Epidemiological aspects of Crohn's disease: a review of the literature

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.

Hispanics and inflammatory bowel disease

BACKGROUND

Historically, inflammatory bowel disease (IBD) was considered a disease, which predominately affects whites. As such, the majority of research in IBD has been conducted in this population. However, more research on this suggests that IBD affects other ethnic groups. Rapidly shifting demographics in the United States necessitates a better understanding of how IBD may affect Hispanics. We reviewed the current literature on IBD in Hispanics.

METHODS

A PubMed search was conducted using keywords inflammatory bowel disease, Ulcerative Colitis, Crohn's disease, Hispanics, Latinos, ethnicity, to identify existing literature with a focus on adult populations. Non-English language articles were excluded.

RESULTS

The existing data and literature on Hispanic patients with IBD remains sparse. Limited studies on prevalence suggest IBD may be more common in Hispanics in the United States compared with those in Latin America. Conflicting data exist as to whether Hispanics patients with IBD are more likely to have ulcerative colitis compared with Crohn's disease. One study explored difference in IBD between foreign-born and U.S.-born Hispanics and found that ulcerative colitis was more common only in foreign-born Hispanics, whereas within 1 generation, U.S.-born Hispanics resemble their non-Hispanic white counterparts about development of Crohn's disease. Such a rapid change in the proportion of ulcerative colitis and Crohn's disease points strongly to environmental factors driving the change in proportion of disease subtypes. Additionally, a trend towards less use of biologic and immunomodulators in Hispanics was noted in several studies.

CONCLUSIONS

Additional research is needed to better understand how diversity within the Hispanic population (U.S.-born and foreign-born) may be driving difference in disease manifestations. More investigations should focus on determining the cause of a potential disparity in the use of biologic and immunomodulators in Hispanics.

INFLAMMATORY BOWEL DISEASE IN HISPANIC COMMUNITIES: a concerted South American approach could identify the aetiology of Crohn’s disease and ulcerative colitis

Despite intensive research we remain ignorant of the cause of both Crohn’s disease and ulcerative colitis. The dramatic rise in incidence, particularly of Crohn’s disease, points towards environmental factors as playing a significant role. A major purpose of this review is to stimulate a co-ordinated international effort to establish an on-going data base in Central and South America in which new cases are registered and through which investigations into aetiology can be conducted. In both Brazil and Mexico there is evidence that the incidence of ulcerative colitis is increasing, as also is the case for Crohn’s disease in Brazil. The pattern of disease is, therefore, directly comparable to that reported from Europe and the USA during the 1970s and 1980s, but much lower than contemporary data from Spain. Although the incidence is similar to that reported from Portugal, the studies from Almada and Braga were conducted a decade before that from Sao Paulo. The situation in Brazil compares dramatically with Uruguay and Argentina where the reported incidence of inflammatory bowel disease is significantly less. However, with growing industrialisation it is likely that there will be an explosion of inflammatory bowel disease in some areas of Central and South America over the next 20 years. The creation of a network of researchers across South and Central America is a real possibility and through a Concerted Action there is the possibility that major strides could be made towards understanding the cause of inflammatory bowel disease and so develop preventive strategies.

Incidence and paris classification of pediatric inflammatory bowel disease

New epidemiological data suggest that the incidence of inflammatory bowel disease (IBD) is increasing. As a result the burden of disease accounts for more strains to the health care system. The clinical variability queries whether disease characteristics are related to clinical outcome. Our aim was to delineate the latest results of incidence trends in pediatric IBD and to compare the first experiences with Paris Classification. Incidence of pediatric IBD has been increasing in Western Europe and in Eastern Europe. To better characterize IBD, Paris Classification was introduced and validated recently. Ileocolonic involvement is the most characteristic disease location in Crohn's disease (CD) based on applying Paris Classification. The rate of perianal disease and complicated behaviour in CD was similar. It is of interest that CD patients with colonic involvement were less likely to have stricturing disease compared with patients with ileal involvement. In addition, pancolitis dominated in ulcerative colitis (UC). However, most countries lack prospective, nationwide epidemiological studies to estimate incidence trends. This review emphasizes the importance of nationwide registries that enroll all pediatric IBD cases serving reliable data for "everyday practice." These first reports have shown that Paris Classification is a useful tool to determine the pediatric IBD phenotype.

Does evidence exist to include dietary therapy in the treatment of Crohn's disease?

Prescription drugs and surgery are two common medical therapies for Crohn's disease (CD), an inflammatory bowel disease that affects the GI tract. Unfortunately, certain drugs can cause serious side effects, and surgeries must often be repeated. No diet has been established to alleviate the pain and suffering of CD patients. This is curious given the fact that a higher prevalence of food sensitivities exist in this population of patients, and enteral nutrition is not only the first-line of therapy in Japan, but a known research method used to place the majority of CD patients into remission. Although not all patients respond equally to diet, many simply remove symptom-provoking foods, such as dairy, wheat, corn and certain fruits and vegetables. We suggest assisting these patients in their self-assessment of irritating and symptom-provoking foods by educating them in the use of a food-symptom diary followed by a customized elimination diet trialed for 2-4 weeks to determine if there is any benefit to the individual patient.

Role of Klebsiella and collagens in Crohn's disease: a new prospect in the use of low-starch diet

Crohn's disease is suggested to result from a microbially triggered immune-mediated autoimmune process, involving mainly the terminal ileum and ileo-caecal junction. Klebsiella pneumoniae shares certain molecular structures present in pullulanase pulA and pulD secretion enzymes with various self-antigens present in collagens and HLA-B27 molecules, respectively. A link exists between high dietary starch intake and the growth of intestinal microflora, involving especially Klebsiella microbes. Increased exposure to Klebsiella in the gut as the result of high starch intake would lead to high production of antiKlebsiella antibodies as well as autoantibodies to the cross-reactive self-antigens with the resultant inflammation at the pathological sites. Eradication of these microbes from the gut in patients with Crohn's disease with the use of low-starch diet and antibacterial agents as well as immunomodulatory measures could be beneficial in the management of this disease.

