The association between the intake of specific dietary components and lifestyle factors and microscopic colitis

A Literature Review of Microscopic Colitis

Although the clinical importance of microscopic colitis (MC) is highly increasing, however, the disease is still mysterious due to several challenges. Recent MC data depend mainly on doubts and uncertainties leading to misclassification. This review discussed the current knowledge gaps about MC and various controversies regarding its subtypes, pathogenesis, and management. The diagnosis of MC is based mainly on histology and immunohistopathology which can discriminate two subtypes. However, transitional forms are often associated with misclassification. The site and number of the colon biopsies have been agreed upon as at least three from each side of the colon (right and left) with a total of six. There is no credible, clear explanation for the increased incidence. The etiopathogenesis is possibly multifactorial with a high impact on the immunological background. It is proposed that MC would be the initiative of irritable bowel disease, which needs further data clarification. Although budesonide is an effective treatment in most cases, budesonide-refractory MC represents a significant clinical challenge. Therefore, immunomodulators and biologics are now well-thought to be the second-line choice for treatment.

Microscopic Colitis and Risk of Incident Acute Pancreatitis: A Nationwide Population-Based Matched Cohort Study

INTRODUCTION

Several gastrointestinal diseases have been linked to acute pancreatitis, but the risk of acute pancreatitis in microscopic colitis (MC) has not been studied.

METHODS

We conducted a nationwide, population-based, matched cohort study in Sweden of 12,140 patients with biopsy-verified MC (diagnosed in 2003-2017), 57,806 matched reference individuals, and 12,781 siblings without MC with a follow-up until 2021. Data on MC were obtained from all of Sweden's regional pathology registers (n = 28) through the ESPRESSO cohort. Data on acute pancreatitis were collected from the National Patient Register. Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) were calculated using Cox regression.

RESULTS

During a mean follow-up of 9.9 years (SD = 4.3), 146 patients with MC and 437 reference individuals were diagnosed with acute pancreatitis (127.8 vs 80.1 per 100,000 person-years), corresponding to an aHR of 1.57 (95% CI = 1.30-1.90). Moreover, we found a positive association between MC and acute nongallstone-related pancreatitis (aHR 1.99 [95% CI = 1.57-2.51]), but not with acute gallstone-related pancreatitis (aHR 1.08 [95% CI = 0.78-1.49]). Comparing patients with MC with their unaffected siblings yielded an aHR of 1.28 (95% CI = 0.92-1.78). The risk of acute pancreatitis remained elevated also for patients with MC with a follow-up exceeding 10 years (aHR 1.75 [95% CI = 1.14-2.67]).

DISCUSSION

This nationwide study of more than 12,000 patients with MC demonstrated an increased risk of acute pancreatitis after MC. Hence, clinicians should have a low threshold for the evaluation of acute pancreatitis in patients with MC. In addition, these patients should receive advice and care aimed at reducing the risk of acute pancreatitis.

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.

Dietary Calcium and Risk of Microscopic Colitis

BACKGROUND

Microscopic colitis (MC) is an increasingly common cause of watery diarrhea particularly in older individuals. The role of diet in MC has received little study.

METHODS

We conducted a case-control study at a single institution enrolling patients referred for elective outpatient colonoscopy for diarrhea. Patients were classified as cases with MC or non-MC controls after a review of colon biopsies by 1 research pathologist. Study subjects were interviewed by a trained telephone interviewer using a validated food frequency questionnaire. Adherent microbes were evaluated from colonic biopsies using 16s rRNA sequencing.

RESULTS

The study population included 106 cases with MC and 215 controls. Compared with controls, the cases were older, better educated, and more likely to be female. Cases with MC had lower body mass index and were more likely to have lost weight. Subjects in the highest quartile of dietary calcium intake had a lower risk of MC compared with those in the lowest quartile (adjusted odds ratio 0.22, 95% confidence interval 0.07-0.76). The findings were not explained by dairy intake, body mass index, or weight loss. We found that dietary calcium intake had significant associations with the abundance of Actinobacteria and Coriobacteriales in the microbial community of colonic biopsies.

DISCUSSION

Compared with patients with diarrhea, cases with MC had a lower intake of dietary calcium. Diet can be associated with alterations in the gut microbiota and with luminal factors that could affect the risk of MC.

