Obesity Prevalence in Canada

(from Peter T. Katzmarzyk, School of Physical and Health Education, Dep't of Community Health and Epidemiology Queen's University, Kingston, Ontario.Published in the Canadian Medical Ass'n Journal, January 17, 2006)

Obesity places a substantial burden on public health in Canada, and people with more extreme levels of obesity are at substantially increased risk of premature death.

A framework issued by Health Canada gives guidelines for body weight classification. Overweight is considered with a BMI of 25 or greater. Obese is if the BMI is 30 or greater. Then obesity is further separated into 3 classes according to the increased health risks associated with increasing BMI levels: class 1 (BMI 30-34.9), class 2 (BMI 35-39.9) and class 3 (BMI >40). These guidelines help direct treatment options from dietary restriction to increased physical activity or more aggressive therapy such as pharmacotherapy or bariatric surgery (generally reserved for extreme obesity of class 2 or 3), or have additional health risk factors.

In this study the prevalence's of overweight and all levels of obesity in Canada have increased between 1985 and 2003. They found that the prevalence of class 3 obesity increased form o.4% to 1.3% between 1990 and 2003, a 225% increase. This trend is similar to that reported in a US study. However, the absolute prevalence of class 3 obesity in Canada remains lower than that in the United States. (there are no comparable data from Europe).

These estimates are likely conservative, since people tend to underestimate their own weight.

The increases in prevalence of overweight and all levels of obesity in Canada between 1985 and 2003 are cause for concern given the markedly increased risk of premature death and of metabolic and musculoskeletal complications arising from morbid obesity. The rapid increase in the prevalence's of class 2 and 3 obesity will undoubtedly have as significant impact on our health care system.