Expression profiles of human 11beta-hydroxysteroid dehydrogenases type 1 and type 2 in inflammatory bowel diseases

Inflammatory bowel diseases such as Crohn's disease (CD) and ulcerative colitis (UC) are characterized by an increase in pro-inflammatory cytokines. On the other hand, endogenous cortisol is regarded as physiological compound to combat inflammation. The local activation of glucocorticoids is mediated by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) which increases cortisol, and 11beta-HSD2 which decreases cortisol concentrations. We hypothesized that in inflamed tissues of patients suffering from inflammatory bowel diseases 11beta-HSD1 is upregulated whereas 11beta-HSD2 is downregulated. By using quantitative real-time PCR, we investigated the transcription levels of 11beta-HSD1 and 11beta-HSD2 in patients diagnosed with CD or UC. Expression of 11beta-HSD1 was significantly elevated in inflamed tissue compared to non-inflamed colonic tissue in both, CD (2.7-fold) and UC (3.8-fold), whereas 11beta-HSD2 expression was decreased in the same samples. In both diseases, male patients showed a more pronounced upregulation of 11beta-HSD1 (CD: 4.8-fold, UC: 6.5-fold) compared to females (CD: 1.8-fold, UC: 1.8-fold), a fact which might be due to the higher levels of circulating anti-inflammatory estrogens in women. Our data support the hypothesis that both enzymes play a crucial role in inflammation by affecting local tissue ratios between active and inactive glucocorticoids.

Crohn's disease and early exposure to domestic refrigeration

Background

Environmental risk factors playing a causative role in Crohn's Disease (CD) remain largely unknown. Recently, it has been suggested that refrigerated food could be involved in disease development. We thus conducted a pilot case control study to explore the association of CD with the exposure to domestic refrigeration in childhood.

Methodology/Principal Findings

Using a standard questionnaire we interviewed 199 CD cases and 207 age-matched patients with irritable bowel syndrome (IBS) as controls. Cases and controls were followed by the same gastroenterologists of tertiary referral clinics in Tehran, Iran. The questionnaire focused on the date of the first acquisition of home refrigerator and freezer. Data were analysed by a multivariate logistic model. The current age was in average 34 years in CD cases and the percentage of females in the case and control groups were respectively 48.3% and 63.7%. Patients were exposed earlier than controls to the refrigerator (X2 = 9.9, df = 3, P = 0.04) and refrigerator exposure at birth was found to be a risk factor for CD (OR = 2.08 (95% CI: 1.01–4.29), P = 0.05). Comparable results were obtained looking for the exposure to freezer at home. Finally, among the other recorded items reflecting the hygiene and comfort at home, we also found personal television, car and washing machine associated with CD.

Conclusion

This study supports the opinion that CD is associated with exposure to domestic refrigeration, among other household factors, during childhood.

[Socioeconomic and nutritional profile of patients with inflammatory bowel disease at a university hospital]

BACKGROUND

Inflammatory bowel diseases include chronic and relapsing inflammatory disorders, represented by ulcerative proctocolitis and Crohns disease, commonly associated with malnutrition.

AIM

Characterize the nutritional and socioeconomic profile of patients hospitalized at the Pernambuco "Hospital das Clínicas", Recife, PE, Brazil.

METHODS

Cross-sectional study carried out at the gastroenterology clinic, which was previously approved by the Ethics Commission for studies involving human beings. The methods included clinical history data, socioeconomic conditions and nutritional assessment. Data were subject to statistical analysis (Students t test for equal and unequal variables).

RESULTS

The sample consisted of 24 male and female patients, with a mean age of 43.83 +/- 16.13 years, mostly married, coming from Recife, with low income, who lived in their own house with relatives. We found a higher prevalence of ulcerative proctocolitis (62.5%), with diagnosis time of more than 5 years, symptoms of abdominal pain, bloody-mucous diarrhea with 6-9 evacuations/day, with the distal colon being the most affected part. Osteoporosis was present in 26.7% of cases. Nutritional status was assessed through the body mass index. The weight loss percentage corresponded to 41.7% and 70.8%, respectively, classified as malnourished, associated or not with high prevalence levels of anemia, hypoalbuminemia and hypocalcemia. Gender correlation evidenced higher triceps fold and arm circumference values in men.

CONCLUSIONS

Despite the study limitations, data suggest relevant information about the occurrence of these diseases in the northeast of Brazil, as well as about its frequent association with important nutritional deficiencies.

Differences in yeast intolerance between patients with Crohn's disease and ulcerative colitis

PURPOSE

Alimentary factors, especially those modifying the intestinal flora, may influence the course of inflammatory bowel disease. It is known that T and B cells of patients with Crohn's disease can be stimulated with the yeast antigen, mannan. We evaluated the impact of eating habits with special respect to food containing yeast on the course of inflammatory bowel disease.

METHODS

Questionnaires were sent to 180 German-speaking patients of the Inflammatory Bowel Disease Outpatient Clinic at the University Hospital Bern, Switzerland. The following information was obtained by the questionnaires: (1) course of disease, (2) eating habits, (3) environmental data, and (4) inflammatory bowel disease questionnaire. The survey was anonymous.

RESULTS

A total of 145 patients (80.5 percent 95 with Crohn's disease, and 50 with ulcerative colitis) responded. Food items containing yeast were better tolerated by patients with ulcerative colitis than by patients with Crohn's disease. A significant difference between the two groups was observed concerning food containing raw yeast (dough, P = 0.04; and pastry, P = 0.001).

CONCLUSIONS

Food items containing raw yeast led to more frequent problems for patients with Crohn's disease than for patients with ulcerative colitis. This observation supports our previous data, which showed the stimulatory effect of the yeast antigen, mannan, on B and T cells of patients with Crohn's disease but not of controls.

