Lawrence W. Svenson

The Epidemiology of Inflammatory Bowel Disease in Canada: A Population-Based Study

BACKGROUND:Previously, we have demonstrated a high incidence and prevalence of Crohns 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.

Association of socio-economic status with diabetes prevalence and utilization of diabetes care services

BackgroundLow income appears to be associated with a higher prevalence of diabetes and diabetes related complications, however, little is known about how income influences access to diabetes care. The objective of the present study was to determine whether income is associated with referral to a diabetes centre within a universal health care system.MethodsData on referral for diabetes care, diabetes prevalence and median household income were obtained from a regional Diabetes Education Centre (DEC) database, the Canadian National Diabetes Surveillance System (NDSS) and the 2001 Canadian Census respectively. Diabetes rate per capita, referral rate per capita and proportion with diabetes referred was determined for census dissemination areas. We used Chi square analyses to determine if diabetes prevalence or population rates of referral differed across income quintiles, and Poisson regression to model diabetes rate and referral rate in relation to income while controlling for education and age.ResultsThere was a significant gradient in both diabetes prevalence (χ2 = 743.72, p < 0.0005) and population rates of referral (χ2 = 168.435, p < 0.0005) across income quintiles, with the lowest income quintiles having the highest rates of diabetes and referral to the DEC. Referral rate among those with diabetes, however, was uniform across income quintiles. Controlling for age and education, Poisson regression models confirmed a significant socio-economic gradient in diabetes prevalence and population rates of referral.ConclusionLow income is associated with a higher prevalence of diabetes and a higher population rate of referral to this regional DEC. After accounting for diabetes prevalence, however, the equal proportions referred to the DEC across income groups suggest that there is no access bias based on income.

Prevalence of Cerebral Palsy in Alberta

BACKGROUNDnIn spite of scattered reports to the contrary, concern is continually expressed that the frequency of cerebral palsy has not decreased with modern perinatal/neonatal care. Overall, epidemiological information on cerebral palsy is scant. The generally accepted prevalence is 2 to 2.5 per thousand school-age children.nnnMETHODSnA population-based record linkage study of a presently living cohort of 96,359 children born from April, 1985 through March, 1988 and followed over an eight-year tracking period captured the diagnostic codes for all fee-for-service physician claims, all hospital separations and individual birth data from the Department of Vital Statistics of the Government of Alberta. The ICD-9 code 343 was used to identify subjects. The childhood prevalence and frequency by birthweight-specific sub-groups of cerebral palsy after age three years (congenital, 229 [92.3%]; probable acquired 19 [7.7%]) were identified giving an overall prevalence of 2.57 per 1000. Seventy percent were diagnosed before their third birthday. Cohort prevalence of cerebral palsy for low birthweight children (< 2500 grams) was 17.7, very low birthweight (< 1500 grams), 78.5; and extremely low birthweight (< 1000 grams), 98.4. Low birthweight children made up just over one-third of cases in this study.nnnCONCLUSIONSnCerebral palsy continues to affect a significant number of children suggesting the prevalence of cerebral palsy has not decreased. The proportion of affected children with low birthweight in this study is less than that reported in the literature.

Zones of prevention: the geography of fall injuries in the elderly

Our investigation of the geography of fall injuries considers the relationship between injury prevention and contextual approaches to health research. We use a geographic information system (GIS) to describe the pattern of emergency department reported falls of the elderly in the Capital Health Region, an administrative health area in Alberta, Canada. We used empirical Bayes estimates to obtain a geographic measure of fall incidence over the study area and a cluster detection statistic to measure the presence of a significant spatial cluster in the region. Inner-city Edmonton had the highest incidence of risk, suburban Edmonton the lowest, and surrounding rural regions and smaller communities had more moderate fall incidence. We argue that descriptive geography can enhance the effectiveness of injury prevention programs by identifying zones of high risk, even when the individual-level and contextual factors that explain the underlying patterns are unknown.

