Table 3

The association between smoking status and PsA* (N=654) compared with psoriasis alone (N=401) by logistic regression analysis, adjusted for age, sex, level of education, alcohol consumption, duration and severity of psoriasis

Univariate modelMultivariate model
CovariateOR95% CIp ValueOR95% CIp Value
Smoking status
 Current vs life-time non- smokers0.660.48 to 0.900.0090.570.41 to 0.810.002
 Past vs life-time non- smokers0.630.46 to 0.840.0020.810.56 to 1.120.21
Age group, years
 31–400.420.28 to 0.62<0.00010.490.33 to 0.750.0009
 41–500.340.23 to 0.51<0.00010.430.28 to 0.65<0.0001
 51–600.140.09 to 0.22<0.00010.180.11 to 0.28<0.0001
 >600.100.06 to 0.17<0.00010.060.07 to 0.23<0.0001
Sex: male vs female0.910.71 to 1.170.471.030.78 to 1.360.85
Duration of psoriasis, years
 6–100.850.58 to 1.250.410.700.47 to 1.060.09
 11–150.660.43 to 1.020.060.490.31 to 0.790.003
 16–200.450.28 to 0.700.00050.460.28 to 0.740.002
 21 and more0.260.19 to 0.37<0.00010.370.26 to 0.53<0.0001
Alcohol consumption
 Social vs none0.920.69 to 1.220.550.940.68 to 1.280.67
 Daily vs none1.170.74 to 1.840.501.650.99 to 2.760.05
Severe psoriasis: yes vs no2.131.56 to 2.91<0.00012.071.47 to 2.92<0.0001
  • * Psoriatic arthritis (PsA) is the outcome variable.

  • Age at the time of the diagnosis for PsA and at first study visit for psoriasis. The reference group is 30 years and younger.

  • Duration of psoriasis at the time of the diagnosis of PsA (for PsA) and at first study visit (for psoriasis). The reference group is 5 years and less