A greater tendency toward sedentary activities, such as playing video games, is blamed in part for growing obesity among children. (CBC)

Doctors should start screening children for obesity starting at age six, a U.S. task force recommends.

The recommendations to doctors from the U.S. Preventive Services Task Force were published in Monday's online issue of the journal Pediatrics.

The guidelines are based on a review of 20 clinical trials of behavioural and drug treatments for obesity. The reviewers concluded there is enough evidence that behavioural interventions can prevent weight gain or support weight loss in children and young adults.

"I think this is the beginning of people understanding what works," in fighting obesity in children and young adults, said Dr. Evelyn Whitlock, the author of the research review on which the task force based its recommendation. Whitlock is also associate director at the Oregon Evidence-based Practice Center in Portland, and a senior investigator at the Kaiser Permanente Center for Health Research.

The medium- to high-intensity behavioural intervention programs reviewed were for obese children and usually were held once or twice a week for six months to a year.

The programs involved three components:

• Diet counselling.
• Organized physical activity.
• Behaviour management, such as goal-setting and problem-solving skills.

Obesity in children can't be looked at the same way as it is in adults since children are still growing, and public health officials say that preventing obesity in the first place is the priority.

But Whitlock noted doctors are also seeing more overweight and obese children — and the health consequences — in their practices. She attributed the expanding waistlines to changes in the U.S. such as:

• Fewer children walking to school.
• Lower accessibility of parks.
• A greater tendency towards sedentary behaviour, such as time spent watching TV or using computers.
• Reduced physical education programs in schools.

It seems like family doctors would address dangerous weight problems in young patients, but they often don't, said Mark Tremblay, an obesity specialist at the Children's Hospital of Eastern Ontario in Ottawa.

Weighty issue

"I think there's a discomfort on the level of many physicians and other health-care providers as well, because they're not sure how to deal with problem."

Even with the latest findings, one family doctor questioned whether there is any point in screening children for obesity.

"We've had a huge paucity of treatment programs and resources for family physicians," said Dr. Carolyn Thomson, chief of family medicine at the IWK Children's Hospital in Halifax. "So if they pick up obesity in children, where do we send them, what do we do?"

Last week, Statistics Canada reported that among young children, 17 per cent are considered overweight and nine per cent are obese — a three-fold increase in obesity since 1981. Among youth aged 15 to 19, the percentage whose waist circumference put them at an increased or high risk of health problems also more than tripled.

The report also found that Canadian children are now taller, heavier and weaker than in 1981.