Microscopic colitis found together with celiac disease in a female population is associated with one episode of lymphocytic colitis.

BACKGROUND: Microscopic colitis (MC) is considered a chronic disease associated with autoimmune disease, smoking, and drugs. The aim was to examine the association between MC and celiac disease, adjusted for smoking, considering subtypes and clinical course of the disease in a retrospectively collected female cohort. METHODS: Women (n = 240), ≤ 73 years, diagnosed as MC in medical records or pathological registers were invited. One hundred and fifty-eight women accepted to be included. Participants completed a study questionnaire about sociodemographic factors, lifestyle habits, and medical history; the Rome III questionnaire; and the visual analog scale for irritable bowel syndrome (VAS-IBS). Participants were categorized into collagenous colitis (CC) (n = 92) and lymphocytic colitis (LC) (n = 66) or MC with one episode of the disease (n = 70) and refractory MC (n = 88). Presence of IBS-like symptoms were noted. Blood samples were collected and analyzed for anti-transglutaminase antibodies. Differences between groups were calculated and logistic regression was adjusted for smoking habits. RESULTS: MC and celiac disease debuted simultaneously in half of the cases. Celiac disease was most prevalent in LC (12.1% vs. 3.3%; p = 0.05) and MC with one episode (12.9% vs. 2.3%; p = 0.01). Anti-transglutaminase antibodies were found in one patient with one episode of MC. Corticosteroid use was most often found in CC (37.0% vs. 21.2%; p = 0.037) and refractory MC (38.6% vs. 20.0%; p = 0.015). Past smokers were most prevalent in patients with one episode of MC (54.3 vs. 29.5%; p = 0.007). Current smoking was the smoking habit with highest prevalence of IBS-like symptoms. When adjusted for smoking habits, celiac disease was associated with LC (OR: 4.222; 95% CI: 1.020-17.469; p = 0.047) and tended to be inversely associated with refractory MC (OR: 0.210; 95% CI: 0.042-1.506; p = 0.058). CONCLUSION: Celiac disease is most common in patients with one episode of LC. The question remains whether LC in combination with celiac disease should be classified as celiac disease or two different entities.

Regional differences in the incidence of lymphocytic and collagenous colitis over time.

BACKGROUND: In microscopic colitis (MC), the incidence has increased over the last decades. The aim of the present study was to determine the incidence of lymphocytic (LC) and collagenous colitis (CC) in the county Skåne (Scania), southern Sweden, during the period 2010-20 with focus both on the temporal and spatial variations. METHODS: The MC diagnosis was retrieved from the biopsy registries at the Departments of Pathology. Established diagnostic criteria (increased lymphocyte count, inflammation in lamina propria and in CC a collagen band) were used for diagnosis. Age, gender, date for diagnosis and municipality of residence were retrieved for all patients. RESULTS: In total 1985 patients could be identified with a mean age of 62.9 years (SD 15.7) whereof 1415 were women. The incidence for CC was stable with a total age-standardized rate (ASR) per 100 000 person-years of 6.34, (range 4.6-8.1). In LC the ASR was 7.90 (range 1.7-15.2) but increased markedly 2015-20 reaching 15.2 in 2019. Also, the northwest part of the region showed significantly higher ASR:s of LC during the last part of the decade in comparation to the whole region. CONCLUSIONS: The incidence of CC was stable during the period while LC differed substantially in a way that indicates that it most probably must be two different disease entities. In LC, in view of the marked and rapid increase, although no definitive explanation could be found, causative environmental factors could be contemplated, why further studies are indicated.

Type 1 diabetes and microscopic colitis: A nationwide matched case-control study in Sweden.

