Incidence of inflammatory bowel disease in northern France (1988-1990)

Anti-Saccharomyces cerevisiae antibodies (ASCA), phenotypes of IBD, and intestinal permeability: a study in IBD families

BACKGROUND

Serologic markers anti-Saccharomyces cerevisiae antibodies (ASCA) and antineutrophil cytoplasmic antibodies with perinuclear staining (pANCA) have been proposed to study the immunopathogenesis of IBD. Their measurement may allow better phenotyping of the disease and the detection of subclinical disease.

AIMS

To test the hypothesis that serological markers identify an immunologic trait related to disease susceptibility. We also wanted to test the hypothesis that ASCA is a marker related to abnormal tissue permeation by common antigens.

METHODS

We studied the prevalence of pANCA and ASCA in a large cohort of sporadic and familial inflammatory bowel diseases and their unaffected relatives and spouses. Kinetics of ASCA was studied and the relationship between ASCA and 51Cr-EDTA intestinal permeation was investigated.

RESULTS

ASCA was associated with sporadic Crohn's disease (CD) (63%), with Crohn's patients belonging to pure CD families (62%) and also with their unaffected family members (21%). pANCA was associated with UC (58%). The prevalence of ASCA in CD patients belonging to mixed families was strikingly low (33%). ASCA was a stable marker throughout the disease and was not related to an increased small intestinal permeability.

CONCLUSION

ASCA is strongly associated with familial CD in Belgium, and 21% of healthy family members also display the marker. The association is much weaker in patients belonging to mixed families. ASCA is a stable marker and is not a secondary phenomenon due to increased intestinal permeability.

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.

Enhanced production of IL-8 in chronic but not in early ileal lesions of Crohn's disease (CD)

Distinct Th1/Th2 patterns have been observed during the evolution of CD. The aim of this study was to compare neutrophil involvement and IL-8 mRNA and protein expression during early recurrent lesions and chronic phases of CD. Twenty-nine patients with CD having ileocolonic resection with anastomosis were studied. Biopsies were obtained during surgery from the non-inflamed ileal mucosa and from chronic ileal lesions. Endoscopic ileal biopsies were also taken from early recurrent ileal lesions occurring 3 months after surgery. Neutrophil counts were performed and mucosal IL-8 levels were evaluated by competitive reverse transcriptase-polymerase chain reaction and immunohistochemistry. Early recurrent ileal lesions were characterized by low neutrophil counts and IL-8 production at the mRNA and protein levels compared with the ileal chronic lesions. The main cellular sources of IL-8 in the early recurrent lesions were neutrophils, while in chronic lesions the majority of IL-8-stained cells were CD3+ T cells and macrophages. These results confirmed that the nature of the inflammatory infiltrate and the expression of cytokine profiles may differ between the acute and chronic phases of CD.

Exclusion of linkage of Crohn's disease to previously reported regions on chromosomes 12, 7, and 3 in the Belgian population indicates genetic heterogeneity

Susceptibility to inflammatory bowel disease (IBD) is significantly determined by genetic factors. Linkage data from genome-wide searches have identified regions on chromosomes 16, 12, 7, and 3. Our goal was to replicate these four regions in a Belgian population of IBD families. Fifty-four IBD families were studied (47 with Crohn's disease [CD] and 7 with mixed CD and ulcerative colitis, containing 79 affected sibpairs (68 CD only, 11 mixed) for the regions previously implicated to chromosomes 16, 12, 7, and 3. In this study, no evidence for linkage was found on any of the four chromosomal regions studied for either the whole IBD dataset or the CD subgroup. The multipoint maximum logarithm of odds scores were less than 0.7 for all four regions. Exclusion mapping could significantly exclude chromosomes 3, 7, and 12. Despite earlier findings, we could significantly exclude linkage of CD with previously reported regions on chromosomes 12, 7, and 3, and could not find evidence for linkage to chromosome 16. It is important to report these findings in light of the genetic heterogeneity of IBD. A genome-wide search on a larger group of affected siblings is being analyzed to detect other possible susceptibility loci in the Belgian population.

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.

