A Profile of Cardiovascular Disease in Northern Ontario: Public Health Planning Implications

Transcription

1 A B S T R A C T Cardiovascular disease (CVD) is a leading cause of death in Northern Ontario and therefore considered an important issue. To this end, this paper examines CVD trends in Northern Ontario and the prevalence of known risk factors that give an insight into these trends. Ontario Health Survey 1990, Ontario Health Survey 1996, Canadian Institute for Health Information ( ) and Vital Statistics ( ) were examined. It was determined that CVD rates in Northern Ontario significantly exceeded those of the province. Further, high prevalence of modifiable risk factors, such as smoking, fat intake, physical inactivity and obesity are all experienced in Northern Ontario when compared to the province. Planning implications, as they relate to collaboration, delivery of services, determinants of health, multiple risk factors and monitoring and evaluation are also discussed. A B R É G É Les maladies cardiovasculaires (MCV) sont l une des principales causes de décès dans le nord de l Ontario et, par conséquent, constituent un problème important. À cet effet, l article examine les tendances des MCV dans le nord de l Ontario et la prévalence des facteurs de risques connus qui permettent de mieux comprendre ces tendances. L article a fait une analyse de l Enquête sur la santé en Ontario de 1990, de l Enquête sur la santé en Ontario de 1996, des données de l Institut canadien de l information sur la santé ( ) et des Statistiques vitales ( ). L article établit que le taux des MCV dans le nord de l Ontario dépasse largement la moyenne provinciale. De plus, l article constate que, dans le nord de l Ontario, il existe une forte prévalence de facteurs de risques modifiables comme le tabagisme, le régime riche en gras, l inactivité physique et l obésité comparativement à ce qu on trouve en Ontario. L article aborde également des questions reliées à la planification, à l offre des services, aux déterminants de la santé, aux facteurs à risques multiples, à la surveillance des tendances et à l évaluation. A Profile of Cardiovascular Disease in Northern Ontario: Public Health Planning Implications Vic S. Sahai, MSc, 1 Robert C. Barnett, MA, 2 Colette R. Roy, BSc, 3 Shelley A. Stalker, BA, 4 Vinod N. Chettur, MS, 5 Shehnaz Alidina, BScOT, MHA 6 Over the past century, remarkable progress has been made in improving the health status of people living in Ontario. However health measures of the past, which have proven themselves effective at combatting infectious diseases, have not had the same impact on today s leading causes of death and disability. Although these leading causes of death (cancer, cardiovascular disease [CVD] and injuries) are non-infectious in nature, they are nevertheless preventable. 1-3 Of these epidemics, CVD causes the most death, disability and illness and is the second leading cause of Potential Years of Life Lost (PYLL) in Ontario after cancer. 4 The economic cost, both direct 5 and indirect, 6 is enormous and the individual and societal impact is highly significant. While there has been some progress made against CVD in Ontario, the mortality rates remain high relative to international benchmarks. 7 This is especially true in the northern part of the province where the rates have remained well above the provincial average. Northern Ontario has traditionally higher rates of experienced risk factors associated with CVD; for example, 1. Director, Northern Health Information Partnership, Sudbury, ON 2. Senior Analyst, Northern Health Information Partnership 3. Project Coordinator, Northern Health Information Partnership 4. Research Assistant, Northern Health Information Partnership 5. Senior Information Consultant, Northern Health Information Partnership 6. Consultant, Sudbury, Ontario (MHA Fellowship in Health Administration) Correspondence: Mr. Vic Sahai, Director, Northern Health Information Partnership, 199 Larch Street, Suite 1104, Sudbury, ON, P3E 5P9 Tel: , Fax: , sahai@nhip.org Northern Health Information Partnership is funded by the Ontario Ministry of Health and Long-Term Care. smoking, physical inactivity, and dietary fat intake have been higher in the northern part of the province. The geography, population characteristics and the rural-urban mix all combine to set Northern Ontario apart from the rest of the province. As is typical of remote and rural areas of Canada, lack of access to health care and public health services makes prevention difficult. 