Watch your blood pressure!

Heart and Stroke Foundation of Ontario
News Release

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A recent study by the Heart and Stroke Foundation of Ontario warns that blood pressure rates represent a significant risk to the general population and are particularly high in key ethnic groups. Results from a new study, the Ontario Survey on the Prevalence and Control of Hypertension (ON-BP) were published today in the Canadian Medical Association Journal (CMAJ).

The study by the Heart and Stroke Foundation of Ontario, the University of Ottawa Heart Institute and Statistics Canada found that in 2006, nearly 1.5 million or 21% of Ontarians are living with hypertension. Of these, more than 500,000 Ontarians were suffering from uncontrolled high blood pressure.

“Approximately 1 in 4 men and 1 in 5 women aged 20 to 79 were found to have hypertension, with the rate increasing by age,” says Dr. Frans Leenen, University of Ottawa Heart Institute and the study’s principal investigator. “Among those aged 60 to 79 years, for example, 52% were hypertensive.”

Moreover, the study found the risk is not equally distributed among all Ontarians: those of South Asian or Black descent are three times more likely to be hypertensive than the general population and are likely to develop it at a younger age.

“Knowing that hypertension rates are on the rise due to an aging and diverse population is an important wake-up call for all Canadians, including health care providers,” says Dr. Sheldon Tobe, Heart and Stroke Foundation of Ontario spokesperson. “Hypertension contributes significantly to cardiovascular and renal disease morbidity, mortality and health care costs. We must continue working towards not only improved treatment but more effective prevention.”

The Ontario Survey on the Prevalence and Control of Hypertension (ON-BP), is the first Canadian population-based study to measure blood pressures and to determine hypertension rates among some of the most common ethnic groups in Canada (South Asians, East Asians and Blacks). It is also the first study since the Canadian Heart Health Survey in the early 1990s to actually measure blood pressures, rather than relying upon participant’s self-reports. The study involved 2551 Ontarians aged 20 to 79 years in 16 communities, with the results weighted to reflect the population of Ontario.

Ethnic diversity

Although ethnic differences in hypertension rates have been demonstrated in the United States for some time, ON-BP is the first study to provide clear evidence concerning ethnic Canadians. In ON-BP, East Asians had the lowest rate of hypertension (19%) whereas South Asians and Blacks had the highest (30% and 31%, respectively). They also develop hypertension at a younger age - nearly 50% of blacks have already developed hypertension in their 40s and 50s. In comparison, the general population (primarily Caucasians) had a 21% hypertension rate.

“For some time the Foundation has been working on strategies to provide culturally-appropriate heart health information,” comments Margaret Moy Lum Kwong, Director, High Blood Pressure Strategy, Heart and Stroke Foundation of Ontario. “These new findings reinforce that we’re on the right track. Something must be done if, as a society, we are to ensure that all Canadians benefit equally from advances in hypertension prevention, diagnosis and management. If we stop this unprecedented effort, we cannot expect these results to continue. The epidemic of uncontrolled hypertension will only get worse.”

Improvements in treatment and control

Over the past decade, the Foundation, in partnership with the Ontario Ministries of Health and Health Promotion, has devoted extensive resources to public and professional education on hypertension prevention, diagnosis and management. Initiatives have included online consumer tools such as the Blood Pressure Action Plan™, resources designed to support best practices in hypertension diagnosis and management for family physicians, nurses, nurse practitioners, community pharmacists and patients in primary care, and promotion of the Canadian guidelines on hypertension management. Results from the ON-BP suggest that these efforts are paying off handsomely. In the early 1990s, only 12% of hypertensives in Ontario were both treated and controlled. In contrast in 2006, ON-BP found the rate had increased more than five-fold. The proportion of hypertensives treated and controlled did not differ significantly by ethnic group, being 66% overall with modest variations across ethnic groups.

“This rate of hypertension treatment and control is much higher than that reported in the United States in 2003/04,” says Dr. George Fodor, University of Ottawa Heart Institute and the study’s co-principal investigator, “and we suspect it may be one of the highest in the world. This is excellent news and reflects the consistent and significant efforts made in educating and supporting both healthcare practitioners and patients in pharmacological and non-pharmacological blood pressure management.”

Still more room for improvement

At the same time, Dr. Leenen went on to point out it is important to recognize that a third of hypertensives are not adequately treated and controlled: 19% of hypertensives are not being treated and another 15% of hypertensives are treated but not effectively managed. This represents a significant and important opportunity for improving the health of Canadians and reducing the health burden of hypertension.

One challenge that could undermine the progress made to date may be the obesity epidemic sweeping Canada. Statistics Canada has estimated that 36% of Canadians aged 18 and over are overweight and an additional 23% are obese. ON-BP found that compared to someone who has a body mass index (BMI) less than 25 kg/m2, those who are overweight (BMI of 25-30 kg/m2) have a two-fold greater risk of hypertension, while those who are obese (BMI greater than 30 kg/m2) have a three-fold risk. These figures suggest that 59% of Canadian adults are at a weight that increases their risk of hypertension.

The results of this survey will help the Foundation continue to refine and expand their public communication and education efforts, focusing on the diverse communities at risk, including on-line tools. The Heart and Stroke Foundation of Ontario will also be broadening their efforts around high blood pressure in the aboriginal communities with a pilot high blood pressure program in two communities (Whitefish River and Aundeck Omni Kaning).

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