Esophageal Lichen Planus: A Descriptive Multicenter Report.

GOALS: To better understand the characteristics, treatment approaches, and outcomes of patients with esophageal lichen planus (ELP). BACKGROUND: ELP is a rare, often unrecognized and misdiagnosed disorder. Data on this unique patient population are currently limited to small, single-center series. STUDY: A multicenter, retrospective descriptive study was conducted of adults diagnosed with ELP over a 5-year period, between January 1, 2015, and October 10, 2020, from 7 centers across the United States. RESULTS: Seventy-eight patients (average age 65 y, 86% female, 90% Caucasian) were included. Over half had at least 1 extraesophageal manifestation. Esophageal strictures (54%) and abnormal mucosa (50%) were frequent endoscopic findings, with the proximal esophagus the most common site of stricture. Approximately 20% had normal endoscopic findings. Topical steroids (64%) and/or proton pump inhibitors (74%) dominated management; endoscopic response favored steroids (43% vs. 29% respectively). Almost half of the patients required switching treatment modalities during the study period. Adjunctive therapies varied significantly between centers. CONCLUSIONS: Given its at times subtle clinical and endoscopic signs, a high index of suspicion and biopsy will improve ELP diagnosis, especially in those with extraesophageal manifestations. Effective therapies are lacking and vary significantly. Prospective investigations into optimal treatment regimens are necessary.

The Occurrence of Gastritis in Microscopic Colitis and Inflammatory Bowel Disease.

Multiple studies have shown that Helicobacter pylori infection is associated with a lower prevalence of inflammatory bowel disease (IBD).1,2 Besides chronic active gastritis (CAG) resulting from gastric infection with H pylori, pathologists have noticed another form of CAG, which is unrelated to H pylori infection and seems to cluster in patients with IBD.3-5 The aim of the present study was to compare the prevalence of H pylori-negative and H pylori-positive CAG in patients with IBD, and microscopic colitis (MC).

Incomplete Intestinal Metaplasia Is Rare in Autoimmune Gastritis.

BACKGROUND: Incomplete intestinal metaplasia (IM) is reportedly associated with higher gastric cancer (GC) risk than its complete variant. AGA Guidelines recommend including IM subtyping in routine pathology reports. This study assesses the prevalence of complete versus incomplete IM in gastric conditions with different GC risks. METHODS: IM subtyping (complete vs. incomplete) and grading (IM extension: G1: ≤30%; G2: >30%) were assessed in 386 patients with IM + ve gastric biopsy sets that included both antral and oxyntic samples. Cases were categorized as: (a) IM foci in otherwise normal mucosa (n = 59); (b) Helicobacter pylori gastritis (n = 138); (c) reactive gastropathy (141); and (d) autoimmune atrophic gastritis (AIG, n = 48). Odds ratios (OR) and their 95% CI were used in comparing the prevalence of incomplete IM and the correlation between subtype and IM extension. RESULTS: Incomplete IM was present in 37.7% of patients with H. pylori gastritis, 8.3% of those with AIG 5.0% of those with reactive gastropathy, and none of those with otherwise normal mucosa. Incomplete IM was strongly associated with more extensive (G2-IM) mucosal intestinalization (OR = 6.69; 95% CI = 2.77-9.40). CONCLUSION: Incomplete IM is significantly more prevalent in conditions (H. pylori gastritis) known to carry a higher risk of GC and is strongly associated with its extension. The low prevalence of incomplete IM in AIG (8.3%) and reactive gastropathy (5.2%) is in keeping with the low GC risk associated with these conditions.

Trends of Colonic Neoplasia in US Outpatient Endoscopy Centers.

