Table 3.
Involuntary smoking among never tobacco users, involuntary smoking among never tobacco users and never alcohol drinkers and the risk of head and neck cancer
| Never Tobacco Users | Never Tobacco/Alcohol Users | |||||||
|---|---|---|---|---|---|---|---|---|
| Ca | Co | OR* | 95 %CI | Ca | Co | OR* | 95 %CI | |
| Ever IS exposure1 | ||||||||
| never | 186 | 794 | 1.00 | 87 | 409 | 1.00 | ||
| ever at home or at work | 303 | 1078 | 1.07 | ( 0.85, 1.34) | 149 | 487 | 1.30 | ( 0.94, 1.81) |
| ever at home only | 117 | 396 | 1.15 | (0.87, 1.53) | 68 | 217 | 1.37 | (0.93, 2.03) |
| ever at work only | 93 | 375 | 0.97 | (0.72, 1.31) | 38 | 144 | 1.25 | (0.78, 1.98) |
| ever at home and work | 88 | 283 | 1.03 | (0.75, 1.42) | 41 | 115 | 1.22 | (0.76, 1.97) |
| Missing | 5 | 67 | 3 | 34 | ||||
| P for heterogeneity | 0.23 | 0.78 | ||||||
| Duration of IS exposure at home2 | ||||||||
| never | 184 | 1074 | 1.00 | 74 | 477 | 1.00 | ||
| 1-15 years | 70 | 294 | 1.28 | ( 0.91, 1.80) | 32 | 103 | 2.04 | ( 1.21, 3.43) |
| >15 years | 63 | 251 | 1.60 | ( 1.12, 2.28) | 36 | 130 | 1.75 | ( 1.06, 2.90) |
| Missing | 20 | 143 | 7 | 65 | ||||
| P for trend | <.01 | <.01 | ||||||
| P for heterogeneity | 0.33 | 0.07 | ||||||
| Frequency of IS exposure at home3 | ||||||||
| 0-3 hours/day | 116 | 696 | 1.00 | 52 | 345 | 1.00 | ||
| >3 hours/day | 15 | 81 | 1.76 | ( 0.83, 3.73) | 5 | 20 | 6.11** | ( 0.03, 1449) |
| Missing | 65 | 343 | 32 | 158 | ||||
| P for heterogeneity | 0.76 | 0.04 | ||||||
| Duration of IS exposure at work4 | ||||||||
| never | 174 | 898 | 1.00 | 75 | 446 | 1.00 | ||
| 1-15 years | 54 | 309 | 0.86 | ( 0.60, 1.24) | 19 | 105 | 1.12 | ( 0.61, 2.06) |
| >15 years | 47 | 185 | 1.55 | ( 1.04, 2.30) | 19 | 56 | 2.59 | ( 1.35, 4.95) |
| Missing | 33 | 173 | 18 | 85 | ||||
| P for trend | 0.13 | <.01 | ||||||
| P for heterogeneity | 0.41 | 0.29 | ||||||
| Frequency of IS exposure at work5 | ||||||||
| never | 107 | 499 | 1.00 | 50 | 239 | 1.00 | ||
| 1-3 hours/day | 19 | 112 | 1.16** | ( 0.001,601) | 7 | 24 | 2.04 | ( 0.69, 6.07) |
| >3 hours/day | 30 | 132 | 1.14** | ( 0.04,32.76) | 9 | 41 | 1.16 | ( 0.46, 2.96) |
| Missing | 3 | 25 | 3 | 10 | ||||
| P for trend | 0.68 | 0.47 | ||||||
| P for heterogeneity | 0.04 | 0.88 | ||||||
*
Adjusted for centers, age, sex, race/ethnicity, education and alcohol drinking (in drink-years; for never tobacco users only).
**
Estimates from random effect models.
1
Included Central Europe, Tampa, Latin America, Los Angeles, and Houston studies.
2
Included Central Europe, Tampa, Latin America, Los Angeles, and Puerto Rico studies.
3
Included Central Europe, Tampa, and Latin America studies.
4
Included Central Europe, Tampa, Latin America, and Los Angeles studies.
5
Included Central Europe and Latin America studies.