Inflammatory bowel disease in children and adolescents in Sweden, 1984-1995

BACKGROUND

A prospective study of inflammatory bowel disease (IBD) in Sweden was performed to investigate whether the incidence and morbidity have changed from 1984 through 1995.

METHODS

Children 15 years of age or less with IBD were included--i.e., those with a definite diagnosis of ulcerative colitis (UC) and Crohn's disease (CD) and those classified as having indeterminate colitis (IC) and probable Crohn's disease (PCD). The study covered 56.5% of the pediatric population of Sweden.

RESULTS

The diagnosis of IBD was made in 639 children, which corresponds to a mean annual incidence of 5.8 per 100,000. The incidence increased from 4.6 per 100,000 per year from 1984 through 1986 to 7.0 from 1993 through 1995. It reflected an increase in UC from 1.4 to 3.2 per 100,000 per year, which is a significant yearly percentage of increase (8%; confidence interval, 2-14%; P < 0.05). In contrast, no change occurred in the incidence of CD (1.2-1.3 per 100,000). The incidence of IC and PCD also remained fairly stable. The percentages of children who underwent surgery decreased from 17.3% in the first 6 years to 4.6% in the last 6 years (P < 0.001). Surgery was performed in 27.7% of CD and 5.3% of UC cases. The median age at diagnosis was 12.2 years for UC, 13.0 years for CD, 11.2 for IC, and 11.2 for PCD. At diagnosis, 48 children (7.5%) were 5 years of age or less, whereas most of the patients were 11 years of age or more (398 children, 62.3%).

CONCLUSIONS

In Sweden, the incidence of UC has increased, whereas that of CD remains the same. A significant number of children were classified with IC and PCD. In most children, IBD was diagnosed when they were 11 years old or more, but some cases were detected even in those below 6 years of age. A decrease in the frequency of surgery occurred during the study.

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.

The natural history of ulcerative proctitis: a multicenter, retrospective study. Gruppo di Studio per le Malattie Infiammatorie Intestinali (GSMII)

OBJECTIVE

The aim of this study was to evaluate the clinical features and the long term evolution of patients with a well defined initial diagnosis of ulcerative proctitis.

METHODS

Patients with an original diagnosis of ulcerative proctitis who had been seen at any of 13 institutions from 1989 to 1994 were identified. Data on disease onset and subsequent evolution were recorded. In addition, 575 patients with more extensive disease, treated in the same centers, were used as controls.

RESULTS

A total of 341 patients satisfied the inclusion criteria. The percentage of smokers in these patients was slightly lower than in controls; no differences were found in the other clinical/demographic variables evaluated. A total of 273 patients entered long term follow-up (mean, 52 months). Proximal extension of the disease occurred in 74 of them (27.1%). The cumulative rate of proximal extension and of extension beyond the splenic flexure was 20% and 4% at 5 yr and 54% and 10% at 10 yr, respectively. The risk of proximal extension was higher in nonsmokers, in patients with >3 relapses/yr, and in patients needing systemic steroid or immunosuppressive treatment. Refractory disease was confirmed as an independent prognostic factor at multivariate analysis.

CONCLUSIONS

Proximal extension of ulcerative proctitis is frequent and may occur even late after the original diagnosis. However, the risk of extension beyond the splenic flexure appears to be quite low. Smoking seems to be a protective factor against proximal extension, whereas refractoriness is a risk factor for proximal extension of the disease.

Inflammatory alterations in mesenteric adipose tissue in Crohn's disease

BACKGROUND & AIMS

Abnormalities of fat in the mesentery including adipose tissue hypertrophy and fat wrapping have been long recognized on surgical specimens as characteristic features of Crohn's disease. However, the importance, origin, and significance of the mesenteric fat hypertrophy in this chronic inflammatory disease are unknown. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a crucial factor involved in the homeostasis of adipose tissue, a major source of biologically active mediators.

METHODS

Intra-abdominal fat accumulation was quantified using a magnetic resonance imaging method in patients with Crohn's disease and controls. PPARgamma and inflammatory cytokines synthesized by mesenteric adipose tissues were assessed by quantitative polymerase chain reaction, in situ hybridization, and immunohistochemistry.