BACKGROUND AND AIMS: Microscopic colitis (MC) is a colonic inflammatory condition associated with autoimmune dysfunction. Type 1 diabetes (T1D) is a chronic disease induced by autoimmune destruction of pancreatic ß-cells. We aimed to examine the association between T1D and MC. METHODS: A matched case-control study was conducted using the nationwide ESPRESSO cohort as study base. All biopsy-confirmed MC patients born after 1940 were identified and compared to biopsy-free individuals matched from the general population for T1D diagnosis using the Swedish National Patient Register. The T1D-MC association was estimated as odds ratios (ORs) and 95% confidence intervals (CIs) by conditional logistic models, considering differences by sex and MC subtype. Full sibling comparison and adjustment for MC-associated medications were also performed. RESULTS: We identified 352 (3.7%) and 945 (2.0%) T1D diagnoses from 9,600 MC cases and 47,870 matched population controls, respectively, which corresponded to an overall OR of 1.79 (95% CI: 1.56-2.05). The association was stronger for collagenous colitis (OR, 2.15; 95% CI: 1.70-2.71) than lymphocytic colitis (OR, 1.62; 95% CI: 1.37-1.92) and remained statistically significant in full sibling comparison (OR, 1.46; 95%: 1.18-1.81). Medication adjustment attenuated the association to null among females (OR: 1.02; 95% CI: 0.82-1.27) but not among males (OR: 1.45; 95% CI: 1.11-1.90). CONCLUSION: T1D diagnosis was almost 80% more prevalent in MC patients compared to general population. This positive association did not seem to be spurious due to residual confounding shared by full siblings but may relate to consumption of medications associated with MC onset.

Celiac disease and risk of microscopic colitis: A nationwide population-based matched cohort study.

BACKGROUND: An association has been reported between celiac disease (CD) and microscopic colitis (MC). However, large, population-based cohort studies are rare. OBJECTIVE: To systematically examine the association between CD and MC in a large, nationwide cohort. METHODS: We conducted a nationwide population-based matched cohort study in Sweden of 45,138 patients with biopsy-verified CD (diagnosed in 1990-2016), 223,149 reference individuals, and 51,449 siblings of CD patients. Data on CD and MC were obtained from all (n = 28) pathology departments in Sweden. Adjusted hazard ratios (aHRs) were calculated using Cox regression. RESULTS: During follow-up, 452 CD patients and 197 reference individuals received an MC diagnosis (86.1 vs. 7.5 per 100,000 person-years). This difference corresponded to an aHR of 11.6 (95% confidence interval [CI] = 9.8-13.8) or eight extra MC cases in 1000 CD patients followed up for 10 years. Although the risk of MC was highest during the first year of follow-up (aHR 35.2; 95% CI = 20.1-61.6), it remained elevated even after 10 years (aHR 8.1; 95% CI = 6.0-10.9). Examining MC subtypes lymphocytic colitis (LC) and collagenous colitis (CC) separately, the aHR was 12.4 (95% CI = 10.0-15.3) for LC and 10.2 (95% CI = 7.7-13.6) for CC. MC was also more common before CD (adjusted odds ratio [aOR] = 52.7; 95% CI = 31.4-88.4). Compared to siblings, risk estimates decreased but remained elevated (CD and later MC: HR = 6.2; CD and earlier MC: aOR = 7.9). CONCLUSION: Our study demonstrated a very strong association of MC with CD with an increased risk of future and previous MC in CD patients. The magnitude of the associations underscores the need to consider the concomitance of these diagnoses in cases in which gastrointestinal symptoms persist or recur despite a gluten-free diet or conventional MC treatment. The comparatively lower risk estimates in sibling comparisons suggest that shared genetic and early environmental factors may contribute to the association between CD and MC.

Frequency And Risk Factors Of Microscopic Colitis As A Cause Of Chronic Watery Diarrhoea.

