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Cvd mort

  1. 1. CCORT ATLAS PAPER Regional variations in cardiovascular mortality in Canada Woganee A Filate MHSc1,2, Helen L Johansen PhD3, Courtney C Kennedy MSc2, Jack V Tu MD PhD2,4,5 for the Canadian Cardiovascular Outcomes Research Team WA Filate, HL Johansen, CC Kennedy, JV Tu. Regional Mortalité d’origine cardiovasculaire : varia- variations in cardiovascular mortality in Canada. Can J Cardiol tions régionales au Canada 2003;19(11):1241-1248. BACKGROUND: Cardiovascular disease (CVD) is the leading CONTEXTE : Les maladies cardiovasculaires (MCV) constituent la cause of death in Canada with wide, unexplained regional variations principale cause de décès au Canada, et la mortalité qui y est liée connaît in heart disease mortality. However, no studies to date have explored d’importantes variations régionales inexpliquées. Cependant, aucune the relationship between a number of health region characteristics étude n’a porté sur le lien entre certaines caractéristiques des régions san- and regional variation in heart disease mortality rates across Canada. itaires et les variations régionales enregistrées de taux de mortalité d’orig- INTRODUCTION: We studied the contribution of various tradi- ine cardiaque au Canada. tional cardiac risk factors, social determinants of health and other INTRODUCTION : Nous avons étudié le poids de différents facteurs de community characteristics to regional variations in heart disease risque classiques de MCV, de déterminants sociaux de la santé et d’autres mortality rates across Canada. caractéristiques des collectivités dans les variations régionales de taux de mortalité d’origine cardiaque au Canada. METHODS: Cardiovascular disease and ischemic heart disease MÉTHODE : Nous avons obtenu de Statistique Canada les taux de mor- (IHD) age-standardized mortality rates were obtained from Statistics talité par MCV et cardiopathie (CP), normalisés selon l’âge pour les Canada for three years – 1995 to 1997. Health region characteristics années 1995 à 1997. Quant aux caractéristiques régionales, elles ont été were taken from the 2000/2001 Canadian Community Health tirées de l’Enquête sur la santé dans les collectivités canadiennes 2000- Survey, and the 1996 Canadian Census and the Labour Force Survey. 2001, du recensement de 1996 et de l’Enquête sur la population active. Linear regression analyses and analyses of variance were employed to Des liens entre les caractéristiques des régions sanitaires et les taux de identify relationships between these health region characteristics and mortalité par MCV et CP ont été établis à partir d’analyses de régression CVD and IHD mortality rates. linéaire et d’analyses de la variance. RESULTS: Significant regional variations in CVD mortality rates RÉSULTATS : D’importantes différences régionales ont été relevées per 100,000 population were observed. Newfoundland and Labrador quant aux taux de mortalité liés aux MCV par tranche de 100 000 habi- had the highest CVD and IHD mortality rates, while Nunavut and tants. Terre-Neuve et le Labrador ont enregistré les taux de mortalité par the Northwest Territories had the lowest CVD and IHD mortality MCV et CP les plus élevés, tandis que le Nunavut et les Territoires du rates. Health region smoking and unemployment rates were identi- Nord-Ouest ont enregistré les taux les plus faibles. Les taux régionaux de fied as the most important factors associated with CVD and IHD tabagisme et de chômage se sont révélés les principaux facteurs associés à mortality at the health region level. la mortalité par MCV et CP au niveau des régions sanitaires. CONCLUSIONS: Significant regional variations in age-standard- CONCLUSIONS : D’importantes différences régionales ont été relevées ized CVD and IHD mortality were noted both at the provincial/terri- quant aux taux de mortalité par MCV et CP, normalisés selon l’âge, tant torial level and the health region level. Efforts to reduce CVD and au niveau provincial ou territorial qu’au niveau régional. Les efforts visant IHD mortality in Canada require attention to both traditional risk à réduire la mortalité par MCV et CP au Canada devraient cibler à la fois factors (eg, smoking) and broader determinants of health (eg, unem- les facteurs de risque classiques de MCV (tabagisme) et des déterminants plus larges de la santé (taux de chômage). ployment rates). Key Words: Cardiovascular disease mortality; Determinants of health; Ischemic heart disease mortality; Regional variation; Regression ardiovascular disease (CVD) is the leading cause of mortal- standardized mortality rates for CVD and IHD by province andC ity in Canada, accounting for the deaths of 78,942Canadians in 1999 (1). However, there is wide, unexplained health region averaged over three years (1995 to 1997). We then analyze the relationship between various health regionvariation in the rates of death from CVD in different health characteristics and age-standardized CVD and IHD mortalityregions of Canada. The first objective of this paper is to describe rates, using data taken from the Canadian Community Healthregional variations in mortality rates for CVD and ischemic Survey (CCHS) (2) and