BACKGROUND: A variety of studies have shown rising trends in the occurrence of colorectal cancer in younger patients as opposed to falling trends among older patients aged 55 years or more. We hypothesized that the time trends of benign colonic precursor lesions would reveal similar patterns. AIMS: The present study was designed to test this hypothesis in a large nationwide sample of the US population undergoing colonoscopy in community-based endoscopy centers. METHODS: The Inform Diagnostics database is an electronic repository of histopathologic records of patients distributed throughout the USA. A cross-sectional study analyzed the detection rates of sessile serrated adenomas (SSA), hyperplastic polyps (HP), tubular adenomas (TA), traditional serrated adenomas (TSA), or adenocarcinomas (colorectal cancer, CRC) in 2,910,174 colonoscopies done 2008-2020. RESULTS: During the 13-year time period, the rate of SSA showed a significant rise, both in patients younger and older than 55 years. HP and TA both showed a significant decline during the same time period. The trends of CRC in the older age group decreased significantly between 2008 (or its peak in 2012) and 2020. The trends of CRC in the younger age group increased significantly between 2008 and its peak in 2017. CONCLUSIONS: The age-specific time trends of benign and malignant colonic neoplasia are characterized by dissimilar temporal patterns. Such dissimilarity could suggest that besides a set of shared risk factors that affect all types of colonic neoplasia alike, there is yet another set of environmental risk factors that specifically influence malignant transformation.

Comorbid Occurrence of Eosinophilic Esophagitis and Inflammatory Bowel Disease.

In a previous study, we found a variety of inverse associations between the occurrence of gastroesophageal reflux disease (GERD) and the occurrence of various forms of inflammatory bowel disease (IBD), as well as microscopic colitis (MC) and its 2 subtypes of lymphocytic and collagenous colitis.1 Two recent studies suggested a 5-fold increase in the occurrence of eosinophilic esophagitis (EoE) among IBD patients.2,3 The aim of the present study was to confirm these positive associations between EoE and IBD.

Gastric granulomas and Helicobacter pylori: An incidental relationship.

AIMS: Studies investigating the relationship between granulomatous gastritis (GG) and Helicobacter pylori infection have been largely inconclusive. This study was designed to determine whether the analysis of a very large number of patients would provide clearer answers evaluate the association between H. pylori infection and gastric granulomas. METHODS: We used a large national database of clinicopathological data to extract 1,673,086 patients who underwent esophagogastroduodenoscopy with gastric biopsies between 2008 and 2020. In a case-control study, we evaluated the occurrence of H. pylori infection in patients with and without gastric granulomas. We also explored other clinical and histopathological associations. RESULTS: H. pylori infection was present in 44 of 496 (8.9%) patients with gastric granulomas, compared to 158,949 (9.5%) in the control group (OR = 0.93, 95% CI = 0.68-1.26). Of the 129 patients with gastric granulomas, 50 had documented inflammatory bowel disease. CONCLUSIONS: The results of this study show that the prevalence of H. pylori infection in patients with gastric granulomas is essentially identical to that of controls with no evidence of granulomas or granulomatous disease. When patients with and without a plausible-known association for gastric granulomas were analyzed separately, the prevalence of H. pylori infection remained remarkably similar in GG patients and controls. Considering the very large numbers of patients with gastric biopsies analyzed in this study, we submit that there is no basis for suggesting that H. pylori is etiologically related to GG.

The Meaning of Incidental Goblet Cells at the Gastroesophageal Junction.

BACKGROUND AND AIMS: The causes for the occurrence of goblet cells at the gastroesophageal junction (GEJ-GC) are unknown. The aim of our study was to compare the concurrent histologic changes of the stomach in (1) patients with GEJ-GC, but without Barrett's esophagus (BE) to those in (2) patients with BE and in (3) controls without GEJ-GC or BE. METHODS: We used an electronic database of histopathologic records from 1.3 million individual patients, who underwent esophago-gastro-duodenoscopy (EGD) in 2009-2018. We compared the prevalence of Helicobacter pylori-positive gastritis (HpG), gastric intestinal metaplasia (G-IM), chronic inactive gastritis (CIG), and reactive gastropathy (RG) among the 3 patient groups, using odds ratios and their 95% confidence intervals. RESULTS: Of all EGD patients, 4.0% harbored BE and 2.4% GEJ-GC. The average age of patients with GEJ-GC (60 ± 14) was significantly younger than the age of patients with BE (63 ± 12) and significantly older than the age of controls (55 ± 17). Female subjects were more common among GEJ-GC (54%) than BE (37%), but less common than among controls (63%). The 3 gastric histopathology changes associated with H. pylori were significantly more common in GEJ-GC than BE (for HpG 2.42, 2.29-2.56; for G-IM 1.82, 1.73-1.92; for CIG 1.31, 1.22-1.41). The corresponding differences between GEJ-GC and controls were less striking (for HpG 0.97, 0.93-1.01; for G-IM 1.15, 1.11-1.19; for CIG 0.90, 0.85-0.95). RG was slightly less common in GEJ-GC than BE (0.89, 0.86-0.92) and controls (0.94, 0.91-0.96). CONCLUSIONS: With respect to its demographic and histopathologic features, GEJ-GC likely represents gastric intestinal metaplasia as opposed to BE and should prompt gastric intestinal metaplasia screening and management.

