American Journal of Gastroenterology ISSN 0002-9270C© 2007 by Am. Coll. of Gastroenterology doi: 10.1111/j.1572-0241.2007.01124.xPublished by Blackwell Publishing

Inflammatory Bowel Disease in the South Asian PediatricPopulation of British ColumbiaVared Pinsk, M.D.,2 Daniel A. Lemberg, M.D.,2 Karan Grewal,2 Collin C. Barker, M.D.,2 Richard A. Schreiber,M.D.,2 and Kevan Jacobson, M.D.1,2,3

1Children and Family Research Institute, 2Division of Gastroenterology, B.C. Children’s Hospital, Vancouver,British Columbia, Canada; and 3Department of Cellular and Physiological Sciences, University of BritishColumbia, Vancouver, British Columbia, Canada

BACKGROUND: Geographical differences, population migration, and changing demographics suggest anenvironmental role in prevalence, modulation, and phenotypic expression of inflammatory boweldisease (IBD).

AIM: To determine the incidence of IBD and disease subtype in the pediatric South Asian population inBritish Columbia (BC) compared with non-South Asian IBD patients in the same geographic area.

METHODS: Chart review with data collected for all patients ≤16 yr of age diagnosed with IBD at B.C. Children’shospital, January 1985 to June 2005. Age, gender, family history, duration of symptoms, type, andextent of disease were extracted. Identified South Asian subjects were prospectively interviewed.

RESULTS: Seventy-five South Asian patients were diagnosed with IBD, 48% Crohn’s disease (CD), 33.3%ulcerative colitis (UC), and 18.7% with indeterminate colitis (IC), in contrast to 71%, 18.8%, and10.2%, respectively, in the non-South Asian population. The incidence rate for South Asian IBDpatients, for the period 1996–2001 was 15.19/105 (6.41/105 for CD, 6.70/105 for UC, and2.08/105 for IC) compared with 5.19/105 for the non-South Asian IBD group (3.69/105, 0.96/105,and 0.54/105, respectively). The South Asian male/female ratio was significantly different from thatobserved for the rest of the population.

CONCLUSION: These data suggest a significantly higher incidence of IBD in the South Asian pediatric populationcompared with the rest of the BC pediatric population, with a different pattern of phenotypicexpression, a male predominance, and more extensive colonic disease. These data suggest apotential effect of migration, and environmental and lifestyle change on the incidence of IBD anddisease subtype.

(Am J Gastroenterol 2007;102:1077–1083)

BACKGROUND

Crohn’s disease (CD) and ulcerative colitis (UC) are chronicintestinal inflammatory bowel diseases of unknown etiologythought to be precipitated by interactions between the genet-ically susceptible host, the mucosal immune system, and theenvironment. While studies have focused on the intestinalimmune system and intestinal microbiota, external envi-ronmental factors have received less attention. However,epidemiological studies of the diseases suggest that extrin-sic environmental factors may play an important role in theprevalence, modulation, and phenotypic expression of thediseases (1).

Inflammatory bowel disease (IBD) in adults is consid-ered to be relatively common in Northern Europe and NorthAmerica (2–4) whereas in Asia and Southern and EasternEurope, the incidence rates are much lower (4–6). Presently,insufficient data are available in pediatric IBD to determine

whether a similar geographical distribution occurs. SeveralEuropean pediatric studies, using various methodologies,have reported incidence rates ranging from 0.7 to 4.3/105

for UC, 0.7 to 8.4/105 for CD, and 0 to 3.6/105 for indetermi-nate colitis (IC) (7). A recent North American study from thestate of Wisconsin reported incidence rates of 2.1/105 for UCand 4.68/105 for CD. In this study, no difference in incidencerates for IBD was observed among various ethnic groups (8).

Immigration provides an opportunity to study the associ-ation between environmental and lifestyle changes and theirimpact on the expression of IBD. To date, few epidemiologi-cal studies have investigated IBD in immigrant populations.Studies by Probert et al. have demonstrated a higher inci-dence of UC among South Asian adult immigrants in Le-icester compared with the indigenous European population(9, 10). Furthermore, young Asians born in Britain werefound to be at higher risk of developing IBD than the in-digenous European population (11). In a prospective survey

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of childhood IBD in the British Isles, those children of Asianbackground were overrepresented and more likely to have UC(12). In contrast, a more recent study in children with IBD inEast London observed an equal proportion of CD and UC/ICamong Bangladeshi children and Caucasian children (13).These data suggest that migration, environmental changes,and changing lifestyles may have long-lasting effects on in-cidence and expression of IBD.

