Being correct about obesity

To the Editor: Van Der Weyden states that “obesity” has negative connotations and the capacity to stigmatise.1 “Intending to give minimal offence and shifting the focus from the person to the condition”, people substitute politically correct terms.1

Medical practice should be scientifically, rather than politically, correct. Language aside, obesity is a blind spot in clinical practice because of the lack of any useful and accurate measure to categorise the condition. Body mass index (BMI) is the universal standard, but it is a very flawed measure. The results of epidemiological studies that support its use depend on huge population numbers, ethnic homogeneity and the exclusion of confounders including smoking and coexisting chronic disease. There is an absence of any epidemiological data showing that reducing overweight or obesity improves outcomes, despite them being frequently cited as risk factors. However, bariatric surgery has been shown to reduce cardiovascular disease, diabetes and cancer incidence.2

Central obesity is a much more powerful predictor of total mortality and cardiovascular disease mortality than BMI.3 In particular, the waist-to-hip ratio (WHR) is useful in population studies, showing precision and a lack of bias over a wide range of ethnic groups.4 Waist circumference is a better predictor than BMI but, like BMI, requires ethnic-specific criteria and is difficult to implement in today’s multiracial societies.

WHR performs better as a predictor of cardiovascular disease than all lipid fractions, including total cholesterol and low-density lipoprotein cholesterol.3,5 Lowering lipid levels by drug therapy in the clinical trial setting reduces cardiovascular end points by 20% to 25%. In this context it is pertinent to note that the cost of subsidising prescriptions for lipid-lowering drugs in the financial year 2009–10 was almost $1.5 billion.6

In contrast, there is no simple prescription available to reduce levels of obesity. Healthy eating will always be important. And to make an impact on obesity, 60–90 minutes of moderate physical activity daily is required,7 but the importance of exercise is constantly overlooked and underprescribed. Studies in the United States show that physical activity, recorded daily, reduces cardiovascular disease mortality by about 37%–53%.8 Japan has undertaken an ambitious campaign to identify and counsel employees with excessive waistlines.9 This initiative will be followed with interest. A public health focus on early identification and prevention of central obesity is therefore at least as important in reducing cardiovascular disease mortality as is the measurement and treatment of lipids and hypertension.

People with central or abdominal obesity have a serious health hazard and should be informed. “Political correctness” describes a practice that avoids giving offence to minorities. In view of the current epidemic of obesity, the language that we use should be explicit.