Reduced Intake of Dietary Tryptophan Improves Beneficial Action of Budesonide in Patients with Lymphocytic Colitis and Mood Disorders

Lymphocytic colitis (LC) is a gastrointestinal (GI) tract disease with poorly known pathogenesis, but some environmental and lifestyle factors, including certain dietary components, may play a role. Tryptophan is an essential amino acid, which plays important structural and functional roles as a component of many proteins. It is important in the development and maintenance of the body, in which it is metabolized in two main pathways: kynurenine (KYN) and serotonin. In this work, we explored the effect of reducing of TRP in the diet of patients with LC with mood disorders. We enrolled 40 LC patients who had a normal diet, 40 LC patients with the 8-week diet with TRP content reduced by 25% and 40 controls. All LC patients received budesonide at 9 mg per day, and the severity of their GI symptoms was evaluated by the Gastrointestinal Symptoms Rating Scale. Mood disorders were evaluated by the Hamilton Anxiety Rating Scale (HAM-A) and the Hamilton Depression Rating Scale (HAM-D). The concentration of TRP and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QA), in urine were determined. Budesonide improved the GI and mental states of LC patients, and the diet with reduced TRP content further amended these symptoms. Dietary intervention decreased the concentration of 5-HIAA by about 50% (3.4 vs. 6.3) and QA by about 45% (3.97 vs. 7.20). These changes were correlated with a significant improvement in the profitable action of budesonide on gastrointestinal and mental health of LC patients as they displayed significantly lower GSRS, HAM-A and HAM-B scores after than before the intervention—10.5 vs. 32, 11.0 vs. 21 and 12 vs. 18, respectively. In conclusion, a reduction in TRP intake in diet may improve GI and mental symptoms in LC patients treated with budesonide and these changes may be mediated by the products of TRP metabolism.

Rheumatologic Associations of Microscopic Colitis: A Narrative Review

Extra-intestinal manifestations are frequent complications of the classical inflammatory bowel diseases, Crohn's disease and ulcerative colitis. However, in addition to the classical diseases, there is a spectrum of conditions, often termed "microscopic colitis", in which extra-intestinal manifestations are less well described. Our objective was to review the literature regarding the extra-intestinal manifestations complicating microscopic colitis and describe the association with systemic autoimmune rheumatic diseases. A comprehensive search and review of peer-reviewed English-language and international journals and reports was completed based on key terms, including "microscopic colitis", "lymphocytic colitis", "collagenous colitis", "inflammatory bowel disease", "extraintestinal manifestations", and the specific disease associations utilizing the PubMed Central database and MEDLINE. A broad spectrum of rheumatologic manifestations has been reported in patients with microscopic colitis. The identification of rheumatoid arthritis and limited scleroderma as co-morbidities with microscopic colitis was noteworthy. Inflammatory arthropathy was frequently seen in microscopic colitis, usually preceding or occurring in conjunction with the onset of gastrointestinal symptoms. A variety of presentations of associated arthritis were reported: migratory, symmetric or asymmetric, peripheral or axial, oligoarticular or polyarticular, erosive or non-erosive. There was a high incidence of autoantibodies in these patients, supporting a potential autoimmune association. On the basis of these anecdotal reports, we would suggest development of a clinical registry to help define the incidence of extra-intestinal manifestations and systemic autoimmune rheumatic diseases among microscopic colitis patients to help elucidate shared predispositions, pathogenic mechanisms and therapeutic opportunities.

Lack of autoantibodies against collagen and related proteins in collagenous colitis

Introduction

Collagenous colitis (CC) is a common cause of chronic diarrhea and is characterized by a subepithelial thickened collagen layer in the colonic mucosa.

It shares many of the characteristics found in autoimmune diseases, but no autoantibodies have been identified. In CC, an imbalance in collagen turnover is evident. The purpose of the present study was to investigate whether any collagen-associated autoantibodies or other antibodies such as TPO and ASCA were present, and if levels of total IgE were increased.

Methods

Sera from women with active CC were analysed with ELISA for detection of autoantibodies against collagen type III and IV (Col III and IV), matrix metalloproteinase-9 (MMP-9), tissue inhibitors of metalloproteinase-1 (TIMP-1) and tenascin-C (TNC). Sera were also analysed for TPO, ASCA and total IgE. Healthy female blood donors served as controls. The cut-off value in the control group was defined as relative units > 97.5th percentile.

Results

Sixty-six women were included (mean age 60 years; range 31–74, mean disease duration 6 years; range 1–22). No autoantibody was significantly overexpressed in the CC population compared to controls. The mean disease duration was lower (p = 0.03) in the subjects who expressed collagen-associated autoantibodies (3.7 years; range 1–14), compared to those who did not (6.4 years; range 1–22). Treatment with budesonide was not associated with any of these autoantibodies.

