Canada sees progress in war on obesity as overweight rates drop among children

Nationalpost.com
May 9, 2016
By Sharon Kirkey

For the first time in more than a generation, overweight rates among Canadian children are falling - raising hopes Canada may become one of the first countries to turn the childhood obesity epidemic around.

New figures show the combined rate of overweight and obesity among three- to 19-year-olds fell to 27 per cent in 2013, from nearly 31 per cent a decade earlier.

The rate fell faster among girls than boys, and among younger children compared with teens.

However, while both weight and body-mass-index scores decreased overall, the proportion of children classed as obese - those at the highest risk of diabetes-related kidney failure, non-alcoholic fatty liver disease and other weight-related health problems - held steady, at about 13 per cent over the 10-year study period.

“Even though we haven’t seen a decline (in obesity rates) we did see a plateau,” said co-author Dr. Atul Sharma, a pediatric kidney doctor and biostatistician at The Children’s Hospital of Winnipeg.

“We’ve stabilized - and we’re very happy to have stabilized that, because it was exploding.”

Still, it’s harder to turn more severe cases around, and with a quarter of Canadian children still heavier than is healthy, “we can’t become complacent,” Sharma said.

“It’s not over yet - the numbers are still too high and the burden of illness is considerable.”

Between 1978 and 2004, rates of overweight and obesity among Canadian children soared, to about 35 per cent from 23 per cent. “That was the epidemic,” Sharma said. “When those results were published in 2004, it was quite shocking, and prompted a lot of intervention at many levels.”

We may now be seeing the payoff.

For the new study, Sharma and lead author Dr. Celia Rodd, a pediatric endocrinologist who works with children with diabetes, looked at data on just over 14,000 children taken from national health surveys, in which heights and weights were directly measured.

There were equal numbers of boys and girl; 80 per cent were white. They were representative samples of children from all regions and socio-economic classes.

The researchers used 2010 World Health Organization growth charts for Canada. Based on those charts, if a child is above the 85th percentile - meaning he or she is heavier than 85 per cent of their age- and sex-matched peers - they’re considered overweight. Children above the 97th percentile are classified obese.

Compared with toddlers, older children had lower BMI scores. Girls had lower scores than boys. But most of the improvements occurred largely among children aged five to 12.

“It’s the younger children, not the adolescents, who have dropped their body-mass-index scores considerably,” Sharma said.

It’s hard to tease out exactly why, from census and survey data.

One factor might be growth charts for BMI that were introduced for the first time by the U.S. Centers for Disease Control in 2000.

“Really only 15 years ago did we acquire a tool where we could sit down with a family and say, ‘this is where your child falls on the normal spectrum,’ ” Sharma said.

Weight is a sensitive and touchy subject, he added, and when so many other children are overweight it can be hard for parents to see a problem in their own child. “It gave us a non-confrontational way of engaging the family in discussions around overweight or obesity.”

In addition, prevention and weight management programs - many of them aimed at younger children - “sprang up all across the country” after the scope of the epidemic became clear in 2004. “At all levels the discussions led to action,” Sharma. “We’re seeing the effect of those programs.”

But some of the poor eating or exercise habits were already laid down in those children who are now teens.

In the mid 1980s, “close to zero per cent” of children had Type 2 diabetes, the kind normally only ever seen in adults and that’s related to lifestyle and being overweight.

Today, close to 30 per cent of Rodd’s patients at her Winnipeg clinic have Type 2 diabetes. “It’s a terrible disease at any age, but the children who develop it younger are exposed to it longer,” Sharma said. “With time, they develop all the terrible complications - blindness, amputations and kidney failure.”

Sharma is seeing children on dialysis because of diabetes-related kidney failure. “We’re seeing hypertension due to overweight,” he said.

While others have compared Canadian and American obesity rates using BMI scores, the Winnipeg team went further and looked at waist circumference. They found Canadian children have less central, or belly fat, than American children even 20 years ago.

In addition, a study published last week showed that while rates of childhood obesity and overweight plateaued in the U.S., there has been no decline in any age group. Overall, rates of overweight and obesity combined in children remained at about 30 per cent, a rate that would be higher using WHO criteria. “Thus, Canada appears to be faring better than the U.S. in the war on obesity,” Sharma and Rodd write in the Canadian Medical Association Journal.

However, the authors stressed that more should be done to address the socio-economic drivers of obesity, including poverty and food insecurity.