worldwide. Death from CDB can occur in elderly patients with multiple comorbidities, thus the management of CDB is clinically pivotal amid the aging populations in the East and West. Colonoscopy is the key modality for managing the condition appropriately; however, conventional endoscopic hemostasis by thermal coagulation and clipping cannot achieve the expected results of preventing early rebleeding and conversion to intensive intervention by surgery or transcatheter arterial embolization. Ligation therapy by endoscopic band ligation or endoscopic detachable snare ligation has emerged recently to enable more effective hemostasis for CDB, with an early rebleeding rate of approximately 10% and very rare conversion to intensive intervention. Ligation therapy might in turn reduce long-term rebleeding rates by eliminating the target diverticulum itself. Adverse events have been reported with ligation therapy including diverticulitis of the ascending colon in less than 1% of cases and perforation of the sigmoid colon in a few cases, thus more data are necessary to verify the safety of ligation therapy. Endoscopic hemostasis is indicated only for diverticulum with stigmata of recent hemorrhage (SRH), but the detection rates of SRH are relatively low. Therefore, efforts to increase detection are also key for improving CDB management. Urgent colonoscopy and triage by early contrast-enhanced computed tomography may be candidates to increase detection but further data are necessary in order to make a conclusion.

Recent Trends in Treatment for Colonic Diverticular Bleeding in Japan.

BACKGROUND: In both Western countries and in Japan, the incidence of colonic diverticular bleeding has increased with increased use of antithrombotic and nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, the Japan Gastroenterological Association issued guidelines for colonic diverticular bleeding and colonic diverticulitis in Japanese in 2017 and in English in 2019. However, the guidelines contain unresolved problems. Herein, we review the recent treatment trends for colonic diverticular bleeding in Japan. SUMMARY: Colonic diverticular bleeding necessitates frequent blood transfusions due to rebleeding, and patients require prolonged hospitalization. Endoscopic treatment plays an important role in treating diverticular bleeding. Currently, endoscopic band ligation (EBL) and endoscopic clipping are used in Japan for diverticular hemorrhage when the source of the hemorrhage is identified. EBL results in significantly lower early (<30 days) and 1-year rebleeding rates and long-term recurrence rates compared with endoscopic clipping. Furthermore, the proportion of patients requiring transcatheter arterial embolization or surgery after EBL is significantly lower than that following endoscopic clipping. Several reports state that EBL is superior to endoscopic clipping; however, EBL has associated complications, and it is necessary to carefully consider the individual patient. Key Messages: EBL is superior to endoscopic clipping regarding short- and long-term rebleeding rates and the rate of transition to surgery and embolization. Methods for preventing diverticular hemorrhage have not been established, but NSAIDs should be discontinued if possible. Prevention strategies for diverticular bleeding need to be evaluated in studies with large sample sizes.

Gender, Age, and Concomitant Diseases of Colorectal Diverticulum in China: A Study of 7,964 Cases.

AIM: To analyze the epidemiological features of colorectal diverticulum (CRD) in China. METHODS: We retrospectively analyzed CRD patients in 8 tertiary hospitals located in 5 regions of China from 2000 to 2016. The detection rates, number and distribution, demographic information, concomitant disorders, and their associations were investigated. RESULTS: Of 3,446,118 cases, 7,964 (2.3%) were CRD with a mean age of 56 years (11-92 years). The detection rate increased yearly and with increasing age. Males had a higher detection rate than females (3.0 vs. 1.47%, p < 0.01) and 1.8-times higher increase rate. The detection rate increased with age; however, females of > 60 years had a 2.8-times increasing rate than males. CRD occurred most frequently in the right-side colon, followed by rectum. Multiple diverticula were common in males and increased with age, with a 3-times higher increase rate than single lesion. Single-segment CRD occurred more frequently in males than in females (80.1 vs. 76.4%, p < 0.01). Concurred colon polyps were seen in 51.05% cases. CONCLUSION: CRD detection rates increased annually and with age, particularly in senior females in China. Multiple diverticula were common in males and increased with age. CRD was predominant in the right-side colon. Polyps are the most common comorbidity associated with CRD.