Regional Variations in the Prevalence Rates of Multiple Sclerosis in the Province of Alberta, Canada

Multiple sclerosis (MS) prevalence rates were examined for the fiscal years 1984/1985-1988/1989, in the province of Alberta, Canada, by age, sex and census division. Data were derived from the health care records of individuals registered with the Alberta Health Care Insurance Plan which requires registration by all residents of the province (approximately 2.4 million). The overall crude prevalence rate was 216.7 per 100,000 (173.1 for males; 260.3 for females) population. Females had a significantly higher prevalence (p < 0.05) and the rates were highly correlated between the sexes (r = 0.94, p < 0.01). The present study confirms other studies finding a high prevalence rate within the province of Alberta. The prevalence rate for Alberta is among the highest reported in the world indicating that the province appears to be an excess risk area relative to other global locations. Also, the results indicate that MS is unevenly distributed throughout the province which offers support for the involvement of environmental factors related to the onset of this disorder.

Population-based study of medically treated self-inflicted injuries

OBJECTIVEnSelf-inflicted injury is commonly seen in emergency departments (EDs). It may be a pre-cursor to death by suicide. The objective of this study was to examine the epidemiology of self-inflicted injury presentations to EDs in the province of Alberta.nnnMETHODSnSelf-inflicted injury records for the 3 fiscal years 1998/99 to 2000/01 were accessed from the Ambulatory Care Classification System, a database that captures all ED encounters in the province of Alberta. Available data for each case included demographic details, location and time of visit, diagnoses and procedures.nnnRESULTSnThere were 22 396 self-inflicted injury presentations to Alberta EDs during the study period. Self-inflicted injury rates were higher in females, younger patients, those on social services and those with Aboriginal treaty status. There were higher rates of return visits in the year following the self-inflicted injury than in other patient groups. Data showed regional variation. Trends could be seen in the timing of self-inflicted injury presentations by hour of day, day of week, and month of year.nnnCONCLUSIONSnSelf-inflicted injury is common, with particularly high rates demonstrated among marginalized populations. This study provides comprehensive data on those who present with self-inflicted injuries, and can be used to guide further treatment, research and evaluation for this population.

Incident Cerebrovascular Disease in Rural and Urban Alberta

Study Objective: This study examines the pattern of incidence and health service utilisation of cerebrovascular disease cases in urban and rural areas within a publicly funded health care system. Design: A population-based study covering a large geographic region, using population-wide administrative health data. Age- and sex-standardised incidence and mortality rates were calculated for rural and urban areas. Final status (discharge or death), place of service and place of residence were reported for all cases across several different subsets of cerebrovascular disease. Setting: The province of Alberta, located in western Canada. Participants: Incident cases of cerebrovascular disease (stroke and transient ischaemic attack) and 4 different definitions of incident stroke were identified from data on emergency department admissions in the 1999/2000 fiscal year. Main Results: The rate of cerebrovascular disease per 10,000 was similar between urban (13.24) and rural (13.82) areas. Rural residents frequently reported their incident episode to urban emergency departments. Although the mortality is similar between urban and rural residents, rural dwellers die more frequently in the emergency department setting than urban dwellers, who die more often as in-patients. Conclusions: Overall mortality is similar between urban and rural residents. A large proportion of rural residents receive diagnoses and treatment for cerebrovascular disease in urban areas. Location of service and location of death differs between rural and urban cases of cerebrovascular disease.

Clinical and medication profiles stratified by household income in patients referred for diabetes care.