from the 1996 Canadian Census (3)heart disease (IHD) in Canada. Specifically, we present age- and the Labour Force Survey (4) from Statistics Canada. An1Department of Public Health Sciences, University of Toronto, Toronto, Ontario; 2Institute for Clinical Evaluative Sciences, Toronto, Ontario; 3Health Division, Statistics Canada, Ottawa, Ontario; 4Division of General Internal Medicine, Sunnybrook and Women’s College Health Sciences Centre, Toronto, Ontario; 5Department of Health Policy, Management and Evaluation, University of Toronto, Toronto, OntarioCorrespondence and reprints: Dr Jack V Tu, Institute for Clinical Evaluative Sciences, G106-2075 Bayview Avenue, Toronto, Ontario M4N 3M5. Telephone 416-480-6083, fax 416-480-6048, e-mail tu@ices.on.caReceived for publication July 30, 2003. Accepted August 14, 2003Can J Cardiol Vol 19 No 11 October 2003 ©2003 Pulsus Group Inc. All rights reserved 1241
  2. 2. Filate et alunderstanding of the factors that may explain regional varia- could not be attributed to a particular province or age or sextions in mortality rates is necessary before interventions can be group were excluded from the analysis to not bias the results.undertaken to reduce the death rate from cardiac disease. Rates were age standardized using the direct method and the Previous studies have demonstrated geographic variations 1991 Canadian Census population structure. Rates were basedin heart disease mortality in the United States (2), within on averaged mortality data for three years – 1995 to 1997 – toCanada (6,7) and in Ontario (8). However, no studies have enable more stable estimates at the health region level. Thisexamined the association between various health region char- average was subsequently divided by the population estimate ofacteristics and geographic variations for heart disease mortali- the middle year, 1996.ty across Canada. Studies have shown that CVD mortality To examine the relationship between health region factorsvaries in the United States according to levels of urbanization and heart disease mortality, we grouped health region-level(9). Moreover, a study conducted by Sundquist and colleagues characteristics collected in the CCHS and the 1996 Census(10) demonstrated that neighbourhood environment factors, and the Labour Force Survey into three categories: traditionalincluding unemployment status and sociodemographic factors, cardiac risk factors (prevalence of daily smoking, obesity, highhave an intermediate influence on CVD risk factors and blood pressure and physical inactivity); social determinants oflifestyle factors. In this study, we aimed to determine the rela- health (proportion of the population with postsecondary edu-tionship between health region characteristics and CVD and cation, unemployed, with low income rate, with incomeIHD mortality rates in Canada. inequality and with high life stress); and other community We hypothesized that variations in the prevalence of tradi- characteristics (population density, immigrant population,tional cardiac risk factors, such as smoking and obesity, likely minority population and urban population). To elucidate thecontribute to regional variations in death rates. However, we unique contribution of each community characteristic per cat-also suspected that nonmedical social determinants of health, egory to CVD and IHD mortality, two sets of three multivari-including socioeconomic status and urbanism, may play an ate linear regression models were created. To keep the analysesimportant role in regional differences in mortality from heart simple, logistical regressions were not carried out. Definitionsdisease. As such, this paper compares the relative impact of of the health region characteristics from the CCHS, theboth the medical and broader determinants of cardiovascular Canadian Census and the Labour Force Survey that werehealth on heart disease mortality. examined can be found in Appendix I of this paper. To further explore the relationship between CVD and IHD METHODS mortality rates and traditional cardiac risk factors, social deter-Data sources minants of health and other community characteristics, analy-Age-standardized mortality rates, calculated using death ses of variance were conducted. In these analyses, healthcounts and population size estimates by province, were regions were categorized according to the distribution of theirobtained from Statistics Canada (11). Causes of death cate- CVD and IHD mortality in five mortality rate ratio groups rel-gories were defined as CVD diagnoses (International ative to the national average (minimum to less than 0.75,Classification of Diseases, 9th Revision [ICD-9] codes 390 to 0.75 to less than 0.90, 0.90 to less than 1.10, 1.10 to less than459) and IHD (ICD-9 codes 410 to 414). IHD deaths refer 1.30, 1.30 to maximum). Within each rate ratio category, thestrictly to those deaths due to IHD (ie, acute myocardial prevalence of each community characteristic among healthinfarction and angina), whereas CVD deaths include IHD regions was averaged. Analyses of variance were conducted todeaths but also deaths due to arrhythmias, congestive heart determine whether the differences in the average prevalence