Asthma affected an increasing number of Canadian children in the late 1990s, but kids with the disease wheezed through fewer asthma attacks than those in years before.

According to a Statistics Canada study released Wednesday, the rate of children with asthma aged 11 and younger rose about 2 per cent between 1994/1995 and 2000/2001, translating to almost 70,000 additional asthma cases.

Numbers from 1994/1995 indicate about 11 per cent of kids aged 11 and younger had asthma at that time. The rate rose to 13 per cent over six years, bringing the number of Canadian kids with asthma to about 590,000.

Children younger than age 5 and those aged 10 and 11 were most affected by the increase, according to the study, titled "Changes in the prevalence of asthma among Canadian children."

Appearing on CTV's Canada AM on Wednesday, Dr. Sheldon Spier of the Alberta Children's Hospital described the incidence of asthma like this:

"If you look at a class of 30 kids (there are) five or six kids with asthma in the class... If you're watching a hockey game, one kid on each side has asthma."

But while the rates went up, fewer of those included in the recent figures reported having had an asthma attack in the past year. In 1994/1995, slightly more than half of asthmatic children reporting attack symptoms in the past year. That dropped to 39 per cent in the recent group studied.

"The likelihood of having had an asthma attack depended on the severity of the disease," said the study, which analyzed data from the National Longitudinal Survey of Children and Youth. "Among children with asthma, the proportion with high-severity symptoms dropped from 41% in 1994/1995 to 36% in 2000/2001."

The likelihood of developing the disease was higher for boys, children in the Maritimes and kids living with smokers.

According to the United States' Centre for Disease Control and Prevention, asthma is a lung disease that causes repeated episodes of wheezing, breathlessness, chest tightness, and nighttime or early morning coughing.

"Asthma can be controlled by taking medicine and avoiding the triggers that can cause an attack," states the CDC website.