Table 2.
Cigarette smoking in relation to incidence of lung cancer among 56,835 women in the Black Women’s Health Study, 1995–2011a
| No. of Cases | Person-years | Age-adjusted | Multivariableb | |||
|---|---|---|---|---|---|---|
| HR | (95% CI) | HR | (95% CI) | |||
| Never smoker | 46 | 504,685 | 1.00 | 1.00 | ||
| Smoking status | ||||||
| Former smoker | 140 | 175,421 | 4.68 | (3.34–6.56) | 2.40 | (1.57–3.68) |
| Current smoker | 137 | 109,004 | 11.94 | (8.53–16.71) | 4.42 | (2.79–6.99) |
| Pack-years | ||||||
| <10 | 43 | 138,675 | 2.91 | (1.92–4.42) | 2.77 | (1.82–4.22) |
| 10–19 | 70 | 69,595 | 7.01 | (4.79–10.25) | 6.35 | (4.32–9.35) |
| 20–29 | 34 | 28,928 | 8.24 | (5.24–12.95) | 7.50 | (4.76–11.84) |
| 30–39 | 62 | 19,346 | 14.86 | (9.99–22.11) | 13.19 | (8.81–19.74) |
| 40+ | 52 | 12,586 | 18.95 | (12.54–28.62) | 16.92 | (11.13–25.71) |
| p for trend | <0.01 | <0.01 | ||||
| Cigarettes per day | ||||||
| <5 | 36 | 83,408 | 3.48 | (2.24–5.40) | 3.27 | (2.10–5.09) |
| 5–14 | 108 | 115,373 | 7.02 | (4.95–9.96) | 6.30 | (4.42–8.99) |
| 15–24 | 86 | 58,373 | 9.21 | (6.40–13.26) | 8.29 | (5.73–11.99) |
| 25+ | 44 | 21,927 | 11.22 | (7.36–17.08) | 10.14 | (6.63–15.51) |
| p for trend | <0.01 | <0.01 | ||||
| Age started smoking | ||||||
| <16 | 79 | 51,889 | 14.20 | (9.85–20.47) | 5.09 | (3.15–8.25) |
| 16–17 | 65 | 56,260 | 8.95 | (6.12–13.09) | 3.66 | (2.26–5.92) |
| 18–19 | 65 | 73,491 | 5.80 | (3.96–8.49) | 2.78 | (1.74–4.45) |
| 20+ | 62 | 90,301 | 3.92 | (2.66–5.76) | 2.06 | (1.30–3.28) |
| p for trend | <0.01 | 0.10 | ||||
a
Abbreviations: HR=Hazard Ratio, CI=Confidence Interval
b
Adjusted for age, education, physical activity, alcohol consumption, parity, age at first birth, family history of lung cancer, and geographic region. Models for smoking status and age started smoking were additionally adjusted for pack-years of smoking.