offailure, stroke and other cardiac disorders. Cardiac risk factors the characteristics between mortality rate ratio categories wereand some measures of social determinants of health, by health beyond what would be expected by chance alone.region, were obtained from the first round of the CCHS fromStatistics Canada in 2000/2001 (11). The key objective of the Interpretative cautionsCCHS is to provide estimates of health determinants, health Readers should use caution when interpreting regional differ-status and health system utilization patterns of Canadians by ences in mortality rates. It is likely that some differences mayhealth region. Data from the CCHS covered approximately be the result of chance alone, particularly when a large number98% of the Canadian population aged 12 years or older (12). of comparisons are being made (8). Furthermore, otherThe total sample size of the first cycle of the CCHS was researchers and studies have expressed apprehension about the131,535 household respondents, representing a response rate of quality of cause-of-death information recorded on death cer-84.7% (13). As a population-based survey, the CCHS is subject tificates, particularly with regards to IHD (8). While there isto biases. The survey relies on self-report or proxy-report and uncertainty about the accuracy of the cause of death recordedthe voluntary participation of randomly selected participants, on death certificates in Canada, it is unlikely that differencesand as such, the results were not independently verified (12). in death certificate coding explain all of the regional differ-Data were obtained from the 2000/2001 CCHS because earlier ences in cardiovascular mortality in Canada.estimates by health region were not available. Data on othercommunity characteristics and measures of socioeconomic sta- RESULTStus were obtained from the 1996 Canadian Census (3) and the Age-standardized CVD and IHD mortality rates per 100,000Labour Force Survey (4) from Statistics Canada. population by province from 1995 to 1997 are shown in Table 1. The overall Canadian age-standardized CVD andStatistical analyses IHD mortality rates were 245.8 and 136.4/100,000 popula-Mortality data for this study were provided by Statistics tion, respectively. Provincial CVD mortality rates rangedCanada. Rates were calculated for each province, territory and from a high of 320.6/100,000 population in Newfoundlandhealth region for adults 20 years of age and older. Deaths that and Labrador to a low of 196.9/100,000 population in the1242 Can J Cardiol Vol 19 No 11 October 2003
  3. 3. Cardiovascular mortalityTABLE 1 Figure 1 is a map of age-standardized CVD mortality ratesAge-standardized cardiovascular and ischemic heart by health region in Canada from 1995 to 1997. Less denselydisease mortality rates per 100,000 population in Canada,1995 to 1997, classified by province/territory and sex populated regions had higher rates of CVD mortality than more densely populated regions in Canada, with the excep-CARDIOVASCULAR DISEASE tion of some northern communities, as shown in this map. Mortality rate per 100,000 populationProvince or territory Men Women Overall The health region with the highest CVD mortality rate was Région de Nunavik in Quebec, with a mortality rate ofCanada 316.7 192.7 245.8 430.8/100,000 population. Other health regions with higherNewfoundland and Labrador 406.1 252.2 320.6 than average CVD mortality rates included the GrenfellPrince Edward Island 356.8 198.2 267.1 Regional Health Services Board, and the Health andNova Scotia 345.6 197.5 259.5 Community Services Eastern Region of Newfoundland andNew Brunswick 334.3 199.1 257.7 Labrador, as well as the Northern Lights Health Authority inQuebec 325.8 192.5 247.6 Alberta, with death rates of 363.2, 362.4 and 354.9/100,000Ontario 314.4 194.5 245.7 population, respectively. The health region with the lowestManitoba 331.9 204.6 259.6 CVD mortality rate was the Northwestern Regional HealthSaskatchewan 308.4 180.1 237.9 Authority in Alberta, with a rate of 167.0/100,000 popula-Alberta 311.2 199.3 249.0 tion. The health region of Richmond, British Columbia alsoBritish Columbia 285.8 174.3 223.1 had a low CVD mortality rate compared with the rest of Canada, with a rate of 192.5/100,000 population.Yukon 350.4 231.2 288.7 Figure 2 is a map of age-standardized IHD mortality rates byNorthwest Territories 240.9 146.8 196.9 health region in Canada from 1995 to 1997. As was the caseNunavut 241.9 189.5 215.6 with CVD mortality, IHD mortality was higher in regions thatISCHEMIC HEART DISEASE were less densely populated than in regions that were more Mortality rate per 100,000 population densely populated, with the exception of a few northern com-Province or territory Men Women Overall munities. The health regions with the highest IHD mortalityCanada 188.2 97.3 136.4 rates compared with the Canadian average included Kent-Newfoundland and Labrador 238.1 127.8 176.6 Chatham Public Health Unit in Ontario, Northern LightsPrince Edward Island 203.3 102.2 147.8 Regional Health Authority in Alberta, and the Health andNova Scotia 204.5 92.6 139.4 Community Services Eastern Region of Newfoundland and Labrador at 234.1, 227.8 