Effect of race and ethnicity on perceptions of inflammatory bowel disease

BACKGROUND AND AIMS

Historically, inflammatory bowel disease (IBD) was thought to predominantly affect whites. However, IBD is now increasingly recognized in diverse ethnic populations. There is a paucity of studies of IBD in nonwhite populations, especially in Mexican Americans. The aims of this study were to compare the impact of IBD on the quality of life of whites, African Americans, and Mexican Americans and to evaluate differing patient understanding and beliefs regarding IBD.

MATERIALS AND METHODS

A questionnaire was administered to 148 patients between June 1999 and November 2003 at a university gastroenterology practice in Houston, Tex.

RESULTS

Caucasians (W) comprised 40%, African Americans (AA) 37%, and Mexican Americans (MA) 20% of the respondents. AA and W had predominantly Crohn's disease (CD), whereas MA had predominantly ulcerative colitis (UC; P<0.05). We therefore compared W and AA with CD and W and MA with UC. W were more likely to tell their employers (57% vs 27.5%, P=0.02), fellow employees (68% vs 43.8%, P=0.02) and friends (100% vs 79%, P=0.034) that they had CD. W and AA were equally as likely to have regular checkups by a physician, and there was no difference in the access to gastroenterologists or surveillance colonoscopy. There were fewer differences between MA and W with UC. MA were more likely to believe that UC was caused by stress (70% vs 37%, p=0.044) and cigarette smoking.

CONCLUSIONS

Significant differences appear among racial and ethnic groups with IBD regarding attitudes toward disease and impact on daily life. Appreciation of varying ethnic and racial perceptions, attitudes, and beliefs among patients with IBD may be critical to more effective management.

Current concept on the pathogenesis of inflammatory bowel disease-crosstalk between genetic and microbial factors: Pathogenic bacteria and altered bacterial sensing or changes in mucosal integrity take “toll”

The pathogenesis of inflammatory bowel disease (IBD) is only partially understood. Various environmental and host (e.g. genetic-, epithelial-, immune and non-immune) factors are involved. It is a multifactorial polygenic disease with probable genetic heterogeneity. Some genes are associated with IBD itself, while others increase the risk of ulcerative colitis (UC) or Crohn’s disease (CD) or are associated with disease location and/or behaviour. This review addresses recent advances in the genetics of IBD. The article discusses the current information on the crosstalk between microbial and genetic factors (e.g. NOD2/CARD15, SLC22A46A5 and DLG5). The genetic data acquired in recent years help in understanding the pathogenesis of IBD and can identify a number of potential targets for therapeutic intervention. In the future, genetics may help more accurately diagnose and predict disease course in IBD.

Crohn's disease: presentation and severity compared between black patients and white patients

PURPOSE

Common belief based on clinical experience suggests that Crohn's disease is more severe among black patients, although little data exists on the effect of race on Crohn's disease. We compared multiple variables among black patients with Crohn's disease requiring surgery to those of white patients presenting to a university colorectal surgery unit during a five-year period.

METHODS

A total of 345 patients required surgery for Crohn's disease between June 1998 and September 2003. The following data were abstracted from patient charts and a prospectively maintained database: age at diagnosis; age at first Crohn's disease surgery; presenting symptoms; incidence, number and location of fistulas at presentation; number of Crohn's disease operations; and family history of inflammatory bowel disease. Data regarding medical insurance coverage also were obtained. Complete data were evaluable on 178 patients. Patient variables were analyzed using the chi-squared, Fisher exact, and Student t-tests.

RESULTS

Mean age at diagnosis was 28 years for white males, 20 years for black males, 30 years for white females, and 28 years for black females (all p > 0.05). Thirty-seven percent of white females presented with obstructive symptoms vs. 12 percent of black females. (P = 0.011). Sixty-five percent of black females presented with inflammatory symptoms compared with 28 percent of white females (P = 0.001). Of females presenting with fistulas, 15 percent of black patients had a rectovaginal fistula compared with 5 percent of white patients. Seventeen percent of black males and 21 percent of white males had intra-abdominal fistulas. None of these differences were statistically significant. The incidence of fistulas at presentation, mean number of fistulas, total number of operations, and family history of inflammatory bowel disease did not differ.

CONCLUSIONS

Contrary to expectations, Crohn's disease does not seem to be more severe among black patients, who had an earlier age of diagnosis, although this was not statistically significant. Overall, there was no difference in disease presentation. White females were more likely to present with obstructive symptoms compared with black females, who more often presented with inflammatory symptoms. Among patients with fistulas, the incidence of rectovaginal fistulas was higher in black females compared with white females, and white males were somewhat more likely to have intra-abdominal fistulas than black males. Although there was no demonstrated difference in incidence and mean number of fistulas at presentation, the number of operations for Crohn's disease, or family history of inflammatory bowel disease among blacks and whites, there are differences in presenting symptoms among these populations.

Etiology of Crohn’s disease: Do certain food additives cause intestinal inflammation by molecular mimicry of mycobacterial lipids?

Crohn's disease is a chronic granulomatous inflammation of the gastrointestinal tract which was first described in the beginning of the 20th century. The histological similarity with intestinal tuberculosis has led to the assumption of an involvement of mycobacteria and mycobacterial antigens, respectively, in the etiology. A major defense mechanism against mycobacterial lipid antigens is the CD1 system which includes CD1 molecules for antigen presentation and natural killer T cells for recognition and subsequent production of cytokines like interferon-gamma and tumour necrosis factor-alpha. These cytokines promote granulomatous transformation. Various food additives, especially emulsifiants, thickeners, surface-finishing agents and contaminants like plasticizers share structural domains with mycobacterial lipids. It is therefore hypothesized, that these compounds are able to stimulate by molecular mimicry the CD1 system in the gastrointestinal mucosa and to trigger the pro-inflammatory cytokine cascade. The understanding of Crohn's disease as a CD1-mediated delayed-type hypersensitivity to certain food additives would lead to strong emphasis on a dietary treatment. Related aspects of pathology, physiology and epidemiology of Crohn's disease are presented.

