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Background and Aims: Colonic diverticulosis (CD) is among the most common conditions of the large bowel. Several factors have been associated with an increased risk of CD and its complications, including advanced age, obesity, physical inactivity, and a low-fiber diet. Available data is conflicting and a comprehensive analysis of different bowel, dietary and environmental habits linked with CD is lacking. We aimed to investigate the relationship between potential risk factors and CD prevalence using full data from a colonoscopy-based cross-sectional study in Europe., Methods: The study was conducted at three tertiary referral centers in Germany and Lithuania. It included consecutive adult patients referred for routine colonoscopy who completed a detailed questionnaire on our considered multiple risk factors for diverticulosis and diverticulitis, including dietary and environmental factors, and bowel habits., Results: The study included 1,333 patients, 696 women and 635 men. Colonic diverticulosis was diagnosed in 858 (64%) of patients. Multivariate analysis revealed that age (OR: 1.08, 95%CI: 1.06-1.10, p<0.001) and obesity (OR: 1.05, 95%CI: 1.02-1.09, p=0.004) were associated with CD. We also revealed new risk factors for CD: increased frequency of bowel movements (OR: 0.10, 95%CI: 0.03-0.33, p<0.001) and feeling of incomplete bowel emptying (OR: 2.05, 95%CI: 1.47-2.87, p<0.001). Older participants had reduced odds (OR: 0.921, 95 CI: 0.89-0.95, p<0.05) of diverticulitis compared to younger subjects. Feeling of incomplete bowel emptying after defecation was associated with increased odds (OR: 2.769, 95% CI 1.35-5.7, p<0.006) for diverticulitis. Moreover, participants with a higher educational status had increased odds (OR: 2.453, 95%CI: 1.31-4.59, p=0.005) for diverticulitis compared to the lower education group., Conclusions:  Study shows that older age, obesity, frequency of bowel movements, and feeling of incomplete bowel emptying are associated with the risk of CD. Furthermore, older age, feeling of incomplete bowel emptying, and higher education were associated with the risk of diverticulitis among CD patients.

Colonic diverticulosis is a very common condition. Many patients develop diverticulitis or other complications of diverticular disease. Recent genome-wide association studies (GWAS) consistently identified three major genetic susceptibility factors for both conditions, but did not discriminate diverticulititis and diverticulosis in particular due the limitations of registry-based approaches. Here, we aimed to confirm the role of the identified variants for diverticulosis and diverticulitis, respectively, within a well-phenotyped cohort of patients who underwent colonoscopy. Risk variants rs4662344 in Rho GTPase-activating protein 15 (ARHGAP15), rs7609897 in collagen-like tail subunit of asymmetric acetylcholinesterase (COLQ) and rs67153654 in family with sequence similarity 155 A (FAM155A) were genotyped in 1,332 patients. Diverticulosis was assessed by colonoscopy, and diverticulitis by imaging, clinical symptoms and inflammatory markers. Risk of diverticulosis and diverticulitis was analyzed in regression models adjusted for cofactors. Overall, the variant in FAM155A was associated with diverticulitis, but not diverticulosis, when controlling for age, BMI, alcohol consumption, and smoking status (OR adjusted 0.49 [95% CI 0.27-0.89], p = 0.002). Our results contribute to the assessment specific genetic variants identified in GWAS in the predisposition to the development of diverticulitis in patients with diverticulosis.

Background: Colonic diverticulosis is one of the most common gastroenterological disorders. Although diverticulosis is typically benign, many individuals develop diverticulitis or other aspects of diverticular disease. Diverticulosis is thought to stem from a complex interaction of environmental, dietary, and genetic factors; however, the contributing genetic factors remain unknown., Objective: The aim of our present study was to determine the role of genetic variants within genes encoding for collagens of the connective tissue in diverticulosis., Design: This was a transsectional genetic association study., Settings: This study was conducted at three tertiary referral centers in Germany and Lithuania., Patients: Single-nucleotide polymorphisms in COL3A1 (rs3134646, rs1800255) and COL1A1 (rs1800012) were genotyped in 422 patients with diverticulosis and 285 controls of white descent by using TaqMan assays., Main Outcome Measures: The association of colonoscopy-proven diverticulosis with genetic polymorphisms with herniations was assessed in multivariate models., Results: The rs3134646, rs1800255, and rs1800012 variants were significantly associated with the risk of developing diverticulosis in the univariate model; however, these associations were not significant in the multivariate logistic regression analysis including additional nongenetic variables. When selectively analyzing sexes, the genotype AA (AA) in rs3134646 remained significantly associated with diverticulosis in men (OR, 1.82; 95% CI, 1.04-3.20; p = 0.04)., Limitations: Because a candidate approach was used, additional relevant variants could be missed. Within our cohort of patients with diverticulosis, only a small proportion had diverticular disease and thus, we could not examine the variants in these subgroups. Functional studies, including the analysis of the involved collagens, are also warranted., Conclusions: Our study shows that a variant of COL3A1 (rs3134646) is associated with the risk of developing colonic diverticulosis in white men, whereas rs1800255 (COL3A1) and rs1800012 (COL1A1) were not associated with this condition after adjusting for confounding factors. Our data provide novel valuable insights in the genetic susceptibility to diverticulosis. See Video Abstract at http://links.lww.com/DCR/A504.