Although both the USA and Canada are concerned about the rise in obesity and overweight prevalence during the last twenty years, in the USA the rate is over 10 percentage points higher, according to the National Center for Health Statistics, part of the Centers for Disease Control and Prevention (CDC), USA. 24.3% of Canadian adult males are obese, compared to 32.6% in America, a difference of more than 8 percentage points. 23.9% of Canadian women are obese compared to 36.2% in the USA, a difference of over 12 percentage points.
The authors explain that obesity has become a global health concern. Since the early 1960s, as part of NHANES (National Health and Nutrition Examination Survey), data on people's height and weight have been gathered in the USA. Similar data have been collected from nationally representative population samples less often in Canada. In 2007 Canada launched the CHMS (Canadian Health Measures Survey), with similar aims to NHANES. The authors add that this report aims to compare obesity estimates in the USA and Canada (among adults).
Obesity is divided into three BMI (Body Mass Index) categories because of their varying health risks:
- Obesity Class I - A BMI of between 30 and 34.9
- Obesity Class II - A BMI of between 35 and 39.9
- Obesity Class III - A BMI of 40 or more
Prevalence of obesity among adults aged between 20 and 79 in Canada and the USA, 2007-2008:
- Obesity Type I - both sexes overall, Canada 24.1%, USA 34.4%
- Obesity Type I - females, Canada 23.9%, USA 36.2%
- Obesity Type I - males, Canada 24.3%, USA 32.6%
- Obesity Type II - both sexes overall, Canada 5.8%, USA 8.8%
- Obesity Type II - females, Canada 7.2%, USA 11%
- Obesity Type II - males, Canada 4.5%, USA 6.6%
- Obesity Type III - both sexes overall, Canada 3.1%, USA 6%
- Obesity Type III - females, Canada 4%, USA 7.6%
- Obesity Type III - males, Canada 2.2%, USA 4.3%
Canadian and US obesity trends over the last 20 yearsAccording to figures collected from NHANES, 1988-1994, USA, and CHHS (Canadian Heart Health Surveys) 1986-1992, there had been a considerably sharper rise in obesity rates during those years compared to previous periods in. "The magnitude of the increases was fairly similar in the two countries."
Among American males the obesity prevalence rate grew by 12 percentage points compared to 10 in Canada (among females, 10 in the USA and 8 in Canada). Figures followed similar paths over the 20-year period across age groups in both nations.
"Adult Obesity Prevalence in Canada and the United States"
Margot Shields; Margaret D. Carroll, M.S.P.H.; and Cynthia L. Ogden, Ph.D.
NCHS Data Brief - Number 56, March 2011 (Centers for Disease Control and Prevention)
Written by Christian Nordqvist