Seasonal Variation of Duodenal Intraepithelial Lymphocytosis.

The increase of intraepithelial lymphocytes in architecturally normal duodenal mucosa is commonly referred to as duodenal intraepithelial lymphocytosis (DIL). The characteristic appearance of DIL corresponds with Marsh grade 1, that is, normal or mild increase in lamina propria inflammation of the duodenal mucosa, with no crypt hyperplasia or villous atrophy.1 Approximately 11% of DIL patients harbor clinical and serologic features suggestive of gluten sensitivity.2 An additional 2% of patients with DIL harbor concomitant microscopic colitis.3Helicobacter pylori gastritis may contribute to another 10%-15% of DIL, which may resolve following eradication of H pylori.4 In the majority of cases with DIL, however, its underlying cause has remained unknown.1 A study of the seasonal variations in the occurrence of DIL may provide additional clues about its yet unknown etiology.

Low Prevalence of Helicobacter pylori-Positive Peptic Ulcers in Private Outpatient Endoscopy Centers in the United States.

OBJECTIVES: During the past decades, the prevalence of gastric and duodenal ulcers, as well as Helicobacter pylori infection, has markedly declined. We hypothesized that the decline in H. pylori prevalence has decreased the fraction of H. pylori-positive gastric and duodenal ulcers. The present study was designed to test this hypothesis in a large US population undergoing esophagogastro-duodenoscopy in community-based endoscopy centers. METHODS: The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the United States. A cross-sectional study among 1,289,641 individual esophagogastro-duodenoscopy patients analyzed the prevalence of peptic ulcers stratified by age, sex, ethnicity, H. pylori status, year of diagnosis, and ulcer type. The joint influence of multiple predictor variables on the occurrence of gastric and duodenal ulcers was analyzed using multivariate logistic regression analysis. RESULTS: Between 2009 and 2018, the general prevalence of H. pylori infection fell significantly from 11% to 9%. This decline was accompanied by a similar decline in the fraction of H. pylori-positive gastric ulcers from 17% to 14% and H. pylori-positive duodenal ulcers from 25% to 21%. Nowadays, only 17% of all patients with ulcer harbor H. pylori. The fraction of H. pylori-positive ulcers was significantly greater in duodenal than in gastric ulcers and in male than in female patients with ulcer. The prevalence of H. pylori was 2.6-fold higher among Hispanics and 3.2-fold higher among East Asians compared with the general population. The H. pylori prevalence fell from 24% to 22% among Hispanics and from 21% to 15% among East Asians. In East Asians and Hispanics, the fraction of H. pylori-positive gastric ulcers was 37% and 35%, respectively. DISCUSSION: H. pylori infection continues to fall in the general population. Nowadays, even among patients with ulcer only a small minority harbors H. pylori infection.

Interaction Between Ethnicity and Helicobacter pylori Infection in the Occurrence of Reflux Disease.

BACKGROUND AND AIMS: Few reports are available to reliably assess the ethnic distribution of Barrett metaplasia and reflux esophagitis. The present study served to analyze the joint influence of Helicobacter pylori infection and patient demographics on the diagnoses of Barrett metaplasia and reflux esophagitis. METHODS: The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the United States. In a case-control study of 52,096 cases with Barrett metaplasia, 189,235 cases with reflux esophagitis, and 152,322 controls without any signs or symptoms suggestive of gastroesophageal reflux disease, we assessed the influence of age, gender, ethnicity, and H. pylori status on occurrence of Barrett metaplasia or reflux esophagitis. RESULTS: Barrett metaplasia was less common among East Asians (with odds ratio, 0.48; 95% confidence interval, 0.44-0.53) and Hispanics (0.60, 0.57-0.63) than other ethnic groups living in the United States. Reflux esophagitis was also less common among East Asians (0.86, 0.82-0.90), but more common among Hispanics (1.18, 1.14-1.21). Both types of esophageal disease were associated with a lower prevalence rates of gastric H. pylori infection than controls, with 0.48, 0.44-0.53 for Barrett metaplasia and 0.60, 0.57-0.63 for reflux esophagitis. The prevalence rates of gastric H. pylori and both esophageal diseases were greater in older than younger and male than female patients in all ethnic groups alike. CONCLUSIONS: Gastric H. pylori infection, ethnicity, gender, and age all influence the occurrence of Barrett metaplasia, and reflux esophagitis.

