Table 2. The Effect of nicotine dependence on the risk of lung cancer and head and neck cancer separately, mediated through duration of smoking.
| Lung Cancer | Head and Neck Cancer | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | (95%CI) | Effect Type | Estimate | (95%CI) | PM | OR | (95%CI) | Effect Type | Estimate | (95%CI) | PM | ||
| 1. How soon after you wake up do you smoke your first cigarette? | After 60 min | Reference | Direct | 1.59 | (1.39, 1.81) | 63% | Reference | Direct | 1.37 | (1.19, 1.58) | 73% | ||
| 31–60 min | 1.91 | (1.35, 2.71) | 1.38 | (0.93, 2.06) | |||||||||
| 6–30 min | 2.62 | (1.86, 3.69) | Indirect | 1.12 | (1.05, 1.19) | 2.23 | (1.54, 3.22) | Indirect | 1.06 | (1.02, 1.11) | |||
| Within 5 min | 3.40 | (2.22, 5.23) | 2.26 | (1.41, 3.62) | |||||||||
| 2. Do you find it difficult to refrain from smoking in places where it is forbidden? | No | Reference | Direct | 1.67 | (1.20, 2.34) | 60% | Reference | Direct | 0.90 | (0.60, 1.35) | n/a | ||
| Yes | 1.78 | (1.28, 2.48) | Indirect | 1.31 | (1.09, 1.58) | 0.96 | (0.65, 1.43) | Indirect | 1.30 | (1.06, 1.58) | |||
| 3. Which cigarette would you hate most to give up? | Any Other Time | Reference | Direct | 2.18 | (1.60, 2.97) | 46% | Reference | Direct | 1.92 | (1.39, 2.66) | 52% | ||
| The first in the morning | 2.08 | (1.56, 2.77) | Indirect | 1.31 | (1.10, 1.55) | 1.93 | (1.40, 2.67) | Indirect | 1.17 | (1.04, 1.32) | |||
| 4. How many cigarettes per day do you smoke? | 10 or less | Reference | Direct | 1.57 | (1.34, 1.84) | 64% | Reference | Direct | 1.06 | (0.91, 1.22) | 95% | ||
| 11–20 | 2.43 | (1.78, 3.31) | 1.31 | (0.97, 1.76) | |||||||||
| 21–30 | 3.49 | (2.37, 5.13) | Indirect | 1.17 | (1.09, 1.26) | 1.47 | (0.99, 2.18) | Indirect | 1.11 | (1.06, 1.17) | |||
| 31 or more | 2.33 | (1.40, 3.87) | 0.84 | (0.50, 1.40) | |||||||||
| 5. Do you smoke more frequently during the first hours after awakening than during the rest of the day? | No | Reference | Direct | 2.03 | (1.38, 2.98) | 49% | Reference | Direct | 1.88 | (1.22, 2.88) | 53% | ||
| Yes | 2.11 | (1.43, 3.10) | Indirect | 1.18 | (0.97, 1.44) | 1.88 | (1.24, 2.85) | Indirect | 1.10 | (0.95, 1.27) | |||
| 6. Do you smoke even if you are so ill that you are in bed most of the day? | No | Reference | Direct | 1.04 | (0.75, 1.44) | 96% | Reference | Direct | 0.59 | (0.41, 0.87) | n/a | ||
| Yes | 1.04 | (0.76, 1.44) | Indirect | 1.33 | (1.11, 1.60) | 0.62 | (0.42, 0.90) | Indirect | 1.17 | (1.01, 1.36) | |||
| Total Fagerström Score | 1.20 | (1.13, 1.27) | Direct | 1.20 | (1.13, 1.28) | 83% | 1.12 | (1.05, 1.20) | Direct | 1.12 | (1.04, 1.19) | 89% | |
| Indirect | 1.06 | (1.03, 1.09) | Indirect | 1.04 | (1.01, 1.06) | ||||||||
Models are adjusted for age, sex, ethnicity, education, smoking status, age started smoking, and family history of lung/HNC cancer. Additionally, for the HNC model, it was also adjusted for average daily alcohol consumption (grams/day). The table demonstrates the odds ratio and 95% confidence interval (OR, 95%CI) and the mediated effects associated with each Fagerström dependence variable (Items 1–6) and for the total Fagerström score (accumulated score from the scores for each of the nicotine dependence variables). “PM” is the Proportion Mediated through smoking duration. “n/a” refers to occurrences when the proportion mediated could not be estimated when the total and indirect effects were in opposite directions.