5 In order to develop effective and efficient prevention strategies for Northern Ontario, it is necessary to obtain relevant information pertaining to CVD for this area. The objectives of this study are as follows: 1) To examine CVD trends in Northern Ontario; 2) To identify the occurrence of variance in disease rate relative to those of the province; 3) To identify the occurrence of known risk factors associated with CVD; 4) To suggest some potential public health planning strategies for Northern Ontario. DATA SOURCES The following data sources were used to complete this study: 1) Census (1996): Data collected by Statistics Canada in the 1996 Census. 8 2) Ontario Health Survey 1990 & 1996 (OHS 90 & OHS 96): The OHS 90 and 96 are province-wide population surveys that were administered to households throughout Ontario. Full description of the methodology can be obtained elsewhere. People living in institutions, on Native reserves and in extremely remote locations were not included in the survey. 9,10 NOVEMBER DECEMBER 2000 CANADIAN JOURNAL OF PUBLIC HEALTH 435

2 3) Canadian Institute for Health Information ( ): In this report, hospital separation records were collected by the Canadian Institute for Health Information (CIHI). 11 4) Vital Statistics ( ): Records of deaths are collected, compiled and stored by the Office of the Registrar General. DATA ANALYSIS The data were obtained via the Ontario Ministry of Health Provincial Health Planning Database, Frequencies of cases were obtained using GQL - Hummingbird Corporation. 13 Age-specific and crude rates were reported. Agestandardized mortality/morbidity rates (Direct Method) with corresponding 95% confidence intervals (Table I and Figure 1) were also reported and calculated in accordance with the methods described by Armitage and Berry. 14 There were no statistical tests performed as the confidence intervals are provided to show significance. The 1991 Canadian Census population was used as the standard population. GEOGRAPHY Northern Ontario is made up of two very large geographical areas covering eighty percent of Ontario s landmass. Northeastern Ontario contains the districts of Algoma, Cochrane, Manitoulin, Muskoka, Nipissing, Parry Sound, Sudbury District, Sudbury Regional Municipality, and Timiskaming. Northwestern Ontario encompasses the districts of Thunder Bay, Rainy River and Kenora. The two northern areas are geographically and culturally distinct. 8 For example, Northwestern Ontario has a much greater Aboriginal (Table II) population relative to Northeastern Ontario. The health data are not collected by ethnicity, therefore we cannot say that the higher mortality/morbidity rates are a result of a large Aboriginal population in the North. For these reasons we choose to report the statistics for the two northern areas separately to point out any potential differences in their health status. RESULTS TABLE I Risk Factors of Cardiovascular Disease, Weighted Percentage*, & 95% Confidence Intervals Variables Ontario Northwestern Northeastern Ontario Ontario Current Cigarette Smokers - Both Genders (Years) (12,13) (16,26) (21,23) (26,26) (38,44) (38,40) (20,22) (26,34) (28,30) (11,11) (10,20) (10,12) Overall (21,22) (31,33) (29,31) Current Cigarette Smoker Males (23,23) (31,37) (32,34) Females (19,19) (27,33) (27,29) Regular Physical Activity - Both Genders - Three or more times/week (Years) (71,72) (69,80) (75,81) (61,61) (60,67) (62,66) (58,59) (59,68) (53,59) (54,55) (44,58) (48,55) Overall (60,61) (61,66) (61,63) Body Mass Index > 27: Ages Both Genders (27,29) (34,36) (33,37) Males (27,29) (39,43) (38,42) Females (21,22) (27,31) (27,31) Degree to which life is very/fairly stressful - Ages 12+* Both Genders (49,51) (46,52) (43,47) Males (51,53) (46,54) (43,47) Females (48,50) (44,52) (44,48) Over 30% Calories from Fat per day* Both Genders (73,75) (77,81) (76,80) Males (75,77) (80,86) (77,81) Females (72,74) (72,78) (75,79) Consumes Five or More Vegetables & Fruits per day - Ages 12+* Both Genders (36,38) (33,37) (35,38) Males (37,39) (32,38) (34,38) Females (36,38) (32,38) (35,39) * Ontario Health Survey 1990 Ontario Health Survey % confidence intervals are stated in parentheses Mortality Over the years 1984 to 1995, the rate of CVD had been steadily decreasing, especially in males. However, the male rate still remains higher relative to its female counterpart (Figure 1). In Northern Ontario, CVD is the leading cause of death. Between the years , CVD accounted for 40% of female deaths (6,602) and 40% of male deaths (7,474). Ischemic heart disease (includes both Other IHD and Acute Myocardial Infarction ) accounted for the greatest percentage of these deaths (55.6% for females [2,096 deaths] and 63.4% for males [2,597 deaths]), of which approximately half are attributable to heart attacks (Figure 2). 436 REVUE CANADIENNE DE SANTÉ PUBLIQUE VOLUME 91, NO. 6

