Waist circumference at five common measurement sites in normal weight and overweight adults: which site is most optimal?

The aim of this study was to determine (i) if adults would measure their own waist circumference (WC), (ii) which WC site(s) are the most intuitive and easy to measure and (iii) if measurement accuracy and association between WC and blood pressure differs across five measurement sites. Participants (n = 198) measured their WC first with no instruction and then using visual instructions for the iliac crest, last rib, midpoint, minimal waist and umbilicus. Without instruction, men most commonly measured their WC at the umbilicus and iliac crest, while women measured their WC at the umbilicus and minimal WC. Both men and women reported the minimal waist and umbilicus to be moderately easier to self-measure compared to the other sites (P < 0.05). Prevalence of abdominal obesity varied significantly by gender and measurement site, especially for females (normal weight: 0-18%; overweight: 51-79%). Measurement site did not influence accuracy of WC self-measurement or the association between WC and blood pressure (P > 0.05). A universal WC landmark is needed. From these results, there does not appear to be a clear clinical advantage in terms of blood pressure or practical advantage of measuring one WC site over another. However, the umbilicus may be the most intuitive and easy to measure.