Table 2.
Univariable stratified analysis exploring determinants of employment in subjects aged≤65 years
| Variable | Controls (n=465) | AS—low education (n=145) | AS—high education (n=69) | ||||||
| IRR | CI | P values | IRR | CI | P values | IRR | CI | P values | |
| Age, years | 0.99 | 0.99 to 1.00 | <0.01 | 0.98 | 0.97 to 0.99 | <0.01 | 0.99 | 0.98 to 1.01 | 0.24 |
| Gender, male | 1.11 | 1.01 to 1.23 | 0.03 | 1.40 | 1.04 to 1.88 | 0.03 | 0.98 | 0.73 to 1.30 | 0.87 |
| Education, high | 1.13 | 1.04 to 1.23 | <0.01 | – | – | * | – | – | * |
| Smoking, current | 0.95 | 0.85 to 1.06 | 0.35 | 0.84 | 0.59 to 1.19 | 0.33 | 1.06 | 0.72 to 1.56 | 0.76 |
| Alcohol use, yes | 1.13 | 0.99 to 1.29 | 0.06 | 1.33 | 0.91 to 1.94 | 0.14 | 2.14 | 1.06 to 4.32 | 0.03 |
| BMI, kg/m2 | 1.00 | 1.00 to 1.01 | 0.35 | 0.99 | 0.96 to 1.02 | 0.57 | 0.98 | 0.94 to 1.02 | 0.28 |
| Comorbidity (SCQ, 0–39) | 0.94 | 0.90 to 0.97 | <0.01 | 0.94 | 0.89 to 0.98 | <0.01 | 0.95 | 0.89 to 1.00 | 0.06 |
| SF-36 PCS (0–100) | 1.01 | 1.01 to 1.02 | <0.01 | 1.03 | 1.02 to 1.04 | <0.01 | 1.01 | 1.00 to 1.03 | 0.06 |
| SF-36 MCS (0–100) | 1.01 | 1.00 to 1.01 | 0.03 | 1.00 | 0.99 to 1.02 | 0.42 | 1.00 | 0.99 to 1.01 | 0.84 |
| Mastery (7-28) | 1.02 | 1.01 to 1.03 | <0.01 | 1.07 | 1.04 to 1.10 | <0.01 | 1.02 | 0.98 to 1.06 | 0.26 |
* Education not included in model, as AS population was stratified by level of education.
AS, ankylosing spondylitis; BMI, body mass index; IRR, incidence rate ratio; SCQ, Self-Administered Comorbidity Questionnaire; SF-36 PCS, Short-Form 36 Physical Component Summary; SF-36 MCS, Short-Form 36 Mental Component Summary.