Table 5.
Mean difference and SD of the difference, LOA, sensitivities, specificities and Youden index in predicting BMI, excess weight and obesity from regression models developed to predict measured height/weight from self-reported height/weight (split-sample B)
| Model* | BMI | Excess weight (BMI ≥25 kg/m2) | Obesity (BMI ≥30 kg/m2) | |||||||
| Mean difference (SD) | LOA | Cc. | Sens. | Spec. | Youden Index | Cc. | Sens. | Spec. | Youden Index | |
| % | % | % | % | % | % | % | % | |||
| Men (n=5297) | ||||||||||
| BMI from height and weight | ||||||||||
| Self-report alone | −0.96 (1.47) | −4.1, 2.1 | 88.1 | 85.0 | 94.4 | 79.3 | 91.9 | 70.6 | 98.9 | 69.5 |
| Mean correction | −0.36 (1.47) | −3.5, 2.7 | 90.1 | 91.5 | 87.3 | 78.8 | 93.2 | 79.3 | 97.8 | 77.0 |
| Equation 1 | 0.00 (1.45) | −3.1, 3.0 | 90.3 | 93.7 | 83.6 | 77.2 | 93.2 | 85.0 | 96.0 | 81.0 |
| Equation 2 | 0.00 (1.42) | −3.0, 3.0 | 90.8 | 94.0 | 84.6 | 78.6 | 93.7 | 85.7 | 96.4 | 82.0 |
| Equation 3 | 0.00 (1.41) | −3.0, 3.0 | 90.9 | 93.9 | 85.1 | 79.0 | 93.6 | 85.6 | 96.4 | 82.0 |
| Equation 4 | −0.01 (1.41) | −3.0, 2.9 | 91.0 | 94.1 | 84.9 | 79.0 | 93.7 | 85.4 | 96.4 | 81.8 |
| Model using continuous age | 0.03 (1.41) | −2.9, 3.0 | 91.0 | 94.2 | 84.7 | 78.9 | 93.5 | 85.6 | 96.2 | 81.8 |
| Women (n=6145) | ||||||||||
| BMI from height and weight | ||||||||||
| Self-report alone | −1.04 (1.65) | −4.2, 2.1 | 89.3 | 82.5 | 97.7 | 80.2 | 93.2 | 74.7 | 98.9 | 73.6 |
| Mean correction | −0.12 (1.66) | −3.3, 3.0 | 91.5 | 92.0 | 90.8 | 82.8 | 94.3 | 83.9 | 97.6 | 81.5 |
| Equation 1 | 0.02 (1.62) | −3.1, 3.1 | 91.4 | 93.5 | 88.8 | 82.3 | 94.3 | 86.1 | 96.9 | 83.0 |
| Equation 2 | 0.02 (1.60) | −3.0, 3.1 | 91.7 | 93.1 | 89.9 | 83.0 | 94.3 | 86.4 | 96.8 | 83.2 |
| Equation 3 | 0.02 (1.59) | −3.0, 3.1 | 91.8 | 93.0 | 90.4 | 83.4 | 94.5 | 86.9 | 97.0 | 83.8 |
| Equation 4 | 0.02 (1.59) | −3.0, 3.1 | 91.8 | 93.1 | 90.3 | 83.4 | 94.5 | 86.7 | 97.0 | 83.7 |
| Model using continuous age | 0.02 (1.60) | −3.0, 3.1 | 91.8 | 93.1 | 90.2 | 83.3 | 94.3 | 86.2 | 96.8 | 83.0 |
*BMI derived from predicted values of height and weight. Mean-correction equation (derived from the full models for an all mean/reference individual: see online supplemental tables S5–S6. Equation 1: Measured height/weight predicted from self-reported height/weight alone (including any non-linear terms). Equation 2: Measured height/weight predicted from self-reported height/weight, categorical age (reduced model). Equation 3: Measured height/weight predicted from self-reported height/weight, categorical age, other variables associated with misreporting (full model). Equation 4: Measured height/weight predicted from self-reported height/weight, categorical age, other variables, self-reported BMI. LOA estimated using unweighted data.
BMI, body mass index; Cc, correctly classified; LOA, limits of agreement; Sens, sensitivity; Spec, specificity.