Enhanced glucose-dependent glucagon-like peptide-1 and insulin secretion in Crohn patients with terminal ileum disease is unrelated to disease activity or ileal resection

BACKGROUND

Enhanced secretion of glucagon-like peptide-1 (GLP-1) has been reported in patients with Crohn disease (CD). However, the correlation between the enteropancreatic axis and the activity of CD remains unclear.

METHODS

Plasma glucose, insulin, GLP-1 levels and insulin sensitivity were determined before and after oral glucose tolerance tests in 13 patients with CD of the terminal ileum, in 13 patients after resection of the terminal ileum and in 7 healthy controls. Basal and stimulated insulin sensitivities were determined using the homeostasis model assessment (HOMA) and the insulin sensitivity index (ISI) methods, respectively.

RESULTS

Basal and stimulated glucose levels were comparable in patients and controls. The peak stimulated GLP-1 secretion was significantly higher in the patient group compared to controls: 12.2 +/- 1.24 pM/L and 8.1 +/- 1.72 pM/L, respectively, P=0.03. This was associated with 52% increased overall insulin secretion in the patients' group as compared to controls (P=0.007) and a higher peak insulin response: 63.5 +/- 9.69 mU/L and 41.5 +/- 6.85 mU/L for patients and controls, respectively, P=0.04. Operated patients had similar GLP-1 levels but higher peak and overall insulin secretions compared with those in non-operated patients (P=0.01). Fasting and stimulated insulin sensitivities were reduced only in patients with ileal resection as compared to controls: P=0.01 and P=0.05, respectively. No correlation was found between the CD activity index and GLP-1 or insulin secretion.

CONCLUSIONS

CD of the terminal ileum is associated with enhanced glucose-dependent GLP-1 secretion, which is unrelated to disease activity or ileal resection.

Crohn's disease: the cold chain hypothesis

Crohn's disease is the result of an abnormal immune response of the gut mucosa triggered by one or more environmental risk factors in people with predisposing gene variations, including CARD15 mutations. Epidemiological data allow assessment of familial environmental risk factors related to western lifestyle, diet, bacteria, and domestic hygiene. All findings point to refrigeration as a potential risk factor for Crohn's disease. Furthermore, cold-chain development paralleled the outbreak of Crohn's disease during the 20th century. The cold chain hypothesis suggests that psychrotrophic bacteria such as Yersinia spp and Listeria spp contribute to the disease. These bacteria have been identified in Crohn's disease lesions and we discuss their pathogenic properties with respect to our knowledge of the disease. From a molecular perspective, we postulate that the disease is a result of a defect in host recognition by pathogenic bacterial components that usually escape the immune response (eg, Yop molecules), which results in an excessive host response to these bacteria.

Epidemiology of inflammatory bowel disease--methodological considerations

The causes and mechanisms of action of inflammatory bowel disease have, so far, eluded discovery. Epidemiological studies have shown that ulcerative colitis tends to level off, whereas Crohn's disease tends to increase. Some of these changes may be due to diagnostic practices and increasing awareness of the disease and Crohn's colitis. The disease varies according to geographical location and a distribution along a north-south axis has been suggested. The differences may be due to study design, or may reflect differences in lifestyle, diet or be due to genetic predisposition triggered by environmental factors. Epidemiological studies designed to investigate such interactions may provide clues to its aetiology. Inflammatory bowel disease could, therefore, serve as a model for the importance of epidemiology when to test or reject the hypothesis of aetiology.

Crohn's disease: does race matter? The Mid-Atlantic Crohn's Disease Study Group

OBJECTIVE

The severity of Crohn's disease (CD) has been reported to be greater in blacks than in whites. This possible disparity may be due, in part, to differences between these groups in health care utilization and accessibility. To explore these issues, we conducted a multicenter survey of patients with CD.

METHODS

One-hundred and forty-five blacks with CD, recruited from four teaching hospitals and five private practices, and identified by medical record review or ICD-9 code, were enrolled and matched to 407 whites with CD (by age, gender, and practice type [teaching vs. private practice setting]). Participants were interviewed regarding medical history, health status, personal health care practices during the preceding 5 yr, and beliefs regarding health care in the general population.

RESULTS

Blacks and whites were similar with respect to age of CD onset, lag in time to diagnosis, and number of gastrointestinal (GI)-related hospitalizations and surgeries. Medication usage patterns were also similar in the two groups. Quality of life, measured by SF-36, was lower in all categories for blacks, compared with whites. Blacks were more likely to have had to stop work (p<0.01) and have lost more work days (p<0.01) than were whites. Whites were more likely to have health insurance and be able to identify a regular provider than were blacks. Blacks were more likely to report the following: receiving Medicaid; difficulty affording health care; delaying appointments due to financial concerns; difficulty traveling to their provider's office; and experiencing unreasonable delays at their provider's office. After adjusting for potential confounding variables, we found no differences between the groups, except for the number of days of work lost because of CD.

CONCLUSIONS

These data suggest that black and white patients have similar reported disease presentations and course, and contrast with prior reports suggesting a more severe disease course among black patients. Although the disease itself appears similar, there were numerous reported differences between the races in health care utilization practices and in disease impact upon daily activities. We suggest that apparent disparities in CD according to race are actually due to social and economic factors, and not to the disease itself.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The relationship between habits of food consumption and reported reactions to food in people with inflammatory bowel disease--testing the limits

Anecdotally, people with inflammatory bowel disease (IBD) report that some foods make them feel better and some foods make them feel worse. This paper reports about the relationship between food habits and reactions to foods in people with IBD. A database was designed to incorporate the date of data collection, the IBD disease, food habits, the quantity consumed and a response rating of the subjects' reactions to each food. For each of 122 foods, subjects were asked simultaneously about these five categories. Thirty three subjects with Crohn's disease and 27 with ulcerative colitis completed the questionnaire in two seasons. The focus of the examination was directed to the upper and lower limit of reactions to foods. Foods that affect people negatively and foods that affect people positively were identified in relation to habits of consumption. Foods that affect people negatively were among those never consumed while foods that affect people positively were among the regularly consumed foods. Findings included an increased number of foods that caused problems for people with Crohn's disease when compared with people with ulcerative colitis. Problems with chocolate, dairy products, fats and artificial sweeteners were documented in both groups of IBD. A standard food list generated without the input of individuals with a chronic illness may be inadequate to collect data about their consumption since many of the foods on the list were reportedly never consumed and there may be other foods not on the list that are consumed by this chronically ill population.

