No distinct microbiome signature of irritable bowel syndrome found in a Swedish random population.

OBJECTIVE: The ethiopathogenesis of irritable bowel syndrome (IBS) is unknown. While a link to the gut microbiome is postulated, the heterogeneity of the healthy gut makes it difficult to draw definitive conclusions. We aimed to describe the faecal and mucosa-associated microbiome (MAM) and health correlates on a community cohort of healthy and IBS individuals with no colonoscopic findings. DESIGN: The PopCol study recruited a random sample of 3556 adults; 745 underwent colonoscopy. IBS was defined by Rome IV criteria and organic disease excluded. 16S rRNA gene sequencing was conducted on sigmoid biopsy samples from 376 representative individuals (63 IBS cases) and faecal samples from 185 individuals (32 IBS cases). RESULTS: While sigmoid MAM was dominated by Lachnospiraceae, faeces presented a higher relative abundance of Ruminococcaceae. Microbial richness in MAM was linearly correlated to that in faeces from the same individual (R²=0.255, p<3E-11) as was diversity (R²=0.06, p=0.0022). MAM diversity decreased with increasing body mass index (BMI; Pearson's r=-0.1, p=0.08) and poorer self-rated health (r=-0.15, p=0.007), but no other health correlates. Faecal microbiome diversity was correlated to stool consistency (r=-0.16, p=0.043). Several taxonomic groups were correlated to age, BMI, depression and self-reported health, including Coprococcus catus associated with lower levels of depression (r=-0.003, p=0.00017). The degree of heterogeneity observed between IBS patients is higher than that observed between healthy individuals. CONCLUSIONS: No distinct microbial signature was observed in IBS. Individuals presenting with low self-rated health or high BMI have lower gut microbiome richness.

Rates and characteristics of postcolonoscopy colorectal cancer in the Swedish IBD population: what are the differences from a non-IBD population?

OBJECTIVE: The rate of postcolonoscopy colorectal cancer (PCCRC) is considered a key quality indicator of colonoscopy; little is known about PCCRC in IBD. DESIGN: A population-based cohort study of colonoscopies in Sweden from 2001 to 2010 was conducted. Individuals with a colorectal cancer (CRC) detected within 36 months after a colonoscopy were identified and stratified on UC, Crohn's disease (CD) or non-IBD. The CRCs were classified as detected CRCs (dCRC) (0-6 months) or as PCCRCs (6-36 months). PCCRC rates were calculated by the number of false negative/(the number of true positive+the number of false negative) colonoscopies. Poisson regression analysis was employed to examine the association between PCCRC and IBD (CD and UC) diagnosis, age, gender, location, time period and comorbidities. RESULTS: We identified 348 232 colonoscopies in 270 918 individuals. Of these, 27 123 were performed on 14 597 individuals with CD, and 51 572 were performed on 26 513 individuals with UC. There were 13 317 CRCs in the non-IBD group, 133 in the CD group and 281 in the UC group. The PCCRC rate in the CD group was 28.3% and 41.0% in the UC group. The RR for a PCCRC was 3.82 (95% CI 2.94 to 4.96) in CD and 5.89 (95% CI 5.10 to 6.80) in UC, compared with non-IBD. The highest risk was observed among rectal cancer location in CD and in younger individuals with UC. CONCLUSION: The high rates of PCCRC in young patients with UC and for rectal cancer location in CD might affect future performance of IBD surveillance.

Identifying clinically relevant sliding hiatal hernias: a population-based endoscopy study.

OBJECTIVES: The clinical relevance of small to moderate sliding hiatal hernias is controversial. The aims of the present study were to (1) investigate which symptoms are associated with sliding hiatal hernias and (2) define the length of a sliding hiatal hernia at which gastrointestinal symptoms occur. METHODS: A study population representative of the general Swedish population answered a questionnaire regarding gastrointestinal symptoms and was investigated with an upper endoscopy. The length of any sliding hiatal hernia was measured. RESULTS: Only reflux-related symptoms were associated with length of the hiatal hernia (acid regurgitation OR 1.46, CI 1.19-1.79, heartburn OR 1.27, CI 1.05-1.54), and the association did not become significant until an axial hiatal hernia length of 2 cm. CONCLUSIONS: Only reflux symptoms could be attributed to sliding hiatal hernias. Hiatal hernias less than 2 cm should be considered clinically insignificant.

Quality of endoscopic surveillance of Lynch syndrome patients in a Swedish cohort.

Background and study aims Risk factors for colorectal cancer (CRC) in Lynch syndrome (LS) include sex, age, smoking, high body mass index (BMI), surveillance interval length, and risk genotype. The Boston Bowel Preparation Scale (BBPS) produces a standardized bowel cleanliness rating. A low BBPS score might be a risk factor for missed early lesions. The aim of this study was to investigate the correlation between BBPS score and adenoma detection (with known risk factors for CRC) and surveillance interval with CRC detection in LS patients. Methods A retrospective cohort study including 366 LS patients with 1,887 colonoscopies under surveillance in Stockholm, Sweden from 1989 to 2021 was conducted. Associations were tested using linear and logistic regression. Results We found no association between BBPS score and number of adenomas detected. A low BBPS score was found to be associated with older age (regression coefficient (coeff) -0.015; 95% confidence interval [CI] -0.026 to -0.004; P = 0.007) and obesity (coeff = -0.48; 95% CI: -0.89 to -0.062; P = 0.024). A higher number of detected adenomas was associated with older age (coeff = 0.008; 95% CI 0.004 to 0.012; P < 0.001), male sex (coeff = 0.097; 95% CI 0.008 to 0.19; P = 0.033) and CRC (coeff = 0.28; 95% CI 0.061 to 0.50; P = 0.012). Surveillance interval length was not significant in CRC detection. Conclusions Bowel cleanliness was not associated with adenoma detection and was less likely achieved in patients who were older and had higher BMI. Adenoma detection was associated with older age and male sex. The results indicate the need for better adherence to guidelines and attention to older age groups, men, and patients with obesity.

