A simple cut-off for waist-to-height ratio (0·5) can act as an indicator for cardiometabolic risk: Recent data from adults in the Health Survey for England

Abstract

The National Institute for Health and Care Excellence (NICE) has acknowledged the value of waist-to-height ratio (WHtR) as an indicator for 'early health risk'. We used recent UK data to explore whether classification based on WHtR identifies more adults at cardiometabolic risk than the 'matrix' based on BMI and waist circumference, currently used for screening. Data from the Health Survey for England (4112 adults aged 18+ years) were used to identify cardiometabolic risk, indicated by raised glycated Hb, dyslipidaemia and hypertension. HbA1c, total/HDL-cholesterol and systolic blood pressure (BP) were more strongly associated with WHtR than the 'matrix'. In logistic regression models for HbA1c ≥ 48 mmol/mol, total/HDL-cholesterol > 4 and hypertension (BP > 140/90 mmHg or on medication), WHtR had a higher predictive value than the 'matrix'. AUC was significantly greater for WHtR than the 'matrix' for raised HbA1c and hypertension. Of adults with raised HbA1c, 15 % would be judged as 'no increased risk' using the 'matrix' in contrast to 3 % using WHtR < 0·5. For hypertension, comparative values were 23 and 9 %, and for total/HDL-cholesterol > 4, 26 and 13 %. Nearly one-third of the 'no increased risk' group in the 'matrix' had WHtR ≥ 0·5 and hence could be underdiagnosed for cardiometabolic risk. WHtR has the potential to be a better indicator of cardiometabolic risks associated with central obesity than the current NICE 'matrix'. The cut-off WHtR 0·5 in early screening translates to a simple message, 'your waist should be less than half your height', that allows individuals to be aware of their health risks.