3 TABLE II Demographic and Socio-Economic Health Factors Factors Ontario Northeastern Northwestern Proportion of Population with Grade Nine or Less Years of Schooling 10% 13.5% 13% Female Average Employment Income $22,000 $16,000 $19,000 Male Average Employment Income $34,700 $30,800 $33,000 Incidence of Low Income of Population in Private Households 18% 18% 12% Unemployment Rates for Females Ages % 12.2% 10.2% Unemployment Rates for Males Ages % 14.0% 12.0% Aboriginal Population* 1.3% 5.6% 14.4% * In the 1986 Census, many First Nations people boycotted the census. Thus, an accurate count was not taken. In the 1996 Census, the undercounts remain a problem. Source: Statistics Canada, 1996 Census RISK FACTORS Smoking There are more smokers in Northwestern Ontario (32%) and Northeastern Ontario (30%) compared with Ontario (21%). Smoking rates also vary by age, with year olds having the highest rates (Northeastern Ontario - 39%, Northwestern Ontario - 41%, Ontario - 26%). There is little difference in the overall smoking rates of men and women. In Northern Ontario, there is a significantly higher proportion of women smoking relative to women living in Ontario (Table I). Figure 1. Age-standardized Mortality Rates per 10,000 population: Cardiovascular Disease (ICD-9 CODE ) Source: Registrar General, Vital Statistics Figure 3 indicates that the two northern regions, particularly Northeastern Ontario, have significantly higher age-adjusted mortality rates than do the southern regions and the province as a whole. Potential years of life lost Despite the higher mortality of CVD in Northern Ontario, the trends are similar to the rest of the province. CVD is the second leading cause of premature death in Ontario after cancer. In 1995, cancer was responsible for 1,045,968 potential years of life lost (PYLL) while CVD was responsible for 683,869 PYLL. In Northern Ontario, CVD is the third leading cause of premature death (72,886 PYLL), the first being injuries and poisoning (93,402 PYLL) and the second being cancer (91,258 PYLL). 5 Hospital separations The hospitalization results are displayed in Figure 4. The northern regions had consistently higher hospital separation rates relative to the province as a whole. Also, males were more likely to be hospitalized relative to their female counterparts. The CVD readmission rates for the North ( ) is 23.4% and is comparable to the provincial rate of 20.4%. Therefore, the rate difference cannot be explained by readmission of the same people. 12 Physical inactivity Despite the presence of longer winters in Northern Ontario, the proportion of the population that participates in physical activity three or more times a week is roughly equivalent to the provincial norm. Age is also associated with level of physical activity in general. Younger age groups tend to exercise at a greater rate than the older age groups. (Table I) Nutrition Canada s Food Guide recommends 5-10 servings of vegetables and fruits daily. Vegetables and fruits are known to contain compounds that alter or prevent the development of cancer and/or heart disease. 15 In the OHS 90 data, 44% of respondents reported consuming at least the minimum five servings of vegetables and fruits per day. Table I gives a more detailed breakdown of these data by gender. The overall Ontario trends are seen across the North. Fat intake Table I shows that over three quarters of the people living in Ontario consume NOVEMBER DECEMBER 2000 CANADIAN JOURNAL OF PUBLIC HEALTH 437

4 more than 30% of calories from fat in the diet (the recommended maximum intake). This percentage was significantly greater in the North. 9 Unfortunately, data on saturated fats in the diet were not available. Injuries and Po is on ing % Digestive Disease % Others % Male Other IHD % Cerebrovascular % Obesity Obesity is interrelated with both diabetes and high blood cholesterol, and is also more prevalent in Northern Ontario than in the rest of the province. The obesity indicator used in the OHS 96 was a Body Mass Index (BMI) greater than 27 (The National Population Health Survey 1996 uses the following criteria for levels of obesity: (i) some excess weight = BMI 25-27, and (ii) overweight = BMI>27). Thirtyfive percent of residents of Northeastern Ontario and 35% of residents of Northwestern Ontario are obese compared to the provincial average of 28%. Prevalence of obesity is significantly greater among men than women (Table I). 