Overweight and obesity (excess adiposity) are associated with an increased risk of diabetes, arthritis, cardiovascular disease, and certain cancers [1–3]. Over the past twenty years the prevalence of overweight and obesity has risen sharply in many countries [4–7]; and cheap, straightforward techniques for population surveillance of adiposity remain critical. In large epidemiological studies measuring adiposity almost always relies on proxy measures such as the body mass index (BMI) .
There is evidence, that proxy measures of central adiposity – waist circumference (WC) and waist to hip ratio (WHR) – are better predictors of adverse health events, including mortality, than BMI [9–11]. A tape measure is also an easier piece of equipment to carry into the field than a stadiometer and a set of weighing scales. Notwithstanding these advantages BMI remains the adiposity metric of choice in most medical research. In 2011, for instance there were 13,909 papers listed in PubMed related to BMI and less than one fifth as many papers related to WC or WHR (n = 2,422).
One factor affecting the adoption (or lack of adoption) of WC or WHR may be the current reliance on inexpensive self-reported BMI measures, and the concomitant uncertainty among the research community about the validity of self measured waist and hip data. Self-reported height and weight, which is used to estimate BMI, has been widely used e.g., [12, 13]; and the validity and biases associated with self-reported height and weight have been the subject of considerable research since at least the 1980s . These have included, for instance, validity studies from Asia [15–17], North America , Central America , and Europe .
In contrast there are relatively few validity studies of self measurement associated with WC and WHR, and with one exception , the studies all appear to have come from Europe and North America [21–31]. The lack of validation studies on self measurement of WC and WHR from different populations with different anthropometry, cultural practices, and levels of education will necessarily affect the adoption of WC and WHR as alternative measures of adiposity in medical research. The generalisability of the studies are further affected by variations in the choice of tape measure including paper [22, 30, 31], cloth or plastic , marked or unmarked , or constant tension tape measures ; differences in the device used by participants and technicians ; the instructions provided; the presence or absence of light clothing; and the sampling frame (clinical, community, occupational, random, convenience, and so forth).
In this research, we contrasted self measurement and assisted measurement of waist and hip circumference and WHR in a community-based sample from a district town in peninsular Malaysia, using a now standard protocol . We also examined the validity of the measures for scientific research; specifically we examined the extent to which the measurement approach affected statistical relationships with BMI, diastolic and systolic blood pressure, and non-fasting blood glucose. While the need for validation is critical, the research was relevant also to explore the feasibility of self measurement within a context where the permissibility of data collectors taking these measurements is constrained by cultural and social mores.