Risk of basal cell carcinoma by rotating night shift work 2001–2011 stratified by hair colour among women in Nurses' Health Study II
| Hair colour | Person-years | Number of case participants | Multivariable Model HR (95% CI)* |
|---|---|---|---|
| Red/blonde | |||
| Years on rotating night shift | |||
| Never | 34 071 | 315 | 1.00 (referent) |
| <2 | 34 138 | 285 | 0.89 (0.75 to 1.05) |
| 2–5.9 | 29 696 | 257 | 0.99 (0.83 to 1.17) |
| 6–9.9 | 14 116 | 119 | 0.95 (0.76 to 1.18) |
| ≥10 | 10 366 | 92 | 0.94 (0.74 to 1.20) |
| Per 5 years | 1.00 (0.92 to 1.08) | ||
| Brown/black | |||
| Years on rotating night shift | |||
| Never | 140 172 | 962 | 1.00 (referent) |
| <2 | 135 674 | 883 | 0.95 (0.87 to 1.04) |
| 2–5.9 | 115 910 | 730 | 0.95 (0.86 to 1.05) |
| 6–9.9 | 52 586 | 273 | 0.80 (0.70 to 0.92) |
| ≥10 | 42 369 | 220 | 0.80 (0.69 to 0.92) |
| Per 5 years | 0.91 (0.87 to 0.96) | ||
*Covariates included in the multivariable model: years of shift work (≤2, 2–5.9, 6–9.9, ≥10), hours of sleep per night (≤6, 7, 8, ≥9), sleep adequacy (yes/no), sleepy days per week (none, 1–3, 4–6, 7), snoring (never, occasionally, few, most, every night per week), restless legs syndrome (yes/no), family history of melanoma (yes/no), hours spent in sun per week ages 25–35 (< 1, 2–4, ≥5), number of severe sunburns from ages 15 to 20 (none, 1, 2, 3–4, 5–9, ≥10), sunburn severity after ≥2 hours in the sun during childhood (no reaction, some redness, burn, painful burn/blisters), artificial tanning frequency per year ages 25–35 (never, 1–2, 3–5, 6–11, ≥12 per year), annual UV at residence (<104, 104–112, 113–119, 120–144, ≥145 R-B units), moles on lower legs (1–2, 3–4, 5–9, 10–14, 15–20, ≥21), marital status (single, married, divorced/separated/widow), financial status on 10-rung ladder (top rungs 9–10, rungs 7–8, rungs 5–6, bottom rungs 1–4), body mass index, kg/m2 (BMI; <22, 22–24.9, 25–28.9, ≥29), physical activity (metabolic equivalents from recreational and leisure-time activities (MET) hours/week: <3, 3–8.9, 9–17.9, 18–26.9, 27–41.9, ≥42), smoking status (never, past, current), menopausal status (premenopausal, postmenopausal, dubious menopause), postmenopausal hormones (no use, past use, current use), oral contraceptive use (never, <4 years, 4 to < 8 years, ≥8 years), g/day alcohol intake (none, > 0 to < 5; 5 to < 10, ≥10); Alternate Healthy Eating Index (0–29, 30–39, 40–49, 50–59, 60–100).