Incidence of inflammatory bowel disease across Europe: is there a difference between north and south? Results of the European Collaborative Study on Inflammatory Bowel Disease (EC-IBD)

[Trends in the occurrence (1980-1999) and clinical features of Crohn's disease and ulcerative colitis in a university hospital in southeastern Brazil]

BACKGROUND

Crohn's disease and ulcerative colitis are regarded as uncommon in developing countries, but studies on their occurrence in Brazil are scarce. Aims - To determine the occurrence of Crohn's disease and ulcerative colitis in a Brazilian university hospital throughout a 20-year period, and analyze the demographical, clinical and evolutive features of these cases.

METHODS

The frequencies of new cases of Crohn's disease and ulcerative colitis admitted from January 1980 up to December 1999 were calculated and a descriptive analysis of the features of all cases seen from January 1990 up to December 1999 was performed.

RESULTS

A total of 257 new cases (126 with Crohn's disease and 131 with ulcerative colitis) was recorded. The frequencies of admissions for both Crohn's disease and ulcerative colitis have increased progressively from 40 up to 61 cases/10.000 new admissions and Crohn's disease gradually became more common than ulcerative colitis. For both diseases, there was predominance of women, age at admission in the range of 30-40 years, Caucasian origin, married state and non-smokers. Digestive symptoms presented were similar to those already described for both diseases and there were no differences between Crohn's disease and ulcerative colitis regarding the frequencies of general complaints and extra-intestinal manifestations (29.5% vs 23.3%), including thromboembolism (5.9% vs 5.4%). Obstruction and/or perforation were seen in up to 59.2% of Crohn's disease cases, whereas 53.7% of all ulcerative colitis cases presented as severe forms. In Crohn's disease cases with obstruction, smoking was significantly more common than in non-complicated cases. In ulcerative colitis cases of increased severity, general complaints, extra-intestinal manifestations and pancolitis were significantly more frequent than in less severe forms.

CONCLUSIONS

For the last 20 years, there have been an increased frequency of admission of inflammatory bowel diseases, and Crohn's disease have become more prevalent than ulcerative colitis. Demographical, clinical and evolutive features of these diseases seems to be similar to those already described, but there seems to be a predominance of more severe forms of both diseases.

Epidemiology of inflammatory bowel disease

The incidence of IBD has either continued to increase or has stabilized at a high rate in most developed countries, whereas the incidence continues to rise in regions where IBD had been less common. The prevalence has continued to increase as a result of a combination of previously rising incidence and improved survival. Regardless of the exact prevalence, the burden of disease in North America and Europe is significant. Studying the patterns of geographic variation and age and gender distribution may yield important clues to the cause of IBD.

High prevalence of undetected ulcerative colitis: data from the Nottingham fecal occult blood screening trial

OBJECTIVES

Inflammatory bowel disease (IBD) is usually diagnosed as a result of symptoms but occasionally is found during investigation for other conditions. An earlier report from Nottingham had found a high prevalence of previously undetected "asymptomatic" IBD detected as a result of colorectal cancer screening, and the aim of this study was to reassess the prevalence, symptoms, and outcome in these patients.

METHODS

We investigated subjects found to be fecal occult blood (FOB) positive in a randomized trial of FOB screening for colorectal cancer. All FOB-positive subjects were investigated by colonoscopy or flexible sigmoidoscopy and barium enema. Subjects with IBD were referred back to their general practitioner for any further investigation and treatment.

RESULTS

Seventy-five thousand two hundred fifty-three subjects (aged 45-74) were sent FOB tests and 44,838 (60%) completed a series of tests on one or more occasions. Of 133,000 test series, 1.5% were positive. During investigation 53 cases of previously undetected IBD (52 of ulcerative colitis) were found; 52% (27/52) had proctosigmoiditis only, whereas 25% (13/52) had pancolitis. Only 17% (9/52) were completely asymptomatic, with a half or more reporting some rectal bleeding (54%) or diarrhea (50%). The overall prevalence of undetected ulcerative colitis was 69/10(5) (95% CI = 50-88/10(5)) in people offered screening and 116/10(5) (95% CI = 85-147/10(5)) in people accepting screening and was higher in men. Of 32 subjects followed up 2-12 yr after diagnosis, 91% (29) continued to have few or no symptoms, with only 12 currently receiving any treatment for their colitis.

CONCLUSIONS

In comparison with detected disease, undetected ulcerative colitis is relatively common but does usually cause some symptoms. It generally appears to follow a benign course, but a significant proportion have extensive colitis and may therefore be at an increased risk of colorectal cancer.

Measles vaccination and inflammatory bowel disease: controversy laid to rest?

The increasing incidence of Crohn's disease has lead to speculation about changes in exposures to environmental or infectious agents. Considerable attention has focused on the role of measles infection and/or vaccination in the pathogenesis of Crohn's disease and ulcerative colitis. Current evidence regarding the association between measles vaccination and inflammatory bowel disease (IBD) comprises analytic epidemiological studies, a case-series report and ecological studies. The first of these, a 1995 cohort study, found an association between measles vaccination and Crohn's disease and ulcerative colitis, but was widely questioned on methodological grounds. This was followed by a 1997 case-control study showing no association between measles vaccination and IBD. In 1998, public concern was rekindled by a report of 12 children with nonspecific colitis, ileal-lymphoid-nodular hyperplasia, and developmental disorders largely attributed to measles-mumps-rubella vaccine, but the nature of the report limited its scientific conclusions. Two additional studies, one case-control and one cohort, then followed and neither found an association with measles vaccination. Of the several ecological studies of measles vaccine coverage or measles schedule changes, none found an association with rates of IBD. The role of measles infection in IBD has been examined more extensively with studies of in utero measles exposure, measles infection early in life, and laboratory based investigations. An initial report of high rates of Crohn's disease among pregnancies affected by measles infection was followed by negative studies. Numerous case-control and ecological studies of children with measles infections early in life have also had discordant findings. Of three recent cohort studies, two showed no relationship between infection with early measles exposure and risk for IBD, while one found an approximate 3-fold elevation in risk. Laboratory investigations into persistent measles infection and IBD have been contentious. While some investigators have claimed to find persistent measles infection among patients with IBD, others, using highly sensitive polymerase chain reaction techniques, have not been able to replicate the findings. Recent controversy has centred on whether there is any evidence for molecular mimicry in the pathogenesis of IBD. In summary, available evidence does not support an association between measles-containing vaccines and risk of IBD, nor between measles infection and IBD. While further research is necessary into the causal factors underlying Crohn's disease and ulcerative colitis, continued public education efforts are needed to reassure the public about vaccine safety and to prevent declines in vaccine coverage.

Assessing health-related quality of life in patients with inflammatory bowel disease, in Crete, Greece

BACKGROUND

Health Related Quality of Life (HRQoL) is an important outcome measure in Inflammatory Bowel Disease (IBD). The aim of our study was to assess HRQoL in a population of 135 Greek patients with IBD.

METHODS

A cohort of 135 patients with IBD, 81 with ulcerative colitis (UC) and 54 with Crohn's disease (CD) were enrolled in our study. Demographic and disease-related data were recorded. HRQoL was assessed by a disease-specific and a generic questionnaire, IBDQ and SF-36, respectively. Disease activity was assessed by Harvey-Bradshaw Index and the Colitis Activity Index for CD and UC patients, respectively.

RESULTS

Among all variables recorded in our study, only disease activity had a significant effect on HRQoL. Patients with active disease scored significantly lower on both IBDQ and SF-36 when compared to those in remission. Only two among the four IBDQ dimensions, bowel and systemic, had significant ability in distinguishing best patients in remission from those with active disease.

