Table 2.
Relative risk of psoriasis by baseline status of working rotating night shifts: Nurses’ Health Study (1988–2008) and Nurses’ Health Study II (1989–2005)
| Cases | Person-years | Age-adjusted HR (95% CI) | Multivariate-adjusted HR 1 (95% CI) | |
|---|---|---|---|---|
| Nurses’ Health Study | 743 | 1,237,934 | ||
| Never | 258 | 510,681 | 1.00 | 1.00 |
| Ever | 485 | 727,253 | 1.32 (1.13–1.53) | 1.26 (1.09–1.47) |
| 1–2 years | 193 | 307,126 | 1.24 (1.03–1.50) | 1.24 (1.03–1.49) |
| 3–9 years | 195 | 285,560 | 1.35 (1.12–1.62) | 1.28 (1.07–1.55) |
| ≥10 years | 97 | 134,567 | 1.41 (1.12–1.79) | 1.29 (1.02–1.64) |
| P for trend | 0.0009 | 0.01 | ||
| Nurses’ Health Study II | 1,144 | 1,483,567 | ||
| Never | 397 | 569,814 | 1.00 | 1.00 |
| Ever | 747 | 913,753 | 1.17 (1.04–1.32) | 1.14 (1.01–1.28) |
| 1–2 years | 357 | 432,809 | 1.18 (1.02–1.36) | 1.18 (1.02–1.36) |
| 3–9 years | 328 | 414,435 | 1.14 (0.98–1.32) | 1.09 (0.94–1.26) |
| ≥10 years | 62 | 66,509 | 1.30 (0.99–1.70) | 1.14 (0.87–1.50) |
| P for trend | 0.067 | 0.42 | ||
| Nurses’ Health Study/Nurses’ Health Study II | ||||
| Never | 655 | 1,080,495 | 1.00 | 1.00 |
| Ever | 1,232 | 1,641,006 | 1.23 (1.10–1.38) | 1.19 (1.07–1.32) |
| 1–2 years | 550 | 739,935 | 1.20 (1.07–1.35) | 1.20 (1.07–1.34) |
| 3–9 years | 523 | 699,995 | 1.23 (1.04–1.45) | 1.17 (1.00–1.38) |
| ≥10 years | 159 | 201,076 | 1.29 (1.08–1.53) | 1.23 (1.03–1.47) |
| P for trend | 0.001 | 0.049 | ||
Abbreviations: CI, confidence interval; HR, Hazard ratio.
1
Adjusted for age (in continuous variable), body mass index (<21, 21–22.9, 23–24.9, 25–26.9, 27.0–29.9, 30.0–32.9, 33–34.9, ≥35 kg/m2), smoking (never, past, current with 1–14, 15–24, ≥25 cigs/day), alcohol intake (no, <4.9, 5.0–9.9, or ≥10.0 g/d), and physical activity (<3, 3.0–8.9, 9.0–17.9, 18.0–26.9 or ≥27.0 metabolic equivalent hours/wk). The covariates were time varying and updated in the analysis.