Conclusion

No increased presence of the investigated antibodies could be found in the present study of CC. Neither could antibodies against ASCA or TPO, or elevated levels of IgE, be found. Consequently, no association was found between CC and these proteins, even though this may not be generalizable to other compounds in the collagen layer.

Microscopic Colitis in Denmark: Regional Variations in Risk Factors and Frequency of Endoscopic Procedures

OBJECTIVE

Microscopic colitis [MC], encompassing collagenous colitis [CC] and lymphocytic colitis [LC], is an increasingly prevalent gastrointestinal disease with an unknown aetiology. Previous research has reported significant differences in the incidence of MC within Denmark, with the lowest incidence found in the most populated region [Capital Region of Denmark]. Our aim was to elucidate the causes of these regional differences.

DESIGN

All incident MC patients [n = 14 302] with a recorded diagnosis of CC [n = 8437] or LC [n = 5865] entered in The Danish Pathology Register between 2001 and 2016 were matched to 10 reference individuals [n = 142 481]. Information regarding drug exposure, including proton pump inhibitors [PPIs], selective serotonin reuptake inhibitors [SSRIs], statins, and nonsteroidal anti-inflammatory drugs [NSAIDs], were retrieved from The Danish National Prescription Registry. Information regarding endoscopy rate, smoking-related diseases, and immune-mediated inflammatory diseases were acquired from The Danish National Patient Registry.

RESULTS

Smoking, immune-mediated inflammatory diseases, exposure to PPIs, SSRIs, statins, and NSAIDs were significantly associated with MC in all Danish regions. The association between drug exposure and MC was weakest in the Capital Region of Denmark with an odds ratio of 1.8 (95% confidence interval [CI]: 1.61-2.01). The relative risk of undergoing a colonoscopy with biopsy was significantly increased in sex- and age-matched controls in all regions compared with controls from the Capital Region of Denmark, with the greatest risk found in the Region of Southern Denmark, 1.37 [95% CI: 1.26-1.50].

CONCLUSIONS

The cause of the regional differences in MC incidence in Denmark seems to be multifactorial, including variations in disease awareness and distribution of risk factors.

Obesity is associated with decreased risk of microscopic colitis in women

BACKGROUND

Microscopic colitis is a leading cause of diarrhea in the older adults. There is limited information about risk factors. We hypothesized that obesity would be associated with microscopic colitis.

AIM

To examine the association between obesity and microscopic colitis in men and women undergoing colonoscopy.

METHODS

We conducted a case-control study at the University of North Carolina Hospitals. We identified and enrolled men and women referred for elective, outpatient colonoscopy for chronic diarrhea. We excluded patients with a past diagnosis of Crohn’s disease or ulcerative colitis. A research pathologist reviewed biopsies on every patient and classified them as microscopic colitis cases or non-microscopic colitis controls. Patients provided information on body weight, height and exposure to medications via structured interviews or Internet based forms. The analysis included 110 patients with microscopic colitis (cases) and 252 non-microscopic colitis controls. Multivariable analyses were performed using logistic regression to estimate odds ratios and 95% confidence intervals.

RESULTS

Cases were older and more likely than controls to be white race. Study subjects were well educated, but cases were better educated than controls. Cases with microscopic colitis had lower body mass index than controls and reported more weight loss after the onset of diarrhea. Compared to patients who were normal or under-weight, obese (BMI > 30 kg/m²) patients were substantially less likely to have microscopic colitis after adjusting for age and education, adjusted OR (aOR) 0.35, 95% confidence interval (CI) 0.18-0.66). When stratified by sex, the association was limited to obese women, aOR 0.21, 95%CI: 0.10-0.45. Patients with microscopic colitis were more likely to report weight loss after the onset of diarrhea. After stratifying by weight loss, there remained a strong inverse association between obesity and microscopic colitis, aOR 0.33, 95%CI: 0.10 – 1.11 among the patients who did not lose weight. Ever use of birth control pills was associated with lower risk of microscopic colitis after adjusting for age, education and BMI, aOR 0.38, 95%CI: 0.17-0.84.

CONCLUSION

Compared to controls also seen for diarrhea, microscopic colitis cases were less likely to be obese. Mechanisms are unknown but could involve hormonal effects of obesity or the gut microbiome.

Patients With Microscopic Colitis Have Altered Levels of Inhibitory and Stimulatory Biomarkers in Colon Biopsies and Sera Compared to Non-inflamed Controls

Introduction: Microscopic colitis (MC) is an inflammatory bowel condition with two subtypes, lymphocytic colitis (LC) and collagenous colitis (CC). Unlike patients with ulcerative colitis (UC) and non-inflamed individuals, MC patients have reduced risk of developing colorectal cancer, possibly due to increased immune surveillance in MC patients.