and 206.6/100,000 population,New Brunswick 176.0 93.9 129.6 respectively. The health region with the lowest IHD mortalityQuebec 199.5 102.3 142.9 rate was Nunavut, with a rate of 40.2/100,000 population.Ontario 194.1 102.8 141.8 Other health regions with low IHD mortality rates includedManitoba 194.5 101.8 142.4 the Northwest Territories, Prince Albert Service Area inSaskatchewan 173.4 81.6 123.0 Saskatchewan and Capital Health Region in BritishAlberta 173.7 91.6 127.9 Columbia, with mortality rates of 85.0, 96.9 and 97.4/100,000British Columbia 158.1 77.8 113.0 population, respectively. Supplementary data tables showingYukon 154.6 85.3 119.2 the age-standardized CVD and IHD mortality rates for eachNorthwest Territories 105.0 62.8 85.0 health region in Canada are available on the CanadianNunavut 56.0 * 40.2 Cardiovascular Outcomes Research Team (CCORT)’s Web site (*Data suppressed due to very small underlying counts and extremely highvariability. Standardized to 1991 population. Data taken from reference 11 Table 2 summarizes the results of the regression analyses of various health region characteristics with CVD and IHD mor- tality. The prevalence of daily smokers in health regions was very significantly related to both CVD and IHD mortalityNorthwest Territories. Most provinces had a CVD mortality (P<0.01). The prevalence of obese individuals in healthrate higher than the national average except for regions was significantly related to CVD mortality but not toSaskatchewan, British Columbia, Ontario, the Northwest IHD mortality (P<0.01 versus P=0.62). Among social deter-Territories and Nunavut. Across all provinces, men had a minants of health, the prevalence of individuals with postsec-higher CVD mortality rate than women. The overall ondary education was inversely associated with both CVDCanadian CVD mortality rate for men was 316.7/100,000 pop- and IHD mortality (P<0.01 and P=0.03, respectively), whileulation, while for women, it was 192.7/100,000 population. the unemployment rate in a community was positively associ- Provincial IHD mortality rates ranged from a high of ated with CVD and IHD mortality (P=0.02 and P<0.01,176.6/100,000 population in Newfoundland and Labrador to a respectively). Finally, the low income rate was negativelylow of 40.2/100,000 population in Nunavut. Several provinces related to IHD mortality but not to CVD mortality (P=0.01had an IHD mortality rate that was higher than the Canadian versus P=0.58).average, including Newfoundland and Labrador, Prince Analyses of community characteristics indicate that theEdward Island, Nova Scotia, Quebec, Ontario and Manitoba. proportion of immigrants was negatively associated with CVDAcross all provinces, as with CVD mortality, men had a higher mortality but not to IHD mortality (P=0.04 versus P=0.89),IHD mortality rate than women. The overall Canadian IHD while the greater the number of people belonging to a visiblemortality rate for men was 188.8/100,000 population and for minority group living in a community, the less likely the com-women was 97.3/100,000 population. munity had high IHD mortality (P=0.04).Can J Cardiol Vol 19 No 11 October 2003 1243
  4. 4. Filate et alFigure 1) Age-standardized cardiovascular disease (CVD) mortality rates per 100,000 population by health region (HR), 1995 to 1997. Data fromStatistics Canada, 2001 (11). PEI Prince Edward IslandFigure 2) Age-standardized ischemic heart disease (IHD) mortality rates per 100,000 population by health region (HR), 1995 to 1997. Data fromStatistics Canada, 2001 (11). PEI Prince Edward Island1244 Can J Cardiol Vol 19 No 11 October 2003
  5. 5. Cardiovascular mortality Table 3 displays the average prevalence of various commu- TABLE 2nity characteristics of health regions according to the distribu- Regression analyses of traditional cardiac risk factors, social determinants of health and other communitytion of their CVD mortality rate ratios. According to Table 3, characteristics for age-standardized cardiovascularall community characteristics were statistically significant disease (CVD) and ischemic heart disease (IHD) mortalityexcept for the prevalence of low income rate, income inequal- in Canada, 1996, in 120 health regions*ity and urban population. These results reconfirm the impor- Regression coefficientstance of traditional cardiac risk factors in CVD mortality, and Community factor CVD mortality P IHD mortality Pstrengthen the importance of certain social determinants of Model 1 – Traditional cardiac risk factorshealth and other community characteristics, such as popula- Daily smoking 3.12847 <0.01 2.39444 <0.01tion density and population structure, on CVD mortality. In Obese body mass index 2.87836 <0.01 0.31664 0.62general, health regions in Canada with high CVD mortality (international standard)have a significantly (P<0.05) higher prevalence of cardiac risk Diabetes –0.21149 0.95 0.94723 0.73factors, lower socioeconomic status, lower population density, Hypertension –0.81393 0.58 1.78687 0.15and lower immigrant and minority populations than health Physical inactivity –0.04151 0.91 –0.38807 0.24regions with low CVD mortality rates. Forty-two per cent ofthe regional variation in CVD mortality