CONCLUSIONS

IBD has a negative impact on HRQoL. Patients with active disease are more impaired than patients in remission. In our population of patients bowel and systemic dimensions had a predominant value in patients' perception of quality of life. Patients in our study using the same instrument scored higher than previously reported.

Evidence for a NOD2-independent susceptibility locus for inflammatory bowel disease on chromosome 16p

Heritable predisposition to inflammatory bowel disease (IBD) has been demonstrated by epidemiological and genetic analysis. Linkage of IBD to broad regions of chromosome 16 has been established by analysis of multiple populations. NOD2, located on proximal 16q, was recently identified as an IBD gene. As the linkage regions on chromosome 16 are large, we have investigated the possibility that NOD2 is not the only IBD gene located on this chromosome. A high-density experiment using 39 microsatellite markers was performed to identify additional regions of association, and to indicate areas of interest for further investigation. A triple-peaked configuration of the linkage curve with peak logarithm of odds (lod) scores of 2.7, 3.2, and 3.1 was observed on proximal 16p, proximal 16q, and central 16q, respectively. The cohort was stratified by coding individuals carrying the NOD2 single nucleotide polymorphism (SNP)8 and SNP13 "unknown." Significance at the central peak, corresponding to the genomic location of NOD2, then decreased from 3.2 to 1.2. The maximal lod scores on the proximal p-arm (lod = 2.1) and central q-arm (lod = 2.6) changed only moderately. An exploratory association analysis (TRANSMIT) yielded a strong lead at D16S3068 (P = 0.00028). The region around this marker was further investigated by using anonymous SNPs. An associated haplotype containing three SNPs was identified (peak significance P = 0.00027, IBD phenotype). On stratification based on NOD2 genotype, this significance increased to P = 0.0001. These results confirm the importance of NOD2 and provide evidence for a second IBD gene located on chromosome 16p.

Lipoprotein (a), thrombophilia and inflammatory bowel disease

Thrombophilia in inflammatory bowel disease may be due to several risk factors, such as a dysbalanced haemostasis with a hypercoagulative state, thrombocytosis, hyperfibrinogenaemia and hyperhomocysteinaemia. In addition, increased concentrations of lipoprotein (a), a modified form of low-density lipoprotein particles, have been associated with a higher risk of thrombotic vascular disease, probably due to inhibition of (local and endothelial) fibrinolysis. The mechanisms regulating the plasma concentration of lipoprotein (a) have not yet been elucidated completely, but genetic factors are involved. Dietary factors seem to play a minor role. In this issue of the journal, Koutroubakis et al. report that lipoprotein (a) concentration is elevated in patients with Crohn's disease, but not in patients with ulcerative colitis. Several other (apo)lipoproteins have a different pattern in patients with inflammatory bowel disease than in a control population of healthy subjects from Crete. These findings add up to the multifactorial nature of thrombophilia in inflammatory bowel disease patients, especially in patients with Crohn's disease, and give rise to speculations about the clinical significance of the observed different lipoprotein metabolism in patients with inflammatory bowel disease.

Increasing incidence of both juvenile-onset Crohn's disease and ulcerative colitis in Scotland

OBJECTIVE

A previous study reported a three-fold rise in the incidence of juvenile-onset Crohn's disease in Scottish children and a marginal fall in ulcerative colitis between 1968 and 1983. The present study aimed to document the incidence of juvenile-onset inflammatory bowel disease between 1981 and 1995 and examine temporal trends between 1968 and 1995 in Scotland.

SETTING

Scotland (latitude 55-60 degrees N) has a total area of 77 837 km2 (30 405 square miles) and includes four urban centres each with a population of over 100,000.

PARTICIPANTS

The Scottish hospital discharges linked database was used to identify 1002 patients less than 19 years old who were coded as having inflammatory bowel disease between 1981 and 1997. All case notes were reviewed and diagnoses verified. Incident cases were defined as those with symptom onset before or at 16 years of age between 1 January 1981 and 31 December 1995.

RESULTS

During the 15 year period 1981-1995, 438 incident cases of Crohn's disease and 227 of ulcerative colitis were identified, giving standardized incidences of 2.5 cases and 1.3 cases per 100,000 population per year for Crohn's disease and ulcerative colitis respectively. On 31 December 1995 there were 150 children < or = 16 years of age with Crohn's disease and 101 with ulcerative colitis, giving crude prevalences of 13.7 cases per 100,000 population for Crohn's disease and 9.2 for ulcerative colitis. The continuing rise in Crohn's disease incidence between 1981 and 1995 fits that predicted by linear trend analysis of the 1968-1983 data. The incidence of Crohn's disease in the 12-16 age range almost doubled between 1981 and 1995 and was greater for males than females. Ulcerative colitis incidence was thought to show a slight fall in the 1968-1983 data, but this is reversed in the 1981-1995 data.

CONCLUSION

The incidence of juvenile-onset Crohn's disease continues to rise in Scotland and the prevalence has increased by 30% since 1983. Unlike the previous report from Scotland, the incidence of juvenile-onset ulcerative colitis also is apparently rising. Whether this represents a real rise in incidence, or merely the inclusion of milder cases which were not previously hospitalized remains uncertain.

Quality of health care in inflammatory bowel disease: development of a reliable questionnaire (QUOTE-IBD) and first results

OBJECTIVES

As inflammatory bowel disease is a chronic disorder, usually with an early onset in life, quality of care plays an important role for patients. The aim of this study was to develop a questionnaire to measure quality of care through the eyes of patients with inflammatory bowel disease.

METHODS

Ten generic questions were already available because the questionnaire is based on an existing instrument. Patients with inflammatory bowel disease in seven countries were involved in the development of additional disease-specific items. Validation and first field testing of the total questionnaire (QUOTE-IBD) was performed in The Netherlands.

RESULTS

A total of 380 patients cooperated in the development of 13 disease-specific items, with high internal reliability (Cronbach's alpha = 0.83). Another 162 patients were involved in validating and testing of the QUOTE-IBD, which consists of 23 items in total. Pearson's correlation coefficient between QUOTE-IBD and visual analog scale scores of health care items was 0.55. Intraclass correlation coefficient of two assessments was 0.64. First testing showed that patients gave relatively poor marks to some part of health care services, such as providing information about extraintestinal complaints and the psychological as well as physical approach to complaints.

CONCLUSIONS

A short, valid, reliable questionnaire was developed to measure the opinions of patients with inflammatory bowel disease on quality of health care. The QUOTE-IBD can be used for identification of areas for improvement, with the aim of optimizing health care in inflammatory bowel disease.

Crohn's disease and Mycobacterium avium subsp. paratuberculosis: current issues

Crohn's disease is a chronic debilitating inflammatory bowel disease of unknown etiology. Proposed causes include bacterial or viral infection, diet or exposure to tobacco smoke, genetic abnormality, and immune dysfunction. The bacterium Mycobacterium avium subsp. paratuberculosis (Map) has received much research attention as a potential cause of the disease. Map causes Johne's disease in ruminants. The pathology of Johne's disease superficially resembles that of Crohn's disease in humans. Some researchers have shown evidence of Map in intestinal tissues of Crohn's disease patients. Studies are in progress to investigate the possibility that Map exists in milk from infected cows and survives pasteurization. This is a controversial subject with the potential for media attention and public outcry. We examined the current literature and concluded that insufficient evidence exists at this time to implicate any one factor, including Map in milk, as the definitive cause of Crohn's disease. The high degree of uncertainty in this issue requires regulators to recognize the need for effective risk communication as ongoing research provides additional information about the disease.