Diagnosis and Treatment of Colonic Diverticular Disease: Position Paper of the Romanian Society of Gastroenterology and Hepatology.

BACKGROUND AND AIMS: Diverticular disease of the colon is a common clinical condition in developed countries, and is associated with significant (direct and indirect) economic burden. The aim of this Position Paper is to provide clinical guidance for appropriate definition, prevalence, risk factors, diagnosis, and treatment of colonic diverticular disease. METHODS: A working group of recognized experts established by the Board of the Romanian Society of Gastroenterology and Hepatology (RSGH) screened the literature and the available guidelines on colonic diverticular disease. Statements were formulated based on literature evidence. These statements were discussed within the working group and decision for each of them was taken by consensus. RESULTS: Thirty two statements were elaborated. The grade of recommendation, according to the level of evidence was established for each statement. Short comments with literature support accompany each statement. CONCLUSION: This Position Paper represents a practical guide for clinicians dealing with patients affected by colonic diverticular disease.

Mesalazine to treat symptomatic uncomplicated diverticular disease and to prevent acute diverticulitis occurrence. A systematic review with meta-analysis of randomized, placebo-controlled trials.

BACKGROUND AND AIMS: Symptomatic Uncomplicated Diverticular disease (SUDD) affects about 25% of patients harboring colonic diverticula. We assessed the effectiveness of mesalazine in improving symptoms (namely abdominal pain, primary outcome) and in preventing diverticulitis occurrence (secondary outcome) in patients with SUDD. METHODS: Pertinent studies were selected from the Medline and the Cochrane Central Register of Controlled Trials. Only randomized clinical trials (RCTs) (irrespective of language, blinding, or publication status), which compared mesalazine, irrespective of the dosage assumption, with placebo in SUDD were evaluated. RESULTS: Four RCTs enrolled 379 patients, 197 treated with mesalazine and 182 with placebo. Two studies provided data on symptom relief according to definition: it was achieved in 97/121 (80%) patients in the mesalazine group and in 81/129 (62.7%) patients in the placebo group (OR 0.43; 95% CI 0.24-0.75; p=0.003 in favour of the mesalazine group). Two studies provided information regarding occurrence of diverticulitis during follow-up. It occurred in 23/119 (19.3%) patients in the mesalazine group and in 34/102 (33.3%) patients in the placebo group (OR 0.35; 95% CI 0.17-0.70; p=0.003 in favour of the mesalazine group). CONCLUSIONS: Treatment with mesalazine seems to be effective in achieving symptom relief and in the primary prevention of diverticulitis in patients with SUDD.

Risk of colorectal adenomas, advanced adenomas and cancer in patients with colonic diverticular disease: Systematic review and meta-analysis.

BACKGROUND AND AIM: Diverticular disease and colorectal neoplasia are common digestive disorders worldwide. Both diseases share epidemiological trends and certain risk factors including advancing age, physical inactivity, and Western diet and lifestyle. Studies assessing the association between these diseases reported inconsistent results. Thus, we conducted a systematic review and meta-analysis to determine the association between diverticular disease and colorectal adenomas, advanced adenomas and cancer. METHODS: A comprehensive search of the databases MEDLINE and EMBASE was done from inception through March 2016. Inclusion criterion was the observational studies' assessment of the association between diverticular disease and colorectal neoplasia in adult participants. Pooled OR and 95% confidence interval (CI) were calculated using a random effect. RESULTS: Data were extracted from 14 observational studies (11 cross-sectional studies, one case-control study and two cohort studies). Diverticular disease was associated with increased odds of adenomas (OR = 1.67, 95% CI 1.27-2.21, 10 studies), but not associated with advanced adenomas (OR = 1.19, 95% CI 0.88-1.62, I2  = 52%, four studies) or colorectal cancer (OR = 1.36, 95% CI 0.47-3.92, I2  = 98%, seven studies). CONCLUSIONS: Our meta-analysis demonstrated that diverticular disease was associated with colorectal adenomas. Colonoscopists should be aware of this association and carefully examine the entire large bowel in individuals with diverticulosis.