Aim: To examine differences in levels of immunomodulatory molecules, including those involved in immune checkpoint mechanisms, in sera from patients with MC and in colonic biopsies from patients with MC and UC compared with controls.

Methods: Using Luminex, 23 analytes (4-1BB, 4-1BBL, APRIL, BAFF, BTLA, CD27, CD28, CD80, CTLA-4, E-cadherin, Galectin-3, GITR, HVEM, IDO, IL-2Rα, LAG-3, MICA, MICB, PD-1, PD-L1, PD-L2, sCD40L and TIM-3) were studied in serum from patients with active MC (n = 35) and controls (n = 23), and in colonic biopsies from patients with active LC (n = 9), active CC (n = 16) and MC in histological remission (LC n = 6, CC n = 6), active UC (n = 15) and UC in remission (n = 12) and controls (n = 58).

Results: In serum, IDO, PD-1, TIM-3, 4-1BB, CD27, and CD80 were decreased whereas 4-1BBL and IL-2Rα were increased in MC patients compared with controls. In contrast, in biopsies, levels of PD-L2 and 4-1BB were increased in MC and UC patients with active disease. Furthermore, in biopsies from CC and UC but not LC patients with active disease, CTLA-4, PD-1, APRIL, BAFF, and IL-2Rα were increased compared with controls. PD-L1 was increased in CC but not UC or LC patients. CD27 and TIM-3 were decreased in biopsies from MC patients in comparison to controls whereas levels of MICB were decreased in patients with active UC compared with controls.

Conclusions: Compared with non-inflamed controls, levels of soluble and membrane-bound immunomodulatory molecules were systemically and locally altered in MC and UC patients, with most analytes being decreased in serum but enhanced in colonic biopsies. These findings contribute to knowledge about checkpoint molecules and their role as biomarkers in MC and may also contribute to knowledge about possible mechanisms behind the seemingly protective effects of MC against colorectal cancer.

Alcohol Consumption is Associated With An Increased Risk of Microscopic Colitis: Results From 2 Prospective US Cohort Studies

BACKGROUND

No dietary factors have yet been shown to conclusively impact the incidence of microscopic colitis (MC). Here, we sought to examine the relationship between alcohol intake and the risk of MC.

METHODS

We conducted a prospective cohort study of 209,902 participants (age range, 28.5-66.7 years) enrolled in the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII). Validated data on alcohol consumption were collected at baseline in 1986 in the NHS and 1991 in the NHSII and updated every 4 years. Diagnoses of MC were confirmed via review of histopathology data. We used Cox proportional hazards modeling to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

RESULTS

Through 2016 in the NHS and 2017 in the NHSII, we confirmed 352 incident cases of MC over 4,994,324 person-years. Higher alcohol consumption was associated with an increased risk of MC (Ptrend < .001). Compared to non-users, the aHRs of MC were 1.20 (95% CI, 0.86-1.67) for consumers of 0.1-4.9 g/day of alcohol, 1.90 (95% CI, 1.34-2.71) for consumers of 5-14.9 g/day, and 2.31 (95% CI, 1.54-3.46) for consumers of ≥15 g/day. The associations were consistent across the histologic subtypes of collagenous and lymphocytic colitis (Pheterogeneity = .523). When stratified by alcohol type, the risk according to every 2 servings/week appeared to be strongest with consumption of wine (aHR, 1.08; 95% CI, 1.04-1.12) as compared to beer (aHR, 1.01; 95% CI, 0.91-1.12) or liquor (aHR, 1.00; 95% CI, 0.92-1.09).

CONCLUSIONS

Alcohol consumption was associated with an increased risk of MC. Further studies are needed to determine the mechanism underlying these associations, as well as the impact of reducing alcohol intake in patients with MC.

Microscopic colitis

Microscopic colitis (MC) is an inflammatory disease of the large intestine associated with urgent watery diarrhoea. MC may occur in people of all ages, although the disease primarily affects older women. Once believed to be rare, MC is now known to be a common cause of chronic watery diarrhoea in high-income countries, affecting 1 in 115 women and 1 in 286 men during their lifetime in Swedish population-based estimates. An inappropriate immune response to disturbances in the gut microenvironment is implicated in the pathogenesis of MC. Evidence also supports an underlying genetic basis for disease. The diagnosis of MC relies on clinical symptoms and microscopic assessment of colonic biopsy samples. MC is categorized histologically into collagenous colitis, lymphocytic colitis and their incomplete forms. The mainstay of treatment includes the use of budesonide, with or without adjunctive therapies, and withdrawal of offending drugs. Emerging studies suggest a role for biologicals and immunosuppressive therapies for the management of budesonide-refractory or budesonide-dependent disease. MC can have a substantial negative effect on patient quality of life. The outlook for MC includes a better understanding of the immune response, genetics and the microbiome in disease pathogenesis along with progress in disease management through robust clinical trials.