BACKGROUND: Microscopic colitis (MC) is one of the most underdiagnosed conditions leading to chronic watery diarrhoea in patients worldwide. This is the first study of this kind in Pakistan and we aimed to calculate the frequency as well as study the risk factors behind the disease. METHODS: This was a prospective cross-sectional study in a tertiary care hospital in Pakistan. A total of 58 participants with chronic watery diarrhoea who had normal colonoscopy were recruited for the study and biopsies were obtained for diagnosing MC. RESULTS: 2 participants out of 58 (3.4%) had biopsy proven microscopic colitis; one patient had a lymphocytic colitis variant and the other had a collagenous colitis variant. The average score based on the MC scoring system was 7.53 in the entire study group. The patient with lymphocytic colitis had a score of 06 while the patient with collagenous colitis had a score of 8. CONCLUSIONS: The frequency of microscopic colitis was found to be 3.4% of all cases of chronic watery diarrhoea. A link between MC and autoimmune diseases was also observed. However, we had a limited sample size and encouraged future studies to employ a larger sample size to get a multifaceted look at the disease process.

Microscopic colitis: Etiopathology, diagnosis, and rational management.

Microscopic colitis is an inflammatory bowel disease divided into two subtypes: collagenous colitis and lymphocytic colitis. With an increasing incidence of microscopic colitis exceeding those of ulcerative and Crohn's disease among elderly people in some countries, microscopic colitis is a debilitating life experience. Therefore, physicians should be familiar with its clinical features and management strategies because the disease deserves the same attention as the classical inflammatory bowel diseases. Here, state-of-the-art knowledge of microscopic colitis is provided from a global perspective with reference to etiopathology and how to establish the diagnosis with the overall aim to create awareness and improve rational management in clinical practice. The immune system and a dysregulated immune response seem to play a key role combined with risk factors (e.g. cigarette smoking) in genetically predisposed individuals. The symptoms are characterized by recurrent or chronic nonbloody, watery diarrhea, urgency, weight loss, and a female preponderance. As biomarkers are absent, the diagnosis relies on colonoscopy with a histological assessment of biopsy specimens from all parts of the colon. Although the disease is not associated with a risk of colorectal cancer, a recent nationwide, population-based cohort study found an increased risk of lymphoma and lung cancer. Budesonide is the first-line therapy for management, whereas immunomodulatory drugs (including biologics) and drugs with antidiarrheal properties may be indicated in those failing, dependent, or intolerant to budesonide. In microscopic colitis induced by checkpoint inhibitors, a drug class used increasingly for a wide range of malignancies, a more aggressive therapeutic approach with biologics introduced early seems reasonable. However, particular attention needs to be drawn to the existence of incomplete forms of microscopic colitis with the risk of being overlooked in routine clinical settings.

Microscopic colitis in Northern Ireland: an updated clinicopathological audit and assessment of compliance with European guidelines.

AIM: We previously reported the first population-based study of the epidemiology of microscopic colitis in Northern Ireland. The aim of the current study is to provide updated data on incidence, diagnostic methods and clinicopathological associations, following dissemination of the previous report. A further aim was to compare the findings against relevant recommendations from the 2020 European guidelines. METHOD: Study cases were identified via the Belfast Health and Social Care Trust pathology laboratory system for new cases of collagenous colitis or lymphocytic colitis diagnosed from 2017 to 2020 inclusive. Demographic and clinical information was collated from electronic healthcare records. RESULTS: Two hundred and seventeen new diagnoses of microscopic colitis were made between 2017 and 2020, comprising 89 (41%) collagenous colitis and 128 (59%) lymphocytic colitis. The overall incidence of microscopic colitis, expressed per 100,000 adult population, ranged from 7.6 to 11.5 (5.9 to 9.0 per 100,000 total population). The 2019 peak of 11.5 cases per 100,000 adult population represents a 71.6% increase in incidence compared with the mean incidence of 6.7 per 100,000 adult population from previous data for 2008-2016. There has also been a significant increase in number of cases diagnosed on separate sampling from the right and left colon (85% in 2019-2020 compared with 30% in 2008-2016; p < 0.001). Overall compliance with coeliac serology testing has improved, with 89% tested in 2017-2018 compared with 75% in 2008-2016. CONCLUSION: Clinicopathological communication has contributed to an increased incidence of microscopic colitis in Northern Ireland through better endoscopic diagnostic sampling and pathology coding practices. Coeliac serology testing has also improved, although continued clinical awareness is required of the need for coeliac serology testing in all patients diagnosed with microscopic colitis.