RESULTS

In vivo, patients with Crohn's disease have an important accumulation of intra-abdominal fat. This mesenteric obesity, present from the onset of the disease, is associated with overexpression of PPARgamma and tumor necrosis factor (TNF)-alpha, synthesized, at least in part, by adipocytes.

CONCLUSIONS

These results suggest that confined increased PPARgamma mesenteric concentrations could lead to the mesenteric fat hypertrophy, which could actively participate through the synthesis of TNF-alpha in the inflammatory response.

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.

Abnormalities in mucin gene expression in Crohn's disease

Alterations in the structure and/or quantity of mucins could alter the barrier function of mucus and play a role in initiating and maintaining mucosal inflammation in Crohn's disease. To investigate the hypothesis of a mucin gene defect in Crohn's disease, we analyzed the expression of the different mucin genes in the ileal mucosa of patients with Crohn's disease and controls. mRNA expression levels were assessed by a quantitative dot blot analysis and compared (i) between healthy and involved ileal mucosa of patients with Crohn's disease and (ii) between healthy mucosa of patients with Crohn's disease and controls. Expression of the different mucin genes was heterogeneous among controls and patients with Crohn's disease, except for MUC6 in controls. Nevertheless, MUC1 mRNA expression was significantly decreased in the involved ileal mucosa of patients with Crohn's disease when compared to the healthy mucosa (p = 0.02). Moreover, the expression levels of MUC3, MUC4, and MUC5B were significantly lower in both healthy and involved ileal mucosa of patients with Crohn's disease compared to controls (p < or = 0.05). The decrease of expression levels of some mucin genes (more particularly MUC3, MUC4, and MUC5B) in both healthy and involved ileal mucosa suggests a primary or very early mucosal defect of these genes in CD.

Abnormalities in mucin gene expression in Crohn's disease

Alterations in the structure and/or quantity of mucins could alter the barrier function of mucus and play a role in initiating and maintaining mucosal inflammation in Crohn's disease. To investigate the hypothesis of a mucin gene defect in Crohn's disease, we analyzed the expression of the different mucin genes in the ileal mucosa of patients with Crohn's disease and controls. mRNA expression levels were assessed by a quantitative dot blot analysis and compared (i) between healthy and involved ileal mucosa of patients with Crohn's disease and (ii) between healthy mucosa of patients with Crohn's disease and controls. Expression of the different mucin genes was heterogeneous among controls and patients with Crohn's disease, except for MUC6 in controls. Nevertheless, MUC1 mRNA expression was significantly decreased in the involved ileal mucosa of patients with Crohn's disease when compared to the healthy mucosa (p = 0.02). Moreover, the expression levels of MUC3, MUC4, and MUC5B were significantly lower in both healthy and involved ileal mucosa of patients with Crohn's disease compared to controls (p < or = 0.05). The decrease of expression levels of some mucin genes (more particularly MUC3, MUC4, and MUC5B) in both healthy and involved ileal mucosa suggests a primary or very early mucosal defect of these genes in CD.

Presence of adherent Escherichia coli strains in ileal mucosa of patients with Crohn's disease

BACKGROUND & AIMS

Infectious agents are suspected of being involved in the pathogenesis of Crohn's disease. This study was designed to look for the presence of virulent Escherichia coli strains associated with the ileal mucosa of patients with Crohn's disease.

METHODS

E. coli strains were recovered from resected chronic ileal lesions (n = 20), neoterminal ileum after surgery from patients with (n = 19) and without (n = 11) endoscopic recurrence, and controls (n = 13). Bacterial adhesion was determined in vitro using intestinal cell lines; other associated virulence factors were assessed by DNA hybridization and polymerase chain reaction experiments.

RESULTS

None of the strains harbored any of the virulence factor-encoding genes of E. coli involved in acute enteric diseases. However, mannose-resistant adhesion to differentiated Caco-2 cells was found for 84.6% and 78.9% of the E. coli strains isolated from chronic and early recurrent lesions, respectively, compared with 33% of controls (P < 0.02). In addition, 21.8% of the strains induced a cytolytic effect by synthesis of an alpha-hemolysin.

CONCLUSIONS

E. coli strains isolated from the ileal mucosa of patients with Crohn's disease adhere to differentiated intestinal cells and may disrupt the intestinal barrier by synthesizing an alpha-hemolysin.