Factor V Leiden and prothrombin gene mutation in inflammatory bowel disease in a Mediterranean area

BACKGROUND

Thromboembolism has been reported to be associated with inflammatory bowel disease.

AIM

To evaluate the association of factor V Leiden and prothrombin gene mutation with inflammatory bowel disease in a population of patients with thromboembolic events and inflammatory bowel disease and in a control population of patients with inflammatory bowel disease without thromboembolic events.

PATIENTS AND METHODS

A series of 18 patients with inflammatory bowel disease and a history of arterial or venous thrombosis and 45 patients with inflammatory bowel disease without thromboembolic events were evaluated for the presence of factor V Leiden and prothrombin gene mutation. Frequency of gene mutation was compared with its occurrence in 100 healthy controls.

RESULTS

One patient with inflammatory bowel disease without thromboembolic events was heterozygous for factor V Leiden mutation. whereas no patient with a thromboembolic event had factor V Leiden mutation. No patients (either cases or controls) had prothrombin gene mutation. In the healthy population the frequency of factor V Leiden and prothrombin mutation was 5% and 2%, respectively.

CONCLUSIONS

Data emerging from the present study do not support any role of factor V Leiden and prothrombin gene mutation as the cause of thromboembolism in inflammatory bowel disease.

Clinical features in familial cases of Crohn's disease and ulcerative colitis in Italy: a GISC study. Italian Study Group for the Disease of Colon and Rectum

OBJECTIVE

Previous studies have reported genetic anticipation, genomic imprinting, and phenotypic concordance of some clinical features in familial cases of Crohn's disease (CD) and ulcerative colitis (UC). The aim of our study was to investigate the phenotypic features of affected members in a large sample of CD and UC Italian families.

METHODS

In a multicenter study, CD and UC families were recruited. Affected members were questioned about date of birth, gender, age at onset of symptoms and at diagnosis, location and extension of disease, occurrence of extraintestinal manifestations, use of steroids and/or of immunosuppressive drugs, need for resective surgery, and number of relapses per year (< 1 yr or > or = 1 yr). Statistical analysis was performed with chi2, Fisher's, Mann-Whitney U, and binomial probability tests, when appropriate.

RESULTS

A total of 128 families with 270 affected members were studied: 35 were CD, 64 UC, and 29 mixed families (when UC and CD affected different members). In 99 of 128 families (77%), the diagnosis was concordant. In CD families, a high concordance for localization (46%), extraintestinal manifestations (67%), need for steroids (77%), need for immunosuppressive drugs (100%), need for surgery (29%), and relapse rate (36%) was found. In UC families, a high concordance for disease extension (33%), need for steroids (47%), and relapse rate (34%) was disclosed. A higher than expected concordance for ileal localization (p < 0.4) in CD families and extensive colitis (p < 0.05) in UC families was demonstrated. A generation difference of 15-20 yr in mean ages at onset of symptoms and at diagnosis was recorded. No features of more aggressive disease in subsequent generations and no differences in gender of transmitting parents and relatives were found.

CONCLUSIONS

Our study shows a high rate of concordance for diagnosis and clinical features in UC and, especially, CD families. The disease occurred 15-20 yr earlier than in previous generations without features of increased severity.

Inflammatory bowel disease: clinics and pathology. Do inflammatory bowel disease and periodontal disease have similar immunopathogeneses?

Inflammatory bowel disease (IBD) comprises two chronic, tissue-destructive, clinical entities Crohn disease (CD) and ulcerative colitis (UC) both apparently caused by immunological overreaction (hypersensitivity) to commensal gut bacteria. Under normal conditions the intestinal immune system shows a down-regulating tone ('oral tolerance') against dietary antigens and the indigenous microbiota. This local homeostasis is disturbed in IBD, leading to hyperactivation of T helper 1 (Th1) cells with abundant secretion of interferon-gamma and tumor necrosis factor (TNF) and production of IgG antibodies against commensal bacteria. In addition, UC includes genetically determined autoimmunity, particularly IgG1-mediated cytotoxic epithelial attack. Breaching of the epithelium is the best-defined event underlying abrogation of oral tolerance, but immune deviation caused by cytokines fiom irritated epithelial cells or subepithelial elements (for example, mast cells, natural killer cells, macrophages) may also be involved. Endogenous infection with local hypersensitivity likewise causes periodontal disease, reflecting 'frustrated' immune elimination mechanisms entertained by antigens from dental plaque. Altogether, perturbation of a tightly controlled cytokine network, with abnormal crosstalk between several cell types, apparently explains the progressive immunopathology of chronic inflammatory mucosal diseases in general. This adverse development will be influenced by numerous immunity genes, the dosage and potential pathogeniciy of commensal bacteria, general health, nutritional status, and psychological factors. Several targets for new therapy have tentatively been identified to block immunopathological mechanisms in IBD, and inhibition of TNF has a striking beneficial effect in CD, supporting a central role of this cytokine.

Evaluation of serologic disease markers in a population-based cohort of patients with ulcerative colitis and Crohn's disease

BACKGROUND

The sensitivity of assays for antineutrophil cytoplasmic antibody (ANCA), anti-Saccharomyces cerevisiae antibody (ASCA), and antipancreatic antibody (PAB) in different laboratories is unknown. Likewise, the sensitivity and diagnostic usefulness of these assays in patients with inflammatory bowel disease (IBD) in the community is unknown.

METHODS

An incidence cohort of 290 patients with IBD were offered participation in the study. Blood was obtained from 162 patients (56%) (83 with ulcerative colitis, 79 with Crohn's disease) who agreed to participate. ANCA was determined in five laboratories. ASCA in two laboratories, and PAB in one laboratory.

RESULTS

In ulcerative colitis, the sensitivity of ANCA determined in five laboratories varied widely, ranging from 0-63%. In Crohn's disease, the sensitivity of ASCA determined in two laboratories did not vary significantly, ranging from 39-44%; and the sensitivity of PAB determined in one laboratory was 15%. The optimal diagnostic usefulness was obtained from one laboratory where the positive predictive values of a positive ANCA assay combined with a negative ASCA assay for ulcerative colitis, and a negative ANCA combined with a positive ASCA for Crohn's disease, were 75% and 86%, respectively.

CONCLUSIONS

In patients with IBD, the sensitivity of ANCA varied widely in different laboratories, whereas the prevalence of ASCA was similar. The positive predictive values of the ANCA assay combined with the ASCA assay for ulcerative colitis and Crohn's disease are high enough to be clinically useful.

Epidemiology of inflammatory bowel disease in Asia

Studies of Asians in Asia show relatively low incidence rates for ulcerative colitis and Crohn's disease compared with North America and Europe. The prevalence of ulcerative colitis in migrant South Asians in Europe is similar to Europeans, whereas the prevalence of Crohn's disease for migrant South Asians in Europe is decreased compared with Europeans. The prevalence for both ulcerative colitis and Crohn's disease in Japan and Korea is relatively low. There are no obvious differences in age or sex distribution or rates of familial aggregation, and there are no significant differences in the clinical characteristics and natural history of ulcerative colitis and Crohn's disease in Asians compared with other racial groups with inflammatory bowel disease.

