Final multiple regression model for New Zealand score in knees (n = 201, R2 = 0.37a).
| Variableb | Category/scale | Number in category | Adjusted difference in means | 95% CI | P-value |
| Employment status | 0.049 | ||||
| Paid employment (reference) | 65 | 0 | |||
| No paid employment | 10 | 1.7 | −6.8 to 10.1 | ||
| Sick/disabled | 8 | 8.5 | −3.1 to 20.1 | ||
| Retired | 118 | 6.1 | 0.9 to 11.3 | ||
| Social class | 0.0055 | ||||
| I (reference) | 11 | 0 | |||
| II | 70 | 5.1 | −3.4 to 13.6 | ||
| IIINM | 33 | −4.6 | −14.5 to 5.2 | ||
| IIIM | 44 | 3.5 | −5.7 to 12.6 | ||
| IV | 29 | 4.2 | −6.2 to 14.6 | ||
| V | 14 | 8.3 | −1.8 to 18.3 | ||
| Body mass index (kg/m2) | 0.47c | 0.01 to 0.94 | 0.047 | ||
| Hypertension | 0.041 | ||||
| No (reference) | 157 | 0 | |||
| Yes | 44 | 5.5 | 0.2 to 10.8 | ||
| ‘Other health problems’d | 0.038 | ||||
| No (reference) | 93 | 0 | |||
| Yes | 108 | 4.6 | 0.3 to 8.8 |
↵a 0.25 of this is attributable to baseline, sex and age.
↵b Adjusted as before for the sampling design (stratification by sex and age; clustering by general practice) as well as all the other factors.
↵c The regression coefficient is the adjusted difference in New Zealand score for a unit increase in body mass index (mean = 27.5, standard deviation = 4.6, range = 18.0 to 49.3 kg/m2).
↵d Other than those specified in the list given in the methods section.