Angina and Socio-Economic Status in Ontario: How Do Characteristics of the County You Live in Influence Your Chance of Developing Heart Disease?

Article excerpt

ABSTRACT

Objective: To assist in the development of community heart health programming and policy development, the Central West Health Planning Information Network (CWHPIN) was asked by its partners to collaborate in obtaining information that might clarify the relationships between socio-economic status (SES) and heart disease among residents of Ontario, Canada. The purpose of this component of the project was to explore, at the county level, how much of the variation in angina pectoris (angina) could be explained by SES variables.

Study Design: Linear regression modeling was used to identify key predictors of angina hospitalization rates in counties Ontario-wide.

Results: Results of the linear regression modeling showed that SES variables (most notably education and occupation) were key predictors of angina, even when traditional risk factors (i.e., smoking, etc.) were included in the analysis.

Conclusion: This study demonstrates that, at the county level, socio-economic variables such as education and occupation have a significant relationship with rates of heart disease at the population level, even when including the traditional risk factors in the analysis.

Cardiovascular disease (CVD) is a leading cause of mortality throughout most of the world. This situation is true in Canada, where it is estimated that one in four (close to eight million) Canadians have some form of cardiovascular disease.1 Cardiovascular disease was the leading cause of mortality (30.4%) in Ontario in 1996.2 This burden of illness exacts a significant toll on the Canadian population in terms of disability and economic costs. As such, methods for ameliorating this burden remain a top public health priority.2,3

Cardiovascular disease represents a broad category of conditions that affect the heart and circulatory system. The largest component of CVD is ischemic heart disease (IHD). IHD is a term applied specifically to the symptomatic narrowing of the coronary arteries by atherosclerotic changes.2 IHD includes angina, which presents as chest pain resulting from decreased blood supply to the heart.4 Prolonged angina can lead to an acute myocardial infarct or heart attack (AMI). Hospitalization rates for angina, by county in Ontario (1992/931996/97), ranged from 154 to 535 per 100,000 (See Figure 1).

It is well accepted that factors such as physical inactivity, hypertension, smoking, diabetes, high blood cholesterol levels, and having a Body Mass Index (BMI) greater than 27, contribute to higher mortality and morbidity rates, but together, are able to explain only about 30% of the variance in CVD.5 Recently, strong evidence has emerged from work by a number of researchers6-8 that supports the argument that socio-economic status (SES) is an important independent risk factor in the etiology and progression of heart disease. The purpose of this paper was to discover the extent to which the variability in angina hospitalization rates could be explained by SES variables and lifestyle risk factors.

In Ontario, Public Health Units (PHUs) are required by the Ministry of Health and Long-Term Care (MOHLTC) to implement programs and initiatives designed to decrease deaths from heart disease. Currently, strategies suggested for reducing CVD relate primarily to traditional risk factors like smoking, a high fat diet, and physical inactivity. Further insight into which socio-economic risk factors and or combinations of risk factors influence local rates of illness is required. This evidence may lead to further research and contribute new knowledge to support effective, broadbased heart health promotion programming and policy development.

METHODS

Data for this investigation were analyzed for Ontario's 49 counties, districts, and municipalities (Table I). The best Ontario-wide data sources available for this study were ecological measures at the county level. Data on angina hospitalization rates were obtained from the Institute for Clinical and Evaluative Sciences' (ICES) Atlas on cardiovascular health and services in Ontario. …