European guidelines on microscopic colitis: United European Gastroenterology and European Microscopic Colitis Group statements and recommendations

INTRODUCTION

Microscopic colitis is a chronic inflammatory bowel disease characterised by normal or almost normal endoscopic appearance of the colon, chronic watery, nonbloody diarrhoea and distinct histological abnormalities, which identify three histological subtypes, the collagenous colitis, the lymphocytic colitis and the incomplete microscopic colitis. With ongoing uncertainties and new developments in the clinical management of microscopic colitis, there is a need for evidence-based guidelines to improve the medical care of patients suffering from this disorder.

METHODS

Guidelines were developed by members from the European Microscopic Colitis Group and United European Gastroenterology in accordance with the Appraisal of Guidelines for Research and Evaluation II instrument. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists, pathologists and basic scientists, and voted upon using the Delphi method.

RESULTS

These guidelines provide information on epidemiology and risk factors of microscopic colitis, as well as evidence-based statements and recommendations on diagnostic criteria and treatment options, including oral budesonide, bile acid binders, immunomodulators and biologics. Recommendations on the clinical management of microscopic colitis are provided based on evidence, expert opinion and best clinical practice.

CONCLUSION

These guidelines may support clinicians worldwide to improve the clinical management of patients with microscopic colitis.

Epidemiological and clinical characteristics, and response to treatment in 113 patients with microscopic colitis

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: pathophysiology and clinical management

Microscopic colitis is a chronic inflammatory disease of the colon that frequently causes chronic watery diarrhoea that might be accompanied by abdominal pain, nocturnal diarrhoea, urgency, and faecal incontinence. These symptoms lead to poor quality of life and increased health-care costs. Diagnosis relies on histological examination of multiple biopsy samples from the colonic mucosa, which often show no or only few abnormalities on endoscopy. Two major histological subtypes can be distinguished-collagenous colitis and lymphocytic colitis-but incomplete and variant forms with fewer characteristic features have been reported. Here we summarise the latest evidence on epidemiology, pathogenesis, and risk factors, and discuss established and novel therapeutic options for clinical remission. Finally, we propose an updated treatment algorithm. Further prospective studies are needed to clarify the natural history of microscopic colitis, supported by validated criteria for the assessment of disease activity.

The association between smoking and both types of microscopic colitis: A systematic review and meta-analysis

BACKGROUND AND STUDY AIMS

It has been suggested that smoking may be associated with microscopic colitis (MC) in some studies; however, there are conflicting results in the current literature with many of these studies having significant limitations. Our study aims to offer a meta-analysis evaluating the association between MC, including both its subtypes, and smoking.

PATIENTS AND METHODS

A systemic review was conducted in PUBMED, Embase, PubMed Central, and ScienceDirect databases from inception through December 2019. Effect estimates from the individual studies were extracted and combined using the random effect, generic inverse variance method of DerSimonian and Laird and a pooled odds ratio (OR) was calculated. Forest plots were generated, and publication bias was assessed for using conventional techniques.

RESULTS

Eight observation studies with a total of 1461 patients with MC were included in this study, 383 of whom were active smokers (26.2%). Current smoking was significantly associated with MC (OR 3.58, 95% CI, 2.51-5.11), lymphocytic colitis (LC) (OR 3.64, 95% CI, 2.46-5.38), and collagenous colitis (CC) (OR 4.43, 95% CI, 2.68-7.32). Gender-specific subgroup analysis showed a significant association with smoking was found for CC in men (OR 4.53, 95% CI, 1.59-12.85), CC in women (OR 3.27, 95% CI, 2.35-4.54), LC in women (OR 2.27, 95% CI, 1.27-4.06) and MC in women (OR 2.93, 95% CI, 2.09-4.10). We found no publication bias as assessed by the funnel plots and Egger's regression asymmetry test.

CONCLUSION

Our meta-analysis found a statistically significant association between smoking and both subtypes of MC.