BackgroundLow income individuals with diabetes are at particularly high risk for poor health outcomes. While specialized diabetes care may help reduce this risk, it is not currently known whether there are significant clinical differences across income groups at the time of referral. The objective of this study is to determine if the clinical profiles and medication use of patients referred for diabetes care differ across income quintiles.MethodsThis cross-sectional study was conducted using a Canadian, urban, Diabetes Education Centre (DEC) database. Clinical information on the 4687 patients referred to the DEC from May 2000 – January 2002 was examined. These data were merged with 2001 Canadian census data on income. Potential differences in continuous clinical parameters across income quintiles were examined using regression models. Differences in medication use were examined using Chi square analyses.ResultsMultivariate regression analysis indicated that income was negatively associated with BMI (p < 0.0005) and age (p = 0.023) at time of referral. The highest income quintiles were found to have lower serum triglycerides (p = 0.011) and higher HDL-c (p = 0.008) at time of referral. No significant differences were found in HBA1C, LDL-c or duration of diabetes. The Chi square analysis of medication use revealed that despite no significant differences in HBA1C, the lowest income quintiles used more metformin (p = 0.001) and sulfonylureas (p < 0.0005) than the wealthy. Use of other therapies were similar across income groups, including lipid lowering medications. High income patients were more likely to be treated with diet alone (p < 0.0005).ConclusionOur findings demonstrate that low income patients present to diabetes clinic older, heavier and with a more atherogenic lipid profile than do high income patients. Overall medication use was higher among the lower income group suggesting that differences in clinical profiles are not the result of under-treatment, thus invoking lifestyle factors as potential contributors to these findings.

Parental ancestry and risk of multiple sclerosis in Alberta, Canada.

Self-reported population ancestry data for the 19 census divisions (CDs) of Alberta, Canada, were correlated with multiple sclerosis (MS) prevalence rates in those divisions, for men and women separately; and parental ancestry was compared between a group of MS patients and controls attending the University of Alberta MS Clinic. At the CD level, there was a positive correlation between single Scandinavian ancestry and MS prevalence in men, but this was not confirmed in the case-control comparison. The case-control comparison indicated an excess risk of MS associated with single non-specific European as opposed to British ancestry in men only. When paternal versus maternal ancestry was considered separately, there was an excess risk of MS associated with non-specific European as opposed to British ancestry for both men and women, but on the fathers side only. Aboriginal ancestry was negatively associated with MS prevalence at the CD level in both men and women; and no MS patients with aboriginal origin were among cases assembled through the MS clinic.

Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE): epidemiology, emerging organisms, and economics

BackgroundEach year in Canada there are 5 million episodes of acute gastroenteritis (AGE) with up to 70xa0% attributed to an unidentified pathogen. Moreover, 90xa0% of individuals with AGE do not seek care when ill, thus, burden of disease estimates are limited by under-diagnosing and under-reporting. Further, little is known about the pathogens causing AGE as the majority of episodes are attributed to an “unidentified” etiology. Our team has two main objectives: 1) to improve health through enhanced enteric pathogen identification; 2) to develop economic models incorporating pathogen burden and societal preferences to inform enteric vaccine decision making.Methods/DesignThis project involves multiple stages: 1) Molecular microbiology experts will participate in a modified Delphi process designed to define criteria to aid in interpreting positive molecular enteric pathogen test results. 2) Clinical data and specimens will be collected from children aged 0–18xa0years, with vomiting and/or diarrhea who seek medical care in emergency departments, primary care clinics and from those who contact a provincial medical advice line but who do not seek care. Samples to be collected will include stool, rectal swabs (Nu2009=u20092), and an oral swab. Specimens will be tested employing 1) stool culture; 2) in-house multiplex (Nu2009=u20095) viral polymerase chain reaction (PCR) panel; and 3) multi-target (Nu2009=u200915) PCR commercially available array. All participants will have follow-up data collected 14xa0days later to enable calculation of a Modified Vesikari Scale score and a Burden of Disease Index. Specimens will also be collected from asymptomatic children during their well child vaccination visits to a provincial public health clinic. Following the completion of the initial phases, discrete choice experiments will be conducted to enable a better understanding of societal preferences for diagnostic testing and vaccine policy. All of the results obtained will be integrated into economic models.DiscussionThis study is collecting novel samples (e.g., oral swabs) from previously untested groups of children (e.g., those not seeking medical care) which are then undergoing extensive molecular testing to shed a new perspective on the epidemiology of AGE. The knowledge gained will provide the broadest understanding of the epidemiology of vomiting and diarrhea of children to date.