Prevalence and incidence of inflammatory bowel disease in family members

Fullerene nanoparticles for the treatment of ulcerative colitis

Ulcerative colitis (UC) is a long-term, recurrent inflammatory bowel disease for which no effective cure is yet available in the clinical setting. Repairing the barrier dysfunction of the colon and reducing intestinal inflammation are considered key objectives to cure UC. Here we demonstrate a novel therapeutic strategy based on a C₆₀ fullerene suspension (C₆₀FS) to treat dinitrobenzene sulfonic acid-induced UC in an animal model. C₆₀FS can repair the barrier dysfunction of UC and effectively promote the healing of ulcers; it also manifests better treatment effects compared with mesalazine enema. C₆₀FS can reduce the numbers of basophils in the blood of UC rats and mast cells in the colorectal tissue, thereby effectively alleviating inflammation. The expression of H1R, H4R, and VEGFR2 receptors in colorectal tissues is inhibited by C₆₀FS, and the levels of histamine and prostaglandin in the rat blood are reduced. This work presents a reliable strategy based on fullerene to cure UC and provides a novel guide for UC treatment.

Host Genetic and Gut Microbial Signatures in Familial Inflammatory Bowel Disease

INTRODUCTION:

The family history of inflammatory bowel disease (IBD) has been strongly associated with risk of developing IBD. This study aimed to identify the host genetic and gut microbial signatures in familial IBD.

METHODS:

Genetic analyses using genome-wide single nucleotide polymorphism genotyping and whole exome sequencing were performed to calculate weighted genetic risk scores from known IBD-associated common variants and to identify rare deleterious protein-altering variants specific to patients with familial IBD in 8 Korean families that each included more than 2 affected first-degree relatives (FDRs) and their unaffected FDR(s). In parallel, gut microbial community was analyzed by 16S rRNA sequencing of stools from the sample individuals.

RESULTS:

The risk of familial IBD was not well explained by the genetic burden from common IBD-risk variants, suggesting the presence of family-shared genetic and environmental disease-risk factors. We identified 17 genes (AC113554.1, ACE, AKAP17A, AKAP9, ANK2, ASB16, ASIC3, DNPH1, DUS3L, FAM200A, FZD10, LAMA5, NUTM2F, PKN1, PRR26, WDR66, and ZC3H4) that each contained rare, potentially deleterious variants transmitted to the affected FDRs in multiple families. In addition, metagenomic analyses revealed significantly different diversity of gut microbiota and identified a number of differentially abundant taxa in affected FDRs, highlighting 22 novel familial disease-associated taxa with large abundance changes and the previously reported gut dysbiosis including low alpha diversity in IBD and 16 known IBD-specific taxa.

DISCUSSION:

This study identified familial IBD-associated rare deleterious variants and gut microbial dysbiosis in familial IBD.

Long-Term Follow-Up, Association between CARD15/NOD2 Polymorphisms, and Clinical Disease Behavior in Crohn's Disease Surgical Patients

Background

CARD15/NOD2 is the most significant genetic susceptibility in Crohn's disease (CD) even though a relationship between the different polymorphisms and clinical phenotype has not been described yet. The study is aimed at analyzing, in a group of CD patients undergoing surgery, the relationship between CARD15/NOD2 polymorphisms and the clinical CD behavior after a long-term follow-up, in order to identify potential clinical biomarkers of prognosis.

Methods

191 surgical CD patients were prospectively characterized both for the main single nucleotide polymorphisms of CARD15/NOD2 and for many other environmental risk factors connected with the severe disease form. After a mean follow-up of 7.3 years, the correlations between clinical features and CD natural history were analyzed.

Results

CARD15/NOD2 polymorphisms were significantly associated with younger age at diagnosis compared to wild type cases (p < 0.05). Moreover, patients carrying a 3020insC polymorphism presented a larger Δ between diagnosis and surgery (p = 0.0344). Patients carrying an hz881 and a 3020insC exhibited, respectively, a lower rate of responsiveness to azathioprine (p = 0.012), but no difference was found in biologic therapy. Finally, the risk of surgical recurrence was significantly associated, respectively, to age at diagnosis, to familial CD history, to diagnostic delay, to arthritis, and to the presence of perioperative complications.

Conclusions

3020insC CARD15 polymorphism is associated with an earlier CD onset, and age at CD diagnosis < 27 years was confirmed to have a detrimental effect on its clinical course. In addition, the familiarity seems to be connected with a more aggressive postoperative course. Finally, for the first time, we have observed a lower rate of responsiveness to azathioprine in patients carrying an hz881 and a 3020insC.

Change in Prevalence of Family History During Long-term Follow-up of Patients With Pediatric-onset Inflammatory Bowel Disease

OBJECTIVES

The aim of the study was to prospectively study changes in prevalence of positive family history (FH+) in pediatric-onset inflammatory bowel disease (IBD) in contrast to previously published cross-sectional data.

METHODS

An observational cohort study was performed using a prospective pediatric-onset IBD database including 485 patients with disease duration ≥10 years as of December 2016. Proband characteristics and FH+ were obtained at diagnosis and subsequently from the database, medical records, and follow-up telephone interviews in 2006 and 2016.

RESULTS

Updated 2016 information was obtained from 322 (66%) patients and included in analysis with median follow-up of 18 years (interquartile range 14, 26). Prevalence of FH+ increased from 13.7% at diagnosis to 26.6% at 20 years for first-degree relatives and from 38.5% to 52.2% for all relatives. At 20-year follow-up, an additional 10.0% of probands had a sibling, 6.1% had a parent, 1.9% had a grandparent, and 4.5% had a cousin diagnosed with IBD. FH+ at diagnosis was associated with greater risk for additional FH+ at 20 years (43% vs 22%, P < 0.001). Non-Jewish Caucasians had significantly lower risk of a FH+ compared to Jewish Caucasians (P = 0.002), but similar risk to African Americans (P = 0.55). FH+ at diagnosis was not associated with disease type (P = 0.33) or age at diagnosis (P = 0.24).

CONCLUSIONS

This prospective study documents changes in family history of IBD in pediatric-onset IBD patients over time. Prevalence of FH+ increased for first-degree and all relatives at 20 years by 12.9% and 13.7%, respectively. FH+ at diagnosis was associated with a 2-fold greater likelihood of subsequent FH+ at 20 years.