Temporal changes in the histology of microscopic colitis.

BACKGROUND: In a subgroup of patients with microscopic colitis [MC], its histopathology changed from lymphocytic [LC] to collagenous colitis [CC] and vice versa. Previous studies have also observed histopathological transitions between MC and inflammatory bowel disease [IBD]. AIMS: The aim of the present study was to analyse the prevalence of such transitions in a large population of MC patients. METHODS: The Inform Diagnostics database is an electronic repository of histopathology records of patients distributed throughout the USA. In a cross-sectional study, we analysed the prevalence of changes in MC histology. Each prevalence was expressed as the rate per 100 MC patients with its 95% Poisson confidence interval. RESULTS: In a total population of 29 307 MC patients, our cross-sectional study focused on a subgroup of 4363 patients who underwent two or more consecutive colonoscopies between December 2008 and March 2020. Overall, 1.6% [95% CI 1.2-2.0%] of patients changed their MC phenotype from LC to CC, and 0.5% [0.3-0.7%] from CC to LC. Of 4363 MC patients, 414 [9.5%] were also diagnosed with IBD. In 2.9% [2.4-3.5%], MC and IBD were diagnosed as synchronous mucosal lesions. In 2.1% [1.7-2.6%], MC changed to IBD, and in 4.5% [3.9-5.2%] IBD changed to MC. CONCLUSIONS: The analysis confirmed the synchronous occurrence of MC and IBD and transitions between the two diagnoses. In patients who fail therapy for either one of the two diseases, the gastroenterologist should search for changes in the underlying phenotype as a possible explanation.

The Epidemiology of Microscopic Colitis in Olmsted County, Minnesota: Population-Based Study From 2011 to 2019.

BACKGROUND & AIMS: Epidemiologic studies from Europe and North America have reported an increasing incidence of microscopic colitis (MC) in the late 20th century, followed by a plateau. This population-based study assessed recent incidence trends and the overall prevalence of MC over the past decade. METHODS: Residents of Olmsted County, MN, diagnosed with collagenous colitis (CC) or lymphocytic colitis (LC) between January 1, 2011, and December 31, 2019 were identified using the Rochester Epidemiology Project. Clinical variables were abstracted by chart review. Incidence rates were age- and sex-adjusted to the 2010 US population. Associations between incidence and age, sex, and calendar periods were evaluated using Poisson regression analyses. RESULTS: A total of 268 incident cases of MC were identified with a median age at diagnosis of 64 years (range, 19-90 y); 207 (77%) were women. The age- and sex-adjusted incidence of MC was 25.8 (95% CI, 22.7-28.9) cases per 100,000 person-years. The incidence of LC was 15.8 (95% CI, 13.4-18.2) and CC was 9.9 (95% CI, 8.1-11.9) per 100,000 person-years. A higher MC incidence was associated with increasing age and female sex (P < .01). There was no significant trend in age- and sex-adjusted incidence rate over the study period (P = .92). On December 31, 2019, the prevalence of MC, LC, and CC (including cases diagnosed before 2011) was 246.2, 146.1, and 100.1 per 100,000 persons, respectively. CONCLUSIONS: The incidence of MC and its subtypes was stable between 2011 and 2019, but its prevalence was higher than in previous periods. The incidence of MC continues to be associated with increasing age and female sex.

Microscopic colitis: controversies in clinical symptoms and autoimmune comorbidities.