Upper Gastrointestinal Disease Influences the Occurrence of Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Compromise of the gastric acid barrier may facilitate bacterial invasion of the lower intestinal tract and influence the occurrence of inflammatory bowel disease (IBD). Our study tested the associations between histopathologic changes in the upper and lower gastrointestinal tract in patients undergoing bidirectional endoscopy. METHODS: The Inform Diagnostics database is a national electronic repository of histopathologic records of patients distributed throughout the entire USA. A case-control study among 302,061 patients, of whom 13,943 harbored IBD, evaluated whether the occurrence of Crohn's disease or ulcerative colitis was influenced by the presence of various upper gastrointestinal diagnoses associated with lowered gastric acid output. The influence of individual risk factors on the occurrence of colonic disease was expressed as odds ratios with their 95% confidence intervals. RESULTS: The odds ratio for Crohn's disease being associated with gastric H. pylori was 0.30 (0.24-0.37), with intestinal metaplasia 0.30 (0.24-0.39), with fundic gland polyps 0.42 (0.35-0.50), with gastric hyperplastic polyps 0.35 (0.23-0.51), with Barrett's metaplasia 0.19 (0.14-0.24), and with reflux esophagitis 0.46 (0.42-0.51). The odds ratio for ulcerative colitis being associated with gastric H. pylori was 0.58 (0.50-0.67), with intestinal metaplasia 0.39 (0.32-0.47), with fundic gland polyps 0.61 (0.53-0.71), with gastric hyperplastic polyps 0.64 (0.49-0.84), with Barrett's metaplasia 0.50 (0.43-0.59), and with reflux esophagitis 0.77 (0.71-0.84). CONCLUSIONS: A diminished gastric acid barrier function, as evidenced by various upper gastrointestinal diseases associated with lowered gastric acid output, may exert a protective influence against the development of inflammatory bowel disease.

Prevalence and concordant occurrence of esophageal, gastric, duodenal, and colonic eosinophilia.

Eosinophilic esophagitis, gastritis, duodenitis, and colitis are rare diseases. Few studies have been able to accumulate sufficiently large number of patients to analyze their clinical epidemiology. The aim of the present epidemiologic study was to examine the prevalence and concordant occurrence of gastrointestinal (GI) eosinophilia. Using a database of histopathologic records, a cross-sectional study among 302,061 patients undergoing bidirectional endoscopy evaluated the concordant occurrence of esophageal, gastric, duodenal, and colonic eosinophilia. The prevalence rates (PRs) of GI eosinophilia were expressed per 1,000 study subjects with their 95% Poisson confidence intervals (CIs). The concordant occurrence of various forms of GI eosinophilia was compared to their overall occurrence in the study population by calculating odds ratios (ORs) and their 95% CI. The database contained 3,008 patients with esophageal eosinophilia (PR = 9.96, 9.61-10.32), 366 patients with gastric eosinophilia (1.21, 1.09-1.34), 10 patients with duodenal eosinophilia (0.03, 0.02-0.06), and 124 patients with colonic eosinophilia (0.41, 0.34-0.49). The occurrence of esophageal eosinophilia was associated with an increased occurrence of gastric eosinophilia (OR = 3.58, 2.06-6.23), duodenal (40.22, 12.61-128.31), and colonic eosinophilia (8.12, 4.26-15.49). Similarly, we also found statistically significant associations between gastric eosinophilia and duodenal or colonic eosinophilia, and between duodenal and colonic eosinophilia. In the adult, as in the pediatric population, patients with any type of GI eosinophilia are at an increased risk for simultaneously harboring eosinophilia at multiple sites of their GI tract. With the exception of esophageal eosinophilia, however, other forms of GI eosinophilia are rarely diagnosed.

Associations of Microscopic Colitis With Other Lymphocytic Disorders of the Gastrointestinal Tract.

