Canadian children and teens leaner than decade ago

Fewer Canadian children tipped the scales as overweight in 2013, according to an new analysis of Statistics Canada data, and doctors say that's an encouraging sign after years of increases.

Introduction of new charts helped health care providers to discuss a child's growth with parents

Fewer Canadian children tipped the scales as overweight in 2013, according to a new analysis of Statistics Canada data, and doctors say that's an encouraging sign after years of increases.

It's important to tackle childhood obesity because it can progress into adulthood and lead to elevated blood pressure, an increased risk of Type 2 diabetes and other health issues. In adults, the ramifications of excess weight can include heart attacks and strokes.

As a clinician, Dr. Celia Rodd of the department of pediatrics and child health at the University of Manitoba has seen the impact of those high rates in the clinic and hospital. 

To learn more, Rodd and co-author Dr. Atul Sharma analyzed Statistics Canada data on 14,014 young people three to 19 years old using the World Health Organization's 2010 revised growth charts adapted for Canada.

They were pleased to find a recent decline in the prevalence of overweight among Canadian children and teens, based on the body mass index (BMI) of measured heights and weights, and body fat levels for girls and boys. 

In 1978, about a quarter of children were overweight or obese and six per cent were obese. By 2004, the rate of overweight or obese had jumped to about a third and the obesity rate doubled to 12 per cent, using current WHO charts and national survey data.

In this week's issue of the Canadian Medical Association Journal, Rodd and Sharma also report:

  • Overweight or obesity decreased from 30.7 per cent to 27 per cent between 2004 and 2013.
  • Obesity rates hit a plateau at 13 per cent. 

The findings mean the decrease occurred in the overweight category only, not obesity.

"This is still encouraging because this was only over a decade and it is harder to reverse more severe disease," Rodd said in an email interview.

Although average scores for BMI declined as children were leaner, the scores were still higher than for those in the WHO reference group, the researchers said in warning against complacency.

"Few if any other jurisdictions have demonstrated a plateau let alone a decline," Rodd said. "It is hard with the data on hand to tease out all the reasons why this might be happening in Canada."

 Prevention takes root?

Media attention and the creation of individual-, family- and community-centred programs for children could be playing a role, the authors speculated.

What's more, since 2000, physicians and health care providers could turn to BMI growth curves to use as a tool when discussing a child's growth.

The data also suggested Canadian children had less central adiposity (or belly fat) than historic or current groups of American children. Abdominal obesity, or fat that accumulates in the belly or within abdominal organs as a muffin top or spare tire, is considered worse than other fat in terms of risk of cardiovascular complications.

Rodd suggested parents:

  • Help choose healthy foods and avoid food with little nutritional value.
  • Continue to think about how to keep their children active.
  • Ask their physician or health care provider if their child's BMI is appropriate.

It's important to think of children as a canary in a coal mine, Rodd said in a journal podcast, and to make changes to help the child, and think about how to get adult family members to eat better and exercise more, too.

Mark Tremblay, director of the Healthy Active Living and Obesity Research program at the Children's Hospital in Eastern Ontario in Ottawa, was not part of the research. He previously published on 2004/2005 data from Statistics Canada for a smaller age group.

Tremblay responded to the results with cautious optimism, given the results look encouraging yet levels of BMI, overweight and obesity are still high and concerning.

"If this is a real trend, and not some manifestation of analytical or methodological limitation or selection bias, it may reflect a variety of things: increased public health awareness, reduced energy intake, increased energy expenditure, improved preventive health care — evidence that the many efforts being made by many groups and sectors over many years now may be finally taking root — let's hope," Tremblay said in an email.  

The researchers weren't able to examine regional or racial differences. Since the data was cross-sectional in nature, no cause and effect relationships can be drawn.

Poland, Australia, the Netherlands, Germany and Denmark have showed small declines or plateaus in obesity rates, previous studies suggest.

The University of Manitoba study was funded by the Children's Hospital Research Institute of Manitoba.