9 Stress While stress plays an important role in the etiology and pathogenesis of CVD, stress levels are reported to be lower in Northeastern Ontario (45%) and Northwestern Ontario (49%) than in Ontario as a whole (50%) (Table I). Shift work Knutsson has shown that shift work and CVD are associated. 16 This is true for both genders. 17 Although there are no data on shift work in Ontario, the OHS 90 asked the following question which can be used as a proxy indicator: Does your job or business require you to work rotating shifts? In the North, 30% of the respondents answered yes in comparison to 20% of their southern counterparts, representing a significant difference in rates. 9 Socio-economic health factors Lower education, lesser income and employment status play varying roles in determining health status. These indicators have also been found to vary with higher rates of smoking, diabetes, a greater tendency to be overweight, lower physical activity, higher levels of blood cholesterol and high blood pressure. 18,19 It has been shown that adult occupational status is Respiratory Diseas e % Neoplas ms % Injuries and Po is on ings % Digestive Disease % Respiratory Dis ease % Figure 2. Age adjusted mortality rates per 10, Figure Others % Neoplasms % inversely associated with current smoking, leisure time, physical activity and obesity Cardiovascular Disease % Female Cardiov ascular Dis ease % Acute Myocardial Infarc tion % Other IHD % Acute My oc ardial Infarction % Arteries % Others % Hy pertensive % Cerebrov as cular % Arteries % Others % Hypert ensive % Leading Cause of Death Percentage and Standardized Rates of Death per 10,000 Population, Northern Ontario Sources: Statistics Canada and Registrar General of Ontario Ontario Toronto Central West Central East East Central South 28.5 Southwest Northwestern Northeas tern Age-adjusted Mortality Rates for Ontario Planning Regions (per 10,000) and 95% Confidence Intervals for all Deaths and Diseases of the Cardiovascular System ( ) Sources: Statistics Canada and Registrar General of Ontario risk factors (low status-high risk). 20 The majority of the socio-economic health fac- 438 REVUE CANADIENNE DE SANTÉ PUBLIQUE VOLUME 91, NO. 6

5 health interventions such as education, environmental support and policy development, the impact of CVD can be lessened. Success, however, depends on individuals, communities, organizations, businesses and government working together. Collaboration Districts in the North share many similarities in terms of risk factors and disease burden. Mechanisms should be set in place to allow agencies with a heart health mandate to collaborate effectively on common problems and solutions. Figure 4. tors for Northeastern and Northwestern Ontario fall short of the provincial average. For example, the Northern rates for employment, education and income are lower when compared to the provincial rates (Table II). Diabetes Diabetes is a predisposing factor to CVD. Residents of Northern Ontario make more visits to hospitals because of diabetes than do their Southern counterparts. In 1996, the hospital utilization rate for males was 1.61 per 1,000 in Northeastern Ontario, 1.38 per 1,000 in Northwestern Ontario compared to 0.92 per 1,000 for Ontario. The hospital utilization rate for females was 1.80 per 1,000 in Northeastern Ontario, 1.59 per 1,000 in Northwestern Ontario compared to 1.17 per 1,000 for Ontario. 5 LIMITATIONS Hospital Discharges: Cardiovascular Disease by Year and Gender per 1,000 Population Northern Ontario Source: Canadian Institute for Health Information The OHS 90 represents one of the most significant undertakings ever to measure health status in Ontario. While more information is available from the OHS 96 of the National Population Health Survey (NPHS ), recent information concerning some risk factors related to CVD are not included in the OHS 96, which makes comparison very difficult. Because of the time lag in the reporting of Census, CIHI and Vital Statistics data, the most recent information is not available for analysis. CIHI and Vital Statistics do not have an ethnic variable and therefore the effects of ethnicity cannot be quantified. DISCUSSION AND PLANNING IMPLICATIONS CVD is the leading cause of death in Northern Ontario, accounting for approximately 40% of all deaths. Not only does this take a personal cost from its victims, but also a monetary cost. CVD results in billions of dollars per year in health care expenditures as well as lost productivity. CVD also has one of the highest indirect costs of all disease categories in Canada: 6 that is, the loss of future earnings from premature death and the value of lost productivity from illness or disability. This paper