BACKGROUND: Microscopic colitides are chronic immune-inflammatory bowel diseases. The typical presentation is chronic, watery diarrhoea. Inflammation mostly cannot be visualized via macroscopic inspection. The diagnosis thus requires histologic sampling. The clinical picture can vary. New investigations can prove valuable in setting up recommendations. PATIENTS: A total of 103 patients with microscopic colitis (MC) [28 lymphocytic colitis (LC) 27.2%, 75 collagenous colitis (CC) 72.8%] in the Clinical Centre of the University of Debrecen (tertiary care centre) were included, diagnosed between 1993 and 2020. We aimed for a retrospective analysis characterizing Hungarian MC patients. We sought to compare two subgroups of patients (with either LC or CC). Our investigation focussed on dominant alteration of stool habits, autoimmune and allergic comorbidities. Autoimmune diseases were diagnosed in 39% (40) of the patients, allergic diseases in 26.2% (27) of patients and 22.2% of tested patients had alimentary hypersensitivity to certain foods (18 cases out of 81 tested). RESULTS: Age of diagnosis was younger in LC (44.5 years, SD: 5.3 vs. 51.9 years, SD: 12.8, difference= 7.4 years p = .0151). Autoimmune diseases were equally frequent in the two groups (LC: 10 patients 36%, CC: 30 patients, 40%, difference: 4%, p = .7124). Food-linked hypersensitivities were more common in CC (LC: 1 patient, CC: 17 patients). Difference in allergic diseases (asthma, rhinitis, urticaria) did not differ between groups (LC: 6 patients, 21%; CC: 21 patients, 28%, difference: 7% p = .4739). One-third of the patients did not complain about chronic diarrhoea. These patients had chronic constipation as the main symptom (34 patients, 33%). CONCLUSION: Pre-existing autoimmune and allergic diseases were common in patients with MC. Chronic watery diarrhoea is not experienced in many cases. The absence of certain symptoms should not be used to rule out the condition.

Gastrointestinal Infection and Risk of Microscopic Colitis: A Nationwide Case-Control Study in Sweden.

BACKGROUND AND AIMS: Gastrointestinal infections have been linked to changes in the composition and function of gut microbiome and development of inflammatory bowel diseases. We therefore sought to examine the relationship between gastroenteritis and risk of microscopic colitis (MC). METHODS: We conducted a case-control study of all adult patients with MC diagnosed between 1990 and 2016 in Sweden matched to up to 5 general population controls according to age, sex, calendar year, and county. Cases of MC were identified using Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, a cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. We used logistic regression modeling to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: Through December of 2016, we matched 13,468 MC cases to 64,479 controls. The prevalence of previous diagnosed gastrointestinal infection was 7.5% among patients with MC, which was significantly higher than in controls (3.0%, Pcomparison < .001). After adjustment, gastroenteritis was associated with an increased risk of MC (aOR 2.63; 95% CI 2.42-2.85). Among specific pathogens, Clostridioides difficile (aOR 4.39; 95% CI 3.42-5.63), Norovirus (aOR 2.87; 95% CI 1.66-4.87), and Escherichia species (aOR 3.82; 95% CI 1.22-11.58), but not Salmonella species, were associated with an increased risk of MC. The association between gastrointestinal infections and risk of MC was stronger for collagenous subtype (aOR 3.23; 95% CI 2.81-3.70) as compared with lymphocytic colitis (aOR 2.51; 95% CI 2.28-2.76; Pheterogeneity = .005). The associations remained significant after adjustment for immune-mediated conditions and polypharmacy and when compared with unaffected siblings. CONCLUSION: In a nationwide study, we found that gastrointestinal infection, particularly Clostridioides difficile, is associated with an increased risk of subsequent MC. This study was approved by the Regional Ethics Committee, Stockholm, Sweden (Protocol no. 2014/1287-31/4).

Epidemiological and clinical characteristics, and response to treatment in 113 patients with microscopic colitis. / Características epidemiológicas, clínicas y respuesta al tratamiento en 113 pacientes con colitis microscópica.

