Table 1 Characteristics of the prospective cohort (n = 341)
Variable | Total (n) | Frequency (%) | Mean (95% CI) |
|---|---|---|---|
Sex | 341 | . | . |
   Women | . | 153 (44.9%) | . |
   Men | . | 188 (55.1%) | . |
Age (in years) | 341 | . | 52.35 (51.84-52.86) |
Occupation (SES) | 337 | . | . |
   Non manual | . | 185 (54.9%) | . |
   Manual | . | 112 (33.2%) | . |
   Self-employed | . | 40 (11.9%) | . |
Smoking, current | 332 | 69 (20.8%) | . |
BMI (kg/m2) | 340 | . | 26.11 (25.70-26.52) |
Alcohol consumption | 325 | . | . |
   Lowa | . | 264 (81.2%) | . |
   Mediumb | . | 36 (11.1%) | . |
   Highc | . | 25 (7.7%) | . |
Disease (self report of diagnosis) | 341 | 171 (50.2%) | . |
Previous back pain | 330 | 219 (66.4%) | . |
"Poor" work ability | 278 | 56 (20.1%) | . |
Sickness absence spells at baseline†| 341 | . | 0.47 (0.39-0.55) |
Sickness absence spells at follow-up‡ | 340 | . | 0.49 (0.42-0.56) |
Sickness absence days at baseline†| 335 | . | 6.59 (4.83-8.35) |
Sickness absence days at follow-up‡ | 340 | . | 6.96 (5.09-8.83) |