Wednesday, February 03, 2010
Last Friday I discussed the Canadian Health Measures Survey (CHMS), which I feel is among the most important surveys in the world of health research (along with its American counterpart, the National Health and Nutritional Examination Survey). The CHMS is nationally representative and has directly measured physical activity and physical fitness, not to mention every type of medical test under the sun, which allows researchers to examine questions that would just not be possible any other way. Friday I discussed the results of the CHMS paper which focused on the health of Canadian children, today I'd like to focus instead on the health of Canadian adults. I discussed the study design in detail last week, so today I'd like to jump straight into the results.
As you might expect, the trends seen over time in adults are similar to those seen in children. In comparison to 1981 (the last time that a survey with similar measures was performed), present-day middle-aged Canadian men are almost 20 lbs heavier, while women are about 12 lbs heavier. Equally worrying, both genders have added an extra 2.5 inches to their waist girths. Similar to Canadian youth, Canadian adults are also significantly less flexible, and have less muscle strength than in 1981. The authors also note that these reductions have real clinical consquences.
Currently, the average 20- to 39-year old man and woman are overweight and have the same body composition profile as those who were aged 40 years or older in 1981. If these trends continue for another 25 years, half of males and females over the age of 40 years will be obese (BMI 30 kg/m2 or more), with commensurate increases in the personal and economic burden of avoidable noncommunicable disease.
In 1981, the typical 45-year-old man and woman had grip strength values of 104 kg and 62 kg, respectively. These values are 10 kg and 6 kg (around 10%) lower in the typical 45-year-old of today. Temporal changes in grip strength of this magnitude at the population level are meaningful. To put this into context, the results of a 25-year prospective cohort study of grip strength and physical disability risk (such as slow walking speed, unable to stand from chair) in middle-aged males found that between-group differences in grip strength that were comparable to the temporal changes between the CFS and the CHMS were associated with about a twofold increased risk of developing physical disability over the follow-up period.
In other words, there is a good chance that the average Canadian adult has twice the risk of developing physical disability as in 1981. Scary stuff. Strangely, some, like the Globe and Mail, have suggested that these declines really are not that big a deal. Since the average Canadian still scores in the "good" range for aerobic fitness, they conclude that "Maybe, then, the effects of the alleged obesity epidemic are exaggerated.", and go so far as to suggest that "no real evidence indicates" that the current generation won't outlive their parents (what qualifies as "real evidence", they do not say).
Unfortunately, the Globe and Mail is almost certainly wrong, and we are most likely in the midst of a public health crisis. However, we are fortunate, because Dr Mark Tremblay (one of the researchers behind the CHMS and Director of the Healthy Active Living and Obesity Research Group at the Children's Hospital of Eastern Ontario Research Institute) was the subject of a feature interview last weekend on the CBC News with Peter Mansbridge, and that video can be seen in its entirety here. The video is about 20 minutes long, and it is well worth watching on your lunch break (after your twenty minute walk around the office, of course!). If you are looking for a terrific synopsis of the obesity epidemic, its societal impact, and what we can do about it, then I highly recommend you check out the video. Unfortunately I can't embed it on our site, but if you click the still image below it will take you directly to it.
Or, you can listen to the audio version of the interview using the embedded media player below (email subscribers will have to visit Obesity Panacea to view the media player). And to access the original CHMS paper yourself, please click here.
Shields, M, Tremblay, MS, Laviolette, M, Craig, CL, Janssen, I, & Connor Gorber, S (2010). Fitness of Canadian adults: Results from the 2007-2009 Canadian
Health Measures Survey Health Reports, 21 (1), 1-15
Enjoyed this story? Share it with your friends by clicking the buttons below!
To get future posts delivered directly to your email inbox or to your RSS reader, be sure to subscribe to Obesity Panacea.