Canada, and especially British Columbia (BC), has expe-rienced a demographic shift over the last 20 yr with the influxof immigrants from various geographic locations includingEast and South Asia (Statistics Canada, 2001 Census (14)).In Canada, no epidemiological study has been undertakento examine the incidence of IBD in the South Asian immi-grant population. British Columbia’s Children’s Hospital isuniquely positioned as a center to examine pediatric IBD epi-demiology as it is the only pediatric tertiary-care hospital inthe province with all provincial pediatric gastroenterologistspracticing at this site.

The aim of the present study was to examine the clinicalcharacteristics of IBD in the South Asian pediatric popu-lation of BC diagnosed with IBD at British Columbia Chil-dren’s Hospital (BCCH) between 1985 and 2005. In addition,incidence rates of IBD for the period 1996 and 2001 were de-termined with comparison to the non-South Asian pediatricIBD population of BC.

MATERIALS AND METHODS

PopulationThe total BC population in 1996 and 2001 was 3,724,500and 3,907,740, respectively. Children ≤16 yr accounted for21.7% and 20.8% of the population, respectively (810,078and 815,145 individuals). Children, 16 yr of age and under,of South Asian descent, whose families originated from India,accounted for 4.2% and 5.4% of the population, respectively(33,627 and 44,200 individuals). While the total populationand the total pediatric population of BC (≤16 yr of age) re-mained relatively stable between years 1996 and 2001, thetotal South Asian population of BC increased dramaticallyby approximately 33%, (Statistics Canada, 1996 and 2001Census (14)) making it difficult to estimate the size of theSouth Asian pediatric population of BC for the years after2001. For this reason, the incidence of IBD in the study pop-ulation was determined for the period 1996–2001 and com-pared with the last population-based figures obtained fromStatistics Canada.

Case IdentificationA retrospective review was undertaken with data collectedfrom medical charts of South Asian pediatric patients ≤16yr of age diagnosed with IBD at BCCH between 1985 andJune 2005. Only South Asian patients whose families origi-nated in including those who migrated to Africa/Europe andthen Canada were included in the study group. Data collectedincluded date of birth, gender, ethnicity, religion, family his-tory of IBD, duration of symptoms prior to diagnosis, date of

diagnosis, age at diagnosis, type, and extent of disease. All pa-rameters were compared with non-South Asian IBD patientsdiagnosed at BCCH over the same period, with informationobtained solely from the BCCH Pediatric IBD database (15).

A questionnaire interview was prospectively undertakenin the outpatient clinic, or by telephone. The identificationof South Asian origin obtained from medical charts was con-firmed in 90% of cases. Patients diagnosed at BCCH and whohad graduated to adult care were included in the cohort. Sevenpatients were unavailable either because of missing personaldetails (five patients) or were lost to follow-up (two patients).Patients and their parents were interviewed to obtain addi-tional details regarding gender, ethnic background, patient’s,parent’s, and grandparent’s country of birth, urban or ruralliving in country of origin, religion, and family history ofIBD. A second part of the questionnaire included questionson breast feeding/formula feeding and duration, smoking his-tory (active or passive) and duration, and whether a grand-parent lived with the family in Canada. The dietary question-naire included frequency of food servings from all four foodgroups and sweets consumed/day over a period of 1 wk. Foodportions were determined using definitions provided by theHealth Canada Food Guide (16) and where necessary pic-tures of food portions were provided. A Punjabi adaptationof Canada’s Food Guide to Healthy Eating was included toensure that each food group was appropriately classified (17).

While the standard diagnostic approach at BCCH variedslightly between gastroenterologists over this period, all orpart of the following diagnostic workup, including esoph-agogastroduodenoscopy (EGD), colonoscopy, and contrast-enhanced radiological studies, was included when makinga diagnosis. Two separate gastroenterologists reviewed eachchart and in cases when there was disagreement regardingdisease type, a third gastroenterologist was involved. Thediagnosis of IBD was made according to standard clinical,radiological, endoscopic, and histological criteria (7, 18).