Association between insertion mutation in NOD2 gene and Crohn's disease in German and British populations

Background Genetic predisposition to inflammatory bowel disease (IBD) has been shown by epidemiological and linkage studies. Genetic linkage of IBD to chromosome 16 has been previously observed and replicated in independent populations. The recently identified NOD2 gene is a good positional and functional candidate gene since it is located in the region of linkage on chromosome 16q12, and activates nuclear factor (NF) kappaB in response to bacterial lipopolysaccharides. Methods We sequenced the coding region of the NOD2 gene and genotyped an insertion polymorphism affecting the leucine-rich region of the protein product in 512 individuals with IBD from 309 German or British families, 369 German trios (ie, German patients with sporadic IBD and their unaffected parents), and 272 normal controls. We then tested for association with Crohn's disease and ulcerative colitis. Findings Family-based association analyses were consistently positive in 95 British and 99 German affected sibling pairs with Crohn's disease (combined p<0.0001); the association was confirmed in the 304 German trios with Crohn's disease. No association was seen in the 115 sibling pairs and 65 trios with ulcerative colitis. The genotype-specific disease risks conferred by heterozygous and homozygous mutant genotypes were 2.6 (95% CI 1.5-4.5) and 42.1 (4.3-infinity), respectively. Interpretation The insertion mutation in the NOD2 gene confers a substantially increased susceptibility to Crohn's disease but not to ulcerative colitis.

An open-labeled, randomized study comparing systemic interferon-alpha-2A and prednisolone enemas in the treatment of left-sided ulcerative colitis

OBJECTIVE

The aim of this study was to compare the treatment efficacies of subcutaneous interferon-alpha-2A (IFN-alpha-2A) injections versus prednisolone enemas in active left-sided ulcerative colitis in an open-labeled, randomized study.

METHODS

Sixteen ulcerative colitis patients received IFN-alpha-2A subcutaneously (dosage: first wk, 9 MIU three times weekly [t.i.w.]; second wk, 6 MIU t.i.w.; wk 3-12, 3 MIU t.i.w.), and 16 received prednisolone enemas for 30 days (100 ml once daily, 0.25 mg of prednisolone/ml). The Powell-Tuck Index, Inflammatory Bowel Disease Questionnaire (IBDQ) score, and rectal histological activities were assessed before and after treatment. Thirteen patients in the IFN-alpha-2A group and all 16 in the prednisolone enema group completed the treatment.

RESULTS

IFN-alpha-2A treatment showed significant improvements in the Powell-Tuck Index (p = 0.0002), IBDQ score (p = 0.002), and rectal histological activity scores (p = 0.02). In the enema group, significant improvements were found in the Powell-Tuck Index (p = 0.0009), whereas no significant improvements were detected in the IBDQ scores (p = 0.055) or rectal histological scores (p = 0.052). There were no differences between scores of the two groups either before or after treatment. Only moderate side effects from the IFN-alpha-2A treatment were seen during the first 2-4 wk of treatment.

CONCLUSION

IFN-alpha-2A treatment resulted in significant depression of the disease activity as reflected by the Powell-Tuck Index, IBDQ score, and histological disease activity scoring. The preliminary trial thus suggests that IFN-alpha-2A may be effective in the treatment of active left-sided ulcerative colitis. Larger, randomized trials are, however, warranted to confirm this finding, owing to possible type II errors in group comparisons.

The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: a histologic and molecular study

Granulomatous appendicitis is an enigmatic entity. Purported causes include Crohn's disease, foreign body reactions, sarcoidosis, and infectious agents; however, most cases remain idiopathic. Yersinia enterocolitica (YE) and Y. pseudotuberculosis (YP) have been implicated as causes of appendicitis, ileocolitis, and mesenteric adenitis. The authors examined the potential role of YE and YP in granulomatous appendicitis using histologic and molecular methods. Forty cases of granulomatous appendicitis were evaluated for histologic features including transmural inflammation, number and character of granulomas, and mucosal changes. Twort Gram, Grocott methenamine-silver (GMS), and Ziehl-Neelsen stains were evaluated, and polymerase chain reaction (PCR) analysis was performed to identify pathogenic YP and YE. Twenty-five percent (10 of 40) of the cases were positive for pathogenic Yersinia by PCR (four YE, four YP, and two with both species). Prominent histologic features included epithelioid granulomas with lymphoid cuffing, transmural inflammation with lymphoid aggregates, mucosal ulceration, and cryptitis. One Yersinia-positive case contained mural Gram-negative bacilli; fungal and acid-fast bacilli stains were all negative. Except for one culture-negative case, serologies and cultures were not done or results were unavailable. Two Yersinia-positive patients were diagnosed subsequently with Crohn's disease, suggesting a possible relationship between the two entities. No other patients developed significant sequelae. YE and YP are important causes of granulomatous appendicitis, and Yersinia infection may mimic Crohn's disease. No histologic features distinguish reliably between Yersinia species, or between Yersinia-positive and Yersinia-negative cases. Because special stains and cultures are often not diagnostic, PCR analysis is an excellent technique for the diagnosis of Yersinia.

A critical review of epidemiological studies in inflammatory bowel disease

This review addresses the difficulty in interpreting the results of epidemiological studies in IBD and in making meaningful comparisons between studies. Both ulcerative colitis and Crohn disease appear to be more common in some industrialized countries such as Scandinavia, United Kingdom, North America and less common in Central and Southern Europe, Asia and Africa. Given data showing an increased incidence of ulcerative colitis in the United Kingdom, it is crucial that more studies be conducted in developing countries. While the incidence of Crohn disease has increased strikingly in many areas, the incidence of ulcerative colitis has remained fairly stable in most. This could be due to the rising number of community-based studies, as well as the improved accuracy in diagnosing Crohn disease. Although, the incidence of IBD among Blacks in Africa is low, infection rates are high, life expectancy is lower than in developed countries. Data from the USA suggest that rates are similar in Afro-American and Caucasian populations. Rates for Jewish populations may be slightly higher than in non-Jewish populations but this also varies geographically. Careful attention to genetic, environmental, and socioeconomic factors must be accounted for in these studies. There is no strong evidence to support that IBD is more common in urban than in rural settings and migration towards more accessible health care has not been adequately addressed. Recent epidemiological studies suggest that mortality rates for IBD are similar to that of the general population for the majority of patients. However, older patients with IBD and newly diagnosed cases with severe diseases are at increased risk of dying. Epidemiological studies remain important in assisting with health policy planning and in hypothesis testing of etiological factors. As better diagnostic techniques become widely available and public health registries are increasingly used, it is possible that geographic differences will diminish. International collaborative studies will be better equipped to answer research questions addressing risk factors and disease natural history. We have summarized in Table V the essential criteria to conduct a sound epidemiological study, which would permit future testing of hypotheses among different populations.

A close relationship of triplet repeat polymorphism in MHC class I chain-related gene A (MICA) to the disease susceptibility and behavior in ulcerative colitis

Major histocompatibility complex (MHC) class I chain-related gene A (MICA) has been found near the HLA-B gene. The MICA molecule is exclusively expressed on gastrointestinal epithelium and recognized by intestinal epithelial gamma delta T cells, where it exhibits a triplet repeat polymorphism in the transmembrane region. We investigated the possible correlation between MICA genetic polymorphism and ulcerative colitis (UC). Eighty-three patients with UC and 132 unrelated controls were included in this study. All subjects were Japanese. A triplet repeat polymorphism in the transmembrane region of the MICA was determined by direct sequencing procedures after amplification by a polymerase chain reaction. A significantly higher allele and phenotype frequencies of MICA A6 allele were observed in patients with UC than controls (allele frequency: P(c)=0.000011, phenotype frequency: P(c)=0.0049 odds ratio=2.62). A6 homozygous patients with UC showed significantly earlier onset of UC than patients without the A6 allele ((P)c=0.0042). Phenotypes of MICA A6 allele in Japanese are closely related to the disease susceptibility and behavior in UC. Examinations of MICA polymorphism in other ethnic groups may provide important information about the locus of primary responsible gene for UC.

