The epidemiology of inflammatory bowel disease in Canada: a population-based study

BACKGROUND: Previously, we have demonstrated a high incidence and prevalence of Crohn's disease (CD) and ulcerative colitis (UC) in the Canadian province of Manitoba. However, the epidemiology of inflammatory bowel disease (IBD) in other regions of Canada has not been defined. The aim of this study was to estimate the incidence and prevalence of CD and UC in diverse regions of Canada and the overall burden of IBD in Canada. METHODS: We applied a common case identification algorithm, previously validated in Manitoba to the provincial health databases in British Columbia (BC), Alberta (AB), Saskatchewan (SK), Manitoba (MB), and Nova Scotia (NS) to determine the age-adjusted incidence rates per 100,000 person-years for 1998-2000 and prevalence per 100,000 for mid 2000 and to estimate the IBD burden in Canada. Poisson regression was used to assess differences in incidence rates and prevalence by gender, age, and province. RESULTS: The incidence rate for CD ranged from 8.8 (BC) to 20.2 (NS), and for UC ranged from 9.9 (BC) to 19.5 (NS). The prevalence of CD was approximately 15- to 20-fold higher than the incidence rate, ranging from 161 (BC) to 319 (NS). This was similar for the prevalence of UC, which ranged from 162 (BC) to 249 (MB). Adjusting for age and province, the female:male ratio for incidence ratio was 1.31 (p < 0.0001) for CD and 1.02 (n.s.) for UC and was mostly stable across the five provinces. CONCLUSIONS: Approximately 0.5% of the Canadian population has IBD. Canada has the highest incidence and prevalence of CD yet reported.     

Mortality in inflammatory bowel disease: a population-based cohort study

BACKGROUND & AIMS: There is no consensus regarding any increase in mortality with inflammatory bowel disease (IBD). In general, previous studies were not contemporary and were unable to correct for likely confounders. We have performed a large cohort study to examine contemporary IBD related mortality in the United Kingdom. METHODS: We selected subjects within the General Practice Research Database with a coded diagnosis of inflammatory bowel disease and up to 5 matched controls for each. We derived the date of recorded deaths and information on smoking and a variety of medical conditions. We calculated both the absolute risk of death and the relative risk as a hazard ratio corrected for available confounders by Cox regression. RESULTS: We included 16,550 IBD cases with 1047 deaths and 82,917 controls with 3758 deaths. The mortality rate was 17.1 per 1000 person-years overall for IBD cases and 12.3 for controls; this difference was greatest in the elderly. Conversion of these figures to hazard ratios by Cox regression gave hazard ratios of 1.54 (1.44-1.65) for all IBD, 1.44 (1.31-1.58) for ulcerative colitis (UC), and 1.73 (1.54-1.96) for Crohn's disease. The greatest hazard ratio for UC was among the 40-59-year age group (1.79 [1.42-2.27]) and for Crohn's disease among 20-39-year-olds (3.82 [2.17-6.75]). CONCLUSIONS: IBD is associated with an overall small increase in mortality rate greatest in relative terms in younger subjects but in absolute terms in the elderly.     

The clustering of other chronic inflammatory diseases in inflammatory bowel disease: a population-based study

BACKGROUND & AIMS: We aimed to discern the relative risk for several chronic inflammatory conditions in patients with ulcerative colitis (UC) and Crohn's disease. METHODS: We used the population-based University of Manitoba IBD Database that includes longitudinal files on all patients from all health system contacts identified by International Classification of Diseases, 9th revision, Clinical Modification codes for visit diagnosis. From the provincial database we extracted a control cohort matching the IBD patients 10:1 by age, sex, and geography. We considered a potential comorbid disease to be present if the patient had 5 or more health system contacts for that diagnosis. The comorbid disease period prevalence was analyzed separately for patients with UC and Crohn's disease and a prevalence ratio was calculated comparing the IBD populations with the matched cohort. RESULTS: There were 8072 cases of IBD from 1984 to 2003, including UC (n = 3879) and Crohn's disease (n = 4193). There was a mean of approximately 16 person-years of coverage for both patients and control patients. Both UC and Crohn's disease patients had a significantly greater likelihood of having arthritis, asthma, bronchitis, psoriasis, and pericarditis than population controls. An increased risk for chronic renal disease and multiple sclerosis was noted in UC but not Crohn's disease patients. The most common nonintestinal comorbidities identified were arthritis and asthma. CONCLUSIONS: The finding of asthma as the most common comorbidity increased in Crohn's disease patients compared with the general population is novel. These may be diseases with common causes or complications of one disease that lead to the presentation with another. Studies such as this should encourage further research into the common triggers in the organ systems that lead to autoimmune diseases.     

