Measuring obesity to assess cardiovascular risk--inch tape, weighing machine, or both?

waist circumference (WC), waist-to-hip ratio (WHR)] are used to define obesity, the debate as to which is the best to assess CVD risk continues. While direct assessment of fat mass may be a better index of obesity-related to health risk, it is difficult to measure this accurately in large epidemiological studies particularly in the field setting. Thus, anthropometry still remains the most widely used method for clinical and epidemiological purposes. Each obesity index has its own implications in relation to health risk in general and CVD risk in particular. In the study by Gupta R, et al,8 the importance of BMI, WC and WHR are all shown to be important for estimating CVD risk due to their positive association with various CVD risk factors. Survey of the literature also shows that no single obesity index can be recommended for this purpose from a global standpoint. The recent INTERHEART study showed that waist-tohip ratio was a much better predictor of CVD events than BMI9 and the accompanying Lancet editorial is provocatively titled “A farewell to body mass index? ”. 10 Indeed, INTERHEART also showed for the first time that not only is waist a ‘risk’ factor, but that hip is an independent ‘protective’ factor. Hence the WHR becomes an even stronger marker because the numerator (waist) is a ‘risk’ factor while the denominator (hip) is a ‘protective’ factor and therefore the ratio is, at least theoretically, a stronger predictor than either alone. However, while waist itself is difficult to standardize, measuring hip is even more challenging as one needs to undress the subject and, in the case of women, this could pose cultural and logistic problems eg. finding enough privacy, women health workers to perform measurements etc. Moreover, many studies report that WC is as good if not better than using WHR11 and it is much simpler as it needs standardization of only one measurement.9,12-14 While proponents of BMI would point out the difficulties in standardization of WC and WHR, we would argue that measuring BMI needs not only a weighing machine, but also a stadiometer to measure height. Standardization of the latter is a major problem particularly in rural areas where even the floor is not uniform, while calibration of weighing machines, particularly the spring balance which is commonly used, would always remain an epidemiologist’s nightmare. Moreover, the sheer convenience of carrying a measuring tape in one’s pocket or purse for doing *Chairman and Chief of Diabetology, Madras Diabetes Research Foundation and Dr. Mohan’s Diabetes Specialities Centre 4, Conran Smith Road, Gopalapuram, Chennai 600086, India Asian Indians have an increased predisposition not only to diabetes1 but also to premature coronary artery disease.2 This has been attributed to the so called ‘Asian Indian Phenotype’3,4 characterized by less of generalized obesity as measured by body mass index (BMI) but greater central body obesity as shown by greater waist circumference (WC) and waist-to-hip ratios (WHR). 3,4 This leads to unique biochemical and hormonal changes including higher plasma insulin levels, greater insulin resistance, lower HDL cholesterol, higher triglyceride levels, increased small dense LDL cholesterol as well as small dense HDL cholesterol and C-reactive protein and leptin levels but decreased adiponectin levels.4-7 Thus many Asian Indians fit into the category of metabolically obese, normal weight individuals.