OBJECTIVE: To study the epidemiological and clinical characteristics, and response to treatment in patients with microscopic colitis. PATIENTS AND METHOD: Epidemiological, clinical, blood test and endoscopic data were retrospectively collected from 113 patients with microscopic colitis. Response to treatment was analyzed in 104 of them. Efficacy and relapse after treatment with budesonide were assessed using survival curves (Kaplan-Meier). RESULTS: 78% of the patients were women, with a mean age of 65 ± 16 years. In smokers, the mean age was 10 years younger. 48% of them had some concomitant autoimmune disease; 60% suffered a single outbreak of the disease. The clinical presentation was similar in both subtypes, although patients with collagenous colitis had a chronic course more frequently (48% vs. 29%, p = 0.047). The remission rate with budesonide was 93% (95% CI 82-98). The cumulative incidence of relapse, after a median follow-up of 21 months, was 39% (95% CI 26-54%): 19% at one year, 32% at two years, and 46% at three years of follow-up. There were no differences in clinical response to budesonide based on smoking habit or microscopic colitis subtype. CONCLUSIONS: Microscopic colitis is more frequent in elderly women. Smoking was associated with earlier onset of the disease, although it did not influence the clinical course or response to treatment. The majority (> 90%) of patients treated with budesonide achieved remission, although nearly half subsequently relapsed.

Microscopic colitis and its associations with complications observed in classic inflammatory bowel disease: a systematic review.

Objectives: Crohn's disease and ulcerative colitis are associated with an increased risk to develop anemia, cutaneous diseases, liver diseases, malignancy, osteoporosis, rheumatic diseases, thromboembolism and uveitis. The association between these diseases and microscopic colitis (MC) is not known. The aim of the present systematic review was to examine associations between MC and diseases observed in association with Crohn's disease and ulcerative colitis.Material and methods: According to the review protocol, original articles which described the prevalence of abovementioned diseases in relation to MC, were searched for in PubMed, Embase and Web of Science.Results: After exclusion of duplicates, 928 articles remained. Based on relevancy of their title, abstract or type of article, 16 articles were ordered in full text and after assessment, nine articles could be included in the review. A second research strategy with individual diseases rendered further two articles. Seven articles covered malignancy/neoplasia, where four showed no association with malignancy and three a reduced association compared with controls. Four articles covering rheumatic diseases showed an association between these diseases and MC. One study showed an association between MC and osteoporosis, whereas one did not. One study showed an association between MC and cutaneous diseases, whereas anemia, eye diseases and thromboembolism showed no associations.Conclusions: Due to short follow-up time in small studies, with selection bias due to exclusion of former or prevalent malignancy in an older population, no conclusions can be drawn concerning the true association between MC and malignancy. Rheumatic diseases seem to be associated with MC.

A nationwide cohort study of the incidence of microscopic colitis in Sweden.

BACKGROUND: Epidemiological studies of microscopic colitis have shown varying but increasing incidence rates. AIM: To assess the incidence of microscopic colitis in Sweden. METHODS: Nationwide cohort study performed in 1995-2015 based on biopsy reports. Age-specific and age-standardised incidence rates were calculated. RESULTS: We identified 13 844 patients with an incident diagnosis of microscopic colitis. Lymphocytic colitis (n = 9238) constituted 67% and collagenous colitis (n = 4606) 33% of microscopic colitis. The mean age at time of diagnosis of microscopic colitis was 60.2 years (58.6 for lymphocytic colitis, 63.3 for collagenous colitis). The lifetime risk of developing microscopic colitis was 0.87% in women (95% confidence interval, CI: 0.85-0.88) and 0.35% in men (95% CI: 0.34-0.36). From 2006, the overall incidence of microscopic colitis was approximately 10.5 cases per 100 000 person-years (95% CI: 9.8-11.3) with higher rates in women (72% of cases, incidence rate ratio = 2.4 (95% CI: 2.3-2.5) and the elderly with increasing rates up to 75-79 years. From 2006-2015, there was a significant increase of 1% per year (P = 0.02) in the overall microscopic colitis incidence rate in women; the estimated annual percent change was similar, although not statistically significant, in men (P = 0.15). CONCLUSIONS: In Sweden, the incidence of microscopic colitis is still increasing in women, although the rate appears to be stabilising. The incidence is particularly high in women and the elderly up to age 75-79 years. Finally, across a lifetime, 1 in 115 females and 1 in 286 males are expected to be diagnosed with microscopic colitis and thus posing a considerable disease burden.