Pre-illness dietary factors in inflammatory bowel disease

BACKGROUND

The effect of environmental factors has been demonstrated in the pathogenesis of inflammatory bowel disease (IBD). Nutrition may be one of them.

AIM

To investigate the pre-illness diet in patients with recent IBD in comparison with matched population and clinic controls.

METHODS

Quantified dietary histories were obtained from 87 patients with recent IBD (54 ulcerative colitis (UC) and 33 Crohn's disease (CD)) and 144 controls. Odds ratios (OR) for IBD were derived for intake levels of various foods.

RESULTS

A high sucrose consumption was associated with an increased risk for IBD (OR 2.85 (p = 0.03) against population controls and 5.3 (p = 0.00) against clinic controls). Lactose consumption showed no effect while fructose intake was negatively associated with risk for IBD (NS). Similar trends were noted in UC and CD. A high fat intake was associated with an increased risk for UC; this was particularly marked for animal fat (OR 4.09, p = 0.02) and cholesterol (OR 4.57, p = 0.02). A high intake of fluids (p = 0.04), magnesium (p = 0.04), vitamin C, and fruits (NS) was negatively associated with the risk for IBD, while a positive association was found for retinol (p = 0.01). Most of the findings were similar in UC and CD except for potassium and vegetable consumption which showed a negative association only with risk for CD.

CONCLUSIONS

An association was found between pre-illness diet and subsequent development of UC and CD. The effect of dietary components may be primary or modulatory.

Inflammatory bowel disease: re-evaluation of the diagnosis in a prospective population based study in south eastern Norway

BACKGROUND

The incidence figures for ulcerative colitis (UC) and Crohn's disease (CD) have been difficult to interpret, and geographical variations may be due to differences in classification criteria and study design. Few studies have based the incidence on prospective systematic follow up to confirm the initial diagnosis.

METHODS

Between 1990 and 1993, in a prospective incidence study of inflammatory bowel disease (IBD) in south eastern Norway, 527 cases of UC, 228 cases of CD, 36 cases of indeterminate colitis (IND), and 55 cases of possible IBD were identified, yielding an annual incidence of 13.6, 5.9, 0.9, and 1.4 per 10(5) respectively. The diagnosis and all clinical data were reviewed by two gastroenterologists independently of each other. One to two years after diagnosis, all patients were offered a clinical follow up in which the initial diagnosis was assessed.

RESULTS

Between the time of diagnosis and the follow up, 16 patients had died, four of complications related to IBD. Of the remaining 830 patients, 98% (814/830) were available for follow up, 93% (772/830) attended a clinical examination which included a colonoscopy in 77% (637/830), and the remainder had had a telephone interview, or reassessment based on hospital records, or both. Twenty seven patients were reclassified as not having IBD (3%), and 65 patients were characterised as possible IBD (8%). Of the patients initially classified as UC, 88% had their diagnosis confirmed, compared with 91% with an initial diagnosis of CD. In patients with indeterminate colitis, 33% were classified as definite UC and 17% as CD. This reclassification of patients yielded a corrected annual incidence of 12.8 for UC and 6.0 for CD.

CONCLUSION

At follow up one to two years after the diagnosis of IBD, the initial incidence was only marginally altered. This is probably due to uniform inclusion criteria and careful diagnostic methods. The study also illustrates the importance of the re-evaluation of the initial diagnosis as close to 10%, both among patients with UC and CD, were reclassified at follow up.

Incidence of Crohn's disease in four counties in southeastern Norway, 1990-93. A prospective population-based study. The Inflammatory Bowel South-Eastern Norway (IBSEN) Study Group of Gastroenterologists

BACKGROUND

Standardized criteria for Crohn's disease (CD) have only recently been developed, and prospective community-based incidence studies have been performed only during the past 3 decades. Geographic variations in incidence may therefore be due to differences in study design.

METHODS

From 1 January 1990 to 31 December 1993 all new cases of CD in four counties in southeastern Norway were prospectively registered.

RESULTS

A total of 225 new cases yielded an annual incidence of 5.8/10(5), with the highest incidence in mixed rural-urban areas. A peak of 11.2/10(5) in the annual incidence was found for the age group 15 to 24 years, with no significant differences in the overall annual incidence by gender. An average duration of 6 months of disease before diagnosis was unchanged during the 4 years. About half of the patients had isolated colonic disease, and one-quarter had isolated small-bowel disease.

CONCLUSIONS

This study confirms the high incidence figures for Scandinavia, with a particularly high incidence in mixed rural-urban areas. Ileocolonoscopy improves the accuracy of the diagnosis and of the determination of disease extent, which may have therapeutic implications for the treatment and follow-up of patients.

Lack of association between smoking and inflammatory bowel disease in Jewish patients in Israel

BACKGROUND/AIMS

An excess of smokers in patients with Crohn's disease (CD) and a paucity of smokers in patients with ulcerative colitis (UC) were reported in many studies. The aim of this study was to examine the association between smoking and inflammatory bowel disease (IBD) in Israel.

METHODS

Two independent studies were performed. Patients with recent IBD in comparison with matched population and outpatient controls and patients with chronic UC and CD were studied. Altogether, 475 subjects were investigated.

RESULTS

In both studies, the presence of current smokers was lower in CD (9% and 18%) than in UC (24% and 26%). The proportions of nonsmokers in both studies were similar (UC, 61% and 65%; CD, 67% and 70%) and comparable to those found in their two control groups (57% and 61%; 63% and 68%, respectively) and to the general population of Israel. All differences in smoking habits between patient groups and their controls were not statistically significant, except for the paucity of current smokers in the small group of patients with newly diagnosed CD (P < 0.05). A matched analysis produced similar results.