Stem cell transplant in inflammatory bowel disease: a promising modality of treatment for a complicated disease course

Inflammatory bowel disease (IBD) is a complex, relapsing and remitting, disease characterized by an exaggerated immune response in a susceptible host. The symptoms and complications of the disease can be debilitating. Advances in medical treatment in the last decade changed the course of the disease in many patients. Despite the use of novel agents for controlling disease, a proportion of patients' disease courses continue to be either refractory, or become resistant, to available therapeutic options. Stem-cell therapy, with hematopoietic stem cells (HSCs) or mesenchymal stem cells (MSCs), is a promising modality of treatment for severe refractory cases, mainly Crohn's disease (CD) patients. HSCs have the ability to migrate to damaged tissue, which provides them with further properties to differentiate to epithelial or immune-modulatory cells to restore normal mucosal tissue and integrity. MSCs therapy is a promising model for patients with perianal CD due to their immunosuppressive properties, ability to migrate to areas of injury, and demonstration of colonic healing, including fistulizing tracts. The results from ongoing clinical trials will provide a valuable understanding of the future of stem-cell therapy as a treatment option in refractory cases of IBD, a disease whose pathogenesis remains unknown, and is notoriously difficult to treat.

Familial and ethnic risk in inflammatory bowel disease

Familial aggregation in inflammatory bowel disease (IBD) has been established for several decades, reflecting shared genetic and environmental susceptibility. A positive family history remains the strongest recognizable risk factor for the development of IBD and is reported in around 8-12% of IBD patients. Crohn’s disease shows a more frequent familial pattern than ulcerative colitis. The risk of developing IBD in first-degree relatives of an affected proband is increased 4- to 8-fold. The risk for twins and children born from couples who both have IBD is also substantially higher; a cumulative effect of the number of family members affected has been described, with the highest incidence being described for families with three or more affected members. Herein, we review the available evidence regarding familial IBD, and briefly discuss the variation of IBD across different races and ethnicities, hoping to provide a useful update and a practical guide that can serve clinicians as a guide for counseling.

Review article: evidence-based dietary advice for patients with inflammatory bowel disease

BACKGROUND

The therapeutic effect of enteral nutrition in Crohn's disease (CD) and the epidemiological associations between diet and inflammatory bowel disease (IBD) implicate diet in IBD causation. There is little evidence, however, to support specific dietary changes and patients often receive contradictory advice.

AIM

To review the literature on the impacts of diet on IBD causation and activity to produce guidance based on 'best available evidence'.

METHOD

Review of Medline, Embase and Cochrane databases from 1975 to 2012 using MeSH headings 'crohn's disease' 'ulcerative colitis' 'enteral' 'diet' 'nutrition' 'fatty acid' and 'food additives'.

RESULTS

Enteral nutrition with a formula-defined feed is effective treatment for CD, but approximately 50% of patients relapse within 6 months of return to normal diet. There is no direct evidence of benefit from any other specific dietary modification in CD, but indirect evidence supports recommendation of a low intake of animal fat, insoluble fibre and processed fatty foods containing emulsifiers. Foods tolerated in sustained remission may not be tolerated following relapse. Some evidence supports vitamin D supplementation. In ulcerative colitis (UC), evidence is weaker, but high intakes of meat and margarine correlate with increased UC incidence and high meat intake also correlates with increased likelihood of relapse.

CONCLUSIONS

There is little evidence from interventional studies to support specific dietary recommendations. Nevertheless, people with IBD deserve advice based on 'best available evidence' rather than no advice at all, although dietary intake should not be inappropriately restrictive. Further interventional studies of dietary manipulation are urgently required.

Epigenetics: filling in the 'heritability gap' and identifying gene-environment interactions in ulcerative colitis

Ulcerative colitis is a common inflammatory bowel disorder associated with considerable morbidity. Its incidence is increasing worldwide. While familial aggregation of ulcerative colitis is a common phenomenon, genome-wide association studies, identifying a plethora of associated genes, have failed to reveal a unifying causative pathway. The well-documented impact of a number of environmental factors on disease occurrence and natural history suggests a major role for epigenetic events. The epigenome-wide association study discussed in this highlight has revealed novel loci linked to colitis and has provided unique insights into the pathophysiology of this disorder information that could translate into new therapeutic approaches.

Risk factors for repeat abdominal surgery in korean patients with Crohn's disease: a multi-center study of a korean inflammatory bowel disease study group

Purpose

The purpose of this study was to assess the risk factors for repeated abdominal surgery in Crohn's disease (CD) patients after the first abdominal surgery. Prior studies have tried to identify the risk factors for postoperative recurrence in CD patients, but the results of the studies have been inconsistent. Furthermore, few data on the risk factors for repeated abdominal surgery are available.

Methods

Clinical data on CD patients who underwent abdominal surgery from January 2000 to December 2009 were collected from seventeen university hospitals and one colorectal clinic. Data from a total of 708 patients were analyzed to find the risk factors for repeated abdominal surgery in CD patients. The mean follow-up period was 72 months.

Results

The risk of repeated abdominal surgery was 3 times higher in young patients (below 16 years old) than in older patients (odds ratio [OR], 3.056; 95% confidence interval [CI], 1.021 to 9.150); P = 0.046). Stricturing behavior at diagnosis was also a risk factor for repeated abdominal surgery (OR, 2.438; 95% CI, 1.144 to 5.196; P = 0.021). Among operative indications, only intra-abdominal abscess was associated with repeated abdominal surgery (OR, 2.393; 95% CI, 1.098 to 5.216; P = 0.028). Concerning type of operation, an ileostomy might be a risk factor for repeated abdominal surgery (OR, 11.437; 95% CI, 1.451 to 90.124; P = 0.021). Emergency surgery (OR, 4.994; 95% CI, 2.123 to 11.745; P < 0.001) and delayed diagnosis after surgery (OR, 2.339; 95% CI, 1.147 to 4.771; P = 0.019) also increased the risk of repeated abdominal surgery.

Conclusion

Young age (below 16 years), stricturing behavior, intra-abdominal abscess, emergency surgery, and delayed diagnosis after surgery were identified as possible risk factors for repeated abdominal surgery in CD patients.

Ulcerative colitis and Crohn's disease: is Mycobacterium avium subspecies paratuberculosis the common villain?

