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

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

Background

Microscopic colitis (MC) has been associated with several immune-mediated diseases including psoriasis, but earlier research has been limited to psoriasis occurring before MC. Data from large-scale cohort studies investigating MC and risk of future psoriasis are lacking.

Objective

To examine the association between MC and psoriasis.

Methods

In a nationwide, population-based, matched cohort study in Sweden from 2007 to 2021, we identified 8404 patients with biopsy-verified MC (diagnosed in 2007-2017), 37,033 matched reference individuals, and 8381 siblings without MC. Information on MC was obtained through the ESPRESSO cohort (a Swedish histopathology database with nationwide coverage). Using Cox regression, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for psoriasis up until 2021.

Results

During a median follow-up of 9.2 years (interquartile range = 6.7-11.7), 179 MC patients and 440 reference individuals were diagnosed with psoriasis (241.1 vs 131.8 events per 100,000 person-years), corresponding to one extra case of psoriasis in 91 patients with MC over 10 years. After adjustment for the matching variables (birth year, sex, county of residence, and calendar period) and level of education, we computed an adjusted hazard ratio (aHR) of 1.82 (95% CI = 1.53-2.17). Stratified by sex, estimates were similar and when examining the aHR across different lengths of follow-up, we found significantly elevated estimates up to 10 years after MC diagnosis. Compared to MC-free siblings, the aHR was 1.85 (95% CI = 1.36-2.51).

Conclusion

Patients with MC are at an almost doubled risk of psoriasis compared to the general population. Clinicians need to consider psoriasis in MC patients with skin lesions.

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 rheumatoid arthritis: A nationwide population-based matched cohort study

BACKGROUND

Microscopic colitis (MC) has been linked to several autoimmune conditions. Results from previous studies on the association with rheumatoid arthritis (RA) have been inconsistent.

AIM

To assess the risk of future RA in MC.

METHODS

We conducted a nationwide matched cohort study in Sweden of 8179 patients with biopsy-verified MC (diagnosed in 2007-2017), 36,400 matched reference individuals and 8202 siblings without MC, with follow-up until 2021. Information on MC was obtained from all of Sweden's regional pathology registers (n = 28) through the ESPRESSO cohort. Data on incident RA were collected from the National Patient Register. Using Cox regression, we calculated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 9.1 years (interquartile range = 6.7-11.7), 73 MC patients and 183 reference individuals from the general population were diagnosed with RA (99 vs. 55 events per 100,000 person-years), equivalent to one extra case of RA in 226 patients with MC followed for 10 years. These rates corresponded to an aHR of 1.83 (95% CI = 1.39-2.41). The aHR was highest during the first year of follow-up (2.31 [95% CI = 1.08-4.97]) and remained significantly elevated up to 5 years after MC diagnosis (aHR 2.16; 95% CI = 1.42-3.30). Compared to siblings, without MC, the aHR was 2.04 (95% CI = 1.18-3.56).

CONCLUSION

Patients with MC are at a nearly two-fold risk of developing RA compared to the general population. Knowledge of this increased risk may expedite evaluation for RA in patients with MC presenting with joint symptoms and/or arthralgia, thus preventing delay until RA diagnosis.

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.

The impact of microbiota-derived short-chain fatty acids on macrophage activities in disease: Mechanisms and therapeutic potentials

Short-chain fatty acids (SCFAs) derived from the fermentation of carbohydrates by gut microbiota play a crucial role in regulating host physiology. Among them, acetate, propionate, and butyrate are key players in various biological processes. Recent research has revealed their significant functions in immune and inflammatory responses. For instance, butyrate reduces the development of interferon-gamma (IFN-γ) generating cells while promoting the development of regulatory T (Treg) cells. Propionate inhibits the initiation of a Th2 immune response by dendritic cells (DCs). Notably, SCFAs have an inhibitory impact on the polarization of M2 macrophages, emphasizing their immunomodulatory properties and potential for therapeutics. In animal models of asthma, both butyrate and propionate suppress the M2 polarization pathway, thus reducing allergic airway inflammation. Moreover, dysbiosis of gut microbiota leading to altered SCFA production has been implicated in prostate cancer progression. SCFAs trigger autophagy in cancer cells and promote M2 polarization in macrophages, accelerating tumor advancement. Manipulating microbiota- producing SCFAs holds promise for cancer treatment. Additionally, SCFAs enhance the expression of hypoxia-inducible factor 1 (HIF-1) by blocking histone deacetylase, resulting in increased production of antibacterial effectors and improved macrophage-mediated elimination of microorganisms. This highlights the antimicrobial potential of SCFAs and their role in host defense mechanisms. This comprehensive review provides an in-depth analysis of the latest research on the functional aspects and underlying mechanisms of SCFAs in relation to macrophage activities in a wide range of diseases, including infectious diseases and cancers. By elucidating the intricate interplay between SCFAs and macrophage functions, this review aims to contribute to the understanding of their therapeutic potential and pave the way for future interventions targeting SCFAs in disease management.