The prevalence of extraintestinal diseases in inflammatory bowel disease: a population-based study

OBJECTIVE: The aim of this study was to determine the prevalence of the major extraintestinal manifestations of inflammatory bowel disease (IBD) and their relation to disease diagnosis and gender. METHODS: We used the population-based University of Manitoba IBD Database, which includes longitudinal files on all subjects of all health system contacts identified by International Classification of Diseases, 9th Revision, Clinical Modification codes for visit diagnosis. We extracted a cohort from our database, which included subjects with a known diagnosis of IBD for at least 10 yr. We then determined how many contacts each subject had for each of the following extraintestinal IBD-associated immune diseases: primary sclerosing cholangitis, ankylosing spondylitis, iritis/uveitis, pyoderma gangrenosum, and erythema nodosum. We calculated the prevalence of the extraintestinal diseases using an administrative definition of having at least five health system contacts for the diagnosis in question. This administrative definition has previously been validated in Crohn's disease and ulcerative colitis (UC). RESULTS: A total of 6.2% of patients with IBD had one of six major extraintestinal diseases studied in this report. Only 0.3% of patients had multiple extraintestinal diseases. Iritis/uveitis was the most common extraintestinal disease of all assessed (2.2% of women and 1.1% of men). Iritis/uveitis was more common among women, particularly those with UC (3.8%). Primary sclerosing cholangitis was most common among men with UC (3%). Ankylosing spondylitis was more common among men, and the highest rate was seen among men with Crohn's disease (2.7%). Pyoderma gangrenosum was more common in Crohn's (1.2%) with no gender predilection. Erythema nodosum was similarly present in Crohn's and UC but was more common among women (1.9%). CONCLUSIONS: The associations of immune mediated diseases in extraintestinal sites may help us to further our understanding of IBD pathogenesis, and it may help us in developing a paradigm of disease subsets.     

The costs of early inflammatory joint disease: a population-based study in southern Sweden

OBJECTIVE: To study the costs and use of healthcare for patients during the first months with early joint inflammation, in a population-based prospective referral study in Southern Sweden. METHODS: Adult patients with arthritis for < 3 months and with onset of symptoms between 1 May 1999 and 1 May 2000 were referred from primary health centres to rheumatologists. Four clinical assessments were performed during a 6-month follow-up period. The direct medical costs for inpatient stays, outpatient visits, visits to general practitioners, and visits to health professionals, as well as costs for medication, radiographs, and laboratory tests were recorded from the onset of the disease up to 6 months of follow-up. Indirect costs for sick leave were also recorded. RESULTS: Fifty-six of 71 referred patients agreed to participate. Thirteen (23%) had RA, 21 (38%) had reactive arthritis (ReA), 14 (25%) had undifferentiated arthritis, and eight (14%) had other arthritides. The median cost per patient in the entire group was USD 3362. The median cost per patient in the RA group was USD 4385, and USD 4085 in the ReA group. There was no statistically significant difference in the median costs per patient in the different diagnostic groups. Sick leave accounted for 44% of the total costs in the entire group, and 46% and 47%, respectively, in the RA and ReA groups. CONCLUSION: The costs of early arthritis are already considerable during the first months of the disease following the onset of the symptoms. The indirect costs due to sick leave accounted for nearly half of the costs.     

Body composition in patients with inflammatory bowel disease: a population-based study

OBJECTIVE: Weight loss and nutritional depletion are common features of inflammatory bowel disease. Our aim was to assess body composition in patients with Crohn's disease (CD) and ulcerative colitis (UC) and to evaluate possible differences between the patient groups and healthy subjects. METHODS: A total of 60 patients with CD, 60 patients with UC, and 60 healthy subjects were investigated. Each group consisted of 24 men and 36 women. Body composition was measured by dual x-ray absorptiometry and Z scores were obtained by comparison to age- and sex-matched normal values. RESULTS: Bone mineral content and lean body mass were significantly lower in patients with CD compared with patients with UC and healthy subjects. The body composition of CD men was more strongly affected than that of women. UC patients had significantly higher fat mass and body mass index than patients with CD and healthy subjects. There was no difference in the percentage of fat mass between the two patient groups. Corticosteroid treatment and smoking had a negative impact on bone mineral content and lean body mass in CD patients independently of each other. CONCLUSIONS: CD was associated with disturbances in body composition: both bone mineral content and lean body mass were significantly reduced, especially in men with CD. Corticosteroid therapy and smoking had a significant influence on body composition in patients with CD. When studying the effects of inflammatory bowel disease on body composition and nutritional status, patients with CD and UC should be evaluated separately.     

