Table 1

Classification of risk category in all participants by the ‘matrix’, based on BMI and waist circumference, by WHtR, and by both

‘Matrix’ classificationBase (n)WHtR <0.5 as % of those in ‘matrix’ category (n)WHtR ≥0.5 and <0.6 as % in ‘matrix’ category (n)WHtR ≥0.6 as % in ‘matrix’ category (n)
NA (underweight)17100% (17)00
‘no increased risk’57665% (367)35% (209)0
‘increased’ and ‘high’ risk4703% (15)78% (366)19% (89)
‘very high risk’390018% (68)82% 322)
Total participants145329% (399)44% (643)27% (411)
  • The numbers of participants in column b are actual base numbers (unweighted). Percentages are calculated using weighted data.

  • The ‘matrix’ of waist circumference × BMI classified health risk as: ‘not applicable’/underweight, ‘no increased risk’, ‘increased risk’,’ high risk’ and ‘very high risk’. The ‘matrix’ only classifies those with a combination of high waist circumference and overweight by BMI as being at ‘increased’ risk.

  • We combined the ‘matrix’ categories of ‘increased risk’ and ‘high risk’ to obtain three groups with similar numbers of adults, for comparison with our three categories of WHtR.

  • Categories for waist circumference within the ‘matrix’ were: low (men: <94 cm, women: <80 cm), high (men: 94–102 cm women: 80–88 cm); very high (men: >102 cm, women: >88 cm).

  • Categories for BMI within the ‘matrix’ were: underweight (<18.5 kg/m2); healthy weight (18.5–24.9 kg/m2); overweight (25–29.9 kg/m2); obese (30–39.9 kg/m2); very obese (>40 kg/m2).

  • Categories for WHtR were: ‘no increased risk’ (WHtR <0.5),’ increased risk’ (WHtR 0.5 to <0.6) and ‘very high risk’ (WHtR 0.6+).

  • Columns c, d and e refer to participants in the survey who had WHtR <0.5, ≥0.5, but <0.6, and ≥0.6, expressed as a percentage of the total in each ‘matrix’ category.

  • BMI, body mass index; NA, not applicable; WHtR, waist-to-height ratio.