Disease outcome in inflammatory bowel disease: mortality, morbidity and therapeutic management of a 796-person inception cohort in the European Collaborative Study on Inflammatory Bowel Disease (EC-IBD)

BACKGROUND

The course of inflammatory bowel diseases (IBD) has mainly been studied using different methods in single patient cohorts. The aim of the present study was to assess clinical aspects of disease outcome in a population-based cohort of IBD patients over a 4-year period in multiple centres across Europe.

METHODS

A total of 796 patients with IBD diagnosed in 10 centres between October 1991 and October 1993, registered at the EC IBD study centre (98% of the original cohort), participated in the study. Investigators filled out a standard follow-up form containing questions on the method of follow-up, vital status of the patient, change in diagnosis, extraintestinal manifestations, medical and surgical treatment, and physician's global assessment of disease activity.

RESULTS

Complete relief of the complaints was reported in 255 (48%) patients with ulcerative colitis (UC), 9 (50%) with indeterminate colitis (IC), but only in 87 (35%) of patients with Crohn disease (CD). Improvement was reported in 195 (37%) patients with UC, 113 (45%) with CD and 6 (33%) with IC. During the 4-year follow-up period, 23 patients died (14 UC, 8 CD. and 1 IC). The mean age at death was 69.3 years (s, 14.9 years). The deaths of three patients were recorded as directly due to IBD.

CONCLUSIONS

With the present approach to therapeutic management the short-term outcome of patients with IBD seems to be favourable in 10 medical centres in the north and south of Europe. However, more detailed studies including both objective and subjective measures are necessary.

Inflammatory bowel disease: epidemiology and management in an English general practice population

BACKGROUND

Inflammatory bowel diseases have significant long-term morbidity and healthcare resource consequences. Studies based on secondary care records may have underestimated the contribution of general practitioners (GPs) to its management.

AIMS

To describe the epidemiology and management of inflammatory bowel disease using GP records as the primary data source.

METHODS

A systematic search of GP clinical records in northern England, identifying cases of inflammatory bowel disease, patient consultation behaviour, prescribing patterns, and extent of specialist care.

RESULTS

In a population of 135 723, the incidence of ulcerative colitis was 13. 9/100 000 per year (CI: 7.5-20.3) and for Crohn's disease 8.3/100 000 per year (CI: 3.4-13.2). The age-sex adjusted point prevalence for ulcerative colitis on 1st January 1995 was 243.4/100 000 (CI: 217.4-269.4) and for Crohn's disease 144.8/100 000 (CI: 124.8-168.8). The mean number of consultations (s.d.) with specialists and GPs were similar, both in the first 12 months after referral (specialists 3.94 +/- 3.15, GPs 3.34 +/- 3.55) and in the most recent 12 months (1.02 +/- 2.02, 1.04 +/- 2.04). Only 29.9% of all patients were definitely under specialist care.

CONCLUSIONS

Prevalence rates, but not incidence rates, for inflammatory bowel disease are substantially higher than previously described in UK populations. General practitioners make a significant contribution to meeting the healthcare needs of these patients.

Concordance of inflammatory bowel disease among Danish twins. Results of a nationwide study

BACKGROUND

Previous studies have shown an increased risk of inflammatory bowel disease (IBD) among relatives of patients with Crohn disease and ulcerative colitis. In the present study the probandwise concordance rates for ulcerative colitis and Crohn disease among mono- and dizygotic twins were estimated. Further we aimed to evaluate whether smoking habits might influence the concordance, and to look for clinical characteristics of concordant versus discordant twin pairs.

METHODS

Among the 38,507 identified twins born in Denmark from 1953 to 1982, a questionnaire was sent to the 34,076 who previously had accepted to participate in studies. For twins reporting IBD, the diagnosis was verified by applying standard criteria to records requested from hospitals or practitioners.

RESULTS

Among the 29,421 (86.3%) twins answering the questionnaire, 103 pairs had at least one twin who suffered from IBD. In the Crohn disease group five of 10 monozygotic pairs, but none of 27 dizygotic pairs were concordant. In the ulcerative colitis group three of 21 monozygotic, and two of 44 dizygotic pairs were concordant. The probandwise concordance rate among monozygotic pairs was 58.3% for Crohn disease and 18.2% for ulcerative colitis; among the dizygotic pairs the rates were 0 and 4.5%, respectively. The frequency of smokers was higher among twins with Crohn disease and lower among twins with ulcerative colitis compared to the frequency in the twin register. Furthermore, smoking habits were found to be of significance for discordance for disease. Regarding the clinical characteristics no homogenous pattern was observed within the concordant pairs and the differences between concordant and discordant pairs were not significant.

CONCLUSION

The observation of a significantly higher concordance rate among monozygotic than among dizygotic twin pairs strongly points to a genetic influence on occurrence of IBD, which seems to be more pronounced with regard to Crohn disease than to ulcerative colitis. Differences in smoking habits among the members of the discordant twin pairs may influence the discordance.

The epidemiology and the pathogenesis of inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) is still unknown. However, a satisfactory solution cannot be far away. IBD actually encompasses two diseases, i.e. Crohn's disease (CD) and ulcerous colitis (UC). These diseases resemble each other so closely that they cannot be distinguished even pathologically, but differ from each other sufficiently to regard them as independent entities. Epidemiological observations may be helpful in identifying the true causative factors of this evasive disease. Geographically, the prevalence of the disease has a slope from North to South and, to a lesser degree, from West to East. The Western-Eastern discrepancy can be attributed to a difference in Western life styles. The incidence of the disease has been increasing world-wide of late, but its spread has been slowing down in highly affected countries. Racial and ethnic relations in different populations and immigration studies offer interesting data which can reflect genetic, inherited, environmental and behavioural factors. The disease seems to have a characteristic racial-ethnic distribution: the Jewish population is highly susceptible everywhere, but its prevalence in that population nears that of the domestic society in which they live. In Hungary, the Roma (Gypsies) have a considerably lower prevalence than the average population. This can be attributed to a genetic or environmental influence. According to age, the onset of the disease occurs more often in the second or the third decade of life, but there also is another peak in the 60s. Regarding sexual distribution, there is a slight preponderance of colitis ulcerosa in men and of Crohn's disease in women. It may correspond to the stronger auto-immune affection in the process of Crohn's disease. Environmental factors and behavioural influences also are investigated. Diet, the role of the early ages, smoking habits and the influence of hormonal status and drugs are viewed as useful contributing factors in the manifestation of the disease. Genetic studies show that one-fourth of IBD patients have an affected family member. HLAB27 histocombatibility also plays an important, but not determining role in the development of the disease. Genetic factors seem to have a stronger influence in Crohn's disease than ulcerative colitis. The existence of multiple sclerosis-IBD families may reflect the common genetic background or the similar microbial effect as well. A great number of bacterial and viral factors has been suspected of being infectious factors in IBD, mostly in CD. Mycobacteria, Yersinia, Campylobacter, Clostridium, Clamidias, etc. as well as bacteria and some viruses such as herpes and rotavirus and the primary measles virus. None of them has been proven as a real and exclusively pathogenic factor. Immunological background has an important function in the manifestation of the disease. If an individual has a genetic susceptibility to infections, the down regulation of an inflammation in the bowel wall does not occur in a proper way. This initiates the auto-immune process which is a self-increasing cycle. Extra-intestinal manifestations of IBD are of high importance because they can not only follow intestinal symptoms, but precede them by years. Hepatic and biliary disturbances (primary sclerosing cholangitis), are the most serious complications. Mucocutaneous manifestations can be the first appearance of the main disease (in the mouth). Auto-immune consequences (erythema nodosum) or complications caused even by the therapy can occur. Ocular and musculoskeletal manifestations supposedly have the same genetic background and often precede the intestinal symptoms. Considering the epidemiological, genetic and immunological data, we can conclude that ulcerative colitis and Crohn's disease are heterogeneous disorders of mutifactorial etiology in which hereditary (genetic) and environmental (microbial, behaviour) factors interact to produce the disease.

