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Canadians of South Asian and black descent are three times as likely to suffer from high blood pressure as East Asians or Caucasians, and they are far more likely to develop the condition at a younger age, according to a groundbreaking new study.

The research is the first to examine ethnic differences in hypertension in this country and the first in-depth look at the breadth of the problem in the general population in a generation.

The findings, published in today's edition of the Canadian Medical Association Journal, are a mixed bag of good and bad news. For example:

High blood pressure, the leading risk factor for heart disease, is commonplace, affecting one in four men and one in five women;

Hypertension rates increase with age, rising from 3.4 per cent in the 20 to 39 age group to 51.6 per cent in the 60 to 79 age group;

The number of adults being treated for high blood pressure has jumped 60 per cent in a decade;

About 85 per cent of those with high blood pressure are aware of their condition and most are being treated successfully;

The death rate among hypertensives has fallen by 15 per cent in the past decade.

"Hypertension is not beaten but we're making significant progress," Frans Leenen, director of the hypertension unit at the University of Ottawa Heart Institute, said in an interview. He is the lead author of a study involving 2,551 Ontario residents, all of whom had their blood pressure measured.

Dr. Leenen said education of physicians and doctors about the importance of measuring and controlling blood pressure has made a tremendous difference.

Notably, 66 per cent of people with high blood pressure are controlling their condition with medication, up from a mere 12 per cent in 1992.

Back then, 67 per cent of hypertensives were untreated. Today, that rate is less than 20 per cent.

"The drip, drip, drip technique has finally had an impact," Dr. Leenen said.

A person is considered hypertensive with a blood pressure reading of 140/90 millimetres of mercury (mmHg) or higher. Healthy adults should have a blood pressure in the range of 120/80 mmHg, although that target varies with age and other health conditions.

Blood pressure is a measure of the force of the blood against the blood vessel walls. It is expressed in two numbers: Systolic pressure, the upper number, is the pressure when the heart contracts; diastolic pressure, the lower number, is the pressure when the heart is relaxed.

Salima Habib was only 24 when she measured her blood pressure on a lark. The results were shocking: 145/110 mmHg. She immediately saw a doctor and began treatment.

For the past six years, Ms. Habib, a bank worker in London, Ont., has controlled her blood pressure with medication, exercise and diet (notably limiting her salt intake). While she is young and thin, she still struggles with hypertension, in large part because of genetics.

"Hypertension isn't just an old person's disease any more," Ms. Habib said.

Ross Feldman, director of clinical pharmacology at the Robarts Research Institute in London, Ont., and a spokesman for the Heart and Stroke Foundation, said the prevalence of hypertension is rising throughout the population because of increasing rates of obesity and diabetes, the aging population, the changing ethnic makeup of Canada and the excessive levels of salt in the typical Canadian diet.

"It's an epidemic coming," he said.

Dr. Feldman noted that, based on current data, the vast majority of people are at risk of developing hypertension if they live past the age of 50.

He said the control rate in Canada - where two in three people control their high blood pressure with medication - is extraordinary because of a big push by consumer groups, physicians and public health agencies, but that success is probably unsustainable in the long term.

As a result, there must be a more sustained focus on preventing high blood pressure, Dr. Feldman said. "We know this can be done. The question is: Do we have the will and the resources to sustain the effort?"

Karen Tu, a scientist at the Institute for Clinical Evaluative Sciences, also stressed that "prevention is the ideal."

Her research, also published in today's edition of the Canadian Medical Association Journal, showed that the number of Ontario adults with hypertension more than doubled in the past decade.

The study - based on physician-diagnosed hypertension - found that 2.3 million Ontarians have high blood pressure, which suggests that more than six million people nationwide are hypertensive.

Cardiovascular disease is the leading cause of death in Canada, claiming 72,338 lives in 2004, the most recent year for which statistics are available.

That means that, approximately every seven minutes, someone in this country dies of heart disease or stroke.

High blood pressure: Good and bad news

Though more Canadians are treating and controlling high blood pressure than ever before, doctors warn that an aging population, obesity, diabetes, excessive salt intake and the changing ethnic makeup of Canada point to an oncoming hypertension epidemic.

CANADIAN HEART HEALTH SURVEY 1992: ONTARIO

Treated and controlled; 12.1%

Treated and not controlled; 20.8%

Not treated; 67.1%

ONTARIO SURVEY ON THE PREVENTION AND CONTROL OF HYPERTENSION 2006

Treated and controlled; 65.7%

Treated and not controlled; 14.7%

Not treated; 19.5%

TRISH McALASTER/THE GLOBE AND MAIL; SOURCE: CANADIAN MEDICAL ASSOCIATION