Lung cancer risk in current smokers in relation to smoking duration, cpd, and age at onset of smoking habit
United States | Japan | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Cases | Hospital Controls | OR (95% CI) | Cases | Hospital Controls | Community Controls | OR (95% CI) (HC; CC)a | ||||||
n | 148 | 39 | 284 | 115 | 160 | |||||||
Smoking duration (yr) % | ||||||||||||
≤40 | 38.5 | 56.4 | 25.2 (11.9–61.0)b | 40.5 | 71.3 | 45.0 | 2.2 (1.1–5.2); 4.8 (2.6–8.9)c | |||||
>40 | 61.5 | 43.6 | 57.8 (27.4–131.9)b | 59.5 | 28.7 | 55.0 | 7.4 (2.9–19.4); 8.3 (4.5–15.4)c | |||||
Mean (SD) | 42.6 (10.8) | 38.7 (12.3) | 41.6 (9.8) | 35.4 (9.8) | 40.6 (10.3) | |||||||
cpd % | ||||||||||||
<20 | 10.8 | 38.5 | 10.9 (4.4–28.0)b | 16.8 | 29.8 | 30.6 | 1.6 (0.7–3.9); 2.6 (1.4–4.9)c | |||||
20–29 | 35.1 | 28.2 | 53.4 (23.1–135.2)b | 35.0 | 34.2 | 41.3 | 3.5 (1.5–8.4); 4.3 (2.4–7.6)c | |||||
≥30 | 54.1 | 33.3 | 73.3 (32.5–181.6)b | 48.2 | 36.0 | 28.1 | 6.2 (2.6–15.0); 9.3 (5.2–16.7)c,d | |||||
Mean (SD) | 30.6 (15.5) | 22.9 (16.4) | 29.5 (15) | 25 (14.8) | 22.7 (12.8) | |||||||
Age at onset of smoking (yr) % | ||||||||||||
<14 | 30.4 | 20.5 | 1.2 (0.4–3.4)e | 0.7 | 0.0 | 0.0 | (f) | |||||
15–17 | 38.5 | 33.3 | 1 (reference)e | 21.1 | 11.3 | 15.6 | 1 (reference)g | |||||
18–20 | 18.2 | 25.6 | 0.6 (0.2–1.7)e | 61.6 | 68.7 | 60.0 | 0.2 (0.1–0.6); 0.8 (0.5–1.3)g | |||||
>20 | 12.8 | 20.5 | 0.5 (0.2–1.4)e | 16.6 | 20.0 | 24.4 | 0.2 (0.1–0.8); 0.5 (0.3–0.9)g,h | |||||
Mean (SD) | 16.8 (5.8) | 17.8 (5.0) | 19.3 (2.9) | 20.2 (4.7) | 20.5 (5.8) |
a HC, hospital controls; CC, community controls.
b Adjusted for age, education, and hospital; reference group is nonsmokers.
c Adjusted for age and education; reference group is nonsmokers.
d P < 0.001, test for linear trend.
e Adjusted for age, education and hospital; reference group is 15–17 yrs.
f ORs were not computed because no current smokers started smoking before the age of 15 in Japanese controls.
g Adjusted for age and education; reference group is 15–17 yrs.
h P < 0.01, test for linear trend.