Mycobacterium avium, subspecies paratuberculosis (MAP) causes a chronic disease of the intestines in dairy cows and a wide range of other animals, including nonhuman primates, called Johne's ("Yo-knee's") disease. MAP has been consistently identified by a variety of techniques in humans with Crohn's disease. The research investigating the presence of MAP in patients with Crohn's disease has often identified MAP in the "negative" ulcerative colitis controls as well, suggesting that ulcerative colitis is also caused by MAP. Like other infectious diseases, dose, route of infection, age, sex and genes influence whether an individual infected with MAP develops ulcerative colitis or Crohn's disease. The apparently opposite role of smoking, increasing the risk of Crohn's disease while decreasing the risk of ulcerative colitis, is explained by a more careful review of the literature that reveals smoking causes an increase in both diseases but switches the phenotype from ulcerative colitis to Crohn's disease. MAP as the sole etiologic agent of both ulcerative colitis and Crohn's disease explains their common epidemiology, geographic distribution and familial and sporadic clusters, providing a unified hypothesis for the prevention and cure of the no longer "idiopathic" inflammatory bowel diseases.

Gastroenterologists' attitudes and self-reported practices regarding inflammatory bowel disease

BACKGROUND

The purpose was to assess organization-, physician-, and patient-based aspects of inflammatory bowel disease (IBD) practice variation within an integrated care delivery system and the extent to which physicians are interested in adopting a chronic care model and/or nurse assistance to manage IBD patients.

METHODS

As part of an observational cohort study to understand variation in IBD care and outcomes, we conducted semistructured, open-ended interviews with 17 gastroenterologists and 1 gastroenterology registered nurse at 6 clinics in an integrated care delivery system. Interviews were taperecorded and transcribed. We coded and analyzed transcripts using standard qualitative methods.

RESULTS

Physicians reported a range of attitudes and practices regarding IBD. Analysis showed differences in 3 domains and 8 subdomains: 1) patient education and choices, including health education and patient use of complementary and alternative medicine; 2) decisions about diagnosis and treatment, including practice guidelines, conferring with colleagues, using infliximab, and medical hospitalization; and 3) organizational aspects of care, including primary care involvement with IBD and MD attitudes toward ancillary support.

CONCLUSIONS

Standardized algorithms on care for IBD patients do not exist, but opportunities may exist to improve IBD care by: having initial work-ups and management of patients in remission in primary care; creating and maintaining opportunities for gastroenterologists to confer with colleagues and acknowledged local experts; and having nurse coordination for medications and labs and/or some type of specialty IBD clinic for high-need patients. This research highlights the need for more directed comparative efficacy and effectiveness trials that will serve to define preferred treatment strategies.

Familial occurrence of inflammatory bowel disease in Korea

BACKGROUND

Little information is available about the familial aggregation of inflammatory bowel disease (IBD) in Asian populations. We therefore determined the risk of familial aggregation of IBD among first-degree relatives of patients with ulcerative colitis (UC) or Crohn's disease (CD) in an ethnically distinct Korean population.

METHODS

Familial aggregation of IBD was evaluated in terms of family history, prevalence, lifetime risk, and population relative risk in first-degree relatives of 1440 unrelated patients with UC (n = 1043) or CD (n = 397).

RESULTS

A positive first-degree family history of IBD was observed in 27 probands (1.88%): 21 of 1043 (2.01%) with UC and 6 of 397 (1.51%) with CD. The crude prevalence of IBD in first-degree relatives of probands with IBD was 0.31%. The lifetime risk of IBD was 0.54% in all first-degree relatives of IBD probands, 0.52% in UC probands, and 0.67% in CD probands, with overall lifetime relative risks of 0.12% in parents, 0.79% in siblings, and 1.43% in offspring. The age- and sex-adjusted population relative risk of IBD was 13.8 in first-degree relatives of probands with IBD.

CONCLUSIONS

Although a positive family history, prevalence, and lifetime risk of IBD among first-degree relatives of Korean IBD patients are much lower than among relatives of Western patients, the population relative risk in first-degree relatives is about equal in Koreans and Westerners. This finding indicates that a positive family history is an important risk factor for IBD in Koreans and in Westerners.

Efficacy of granulocyte apheresis in pediatric patients with ulcerative colitis: a pilot study

OBJECTIVES

Granulocyte apheresis (GCAP), involving the removal of granulocytes from the blood, may improve clinical symptoms and facilitate a reduction in the dose of steroids in adult patients with ulcerative colitis. As a preliminary trial, GCAP was used to taper the dose of steroids in 4 pediatric patients with ulcerative colitis.

METHODS

Three males and 1 female ranging from 11 to 17 years old were treated with GCAP once per week for 5 consecutive weeks/course. The ages of patients at clinical onset ranged from 8 to 12 years and the length of time from the clinical onset to GCAP treatment ranged from 28 to 58 months (median, 38.5 months).

RESULTS

In 2 patients, symptoms and signs indicating disease activity improved after 2 courses of GCAP. Laboratory data and endoscopic findings also improved after treatment and the clinical efficacy was judged to be excellent in these patients. In 1 patient, GCAP improved laboratory and endoscopic hallmarks, but bloody stools persisted. Finally, the treatment was ineffective in the fourth patient who eventually underwent surgery.

CONCLUSIONS

GCAP is effective in improving clinical symptoms and may play an important role in converting steroid therapy to other treatments in children with steroid-refractory or steroid-dependent ulcerative colitis.

Advances in the molecular dissection of inflammatory bowel disease

Recent advances in the field of inflammatory bowel disease (IBD) genetics have enabled the definition and refinement of multiple IBD susceptibility loci and the identification of gene variants within such regions showing association with Crohn's disease (CD) and/or ulcerative colitis (UC). Most notable among the newly defined genetic determinants of IBD are specific variants in the CARD15 gene, which have been shown widely to influence both susceptibility and phenotype in CD. These genetic data have inspired intensive studies of CARD15 biologic functions and the information emerging from these analyses has already substantively enhanced understanding of the signaling pathways coupling bacterial pathogens to the host immune response. Genetic data implicating various other signaling effectors in IBD susceptibility have similarly focused attention on the molecular pathways driven or regulated by these proteins and the biochemical events linking effector/pathway dysfunction to intestinal inflammation and disease. In this review, progress in defining the genetic determinants of IBD is described with an emphasis on the impact of such knowledge on understanding of IBD molecular pathophysiology.

Crohn's disease runs a more aggressive course in young Asian patients

BACKGROUND

Crohn's disease is a heterogeneous inflammatory bowel disease. The impact of age at diagnosis on the clinical course of patients varies widely as reported in the Western literature. Using the Vienna Classification, we seek to determine whether young Crohn's disease patients in an Asian population followed a different clinical course than old patients.