Retrospective study recommends endoscopy when diagnosing lymphocytic colitis or eosinophilic gastrointestinal disorder in children with abdominal pain.

AIM: This study assessed the prevalence, clinical presentation and outcome of lymphocytic colitis (LC) and eosinophilic gastrointestinal disease (EGID) in children with severe, recurrent abdominal pain (RAP), by describing the predominant symptoms, diagnostic approaches and treatment options. METHODS: We performed a retrospective follow-up study at a Danish regional hospital by reviewing the histology reports of the children who had undergone gastrointestinal endoscopy for RAP. Data were retrieved from the medical records of those who met the diagnostic criteria for LC and, or, EGID from 2011 to 2016. The study population comprised 381 patients who underwent a diagnostic process to clarify RAP. RESULTS: A total of 74 patients (39 females) aged 2-17 years, with severe RAP as the most predominant symptom underwent gastrointestinal endoscopy. This identified 16/74 (21.6%) with LC (n = 6) and, or, EGID (n = 11), which equated to 4.2% with RAP. No biochemical patterns of abnormalities were found. Medical treatment and, or, diet generally induced and maintained clinical remission. CONCLUSION: We found 16 children with LC and, or, EGID. The predominant symptom was severe RAP. All patients had a macroscopically normal mucosa at endoscopy, a specific histopathological feature and no characteristic biochemical findings. Endoscopy should be considered in these cases.

Significant association between the use of different proton pump inhibitors and microscopic colitis: a nationwide Danish case-control study.

BACKGROUND: Microscopic colitis causes chronic watery diarrhoea and has previously been associated with the use of proton pump inhibitors. AIM: To explore the association between proton pump inhibitor use and microscopic colitis, including its dependency on timing, dose and choice of proton pump inhibitor. METHODS: Within a 10-year period, we identified 10 652 patients with a first-time diagnosis of microscopic colitis, including 6254 (59%) with collagenous colitis and 4398 (41%) with lymphocytic colitis. All microscopic colitis cases were histologically confirmed in the Danish Pathology Register. Information on proton pump inhibitor use was obtained from the Danish Prescription Register. In this case-control study, we estimated the adjusted odds ratios (aOR) for the association between proton pump inhibitor use and risk of microscopic colitis using conditional logistic regression while adjusting for potential confounders. RESULTS: We found strong associations between current proton pump inhibitor use and both collagenous colitis (aOR 6.98; 95% CI: 6.45-7.55) and lymphocytic colitis (aOR 3.95; 95% CI: 3.60-4.33). This association was observed with all PPIs. The strongest association was with the current use of lansoprazole for both collagenous colitis (aOR 15.74; 95% CI: 14.12-17.55) and lymphocytic colitis (aOR 6.87; 95% CI: 6.00-7.86). When considering timing, ORs were highest for current use of proton pump inhibitor and lower for recent or past exposure. No clear dose-response pattern was observed. CONCLUSIONS: We found a strong association between microscopic colitis and ongoing use of proton pump inhibitors, especially lansoprazole.

Microscopic colitis: a population-based case series over a 9-year period in Northern Ireland.

AIM: We report clinicopathological experience of microscopic colitis (MC) in a population-based case series in Northern Ireland over a 9-year period. METHOD: The pathology laboratory information system within a large teaching centre serving two healthcare trusts was interrogated for cases coded between 2008 and 2016 as collagenous colitis (CC) or lymphocytic colitis (LC). Demographic, clinical and follow-up information was collected from healthcare records. RESULTS: A total of 326 new diagnoses of MC were identified, an average annual incidence of 6.7 per 100 000 population. The average annual incidence of CC and LC was 5.0 and 1.7 per 100 000 population, respectively. For coding reasons it is likely that LC data are incomplete. Of 191 cases diagnosed by specialist gastrointestinal pathologists, 141 patients had CC and 50 patients had LC. Both CC and LC predominantly involved women aged 60-79. Some 15% demonstrated endoscopic abnormalities. Endoscopic sampling protocols varied widely: 30% of individuals with CC and 32% of those with LC had the right and left colon sampled separately, with histology concordant in 95% of cases. Of the 191 cases, only one case (of LC) was refractory to treatment; the rest exhibited a clinical response. Only 35 patients had follow-up endoscopy and biopsies, and three of each diagnosis showed persistent disease on histology. CONCLUSION: Overall, CC and LC are benign conditions with similar demographics, clinical associations, management and outcomes. Separate sampling of the right and left colon is advised at colonoscopy if this diagnosis is being considered, but left colonic sampling, which can be performed at flexible sigmoidoscopy, will diagnose the vast majority of cases.