Does the failure to acquire helminthic parasites predispose to Crohn's disease?

Two polarized patterns (Th1 and Th2) of cytokines regulate inflammatory responses. Each cytokine pattern inhibits production of the opposing pattern. Lymphocytes from inflamed intestine due to Crohn's disease secrete a Th1 pattern of cytokines. Crohn's disease is most prevalent in highly industrialized countries with temperate climates. It occurs rarely in tropical third world countries with poor sanitation. We propose that exposure to an environmental agent predisposes individuals to Crohn's disease. Parasitic worms (helminths) are common in tropical climates and in populations subject to crowding and poor sanitation. Children are most subject to helminthic colonization. Many helminths live within or migrate through the human gut where they interact with the mucosal immune system. The host mounts a mucosal response that includes Th2 cytokine production limiting helminthic colonization. Helminths and their eggs probably are the most potent stimulators of mucosal Th2 responses. The Th2 response provoked by parasitic worms can modulate immune reactions to unrelated parasitic, bacterial, and viral infections. Many people in developed countries now live in increasingly hygienic environments, avoiding exposure to helminths. Perhaps failure to acquire these parasites and experience mucosal Th2 conditioning predisposes to Crohn's disease, which is an overly active Th1 inflammation.

Influence of quality of care on quality of life in inflammatory bowel disease (IBD): literature review and studies planned

Inflammatory bowel disease (IBD) is a chronic disorder with an early onset in life. Therefore, it is reasonable to assume that IBD patients are in considerable need of health care. The quality of life of IBD patients is reported to be impaired. Whether optimizing the quality of health care for these patients may positively influence their quality of life is a question that has been raised often during recent years. This review of the literature on health care research discusses different concepts regarding the quality of care assessment in chronic disease, stresses the need to see things from the patient's perspective, and provides recommendations to optimize health care research. The two most important conclusions that can be drawn are that: (1) the relationship between quality of health care and quality of life in IBD is one that is certainly worth studying; and (2) when developing a means to assess patient data on quality of care, it is essential to involve patients from the very start.

Changes in the incidence of inflammatory bowel disease: what does it mean?

A sharp rise in the incidence of inflammatory bowel disease (IBD) has been observed in the western world since the early 1950s. The increase in the incidence of ulcerative colitis preceded the increase in the incidence of Crohn's disease by about 10-15 years. In high-incidence areas, a female preponderance at a young age (20-40 years) is observed in Crohn's disease, whereas in ulcerative colitis male incidence is still high at older ages. IBD is more common in the developed world than in the developing world and, in both the United States and Europe, a north-south incidence gradient has been reported, with IBD more common in the north than in the south. There are also indications that, in typically low-incidence areas, more cases are being seen lately. At present, IBD is rather common in western Europe, affecting 0.5-1.0% of the population during their lifetime. It will be interesting to follow these temporal trends in the coming years, as they may teach us more about the role of environmental factors in the pathogenesis of IBD.

Racial differences in the prevalence of ulcerative colitis and Crohn's disease in Singapore

BACKGROUND

The aim of this study was to determine the prevalence rates of inflammatory bowel disease in the different races in Singapore.

METHODS

The patients studied consisted of 58 people with an established diagnosis of ulcerative colitis (UC) and Crohn's disease (CD) as determined by a combination of clinical, radiological, endoscopic and histological criteria. The patients were residents of a well-defined geographical area in the northern part of Singapore and had been referred to the single regional hospital. Epidemiological data including sex, age, ethnicity, family history and disease type and extent were collected from case records and patient interviews.

RESULTS

There were 37 UC and 21 CD patients. Of the patients with UC, 67.5% were Chinese, 13.5% were Malay and 19% were Indian. The CD group consisted of 81% Chinese, 9.5% Malay and 9.5% Indian patients. The study population from which the patients were drawn was approximately 0.5 million in size.

CONCLUSIONS

The overall prevalence of UC was 6 per 100,000 and of CD was 3.6 per 100,000 in Singapore. There were disproportionately more Indians suffering from UC, with a prevalence of 16.2 per 100,000 in comparison with six per 100,000 for Chinese and seven per 100 000 for Malays. The relative risk of UC in Indians is 2.9-fold greater than for the Chinese (CI= 1.25-6.7) which was statistically significant. This trend was not seen for CD.

Iron deficiency diminishes gallbladder neuronal nitric oxide synthase

BACKGROUND

Iron deficiency has been demonstrated in the prairie dog to result in cholesterol crystal formation and altered biliary motility. Gallbladder filling and emptying are influenced by both inhibitory and excitatory stimuli, with nitric oxide (NO) playing a key role in normal relaxation. Iron is a cofactor for nitric oxide synthase. Therefore, we tested the hypothesis that iron deficiency would result in diminished levels of gallbladder neuronal nitric oxide synthase (nNOS) but would not influence the gallbladder's response to excitatory stimuli.

MATERIALS AND METHODS

Twenty adult female prairie dogs were fed either an iron-supplemented (Fe(+)) (200 ppm) control diet (n = 10) or an iron-deficient (Fe-) (8 ppm) diet (n = 10) for 8 weeks. Fasting gallbladder volume was measured. Gallbladder muscle strips were harvested for response to excitatory stimuli and measurement of nNOS protein levels by Western blotting. Muscle strip response to a spectrum of doses of cholecystokinin, acetylcholine, and electrical field stimuli was determined, and the areas under the response curves were calculated.

RESULTS

Gallbladder volume increased in the iron-deficient prairie dogs compared with the iron-supplemented group (1.45 +/- 0.27 mL vs 0.80 +/- 0.13 mL, P < 0.05). Iron deficiency diminished the ratio of gallbladder nNOS to beta-actin protein levels (0.05 +/- 0.01 vs 3.48 +/- 1.02, P < 0.05) but resulted in a normal response to excitatory stimuli.

CONCLUSIONS

We conclude that diminished gallbladder neuronal nitric oxide synthase contributes to the gallbladder stasis that occurs with iron deficiency. This phenomenon may contribute to the increased incidence of gallstones in premenopausal women.

Ulcerative colitis in Olmsted County, Minnesota, 1940-1993: incidence, prevalence, and survival

BACKGROUND

There is significant geographic variation in the reported incidence of ulcerative colitis.

AIMS

To update the incidence and prevalence of ulcerative colitis in Olmsted County, Minnesota, examine temporal trends, and determine overall survival.

PATIENTS

All Olmsted County residents diagnosed with ulcerative colitis between 1940 and 1993 (incidence cases), and all residents with ulcerative colitis alive on 1 January 1991 (prevalence cases).

METHODS

Incidence and prevalence rates were adjusted using 1990 US census figures for whites. The effects of age, sex, and calendar year on incidence rates were evaluated using Poisson regression. Survival from diagnosis was compared with that expected for US north-central whites.

RESULTS

Between 1940 and 1993, 278 incidence cases were identified, for an adjusted incidence rate of 7.6 cases per 100 000 person years (95% confidence interval (CI), 6.7 to 8.5). On 1 January 1991, there were 218 residents with definite or probable ulcerative colitis, for an adjusted prevalence rate of 229 cases per 100 000 (95% CI, 198 to 260). Increased incidence rates were associated with later calendar years (p<0.002), younger age (p<0.0001), urban residence (p<0.0001), and male sex (p<0.003). Overall survival was similar to that expected (p>0.2).