CONCLUSIONS

The expected associations between smoking and IBD could not be confirmed. Two hypotheses are considered: (1) the association between smoking and IBD may not be universal, and (2) our findings may be related to the higher genetic predisposition to IBD in Jewish people.

The course of inflammatory bowel disease

Ulcerative colitis (UC) and Crohn's disease (CD) are chronic disorders affecting mostly young people, punctuated by relapses and remissions. There is a pattern for UC based on the original extent of colon involved. Ulcerative proctosigmoiditis is a limited form of the disease with a generally benign course. Although UC tends to relapse, treatment reduces the relapse rate. CD has protean manifestations. The anatomic location and extent of disease tends to determine the clinical course. Most patients require surgery, and recurrences are common.

Inflammatory bowel disease and refractory anaemia (myelodysplasia)

Two patients with colitis and refractory anaemia requiring multiple transfusions are described. In one the anaemia was detected at the onset of colitis before drug treatment; in the other it started after 21 years of treatment with sulphasalazine and during an exacerbation of colitis with perianal abscess for which he had just been started receiving prednisolone, cofluampicil and metronidazole. Glomerulonephritis developed two weeks after the onset of anaemia. These findings together with a recent report of four patients with Crohn's disease and refractory anaemia suggests that the association may be more than coincidental and may be immune mediated.

Behçet's syndrome in Scotland

We present the clinical details and HLA typing of 15 Celtic Caucasian patients (four male, 11 female) with Behçet's syndrome (International Study Group criteria). The males affected were younger than the affected females, and three of these males had severe uveal involvement. Two of the 15 patients had the A2 Bw6 Dr4 haplotype but this did not confer family penetrance. Eight had gastrointestinal involvement: two females required ileostomy, two females had chronic diarrhoea, one female had severe ileitis and oesophageal lesions, two males had peptic ulcers, and one female had a peptic ulcer and primary biliary cirrhosis. All of those who developed gastrointestinal symptoms had either the Dr4 or the Dr7 antigens. This study is the largest HLA survey of Celtic Caucasians with Behçet's syndrome. The clinical features and HLA haplotypes are markedly different from 'Arab' and 'Japanese' varieties of Behçet's syndrome. The expression of the Dr4 and Dr7 antigens in those with gastrointestinal involvement possibly implicates class II antigens (Dr) in the pathogenesis of the manifestations of Behçet's disease in the bowel.

Data management of an inflammatory bowel disease registry

The history and etiology of inflammatory bowel disease which is characterized by two major disease processes: ulcerative colitis and Crohn's disease, remain unknown. Research is focussing on seven major areas of genetic, environmental and physiologic factors that apparently relate to this disease. Based on this background, a population based Inflammatory Bowel Disease Registry was established in 1987 in the Lehigh Valley area of southeastern Pennsylvania. Consent forms, patient data forms and protocols for operation and implementation were developed, and databases were designed to accommodate demographic, basic history, follow-up and relative history data. The databases were correlated with an IBD registry ID number which both enabled relational analyses and ensured confidentiality of data information. The registry continues to grow, providing feedback for both continued medical research and supportive information for IBD patients and their physicians.

Crohn's disease and nutrition

Malnutrition was included by Crohn as one of the features of the new disease he described. Most patients with Crohn's disease are malnourished even if their disease is not active. Nutritional factors may be implicated in the aetiology of the disease, but this remains unproven. The role of nutritional support and therapy is discussed and it is suggested that improving the patient's nutritional status may have a primary therapeutic as well as a supportive role in the treatment of the disease.

The effect of dietary yeast on the activity of stable chronic Crohn's disease

The effect of dietary yeast on the activity of stable Crohn's disease was assessed in 19 patients. During the 1st month patients continued their usual diet (base-line period), but during the next 2 months dietary yeast was excluded except that during 1 month patients took baker's yeast capsules while for the other month they took placebo capsules. The patients' mean Pettit Crohn's disease activity index (CDAI) while taking baker's yeast (mean, 107.9; SE, 6.1) was significantly greater than during yeast exclusion (mean, 102.1; SE, 5.7; p less than 0.05). The mean of each patient's maximum CDAI during yeast exclusion (mean, 107.1; SE, 5.7) was significantly lower than those during the base-line (mean, 115.2; SE, 6.1; p less than 0.05) and baker's yeast inclusion periods (mean, 113.9; SE, 6.7; p less than 0.05). Patients with elevated yeast antibodies tended to develop a higher CDAI while receiving baker's yeast (13 of 15). These results suggest that dietary yeast may affect the activity of Crohn's disease.

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.

Enteral feeding as sole treatment for Crohn's disease: controlled trial of whole protein v amino acid based feed and a case study of dietary challenge

A controlled trial was performed to compare enteral feeding with either an amino acid based feed or a whole protein feed as sole treatment for active Crohn's disease. Twenty four patients were studied (nine with ileal, 11 with ileocolonic, and four with colonic disease). Both feeds proved effective; nine of 13 patients randomised to receive the amino acid based feed were in clinical remission within three weeks as defined by a simple activity index compared with eight of 11 treated with the whole protein feed. Patients in clinical remission were then crossed over onto the other feed. None of the six patients who were changed to the whole protein feed relapsed over the subsequent three week period compared with three of seven patients who were changed to the amino acid based feed. In responders the median serum C reactive protein concentration fell from 21 mg/l (range 9-82) on entry to 6 mg/l (range 3-19) at six weeks. Seven patients relapsed within eight months of starting solid food (mean 3.7 months), while nine were still in remission (follow up period 3-9 months, median six months). Detailed studies of staged reintroduction of food and permitted food additives were carried out over a four year period in a patient with extensive stricturing small bowel Crohn's disease who had been brought into remission by open treatment with enteral feeding. Carrageenan, other permitted emulsifiers, bread, meat, potatoes, oranges, refined sugar, dairy produce, flour, and rice were all reintroduced without any objective ill effect, but green vegetables provoked a clinical and biochemical relapse within one week of introduction. Remission was rapidly achieved by switching back to the enteral feed but reintroduction of the low residue diet that had been previously tolerated produced a brisk relapse. Clinical and biochemical remission was again achieved by a return to the enteral feed but relapse again occurred with reintroduction of the low residue diet. These studies confirm the therapeutic effect of enteral feeding in Crohn's disease. This effect does not seem to be due to avoidance of whole protein, but the very low residue of chemically defined enteral feeds may be important, particularly in patients with intestinal strictures.