American families with Crohn's disease have strong evidence for linkage to chromosome 16 but not chromosome 12

BACKGROUND & AIMS

Two European genome-wide screens for inflammatory bowel disease have identified two significant regions of linkage on chromosomes 16 (IBD1) and 12 (IBD2) and two regions with suggestive levels of significance (chromosomes 3p and 7q). The aim of this study was to determine if there was evidence for linkage to these regions in non-Jewish and Ashkenazi Jewish families multiplex for Crohn's disease from the United States.

METHODS

One hundred forty-eight affected relative pairs, 34% Ashkenazim, were genotyped with 10-14 highly polymorphic markers overlying each candidate region. Nonparametric multipoint and two-point linkage analyses were performed.

RESULTS

Significant evidence for replication of linkage was found only for the chromosome 16 locus, IBD1, maximal at D16S769 (nonparametric linkage score [NPL], 2.49; P = 0.007). Analysis by ethnicity showed stronger evidence for Ashkenazim (D16S769; NPL = 2. 52; P = 0.007) than for non-Jewish white populations (D16S401; NPL = 1.40; P = 0.082). There was no significant evidence for replication on chromosome 12 (IBD2). Minimal evidence for extension of linkage evidence was observed for the chromosomes 3p and 7q regions.

CONCLUSIONS

American families, particularly Ashkenazim, have significant evidence for the Crohn's disease susceptibility locus, IBD1, on chromosome 16, but not for IBD2 on chromosome 12.

Anti-Saccharomyces cerevisiae mannan antibodies in familial Crohn's disease

OBJECTIVE

Anti-Saccharomyces cerevisiae mannan antibodies (ASCA) are associated with Crohn's disease. The aim of this study was to determine the prevalence of ASCA in families in which at least two members were affected with Crohn's disease.

METHODS

A total of 20 families including two (n=15) or more (n=5) patients with Crohn's disease were tested for ASCA with use of an ELISA method. Overall, 51 affected members, 66 healthy first degree relatives, and 163 healthy control subjects were studied.

RESULTS

ASCA were detected in 35 of 51 (69%) patients with Crohn's disease and in 13 of 66 (20%) healthy relatives versus one of 163 healthy control subjects (p < 0.0001 and p < 0.001). ASCA-positive relatives were distributed in 12 of 20 families. ASCA were present in eight healthy parents and four healthy siblings. The prevalence of ASCA in relatives did not depend on the ASCA status of affected members.

CONCLUSION

ASCA in 20% of healthy first degree relatives of patients with Crohn's disease suggest that these antibodies might be a subclinical marker for Crohn's disease in families. Whether ASCA reflect environmental or genetic factors or a combination of both is unknown.

Identification of novel susceptibility loci for inflammatory bowel disease on chromosomes 1p, 3q, and 4q: evidence for epistasis between 1p and IBD1

The idiopathic inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), are chronic, frequently disabling diseases of the intestines. Segregation analyses, twin concordance, and ethnic differences in familial risks have established that CD and UC are complex, non-Mendelian, related genetic disorders. We performed a genome-wide screen using 377 autosomal markers, on 297 CD, UC, or mixed relative pairs from 174 families, 37% Ashkenazim. We observed evidence for linkage at 3q for all families (multipoint logarithm of the odds score (MLod) = 2.29, P = 5.7 x 10(-4)), with greatest significance for non-Ashkenazim Caucasians (MLod = 3.39, P = 3.92 x 10(-5)), and at chromosome 1p (MLod = 2.65, P = 2.4 x 10(-4)) for all families. In a limited subset of mixed families (containing one member with CD and another with UC), evidence for linkage was observed on chromosome 4q (MLod = 2.76, P = 1.9 x 10(-4)), especially among Ashkenazim. There was confirmatory evidence for a CD locus, overlapping IBD1, in the pericentromeric region of chromosome 16 (MLod = 1.69, P = 2.6 x 10(-3)), particularly among Ashkenazim (MLod = 1.51, P = 7.8 x 10(-3)); however, positive MLod scores were observed over a very broad region of chromosome 16. Furthermore, evidence for epistasis between IBD1 and chromosome 1p was observed. Thirteen additional loci demonstrated nominal (MLod > 1.0, P < 0.016) evidence for linkage. This screen provides strong evidence that there are several major susceptibility loci contributing to the genetic risk for CD and UC.