The natural history of corticosteroid therapy for inflammatory bowel disease: a population-based study

BACKGROUND & AIMS: The aim of this study was to determine the 1-year outcome after the first course of corticosteroids in an inception cohort of patients with inflammatory bowel disease. METHODS: All patients in Olmsted County, Minnesota, diagnosed with Crohn's disease (n = 173) or ulcerative colitis (n = 185) from 1970 to 1993 who were treated with systemic corticosteroids were identified (4 denied research authorization). Immediate outcome (30 days) and 1-year outcome after the first course of corticosteroids were determined. RESULTS: Seventy-four (43%) patients with Crohn's disease and 63 (34%) with ulcerative colitis were treated with corticosteroids. Immediate outcomes for Crohn's disease were complete remission in 43 (58%), partial remission in 19 (26%), and no response in 12 (16%). Immediate outcomes for ulcerative colitis were complete remission in 34 (54%), partial remission in 19 (30%), and no response in 10 (16%). One-year outcomes for Crohn's disease were prolonged response in 24 (32%), corticosteroid dependence in 21 (28%), operation in 28 (38%), and lost to follow-up in 1 (1%). One-year outcomes for ulcerative colitis were prolonged response in 31 (49%), corticosteroid dependence in 14 (22%), and operation in 18 (29%). CONCLUSIONS: Most patients with Crohn's disease and ulcerative colitis initially respond to corticosteroids. At 1 year, 32% of patients with Crohn's disease and 48% with ulcerative colitis are corticosteroid free without operation.     

Genetic epidemiology in inflammatory bowel disease

Family studies of different designs have been carried out in the last few years. Five to ten percent of patients have another case of inflammatory bowel disease (IBD) among their first-degree relatives, with about 75-80% concordance for the same disease within the family. About 20% of multi-affected families present both cases with ulcerative colitis and Crohn's disease. The population relative risk in first-degree relatives of patients show a 14-15 times higher prevalence of IBD. Prevalence values of 1.5-3.5% in first-degree relatives have been found, with an even higher calculated lifetime risk especially in offspring and siblings of patients with IBD. Earlier disease onset in offspring of patients with IBD have consistently been found, and genetic anticipation has been hypothesized. The phenomenon, however, may be a result of a combination of a time trend - increasing the incidence of Crohn's disease - and the fact that patients with early onset of IBD may have lower fertility and therefore may be underrepresented in the parent-child pairs studied. Twin studies have shown significantly higher concordance rates in monozygotic than in dizygotic twins. Further, the concordance rate in monozygotic twins is higher in Crohn's disease than in ulcerative colitis, indicating a stronger genetic influence in this condition. Disease course and prognosis within families have been studied without convincing concordance found in this respect among family members.     

The epidemiology of inflammatory bowel disease: East meets west

The incidence of inflammatory bowel diseases (IBD) in East has risen over the past decade to become a global disease. The increasing number of studies on the incidence and course of IBD in East has enabled us to explore East versus West differences in the epidemiology of IBD which could enhance our understanding of the heterogeneity of the disease and eventually assist in the discovery of novel therapeutic targets and design of preventive strategies. Comparison of population-based data in East and West reveals that the incidence of IBD has risen rapidly in East while plateauing in West. Furthermore, the clinical presentation and course of IBD differs between East and West with more patients in East presenting with complicated disease. Considering the scarcity of population-based data from East and the lack of studies with long durations of follow-up, it remains to be clarified whether these differences reflect true differences in disease presentation. The effects of genetic and environmental risk factors contributing to IBD also differ between Eastern and Western populations. Considering the differential effects of genetic and environmental risk factors in East and West, future studies should seek to discover novel genetic and environmental risk factors which might specifically apply to eastern populations. In this narrative review, we compare the epidemiology of IBD between eastern and western countries by summarizing evidence from population-based cohort studies in the last ten years. Furthermore, we look at differences in genetic susceptibility and environmental triggers of IBD between East and West.     