METHODS

The case records of 100 Crohn's disease patients who were treated at the Inflammatory Bowel Disease Center, Singapore General Hospital, were studied retrospectively. The age group and location of disease and behavior according to the Vienna classification were determined at diagnosis.

RESULTS

A1 group (age <40 years) defined as "young" and A2 group (age > or =40) defined as "old" contained 65 and 35 patients, respectively. Median age for the young group was 27.4 years and that for the old group was 52.6 years. Of the young patients, 66.7% flared at least once compared with 28.6% of the old patients, odds ratio of 5.0 (P < 0.001). Young patients were more likely to be steroid dependent (20.0% of A1 versus 8.6% of A2, P = 0.14), received azathioprine (38.5% of A1 versus 5.7% of A2, P < 0.001) and experienced complications (31% of A1 versus 20% of A2, P = 0.25)-numerically higher rates that did not reach statistical significance. There was no significant difference between the age groups for the location and behavior of disease as well as requirement for surgery.

CONCLUSION

In this first Asian study looking specifically at the impact of age at diagnosis of Crohn's disease, we found that young patients underwent a more aggressive clinical course.

Inflammatory bowel disease: a complex group of genetic disorders

Inflammatory bowel disease (IBD) are complex genetic disorders resulting from the complex interplay between several genetic and environmental risk factors. The number of IBD genes is currently unknown but it is expected to be equal or higher to 8. None of these genes are expected to be neither necessary nor sufficient for disease development. Among the candidate genes investigated to date, only CARD15/NOD2 has been definitively associated with Crohn Disease (CD) but not Ulcerative Colitis (UC). This gene explains about 20% of the genetic predisposition to CD. Because it is involved in the innate immunity, it allows to speculate that CD is the result of a defect in host-bacteria interaction. However, it is not known if CD is caused by specific bacteria or the gut flora as a whole.

IBD: a family affair

The recent molecular advances in the understanding of the genetics of inflammatory bowel disease (IBD) have their grounding in studies examining IBD within different family groups and populations. The risk of IBD is highest in first-degree relatives of an IBD proband but more distant relatives are also at increased risk. The risk is higher for relatives of a CD proband. The risks of developing IBD for 'high-risk' relatives might be as great as 1 in 3 but in general first-degree relatives have a 1 in 10-20 risk. Three recent systematic studies have identified a total of 326 European twin pairs to examine disease concordance rates. The derived heritability in Crohn's disease is greater than for many complex diseases and is currently under detailed examination. Strong concordance has been shown, in particular for disease type and disease location, in multiplex families and twin studies. More than 75% children are diagnosed with IBD at a younger age than their parents but true genetic anticipation appears unlikely.

Clinical characteristics of familial versus sporadic Crohn's disease using the Vienna Classification

BACKGROUND

The etiology of Crohn's disease, an illness protean in its manifestations, may be better resolved through studies involving more homogenous subgroups of patients. Because a strong genetic influence exists, family history of inflammatory bowel disease may be a useful variable for patient classification if patients with familial and sporadic Crohn's disease are clinically different. Our study attempted to define any possible differences.

METHODS

The medical records of 552 patients were reviewed, and patients were classified according to guidelines of the Vienna Classification. Patients were then divided based on family history of inflammatory bowel disease, and the familial and sporadic groups were compared.

RESULTS

Overall, 422 (78.9%) patients were diagnosed before age 40 years (A1) and 114 (21.1%) at age 40 years or older (A2). There were 141 (26.3%) patients with disease involving the terminal ileum only (L1), 211 (39.4%) in the colon only (L2), 117 (21.9%) in the terminal ileum and colon (L3), and 66 (12.3%) in the upper gastrointestinal tract (L4). Disease behavior, as determined at the time of last visit or telephone contact, was nonstricturing, nonpenetrating (B1) in 149 (27.9%) patients, stricturing (B2) in 50 (9.3%) patients, and penetrating (B3) in 336 (62.8%) patients. Comparisons among the groups of 53 patients with first-degree relatives only, the 96 patients with either first-, second-, or third-degree relatives (familial CD group), and the 439 patients with sporadic disease demonstrated no differences in sex, age at diagnosis, or disease location. There was a difference in disease behavior between the familial and sporadic groups (p = 0.048) that failed to exist when nonstricturing, nonpenetrating cases were excluded. No such difference was observed between the first-degree relatives only group and the sporadic group (p > 0.10).

CONCLUSIONS

Using the Vienna Classification, familial and sporadic Crohn's disease differed only in disease behavior. However, this difference failed to exist after patients with nonstricturing, nonpenetrating disease were excluded. Therefore, familial and sporadic groups appear to be quite similar clinically, and family history does not appear to be a variable useful for disease subclassification.

Epidemiological features of ulcerative colitis in Trakya, Turkey

To determine the epidemiological features of ulcerative colitis in the Trakya region of Turkey, southeast Europe, we conducted a descriptive, cross-sectional, hospital-based study. All subjects were followed, and age, sex, place of residence, family history, educational status, tobacco consumption and use of oral contraceptives were recorded. The study included 49 cases of ulcerative colitis. The incidence of the disease was 0.59 per 100,000 in 1998, 0.89 per 100,000 in 1999, 0.89 per 100,000 in 2000 and 0.69 per 100,000 in 2001. The overall prevalence of the disease was 4.9 per 100,000; it was 2.18 per 100,000 in rural areas and 5.87 per 100,000 in urban areas. As in the Mediterranean countries, both the incidence and the prevalence of ulcerative colitis were found to be low. The incidence was significantly higher in urban areas than in rural areas.

Review article: monitoring the activity of Crohn's disease

Crohn's disease is characterized by a chronic inflammation of the intestine of unknown aetiology. One of the main problems when treating patients with Crohn's disease, is the identification of patients undergoing early clinical relapse, for timely treatment and the possible prevention of complications. No sub-clinical markers are currently available that predict relapse during remission. Several parameters have been proposed for this purpose. Although none have proven useful, growing evidence suggests a possible benefit in the clinical management of Crohn's disease. Among these, we may identify: clinical behaviour, the characteristics of the host, clinical activity, markers of intestinal inflammation and markers of immune activation. In particular, the possible relationship between cytokine pattern and the clinical behaviour of Crohn's disease has been addressed. Overall, these observations suggest that mucosal immune activation is a feature of Crohn's disease, and may persist in the form of activated immunocompetent cells during remission. On the basis of this evidence, studies are currently investigating whether the down-regulation of immune activation markers is associated with clinical remission in Crohn's disease. It has been shown that higher mucosal levels of TNF-alpha and an increased state of activation of lamina propria mononuclear cells in patients with inactive Crohn's disease, are significantly associated with an earlier clinical relapse of the disease. These observations suggest that a persistent local immune activation during remission may represent a marker of early clinical relapse of Crohn's disease.

