Classification of risk category in all participants by the ‘matrix’, based on BMI and waist circumference, by WHtR, and by both
| a | b | c | d | e |
|---|---|---|---|---|
| ‘Matrix’ classification | Base (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) | 17 | 100% (17) | 0 | 0 |
| ‘no increased risk’ | 576 | 65% (367) | 35% (209) | 0 |
| ‘increased’ and ‘high’ risk | 470 | 3% (15) | 78% (366) | 19% (89) |
| ‘very high risk’ | 390 | 0 | 18% (68) | 82% 322) |
| Total participants | 1453 | 29% (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.