| 
      
        |  | Untreated | Treated |  
        |  | Socioeconomic status |  | Socioeconomic status |  
        | All | Low | High | All | Low | High |  
        | n=767 | n=613 | n=164 | n=1666 | n=967 | n=699 |  
        | Age, mean | 52.2 years | 53.1years | 48.9years | 56.2years | 57.3years | 55.6years |  
        | Age 40-44 years | 23.6 | 20.9 | 33.5 | 7.2 | 4.8 | 10.6 |  
        | Age 45-49 years | 20.2 | 19.6 | 22.6 | 13.0 | 11.1 | 15.6 |  
        | Age 50-54 years | 20.2 | 19.1 | 24.4 | 20.5 | 19.6 | 21.6 |  
        | Age 55-59 years | 14.0 | 14.4 | 12.8 | 23.8 | 23.2 | 24.7 |  
        | Age 60-64 years | 10.7 | 12.2 | 4.9 | 20.9 | 23.2 | 17.7 |  
        | Age 65-69 years | 11.3 | 13.9 | 1.8 | 14.6 | 18.2 | 9.7 |  
        | Educational level (years) |  |  |  |  |  |  |  
        | Primary education    (0-9) | 25.2 | 32.0 | - | 21.9 | 37.7 | - |  
        | High school  (10-12) | 48.8 | 61.8 | - | 31.5 | 54.3 | - |  
        | University (13 +) | 24.7 | 4.6 | 100.0 | 46.6 | 8.0 | 100.0 |  
        | Income, NOK per year |  |  |  |  |  |  |  
        | 0-99999 | 16.0 | 18.9 | 4.9 | 4.3 | 6.7 | 0.9 |  
        | 100000-199999 | 29.0 | 34.6 | 7.9 | 17.4 | 26.5 | 4.9 |  
        | 200000-399999 | 50.8 | 44.4 | 75.0 | 60.1 | 60.5 | 59.5 |  
        | 400000-599999 | 3.6 | 2.0 | 9.8 | 15.2 | 5.7 | 28.5 |  
        | 600000-999999 | 0.6 | 0.2 | 2.4 | 2.6 | 0.4 | 5.7 |  
        | 1mill + |  | - | - | 0.4 | 0.2 | 0.6 |  
        | Works more than 10 hours a week | 73.1 | 65.9 | 100.0 | 83.9 | 72.2 | 100.0 |  
        | Has partner (married or cohabitant) | 77.9 | 79.1 | 73.2 | 79.9 | 79.2 | 80.8 |  
        | Is member of organizations | 57.9 | 54.5 | 70.7 | 68.3 | 65.3 | 72.5 |  
        | Geographical health region |  |  |  |  |  |  |  
        | North | 11.5 | 11.6 | 11.0 | 12.8 | 13.3 | 12.0 |  
        | Mid | 16.1 | 16.0 | 16.5 | 13.3 | 13.4 | 13.2 |  
        | West | 19.2 | 20.1 | 15.9 | 14.8 | 16.4 | 12.6 |  
        | South-East | 53.3 | 52.4 | 56.7 | 59.1 | 56.8 | 62.2 |  
        | Self-assessed health |  |  |  |  |  |  |  
        | Very    good | 34.1 | 30.0 | 49.4 | 17.8 | 14.7 | 22.2 |  
        | Good | 42.9 | 43.9 | 39.0 | 43.3 | 43.6 | 42.8 |  
        | Neither good nor poor | 16.5 | 18.3 | 9.8 | 30.0 | 31.9 | 27.3 |  
        | Poor | 6.2 | 7.5 | 1.2 | 8.5 | 9.2 | 7.4 |  
        | Very poor | 0.4 | 0.3 | 0.6 | 0.5 | 0.6 | 0.3 |  |