And sedentary behaviour ?like watching television ?was strongly correlated with being overweight, he adds.
Along with this alarming finding is one that runs contrary to what the research team expected. Surprisingly, as consumption of candy and chocolate increased, the likelihood of being overweight decreased.
"This does not mean that eating sweets in large quantities is recommended for young people," says Dr. Janssen, pointing out that the frequency of candy eating, rather than total amount consumed, was surveyed. While difficult to explain, the dietary results only underline the importance of focusing on physical activity rather than food intake as the primary way to combat overweight and obesity, the researcher emphasizes.
"The adolescent obesity epidemic is a global issue," concludes the paper, which appears in the May issue of Obesity Reviews, a journal of the International Association for the Study of Obesity. "Increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth."
The study is based on statistics gathered in 2001-2002 by the World Health Organization's Health Behaviour in School-Aged Children report, which surveyed more than 160,000 young people aged 11, 13, and 15 years in Europe and North America. The Canadian component of the WHO initiative was coordinated by Dr. William Boyce of Queen's Social Program Evaluation Group (SPEG).
Also on the research team from Queen's are Drs. Peter Katzmarzyk (Physical & Health Education) and Will Pickett (Community Health & Epidemiology). Other members come from the other participating countries of the Health Behaviour in School-Aged Children survey.
As well as placing fourth overall for obesity (at 4.1 per cent), Canadian youth ranked fifth for "overweight" (19.3 per cent). The three countries with the highest prevalence of obesity were Malta (7.9 per cent), the United States (6.8 per cent), and England (5.1 per cent). The highest prevalence of overweight youth was found in Malta (25.4 per cent), the U.S. (25.1 per cent), and Wales (21.1 per cent).
Noting that no Asian or African countries were included, the study says it is very disturbing that in 77 per cent of the countries examined, at least 10 per cent of youth were overweight, and in 20 per cent of the countries, at least 3 per cent were obese.
"The fact that similar associations were found across countries and cultures demonstrates the robustness of these findings," says Dr. Janssen. "Physical activity interventions should be a fundamental component of health campaigns aimed at reducing the global obesity epidemic."