CD was diagnosed when there was evidence of perianal dis-ease (skin tags, abscess, fistula), endoscopic findings of skiplesions, cobblestone appearance, mucosal ulceration (snailtract, serpigenous) on colonoscopy, and/or mucosal abnor-mality at upper endoscopy (aphthous ulceration) with histo-logical findings of focal/segmental inflammation, deep in-flammation, noncaseating granuloma, or chronic terminalileal inflammation with or without radiological evidence ofskip lesions, stricturing disease, fistulizing disease, or smallintestinal involvement.

UC was defined as continuous disease of the colon withvariable proximal extension from the rectum with histolog-ical findings confirming rectal involvement, contiguous in-flammation, superficial inflammation, crypt abscess, crypti-tis, and no evidence of small bowel involvement, other thanbackwash ileitis. The presence of nonspecific gastritis did notrule out a diagnosis of UC.

IC was defined as the absence of small bowel involvementafter ileal intubation and radiologic evaluation, an inconclu-sive endoscopic appearance, and histological features that

Epidemiology of IBD in a Pediatric South Asian Population 1079

were specifically diagnostic of neither CD or UC, but includedactive and patchy chronic inflammation with minimal or mod-erate architectural distortion (19). Other causes of colitis,including infectious, eosinophilic, or lymphocytic colitis,were excluded.

Ethical approval for the study was obtained from the Uni-versity of British Columbia Clinical Research Ethics Boardand the British Columbia Children’s and Women’s ResearchReview Committee. Consent forms and questionnaires wereprovided in both English and Punjabi.

StatisticsPopulation estimates and population characteristics includ-ing age, sex, ethnicity, and geographical location were ob-tained from Statistics Canada, special tabulation, unpublisheddata (2001 Census) and Statistics Canada, community pro-files, catalogue no. 97F0003XCB2001001, provincial Census1996 and 2001 (14). Descriptive statistics were generated andodds ratios were calculated for the target variables. All statis-tical analyses were performed using the Statistical Packagefor Social Sciences (SPSS Inc., Chicago, IL, Version 13 forWindows).

RESULTS

A total of 75 pediatric South Asian patients were diagnosedwith IBD during the study period from January 1985 to June2005 compared with 504 pediatric non-South Asian IBDpatients diagnosed during the same period. The Caucasianpopulation accounted for 80% of the non-South Asian IBDpopulation with the remainder consisting of various ethnicminorities. Thirty-six South Asian patients (48%) were diag-nosed with CD, 25 (33.3%) with UC, and 14 (18.7%) withIC, (Table 1). In contrast, 361 (71%) non-South Asian pa-tients were diagnosed with CD, 95 (18.8%) with UC, and 48(10.2%) with IC. Of the 75 South Asian patients diagnosedover the 20-yr period, 66 patients (88%) were diagnosed from1996 to 2005. During this period we observed a 6.25-fold in-

Table 1. Gender, Generation, and Religion of Pediatric South AsianIBD patients

Disease Subtype

Total Population CD UC ICN = 75 (N = 36) (N = 25) (N = 14)

GenderMale/Female 50/25 28/8 15/10 7/7

GenerationFirst 5 3 1 1Second 63 30 22 11N/A 7 3 2 2

ReligionSikh 59 28 19 12Muslim 8 3 5 0Hindu 3 1 1 1N/A 5 4 0 1

Total population = total number of South Asian IBD patients; CD = Crohn’s disease;UC = ulcerative colitis; IC = indeterminate colitis; N/A = not available.

Figure 1. Cumulative number of South Asian IBD patients diag-nosed at BCCH each year between 1995 and 2005 with Crohn’sdisease (CD), ulcerative colitis (UC), and indeterminate colitis (IC).

crease in the number of South Asian patients diagnosed withUC and a sixfold increase in the number of patients diagnosedwith CD (Fig. 1).

The average incidence rate for IBD between 1996 and 2001for the South Asian pediatric population was substantiallyhigher than that observed for the non-South Asian pediatricIBD population with incidence rates of 15.19/105 children peryear (range 5.95/105 in 1996 to 18.01/105 for 2001) comparedwith 5.19/105 children per year (range 4.44/105 in 1996 to7.73/105 for 2001), respectively (Fig. 2). For the South AsianIBD population, the average incidence rates for CD, UC, andIC were 6.41/105, 6.70/105, and 2.08/105 children per year,respectively, compared with 3.69/105, 0.96/105, and 0.54/105

children per year for the non-South Asian IBD population(Fig. 2).