CONCLUSIONS

The overall incidence rate of ulcerative colitis in Olmsted County increased until the 1970s, and remained stable thereafter. Incidence rates among men and urban residents were significantly higher. The prevalence rate in Rochester in 1991 was 19% higher than that in 1980. Overall survival was similar to that of the general population.

Linkage of inflammatory bowel disease to human chromosome 6p

Inflammatory bowel disease (IBD) is characterized by a chronic relapsing intestinal inflammation. IBD is subdivided into Crohn disease and ulcerative colitis phenotypes. Given the immunologic dysregulation in IBD, the human-leukocyte-antigen region on chromosome 6p is of significant interest. Previous association and linkage analysis has provided conflicting evidence as to the existence of an IBD-susceptibility locus in this region. Here we report on a two-stage linkage and association analysis of both a basic population of 353 affected sibling pairs (ASPs) and an extension of this population to 428 white ASPs of northern European extraction. Twenty-eight microsatellite markers on chromosome 6 were genotyped. A peak multipoint LOD score of 4.2 was observed, at D6S461, for the IBD phenotype. A transmission/disequilibrium test (TDT) result of P=.006 was detected for D6S426 in the basic population and was confirmed in the extended cohort (P=.004; 97 vs. 56 transmissions). The subphenotypes of Crohn disease, ulcerative colitis, and mixed IBD contributed equally to this linkage, suggesting a general role for the chromosome 6 locus in IBD. Analysis of five single-nucleotide polymorphisms in the TNFA and LTA genes did not reveal evidence for association of these important candidate genes with IBD. In summary, we provide firm linkage evidence for an IBD-susceptibility locus on chromosome 6p and demonstrate that TNFA and LTA are unlikely to be susceptibility loci for IBD.

Risk of ulcerative colitis and Crohn's disease among offspring of patients with chronic inflammatory bowel disease

OBJECTIVE

The incidence of inflammatory bowel disease (IBD) varies among and within countries, but several studies have indicated that genetic factors may play an important role in the etiology of IBD. A Danish regional study has observed an almost 10-fold increased risk for ulcerative colitis (UC) and Crohn's disease (CD) among first-degree relatives of patients with these diseases. To give more precise risk estimates we conducted a nationwide study using population-based data from the Danish National Registry of Patients (NRP).

METHODS

All patients from the entire Danish population (5.2 million), who were discharged between 1977 and 1992 with a diagnosis of either UC or CD were extracted from the NRP. The offspring of these patients born in 1958 or later were identified in the Civil Registration System and subsequently linked to the NRP by means of the civil registration number. All Danish citizens alive or born on April 1, 1968 or later are registered in the Civil Registration System by a unique registration number, which includes the data of birth and links the offspring to their parents. The prevalence proportion ratio (PPR) was estimated by dividing the observed number of offspring with UC or CD, respectively, with the expected number of cases from the general population.

RESULTS

The PPRs of CD and UC among offspring of patients with UC were 2.6 and 5.1, respectively, and the PPRs of CD and UC among offspring of patients with CD were 12.8 and 4.0, respectively. All ratios were significantly increased.

CONCLUSION

The risk for UC and CD among offspring of patients with IBD is 2-13 times higher than the risk within the general population.

The effects of migration on ulcerative colitis: a three-year prospective study among Europeans and first- and second- generation South Asians in Leicester (1991-1994)

OBJECTIVE

Our aim was to measure prospectively the incidence of ulcerative colitis in Leicester City and to compare this with a previous retrospective study in the same area. We also sought to compare the incidence and disease extent in the European community with that of the South Asian community and to compare the disease extent between first- and second-generation South Asian migrants.

METHODS

A 3-yr prospective study of ulcerative colitis in the city of Leicester took place from October 1, 1991 to September 30, 1994 and included all cases resident in Leicester City and diagnosed as having ulcerative colitis, regardless of the extent and severity of the disease.

RESULTS

Extensive colitis was commoner in second-generation migrants than in the first generation (chi2 = 4.3, p = 0.04) and was comparable to the European community. The annual average incidence of ulcerative colitis was 9.1/10(5) population/yr (95% confidence interval [CI] 7.1-11.3), which is similar to the previous retrospective study. However, the annual average incidence of ulcerative colitis in the European population was 7.0/10(5) population/yr (95% CI 5-9.5), whereas that of the South Asian population was 17.2/10(5) population/yr (95% CI 11.8-24.3), confirming that the risk of ulcerative colitis in this particular community is exceptionally high.

CONCLUSIONS

These early results suggest that the disease pattern follows that of the indigenous population after only one generation and requires monitoring over the next decade. The incidence of ulcerative colitis in the South Asian population is high and continuing to rise.

Polymorphisms in tumour necrosis factor and adhesion molecule genes in patients with inflammatory bowel disease: associations with HLA-DR and -DQ alleles and subclinical markers

BACKGROUND

When investigating susceptibility to inflammatory bowel disease (IBD), a multifactorial disorder with a genetic predisposition, polymorphisms of molecules with immunoregulatory function are of potential interest. This is the first time that the polymorphisms of HLA-DR and -DQ, tumour necrosis factor (TNF), E-selectin (CD62E), L-selectin (CD62L), and intercellular adhesion molecule 1 (ICAM-1, CD54) were determined in Estonians, a population with a low IBD incidence rate, and their occurrence investigated in subgroups of a total of 53 IBD patients.

METHODS

The reverse hybridization principle and sequence specific primers were used for HLA genotyping. To analyse the TNF and adhesion molecule polymorphisms, the polymerase chain reaction with subsequent restriction fragment length polymorphism or single-strand conformation polymorphism method was used.

RESULTS

In the subgroup of antineutrophil cytoplasmic antibody (ANCA)-positive ulcerative colitis (UC) patients we found a higher frequency of the TNF2 (20.8% versus 0.0% in ANCA-negative UC patients, P = 0.051) and HLA-DRB1*15 allele (35.4% versus 15.7% in controls; P = 0.004). Of ANCA-positive UC patients 87.5% were carriers of one of these alleles (22.2% among ANCA-negative UC patients (P<0.001, Pc = 0.039) and 51.4% among controls (P = 0.002). Specific typing of HLA-DRB1*15 alleles showed that the HLA-DRB1*1501 allele was responsible for the HLA-DRB1*15 association with ANCA-positive UC. Associations of ICAM-1, E-selectin, or L-selectin polymorphisms with IBD were not found.

CONCLUSIONS

TNF2 and HLA-DRB1*15 alleles were associated with ANCA-positive UC in the investigated population. ANCA might be a useful marker, at least in some ethnic groups, for dividing IBD patients into genetically more homogeneous subgroups.

Epidemiology of Crohn's disease in Israel: a survey of Israeli kibbutz settlements

OBJECTIVE

The prevalence of Crohn's disease ranges from 10 to 70 cases per 100,000 population, and is 3-8 times more common among Jews. However, this excess risk is not evident in the Jewish population of Israel. Recently we have described a significant increase in the prevalence and incidence of Crohn's disease in the south of Israel. The aim of this study was to confirm this trend in a stable population found in communal (kibbutz) settlements.

METHODS

We repeated a community-based survey in 124,400 kibbutz residents, 10 yr after our first study. This population represents 5% of the Jewish population of Israel. All Crohn's disease patients were located by contacting the kibbutz clinics of the 269 kibbutz settlements (100% compliance). Data was updated to December 31st, 1997, which was designated the point prevalence date, and included information on gender, age, origin, education, profession, extent of the inflammatory process, clinical spectrum of the disease, therapy, complications of the disease, and treatment. The average annual incidence for the 10 yr was calculated from the prevalence data. Only cases with a definite diagnosis of Crohn's disease made in a recognized gastroenterology unit were accepted into the study.