BACKGROUND & AIMS: Lymphocytic disorders of the upper and lower gastrointestinal tract seem to cluster in patients. We aimed to assess the frequency of comorbid occurrence of lymphocytic disorders in patients with microscopic colitis (MC). METHODS: We collected data from the Miraca Life Sciences Database, a large national electronic repository of histopathologic records of patients throughout the United States. In a population of 228,506 patients who underwent bidirectional endoscopy from January 2008 through July 2016, we studied the comorbid occurrence of celiac disease, duodenal intraepithelial lymphocytosis, lymphocytic gastritis, and lymphocytic esophagitis among 3456 patients with MC. Associations were described in terms of their odds ratios (OR) and 95% CIs. RESULTS: Any type of lymphocytic disorder occurred in 13.7% of patients with MC and 5.9% of patients without MC. The ORs of lymphocytic disorders in patients with MC were: 2.56 (95% CI, 2.32-2.82) for any type of lymphocytic disorder, 3.07 (95% CI, 1.25-7.52) for lymphocytic esophagitis, 15.05 (95% CI, 12.31-18.41) for lymphocytic gastritis, 1.73 (95% CI, 1.53-21.96) for duodenal intraepithelial lymphocytosis, and 6.06 (95% CI, 5.06-7.25) for celiac disease. Comorbidities were more common in patients with lymphocytic than collagenous colitis, with an OR of 1.74 (95% CI, 1.42-2.13). Patients with MC with comorbidities were significantly younger and had a lower proportion of men than patients with MC patients without comorbidities. Diarrhea was the predominant symptoms in all patients MC, irrespective of comorbidities. CONCLUSION: In a retrospective study, we identified lymphocytic disorders of the upper gastrointestinal tract that are significantly more common in patients with than without MC. These associations suggest the existence of an underlying etiology that is common to all lymphocytic disorders and that affects the upper and lower gastrointestinal tract.

Lesions of All Types Exist in Colon Polyps of All Sizes.

OBJECTIVES: Although large polyps are known to harbor more advanced neoplasia than small polyps, the extent of the relationship between size and type is not fully known. The study aim was to establish benchmarks for the prevalence of different histologic polyp types among varying size categories. METHODS: The Miraca Life Sciences Database is an electronic repository of histopathologic patient records from private practices throughout the United States. We extracted the records of 483,998 unique patients who underwent colonoscopy with polypectomy between January 2008 and December 2014. A total of 550,811 polyps were stratified by their endoscopic size measurement. Polyps of each size were further stratified as hyperplastic polyp (HP), tubular adenoma (TA), tubulovillous adenoma (TVA), sessile serrated adenoma/polyp, and adenocarcinoma. RESULTS: Of all 550,811 polyps, 447,343 (81%) were 1-9 mm in size, and 103,517 (19%) were 10 mm or larger. A fraction of 18,591/550,811 polyps (3.4%) harbored histologic features of advanced adenoma, such as TVA, high-grade dysplasia, or cancer. Of these, 4,725/18,591 (25%) occurred in polyps 1-9 mm and 13,868/18,591 (75%) occurred in polyps 10 mm or larger. The fractions of advanced adenoma were 0.6% (0.5-0.6%) in 1-5 mm polyps and 2.1% (2.0-2.2%) in 6-9 mm polyps, as compared to 13.4% (13.2-13.6%) in polyps 10 mm or larger. The frequency of HP significantly decreased with increasing polyp size, whereas the frequency of TA remained largely unaffected by polyp size. CONCLUSIONS: While advanced histopathology was found more frequently in colorectal polyps of larger than smaller size, one quarter of all advanced histopathology existed in polyps of <10 mm.

Increased Risk for Colon Polyps in Patients with Reflux Disease.

