Cross-tabulation of measured and self-reported BMI categories by sex
| Self-reported BMI categories | Measured BMI categories | ||||
| Under-weight | Normal | Overweight but not obese | Obese I & II | Obese III | |
| n (%) | n (%) | n (%) | n (%) | n (%) | |
| Men (n=17 868) | |||||
| Underweight | 209 (69.2) | 167 (2.7) | 4 (0.0) | 2 (0.0) | 0 (0.0) |
| Normal | 91 (30.1) | 5704 (91.0) | 1927 (23.5) | 49 (1.1) | 0 (0.0) |
| Overweight but not obese | 2 (0.7) | 390 (6.2) | 6081 (74.2) | 1475 (32.0) | 5 (1.4) |
| Obese I and II | 0 (0.0) | 7 (0.1) | 184 (2.2) | 3051 (66.2) | 178 (50.9) |
| Obese III | 0 (0.0) | 1 (0.0) | 1 (0.0) | 32 (0.7) | 166 (47.6) |
| Sensitivity | 69% | 91% | 74% | 66% | 48% |
| Specificity | 99% | 85% | 84% | 98% | 100% |
| Youden Index | 68% | 76% | 58% | 64% | 47% |
| κ | 0.66 | ||||
| Women (n=21 072) | |||||
| Underweight | 303 (73.7) | 292 (3.6) | 8 (0.1) | 0 (0.0) | 0 (0.0) |
| Normal | 106 (25.8) | 7524 (93.5) | 1886 (30.3) | 79 (1.9) | 5 (0.7) |
| Overweight but not obese | 2 (0.5) | 223 (2.8) | 4176 (67.1) | 1244 (29.9) | 10 (1.5) |
| Obese I and II | 0 (0.0) | 7 (0.1) | 152 (2.4) | 2796 (67.1) | 272 (43.3) |
| Obese III | 0 (0.0) | 1 (0.0) | 2 (0.0) | 47 (1.1) | 342 (54.5) |
| Sensitivity | 74% | 93% | 67% | 67% | 54% |
| Specificity | 98% | 82% | 89% | 97% | 100% |
| Youden Index | 72% | 75% | 56% | 64% | 54% |
| κ | 0.67 | ||||
κ (Cohen’s kappa statistic). Participants with valid self-reported and measured height and weight (n=38 940). Cell counts are weighted (rounded); estimates are column percentages. Shaded cells indicate those who were classified in the same category of BMI based on self-reported and measured height and weight. Underweight (<18.5 kg/m2); normal (≥18.5–24.9 kg/m2); overweight but not obese (≥25.0–29.9 kg/m2); obese I and II (≥30.0–39.9 kg/m2); obese III (≥40.0 kg/m2).
BMI, body mass index.