RESULTS

There were 81 confirmed cases of Crohn's disease and the prevalence rate rose from 25.5/100,000 in 1987 to 65.1/100,000 in 1997 (p < 0.001). The mean annual incidence rate for this period (1987-1997) is 5.0/100,000/yr. Prevalence rates were higher in women than men, and in those born in Israel or Europe/America than in Asia/Africa. The mean age at presentation of the disease was lower in 1997 than in 1987, 37.4 +/- 17.0 and 45.0 +/- 17.0 yr, respectively (p = 0.041). Prevalence was highest in men with > 16 yr of education, and in women with 11-12 yr education, 119.7 and 100.3/100,000, respectively.

CONCLUSIONS

During the decade 1987-1997, the prevalence of Crohn's disease has increased in Israel and is approaching the rates in Europe and America.

Nutrition and inflammatory bowel disease: an update

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory process, the aetiology of which remains unknown. Nutrition may play an important role in the pathogenesis and treatment of IBD. The evidence regarding the role of specific dietary components in the pathogenesis of IBD is still inconclusive. Many studies have been subject to methodological limitations; studies of better design are necessary to confirm the hypothesis that nutritional factors may indeed play a role in the development of IBD. Several studies have reported nutritional and functional deficiencies in IBD patients, especially in Crohn's disease. It is, however, hard to discriminate between disease-induced and malnutrition-induced changes in nutritional parameters. Maintaining adequate nutritional status has been suggested to be beneficial to the course of the disease in IBD. Studies have provided further insight into the possible beneficial effects of nutritional supplementation as primary and adjunctive therapy in IBD. The effects of specific nutritional therapy may be caused by alterations in intestinal flora and hence in the production of intraluminal proinflammatory substances. Immunonutrients such as n-3 fatty acids and antioxidants may also play a role in the treatment of IBD. In this paper, the relation between nutritional aetiological factors, nutritional status and nutritional therapy is discussed in detail.

Epidemiology and the natural course of inflammatory bowel disease

Ulcerative colitis and Crohn's disease are inflammatory disorders of the gastrointestinal tract that are distributed unevenly within populations and throughout the world. Although the exact causes of inflammatory bowel disease (IBD) remain unknown, study of the epidemiology of IBD has provided insight into pathogenesis. This article examines the geographic, ethnic, and other trends of IBD; risk factors (including genetic and environmental); and the natural history of IBD.

Time trends in the incidence and disease location of Crohn's disease 1980-1995: a prospective analysis in an urban population in Germany

To determine the incidence and clinical pattern of Crohn's Disease in a defined area in Germany, a prospective, population-based study was carried out from 1980 to 1984 and again from 1991 to 1995. All patients newly diagnosed with Crohn's disease within the respective study period who were resident in the study area were included in the study. The results from both study periods were then compared to detect time trends. Altogether 288 (156 and 132, respectively) incident cases were identified yielding an almost unchanged incidence over the years (1980-84: 4.9/10(5); 1991-95 5.2/10(5)). While the peak of incidence is still in the 15-24-year-old group, 1 out of 5 incident patients is now age 50 years and older. Median age at onset of symptoms increased to 30 years (20 years in the former period). Time from onset of symptoms was reduced from a median of 20 months in the 1980s to 5 months. Symptoms did not change significantly, although there seems to be less complicated disease recently. Distal migration of the inflammation in the intestinal tract was observed with significantly more involvement of the sigmoid and rectum in the recent period.

Inflammatory bowel disease

Although ulcerative colitis and Crohn's disease are relatively uncommon disorders, most primary care practices include a number of individuals with these diagnoses. Much of the initial evaluation and long-term care of these patients is managed or coordinated by their primary care physicians. A familiarity with current principles of diagnosis and treatment is essential. Ulcerative colitis and Crohn's disease are related, immunologically mediated disorders of unknown cause. Both are characterized by chronic relapsing courses, frequent need for surgical intervention, and increased colorectal cancer risk. Significant differences are seen between these two inflammatory bowel disease syndromes, in their histopathologic features, clinical manifestations, and response to treatment. This review focuses on the colorectal manifestations of inflammatory bowel disease, emphasizing clinical presentation, approach to diagnosis, medical and surgical management, and long-term prognosis.

A genomewide analysis provides evidence for novel linkages in inflammatory bowel disease in a large European cohort

Inflammatory bowel disease (IBD) is characterized by a chronic relapsing intestinal inflammation, typically starting in early adulthood. IBD is subdivided into two subtypes, on the basis of clinical and histologic features: Crohn disease and ulcerative colitis (UC). Previous genomewide searches identified regions harboring susceptibility loci on chromosomes 1, 3, 4, 7, 12, and 16. To expand our understanding of the genetic risk profile, we performed a 9-cM genomewide search for susceptibility loci in 268 families containing 353 affected sibling pairs. Previous linkages on chromosomes 12 and 16 were replicated, and the chromosome 4 linkage was extended in this sample. New suggestive evidence for autosomal linkages was observed on chromosomes 1, 6, 10, and 22, with LOD scores of 2.08, 2.07, 2.30, and 1.52, respectively. A maximum LOD score of 1.76 was observed on the X chromosome, for UC, which is consistent with the clinical association of IBD with Ullrich-Turner syndrome. The linkage finding on chromosome 6p is of interest, given the possible contribution of human leukocyte antigen and tumor necrosis-factor genes in IBD. This genomewide linkage scan, done with a large family cohort, has confirmed three previous IBD linkages and has provided evidence for five additional regions that may harbor IBD predisposition genes.

Incidence of collagenous and lymphocytic colitis: a 5-year population-based study

OBJECTIVE

The incidence of collagenous and lymphocytic colitis is not well known. We sought to assess the incidence of collagenous and lymphocytic colitis in a well-defined population during a 5-yr study period.

METHODS

From January 1, 1993, to December 31, 1997, all new patients diagnosed with collagenous or lymphocytic colitis living in the catchment area of the Hospital Mutua de Terrassa (Barcelona, Spain) were identified. Since 1993 all patients with chronic diarrhea were referred for a diagnostic colonoscopy. Multiple biopsy sampling of the entire colon was performed when appearance of the colonic mucosa was grossly normal.

RESULTS

Twenty-three cases of collagenous colitis and 37 of lymphocytic colitis were diagnosed. The female:male ratios were 4.75:1 and 2.7:1 for collagenous and lymphocytic colitis, respectively. The mean age at onset of symptoms was 53.4+/-3.2 (range, 29-82) yr for collagenous colitis, and 64.3+/-2.7 (range, 28-87) yr for lymphocytic colitis (p = 0.012). The mean annual incidence per 100,000 inhabitants based on the year of onset of symptoms was 1.1 (95% confidence interval [CI], 0.4-1.7) for collagenous colitis, and 3.1 (95% CI, 2.0-4.2) for lymphocytic colitis. A peak incidence was observed in older women in both diseases. A rate of microscopic colitis of 9.5 per 100 normal-looking colonoscopies performed in patients with chronic watery diarrhea was observed. Normal rectal biopsies were found in 43 % and 8% of patients with collagenous and lymphocytic colitis, respectively.

CONCLUSIONS

The incidence of lymphocytic colitis is three times higher than that of collagenous colitis. Microscopic colitis should be considered as a major possibility in the work-up of chronic diarrhea in older women.