Doctors are the University of Alberta - along with doctors across Canada - are warning of a hidden complication in obese children that could be fatal if left untreated.

Doctors say obesity hypoventilation syndrome or OHS occurs when fat tissue lodges in the upper airways, affecting the breathing of a child with obesity.

A cross-Canada study has been launched in an effort to identify children who may be affected by OHS.

“It’s an opportunity to increase awareness and tell people about the problem and identify it in children so we can help them,” said Dr. Manisha Witmans with the University of Alberta.

“What the study gives us an opportunity to do is contact pediatricians and other physicians across Canada to see how many children in their practice might have this problem so we can get an idea of who these children are, how they’re affected and where they might be living.”

Details on obesity hypoventilation syndrome were published in this month’s issue of Paediatrics & Child Health.

The report said OHS is “almost certainly under-recognized and under-reported” in children and if left untreated, it can cause “major complications” including congestive heart failure, respiratory failure and even death.

The University of Alberta is among the research and health centres taking part in the two-year study launched under the Canadian Paediatric Surveillance Program and Witmans says it could be the beginning of an even bigger study.

“We’re hoping it will be the first step to a more national, wider study to look at specific parameters or things about these children in an effort to try and help them, treat them more systematically and comprehensively,” she said.

Witmans says if a child is obese and also shows signs of sleepiness during the day or have behavioural problems, the child may have OHS.

“The hard part as the clinician or doctor or even the parent that might see this child, all you see is someone who is overweight or heavy and not motivated to go to school, get out of bed, tired in the morning, sleepy all the time, would be things to watch for,” she said.

Researchers are advising parents and doctors to report children they believe may suffer from OHS.

Concerned parents are told to contact their respective physicians and have their children evaluated.

Approximately 26 per cent of Canadian children aged two to 17 are considered overweight or obese.