Anti-Saccharomyces cerevisiae mannan antibodies combined with antineutrophil cytoplasmic autoantibodies in inflammatory bowel disease: prevalence and diagnostic role

BACKGROUND

Perinuclear antineutrophil cytoplasmic autoantibodies (pANCA) are a well recognised marker for ulcerative colitis. Antibodies to oligomannosidic epitopes of the yeast Saccharomyces cerevisiae (ASCA) are a new marker associated with Crohn's disease.

AIMS

To assess the value of detecting pANCA and/or ASCA for the diagnosis of ulcerative colitis and Crohn's disease.

METHODS

Serum samples were obtained from 100 patients with Crohn's disease, 101 patients with ulcerative colitis, 27 patients with other miscellaneous diarrhoeal illnesses, and 163 healthy controls. Determination of pANCA and ASCA was performed using the standardised indirect immunofluorescence technique and an ELISA, respectively.

RESULTS

The combination of a positive pANCA test and a negative ASCA test yielded a sensitivity, specificity, and positive predictive value of 57%, 97%, and 92.5% respectively for ulcerative colitis. The combination of a positive ASCA test and a negative pANCA test yielded a sensitivity, specificity, and positive predictive value of 49%, 97%, and 96% respectively for Crohn's disease. Among patients with miscellaneous non-inflammatory bowel disorders, three were ASCA positive and two were pANCA positive. One control was ASCA positive. The presence of ASCA in patients with Crohn's disease was associated with small bowel involvement.

CONCLUSION

ASCA and pANCA are strongly associated with Crohn's disease and ulcerative colitis, respectively. Combination of both tests could help the diagnosis of inflammatory bowel disease.

Anticipation in familial Crohn's disease

BACKGROUND

Offspring with a family history of Crohn's disease have an earlier age of onset than their parents. This might be due to genetic anticipation, characterised by earlier and/or more severe disease in subsequent generations.

AIMS

To investigate the possibility of genetic anticipation in affected parent-child pairs with Crohn's disease from France and Belgium.

PATIENTS AND METHODS

In a cohort of 160 multiply affected families with Crohn's disease, 57 parent-first affected child pairs were detected. Clinical characteristics (age at diagnosis, disease extent, and type) of both parents and children were registered and compared.

RESULTS

Children were younger than their parents at diagnosis in 48/57 (84%) pairs. The median age at diagnosis was 16 years younger in children than in parents (p < 0.0001). However, the difference was related to the age at diagnosis in the parents and was not present in 12 parent-child pairs with an early age at diagnosis for the parents. In most cases, disease extent and type were not considered more severe in children than in parents. Parental sex affected neither age at diagnosis nor extent and type of disease in children.

CONCLUSION

Patients in the second affected generation acquire their disease at an earlier time in life in some but not all familial cases of Crohn's disease. Several explanations including genetic anticipation and environmental factors might explain this phenomenon.

High incidence of inflammatory bowel disease in The Netherlands: results of a prospective study. The South Limburg IBD Study Group

PURPOSE

To gain recent epidemiologic information about inflammatory bowel disease in The Netherlands, a prospective study over four years (1991-1995) was performed.

METHODS

The incidence of inflammatory bowel disease and its subgroups was examined using standardized reports of newly diagnosed patients. A separate study compared the Inflammatory Bowel Disease Registration and computerized diagnostic files of a subgroup of general practitioners with the aim of estimating completeness of case ascertainment.

RESULTS

The following mean incidence rates (per 100,000 inhabitants and year) were found: 6.9 (95 percent confidence interval, 5.9-7.9) for Crohn's disease, 10 (95 percent confidence interval, 8.7-11.2) for ulcerative colitis (23 percent of these with ulcerative proctitis), and 1.1 (95 percent confidence interval, 0.7-1.5) for indeterminate colitis. In the age category 20 to 29 years, the incidence rate of Crohn's disease with small-bowel involvement was higher in females than in males. In extended ulcerative colitis, a male preponderance was observed in the older age groups. Estimated case ascertainment was 78 percent.