Microscopic colitis in patients with ulcerative colitis or Crohn's disease: a retrospective observational study and review of the literature.

OBJECTIVES: Onset of microscopic colitis (MC) in patients with ulcerative colitis (UC) or Crohn's disease (CD), or vice versa, has been reported occasionally but the subject is not well described. We therefore report a retrospective observational study of such patients and review the literature. METHODS: Forty-six Swedish gastroenterology clinics were contacted about patients with diagnoses of both inflammatory bowel disease (IBD) and MC. Publications were searched on PubMed. RESULTS: We identified 31 patients with onset of MC after a median (range) of 20 (2-52) years after diagnosis of IBD, or vice versa; 21 UC patients developed collagenous colitis (CC) (n = 16) or lymphocytic colitis (LC) (n = 5); nine CD patients developed CC (n = 5) or LC (n = 4); one CC patient developed CD. Of the 21 UC patients, 18 had extensive disease, whereas no consistent phenotype occurred in CD. Literature review revealed 27 comprehensive case reports of patients with diagnoses of both IBD and MC. Thirteen MC patients developed IBD, of which four required colectomy. Fourteen IBD patients later developed MC. There were incomplete clinical data in 115 additional reported patients. CONCLUSIONS: Altogether 173 patients with occurrence of both IBD and MC were found. The most common finding in our patients was onset of CC in a patient with UC. Although these are likely random associations of two different disorders, MC should be considered in the patient with UC or CD if there is onset of chronic watery diarrhoea without endoscopic relapse of IBD.

Smoking is Associated with an Increased Risk of Microscopic Colitis: Results From Two Large Prospective Cohort Studies of US Women.

BACKGROUND: Long-term data on the influence of smoking on risk of microscopic colitis are limited. We therefore sought to examine and characterize the association between smoking and risk of incident microscopic colitis in two large prospective cohorts of women. METHODS: We conducted a prospective study of 231015 women enrolled in the Nurses' Health Study [NHS] and NHSII. Information regarding smoking, other lifestyle factors and medications were collected biennially from 1976 to 2012 in NHS and from 1989 to 2013 in NHSII. Incident cases of microscopic colitis were confirmed through physician medical record review. We used Cox proportional hazards modelling to examine the association between smoking and risk of microscopic colitis. RESULTS: We documented 166 incident cases of microscopic colitis over 6122779 person-years of follow up. Compared to non-smokers, the multivariable-adjusted hazard ratio [HR] for microscopic colitis was 2.52 (95% confidence interval [CI] 1.59-4.00) amongst current smokers and 1.54 [95% CI 1.09-2.17] amongst past smokers. The risk increased with higher pack-years of smoking [p trend = 0.001] and diminished following smoking cessation [p trend = 0.017]. Current smoking appeared to be more strongly associated with risk of collagenous colitis [HR 3.68; 95% CI 1.94-6.97] than lymphocytic colitis [HR 1.71; 95% CI 0.83-3.53]. CONCLUSION: In two large prospective cohort studies, we observed an association between current smoking and risk of microscopic colitis. Risk of microscopic colitis appeared to increase with higher pack-years and diminish following smoking cessation. Future studies focused on characterizing the biological mechanisms underlying these associations are warranted.