BACKGROUND: Previous studies have found an increased risk for colonic neoplasm in patients with Barrett's esophagus. It is unknown whether such risk applies similarly to other types of gastroesophageal reflux disease (GERD). AIMS: To test whether GERD represents a risk factor for the occurrence of colon polyps. METHODS: The Miraca Life Sciences Database is a large national electronic repository of histopathologic records of patients distributed throughout the entire USA. A case-control study evaluated whether presence of (1) Barrett's metaplasia, (2) erosive esophagitis on endoscopy or histologic signs of reflux esophagitis, (3) clinical diagnosis of GERD, (4) any type of GERD affected the occurrence hyperplastic polyps (HP), sessile serrated adenomas/polyps (SSA/P), or tubular adenomas (TA) among 228,506 subjects undergoing bidirectional endoscopy. Multivariate logistic regression analyses were used to calculate odds ratios and their 95% confidence intervals for the risk of HP, TA or SSA/P associated with various types of GERD and adjusted for age, sex, and presence of H. pylori. RESULTS: The analysis revealed positive associations between GERD and all types of colon polyps. These associations applied similarly to HP (1.47, 1.44-1.50), TA (1.30, 1.27-1.32), and SSA/P (1.52, 1.46-1.58). They also applied to different forms of GERD, showing a trend toward stronger associations, that is higher odds ratios, with Barrett's metaplasia or erosive esophagitis than clinical diagnosis of GERD. CONCLUSION: All types of GERD represent a risk factor for the occurrence of different colon polyps, such as HP, TA, or SSA/P.

The influence of Helicobacter pylori on the ethnic distribution of esophageal eosinophilia.

BACKGROUND: Environmental factors associated with ethnicity may contribute to the occurrence of eosinophilic esophagitis. Our study aimed to investigate the influence of Helicobacter pylori on the ethnic variation of esophageal eosinophilia in a large national sample of patients undergoing esophago-gastro-duodenoscopy. METHODS: The Miraca Life Sciences Database is an electronic repository of histopathologic patient records. A case-control study evaluated the influence of ethnicity on the occurrence of esophageal eosinophilia and how age, gender, and histologic diagnosis of H. pylori modify this relationship. RESULTS: The total study population comprised 596 479 subjects, of whom 25 969 harbored a diagnosis of esophageal eosinophilia. Young age, male sex, and H. pylori infection in declining order exerted the strongest influence on the occurrence of esophageal eosinophilia. In comparison with the population comprising of Caucasians and African-Americans, esophageal eosinophilia was less common among patients of African (OR=0.10, 95% CI=0.01-0.46), Middle Eastern (0.22, 0.15-0.31), East Asian (0.32, 0.26-0.38), Indian (0.28, 0.21-0.37), Hispanic (0.40, 0.37-0.43), or Jewish descent (0.58, 0.51-0.66), but more common among patients of Northern European descent (1.25, 1.07-1.45). With the exception of Northern Europeans, all ethnic subgroups were characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of esophageal eosinophilia (R2 =0.90, P<.001). CONCLUSION: Esophageal eosinophilia prevalence markedly varies by patient ethnicity. As there is a strong inverse correlation between H. pylori and esophageal eosinophilia, H. pylori infection may be in part responsible for the observed ethnic distribution of esophageal eosinophilia.

Interaction of Ethnicity and H. pylori Infection in the Occurrence of Microscopic Colitis.

BACKGROUND: Previous studies found that microscopic colitis is inversely associated with Helicobacter pylori infection and that microscopic colitis is characterized by a marked ethnic variation. AIM: The aim of the present study was to test whether an underlying ethnic variation of H. pylori infection is responsible for the ethnic variation of microscopic colitis. METHODS: The Miraca Life Sciences Database is a large national electronic repository of histopathologic records of patients distributed throughout the entire USA. A cross-sectional study evaluated the influence of age, gender, ethnicity, and histologic diagnosis of H. pylori on the occurrence of microscopic colitis among subjects who underwent esophago-gastro-duodenoscopies plus colonoscopy. RESULTS: The total study population comprised 228,506 subjects, of whom 28,890 carried a diagnosis of H. pylori gastritis and 3460 microscopic colitis. Female sex, old age, and H. pylori infection exerted the strongest influence on the occurrence of microscopic colitis. In comparison with the population comprising Caucasians and African-Americans, microscopic colitis was less common among subjects of Hispanic (0.34, 0.27-0.47), East Asian (0.13, 0.06-0.22), Indian (0.31, 0.10-0.73), or Middle Eastern descent (0.28, 0.07-0.74). All these ethnic subgroups were also characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of microscopic colitis (R 2 = 0.91, p < 0.001). CONCLUSION: Ethnic variations in the gastric infection with H. pylori may be partly responsible for the observed ethnic distribution of microscopic colitis.