We observed a male predominance in the South Asian IBDpopulation (Table 1) and the male/female ratio was signifi-cantly higher than that observed for the non-South Asian IBDpopulation (2:1 vs. 1.1:1, OR 1.8, 95% CI 1.1–3.0).

The median age at diagnosis of IBD in the South Asianpopulation was 132 months, with a range of 43–192 months,which was not significantly different from the age at diagnosis

Figure 2. Average incidence rates of IBD for the South Asian andnon-South Asian pediatric populations of BC between the years1996 and 2001.

1080 Pinsk et al.

Table 2. Median Age at Diagnosis (Months) for South Asian and Non-South Asian IBD Patients

IBD Population CD UC ICMedian Age Median Age Median Age Median Age

(N) (Range) in Months (N) (Range) in Months (N) (Range) in Months (N) (Range) in Months

South Asianpopulation

All 75 134 (43–192) 36 150 (59–192) 25 133 (73–192) 14 120 (43–170)Male 50 142 (43–192) 28 150 (59–191) 15 149 (93–192) 7 124 (43–170)

Female 25 118 (51–192) 8 164 (91–192) 10 108 (73–180) 7 75 (51–135)Non-South Asian

populationAll 504 143 (10–192) 364 147 (10–192) 93 129 (15–192) 47 112 (12–191)

Male 266 145 (12–192) 206 148 (18–192) 39 142 (15–192) 21 91 (12–191)Female 238 139 (10–192) 158 144 (10–192) 54 128 (35–192) 26 122 (17–174)

IBD = inflammatory bowel disease; Total = total number of South Asian and non-South Asian IBD patients; CD = Crohn’s disease; UC = ulcerative colitis; IC = indeterminate colitis.

of the non-South Asian IBD patients (Table 2). South Asianfemale IBD patients with UC and IC tended to be diagnosedat a younger age than their male counterparts. In contrast,South Asian female patients with CD tended to be diagnosedat an older age, with a median age at diagnosis of 164 monthscompared with 108 months for UC and 75 months for IC(none of these differences reached statistical significance).

While the duration of symptoms prior to the diagnosis wasquite variable among the IBD population, patients with UCwere generally diagnosed sooner. Interestingly, the medianduration of symptoms prior to diagnosis for each disease sub-type among the South Asian population was shorter than thatobserved for the non-South Asian group (Table 3). SouthAsian patients had more extensive colonic disease, with 68%(48/71) of patients demonstrating pancolitis compared with46% (214/465) of non-South Asian patients (OR 2.45, 95%CI 1.44–4.16). This difference was more marked in patientswith CD, where pancolonic involvement was observed in72% (23/32) of South Asian patients compared with 43%(139/325) of non-South Asian patients (OR 3.42, 95% CI1.54–7.62). All five first-generation South Asian patients hadpancolitis, in contrast to 64% of second-generation patients(CD 19/29, UC and IC 23/37).

A family history of IBD was evident in 35% of South Asianpatients, which was not significantly different from that ob-served in the non-South Asian IBD population (37%). Nofirst-degree South Asian relatives had CD, and only 22% ofsecond-degree relatives had CD, with the remainder diag-nosed with UC or IC. In children with a family history ofUC and IC, 5 of 11 were diagnosed with CD. All first-degreeSouth Asian relatives were older than the study population

Table 3. Duration of Symptoms (Months) for South Asian and Non-South Asian Patients Prior to Diagnosis of IBD

South Asian Population Non-South Asian Population

(N) Total (75) CD (36) UC (25) IC (14) Total (496) CD (360) UC (91) IC (45)Median (months) 2.00 2.00 2.00 5.00 4.00 5.00 3.00 8.00Range (months) 0.5–48 0.5–48 0.5–7 1–36 0.5–96 0.5–96 0.5–36 0.5–60Mean 5.50 6.33 2.50 8.64 8.50 8.90 5.10 13.40SD 8.24 9.61 1.87 10.09 11.60 11.99 6.35 15.30

Total = total number of IBD patients with colonic involvement; CD = Crohn’s disease; UC = ulcerative colitis; IC = indeterminate colitis.

and most of these individuals were first-generation immi-grants.

