Table 5.

Involuntary smoking among never tobacco users and never alcohol 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*
    Never32/4091.0028/4091.008/4091.00
    Ever at home or at work51/4871.17 (0.68-2.01)57/4871.33 (0.78-2.26)18/4872.90 (1.09-7.73)
    Missing2/340/340/6
    Pheterogeneity0.520.670.52
Duration of involuntary smoking exposure at home (y)
    Never26/4771.0014/4771.0013/4211.00
    1-158/1032.27 (0.84-6.10)8/1032.83 (1.03-7.81)3/982.01 (0.43-9.36)
    >1510/1301.37 (0.56-3.35)9/1304.15 (1.50-11.47)7/1161.85 (0.53-6.49)
    Missing2/651/651/22
    Ptrend0.44<.010.28
    Pheterogeneity0.180.920.66
Duration of involuntary smoking exposure at work (y)
    Never25/4461.0015/4461.0012/4461.00
    1-155/1050.90 (0.26-3.10)3/1050.80 (0.21-3.13)4/1052.75 (0.71-10.61)
    >154/562.07 (0.49-8.72)4/563.99 (1.06-15.08)8/565.45 (1.69-17.52)
    Missing5/853/850/53
    Ptrend0.490.13<.01
    Pheterogeneity0.710.240.40
  • NOTE: Adjusted for centers, age, sex, race/ethnicity, and education.

  • * 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).