Is obesity a health risk, or not?

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It can be quite confusing reading research headlines in the media. It seems so many studies are contradictory; for example, you read that salt intake is bad or salt is not so bad, alcohol consumption is bad or some alcohol is good, vitamins help you live longer or vitamins do not help your health at all. What is the consumer supposed to believe? Which research results have validity and which have less impact than advertised?

A recent example of research where the conclusions were emphasized in the media was a study published in the Canadian Medical Association Journal (CMAJ) on obesity and mortality. This study followed obese Americans over two time periods of five and six years duration. It concluded that a staging system could be used to predict which obese patients are more likely to have a shortened life span, taking into account health problems other than obesity. Further, the findings were presented in the media as a potential tool to decide who most needs bariatric (weight reduction) surgery. In addition, news reports stated that the study demonstrated that obesity is not a health risk for many obese patients.

The Longitudinal Health Study from the Cooper Aerobics Institute in 1996 showed that overweight individuals could increase their life span through regular physical activity. Indeed, many non-overweight individuals have health problems and need to be more physically active. Thus, good health is not all about how much you weigh.

However, at closer look at the CMAJ study reveals some important limitations that were not reported in the press. First, the study recorded deaths up to eight years after the first patients were enrolled. It is certainly possible that this is too short of a time frame to conclude mortality risk from obesity. Next, consider the stages that the study authors found were most risky for those with obesity. These included patients with established diseases such as diabetes and end-organ damage such as stroke, heart attack and heart failure. The patients with no risk factors such as high blood pressure or the appearance of abnormalities such as rising blood sugar levels and borderline high blood pressure, were at less risk for early mortality, regardless of the body mass index. These findings seem to make good sense, the more advanced your health problems are, the higher your risk of dying.

However, what would happen to the lower risk obese patients if they were followed for 10, 20 years or longer? Would they still be at lower risk of mortality despite their obesity? Or would some of these obese patients now have Type 2 diabetes, heart attacks and severe knee osteoarthritis? Conditions such as knee osteoarthritis and Type 2 diabetes can exist initially without the patient feeling any symptoms. Since the CMAJ study partially relied on self-reporting of medical conditions, it is entirely possible that some of the obese patients had undiagnosed medical problems.

And yet, if these patients had been labelled as low priority for weight reduction surgery or told weight reduction was not necessary, their conditions would worsen over time when weight reduction could have improved or halted diseases. Once some conditions are very symptomatic such as knee osteoarthritis, they cannot be reversed. Obese individuals are four to five times more likely to develop knee osteoarthritis than non-obese individuals. Although knee replacements can help those with severe knee osteoarthritis, there are more risks associated with operating on obese individuals. Since 80 per cent of those with Type 2 diabetes are obese, the condition can be cured for many by weight loss. The problem is that if too much time passes and disease complications develop, these complications can cause permanent organ damage.

The take-home message is that you are a higher risk for developing certain health problems with obesity and these health problems can definitely lead to a reduced life span, not to mention pain and poor health during all the years of having these conditions. Chronic diseases attributed to obesity cause the patient grief and place an expensive burden on the health care system. Don't take the chance that obesity with few health issues now will result in few health problems many years later.

It is never too late to become physically active to improve your health and reduce your weight. Talk to your primary care physician or nurse about what your health risks may or may not be as an obese individual looking forward to a long life.

Dr. Maureen Kennedy MD, CCFP, FCFP, MSc, PhD(c) Kinesiology, Dip. Sport Med., is a sport and exercise medicine physician at Pan Am Sport Medicine in

Winnipeg.

Readers can ask Dr. Kennedy questions, but due to the volume of requests, replies are not guaranteed.

askthedoctor@freepress.mb.ca

Republished from the Winnipeg Free Press print edition September 6, 2011 D1