Crohn's disease and adenocarcinoma of the intestinal tract. Report of four cases

Four patients with intestinal adenocarcinoma complicating Crohn's disease are reported. The youngest of the four patients was a 21-year-old female with a 9-year history of Crohn's disease of the terminal ileum as well as of the entire colon. She developed mucus-producing moderately differentiated adenocarcinoma in the cecum. Of the remaining three patients with Crohn's disease, one presented an adenocarcinoma in the ascending colon, one in the rectum and the remaining one in the duodenum. All three colorectal adenocarcinomas originated in areas of high-grade dysplasia and all four in areas with chronic transmural inflammation. The review of the literature indicates that a total of 174 small and large bowel cancers occurring in Crohn's disease have been recorded (including the four reported herein). The vast majority of the reported cases have been found in the North American subcontinent. Only in a few instances were bowel adenocarcinoma and Crohn's disease observed in the European continent. It is therefore remarkable that three of our four cases were seen within a period of 12 months. Interestingly, six patients having colorectal adenocarcinoma in association with Crohn's disease were recently reported from a single hospital in England. The question therefore arises whether our cases and those reported recently from England are unrelated and merely coincidental or whether carcinomas are now also affecting European CD patients. If the latter is the case, the surveillance policy for patients with CD should be reconsidered at this hospital.

Spondylodiscitis and pseudarthrosis in a patient with enteropathic spondyloarthropathy

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Geographic variation of inflammatory bowel disease within the United States

One approach to learn about possible environmental risks in inflammatory bowel disease relates to studying its geographic pattern of occurrence. The geographic variation of inflammatory bowel disease within the United States was analyzed using the accumulated 17.5 million hospital discharges of all U.S. Medicare beneficiaries during two consecutive years. To validate the geographic pattern shown by the Medicare data, hospitalization was compared with mortality from inflammatory bowel disease among different states. Mortality and hospitalization statistics both suggested that the occurrence of inflammatory bowel disease was determined by environmental factors that had a marked geographic variation within the United States. Both Crohn's disease and ulcerative colitis appeared to be more frequent in northern parts of the United States than in southern and in urban more than rural parts. These trends were observed for men and women and for blacks and whites alike. Similar geographic patterns of Crohn's disease and ulcerative colitis suggested the influence of one or more identical risk factors for both diseases.

Mortality and causes of death in Crohn's disease. Review of 50 years' experience in Leiden University Hospital

Six hundred and seventy one patients (52.5% women) with Crohn's disease seen at Leiden University Hospital between 1934 and 1984 were identified. Follow up was 98.2% complete. Sixty four (9.7%) of the 659 patients died. The cause of death was related to Crohn's disease in 34 patients, probably related to the disease in four, and unrelated, from incidental causes, in 25. The cause of death could not be identified in one patient. There was a significant decrease of deaths related to the disease after 1973. Causes of death such as amyloidosis and malnutrition have disappeared and postoperative deaths have decreased. The standardised mortality ratio showed an excess mortality of 2.23 for all patients. It was higher for women (3.30) than for men (1.76). A comparison of two recent 10 year periods showed a significant decrease in standardised mortality ratio in men but not in women. Patients whose disease started before the age of 20 years had an excess mortality compared with older patients. This study supports the view that the prognosis of Crohn's disease has improved in general but high quality medical and surgical management is important particularly for younger patients.

Crohn's disease in black patients

Crohn's disease is less prevalent in blacks than in whites. However, when it does occur, it is associated with a high degree of morbidity and is frequently unrecognized at initial presentation. Forty-three patients with Crohn's disease presented to Howard University Hospital between 1965 and 1987. There were 156 hospital admissions, 47 emergency room visits, and 76 clinic visits over this 22-year period. Twenty-eight patients were female and 15 were male. The age of presentation for males ranged from 18 to 63 years and for females, 12 to 74 years. Crohn's disease should be considered in black patients who present with chronic abdominal pain and diarrhea. With correct diagnosis and appropriate medical therapy, patients should have an enhanced quality of life with less morbidity.

Occupational distribution of inflammatory bowel disease among German employees

Previous reports have shown that both Crohn's disease and ulcerative colitis affect people in white collar occupations associated with higher income and higher social class more frequently than other groups in the population. This study sought to carry these analyses one step further and investigate the distribution of inflammatory bowel disease by individual occupations. The German social security statistics for 'rehabilitation' were used to assess the occupational distribution of Crohn's disease and ulcerative colitis. From 1982 to 1988, a total of 12,014 people were granted rehabilitation as a result of inflammatory bowel disease. Low male prevalence of inflammatory bowel disease was found among bricklayers, road construction workers, unskilled workers in brick and stone, unskilled labourers, and security personnel. Low rates were found among women employed in cleaning and maintenance, and in those without occupation. In contrast, a high male prevalence was found among instrument makers, electricians, bakers, and technical assistants. Among female employees, inflammatory bowel disease was significantly associated with sales representatives, office workers, health occupations, and hairdressers. These associations were found in the complete data for 1982-8 as well as in the separate data for the two half periods 1982-5 and 1986-8. Highly significant correlations between the occupational distribution of Crohn's disease and ulcerative colitis were found among both male and female employees. It seems that occupations involving work in the open air and physical exercise are protective, while being exposed to air conditioned artificial working conditions or extended and irregular shift working confer a risk of contracting inflammatory bowel disease.

