Table 5.
Marijuana smoking and the risk of head and neck cancer by tobacco and alcohol status
| Never tobacco users1* | Never alcohol users2 | |||||||
|---|---|---|---|---|---|---|---|---|
| Cases | Controls | OR | 95% CI | Cases | Controls | OR | 95% CI | |
| Total | 353 | 1017 | 345 | 997 | ||||
| Marijuana smoking | ||||||||
| Never | 295 | 797 | 1.00 | Ref | 311 | 915 | 1.00 | Ref |
| Ever | 57 | 220 | 0.93 | (0.63, 1.37) | 34 | 79 | 1.27 | (0.77, 2.12) |
| Missing | 1 | 0 | 0 | 3 | ||||
| p for heterogeneity | 0.21 | 0.06 | ||||||
| Frequency of marijuana smoking (times per day) | ||||||||
| Never | 295 | 797 | 1.00 | Ref | 311 | 915 | 1.00 | Ref |
| 0–1 | 52 | 205 | 0.93 | (0.62, 1.39) | 26 | 68 | 1.30 | (0.74, 2.28) |
| >1 | 5 | 15 | 0.92 | (0.31, 2.68) | 8 | 11 | 1.18 | (0.43, 3.19) |
| Missing | 1 | 0 | 0 | 3 | ||||
| p for trend | 0.72 | 0.42 | ||||||
| p for heterogeneity | 0.06 | 0.22 | ||||||
| Duration of marijuana smoking (in years) | ||||||||
| Never | 295 | 797 | 1.00 | Ref | 311 | 915 | 1.00 | Ref |
| >0–5 | 31 | 113 | 0.99 | (0.62, 1.57) | 12 | 45 | 0.86 | (0.42, 1.77) |
| >5–10 | 9 | 47 | 0.69 | (0.32, 1.51) | 6 | 11 | 1.22 | (0.41, 3.61) |
| >10–20 | 6 | 35 | 0.60 | (0.24, 1.50) | 6 | 13 | 1.38 | (0.47, 4.04) |
| >20 | 11 | 25 | 1.60 | (0.73, 3.52) | 10 | 10 | 3.12 | (1.17, 8.36) |
| Missing | 1 | 0 | 0 | 3 | ||||
| p for trend | 0.99 | 0.05 | ||||||
| p for heterogeneity | 0.53 | 0.18 | ||||||
| Cumulative exposure (joint-year) | ||||||||
| Never | 295 | 797 | 1.00 | Ref | 311 | 915 | 1.00 | Ref |
| >0–2 | 41 | 176 | 0.87 | (0.57, 1.33) | 16 | 59 | 0.99 | (0.52, 1.88) |
| >2–5 | 5 | 18 | 0.89 | (0.31, 2.53) | 3 | 10 | 0.58 | (0.15, 2.26) |
| >5 | 11 | 26 | 1.34 | (0.62, 2.92) | 15 | 10 | 3.25 | (1.31, 8.02) |
| Missing | 1 | 0 | 0 | 3 | ||||
| p for trend | 0.80 | 0.07 | ||||||
| p for heterogeneity | 0.17 | 0.23 | ||||||
*
Never tobacco user are never user of cigarette, pipe, cigar, chew and snuff. Does not include Tampa and Latin America studies
1
OR adjusted for age (categorical), sex, race, study, education_level, alcohol_duration (continuous). Does not include Tampa and Latin America studies
2
OR adjusted for age (categorical), sex, race, study, education_level, packyear (continuous) duration of smoking pipe (continuous) and duration of smoking cigar (continuous). Does not include Seattle and Latin America studies