Tables 3.
Marijuana smoking and the risk of head and neck cancer
| Case | Controls | OR* | 95% CI | |
|---|---|---|---|---|
| Total | 4029 | 5015 | ||
| Marijuana smoking | ||||
| Never | 3538 | 4199 | 1.00 | Ref |
| Ever | 402 | 736 | 0.88 | (0.67, 1.16) |
| Missing | 89 | 80 | ||
| p for heterogeneity | 0.07 | |||
| Frequency of marijuana smoking (times per day)~ | ||||
| Never | 3339 | 3319 | 1.00 | |
| 0–1 | 298 | 630 | 0.87 | (0.61, 1.25) |
| >1–3 | 49 | 61 | 0.71 | (0.35, 1.47) |
| >3 | 42 | 42 | 0.87 | (0.40, 1.89) |
| Missing | 94 | 66 | ||
| p for trend | 0.26 | |||
| p for heterogeneity | 0.03 | |||
| Duration of marijuana smoking (in years)~ | ||||
| Never | 3339 | 3319 | 1.00 | Ref |
| >0–5 | 150 | 319 | 0.81 | (0.53, 1.23) |
| >5–10 | 65 | 129 | 0.87 | (0.48, 1.57) |
| >10–20 | 74 | 145 | 0.82 | (0.46, 1.44) |
| >20 | 100 | 140 | 0.94 | (0.53, 1.66) |
| Missing | 94 | 66 | ||
| p for trend | 0.77 | |||
| p for heterogeneity | 0.36 | |||
| Cumulative exposure (joint-year) #~ | ||||
| Never | 3339 | 3319 | 1.00 | Ref |
| >0–2 | 208 | 476 | 0.89 | (0.60, 1.31) |
| >2–5 | 36 | 77 | 0.70 | (0.31, 1.56) |
| >5 | 145 | 180 | 0.86 | (0.54, 1.37) |
| Missing | 94 | 66 | ||
| p for trend | 0.22 | |||
| p for heterogeneity | 0.04 | |||
*
Random effect estimates. Adjusted for age (categorical), sex, race, education level, study, packyear (continuous), alcohol duration (continuous), duration of smoking pipe (continuous), duration of smoking cigar (continuous). Likelihood Heterogeneity test by study.
~
Tampa study excluded
#
A joint-year is the number of joints per day multiplied by the duration of marijuana smoking in years (1 joint-year being equivalent to 1 joint per day for one year or 365 joints lifetime).