Colonic diverticula are located predominantly on the right side in Asia and on the left side in Europe and the United States. Factors associated with uncomplicated colonic diverticulosis and its distribution pattern have been unknown. Our aims are to investigate the prevalence and risk factors for uncomplicated colonic diverticulosis. We conducted a prospective cross-sectional study in adults who underwent colonoscopy. Alcohol, alcohol related flushing, smoking, medications, and comorbidities were assessed by interview on the colonoscopy day. Alcohol consumption was categorized as nondrinker, light (1–180 g/week), moderate (181–360 g/week), and heavy (≥361 g/week). Smoking index was defined as the number of cigarettes per day multiplied by the number of smoking years and categorized as nonsmoker, <400, 400–799, and ≥800. A total of 2,164 consecutive patients were enrolled. Overall, 542 patients (25.1%) had uncomplicated colonic diverticulosis located on the right side (50%), bilaterally (29%), and on the left side (21%). Univariate analysis revealed age, male, smoking index, alcohol consumption, aspirin use, anticoagulants use, corticosteroid use, hypertension, and atherosclerotic disease as factors significantly associated with diverticulosis. Alcohol related flushing was not associated with the disease. Multivariate analysis showed increasing age (P<0.01), increasing alcohol consumption (P<0.01) and smoking (P<0.01), and atherosclerotic disease (P<0.01) as significantly associated factors. Alcohol and smoking were associated with right-sided and bilateral diverticula. In conclusion, one in four Japanese adults have colonic diverticulosis (50% right-sided). Age, alcohol consumption, and smoking were found to be significant risk factors for uncomplicated colonic diverticulosis, particularly right-sided and bilateral.

The aim of this study was to identify predictors for the identification of stigmata of recent hemorrhage (SRH) on colonic diverticula. Several factors influence the identification of SRH in the diagnosis of colonic diverticular bleeding. A total of 396 patients hospitalized for lower gastrointestinal bleeding were analyzed. Comorbidities, medications, timing of colonoscopy [48 h], preparation, expert colonoscopist, use of a cap, use of a water-jet scope, total colonoscopy, and procedure time (over 60 min) were assessed. A multivariable logistic regression model was used to estimate odds ratio (OR) and 95% confidence interval (CI). Two hundred fifteen patients were diagnosed with colonic diverticular bleeding and 37 (17%) were identified with SRH. Urgent colonoscopy (OR, 8.4; 95% CI, 2.3-30; P48 hours groups (1.0%, P<0.01), showing a tendency to decrease with time (P<0.01 for trend). Factors of urgent colonoscopy, expert colonoscopist, use of a cap, and use of water-jet scope are useful for identifying SRH diverticula.

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.