The challenges of accurate waist and hip measurement over clothing: Pilot data

Background: Accurate waist and hip measurement are increasingly central to the goal of weight control and the battle against diabetes and cardiovascular disease. Protocols and methods vary widely, with little guidance on clothing. This pilot study investigated the effect of light clothing on measurement.

Aims: To determine whether light clothing and underwear make a potentially clinically significant difference of 0.5 cm to the measurement of waist and hip circumference in a group of volunteer subjects.

Methods: We measured waist circumference over light clothing and then over bare skin. We measured hip circumference over light clothing and then over underwear and with a small sub-group, on bare skin.

Results: 50 volunteers were measured. Potentially clinically significant differences were found in the mean values as followed (mean; 95% CI): light clothing compared to bare skin at the waist (0.50 cm; -1.54 to 2.55 cm); light clothing compared to underwear at the hip (2.58 cm; -0.75 to 5.91 cm).

Conclusion: This study demonstrates that the effect of clothing on waist and hip measurements is not always trivial, and deserves a larger study. Waist circumference measurements should be made on bare skin whenever possible and hip circumference measurements over underwear.