The incidence of inflammatory bowel disease in a rural region of Southern Germany: a prospective population-based study

OBJECTIVE: Although important advances in understanding the aetiology and pathogenesis of inflammatory bowel disease (IBD) have been made, many questions remain unanswered. As the most recent data available on the incidence of IBD in Germany were collected about 15 years ago, we set up a new population-based cohort to determine current incidence data for a defined region in Germany and to establish a basic cohort for prospective follow-up. METHODS: All patients living in the region of Oberpfalz newly diagnosed with IBD between 1 January 2004 and 31 December 2006 were included in this study by setting up a network of reporting clinicians and general practitioners in hospitals as well as in private practices. Demographic and clinical characteristics such as age at first diagnosis, localization of the disease, extraintestinal manifestations or family history on IBD were documented. Age-adjusted incidence rates are presented with 95% Poisson confidence intervals (CIs), based on the European standard population. RESULTS: In total, 286 newly diagnosed patients with IBD were reported in this region, 168 patients suffering from Crohn's disease (CD), 105 patients with ulcerative colitis. Age-standardized incidence rates were 11.0/10(5) (95% CI: 9.1-11.6) for IBD, 6.6/10(5) (95% CI: 5.6-7.7) for CD and 3.9/10(5) (95% CI: 3.2-4.7) for ulcerative colitis. Peak incidences were found in the age interval of 16-24 years for both diseases, predominantly for CD. Age at first diagnosis was lower, extraintestinal manifestations and a positive family history on IBD were more common in patients with CD. CONCLUSION: The incidence rate in IBD seems to be stable in Germany as compared with previously reported data, as is the remarkable predominance of CD. Prospective follow-up studies will be based on this incidence cohort.     

Risk of intestinal cancer in inflammatory bowel disease: a population-based study from olmsted county, Minnesota

BACKGROUND & AIMS: The risk for colorectal cancer in Crohn's disease and ulcerative colitis patients from the United States currently is unknown. We estimated the risk for small-bowel and colorectal cancer in a population-based cohort of 692 inflammatory bowel disease patients from Olmsted County, Minnesota, from 1940 to 2001. METHODS: The Rochester Epidemiology Project was used to identify cohort patients with colorectal and small-bowel cancer. The cumulative probability of cancer and standardized incidence ratios (SIR) were estimated using expected rates from Surveillance, Epidemiology, and End Results, white patients from Iowa, from 1973 to 2000, and Olmsted County, from 1980 to 1999. RESULTS: Colorectal cancer was observed in 6 ulcerative colitis patients vs 5.38 expected (SIR, 1.1; 95% confidence interval [CI], 0.4-2.4), but 4 of these occurred among those with extensive colitis or pancolitis (SIR, 2.4; 95% CI, 0.6-6.0). Six Crohn's disease patients (vs 3.2 expected) developed colorectal cancer (SIR, 1.9; 95% CI, 0.7-4.1). Three Crohn's disease patients developed small-bowel cancer vs 0.07 expected (SIR, 40.6; 95% CI, 8.4-118). CONCLUSIONS: The risk for colorectal cancer was not increased among ulcerative colitis patients overall, but appeared to be increased among those with extensive colitis. The colorectal cancer risk was increased slightly among Crohn's disease patients, who also had a 40-fold excess risk for small-bowel cancer.     

Outcomes of infants born to mothers with inflammatory bowel disease: a population-based cohort study