Crohn's disease in Northern Ireland--a retrospective study of 440 cases

The incidence of Crohn's disease in the community is thought to be changing, with conflicting evidence for increases, decreases or steady state situations being described. A retrospective study, using strict criteria for diagnosis, for a 16 year period in Northern Ireland demonstrated an increasing incidence of Crohn's disease, with a distribution in the population similar to that described in previous studies.

Immunosuppressive drugs in inflammatory bowel disease. A review of their mechanisms of efficacy and place in therapy

Immune effector mechanisms are central to the disease process in inflammatory bowel disease, but it is not clear whether the mucosal or systemic immunological abnormalities are primary phenomena, or are secondary to disease activity. Corticosteroid drugs remain the most effective treatment for active disease, but there is no evidence that they are useful for maintenance therapy. Some patients, however, are dependent on low-dose corticosteroids, and relapse when the drug is withdrawn. These drugs have widespread actions on the immune response, and monocytes are particularly sensitive to corticosteroids. In contrast, sulphasalazine and 5-aminosalicylic acid are effective in maintenance therapy, but do not act primarily by immunosuppressive mechanisms. They are effective in maintenance therapy of ulcerative colitis, and mild relapses of ulcerative colitis and colonic Crohn's disease. New preparations of 5-aminosalicylic acid have reduced side effects, many of which are due to sulphapyridine. Azathioprine and 6-mercaptopurine are used less widely: in Crohn's disease there is reasonable evidence for benefit in chronic active disease unresponsive to corticosteroids, and maintenance of remission. In ulcerative colitis, the position is less clearcut. Overall, trials favour an effect in chronic active disease, and there are pointers to an effect in maintenance of remission. Because of their side effects, in particular marrow suppression, these drugs should be reserved for second-line therapy. Similarly, other cytotoxic drugs are not used because of their side effects. More recently, cyclosporin A, with its selective action on interleukin-2 release and/or synthesis, and inhibition of helper T cell function, has been shown to be helpful in Crohn's disease. At present it should only be used in controlled trials, for patients with unresponsive disease in whom surgery is contraindicated. Renal toxicity may limit long term use. There is little data for cyclosporin A in ulcerative colitis. On the basis that there may be an underlying immune defect in Crohn's disease leading to mucosal inflammation, immunostimulant therapy has been used, but there is no evidence for benefit from treatment with BCG or levamisole in active disease or in maintenance therapy. 7S-Immunoglobulin, plasmapheresis or T-lymphocyte apheresis have been used in acute relapse, but evidence is anecdotal, and does not support their use except as a desperate measure to avoid surgery. Further well-designed controlled trials are needed to define the role of all these drugs, and further research into the mechanism of action on the immune response may shed light on the pathogenesis of inflammatory bowel disease.

Epidemiological study of asymptomatic inflammatory bowel disease: the identification of cases during a screening programme for colorectal cancer

An asymptomatic population of 37,000 people in the Nottingham area were offered faecal occult blood tests in a screening study for colorectal cancer. Seventeen thousand nine hundred and thirty people completed the tests and 481 individuals with positive tests underwent full investigation of the colon. Eight people with previously undiagnosed inflammatory bowel disease were identified. In five cases there was total ulcerative colitis; in one a proctitis and in two Crohn's disease. Two further patients with ulcerative colitis were identified; they had been lost to follow up for 25 and 45 years respectively. The combined prevalence of inflammatory bowel disease was 56/10(5) and it is likely that current studies of the epidemiology of these conditions may underestimate the true prevalence by between 27% and 38%.

Restriction fragment length polymorphism analysis of T-cell receptor genes in inflammatory bowel disease

The etiology of inflammatory bowel disease is still unknown, but autoimmune phenomena are thought to play an important role. However, only a weak association between HLA or immunoglobulin allotypes and inflammatory bowel diseases has been noted. Recently, DNA markers (restriction fragment length polymorphism (RFLP) pattern) of T-cell receptor gene allotypes have been reported and shown to be linked to susceptibility to autoimmune disease. We investigated the T-cell receptor RFLP pattern in inflammatory bowel diseases. No linkage to the constant region alpha- and beta-chain markers was observed, and no differences in the frequencies of 'genoallotypes' was found between patients and normal blood donors.

Risk factors in inflammatory bowel disease

A patient with inflammatory bowel disease may have several risk factors, including host defence and familial and environmental factors. Host defence factors include neutrophil and complement abnormalities and increased intestinal permeability. This may explain why elemental diets are effective treatment in Crohn's disease. Food is a major factor affecting the intestinal tract, and the considerable change in dietary habits during this century may explain why Crohn's disease has become more common. There is a geographic difference in the distribution of the disease. This could be due to difference in fish consumption. Fish oil has been shown to be effective in an uncontrolled study in the treatment of ulcerative colitis. This needs to be confirmed by ongoing controlled studies. Very few data have been published on the dietary habits of different countries. There is a need for a uniform dietary assessment that can be applied in a multicentre study. These studies would involve much co-operation but would yield important clues in the aetiology of inflammatory bowel disease.

Inflammatory bowel disease in migrant and native Jewish populations of southern Israel

Ulcerative colitis and Crohn's disease were studied in three Jewish populations in the Beer Sheva district of southern Israel. Age-adjusted prevalence rates on 31 December 1987 were for ulcerative colitis, 89/10(5), and for Crohn's disease, 30/10(5). Both diseases were commoner in females and in European-American-born Jews. Age-adjusted incidence rates have increased and in 1979-1987 were for ulcerative colitis, 5.4/10(5)/year, and for Crohn's disease, 2.1/10(5)/year. Females developed ulcerative colitis at a younger age and Crohn's disease at a later age than males. Israel-born patients developed both diseases at a young age. The clinical features of ulcerative colitis were similar in the various populations. Epidemiologic data in Jews may aid in the understanding of the pathogenesis of inflammatory bowel diseases.