Table 2

Estimated effects of ETS (OR and 95% CI) on the risk of head and neck cancer, by covariates selected for adjustment

No. of casesNo. of controlsNo covariates (crude)Pack-years of smokingPack-years of smoking plusa
ETS
Neverb10271.01.01.0
Ever1451392.8 (1.3–6.0)2.1 (0.9–5.0)2.4 (0.9–6.8)
Degree of ETS exposure
Neverb10271.01.01.0
Moderate981152.3 (1.1–5.0)1.8 (0.7–4.2)2.1 (0.7–6.1)
Heavyc47245.3 (2.2–12.7)3.7 (1.4–9.7)3.6 (1.1–11.5)
P for trend0.00010.00390.0249
ETS at home
Never37601.01.01.0
Occasionally41461.4 (0.8–2.6)1.4 (0.7–2.7)1.6 (0.8–3.3)
Regularly77602.1 (1.2–3.5)1.5 (0.9–2.8)1.7 (0.8–3.3)
P for trend0.00650.15960.1574
ETS at work
Never36551.01.01.0
Occasionally46501.4 (0.8–2.5)1.2 (0.6–2.3)1.0 (0.5–2.1)
Regularly73611.8 (1.1–3.1)1.4 (0.8–2.7)1.0 (0.5–2.1)
P for trend0.02880.23800.9240
Spouse smoking
No801041.01.01.0
Yes33222.0 (1.1–3.6)1.6 (0.8–3.1)1.7 (0.8–3.7)
  • a Also adjusted for age (continuous variable); gender (male, 0; female, 1); race (white, 0; non-white, 1); education (≤high school, 0; college, 2; >college, 2); heavy alcohol use (<100/month, 0; ≥100/month, 1); and marijuana use (no, 0; yes, 1).

  • b Never exposed to ETS at both home and work.

  • c Regularly exposed to ETS at both home and work.