Table 2.
Relative Risks of Lung Cancer by Number of Years Working Rotating Night Shifts Stratified by Smoking Status Among 78,612 Women in the Nurses' Health Study, 1988–2008
| Time Working Rotating Night Shifts, years | All Women |
Never Smokers |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | RRa | 95% CI | RRb | 95% CI | RRc | 95% CI | No. | RRa | 95% CI | RRd | 95% CI | |
| 0 | 542 | 1.00 | Referent | 1.00 | Referent | 1.00 | Referent | 52 | 1.00 | Referent | 1.00 | Referent |
| 1–5 | 572 | 1.03 | 0.91, 1.16 | 1.02 | 0.90, 1.14 | 1.03 | 0.91, 1.16 | 63 | 1.22 | 0.84, 1.77 | 1.19 | 0.82, 1.73 |
| 6–14 | 177 | 1.09 | 0.92, 1.29 | 0.95 | 0.80, 1.13 | 0.96 | 0.81, 1.14 | 11 | 0.79 | 0.41, 1.51 | 0.75 | 0.39, 1.45 |
| ≥15 | 164 | 1.44 | 1.21, 1.72 | 1.23 | 1.03, 1.47 | 1.28 | 1.07, 1.53 | 11 | 1.06 | 0.55, 2.05 | 1.00 | 0.51, 1.94 |
| P for trend | <.0001 | 0.07 | 0.03 | 0.78 | 0.65 | |||||||
| Former Smokers |
Current Smokers |
|||||||||||
| No. | RRa | 95% CI | RRe | 95% CI | No. | RRa | 95% CI | RRf | 95% CI | |||
| 0 | 289 | 1.00 | Referent | 1.00 | Referent | 191 | 1.00 | Referent | 1.00 | Referent | ||
| 1–5 | 292 | 0.96 | 0.81, 1.13 | 0.99 | 0.83, 1.16 | 203 | 0.99 | 0.81, 1.22 | 1.01 | 0.82, 1.24 | ||
| 6–14 | 78 | 0.89 | 0.69, 1.14 | 0.86 | 0.66, 1.10 | 84 | 1.12 | 0.86, 1.46 | 1.16 | 0.89, 1.52 | ||
| ≥15 | 68 | 1.15 | 0.88, 1.51 | 1.06 | 0.81, 1.38 | 80 | 1.53 | 1.17, 2.01 | 1.61 | 1.21, 2.13 | ||
| P for trend | 0.52 | 0.92 | 0.001 | 0.0006 | ||||||||
Abbreviation: CI, confidence interval; RR, relative risk.
a Adjusted for age (continuous) and time period.
b Adjusted for age (continuous), time period, smoking status (never, past, or current), cigarettes smoked per day among current smokers (1–4, 5–14, 15–24, 25–34, 35–44, and ≥45 cigarettes/day), and time since quitting among past smokers (<3, 3–5, 6–9, 10–14, 15–19, and ≥20 years ago).
c Adjusted for age (continuous), smoking status (never, past, or current), age at start of smoking (continuous), cigarettes smoked per day among current smokers (1–4, 5–14, 15–24, 25–34, 35–44, and ≥45 cigarettes/day), time since quitting among past smokers (<3, 3–5, 6–9, 10–14, 15–19, and ≥20 years ago), fruit intake (<1.5, 1.5–1.99, 2.0–2.49, 2.5–2.99, and ≥3.0 servings/day), vegetable intake (<2.0, 2.0–2.49, 2.5–2.99, 3.0–3.99, and ≥4.0 servings/week), and body mass index, measured as weight in kilograms divided by height in meters squared (<20, 20–21.9, 22–23.9, 24–26.9, 27–29.9, and >30), as well as environmental smoking exposures: parents smoking while living with them (no, mother only, father only, or both parents), years living with someone who smoked (<1, 1–9, 10–19, 20–29, and ≥30 years), exposure to smoking at work (no, occasionally, and regularly), and exposure to smoking at home (no, occasionally, and regularly).
d Adjusted for age (continuous), fruit intake (<1.5, 1.5–1.99, 2.0–2.49, 2.5–2.99, and ≥3.0 servings/day), vegetable intake (<2.0, 2.0–2.49, 2.5–2.99, 3.0–3.99, and ≥4.0 servings/week), and body mass index, measured as weight in kilograms divided by height in meters squared (<20, 20–21.9, 22–23.9, 24–26.9, 27–29.9, and >30), as well as environmental smoking exposures: parents smoking while living with them (no, mother only, father only, or both parents), years living with someone who smoked (<1, 1–9, 10–19, 20–29, and ≥30 years), exposure to smoking at work (no, occasionally, and regularly), and exposure to smoking at home (no, occasionally, and regularly).
e Adjusted for age (continuous), age at start of smoking (continuous), time since quitting (<3, 3–5, 6–9, 10–14, 15–19, and ≥20 years ago), fruit intake (<1.5, 1.5–1.99, 2.0–2.49, 2.5–2.99, and ≥3.0 servings/day), vegetable intake (<2.0, 2.0–2.49, 2.5–2.99, 3.0–3.99, and ≥4.0 servings/week), body mass index, measured as weight in kilograms divided by height in meters squared (<20, 20–21.9, 22–23.9, 24–26.9, 27–29.9, and >30), menopausal status (premenopausal vs. postmenopausal), hormone use among postmenopausal women (never, past, and current user), oral contraceptive use (never, <5 years, and ≥5 years), as well as environmental smoking exposures: parents smoking while living with them (no, mother only, father only, or both parents), years living with someone who smoked (<1, 1–9, 10–19, 20–29, and ≥30 years), exposure to smoking at work (no, occasionally, and regularly), and exposure to smoking at home (no, occasionally, and regularly).
f Adjusted for age (continuous), age at start smoking (continuous), cigarettes smoked per day (1–4, 5–14, 15–24, 25–34, 35–44, and ≥45 cigarettes/day), fruit intake (<1.5, 1.5–1.99, 2.0–2.49, 2.5–2.99, and ≥3.0 servings/day), vegetable intake (<2.0, 2.0–2.49, 2.5–2.99, 3.0–3.99, and ≥4.0 servings/week), body mass index, measured as weight in kilograms divided by height in meters squared (<20, 20–21.9, 22–23.9, 24–26.9, 27–29.9, and >30), menopausal status (premenopausal vs. postmenopausal), hormone use among postmenopausal women (never, past, and current user), and oral contraceptive use (never, <5 years, and ≥5 years), as well as environmental smoking exposures: parents smoking while living with them (no, mother only, father only, or both parents), years living with someone who smoked (<1, 1–9, 10–19, 20–29, and ≥30 years), exposure to smoking at work (no, occasionally, and regularly), and exposure to smoking at home (no, occasionally, and regularly).