in Canada can be Model 2 – Social determinants of healthexplained by the variation in the prevalence of traditional car- Postsecondary education –1.56325 <0.01 –0.87730 0.03diac risk factors, 21% by social determinants of health and Unemployment rate, 1996 2.16340 0.02 2.72763 <0.0120% by other community characteristics in isolation. When all Low income rate, 1995 –0.60241 0.58 –2.14807 0.01of the factors are analyzed simultaneously, traditional cardiac Income inequality –0.00710 0.99 –2.24548 0.35risk factors, social determinants of health and other communi- High life stress –1.40798 0.08 0.49583 0.42ty characteristics explain 49% of the variation in CVD mortal-ity in Canada, compared with 45% of the variation explained Model 3 – Other community characteristicsby traditional cardiac risk factors and social determinants of Population density 0.00225 0.75 0.00546 0.33health only, and 42% by traditional cardiac risk factors alone. Immigrant population –1.67424 0.04 0.09010 0.89 Table 4 displays the average prevalence of various commu- Minority population –0.37264 0.71 –1.61455 0.04nity characteristics of health regions according to the distribu-tion of their IHD mortality rate ratios. According to this table, Urban population 0.23684 0.19 0.14943 0.29only selected traditional cardiac risk factors and other commu- *See Appendix II for a list of health regions with missing or suppressed datanity characteristics, including education, were statistically sig- and definitions of each community factor. Data taken from Health Indicators, Statistics Canada (11)nificant. Health regions with high IHD mortality had astatistically significant higher prevalence of daily smoking, obe-sity and high blood pressure, and a lower prevalence of postsec-ondary education, and immigrant and minority populations incomparison with health regions with lower IHD mortality.Twenty-five per cent of the regional variation in IHD mortalityTABLE 3Average prevalence of community characteristics of health regions according to CVD mortality rate ratio categories CVD mortality rate ratios* Minimum to <0.75 0.75 to <0.90 0.90 to <1.10 1.10 to <1.30 1.30 to maximum P for (n=1) (n=17) (n=72) (n=38) (n=9) trendTraditional cardiac risk factorsDaily smoking (%) N/A 18.09 21.98 25.52 25.17 <0.01Obese body mass index (%) N/A 14.34 16.81 19.78 22.65 <0.01Diabetes (%) N/A 4.21 4.26 4.84 5.28 <0.01High blood pressure (%) N/A 12.34 12.89 14.29 13.68 0.02Physical inactivity (%) N/A 47.96 46.27 49.35 49.13 0.20Social determinants of healthPostsecondary education (%) N/A 52.91 49.04 47.07 46.08 0.01Unemployment rate, 1996 (%) N/A 7.86 8.96 11.51 15.72 <0.01Low income rate, 1995 (%) N/A 15.23 13.87 14.21 17.15 0.28Income inequality (%) N/A 22.31 22.89 22.76 23.00 0.48High life stress (%) N/A 23.81 24.81 23.60 17.03 <0.01Other community characteristicsPopulation density (population/km2) N/A 754.45 179.15 33.26 9.60 <0.01Immigrant population (%) N/A 22.01 10.80 6.87 4.27 <0.01Minority population (%) N/A 15.82 5.10 1.69 2.17 <0.01Urban population (%) N/A 74.71 64.72 59.21 58.20 0.13*Rate ratios for each region were obtained by dividing the health region cardiovascular disease (CVD) mortality rate by the Canadian CVD mortality rate.The prevalenceof each characteristic was averaged among health regions in the rate ratio categories. Data taken from Health Indicators, Statistics Canada. N/A Not availableCan J Cardiol Vol 19 No 11 October 2003 1245
  6. 6. Filate et alTABLE 4Average prevalence of community characteristics of health regions according to IHD mortality rate ratio categories IHD mortality rate ratios* Minimum to <0.75 0.75 to <0.90 0.90 to <1.10 1.10 to <1.30 1.30 to maximum P for (n=7) (n=29) (n=53) (n=35) (n=12) trendTraditional cardiac risk factorsDaily smoking (%) 18.66 19.96 22.58 25.30 24.89 <0.01Obese body mass index (%) 14.26 16.40 17.43 18.67 19.80 0.043Diabetes (%) 4.04 4.34 4.28 4.73 4.96 0.13High blood pressure (%) 12.20 12.49 12.76 14.64 13.69 <0.01Physical inactivity (%) 46.24 47.30 46.97 48.85 46.69 0.80Social determinants of healthPostsecondary education (%) 57.04 49.34 48.95 47.10 49.24 0.01Unemployment rate, 1996 (%) 7.84 8.75 9.55 11.05 11.59 0.12Low income rate, 1995 (%) 13.68 14.75 14.52 13.73 13.86 0.89Income inequality (%) 21.78 22.91 22.78 22.84 22.67 0.50High life stress (%) 24.56 23.01 24.63 24.36 22.42 0.30Other community characteristicsPopulation density (population/km2) 116.01 458.34 186.19 44.66 41.48 0.15Immigrant population (%) 18.10 15.79 9.47 7.41 8.59 <0.01Minority population (%) 9.00 10.84 4.30 2.05 2.25 <0.01Urban population (%) 79.90 66.69 63.26 59.99 68.10 0.34*Rate ratios for each region were obtained by dividing the health region ischemic heart disease (IHD) mortality rate by the Canadian IHD mortality rate.The preva-lence of each characteristic was averaged among health regions in the rate ratio categories. Data taken from Health Indicators, Statistics Canada (8)in Canada can be explained by variations in the prevalence of cation campaigns in Canadian communities. We found that atraditional cardiac risk factors, 17% by social determinants of health region’s smoking rate was associated with CVD mortality,health and 12% by other community