Friday, September 21, 2012

Obesity higher in boys than girls: study

A StatsCan report has found that close to a third of young people in Canada are classified as overweight or obese. 
A StatsCan report has found that close to a third of young people in Canada are classified as overweight or obese.

Canada's boys are three times more likely than girls to be obese, according to new research that is exposing alarming and lopsided gender differences in the nation's childhood obesity rates.

A new Statistics Canada report finds that 19.5 per cent of boys aged five to 11 are obese, compared to 6.3 per cent of girls of the same ages.

Experts say that it's long been recognized that obesity tends to occur in higher rates in boys than girls, "but certainly not as in-your-face as those numbers are," said Dr. Katherine Morrison, medical director of the metabolism, obesity and health program at McMaster Children's Hospital in Hamilton, Ont.
"I don't recall levels looking at three times higher, as we're seeing here," she said.

Overall, the study found that close to one-third of young people - 31.5 per cent or 1.6 mil-lion youth in Canada - were classified as overweight or obese. The study was based on actual measured heights and weights of 2,123 children and adolescents in Canada, aged five to 17, between 2009 and 2011.

Though the estimates haven't changed significantly over the last decade, the authors said more research is needed to know for certain whether the once fast-rising pace of obesity is slowing.

"Regardless, the estimates remain high and are a public health concern, given the tendency for excess weight in childhood to persist through to adulthood," they write.

Excess weight in childhood is increasingly being linked to ill-nesses once only seen in adults, including "adult-onset" Type 2 diabetes, high blood pressure, abnormal blood fats, abnormal blood clotting, thickening of the arteries and non-alcoholic fatty liver disease. Studies have shown that adolescents who are overweight have a 14-fold increased risk of having a heart attack before they turn 50.

Children with obesity also have higher levels of depression and low self-esteem. They're more likely to be teased or bullied at school.

In the new study, 19.8 per cent of the five-to 17-year-olds were classified as overweight in 2009 to 2011, and 11.7 per cent were obese. The percentage that was overweight was similar across age groups.
More profound was the difference between boys and girls.

Overall, 15 per cent of boys were obese, compared to eight per cent of girls. But the gender split was most pronounced at ages five to 11.

Part of the difference relates to new World Health Organization standards that were used to measure obesity; doctors say the old standard was known to underestimate obesity.

But the new cutoffs alone aren't enough to explain away the three-fold difference in obesity rates reported among five-to 11-year olds, experts say.

Screen time - time spent in front of a TV, computer, video game and smartphones - is strongly linked with childhood obesity. Children who spend two hours or more with screens per day are twice as likely to be overweight or obese than those who took up one hour or less. Studies have shown that screen time is higher among boys than girls. Children as young as five are using hand-held game consoles.
"We also know that kids eat while they watch, and they eat what they watch," said Dr. Tom Warshawski, head of pediatrics at Kelowna General Hospital and chair of the Childhood Obesity Foundation.
"They're heavily marketed and exposed to unhealthy foods and beverages."

But McMaster's Morrison also wonders, "Is there some under-lying biological differences in terms of how the environment is impacting males and females regarding obesity? This sort of begs that question, that you're seeing it so young."

In her clinic, Morrison sees 11-year-old boys with weights "up into the 170-to 180-pound range."
In a study published two years ago, more than 60 per cent of 860 pediatricians and family doctors in Canada surveyed identified parents who are overweight themselves as fundamental barriers to curbing the numbers of children who are growing up overweight.

Morrison said she isn't reluctant to raise the issue of parental responsibility. "But it's how it's raised," she said. "Parents, obviously their role is to try and do the best within their family, and I honestly believe that is the motivation of the parents I see. ... They don't wish this on their children, and they hope they can do it somehow differently."

Some observers caution that the study didn't measure fat. "It could be that the boys have increased muscle mass to fat mass for a given BMI (body mass index) than the girls," said Robert Ross, professor in the school of kinesiology and health studies at Queen's University in Kingston, Ont.

Ross said it's a positive sign that overall rates of obesity among children appear to be levelling off. What's not clear, he said, is, "have we stopped the bleeding, or is this a blip on the screen?"

Either way, "we're nowhere near where we want to be. We have prevalence rates that are sky high," Ross said. "Our children may not live as long, and as well, as we will," he said. "Where is the outrage?"

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