The majority of South Asian patients were born in Canada(Table 1). At diagnosis, 85% of children were living in urbanareas. The first/second-generation immigrant ratio among theSouth Asian IBD patients was 1:12.6 compared with 1:5.5 forthe total South Asian population of BC 16 yr of age and be-low (OR 2.3, 95% CI 0.9–5.7). Most of the patients’ families(84%) originating from the Punjab area immigrated directlyto BC, whereas 16% of the families were either born else-where in India and/or immigrated first to Africa or Englandand then to Canada. Seventy-nine percent of patients wereSikh, 11% Muslim, and 4% Hindu. In 6% of patients thereligious affiliation was unknown (Table 1).

Forty patients (53%) together with a parent completed thequestionnaire. Seventy percent of respondents indicated thattheir families emigrated from rural to urban communities,with the remainder of families migrating from urban to ur-ban (20%) or urban to rural (10%) communities. Sixty-ninepercent of patients were breast fed (56% for more than 6months), in contrast to 92% of parents (80% breast fed formore than 6 months). Forty-two percent of patients lived to-gether with a grandmother in the same house. It appearedthat this arrangement had limited influence on the diet of thechild. Where a traditional diet was consumed by grandpar-ents, 70% of parents consumed a traditional diet at least 67%of the time, and half of patients less than 50% of the time.Consumption of a strict vegetarian diet was reported in 30%of parents and 15% of patients.

With the exception of one female South Asian UC patientwho reported a current smoking history, all other patients,

Epidemiology of IBD in a Pediatric South Asian Population 1081

parents, and household family members denied a past or cur-rent history of cigarette smoking.

DISCUSSION

To our knowledge, this is the first study to describe the in-cidence and clinical characteristics of IBD in a South Asianpediatric population residing in North America. The averageincidence rate for IBD in this population from 1996 to 2001was 15.19/105, which is among the highest incidence ratesreported in the pediatric literature. The incidence rate was 2.9-fold higher than that observed for the rest of the BC pediatricIBD population, and was approximately twofold higher thanWisconsin children (8) and 1.4–4-fold higher than pediatricEuropean populations (7). No data are currently available forcomparison with pediatric IBD populations of India. In con-trast, a prospective study in an adult population in the Punjabarea (where the majority of our patients originate) has pro-vided a crude incidence rate of 6.02/105 for UC, but no dataare available for CD (20).

Consistent with published data, (9, 10) our study demon-strated increasing numbers of South Asian patients diagnosedwith IBD over time, with incidence rates increasing from5.95/105 in 1996 to 18.01/105 in 2001. Furthermore, our datasuggest that the number of South Asian children diagnosedwith IBD each year continues to increase (Fig. 1).

In keeping with adult South Asian IBD studies in theBritish Isles (9, 10), the present study demonstrated a higherincidence of UC in South Asian compared with non-SouthAsian pediatric populations of BC. However, in contrast toinfrequent reporting of adult CD in India (20), and predomi-nance of UC in the South Asian IBD population in the BritishIsles (9, 10, 12), our study demonstrated that South Asianchildren were more likely to have CD. Previous studies inmost westernized countries have demonstrated a gradual in-crease in CD cases from the 1960s through the 1990s, re-sulting in the CD incidence surpassing UC incidence (21,22). Furthermore, studies from Japan showed an initial pre-dominance of UC followed by a rise in CD approximatelyone decade later (6). An increasing incidence of CD hasalso been observed in Bangladeshis in East London, wherethe age-standardized incidence of CD increased from 2.3to 7.3/105 between 1981–1989 and 1997–2001 (23). More-over, a recent study in children with IBD from East Lon-don demonstrated an equal proportion of CD and UC/ICamong Bangladeshi children and Caucasian children (13).Additionally, CD is now being increasingly recognized inIndia (24).

Explanations for the higher incidence of disease and differ-ences in disease subtype remain to be determined but likelyinvolve both genetic and environmental factors. The low inci-dence of CD in India is likely an underestimation of diseasedue limitations of access to health care, limited availabil-ity of diagnostic technology, and confusion with abdominaltuberculosis (24). On the other hand, the incidence of IBD

as a whole in developing countries is postulated to be lowas a result of poor sanitation and hygiene, and exposure tonumerous infectious stimuli in childhood (25–27). However,evidence for the hygiene hypothesis in the etiology of IBDremains unclear. A recent North American study of pediatriconset CD in a tertiary-care center in Montreal, Canada, sug-gests that infection-related exposures may actually enhancerisk for childhood CD, although timing of infection duringchildhood may be the critically important (28). Nevertheless,improving sanitation and hygiene and westernization of thediet are likely important factors contributing to the emer-gence of CD in India (24) and probably play a role in theincreasing preponderance of CD in South Asian children ofBC.

