Table 2. Age- and multivariate-adjusted RRs for the association of smoking status with risk of psoriatic arthritis (PsA) among all participants*.
| Cases | Person- years |
Age-adjusted RR (95% CI) |
Multivariate- adjusted RR # (95% CI) |
|
|---|---|---|---|---|
| Reference: Never smokers | 76 | 865,189 | 1.00 | 1.00 |
| Smoking status | ||||
| Past smokers | 46 | 309,749 | 1.55 (1.07-2.23) | 1.54 (1.06-2.24) |
| Current smokers | 35 | 129,032 | 3.08 (2.06-4.61) | 3.12 (2.07-4.69) |
| 1-14 cigarettes/day | 12 | 62,479 | 2.19 (1.19-4.02) | 2.34 (1.27-4.33) |
| ≥15 cigarettes/day | 23 | 66,553 | 3.92 (2.45-6.27) | 3.77 (2.35-6.06) |
| P for trend | <0.0001 | <0.0001 | ||
| Duration | ||||
| Duration, <25 years | 55 | 366,471 | 1.68 (1.19-2.38) | 1.70 (1.19-2.42) |
| Duration, ≥25 years | 26 | 72,310 | 3.20 (2.02-5.07) | 3.12 (1.96-4.97) |
| P for trend | <0.0001 | <0.0001 | ||
| Pack-years | ||||
| pack-years, <20 | 44 | 342,974 | 1.43 (0.99-2.08) | 1.48 (1.02-2.16) |
| pack-years, 20-44 | 34 | 91,129 | 3.67 (2.42-5.56) | 3.33 (2.19-5.06) |
| pack-years, ≥45 | 3 | 4,678 | 4.53 (1.41-14.56) | 3.91 (1.21-12.59) |
| P for trend | <0.0001 | <0.0001 |
*
Psoriasis cases with only skin phenotypes were excluded during the follow-up.
#
Adjusted for age (continuous variable), body mass index (<18.5, 18.5-24.9, 25-29.9, 30-34.9 or ≥35 kg/m2), alcohol drinking (no, <4.9, 5.0-9.9, 10-14.9, 15-29.9 or ≥30.0 g/d), vigorous physical activity (metabolic equivalent hours/wk, in quintile).