Waist Ratios (WHR / WHtR)

Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Across 31 studies WHtR outperformed BMI and waist circumference for identifying hypertension, diabetes and dyslipidaemia, supporting a simple boundary value of 0.5.

WHO expert consultation (2008) waist-to-hip ratio cut-offs for substantially increased risk: ≥ 0.90 in men and ≥ 0.85 in women. NICE recommends using waist-to-height ratio alongside BMI, with 0.5 as the action point and ≥ 0.6 indicating substantially increased health risk. Measure the waist midway between the lowest rib and the iliac crest, and the hip at the widest point, with the tape snug and horizontal. These indices are less validated in pregnancy, marked skeletal deformity, and some ethnic groups.