CONCLUSIONS

Compared with recent studies in neighboring countries, the observed age and gender standardized incidence rates are high in the south of The Netherlands. Completeness of case ascertainment might have contributed to this observation; however, case ascertainment was low in ulcerative proctitis. In the study area, differences in age and gender standardized incidence rates and in disease localizations could be compatible with an influence of environmental risk factors.

Immunoglobulin G subclass distribution of anti-endothelial cell antibodies (AECA) in patients with ulcerative colitis or Crohn's disease

Anti-endothelial cell antibodies have been described in sera from patients with inflammatory bowel disease. The aim of this study was to determine, by ELISA, the IgG subclass distribution of anti-endothelial cell antibodies, in patients with ulcerative colitis (N = 28) or Crohn's disease (N = 82) as compared with blood donors (N = 95). Thirty-six percent of ulcerative colitis and 23% of Crohn's disease patients were positive for at least one of the IgG anti-endothelial cell subclasses. Interestingly, the pattern of IgG anti-endothelial cell subclass observed in the two inflammatory bowel diseases differs. In Crohn's disease, the IgG1 anti-endothelial cell antibody level was significantly increased (P < 0.05) while IgG2 and IgG4 anti-endothelial cell antibody levels were decreased (P < 0.0001 and P < 0.01, respectively) as compared to ulcerative colitis patients. The immunoglobulin G3 anti-endothelial cell antibody level was decreased in both ulcerative colitis and Crohn's disease patients as compared to healthy blood donors. No relationship was detected between disease activity of ulcerative colitis or Crohn's disease patients and anti-endothelial cell IgG subclasses. Finally, the disparity of IgG anti-endothelial cell subclass distribution in these two inflammatory bowel diseases suggests that the ability to activate effector mechanisms is not identical, and hence, deals with the concept of distinctive pathogenetic mechanisms in these two diseases.

Incidence of Crohn's disease in Stockholm County 1955-1989

AIM

To evaluate the incidence of Crohn's disease in Stockholm County between 1955 and 1989.

METHODS

A cohort of 1936 patients with Crohn's disease was retrospectively assembled. Incidence rates and changes in disease distribution were assessed.

RESULTS

The mean increase in incidence was 15% (95% confidence intervals 12% to 18%) per five year period with a mean annual incidence rate at 4.6/10(5) during the last two decades. The mean incidence for the entire study period was similar for men and women. The mean age at diagnosis increased from 25 years in 1960-64 to 32 years in 1985-89, partly because of an increasing proportion of patients aged at least 60 years at diagnosis. The proportion of patients with colonic Crohn's disease at the time of diagnosis increased from 15% to 32% (17% difference; 95% confidence intervals 12% to 23%) whereas the proportion of patients with ileocaecal disease decreased from 58% to 41% (17% difference; 95% confidence intervals 10% to 24%) during the study period. Elderly patients had a higher proportion of small bowel disease and a lower proportion of ileocolonic disease compared with the younger patients.

CONCLUSION

The incidence rate of Crohn's disease in Stockholm has stabilised at 4.6/10(5) and the proportion of elderly patients has increased during a 35 year period. Colonic Crohn's disease has increased in frequency with a reciprocal decrease in ileocaecal disease.

The role of Peyer's patches in the age-related incidence of Crohn's disease

Recently researchers have suggested that clinical subsets of Crohn's disease occur, which are variously described as inflammatory, fibrostenotic, and fistulizing. In addition, it has been observed that within families with multiple cases, often there is concordance of the site and type of disease. The lesions of Crohn's disease occur in segments that suggest that distribution of Peyer's patches. When the age-related incidence of Crohn's disease was plotted for all countries from which such data were available, the peaks of greatest case frequency occurred at ages 15 to 25 years and paralleled a similar peak representing the number of Peyer's patches as a function of age. This correlation suggests that Crohn's disease may develop as an inflammatory process specifically targeting these important lymphoid structures. Similar peaks of activity in the adolescent to early adult years occur for appendicitis and tonsillitis.