The relationship between heritability and smoking habits in Crohn's disease. Italian Cooperative Study Group

OBJECTIVE

In Crohn's disease (CD), the relationship between genetic predisposition and smoking has not been well defined. The aim of this study was to compare the smoking habits at the time of the diagnosis of CD patients having familial occurrence of inflammatory bowel disease (IBD) with those of some control groups.

METHODS

In a multicenter study, 136 CD patients with a relative with IBD, 272 healthy controls matched for sex and age, 500 CD patients without familial occurrence of IBD, and 84 ulcerative colitis patients (UC) with familial occurrence of IBD were personally interviewed about their smoking habits. In addition, data for 35 healthy siblings of patients with familial CD were collected by interviewing the patients' relatives.

RESULTS

The prevalence of smokers was found significantly higher in CD patients with a family history for IBD than in healthy controls and in familial UC patients (OR 2.28 CI 1.5-3.48 and OR 5.81 CI 3.15-10.75, respectively). No significant difference was found either in the percentage of smokers or in the number of cigarettes smoked per day between familial and sporadic CD patients. Among all siblings of CD patients, 72% of affected siblings and 34% of healthy siblings were smokers, concordant with their relatives.

CONCLUSIONS

In CD patients with familial occurrence of IBD, the percentage of smokers is elevated. It is possible that in a genetically predisposed population, smoking could be an important environmental factor in determining CD or expressing this disease instead of UC.

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.

HLA class II alleles associated with susceptibility and resistance to Crohn's disease in the Jewish population

Previous studies have suggested that susceptibility to Crohn's disease (CD) is associated with the histocompatibility complex (HLA) class II alleles DR1, DQ5, and DR13 in the Caucasian population, DR7 in the French and German populations, and DR4 and DQ4 in the Japanese population. However, little is known about the relationship between HLA class II alleles and CD in the Jewish population since these previous studies included few Jewish individuals. In order to determine whether the HLA associations observed with predominantly non-Jewish populations were also present in the Jewish CD population and whether there were any HLA class II alleles uniquely associated with CD in the Jewish population, 132 CD patients, of which 82 were Ashkenazi Jewish, were HLA-typed using serologic and DNA methods. Ethnically matched controls were similarly typed. No association with DR1 or DR13 was observed in the Jewish CD population although an association with DR13 (OR [odds ratio] = 5.3, p = 0.02) was observed in the non-Jewish CD population. However, an association with DR15 (OR = 2.7, p = 0.03), which is normally associated with ulcerative colitis, was observed in the Jewish, but not non-Jewish, CD group. In addition, a strong negative association was observed with DR3, which was especially striking in the Jewish population (OR = 0.35, p = 0.025); similar negative associations with DR3 have been observed by others using non-Jewish populations. Furthermore, a significant negative association with DR7 (OR = 0.45, p = 0.04) was observed in the Jewish, but not non-Jewish, population. Consistent with this was the negative association with DQ2 (OR = 0.38, p = 0.005), which is in strong linkage disequilibrium with both DR3 and DR7, in the Jewish, but not non-Jewish, population. These studies support previous suggestions that susceptibility to CD in Jewish and non-Jewish populations is determined by distinct genes and provide further support to the hypothesis that a gene on the DR3 haplotype may protect against CD. Furthermore, protection is conferred by the same or another gene found on Jewish, but not non-Jewish, DR7 haplotypes.

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.

Prevalence and relative risk of malignancy in relatives of inflammatory bowel disease patients and control subjects

The relation between inflammatory bowel disease (IBD) and colorectal cancer (CRC) is not clearly defined. Some investigators suggest that patients with extensive colitis have a genetic predisposition to CRC and that long-standing inflammation is not of primary importance in the promotion of cancer. We have assessed any increased risk of colon cancer in the relatives of IBD patients. We studied the prevalence of malignancy in the relatives of 251 IBD patients [198 ulcerative colitis (UC); 53 Crohn's disease of the colon (CDC)] and 251 orthopedic patients (ORTHO) as controls. In all patients (UC, CDC) as well as in controls (ORTHO) the prevalence of colon, extracolic digestive and extradigestive malignant tumors in the first-degree relatives was evaluated. We found no significant difference in the number of colorectal tumors or of tumors of any other kind in the diverse group of relatives of patients with IBD and ORTHO patients. Our data do not point to the existence of hereditary factors linking UC or CDC to CRC.

[Initial symptoms, extra-intestinal manifestations and course of pregnancy in chronic inflammatory bowel diseases]

BACKGROUND

In many cases inflammatory bowel disease is accompanied by extraintestinal manifestations. This results in lowering of live quality. The aim of this study was to gather data retrospectively about initial symptoms, extraintestinal manifestations and course of pregnancy in a large unselected population with inflammatory bowel disease in South Germany.

PATIENTS AND METHODS

Data from 1975 to 1989 (392 patients) were analyzed and partially compared with data from 1992 to 1995 (211 patients).

RESULTS

Patients with Crohn's disease in average have been 25 years old at the time point of initial symptoms, whereas the age of ulcerative colitis patients was 30 years (p < 0.0001). The number of Crohn's disease patients with a long interval between initial symptoms and diagnosis (> 1 year) was significantly decreased in the second population (50% vs 38%; p < 0.05). Dominant initial symptoms in Crohn's disease were indisposition, abdominal pain and nonbloody diarrhea in contrast to ulcerative colitis which manifested mostly with bloody diarrhea. Extraintestinal manifestations occurred in 76% of patients with Crohn's disease and 64.6% with ulcerative colitis. Complications during the course of pregnancy have been detected in 40.5% in Crohn's disease and 60% in ulcerative colitis.

CONCLUSION

A better knowledge of initial symptoms and extraintestinal manifestations in inflammatory bowel disease can help to decrease the interval between initial symptoms and the diagnosis. Pregnancy in patients with inflammatory bowel disease needs to be treated with special care.

