Puberty a gateway to heart disease for Canada's teens

A seven-year ongoing study examining over 20,000 Canadian grade 9 students shows most already have at least one major risk factor for heart disease and stroke, Dr. Brian McCrindle told the Canadian Cardiovascular Congress 2009, co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society. "This study is further evidence of an accelerating decline in the heart health of Canada's teens," says Dr. McCrindle, a cardiologist at The Hospital for Sick Children in Toronto. "Children shouldn't have these profiles."

The study investigated the heart health of 20,719 grade 9 students aged 14 and 15 years.

The study found that, between 2002 and 2008, the rates of high blood pressure, high cholesterol, and obesity in these teens were alarmingly high and, even more worrisome, increasing over time.

Risk factors of Canadian 14 and 15 year olds
Grade 9 students with 2002 2008 Increase from 2002 to 2008
One or more cardiovascular risk factors 17% 21% +4%
High blood pressure 19% 17% -2%
Elevated cholesterol levels 9% 16% +7%
Obesity 11% 13% +2%

"It is shocking that one in five 14 and 15 year olds has high blood pressure," says Heart and Stroke Foundation spokesperson Dr. Beth Abramson. "What does this say for the future health of these young teens? They are at risk of developing long-term health effects such as premature heart disease and type 2 diabetes."

High blood pressure is the leading cause of stroke and a major risk factor for heart disease. "We're ringing the alarm bell. Every child has the right to grow up healthy," says Dr. Abramson.

The teens' elevated cholesterol rates had the greatest increase, accelerating from nine to 16 per cent in six years. "An increase of this magnitude in this age group is astonishing," says Dr. Abramson. "These risk factor levels will continue to increase and track into adulthood unless we do something now. These children are in grave danger."

Dr. McCrindle says the situation could be even worse than it looks. There is a synergistic relationship between risk factors.

"One of the things we already know is that it is the number of risk factors you have that really accelerates the whole process," he says. "And when you have a healthy looking kid in front of you, it's easy to miss the invisible time bomb waiting do go off."

Lifestyle factors of Canadian 14 and 15 year olds
Grade 9 students' levels of 2002 2008 Change from 2002-2008
Physical activity
(Physically active for 90 minutes at least five days a week) 28% 22% -6%
Sedentary behaviour
(20 or more hours per week of TV or video games) 22% 24% +2%