Table 3.

Involuntary smoking among never tobacco users, involuntary smoking among never tobacco users and never alcohol drinkers, and risk of head and neck cancer

Never tobacco users
Never tobacco/alcohol users
Cases/controlsOR* (95% CI)Cases/controlsOR* (95% CI)
Ever involuntary smoking exposure
    Never186/7941.0087/4091.00
    Ever at home or at work303/1,0781.07 (0.85-1.34)149/4871.30 (0.94-1.81)
    Ever at home only117/3961.15 (0.87-1.53)68/2171.37 (0.93-2.03)
    Ever at work only93/3750.97 (0.72-1.31)38/1441.25 (0.78-1.98)
    Ever at home and at work88/2831.03 (0.75-1.42)41/1151.22 (0.76-1.97)
    Missing5/673/34
    Pheterogeneity0.230.78
Duration of involuntary smoking exposure at home (y)
    Never184/1,0741.0074/4771.00
    1-1570/2941.28 (0.91-1.80)32/1032.04 (1.21-3.43)
    >1563/2511.60 (1.12-2.28)36/1301.75 (1.06-2.90)
    Missing20/1437/65
    Ptrend<.01<.01
    Pheterogeneity0.330.07
Frequency of involuntary smoking exposure at home§ (h/d)
    0-3116/6961.0052/3451.00
    >315/811.76 (0.83-3.73)5/206.11 (0.03-1449)
    Missing65/34332/158
    Pheterogeneity0.760.04
Duration of involuntary smoking exposure at work (y)
    Never174/8981.0075/4461.00
    1-1554/3090.86 (0.60-1.24)19/1051.12 (0.61-2.06)
    >1547/1851.55 (1.04-2.30)19/562.59 (1.35-4.95)
    Missing33/17318/85
    Ptrend0.13<.01
    Pheterogeneity0.410.29
Frequency of involuntary smoking exposure at work** (h/d)
    Never107/4991.0050/2391.00
    1-319/1121.16 (0.001-6.01)7/242.04 (0.69-6.07)
    >330/1321.14 (0.04-32.76)9/411.16 (0.46-2.96)
    Missing3/253/10
    Ptrend0.680.47
    Pheterogeneity0.040.88
  • * Adjusted for centers, age, sex, race/ethnicity, education, and alcohol drinking (in drink-years; for never tobacco users only).

  • Included Central Europe, Tampa, Latin America, Los Angeles, and Houston studies.

  • Included Central Europe, Tampa, Latin America, Los Angeles, and Puerto Rico studies.

  • § Included Central Europe, Tampa, and Latin America studies.

  • Estimates from random effect models.

  • Included Central Europe, Tampa, Latin America, and Los Angeles studies.

  • ** Included Central Europe and Latin America studies.