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)

BACKGROUND

It has been suggested that the incidence of inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is three or more times higher in northern than in southern Europe. The aim of this EC funded study was to investigate this apparent variation by ascertaining the incidence of IBD across Europe.

METHODS

For the period 1 October 1991 to 30 September 1993 all new patients diagnosed with IBD were prospectively identified in 20 European centres according to a standard protocol for case ascertainment and definition.

FINDINGS

Altogether 2201 patients aged 15 years or more were identified, of whom 1379 were diagnosed as UC (including proctitis), 706 as CD, and 116 as indeterminate. The overall incidence per 100,000 at ages 15-64 years (standardised for age and sex) of UC was 10.4 (95% confidence interval (95% CI) 7.6 to 13.1) and that of CD was 5.6 (95% CI 2.8 to 8.3). Rates of UC in northern centres were 40% higher than those in the south (rate ratio (RR) = 1.4 (95% CI 1.2 to 1.5)) and for CD they were 80% higher (RR = 1.8 (95% CI 1.5 to 2.1)). For UC the highest reported incidence was in Iceland (24.5, 95% CI 17.4 to 31.5) and for CD, Maastricht (The Netherlands; 9.2, 95% CI 6.5 to 11.8) and Amiens (north west France; 9.2, 95% CI 6.3 to 12.2). The lowest incidence of UC was in Almada (southern Portugal) (1.6, 95% CI 0.0 to 3.2) and of CD in Ioannina (north west Greece) (0.9, 95% CI 0.0 to 2.2). An unexpected finding was a difference in the age specific incidence of UC in men and women with the incidence in women but not men declining with age.

INTERPRETATION

The higher overall incidence rates in northern centres did not seem to be explained by differences in tobacco consumption or education. Nevertheless, the magnitude of the observed excess for both conditions is less than expected on the basis of previous studies. This may reflect recent increases in the incidence of IBD in southern Europe whereas those in the north may have stabilised.

A population-based study of inflammatory bowel disease in Florence over 15 years (1978-92)

BACKGROUND

In the group of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD) are considered to be more frequent in Western countries and in areas with a high socioeconomic development but relatively infrequent in southern Europe. Sporadic reports have indicated a lower incidence and a milder course of the disease in Mediterranean countries. Although conclusive data on this point are still lacking, recent reports suggest an increase in both incidence and prevalence rates.

METHODS

The incidence of UC and CD during the period January 1978 to December 1992 and their prevalence on 31 December 1992 were estimated in the 15-year-old population of the metropolitan area of Florence. Clinical, demographic, and follow-up information was collected for all identified IBD patients.

RESULTS

A total of 796 residents (345 females and 454 males) were newly diagnosed as having IBD during the study period. Of these 593 had UC and 203 CD. The age-standardized incidence rates, calculated for each of five 3-year consecutive periods, rose from 3.8 (in 1978-80) to 9.6 per 100,000 person-years (in 1990-92) for UC and from 1.9 (in 1978-80) to 3.4 (in 1990-92) for CD. Both trends were statistically significant. The prevalence estimated on 31 December 1992 was 121.0 and 40.0 per 100,000 inhabitants for UC and CD, respectively.

CONCLUSIONS

Our results confirm that IBD incidence rates and prevalence in this area of central Italy are currently comparable with those reported in northern Europe. These data are necessary for planning adequate health care services for IBD patients.

Association of HLA class II genes with susceptibility to Crohn's disease

BACKGROUND

Published studies on the association between HLA class II genes and inflammatory bowel disease are contradictory perhaps because of the limited size and ethnic heterogeneity of the populations studied.

AIM

To compare the frequencies of HLA class II genes in a large number of French patients with Crohn's disease and in an ethnically matched control group.

METHODS

344 patients (196 F, 148 M, mean age 23.6 years) with Crohn's disease were molecularly genotyped for the HLA-DQB1 and DRB1 alleles. The results were compared with those for an ethnically matched control population of 488 white adults.