Cancer Risk in Collagenous Colitis

Data on malignancy in patients with collagenous colitis (CC) is scarce. We aimed to determine the incidence of cancers in patients with CC. In a two-stages, observational study, data on cancers in patients diagnosed with CC during 2000-2015, were collected from two cohorts. The risk was calculated according to the age-standardized rate for the first cohort and according to the standardized incidence ratio for the second cohort. The first cohort comprised 738 patients (394 from Scotland and 344 from Sweden; mean age 71 ± 11 and 66 ± 13 years, respectively). The incidence rates for lung cancer (RR 3.9, p = 0.001), bladder cancer (RR 9.2, p = 0.019), and non-melanoma skin cancer (NMSC) (RR 15, p = 0.001) were increased. As the majority of NMSC cases (15/16) came from Sweden, a second Swedish cohort, comprising 1141 patients (863 women, mean age 65 years, range 20-95 years) was collected. There were 93 cancer cases (besides NMSC). The risk for colon cancer was decreased (SIR 0.23, p= 0.0087). The risk for cutaneous squamous cell carcinoma was instead markedly increased (SIR 3.27, p = 0.001).

Obesity and Weight Gain Since Early Adulthood Are Associated With a Lower Risk of Microscopic Colitis

BACKGROUND & AIMS

Obesity promotes intestinal inflammation and might contribute to the pathogenesis of inflammatory bowel disease. We examined the association between obesity and risk of microscopic colitis in a prospective cohort study.

METHODS

We collected data from 192,101 women enrolled in the Nurses' Health Study (NHS) (from 1986 through 2014) or the NHSII (from 1991 through 2015). Anthropomorphic and lifestyle information were self-reported biennially. Obesity was defined using body mass index (BMI). Microscopic colitis was confirmed by review of medical records. We used Cox proportional hazard models to estimate adjusted hazard ratios (aHRs) and 95% CIs.

RESULTS

Among the participants in the NHS and NHSII, we confirmed 244 cases of microscopic colitis during 4,223,868 person-years of follow-up evaluation. Higher BMI was associated inversely with risk of microscopic colitis (Ptrend < .001). Compared with women with BMIs ranging from 18.5 to 20.9 kg/m², the aHRs were 0.61 (95% CI, 0.41-0.91) for overweight women (BMI, 25-29.9 kg/m²) and 0.50 (95% CI, 0.32-0.79) for obese women (BMI ≥ 30 kg/m²). The aHR for each 5-kg/m² increase in BMI was 0.79 (95% CI, 0.69-0.90). Weight gain since early adulthood (age, 18 y) also was associated inversely with risk of microscopic colitis (Ptrend = .001). The aHR for each 10-kg weight gain since early adulthood was 0.85 (95% CI, 0.77-0.94). The associations were not modified by age, cohort, physical activity, or smoking status (all Pinteraction ≥ .26).

CONCLUSIONS

Unlike many other immune- and metabolic-related disorders, obesity and weight gain since early adulthood were associated with a lower risk of microscopic colitis, based on an analysis of participants in the NHS and NHSII.

Marked regional variations in the prevalence of inflammatory bowel disease in a limited geographical region are not associated with compounds in the drinking water

Objective: The incidence of autoimmune diseases, especially inflammatory bowel disease (IBD), has increased substantially. Globally, there are vast differences varying from 0.2/10⁵ in some Asian countries to over 80/10⁵ in the Faroe Islands. Environmental factors have been suggested as triggers. The aim was to investigate the incidence and prevalence of IBD in the 33 municipalities in the county Scania in Southern Sweden, an area comprising 100 × 100 km with 1,274,069 inhabitants. Furthermore, we wanted to explore whether compounds in the drinking water could contribute to IBD; one report from Norway has suggested that iron in drinking water could contribute to UC.Methods: Patients with CD and UC were identified through the ICD-10 diagnosis database during the period 2000-2013. Water analyses for pH, alkaline, nitrate, sulphate, iron, magnesium and calcium were based on established methods and compared with the prevalence of IBD using Student's t-test.Results: A total number of 8925 patients were identified. The incidence for CD and UC were high (mean 16.4/10⁵, range 13.6-17.9 and 25.3/10⁵, range 21.3-28.0, respectively). The prevalence varied substantially (p < .0001 for both; CD mean 0.30%, range 0.15-0.42 and UC mean 0.42%, range 0.32-0.56). No correlation between IBD and the chemical compounds in the drinking water could be shown.Conclusions: The incidence rates of both CD and UC were high. The prevalence varied from 200% to 300% between the municipalities, despite the limited geographical area indicating that local conditions are of importance. However, chemical compounds in the water were not associated with this variation.

