Almost a third of Canadian children are either overweight or obese, says a report from Statistics Canada that bases its figures on the World Health Organization method of determining ideal weights for youth around the globe.
Using data from the 2009-2011 Canadian Health Measures Survey, Thursday’s report suggested 31.5 per cent of those aged five to 17 — an estimated 1.6 million young Canadians — are overweight or obese.
The proportion was slightly higher among younger youth. Almost 33 per cent of five- to 11-year-olds were overweight or obese, compared to 30 per cent of those 12 to 17.
The percentage of kids who were overweight — but not obese — was similar across age groups.
But when it came to those deemed obese, more boys than girls fit the WHO definition, with 15.1 per cent of boys being obese compared to eight per cent of girls.
The gender gap appears to be particularly noticeable in the five-to-11 age group, with three times more boys considered obese (19.5 per cent) than girls (6.3 per cent). The difference appeared less pronounced among those aged 12 to 17, with 10.7 per cent of boys and 9.6 per cent of girls considered obese.
It’s not clear why more boys than girls in the younger age group would be obese. Even the report’s authors footnoted the finding “use with caution.”
“It’s a new observation from our perspective, as well,” said Kim Elmslie, director general of the Centre for Chronic Disease Prevention and Control at the Public Health Agency of Canada.
“Hence the footnote around that and the need for us really to drill down on what that means, because we don’t know at this point what that means,” she said Thursday from Ottawa.
“So what we really need to do next, and what we will be doing next, is further analysis to understand why are we seeing this difference in the five-to-11-year age group between boys and girls?”
Experts say the proportion of Canadian kids and teens who are overweight or obese has not changed much in the last few years. What has changed is the method for determining if a child or teen is carrying too many pounds and to what extent.
The traditional estimate of overweight and obese youth — 26 per cent — has been primarily determined from International Obesity Task Force (IOTF) criteria, based on body mass index (BMI) measurements.
The new report uses WHO’s more recently implemented weight status charts, also BMI-based, which many medical associations now endorse.
“More people met the threshold based on those new guidelines, so it looks like there’s a jump up in the number of kids who are overweight or obese,” said Dr. Mark Tremblay, director of Healthy Active Living and Obesity Research at Children’s Hospital of Eastern Ontario in Ottawa.
Tremblay, who was not involved in penning the federal report, said it’s unlikely the proportion of overweight and obese kids has suddenly escalated by five or six percentage points.
“No, it’s really just a measurement issue,” he said. However, he conceded “we may have been underestimating in the past using the IOTF method how many kids that was.”
Elmslie said the WHO classification system helps public health officials understand the optimal growth trajectory for children and how that should be applied for measuring obesity rates in the population overall.
“The IOTF would result in a rate of one in four and WHO would result in a rate of one in three children (being overweight or obese),” she said.
“What’s important, however, is that whether it’s one in four or one in three, it’s too high.”
Tremblay said the rise in childhood obesity is related to a “drifting in lifestyle behaviours” that favour sedentary pastimes such as sitting in front of the computer over physical activities like play and sports.
“And those behaviours at some level represent a misuse or a disuse of our muscles, our heart, our lungs and so on. And so they atrophy or they degrade or manifest problems at an earlier age.”
He said there has been an acceleration in the age of onset of chronic diseases in young people who are inactive and saddled with extra weight.
Increasingly, doctors are seeing kids with risk factors for cardiovascular disease, Type 2 diabetes and mental health issues — “things we would not expect and in previous generations would not have observed,” he said.
“This is the concern, that to some degree, we’re mortgaging the health of this younger generation.”
Dr. Catherine Birken, a spokeswoman for the Canadian Paediatric Society, said a 2012 position paper by the organization provides guidelines to promote active, healthy living to prevent obesity among young people.
Birken, a staff pediatrician at Toronto’s Hospital for Sick Children, said there is a strong link between obesity and sedentary behaviour like screen time, and it’s critical that children and adolescents boost physical activity and cut down on sedentary pursuits.
“Obesity is a very important and prevalent problem in Canada, and in children particularly,” she said. “So children who are obese are more likely to be obese as adults.”
Birken said childhood obesity is related to a host of complications, among them mental health issues, poor self-esteem, bullying and depression.
There are also physical consequences to obesity, including Type 2 diabetes, abnormal cholesterol levels, high blood pressure and obstructive sleep apnea.
“I treat children with obesity,” said Birken. “So absolutely we’re seeing more and more children struggling with obesity and the complications of obesity.”
The StatsCan report is one more piece of research looking at the prevalence of overweight and obese youngsters across the country, which many pediatric health experts say has reached epidemic proportions.