characteristics. When consistent with the smoking-attributable mortality rates calcu-analyzed simultaneously, 34% of the variation in IHD deaths lated in the CCORT Cardiac Atlas Risk Factor paper (14). Thisin Canada is explained by traditional cardiac risk factors, social suggests that efforts (ie, increased taxes, health promotion activ-determinants of health and other community characteristics; ities) to decrease smoking rates in communities with high car-30% of the variation is explained by traditional cardiac risk diac mortality rates would likely have an important contributionfactors and social determinants of health combined, and 25% in decreasing heart disease mortality in many health regionsby traditional cardiac risk factors alone. across Canada. Our analyses also suggest that greater attention to obesity rates is necessary in many of these health regions giv- DISCUSSION en the well-established link between obesity and increased riskThis study allowed us to quantify the regional variability in of mortality from CVD (17,18). Health promotion programsheart disease mortality in Canada, in addition to identifying aimed at improving dietary intake and decreasing serum choles-characteristics of health regions with higher and lower than terol concentrations could avert many cardiovascular deaths, asexpected CVD and IHD mortality. We found that, in general, they have in other jurisdictions (19,20). Although it may seemhealth regions in Canada with higher levels of heart disease paradoxical that well-recognized cardiac risk factors such as dia-mortality are regions where the prevalence of smoking and betes and hypertension were not significant in many of ourobesity are higher than the national average. Factors associat- analyses, this may reflect the fact that there are less regionaled with lower mortality rates include lower unemployment variations in the prevalence of these factors than there are inrates, a higher proportion of individuals with postsecondary smoking or obesity rates; also, diabetes and hypertension rateseducation, and a greater proportion of immigrants and mem- were based on self-report and likely underestimate the truebers of visible minority groups. Although there are complex prevalence in communities. Nevertheless, their importance ininter-relationships between all of these variables, our analyses individual patients should not be underestimated.may potentially allow health regions with higher mortality and Key to the effectiveness of heart health promotion programs ishigher risk factor levels to develop and target health promo- the recognition that the broader determinants of health are alsotion programs aimed at reducing mortality from heart disease important contributors to the cardiac health status of communi-and promoting overall cardiovascular health. ties across Canada (21). We found that regions with higher Data from this study and the CCORT Cardiac Atlas Risk unemployment rates and lower rates of postgraduate educationFactor paper (14) can potentially be used by health regions to had higher rates of cardiac deaths, suggesting that efforts todevelop health promotion programs aimed at reducing risk fac- improve the employment status and educational attainment oftors for and mortality from CVD. Community-wide health edu- Canadians may indirectly yield significant health benefits,cation programs aimed at reducing CVD and associated risk although this hypothesis remains to be scientifically proven.factors have demonstrated sustained effects in other countries Regions with lower mortality rates also tended to have higher(15,16) and could be used as models for community health edu- proportions of immigrants and visible minority groups, which1246 Can J Cardiol Vol 19 No 11 October 2003
  7. 7. Cardiovascular mortalitymay reflect the preferential selection of healthy immigrants CONCLUSIONSfor immigration into Canada and counteracts the notion of Wide regional variations in cardiovascular mortality rates acrosssome that immigrants place a disproportionate burden on health regions in Canada were observed, which are partiallyCanada’s health care system. Although the mechanisms by explained by differences in prevalence of traditional cardiac riskwhich many of these broader determinants of health influ- factors such as smoking and obesity, but also by broader determi-ence cardiovascular mortality are not completely understood, nants of health, such as the employment status and educationalit is important for policy makers to be aware of the significant attainment of residents in different regions of Canada. Givenrole they play in explaining geographic variation in CVD that CVD is the leading cause of death in Canada, we believemortality so that appropriate policy decisions outside the that additional investments in understanding these determinantshealth sector are made. are vital towards improving the cardiac health status of A limitation of this study is the absence of detailed clinical Canadians and could potentially yield large health benefits toexplanations for all of the apparent variation in CVD and IHD Canadians across the country. Current health promotion effortsmortality rates across Canada. For