Hypertension or high blood pressure is projected to affect more than a quarter of Canadian adults within two years, a new study says.

About six million, or 23 per cent, of Canadians were living with diagnosed hypertension four years ago, the study in Monday’s issue of the Canadian Medical Association Journal finds. 

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Hypertension accounts for about 13 per cent of all deaths, Canadian researchers say. (Lucy Nicholson/Reuters)

When blood pressure is too high, it puts stress on the body's entire vascular system, forcing the heart to work harder.

It accounts for about 13 per cent of all deaths, Cynthia Robitaille of the Public Health Agency of Canada and her co-authors said.

Hypertension increases the risk of death from a variety of causes, including heart disease and stroke. Left untreated, hypertension can also increase the risk of dementia and kidney failure.

To determine how common hypertension is, Robitaille's team looked at data on 26 million people aged 20 and older between 1998 and 2008.

Slightly more women (24.3 per cent) than men (21.7 per cent) had the condition.

"We forecast that about 26.5 per cent (7.4 million) of Canadian adults will be living with diagnosed hypertension by 2012-13,"the study's authors wrote.

"Programs to improve the lifestyles of Canadians, such as the proposed initiative to reduce sodium consumption, will be critical to decrease the incidence and prevalence of diagnosed hypertension in Canada."

The prevalence and incidence of hypertension were highest in Atlantic Canada, after taking age into account. The pattern was consistent with east-to-west differences reported in Canadian studies of risk factors such as obesity and diabetes, the researchers noted.

A previous study suggested that about 17 per cent of Canadian adults with hypertension are unaware of their condition, which means the latest projections are likely underestimates, the authors said.

The study was conducted by researchers from the Public  Health Agency of Canada, Public Health Ontario, the  University of Calgary, the Institute for Clinical Evaluative Sciences in Toronto, the British Columbia Ministry of Health Services, the Manitoba Centre for Health Policy and Quebec's public health institute.