Smoking and Risk of Microscopic Colitis: A Systematic Review and Meta-analysis

BACKGROUND

The association between smoking and inflammatory bowel disease has long been recognized, but its role in the development of microscopic colitis is less well defined. This systematic review and meta-analysis was conducted with the aims to identify all available studies on the association between smoking and risk of microscopic colitis and to synthesize their results.

METHODS

The MEDLINE and EMBASE databases were searched from inception to May 2018 for cohort studies and case-control studies that compared the risk of microscopic colitis among current/former smokers vs individuals who have never smoked. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were extracted from the included studies and pooled together using a random-effects model, generic inverse variance method of DerSimonian and Laird. Between-study heterogeneity was quantified using the Q statistic and I2. Publication bias was assessed using funnel plots.

RESULTS

Seven studies (2 cohort studies and 5 case-control studies) with 262,312 participants met the eligibility criteria and were included in the meta-analysis. Relative to never-smokers, current smokers had significantly increased odds of microscopic colitis, with a pooled OR of 2.99 (95% CI, 2.15-4.15; I2, 64%). Former smokers also had significantly higher odds of microscopic colitis compared with never-smokers, with a pooled OR of 1.63 (95% CI, 1.37-1.94; I2, 0%). Funnel plots were symmetric and did not provide suggestive evidence of publication bias for both analyses.

CONCLUSIONS

The current systematic review and meta-analysis found a significantly higher risk of microscopic colitis among current smokers compared with never-smokers. The risk attenuated among former smokers but remained significantly higher among never-smokers.

Identification of Menopausal and Reproductive Risk Factors for Microscopic Colitis-Results From the Nurses' Health Study

BACKGROUND & AIMS

Microscopic colitis is a chronic inflammatory disorder of the colon primarily affecting postmenopausal women. However, the relation between hormonal determinants, including reproductive and menopausal factors, and risk of microscopic colitis has yet to be characterized.

METHODS

We collected data from 227,766 women who participated in the Nurses' Health Study (NHS) and the NHSII without a baseline history of microscopic colitis. Reproductive and menopausal factors were assessed in 1988 in the NHS and 1989 in the NHSII and updated biennially. Cases of microscopic colitis were confirmed through review of pathology records. We used Cox proportional hazards modeling to estimate hazard ratios and 95% confidence intervals.

RESULTS

Through 2014 in the NHS and 2015 in the NHSII, we confirmed 275 incident cases of microscopic colitis over 5,147,282 person-years. Compared with never use, current use of menopausal hormone therapy was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 2.64; 95% confidence interval 1.78-3.90). The risk increased with longer duration of use (P for trend < .0001) and decreased after discontinuation (P for trend = .002). The association did not differ according to disease subtype (P for heterogeneity = .34). Similarly, ever use of oral contraceptives was associated with increased risk of microscopic colitis (multivariable-adjusted hazard ratio 1.57; 95% confidence interval 1.16-2.13). There were no associations between age at menarche, parity, age at first birth, age at menopause, or menopause type and incident microscopic colitis.

CONCLUSIONS

In 2 large prospective cohort studies, we observed an association between exogenous hormone use and incident microscopic colitis. Further studies are needed to determine the mechanisms underlying these associations.

Microscopic colitis in Denmark and Sweden: incidence, putative risk factors, histological assessment and endoscopic activity

OBJECTIVE

The significantly higher incidence rates of microscopic colitis (MC) in Denmark compared to Sweden remains unexplained.

METHODS

Consecutive patients with newly diagnosed MC in the neighbouring regions of Skåne in 2011-2015 and Zealand in 2010-2016 were prospectively identified. Data on large bowel endoscopies and biopsies rates were retrieved. Information on putative factors were obtained from registers and literature. Interobserver agreement between pathologists from both regions on 40 blinded hematoxylin and eosin (H&E)-stained colon biopsies (collagenous colitis (CC), lymphocytic colitis (LC), non-specific inflammation and normal) was evaluated using kappa statistics.

RESULTS

The mean annual incidence per 10⁵ inhabitants in Skåne and Zealand 2010-2015 was 5.9 (95% CI 4.6-7.3) versus 16.4 (95% confidence intervals (95% CI) 13.6-19.2) for CC and 2.7 (95% CI 1.0-4.3) versus 11.1 (95% CI 8.8-13.4) for LC, respectively. Number of endoscopies with biopsy per 1000 and the rate of MC per endoscopy with biopsy was higher in Zealand (34-52/1000) than in Skåne (12-21/1000). The kappa value for overall agreement between pathologists was good (0.72; 95% CI 0.64-0.79). Prescription of proton pump inhibitors and selective serotonin reuptake inhibitors was higher in Skåne in the relevant age groups and prescription of non-steroidal anti-inflammatory drugs and smoking rate higher in Zealand. Alcohol consumption was higher in Denmark than in Sweden.