RESULTS

There were two significant variations of alleles at the DQB1 locus: an increase in DQB1*0501 allele frequency (chi 2 = 10.6, corrected p value (pc) = 0.01, odds ratio (OR) = 1.61) and a decrease in DQB1*0602/0603 allele frequencies (chi 2 = 8.43, pc = 0.037, OR = 0.66). DRB1 analysis showed associations with three allelic variations: an increase in the frequencies of DRB1*01 (chi 2 = 12.86, pc = 0.003, OR = 1.75) and DRB1*07 alleles (chi 2 = 11.18, pc = 0.008, OR = 1.58) and a very significant decrease in that of the DRB1*03 allele (chi 2 = 19.7, pc = 9.10(-5), OR = 0.46).

CONCLUSION

The alleles DRB1*01 and DRB1*07 are associated with susceptibility to Crohn's disease. The strong negative association between the DRB1*03 allele and Crohn's disease suggests that the HLA-DRB1*03 allele mediates 'resistance' to Crohn's disease.

A prospective epidemiologic study of Crohn's disease in Heraklion, Crete. Incidence over a 5-year period

BACKGROUND

There has been an impression from published work that Crohn's disease is less common in southern than in northern Europe. A low incidence of Crohn's disease has been observed in Greece, but conclusive data are still lacking.

METHOD

A 5-year prospective and population-based epidemiologic study of Crohn's disease was carried out in a well-defined area of Crete.

RESULTS

The mean annual incidence of the disease for the years 1990-94 was 3.0 per 10(5) inhabitants. During the study period the incidence increased from 1.9/10(5) in 1990 to 3.8/10(5) in 1994. The male to female ratio was 2.4:1. The age group 25-34 years had the highest age-adjusted incidence (6.3/10(5)). The incidence of Crohn's disease was also found to be higher in smokers, in urban areas, and in people with high educational level.

CONCLUSION

Crohn's disease is common in Heraklion, Crete. The findings of the study are discussed in relation to those of other European countries.

Epidemiology of inflammatory bowel disease: an update

What have epidemiologic studies on IBD taught so far? Consistent findings are as follows: A high incidence of both CD and UC in industrialized countries and an increase in these areas of the incidence of CD during the years 1960-80 followed by a plateau phase, and a more stable pattern in UC during the same period have been found. A greater number of mild cases have probably been diagnosed recently. This also helps to explain the differences in severity and survival between community and referral centre groups. The male to female ratio is greater than 1 in UC, and this is the opposite in CD. Mortality of IBD has decreased during the past decades. As young people are especially prone to develop IBD, most of those affected will have their disease for many years. In developing IBD, genetic influences are of importance. However, epidemiologic studies strongly point to possible interactions between genetically determined features and environmental or other factors. Of these exogenic factors smoking is the most consistent, being of negative influence in CD and protective in UC. Diet and oral contraceptives may influence disease expression, and perinatal events such as viral infections may alter adult susceptibility. The question remains open whether UC and CD are one diseases entity. Similarities in the epidemiologic features of UC and CD support the idea of IBD being one disease. Other findings suggest dividing UC and CD into further subgroups: in CD it has been suggested that fibrostenotic, penetrating, and inflammatory behaviour should be considered different disease entities; in UC some groups consider ulcerative proctitis a disease entity on its own, separating it from the proximally extending colitis. In therapeutic trials this approach has proved to be of importance, and it is not inconceivable that in subgroups, with regard to aetiopathogenetic mechanisms, different factors have to be looked for.

Mapping of a susceptibility locus for Crohn's disease on chromosome 16

Crohn's disease (CD) and ulcerative colitis are the major forms of chronic inflammatory bowel diseases in the western world, and occur in young adults with an estimated prevalence of more than one per thousand inhabitants. The causes of inflammatory bowel diseases remain unknown, but genetic epidemiology studies suggest that inherited factors may contribute in part to variation in individual susceptibility to Crohn's disease. A genome-wide search performed on two consecutive and independent panels of families with multiple affected members, using a non-parametric two-point sibling-pair linkage method, identified a putative CD-susceptibility locus on chromosome 16 (P less than 0.01 for each panel). The localization was centered around loci D16S409 and D16S419 by using multipoint sibpair analysis (P less than 1.5x10(-5)). This region of the genome contains candidate genes which may be relevant to the pathogenic mechanism of inflammatory bowel diseases.