OBJECTIVE: Limited population-based data on inflammatory bowel disease (IBD) and pregnancy outcomes exist. The purpose of this study is to determine the association between maternal IBD status and adverse pregnancy outcomes. METHODS: Using computerized birth records of infants born to mothers with Crohn's disease (CD) or ulcerative colitis (UC) and mothers without diagnoses of IBD (no-IBD) in Washington State, we performed a cross-sectional retrospective study to determine gestational age, birth weight, and congenital malformations. RESULTS: Preterm delivery was seen in 15.2% of CD births, 10.4% of UC births, and 7.2% of no-IBD births. Low birth weight was found in 16.8% of CD births, 7.6% of UC births, and 5.3% of no-IBD births. Smallness for gestational age was present in 15.2% of CD births, 10.5% of UC births, and 6.9% of no-IBD births. Only CD births were at significantly increased risk of preterm delivery (p < 0.0025), low birth weight (p < 0.001), and smallness for gestational age (p < 0.001). Congenital malformations were more commonly recorded in UC births than in controls (7.9% vs 1.7%, p < 0.001), whereas 3.4% of CD births had malformations recorded. Using multivariable logistic regression, CD births were more likely to be preterm (odds ratio [OR] = 2.3, 95% CI = 1.4-3.8) and have low birth weights (OR = 3.6, CI = 2.2-5.9) and smallness for gestational age (OR = 2.3, CI = 1.3-3.9). UC births were more likely to have congenital malformations reported (OR = 3.8, CI = 1.5-9.8). CONCLUSIONS: Maternal IBD is associated with increased odds of preterm delivery, low birth weight, smallness for gestational age (CD), and reporting of congenital malformations (UC).     

Childhood growth and risk of inflammatory bowel disease: a population-based study of 317,030 children

Background: Growth in childhood is associated with later development of autoimmune diseases and cancer, but the impact of growth on risk of inflammatory bowel disease (IBD) remains unknown. We conducted a population-based cohort study to examine whether birth weight, childhood height, or changes in height associated with later risk of IBD.

Methods: Our cohort consisted of 317,030 children from the Copenhagen School Health Records Register (born 1930–1989) with height repeatedly measured from age 7 to 13 and with data on birth weight on a subset. Through linkage to the Danish National Patients Register, cases of IBD were identified. Cox proportional hazard regression was used to examine associations between measures of childhood growth and risk of IBD.

Results: During more than 9 million years of follow-up, 1612 individuals were diagnosed with Crohn’s disease (CD) and 2,640 with ulcerative colitis (UC). Birth weight and childhood heights were not associated with subsequent risk of CD or UC (HRs close to 1.00). Childhood growth from 7 to 10 years (CD: HR, 1.00; 95% CI, 0.85–1.18; UC: HR, 0.92; 95% CI, 0.81–1.05) and 10 to 13 years (CD: HR, 1.02; 95% CI, 0.89–1.17; UC: HR, 0.95; 0.85–1.05) did not associate with risk of IBD either.

Conclusion: In this large population-based cohort study, birth weight and childhood growth did not influence risk of IBD, which contrasts with observations in other chronic diseases. Thereby, the study also suggests that pre-clinical effects of adult IBD are not measurable in childhood and that childhood risk factors for IBD do not influence growth.     

Clinical epidemiology of inflammatory bowel disease in Lebanon

BACKGROUND: The objectives of this study were to determine the prevalence and incidence of inflammatory bowel disease (IBD) in a representative Lebanese cohort and to describe practice prevalence trends, disease characteristics, and impact on quality of life (QoL) of IBD patients in Lebanon. METHODS: All of a university-based health program's 2000-2004 computerized records that listed a diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) were reviewed. In addition, data on patients seen in the gastroenterology clinics and data from the IBD registry at the American University of Beirut Medical Center (AUBMC) from the same period were analyzed. RESULTS: Of 15,073 insured individuals, 8 had a diagnosis of CD and 16 of UC, giving an age-adjusted prevalence of 53.1 per 100,000 people for CD and 106.2 per 100,000 people for UC. The mean age at diagnosis for patients with CD and UC was 28.8 +/- 11.1 and 32.0 +/- 13.4 years, respectively, and there was a slight female predominance. The mean annual incidence was 4.1 per 100,000 people for UC and 1.4 per 100,000 people for CD (range, 0-6.9/100,000 for both). Of the 10,383 patients seen in the gastroenterology clinic from 2000 to 2004, 251 (2.4%) had IBD (142 UC, 100 CD, and 9 indeterminate), a ratio that trended upward over time (range, 1.8%-2.7%). The median IBD Quality-of-Life (IBDQ) questionnaire score was 124.9 +/- 30.5, indicating that the disease had a moderately severe impact on QoL. CONCLUSIONS: The prevalence of IBD in this representative Lebanese cohort falls in the intermediate range of that reported for white populations in Europe and North America. Future studies are needed to examine local risk factors, disease genotypes and phenotypes, and epidemiologic time trends. The psychosocial burden of IBD in Lebanon appears significant.