example, we did not have could likely be most profitably devoted towards reducing the stilldata on blood cholesterol levels or other biochemical factors substantial rates of smoking in many communities across Canada.and genetic factors that would be necessary for a more compre-hensive analysis of this issue. Differences in acute treatment of FUNDING: This project was jointly supported by operatingcardiac patients across health regions (eg, use of thrombolytic grants to CCORT ( from the Canadian Institutestherapy, invasive cardiac procedures, beta-blockers, etc) and for Health Research and the Heart and Stroke Foundation ofout-of-hospital services (eg, ambulance services, cardiac reha- Canada. Dr Tu is supported by a Canada Research Chair in Healthbilitation programs, etc) also likely play an important role in Services Research.explaining geographic variations. Some of these factors will beexplored in other papers of the Atlas project. Additionally, ACKNOWLEDGEMENTS: The authors sincerely thanksome health region characteristics were measured in more Yanyan Gong for her statistical assistance. The authors would alsorecent years (2000/2001) compared with mortality rates like to acknowledge CCORT Research Coordinator Susan Brien(1995 to 1997), which may have introduced some bias into for her work in the final production of this manuscript, and graph-the analyses. However, previous studies have shown that CVD ic designer Brian Graves for producing and designing the mapsand IHD mortality rates are relatively stable over time at the featured in the region level (8).APPENDIX IIndividual and communitycharacteristics Definition ReferenceTRADITIONAL CARDIAC RISK FACTORSDaily smokers Proportion of the population aged 12 years and older who reported being Statistics Canada, Canadian Community either a daily smoker or occasional smoker Health Survey, 2000/2001, health file (2)Obesity Proportion of the population aged 20 to 64 years excluding pregnant women Statistics Canada, Canadian Community and persons shorter than 0.914 m (3 feet) tall or taller than 2.108 m (6 feet Health Survey, 2000/2001, health file (2) 11 inches) whose body mass index was 30 kg/m2 or greater (international standard)Diabetes Proportion of the population aged 12 years and older who reported that they Statistics Canada, Canadian Community had been diagnosed by a health professional as having diabetes Health Survey, 2000/2001, health file (2)Hypertension Proportion of the population aged 12 years and older who reported that they Statistics Canada, Canadian Community had been diagnosed by a health professional as having high blood pressure Health Survey, 2000/2001, health file (2)Physical inactivity Proportion of the population aged 12 years and older who reported low physical Statistics Canada, Canadian Community activity, based on their responses to questions about the frequency, Health Survey, 2000/2001, health file (2) duration and intensity of their participation in leisure time physical activitySOCIAL DETERMINANTS OF HEALTHPostsecondary education Proportion of the population aged 25 to 54 years who had obtained a Statistics Canada, 1996 Census postsecondary certificate, diploma or degree. This is a measure of (20% sampling) (3) education attainment and socioeconomic statusUnemployment rate, 1996 Proportion of the labour force aged 15 years and older without a job in 1996 Statistics Canada, Labour Force Survey (special tabulations) (4)Low income rate Proportion of the population in economic families (a group of two or more Statistics Canada, 1996 Census (20% sample) (3) (1995 income) persons living in the same dwelling who are related to each other by blood, marriage, common-law or adoption) with incomes below the Statistics Canada low income cut-off. The cut-offs represent levels of income at which people spend disproportionate amounts of money for food, shelter and clothingIncome inequality Proportion of income (from all sources, pretax and post-transfer) held by Statistics Canada, 1996 Census (20% sample), (1995 income) households whose incomes fall below the medial household income. (special tabulations) (3) A proportion of 50% represents no inequalityHigh life stress Proportion of the population aged 18 years and older who reported a high Statistics Canada, Canadian Community level of life stress Health Survey, 2000/2001, health file (2) Continued on page 1248Can J Cardiol Vol 19 No 11 October 2003 1247