Appendectomy and Future Risk of Microscopic Colitis: A Population-Based Case-Control Study in Sweden

BACKGROUND AND AIMS

Microscopic colitis (MC) is an inflammatory bowel disease and a common cause of chronic diarrhea. Appendectomy has been suggested to have immunomodulating effects in the colon, influencing the risk of gastrointestinal disease. The relationship between appendectomy and MC has only been sparsely studied.

METHODS

This was a case-control study based on the nationwide ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) cohort, consisting of histopathological examinations in Sweden, linked to national registers. Patients with MC were matched to population controls by age, sex, calendar year of biopsy, and county of residence. Data on antecedent appendectomy and comorbidities were retrieved from the Patient Register. Unconditional logistic regression models were conducted presenting odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for country of birth and matching factors. Further subanalyses were made based on MC subtypes (lymphocytic colitis and collagenous colitis), follow-up time postappendectomy and severity of appendicitis.

RESULTS

The study included 14,520 cases of MC and 69,491 controls, among these 7.6% (n = 1103) and 5.1% (n = 3510), respectively, had a previous appendectomy ≥1 year prior to MC or matching date. Patients with a previous appendectomy had an increased risk of MC in total (OR, 1.50; 95% CI, 1.40-1.61) and per the collagenous colitis subtype (OR, 1.67; 95% CI, 1.48-1.88) or lymphocytic colitis subtype (OR, 1.42; 95% CI, 1.30-1.55). The risk remained elevated throughout follow-up, and the highest risk was observed in noncomplicated appendicitis.

CONCLUSIONS

This nationwide case-control study found a modestly increased risk of developing MC following appendectomy.

Adverse event profiles of microscopic colitis in the Japanese Adverse Drug Event Report (JADER) database

Microscopic colitis (MC) is a chronic inflammatory bowel disease that is characterized by nonbloody watery diarrhea. The epidemiology in Japan differs from that in Europe and the United States, but little information is available from epidemiological surveys of MC in Japan. This study aimed to provide a new hypothesis regarding the factors associated with MC by using the Japanese Adverse Drug Event Report (JADER) database. "Colitis microscopic" (preferred term code: 10056979) cases entered into the JADER database between 2004 and 2021 were analyzed. Of the 246,997 cases in the JADER database, 161 cases were observed to be associated with MC. A Weibull analysis revealed that the median onset duration of MC (interquartile range) was 72.5 (36.0‒125.5) days in lansoprazole users and 116.0 (60.3‒1089.0) days in aspirin users. A multiple logistic regression analysis revealed that MC was significantly associated with the female sex, as well as ages ≥ 60 years and drugs including lansoprazole, aspirin, and nicorandil. A subset analysis revealed that MC was positively associated with obesity in female cases. Our study cannot demonstrate a causal inference between MC and each drug; however, the findings suggest that MC was associated with nicorandil as well as with lansoprazole and aspirin.

The Therapeutic Effect of SCFA-Mediated Regulation of the Intestinal Environment on Obesity

Intestinal environment disorder is a potential pathological mechanism of obesity. There is increasing evidence that disorders in the homeostasis of the intestinal environment can affect various metabolic organs, such as fat and liver, and lead to metabolic diseases. However, there are few therapeutic approaches for obesity targeting the intestinal environment. In this review, on the one hand, we discuss how intestinal microbial metabolites SCFA regulate intestinal function to improve obesity and the possible mechanisms and pathways related to obesity-related pathological processes (depending on SCFA-related receptors such as GPCRs, MCT and SMCT, and through epigenetic processes). On the other hand, we discuss dietary management strategies to enrich SCFA-producing bacteria and target specific SCFA-producing bacteria and whether fecal bacteria transplantation therapy to restore the composition of the gut microbiota to regulate SCFA can help prevent or improve obesity. Finally, we believe that it will be of great significance to establish a working model of gut– SCFA– metabolic disease development in the future for the improvement this human health concern.

Red meat consumption, obesity, and the risk of nonalcoholic fatty liver disease among women: Evidence from mediation analysis

BACKGROUND

Previous studies have suggested consumption of red meat may be associated with an increased risk of developing nonalcoholic fatty liver disease (NAFLD). However, large-scale, prospective data regarding red meat consumption in relation to the incidence of NAFLD are lacking, nor is it known whether any association is mediated by obesity.