Familial aggregation of inflammatory bowel disease in a Mediterranean area

To evaluate familial aggregation of inflammatory bowel disease (IBD) in the Mediterranean area and to estimate the disease risk in first degree relatives. 427 patients with IBD were consecutively interviewed in order to obtain a complete pedigree of first degree relatives. Sufficient information was obtained in 98% of 2,685 family members. The prevalence ratio of IBD in family members was estimated and compared to the prevalence ratio of IBD in general population; the ratio was then standardized by age since the prevalence of the disease is age-dependent. The lifetime risk was assessed by the Kaplan Meier method. Thirty index cases (7%) had at least one affected first degree relative. As compared with the general population, first degree relatives of the 427 patients with IBD had a 4.38-fold increase in the age corrected risk of having the same disease. The kaplan-Meier curve showed a higher risk at 25 years of age for offsprings (3%) than for parents (1%) and siblings (1%) whereas the crude ratio showed a higher risk for siblings (1.9%) compared to parents (0.8%) and offsprings (1%). In the Mediterranean area, the familial prevalence of IBD is higher than in the general population and comparable to North European rates.

Preliminary evidence for genetic anticipation in Crohn's disease

BACKGROUND

The term genetic anticipation is used to describe earlier onset of disease, increased severity, or both, in succeeding generations of families affected by a particular disease. This process has been linked with expanded genomic trinucleotide repeat regions in some neurological disorders. Crohn's disease, an inflammatory bowel disorder, has genetic influences, which remain undefined. We studied pairs of two-generation first-degree relatives with Crohn's disease to seek evidence for genetic anticipation in this disorder.

METHODS

Through retrospective review of the records of 552 patients treated for Crohn's disease at Johns Hopkins Hospital, we identified 27 pairs of two-generation first-degree relatives. We also studied 32 such pairs identified through a multicentre survey. After exploratory analyses by t tests, a generalised estimating equations approach was used to fit a marginal regression model.

FINDINGS

The age at diagnosis was earlier in the younger member of the pair both in the Johns Hopkins Hospital dataset (18.9 [SE 6.9] vs 31.4 [12.0] years) and in the multicentre survey dataset (16.9 [7.4] vs 33.1 [11.9] years). The regression model confirmed the findings: the best-fitting model for the Johns Hopkins Hospital data showed an average 10.8 (SE 4.2) year difference in age at diagnosis between parent and child; that for the multicentre data showed an average difference of 15.1 (1.5) years. There was evidence of a further difference between the second and third generations. Disease was more extensive in the offspring than in the parent for 15 of the 27 pairs at Johns Hopkins Hospital; in 13 of these pairs the affected parent was the father.

INTERPRETATION

The evidence of a lower age at diagnosis and a greater extent of disease in the younger member of two-generation pairs affected by Crohn's disease, as well as the association with paternal transmission, suggest that genetic anticipation does occur in Crohn's disease. A search for triplet repeat regions is warranted.

A case-control study to examine the influence of maternal perinatal behaviors on the incidence of Crohn's disease

This case-control study, which examines maternal perinatal characteristics and behaviors during pregnancy, was an initial step to determine whether an association exists between breast feeding, oral contraceptive use, smoking habits during pregnancy, and the incidence of Crohn's disease. The population studied was mothers whose children were diagnosed with Crohn's disease before the age of 22. Population controls were selected by each case mother, who solicited two friends or neighbors with a child of similar age. Case mothers differed significantly on the variables of allergies (p = .05) and family history of inflammatory bowel disease (p = .001). No significant differences were found regarding feeding, oral contraceptives, or smoking. Using a forward step-wise logistic regression method, only family history remained in the equation.

Inflammatory bowel disease in children

IBD is one of the most significant chronic diseases afflicting children and adolescents. As in adults, UC and CD constitute the two major disease entities, with many of the characteristics of these two diseases being similar in adults and children. With technical advances, a complete endoscopic examination of the colon and terminal ileum can be performed in most children without difficulty. There are, however, a number of aspects of the presentation, course, and management of these diseases that are unique to the pediatric population. Because the impact of inadequate nutrition is much greater in the growing child than in adults, growth failure is a common, serious complication of malnutrition in this population. The psychological impact of a chronic illness on both the developing child and the family can also be significant. The management of this population is further complicated by the lack of adequate studies that assess not only the effect of a medical or surgical therapy on disease activity, but also address the issues of growth and pubertal development. It has been a challenge to extrapolate data from adult studies to the pediatric population. The management of children and adolescents requires a critical understanding of the differences between pediatric and adult patients to maximize growth potential and minimize longterm sequelae of treatment. After a long period of limited controlled studies, however, collaborative efforts are underway to investigate most aspects of pediatric IBD, and we look forward to exciting advances toward the optimal management of children and adolescents with IBD.

Investigation of inheritance of chronic inflammatory bowel diseases by complex segregation analysis

OBJECTIVE

To investigate the mode of inheritance of ulcerative colitis and Crohn's disease by complex segregation analysis.

DESIGN

Cross sectional population based survey of familial occurrence of chronic inflammatory bowel disease.

SETTING

Population of the Copenhagen county in 1987.

SUBJECTS

662 patients in whom inflammatory bowel disease had been diagnosed before 1979, of whom 637 (96%) provided adequate information. Of 504 patients with ulcerative colitis, 54 had 77 relatives with ulcerative colitis and of 133 patients with Crohn's disease, five had seven relatives with Crohn's disease.

MAIN OUTCOME MEASURES

Patterns of segregation of either disease as assessed by complex segregation analysis performed with the computer program POINTER.

RESULTS

The analysis suggested that a major dominant gene with a penetrance of 0.20-0.26 is present in 9-13% of adult patients with ulcerative colitis. The analysis did not allow for other components in the familial aggregation. For Crohn's disease the best fitting model included a major recessive gene with complete penetrance, for which 7% of the patients are homozygous. However, this model was not significantly different from a multifactorial model.

CONCLUSIONS

The segregation pattern indicates that a major dominant gene has a role in ulcerative colitis, and suggests that a major recessive gene has a role in Crohn's disease.