  8. 8. Filate et alAPPENDIX I (continued from previous page)OTHER COMMUNITY CHARACTERISTICSPopulation density Number of people per square kilometre. Calculated by dividing the total Statistics Canada, 1996 Census, and population by land area Geography Division (special tabulations) (3)Immigrant population All immigrants living in a geographic area, and those immigrants who Statistics Canada, 1996 Census (20% sample) (3) came to Canada from 1981 to 1996Visible minority population Proportion of the population belonging to a visible minority group. As Statistics Canada, 1996 Census (20% sample) (3) defined by the Employment Equity Act (1995) (22), visible minorities are persons (other than Aboriginal people) who are non-Caucasian in race or nonwhite in colourUrban population Proportion of the population living in urban areas. An urban area is Statistics Canada, 1996 Census (3) defined as having a minimum population of 1000 and a population density of 400 people per square kilometreAPPENDIX II REFERENCESTwo sets of three multivariate regression models were created. 1. Heart and Stroke Foundation. Incidence of Cardiovascular Disease. May 12, 2002. <> (Version current atThe first set included regression models examining the individual September 17, 2003).relationship between traditional cardiac risk factors, social deter- 2. Statistics Canada. Canadian Community Health Survey (CCHS) Cycleminants of health and other community factors and age-standard- 1.1. August 1, 2003.ized cardiovascular disease mortality, respectively. The second set 3. Statistics Canada. 1996 Census. Catalogue No. 93F0020XCB1996004. 4. Statistics Canada. Labour Force Survey. Collection registration:of models examined the relationship between the above-men- STC/LAB-035-02581.tioned factors and age-standardized ischemic heart disease mor- 5. Pickle LW, Gillum RF. Geographic variation in cardiovascular diseasetality. Community characteristics involved in the regression mortality in US blacks and whites. J Natl Med Assoc 1999;91:545-56.analyses were obtained from the first round of the Canadian 6. Mortality Atlas of Canada. Volume 2: General Mortality. Ottawa: MinisterCommunity Health Survey. Regression coefficients were reported of Supply and Services, 1980. (Catalogue No. H49-6/1-1980). 7. Mortality Atlas of Canada. Volume 4: General Mortality Patterns andfor each characteristic along with the corresponding P value. To Recent Trends. Ottawa: Minister of Supply and Services, 1991. (Cataloguekeep the analyses simple and easily interpretable, hierarchical No. H49-6/4-1991).regression modelling was not conducted. One hundred twenty 8. Bondy SJ, Jaglal S, Slaughter PM. Area variation in heart disease mortalityhealth regions were included in the analyses. Nineteen health rates. In: Naylor CD, Slaughter PM, eds. Cardiovascular Health and Services in Ontario. Toronto: Institute for Clinical Evaluative Sciences, 1999:51-62.regions with missing or suppressed data were excluded from the 9. Gillum RF. Prevalence of cardiovascular and pulmonary diseases and riskregression analyses. factors by region and urbanization in the United States. J Natl Med AssocThese health regions include: 1994;86:105-12. 10. Sundquist J, Malmstrom M, Johansson SE. Cardiovascular risk factors and the neighbourhood environment: A multilevel analysis. Int J EpidemiolNewfoundland and Labrador 1999;28:841-5. Grenfell Regional Health Services Board 11. Statistics Canada. Health Indicators, 2002. (Catalogue No. 82-221-XIE). 12. Kennedy CC, Brien SE, Tu JV. An overview of the methods and data usedOntario in the CCORT Canadian cardiovascular atlas project. Can J Cardiol Huron Public Health Unit 2003;19:655-63. 13. Béland Y, Bailie L, Catlin G, Singh MP. CCHS and NPHS – An improvedManitoba health survey program at Statistics Canada. Proceedings of the section on South Eastman Survey Research Methods, American Statistical Association. Indianapolis, Interlake August 16, 2000. 14. Tanuseputro P, Manuel DG, Leung M, Nguyen K, Johansen H. Risk factors South Westman for cardiovascular disease in Canada. Can J Cardiol 2003;19:1249-59.Territories 15. Winkelby MA, Taylor CB, Jatulis D, Fortmann SP. The long-term effects of a cardiovascular disease prevention trial: The Stanford Five-City Yukon Territories Project. Am J Public Health 1996;86:1773-9. Northwest Territories 16. Salonen JT, Puska P, Kottke TE, Tuomilehto J. Changes in smoking, serum Nunavut cholesterol and blood pressure levels during a community-based cardiovascular disease prevention program – The North Karelia Project.Quebec Am J Epidemiol 1981;114:81-94. Région du Bas-Saint Laurent 17. Melanson KJ, McInnis KJ, Rippe JM, Blackburn G, Wilson PF. Obesity and cardiovascular disease risk: Research update. Cardiol Rev 2001;9:202-7. Région du Nord-du-Québec 18. Rogers RG, Hummer RA, Krueger PM. The effect of obesity on overall, Région de la Gaspésie-Îles-de-la-Madeleine circulatory disease- and diabetes-specific mortality. J Biosoc Sci 2003;35:107-29. Région de la Chaudière-Appalaches 19. Puska P. Successful prevention of non-communicable diseases: 25 year experiences with North Karelia Project in Finland. Public Health Med Région du Nunavik 2002;4:5-7. Région des Terres-Cres-de-la-Baie-James 20. Vartiainen E, Puska P, Pekkanen J, Toumilehto J, Jousilahti P. Changes inAlberta risk factors explain changes in mortality from ischemic heart disease in Finland. BMJ 1994;309:23-7. Health Authority #5 21. Alter DA, Naylor CD, Austin P, Tu JV. Effects of socioeconomic status on Crossroads Regional access to invasive cardiac procedures and on mortality after acute Peace Regional myocardial infarction. N Engl J Med 1999;341:1359-67. 22. Statistics Canada. Total Population by Visible Minority Population (1), for Keeweetinok Lakes Regional Health Authority Newfoundland, 1996. Census (20% Sample Data) Northwestern Regional Health Authority <> (Version current at September 25, 2003).1248 Can J Cardiol Vol 19 No 11 October 2003