demonstrates that cardiovascular mortality observed in Northern Ontario exceeds similar provincial rates. The higher mortality rates most likely reflect a greater incidence of CVD disease in the North, which may be linked to the high levels of risk factors. Further to this, high prevalence of modifiable risk factors for CVD is experienced in Northern Ontario. By reducing these risk factors through public Delivery/treatment of services Treatment service forms an important component in the continuum of care for CVD. The large geographical area, harsh winters, and poor driving conditions make it difficult to travel long distances in Northern Ontario thus creating challenges both in the accessibility and the delivery of services. Further to this, the lack of critical mass results in a lack of human resources and technology for CVD services in many Northern communities. As a result, many Northern Ontario communities do not have the full range of cardiovascular services. Therefore, community development and mobilization approaches must be used to develop and deliver heart health programs across a vast area. Determinants of health Factors such as income, employment, and poverty should be taken into account in the development and delivery of heart health programs. Further, health professionals should be leading advocates in policy development for these areas. Multiple risk factors Many individuals have more than one risk factor for CVD. Therefore, a multifactorial approach comprising education, environmental support and policy development should be considered to simultaneously address a variety of factors. Monitoring and evaluation Regular monitoring, evaluation and benchmarking assist in determining the effectiveness of heart health programs. The information has stimulated public action; NOVEMBER DECEMBER 2000 CANADIAN JOURNAL OF PUBLIC HEALTH 439

6 in much the same way the evaluation will be the force that consolidates the results of this initiative. It is important that timely, accurate and consistent baseline data be collected. These data are necessary to track mortality and morbidity, the prevalence of modifiable risk factors and the socioeconomic and environmental conditions. ACKNOWLEDGEMENT The authors thank the members of the Northern Heart Health Steering Committee who contributed their invaluable constructive input. REFERENCES 1. Robertson LS. Injury Epidemiology Research and Control Strategies. Oxford: Oxford Press, Schottenfeld D, Fraumeni JF (Eds.). Cancer Epidemiology and Prevention 2 nd Ed. Oxford: Oxford Press, Mormat M, Elliott P (Eds.). Coronory Heart Disease Epidemiology. Oxford: Oxford Press, Ontario Ministry of Health. Opportunities for Promoting Heart Health. Report of the Chief Medical Officer of Health. Toronto: Queen s Printer for Ontario, Northern Health Information Partnership, Cardiovascular Disease in Northern Ontario: A Quantitative Profile, November Chan B, Coyle P, Heick C. Economic impact of cardiovascular disease in Canada. Can J Cardiology 1996;12(10); Moore R, Mao Y, Zhang J, Clarke K. Economic burden of illness in Canada, 1993: Executive summary and recommendations. Chronic Disease in Canada 1997;18(2): Statistics Canada, Statistical Profile of Canadian Communities: Area Profiles, Ontario Ministry of Health. Ontario Health Survey 1990, Volume II. Toronto, Ministry of Health, Statistics Canada, National Population Health Survey (NPHS), Ministry of Health. Ontario Health Survey Toronto. 11. World Health Organization, Manual of the International Statistical Classification of Diseases, Injuries and Causes of Death, Ver.9, Geneva, Ontario Ministry of Health. Ontario Ministry of Health Provincial Health Planning Database. Toronto: Queen s Printer of Ontario, Hummingbird Communication Ltd., GQL 4.2 Enterprise Query and Reporting. North York, Armitage P, Berry G. Statistical Methods in Medical Research Second Edition. Boston: Scientific Publications, Steinmetz KA, Potter JD. Vegetables, fruit and cancer prevention: A review. J Amer Diet Assoc 1996;96: Knutsson A. Shift work and coronary heart disease. Scand J Sco Med Suppl 1989;44: Kawachi I, Colditz GA, Stampfer MJ, et al. Prospective study of shift work and risk of coronary heart disease in women. Circulation 1995;92(11): Klompas N, Shapiro C. Patients working shifts: Treating the chronic effects. Can J Diagnosis 1998;February 1998: Ontario Ministry of Health. Ontario Health Survey 1990 Highlights. Toronto, Brunner E, Shipley MJ, Blane D, et al. When does cardiovascular risk start? Past and present socioeconomic circumstances and risk factors in adulthood. 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