Diverticular Disease in the Primary Care Setting.

Diverticular disease is a chronic and common condition, and yet the impact of diverticular disease in primary care is largely unknown. The diagnosis of diverticular disease relies on the demonstration of diverticula in the colon, and the necessary investigations are often not available in primary care. The specificity and sensitivity of symptoms, clinical signs and laboratory tests alone are generally low and consequently the diagnostic process will be characterized by uncertainty. Also, the criteria for symptomatic uncomplicated diverticular disease in the absence of macroscopic inflammation are not clearly defined. Therefore both the prevalence of diverticular disease and the incidence of diverticulitis in primary care are unknown. Current recommendations for treatment and follow-up of patients with acute diverticulitis are based on studies where the diagnosis has been verified by computerized tomography. The results cannot be directly transferred to primary care where the diagnosis has to rely on the interpretation of symptoms and signs. Therefore, one must allow for greater diagnostic uncertainty, and safety netting in the event of unexpected development of the condition is an important aspect of the management of diverticulitis in primary care. The highest prevalence of diverticular disease is found among older patients, where multimorbidity and polypharmacy is common. The challenge is to remember the possible contribution of diverticular disease to the patient's overall condition and to foresee its implications in terms of advice and treatment in relation to other diseases.

Distribution and Characteristics of Colonic Diverticula in a United States Screening Population.

BACKGROUND & AIMS: Colonic diverticula are the most common finding from colonoscopy examinations. Little is known about the distribution of colonic diverticula, which are responsible for symptomatic and costly diverticular disease. We aimed to assess the number, location, and characteristics of colonic diverticula in a large US screening population. METHODS: We analyzed data from a prospective study of 624 patients (mean age, 54 years) undergoing screening colonoscopy at the University of North Carolina Hospital from 2013 through 2015. The examination included a detailed assessment of colonic diverticula. To assess the association between participant characteristics and diverticula, we used logistic regression to estimate odds ratios and 95% confidence intervals. RESULTS: Of our population, 260 patients (42%) had 1 or more diverticula (mean number, 14; range, 1-158). Participants with diverticula were more likely to be older, male, and have a higher body mass index than those without diverticula. The distribution of diverticula differed significantly by race. Among white persons, 75% of diverticula were in the sigmoid colon, 11% in the descending splenic flexure, 6% in the transverse colon, and 8% were in the ascending colon or hepatic flexure. In black persons 64% of diverticula were in the sigmoid colon, 8% in the descending colon or splenic flexure, 7% in the transverse colon, and 20% in the ascending colon or hepatic flexure (P = .0008). The proportion of patients with diverticula increased with age: 35% were 50 years or younger, 40% were 51-60 years, and 58% were older than 60 years. The proportion of patients with more than 10 diverticula increased with age: 8% were 50 years or younger, 15% were 51-60 years, and 30% were older than 60 years. CONCLUSIONS: Older individuals not only have a higher prevalence of diverticula than younger individuals, but also a greater density, indicating that this is a progressive disease. Black persons have a greater percentage of their diverticula in the proximal colon and fewer in the distal colon compared with white persons. Understanding the distribution and determinants of diverticula is the first step in preventing diverticulosis and its complications.

Predictive factors for colonic resection in patients less than 49 years with symptomatic diverticular disease.

