Table 4.

Involuntary smoking among never tobacco users and risk of head and neck cancer, by cancer subsite

Oral cavity
Pharynx
Larynx
Cases/controlsOR* (95% CI)Cases/controlsOR*, (95% CI)Cases/controlsOR* (95% CI)
Ever involuntary smoking exposure
    Never53/7941.0072/7941.0023/7941.00
    Ever at home or at work76/1,0780.93 (0.61-1.41)135/1,0781.30 (0.31-5.34)45/1,0781.71 (0.98-3.00)
    Missing2/671/670/16
    Pheterogeneity0.56<0.010.36
Duration of involuntary smoking exposure at home§ (y)
    Never46/1,0741.0053/1,0741.0036/9381.00
    1-1512/2941.58 (0.73-3.41)27/2941.88 (0.42-8.50)8/2781.44 (0.59-3.53)
    >1516/2511.06 (0.53-2.11)16/2514.13 (1.43-11.89)15/2212.58 (1.20-5.57)
    Missing4/1435/1433/68
    Ptrend0.780.020.02
    Pheterogeneity0.230.240.77
Duration of involuntary smoking exposure at work (y)
    Never46/8981.0048/8981.0034/8981.00
    1-159/3090.65 (0.28-1.51)19/3090.81 (0.26-2.50)9/3090.98 (0.43-2.23)
    >1510/1851.31 (0.57-3.00)13/1855.16 (0.28-95.95)17/1852.07 (1.04-4.11)
    Missing6/1739/1731/116
    Ptrend0.750.370.07
    Pheterogeneity0.970.020.66
  • * Adjusted for centers, age, sex, race/ethnicity, education, and alcohol drinking (in drink-years).

  • Estimates from random-effects model.

  • Included Central Europe, Tampa, Latin America, Los Angeles, and Houston studies (no Tampa study for larynx).

  • § Included Central Europe, Tampa, Puerto Rico, Latin America, and Los Angeles studies (no Tampa and Puerto Rico studies for larynx).

  • Included Central Europe, Tampa, Latin America, and Los Angeles studies (no Tampa study for larynx).