Prevalence of colonic neoplasia and advanced lesions in the normal population: a prospective population-based colonoscopy study.

OBJECTIVE: There are few prospective studies of the prevalence of colonic neoplasia in the normal population. In order to properly evaluate screening-protocols for colorectal cancer in risk groups (e.g., older subjects or those with a family history), it is essential to know the prevalence of adenomas and cancer in the normal population. METHODS: A prospective population-based colonoscopy study on 745 individuals born in Sweden aged 19-70 years was conducted (mean age 51.1 years). All polyps seen were retrieved and examined. RESULTS: Out of the 745 individuals 27% had polyps, regardless of kind. Adenomas were found in 10% of the individuals and finding of adenomas was positively correlated to higher age. Men had adenomas in 15% and women in 6% of the cases. Women had a right-sided dominance of adenomas. Hyperplastic polyps were seen in 21% of the individuals. The presence of hyperplastic polyps was significantly positively correlated to the presence of adenomas. Advanced adenomas were seen in 2.8% of the study participants, but no cancers were detected. CONCLUSION: One in 10 healthy subjects had an adenoma but advanced adenomas were uncommon. Men and women have a different adenoma prevalence and localization. The results provide baseline European data for evaluating colonoscopy screening-protocols for colorectal cancer risk groups, and the findings may have implications for colon cancer screening in the normal, otherwise-healthy population.

Perforations and bleeding in a population-based cohort of all registered colonoscopies in Sweden from 2001 to 2013.

Background: The rates of perforation and bleeding are important quality measures of colonoscopy performance. Objective: The objective of this article is to assess the frequency of colonoscopy-related bleeding and perforation in Swedish counties and to relate these findings to patient characteristics. Method: Data on 593,308 colonoscopies performed on adults from 2001 to 2013 were retrieved from Swedish inpatient and outpatient registers. Covariates were assessed in a multivariate Poisson regression model. The correlation between perforation and bleeding was calculated with Pearson's bivariate correlation formula. Results: The relative frequency of bleeding and perforation vary across counties (bleeding: 0.02%-0.27%; perforation: 0.02%-0.27%). There were significant positive correlations between the relative frequency of bleeding and perforation at the county level, both including (r = 0.792, p < 0.001) and excluding polypectomies r = 0.814 (p < 0.001). The relative risks of these conditions in the counties ranged from 0.12, p < 0.001, to 1.53, p = 0.05 (bleeding) and from 0.17, p = 0.002, to 2.42, p < 0.001 (perforation). Conclusions: There are substantial differences in colonoscopy performance in Sweden. These differences do not seem to be explained by patient characteristics.

The prediction of colorectal cancer using anthropometric measures: A Swedish population-based cohort study with 22 years of follow-up.

Background: Obesity is a risk factor for colorectal cancer (CRC). Objective: The objective of this article is to investigate whether anthropometric measures reflecting visceral obesity are better predictors of CRC than body mass index (BMI). Methods: Data were analysed from the Malmö Diet and Cancer study in Sweden, comprising 16,669 women and 10,805 men (median age 56.6 and 59.1 years) followed for a median 21.5 years. Diagnoses of CRC were identified using Swedish national registers. Cox regression was used to test the associations of BMI, waist circumference (WC), waist-hip ratio, waist-to-height ratio, waist-to-hip-to-height ratio, A Body Shape Index (ABSI) and percentage body fat with the development of CRC adjusted for age, alcohol consumption, smoking, education and physical activity in men and women. Results: None of the measures were significantly associated with an increased risk for CRC in women. WC was the strongest predictor of colon cancer (CC) in men and the only measure that was independent of BMI. ABSI was the only measure significantly associated with the risk of rectal cancer in men. Conclusions: Visceral obesity, best expressed as WC, is a risk factor for CC in men but a poor predictive marker for CRC in women.

Predicting Outcome in Colonoscopic High-risk Surveillance.

AIM: Surveillance with colonoscopy in risk groups for colorectal cancer needs to be based on an adequate selection of individuals to examine and a well-devised timing. To stratify the risk of finding neoplasia at colonoscopy, a cohort with increased familial risk of colorectal cancer was studied. PATIENTS AND METHODS: Based on family history, 1,203 individuals with at least two-fold increased risk of colorectal cancer were offered regular colonoscopies. The impact of different variables in the family history was assessed by logistic regression for the prevalence of adenoma and advanced adenoma. Findings at first colonoscopy were assessed regarding the association with risk of future lesions. RESULTS: The prevalence of advanced lesions, when controlling for age, was associated with the number of first-degree relatives with colorectal cancer, with an age below 50 years for the youngest family member with colorectal cancer, but not with gender. Family history had a low impact on the prevalence of simple adenoma. The risk of future advanced lesions was only associated with the prevalence of advanced lesions at the screening colonoscopy, whereas a finding of subsequent adenoma was associated with advanced lesions, adenomas and hyperplastic polyps. CONCLUSION: Adenomas and advanced lesions were not associated with the same risk factors. In the present study, the most important risk factors for advanced lesions, including cancer, were the number of first-degree relatives and a young family member with colorectal cancer. Findings of simple adenomas and hyperplastic polyps did not seem to be associated with subsequent advanced lesions.