Table 2. Risk factors in relation to mental wellbeing (WEMWBS): differences in mean, variability and skewness estimated by GAMLSS (n = 7,104).
| Risk factor | % | NO distribution | BCCG distribution | |||
|---|---|---|---|---|---|---|
| Mean | SD | Median | COV | Skewness* | ||
| Female (ref) | 52.8% | 49.2 | 8.5 | 50 | 0.17 | –0.41 |
| Male | 47.2% | 49.1 | 8.2 | 50 | 0.17 | –0.40 |
| Unadjusted difference, % (SE) | –0.2 (0.4) | –3.9 (1.7) | –0.3 (0.4) | –3.5 (1.7) | 0.02 (0.11) | |
| Adjusted† difference, % (SE) | –0.6 (0.4) | –3.6 (1.7) | –0.7 (0.4) | –2.6 (1.7) | 0.00 (0.11) | |
| Non-manual (ref) | 34.8% | 50.1 | 7.9 | 51 | 0.16 | –0.45 |
| Manual social class | 65.2% | 48.7 | 8.5 | 49 | 0.17 | –0.37 |
| Unadjusted difference, % (SE) | –2.8 (0.4) | 7.2 (1.8) | –2.9 (0.4) | 10.9 (1.8) | –0.20 (0.12) | |
| Adjusted† difference, % (SE) | –2.5 (0.4) | 6.0 (1.8) | –2.7 (0.4) | 9.8 (1.8) | –0.24 (0.12) | |
| Physically active (ref) | 72.4% | 49.9 | 8.0 | 51 | 0.16 | –0.38 |
| Inactive | 27.6% | 47.3 | 8.9 | 48 | 0.19 | –0.36 |
| Unadjusted difference, % (SE) | –5.3 (0.5) | 10.9 (1.9) | –5.2 (0.4) | 16.2 (1.9) | –0.12 (0.12) | |
| Adjusted† difference, % (SE) | –5.3 (0.5) | 9.9 (1.9) | –5.1 (0.4) | 15.2 (1.9) | –0.10 (0.12) | |
*
Skewness is estimated as the Box-Cox power (that is, the power required to transform the outcome to a normal distribution); differences are the absolute difference in Box-Cox power in each subgroup estimated by GAMLSS. GAMLSS estimates multiple distribution moments simultaneously; thus, differences may not exactly correspond to descriptive comparisons reported above.
†
Estimates mutually adjusted for sex, social class and physical inactivity.
NO: normal distribution; BCCG: Box-Cox Cole and Green distribution: SD: standard deviation; CoV: coefficient of variation; GAMLSS: Generalized Additive Models for Location, Scale and Shape; SE, standard error.