BACKGROUND: Diverticular disease is a condition strongly associated with low-fiber intake and obesity. There have been reports of an increasing incidence in younger individuals ranging from 12% to 21% of all cases. The aim of this study was to evaluate the management of complicated diverticular disease in patients less than 49 years and attempt to identify factors predictive of a more virulent course. METHODS: An analysis of a prospectively updated database of all patients admitted with a primary diagnosis of acute diverticulitis from 2005 to 2013 was performed. Data collected included age, length of stay, inflammatory markers on admission, use of computed tomography (CT), and Hinchey Classification. SPSS version 22 was used for statistical analysis, and a P value of .05 or less was considered significant. RESULTS: A total of 120 (54 female and 66 male) patients less than 49 (28 to 49, 42.1) years were noted to have a diagnosis of acute diverticulitis. Twelve patients (10%) required colonic resection for complicated diverticulitis. Histological evaluation revealed 5 cases of stricture, 2 obstruction, and 5 perforations. On multivariate analysis, predictors of operative intervention and/or colonic resection included, (hazard ratio [95% confidence interval]) patients aged 40 to 49 years (.92 [.9 to .95]) and elevated C-reactive protein on index admission (1.4 [1.32 to 1.54]). Females were less likely to undergo colonic resection compared with males (1.18 [1.15 to 1.2]). Median length of stay was 4 days (1 to 48) for patients managed nonoperatively and 13 days (5 to 27) for those who underwent surgery. CONCLUSIONS: Most younger patients with acute diverticulitis can be treated successfully by conservative means. However, a proportion of patients require aggressive surgical management.

Prevalence and distribution of colonic diverticula assessed with CT colonography (CTC).

OBJECTIVES: This study aimed to evaluate the prevalence of colonic diverticula according to age, gender, distribution, disease extension and symptoms with CT colonography (CTC). METHODS: The study population included 1091 consecutive patients who underwent CTC. Patients with diverticula were retrospectively stratified according to age, gender, clinical symptoms and colonic segment involvement. Extension of colonic diverticula was evaluated using a three-point quantitative scale. Using this data, a multivariate regression analysis was applied to investigate the existence of any correlation among variables. RESULTS: Colonic diverticula were observed in 561 patients (240 men, mean age 68 ± 12 years). Symptomatic uncomplicated diverticular disease (SUDD) was present in 47.4% of cases. In 25.6% of patients ≤40 years, at least one diverticulum in the colon was observed. Prevalence of right-sided diverticula in patients >60 years was 14.2% in caecum and 18.5% in ascending colon. No significant difference was found between symptomatic and asymptomatic patients regarding diverticula prevalence and extension. No correlation was present between diverticula extension and symptoms. CONCLUSION: The incidence of colonic diverticula appears to be greater than expected. Right colon diverticula do not appear to be an uncommon finding, with their prevalence increasing with patient age. SUDD does not seem to be related to diverticula distribution and extension. KEY POINTS: Incidence of colonic diverticula appears to be greater than expected. Right colon diverticula do not appear to be an uncommon finding. SUDD does not seem to be related to diverticula distribution and extension.

The Gut in Older Patients on Peritoneal Dialysis.

Age-related changes in gastrointestinal symptoms need to be considered in peritoneal dialysis (PD) patients. A diminishing appetite is associated with aging and may be exacerbated by renal failure and PD treatment, meaning that attention to dietary adequacy is important in the older patient. Constipation and its treatment may increase the risk of peritonitis, but is important for comfort as well as trouble-free dialysis. Diverticulosis increases with age, and whilst there may be ethnic differences in the patterns of this condition, there is conflicting evidence regarding the risks of peritonitis associated with asymptomatic disease. Hernias, urinary incontinence, and prolapse are also common and made worse by PD, so it is important to know about these issues prior to starting. Whilst data around these topics are scant and some studies conflicting, further understanding these issues and considering mitigation strategies may improve technique survival and quality of life.

Increased Risk of Pyogenic Liver Abscess Among Patients With Colonic Diverticular Diseases: A Nationwide Cohort Study.

Whether patients with diverticular diseases exhibit a higher risk of developing pyogenic liver abscess (PLA) remains inconclusive.From the inpatient claims in Taiwan's National Health Insurance Research Database, we identified 54,147 patients diagnosed with diverticulosis in the 1998 to 2010 period and 216,588 controls without the disorder. The 2 cohorts were matched by age, sex, and admission year, and were followed up until the end of 2010 to estimate the risk of PLA.Overall, the incidence of PLA was 2.44-fold higher in the diverticular-disease group than in the controls (11.5 vs 4.65 per 10,000 person-year). The adjusted hazard ratio (aHR) of PLA was 2.11 (95% confidence interval [CI], 1.81-2.44) for the diverticular-disease group, according to a multivariate Cox proportional hazards regression model. The age-specific data showed that the aHR for the diverticular-disease group, compared with the controls, was the highest inpatients younger than 50 years old (aHR, 4.03; 95% CI, 2.77-5.85). Further analysis showed that the diverticular-disease group exhibited an elevated risk of PLA regardless of whether patients had diverticulitis.The patients with diverticular diseases exhibited a higher risk of PLA.