OBJECTIVE

We aimed to evaluate the relationship between red meat consumption and the subsequent risk of developing NAFLD.

DESIGN

This prospective cohort study included 77,795 women in the Nurses' Health Study II cohort without NAFLD at baseline (in 1995), who provided detailed, validated information regarding diet, including consumption of red meat, every 4 years, followed through 2015. Lifestyle factors, clinical comorbidities and body mass index (BMI), were updated biennially. Cox proportional hazard models were used to estimate multivariable adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Over 1,444,637 person years of follow-up, we documented 3130 cases of incident NAFLD. Compared to women who consumed ≤1 serving/week of red meat, the multivariable-adjusted HRs of incident NAFLD were 1.20 (95% CI: 0.97, 1.50) for 2-4 servings/week; 1.31 (95% CI: 1.06, 1.61) for 5-6 servings/week; 1.41 (95% CI: 1.13, 1.75) for 1 serving/day; and 1.52 (95% CI: 1.23, 1.89) for ≥2 servings/day. However, after further adjustment for BMI, all associations for red meat, including unprocessed and processed red meat, were attenuated and not statistically significant (all P-trend>0.05). BMI was estimated to mediate 66.1% (95% CI: 41.8%, 84.2%; P < 0.0001) of the association between red meat consumption and NAFLD risk.

CONCLUSIONS

Red meat consumption, including both unprocessed and processed red meat, was associated with significantly increased risk of developing NAFLD. This association was mediated largely by obesity.

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.

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.

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%, P_comparison < .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; P_{heterogeneity} = .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).

Weight gain during early adulthood, trajectory of body shape and the risk of nonalcoholic fatty liver disease: A prospective cohort study among women

BACKGROUND & AIMS

Obesity is established as a major risk factor for the development of nonalcoholic fatty liver disease (NAFLD). However, the influence of dynamic changes in adiposity over the life course on NAFLD risk remains poorly understood.

METHODS

We collected data from 110,054 women enrolled in the Nurses' Health Study II cohort. Early adulthood weight was ascertained at age 18 years, and weight gain since early adulthood was defined prospectively every 2 years. We used a group-based modeling approach to identify five trajectories of body shape from age 5 years up to age 50 years. NAFLD was defined by physician-confirmed diagnoses of fatty liver, after excluding excess alcohol intake and viral hepatitis, using validated approaches.

RESULTS

We documented 3798 NAFLD cases over a total of 20 years of follow-up. Compared to women who maintained stable weight (±2 kg), women with ≥20 kg of adulthood weight gain had the multivariable aHR of 6.96 (95% CI, 5.27-9.18), and this remained significant after further adjusting for early adulthood BMI and updated BMI (both P trend <0.0001). Compared to women with a medium-stable body shape trajectory, the multivariable aHRs for NAFLD were, 2.84 (95% CI, 2.50-3.22) for lean-marked increase, 2.60 (95% CI, 2.27-2.98) for medium-moderate increase, and 3.39 (95% CI, 2.95-3.89) for medium-marked increase.

CONCLUSIONS

Both early adulthood weight gain and lifetime body shape trajectory were significantly and independently associated with excess risk of developing NAFLD in mid-life. Maintaining both lean and stable weight throughout life may offer the greatest benefit for the prevention of NAFLD.

Mortality of Patients With Microscopic Colitis in Sweden

BACKGROUND & AIMS

Microscopic colitis is one of the most common causes of chronic diarrhea in older populations. We investigated all-cause and cause-specific mortality in patients with microscopic colitis.

METHODS

We conducted a nationwide cohort study of all cases of microscopic colitis (n = 14,333) diagnosed from 1990 through 2017 in Sweden. Cases of microscopic colitis were identified using SNOMED codes from gastrointestinal histopathology reports collected from Sweden's 28 pathology departments. Each case of microscopic colitis was matched to 5 population comparators (n = 68,700). Mortality data were ascertained from Sweden's cause of death register. We used Cox proportional hazards modeling to estimate adjusted hazard ratios (aHRs) and 95% CIs.