The response to the dietary questionnaire was obtainedin 53% of patients, possibly limiting generalizability of thedata to the entire cohort. Nevertheless, it was apparent thatSouth Asian children with IBD were more likely to consumea westernized diet high in fat and refined sugar and low infresh vegetables compared with their parents and grandpar-ents. The study was not designed to demonstrate a causalrelationship and studies to date aimed at evaluating the re-lationship between diet and IBD have been limited by theinability to define the true composition of each diet. How-ever, among the analyzed dietary components, consumptionof a diet high in fat (29, 30) or refined sugar (31) has beenassociated with an increased risk of IBD, whereas consump-tion of fruit, vegetables, and fiber seem to be associated witha decreased risk (30).

Cigarette use, with its opposing effects on CD and UC (32,33), did not appear to be involved in disease pathogenesis inthe South Asian population of BC. Cigarette smoking waslimited to one individual with IBD, whereas all other patients,parents, and household family members denied any historyof cigarette smoking, preventing the determination of anypossible association.

Studies to date associate both westernization and urban-ization with an increased incidence of IBD and of CD (9,23, 34, 35). Further support for environmental influencesin our study cohort is inferred by the observation that 84%of South Asian IBD patients of BC were second-generationimmigrants. Moreover, most Canadian South Asian familieslived in urban areas, in contrast to their families in the countryof origin.

The study also emphasized the importance of genetic fac-tors, where 79% of the South Asian pediatric IBD populationwas Sikh, with the majority of families originating in the Pun-jab area. Additionally, 35% of patients had a family historyof IBD.

We observed that South Asian patients generally presentedwith a shorter duration of symptoms, suggesting more dra-matic presentations as a result of more extensive colonicinvolvement. While this explanation remains plausible, in-creased awareness of IBD symptoms in the close-knit Sikhcommunity with prompt presentation to a physician might bea contributory factor.

1082 Pinsk et al.

In keeping with previous pediatric studies demonstrating amale preponderance in CD (18, 36), this study demonstrated amale predominance in South Asian CD patients. However, incontrast to an equal sex ratio observed in pediatric UC patients(36), this study also demonstrated a male preponderance forUC. Similarly, Bangladeshi IBD patients from East Londondemonstrated a male predominance in both diseases (23).

In summary, the present study demonstrated both a veryhigh incidence and an increasing incidence of IBD in theSouth Asian pediatric population of BC. South Asian IBDpatients were more likely to have CD and were more likely tobe male and second-generation immigrants. Moreover, SouthAsian patients generally presented with a shorter duration ofsymptoms and had more extensive colonic disease. While ge-netic factors are important, local environmental factors likelyinfluenced presentation and expression of disease. Furtherepidemiological studies are required in such cohorts of pa-tients with high expression of disease to better understand theetiology of IBD.

ACKNOWLEDGMENTS

Dr. Jacobson is a Clinician Scientist supported by the Chil-dren with Intestinal and Liver Disorders (CHILD) and BritishColumbia Children’s Hospital Foundations. The authors wishto thank Ruth Milner for her statistical support.

STUDY HIGHLIGHTS

What Is Current Knowledge

� High incidence rates of ulcerative colitis (UC) observedamong South Asian adult immigrants.

� Second-generation South Asians immigrants are athigher risk for UC.

� While UC has been the predominant disease subtypedescribed in India, Crohn’s disease (CD) is being re-ported.

What Is New Here

� High incidence rate of IBD observed in South Asianchildren of British Columbia (BC) with CD the pre-dominant disease subtype.

� IBD was more common in South Asian males.� South Asian IBD patients had more extensive colonic

disease, especially CD patients.� The number of South Asian patients diagnosed with

IBD in BC over the last decade has increased.

Reprint requests and correspondence: Dr. Kevan Jacobson, Divi-sion of Gastroenterology, B.C. Children’s Hospital, 4480 Oak Street,Room K4-181, Vancouver, BC, Canada, V6H 3V4.

Received August 23, 2006; accepted November 27, 2006.

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CONFLICT OF INTEREST

Guarantor of the article: Kevan Jacobson, M.D.Specific author contributions: All investigators contributedto some degree to the design, data collection and interpreta-tion, and to the writing of the paper. All authors have readand approved the paper.Financial support: NonePotential competing interests: None