CONCLUSION

The incidence of MC and number of cases per colonic biopsy was higher in Zealand and could not be readily explained by endoscopy or biopsy rates, differences in histological assessment or putative risk factors.

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.

Early Life Exposure, Lifestyle, and Comorbidity as Risk Factors for Microscopic Colitis: A Case-Control Study

BACKGROUND

The pathophysiology of microscopic colitis (MC) is not fully understood. A dysregulation of the adaptive immune response has been hypothesized, of which the maturation and function is imprinted in early life. Various other factors (e.g., hormonal factors) have also been found to be associated, sometimes, with minimal or conflicting evidence. The aims of this study were to evaluate whether an exposure to (microbial) agents in early life might be protective for MC development and to assess the role of several less well-established risk factors in one study.

METHODS

A case-control study was conducted including MC cases diagnosed in the Southern part of the Netherlands between 2000 and 2012. Cases were matched to non-MC controls from the same area, based on gender and year of birth, and assigned the same index date. All subjects filled out the same study questionnaire on various risk factors.

RESULTS

In total, 171 MC cases and 361 controls were included. In the multivariable logistic regression analysis, current smoking (odds ratio 6.23, 95% confidence interval, 3.10-12.49), arthrosis, and a cardiac disorder were associated with MC. No association was observed, for example, factors related to early life exposure to microbial antigens, passive smoking, rheumatoid arthritis, celiac disease, or hormonal factors.

CONCLUSIONS

Early life exposure to microbial antigens and increased hormonal exposure were not found to be protective for MC. Current smoking seems to be an incontestable risk factor for MC. Therefore, exposure to environmental risk factors later may be of relevance in MC pathogenesis and warrants further investigation.

Family history, comorbidity, smoking and other risk factors in microscopic colitis: a case-control study

OBJECTIVES

Data on heredity, risk factors and comorbidity in microscopic colitis, encompassing collagenous colitis (CC) and lymphocytic colitis (LC), are limited.

AIM

The aim was to carry out a case-control study of family history, childhood circumstances, educational level, marital status, smoking and comorbidity in microscopic colitis.

METHODS

A postal questionnaire was sent in 2008-2009 to microscopic colitis patients resident in Sweden and three population-based controls per patient, matched for age, sex and municipality.

RESULTS

Some 212 patients and 627 controls participated in the study. There was an association with a family history of microscopic colitis in both CC [odds ratio (OR): 10.3; 95% confidence interval (CI): 2.1-50.4, P=0.004] and LC (OR not estimated, P=0.008). Current smoking was associated with CC [OR: 4.7; 95% CI: 2.4-9.2, P<0.001) and LC (OR: 3.2; 95% CI: 1.6-6.7, P=0.002). The median age at diagnosis was around 10 years earlier in ever-smokers compared with never-smokers.CC was associated with a history of ulcerative colitis (UC) (OR: 8.7, 95% CI: 2.2-33.7, P=0.002), thyroid disease (OR: 2.3; 95% CI: 1.1-4.5, P=0.02), coeliac disease (OR: 13.1; 95% CI: 2.7-62.7, P=0.001), rheumatic disease (OR 1.9; 95% CI: 1.0-3.5, P=0.042) and previous appendicectomy (OR: 2.2; 95% CI: 1.3-3.8, P=0.003), and LC with UC (OR: 6.8; 95% CI: 1.7-28.0, P=0.008), thyroid disease (OR: 2.4; 95% CI: 1.1-5.4, P=0.037) and coeliac disease (OR: 8.7; 95% CI: 2.8-26.7, P<0.001).

CONCLUSION

Association with a family history of microscopic colitis indicates that familial factors may be important. The association with a history of UC should be studied further as it may present new insights into the pathogenesis of microscopic colitis and UC.

Diagnosis and Management of Microscopic Colitis

Microscopic colitis (MC) is a relatively common cause of chronic watery diarrhea, especially in older persons. Associated symptoms, including abdominal pain and arthralgias, are common. The diagnosis is based upon characteristic histological findings in the presence of diarrhea. The two types of MC, collagenous and lymphocytic colitis, share similar clinical features, with the main difference being the presence or absence of a thickened subepithelial collagen band. There are several treatment options for patients with MC, although only budesonide has been well studied in multiple controlled clinical trials. This review will describe the clinical features, epidemiology, pathophysiology, diagnostic criteria, and treatment of patients with MC.