Familial inflammatory bowel disease in a paediatric population

Familial aspects of inflammatory bowel disease (IBD) were assessed as part of an age and sex matched case control study of 91 children with IBD and 131 controls. The prevalence of IBD in family members of the children was studied, the affected side (mother's side or father's side) of the family was documented and the type of inflammatory bowel disease was traced among relatives. Data were collected from children in out-patient clinics at a large urban tertiary-care facility. All family data were verified with the affected relatives and/or their physicians. The children with IBD (the cases) had significantly (P = 0.0000385) more IBD in their families than the controls. Among all children with IBD in their family, IBD was found significantly (P = 0.0073) more often on the mother's side of the family than on the father's side. Patterns of disease varied within families. A mixture of ulcerative colitis and Crohn's disease was found within families. The implications of the findings are discussed. Directions for prevention, screening, early intervention and further study are given.

Familial aggregation of inflammatory bowel disease in northern Italy: a multicenter study. The Gruppo di Studio per le Malattie Infiammatorie Intestinali (IBD Study Group)

To assess the familial aggregation of inflammatory bowel disease (IBD) in Italy, the family pedigrees of 411 patients with ulcerative colitis (UC) and 241 patients with Crohn's disease (CD) seen at 14 participating hospitals were studied. Sufficient information was obtained on 97% of 3752 first-degree relatives, 80% of 8869 second-degree relatives, and 74% of 5791 cousins. Thirty-six propositi (5.52%) had a total of 44 affected relatives (16 CD, 28 UC). The prevalence of IBD was higher in first- than in second-degree relatives and cousins (791, 112, and 163 in 100,000, respectively). A strong intrafamilial disease concordance was observed, with 26 cases of UC and 6 of CD among relatives of UC patients and 10 cases of CD and 2 of UC among relatives of CD patients. The prevalence of UC among first-degree relatives of UC patients and that of CD among first-degree relatives of CD patients was 680 and 531 in 100,000, respectively. In conclusion, there is a high degree of familial aggregation for IBD in Italy, with a strong intrafamilial disease concordance.

Incidence and prevalence of Crohn's disease in the county of Copenhagen, 1962-87: a sixfold increase in incidence

The incidence of Crohn's disease increased sixfold from 1962 to 1987 in the county of Copenhagen. The mean annual incidence for 1979-87 was 4.1 per 10(5) inhabitants. The increase was found equally in both sexes, with an approximately 40% higher incidence in women. The maximal incidence was found in the 15- to 24-year age group, being 12.8 per 10(5) per year for women and 6.0 per 10(5) per year for men, as mean of the period 1979-87. The prevalence at the end of the study was 54 per 10(5) inhabitants, 46 per 10(5) in men and 63 per 10(5) in women. The clinical appearance of the disease at the time of diagnosis was remarkably similar during the study period with regard to both the localization of disease and the clinical symptoms and signs. A slightly higher percentage of the patients, however, were in high disease activity at diagnosis in the later years of the study.

Crohn's disease among ethnic groups in a large health maintenance organization

The epidemiology of Crohn's disease (CD) was investigated among ethnic groups in a 2-million-member health maintenance organization. Between 1982 and 1988 there were 909 hospitalizations for CD. Annual hospitalizations per 100,000 were much lower for Hispanics (0.6) than those for whites (10.2) and blacks (10.2), and rates were higher among women (8.3) than men (6.0) (P less than 0.001). Bimodal age distributions were found for both sexes with peaks identified in the 20-29-year and greater than or equal to 60-year age groups. Annual age-adjusted hospitalizations per 100,000 decreased from 1982 (8.3) through 1988 (5.4) (P less than 0.05). A mail survey and medical records were used to collect data from the 169 CD patients who were identified at two sites within the organization. Prevalence rates per 100,000 for Hispanics (4.1) and Asians (5.6) were much lower than those for whites (43.6), blacks (29.8), and "others" (8.4). The distribution of age at diagnosis was bimodal, and the average age at diagnosis was 36 years. Patients reported an average of 3.7 outpatient visits and 13.3 days lost from work per year. Current cigarette smokers reported significantly more days troubled by symptoms during a one-month period (15.4 days) than nonsmokers (5.0 days) (P less than 0.001).

Concordance of familial characteristics in Crohn's disease and ulcerative colitis

The diagnosis of inflammatory bowel disease (IBD) in a proband increases the probability of a parallel IBD diagnosis in a family member. In this study, we were able to confirm the IBD diagnosis in 35 (9.9 percent) of the relatives of 352 registry probands. To confirm a proband's report of a positive family history of IBD, efforts were made to directly contact all first-degree relatives regardless of their IBD status (parents, siblings, and children). Consent to contact family members was obtained from the proband, who furnished the registry personnel with names, addresses, and phone numbers. We then attempted to contact each identified relative by phone. After verbal consent was obtained, family members were asked if they had been diagnosed with IBD. This diagnosis was confirmed by contacting the relative's physician. A McNemar (chi 2 Mc) matched-pair analysis was used to analyze concordance between the proband and the affected family member. Within the CD/CD (Crohn's disease) concordant pairs, sex was a significant risk factor. Sex was not a significant risk factor within the UC/UC (ulcerative colitis) concordant pairs. In the concordant surgery pairs, no surgical procedure was a significant risk factor for the prediction of a similar surgical procedure for the affected relative. In concordant extraintestinal complications, only the appearance of a skin rash was significantly related to the appearance of a skin rash in the affected relative.

Inflammatory bowel disease. Part I: Nature and pathogenesis

Once regarded as medical curiosities, ulcerative colitis and Crohn's disease have achieved a remarkable change in status recently and today are among the more compelling of all human illnesses. The cause(s) of inflammatory bowel disease (IBD) are not known. Genetic, environmental, microbial, and immunologic factors are involved, but the precise mechanisms are obscure. The incidence of ulcerative colitis is relatively stable, while Crohn's disease continues to increase in frequency. In 10% to 15% of patients, it is hard to differentiate between ulcerative colitis and Crohn's colitis; however, problems with diagnosis usually resolve with time and repeated examinations. In part I of his two-part monograph on IBD, Dr. Kirsner addresses the nature and pathogenesis of the disease. Increased study of ulcerative colitis and Crohn's disease in recent years has generated new knowledge regarding their etiology. Part I focuses on microbial, immunologic, and genetic mechanisms and the inflammatory processes involved in the disease. In part II, which will be presented in next month's issue of Disease-a-Month, Dr. Kirsner deals with the clinical features, course, and management of IBD, based on the author's 55 years of experience with these problems and supplemented by critical examination of the recent (1988-1990) literature. Particular attention is directed to the symptoms and physical findings of ulcerative colitis and Crohn's disease, the laboratory, radiologic, endoscopic, and pathologic features, and the many systemic complications. The IBDs are mimicked by several enterocolonic infections and other conditions, making differential diagnosis necessary. Inflammatory bowel disease in children and the elderly conforms to conventional clinical patterns modified by the health circumstances of the respective age groups. Because the cause of IBD has not been established, current medical therapy is facilitative and supportive rather than curative. The principles of medical treatment are approximately the same for ulcerative colitis and Crohn's disease. Treatment emphasizes a program rather than a drug and also considers the individuality of the therapeutic response. A clearer understanding of dietary and nutritional needs, including hyperalimentation and electrolyte and fluid balance, aids treatment. Antidiarrheal and antispasmodic preparations and sedatives are prescribed for symptom relief. The bowel inflammation is controlled with sulfasalazine or the newer 5-amino salicylic acid (5-ASA) compounds, antibacterial drugs for complications of Crohn's disease and IBD, adrenocortical steroids, and the immunosuppressive compounds 6-mercaptopurine (6-MP), azathioprine, and cyclosporine, as determined in each patient. The surgical procedures available for treatment of ulcerative colitis include total proctocolectomy and ileostomy or ileoanal anastomosis.(ABSTRACT TRUNCATED AT 400 WORDS)