RESULTS

Through December of 2017, we confirmed 3014 deaths in patients with microscopic colitis (27.4/1000 person-years) and 12,534 deaths in matched population comparators (23.3/1000 person-years). This corresponded to a 10-year absolute risk difference of 3.4% (95% CI, 2.1%-4.6%) and an aHR of 1.17 (95% CI, 1.12-1.22). However, further adjustment of models for comorbidity burden reduced the relative risk of death for patients with microscopic colitis (aHR, 0.98; 95% CI, 0.94-1.02). In analyses of cause-specific death, microscopic colitis was associated with an increased risk of gastrointestinal-related death (aHR, 1.68; 95% CI, 1.38-2.05) and infection-related death (aHR, 1.42 ; 95% CI, 1.11-1.83), but not cancer-related death (aHR, 0.83; 95% CI, 0.76-0.91) or cardiovascular-related death (aHR, 1.02; 95% CI, 0.96-1.10).

CONCLUSIONS

In a nationwide cohort study in Sweden, we found that patients with microscopic colitis were at increased risk of death. However, the increase appears to be related to higher burden of comorbidities in this population.

Microscopic colitis and risk of cancer - a population-based cohort study

BACKGROUND AND AIMS

The association between microscopic colitis (MC) and cancer risk is unclear. Large, population-based studies are lacking.

METHODS

We conducted a nationwide cohort study of 11,758 patients with incident MC (diagnosed 1990-2016 in Sweden), 50,828 matched reference individuals and 11,614 siblings to MC patients. Data were obtained through Sweden´s pathology departments and from the Swedish Cancer Register. Adjusted hazard ratios (aHRs) were calculated using Cox proportional hazards models.

RESULTS

At the end of follow up (mean: 6.7 years), 1,239 (10.5%) of MC patients had received a cancer diagnosis, compared to 4,815 (9.5%) of reference individuals (aHR 1.08 (95%CI=1.02-1.16)). The risk of cancer was highest during the first year of follow up. The absolute excess risks for cancer at 5, 10 and 20 years after MC diagnosis were +1.0% (95%CI=0.4%-1.6%), +1.5% (0.4%-2.6%) and +3.7% (-2.3-9.6%), respectively, equivalent to one extra cancer event in every 55 individuals with MC followed for ten years.MC was associated with an increased risk of lymphoma (aHR 1.43, 1.06-1.92) and lung cancer (aHR 1.32, 1.04-1.68) but with decreased risks of colorectal (aHR 0.52, 0.40-0.66) and gastrointestinal cancers (aHR 0.72, 0.60-0.85). We found no association with breast or bladder cancer. Using siblings as reference group to minimize the impact of shared genetic and early environmental factors, patients with MC were still at an increased risk of cancer (HR=1.20; 95%CI=1.06-1.36).

CONCLUSIONS

This nationwide cohort study demonstrated an 8% increased risk of cancer in MC patients. The risk was highest during the first year of follow up.

Microscopic Colitis and Risk of Inflammatory Bowel Disease in a Nationwide Cohort Study

BACKGROUND & AIMS

Microscopic colitis shares pathogenetic mechanisms with inflammatory bowel disease (IBD). We studied the association between microscopic colitis and risk of incident IBD using data from a nationwide cohort study.

METHODS

We conducted a prospective cohort study of all adults who received a diagnosis of microscopic colitis from 1990 through 2017 in Sweden and risk of incident IBD. Cases of microscopic colitis (n= 13,957) were identified through Systematized Nomenclature of Medicine codes from the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, which included gastrointestinal pathology reports from all of Sweden's 28 centers. Individuals with microscopic colitis were matched to 5 general population controls (n = 66,820) and to unaffected siblings (n =13,943). Cox regression was used to estimate adjusted hazard ratio (aHRs) and 95% confidence intervals (CIs).

RESULTS

Through December of 2017, we identified 323 incident cases of ulcerative colitis (UC) and 108 incident cases of Crohn's disease (CD) in patients with microscopic colitis compared with 94 UC and 42 CD cases in population comparators. Mean times from diagnosis of microscopic colitis to diagnosis of CD was 3.3 ± 3.2 years and to diagnosis of UC was 3.2 ± 3.5 years. In multivariable models, microscopic colitis was associated with an aHR of 12.6 (95% CI 8.8-18.1) for CD, 17.3 (95% CI 13.7-21.8) for UC, and 16.8 (95% CI 13.9-20.3) for IBD. The 10-year absolute excess risks of CD and UC were 0.9 (95% CI 0.7-1.1) and 2.6 (95% CI 2.2-2.9) percentage points, respectively. In sensitivity analyses, comparing patients with microscopic colitis with their unaffected siblings, the aHRs of CD and UC were 5.4 (95% CI 3.2-9.2) and 9.4 (95% CI 6.4-13.8), respectively.

CONCLUSIONS

In a population-based study in Sweden, we found a significant increase in risk of incident IBD among patients with microscopic colitis. Future studies should focus on potential mechanisms underlying these observed associations.