Foreign-born youth have a lower body mass index (BMI) than Canadian-born youth, says a new study from researcher Atif Kukaswadia in the Department of Public Health Sciences, under the supervision of Dr. Will Pickett and Dr. Ian Janssen.

Additionally, these differences in BMI did not disappear in the years after immigration, with East and Southeast Asian youth consistently having a lower BMI than Canadian youth.

Using the theory of acculturation, the team were correct in their expectation that children born to foreign parents in Canada would have a higher BMI. This theory states that the longer immigrants are in the host country, the more they take on that country’s cultural values and lifestyle.

“Canada has an obesogenic lifestyle – a lifestyle rich in influences that promote obesity in individuals or populations - and we expected that this would influence children born here, whether their parents are immigrants to Canada or not,” says Mr. Kukasawadia. “These findings stress the importance of considering both ethnicity and country of birth when designing and implementing weight-loss interventions.”

The study used data from the 2009/10 Health Behaviour in School-Aged Children Survey, a survey of over 26,000 youth in grades 6 -10 in all Canadian provinces and territories except Prince Edward Island and New Brunswick. The general health survey included questions about topics from physical activity to drug/alcohol use and peer relationships.

“Canada receives between 250-300,000 immigrants each year and 10 per cent of them are below the age of 14,” says Mr. Kukaswadia. “We were interested in what happens to their health after they move here, specifically their physical activity and BMI.”

The research teams organized youth into the following ethnic groups: Canadian (European, North American and Aboriginal), Arab and West Asian, East Indian and South Asian, Each and Southeast Asian, Latin American and other (mixed ethnicity).

“We had 3 main findings,” says Mr. Kukaswadia. “Firstly, children born abroad had a lower BMI than those born in Canada; secondly, average BMI differed by ethnic groups; finally, East and South East Asian children consistently had a lower BMI than Canadian children with no differences based on where they were born.”

Moving forward, Mr. Kukaswadia and his team hope to further study why BMI is so different between Canadian and foreign-born youth.

This research titled, “Influence of country of birth and ethnicity on body mass index among Canadian youth: a national survey” was published in the Canadian Medical Association Journal Open. The Canadian Health Behaviour in School-Aged Children study (Principal Investigators: John Freeman and William Pickett) was funded by the Public Health Agency of Canada and Health Canada. This analysis was supported by the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada. Atif Kukaswadia was supported by a Canadian Institutes of Health Research Frederick Banting and Charles Best Canada Graduate Scholarships Doctoral Award. Ian Janssen was supported by a tier 2 Canada Research Chair in Physical Activity and Obesity.