The epidemiology of inflammatory bowel disease in children: a pilot project

A major study about the epidemiology of inflammatory bowel disease in children was planned. A pilot study of pre-morbid variables among 42 children with the disease was undertaken. Conducting a pilot study was an essential component of the research process, both in refining the data collection instrument and in maximizing the use of technology. Results of the pilot study are described and the way in which they were used to prepare a better major study are discussed.

Frequency of inflammatory bowel disease in offspring of couples both presenting with inflammatory bowel disease

A private practice was surveyed for prevalence of inflammatory bowel disease (IBD) in husband-wife partners and in their children. Among approximately 2500 patients with IBD in our files, 19 couples were identified. They were subdivided into group A (n = 5) in which both partners had symptoms of IBD before marriage; group B (n = 7) in which only one spouse had IBD before marriage and the other partner experienced symptoms afterwards; and group C (n = 7) in which neither spouse had symptoms before marriage but IBD subsequently developed in both. In group B, the disease developed in the second spouse 2-16 years after marriage (mean, 6.4 years). In group C, IBD developed in the first spouse 0.3-41 years after marriage and in the second spouse 1-14 years after the first spouse (mean, 6.8 years). Thirty-five children have been born to 16 of the couples. Two children died before age 20. Of the surviving 33 children, IBD has already developed in 12 (36%). Among the other 21 unaffected children, 1 had uveitis at age 9 and 10 are still under the age of 21, perhaps too young to have yet developed IBD. The frequency of IBD in children was slightly higher if both parents had already developed IBD at the time of conception (67%) compared with when only 1 parent (50%) or neither parent (50%) had developed IBD when conception occurred. Although these data do not distinguish genetic from environmental factors, they show a higher risk of IBD in children when both parents have this illness.

Prevalence of inflammatory bowel disease in family members of Jewish Crohn's disease patients in Israel

A familial study of 189 Jewish Crohn's disease patients was conducted in order to evaluate the risk for inflammatory bowel disease (IBD) in relatives of the patients and to try to understand better the genetic component in the etiology of the disease among Jews. One hundred fifty-seven patients filled out questionnaires that were verified by personal interviews. In 10 families (6.6%), a first-degree relative of the propositus was found to have IBD, seven Crohn's disease and three ulcerative colitis. Among first-degree relatives, siblings were more frequently affected: of 400, five had Crohn's disease and one ulcerative colitis. Among 304 parents, two had Crohn's disease and two ulcerative colitis, while none of the propositi's children had IBD. The prevalence of first-degree relatives with Crohn's disease was similar in the 98 and 45 families of Ashkenazi and non-Ashkenazi origin: 5.1% and 4.4%, respectively. The risk for siblings of the probands to be affected were also similar in the two groups: 1.5% and 1.8%; while parents of the probands were affected only in the group of Ashkenazi Jews.

Prevalence of inflammatory bowel disease among relatives of patients with Crohn's disease

The prevalence of familial inflammatory bowel disease was 13.4% in a population-based study of 1048 patients with Crohn's disease (CD). Seventy-two of the index cases had 82 first-degree relatives. Forty-nine were more distantly related (19 first cousins from the same generation as the index patient). The prevalence of CD among first-degree relatives was 21 times higher than among non-relatives. Four of six monozygotic twins were concordant. The age at onset was 25 years in the patients with familial CD, compared with 33 years in the entire group. An additional 53 relatives were found to have ulcerative colitis (UC). The prevalence of UC among first-degree relatives of patients with CD was six times higher than among non-relatives.

Familial occurrence of inflammatory bowel disease

BACKGROUND AND METHODS

We assessed the familial occurrence of inflammatory bowel disease in Copenhagen County, where there has been a long-term interest in the epidemiology of such disorders. In 1987 we interviewed 662 patients in whom inflammatory bowel disease had been diagnosed before 1979, asking whether their first- and second-degree relatives had this disorder. Ninety-six percent of the patients (504 with ulcerative colitis and 133 with Crohn's disease) provided adequate information.

RESULTS

As compared with the general population, the first-degree relatives of the 637 patients with ulcerative colitis or Crohn's disease had a 10-fold increase in the risk of having the same disease as the patients, after standardization for age and sex. The risk of having the other of the two diseases was also increased, but less so, and the increase in the risk of having Crohn's disease was not significant in the relatives of patients with ulcerative colitis. The risk of ulcerative colitis in first-degree relatives of patients with ulcerative colitis appeared to be virtually independent of the generation to which the first-degree relative belonged and of the sex of the patient and the relative. The risk of ulcerative colitis in first-degree relatives tended to be higher if the disease had been diagnosed in the patient before the age of 50, but the risk seemed to be independent of the current age of the relatives. The prevalence of the same disease as that of the patient (either ulcerative colitis or Crohn's disease) among second-degree relatives was increased; the prevalence of the other disease was not increased.

CONCLUSIONS

The 10-fold increase in the familial risk of ulcerative colitis and Crohn's disease strongly suggests that these disorders have a genetic cause.

Genetic aspects of inflammatory bowel disease

There is ample evidence in the literature that both Crohn's disease and ulcerative colitis are at least partly caused by genetic factors. For the future, it is important to locate markers that can separate patients from healthy individuals. The relative importance of these markers in the etiology can then be investigated by using statistical methods such as segregation analysis.