Variations in Laparoscopic Colectomy Utilization in the United States.

BACKGROUND: Recent published articles reported a wide geographic variation in the utilization of laparoscopic colectomy in the United States. OBJECTIVES: This study aimed to report the current rates of laparoscopic colon resection in different types of hospitals in the United States. DESIGN: The Nationwide Inpatients Sample database was used to examine the clinical data of patients undergoing elective colon resection for the diagnosis of colon cancer or diverticular disease from 2009 to 2012. SETTING: Multivariate regression analysis was performed to compare different hospital types and regions regarding the utilization of laparoscopy. PATIENTS: Patients undergoing elective colon resection for the diagnosis of colon cancer or diverticular disease from 2009 to 2012 were selected. MAIN OUTCOME MEASURES: The primary outcome measured was the rates of laparoscopic colon resection in different types of hospitals. RESULTS: We sampled a total of 309,816 patients who underwent elective colon resection. Of these, 171,666 (55.4%) had a laparoscopic operation. The utilization of a laparoscopic approach increased from 51.3% in 2009 to 59.3% in 2012. The increased utilization of a laparoscopic approach was seen in both urban (53.6% vs 61.6%) and rural hospitals (33.4% vs 42.3%), for colon cancer (45% vs 53.5%), and diverticular disease (61.9% vs 68.2%). The conversion rate to open surgery for diverticular disease was significantly higher than for colon cancer (adjusted odds ratio (AOR), 1.23; p < 0.01). After adjustment, urban hospitals (AOR, 2.13; p < 0.01), teaching hospitals (AOR, 1.13; p < 0.01), and large hospitals (AOR, 1.33; p < 0.01) had a greater utilization of laparoscopic surgery. LIMITATIONS: This study was limited by its retrospective nature. CONCLUSIONS: Although we have finally reached the point where a majority of patients undergoing an elective colectomy for diverticular disease and colon cancer receive a laparoscopic operation, there is wide variation in the implementation of laparoscopic surgery in colon resection in the United States. The utilization of a laparoscopic approach has associations with hospital factors such as size, teaching status of the hospital, and geographic location (urban vs rural).

A comparative analysis of colonoscopy findings in a Chinese and American tertiary hospital.

BACKGROUND/AIMS: To compare the colonoscopy findings of a tertiary Chinese hospital with those of an American tertiary hospital. MATERIALS AND METHODS: Hundred consecutive colonoscopies performed in August 2008 at the First Affiliated Hospital of Nanchang University in China and at the Emory University Hospital, United States of America, were investigated. The endoscopic findings and the histopathology results were statistically compared. RESULTS: The average age of Chinese patients who underwent colonoscopy in this study was 45.23±15.38 years, whereas that of American patients was 55.38±12.11 years; no difference in sex ratio was observed (p=0.202) between the two populations. Screening colonoscopy accounted for 38% of patients in the American group and zero patients in the Chinese group. Polyps and diverticula were the most common findings in both groups. Abnormal findings in the American patients were three times higher than those in the Chinese patients. Proximal colon polyps were more common in the American group. Conversely, proximal colon diverticula were more common in the Chinese group. The prevalence of non-neoplasm lesions was not different between the two groups (p=0.232); the prevalence of adenomas significantly increased in patients who were more than 50 years old in both groups and was higher in the American group (p=0.038). CONCLUSION: The prevalence of bowel diseases in American patients was higher than that in Chinese patients. Polyps and diverticula were the main bowel abnormalities in both groups. Chinese patients lacked awareness of colonoscopy screening and should be enhanced aged 50 years old or older, because the prevalence of advanced neoplasia was increased in this age group in both groups.