Table 3.
Combined effects of smoking intensity and smoking duration on lung cancer among ever smokers
| EVER SMOKERS b | INTENSITY (cigarettes/day) | |||||
|---|---|---|---|---|---|---|
| < 10 | 10–19 | ≥20 | ||||
| Cases/Controls | OR (95%CI) a | Cases/Controls | OR (95%CI) a | Cases/Controls | OR (95%CI) a | |
| DURATION (years) | ||||||
| < 20 | 23/81 | 1.00 (Ref) | 26/41 | 2.08 (1.03; 4.19) | 13/28 | 1.74 (0.76; 3.99) |
| 20–39 | 36/65 | 1.62 (0.86; 3.07) | 134/65 | 6.17 (3.50; 10.89) | 88/40 | 7.50 (4.06; 13.87) |
| ≥ 40 | 21/29 | 2.47 (1.16; 5.26) | 126/44 | 10.26 (5.61; 18.75) | 107/22 | 19.02 (9.66; 37.46) |
| p interaction intensity*duration | 0.012 | |||||
Abbreviations: CI confidence interval, OR odds ratio
a Odds ratios adjusted for age (continuous), area of residence, education, and BMI 2 years before the interview (continuous)
b Ever smoker correspond to a person who have smoked at least 100 cigarettes throughout life