Table 1

Risk of brain glioma associated with cigarette smoking in Iowa

Cigarette smokingMenWomen
Case/ControlORa (95% CI)Case/ControlORa (95% CI)
Never69/5331.0121/5741.0
Ever132/10680.9 (0.6–1.2)53/2590.8 (0.6–1.2)
Ex-smoker71/7420.8 (0.5–1.1)27/1201.0 (0.6–1.6)
Current smoker61/3261.0 (0.7–1.6)26/1390.7 (0.4–1.1)
Duration (yr)
 <3049/3580.8 (0.5–1.2)22/761.1 (0.7–2.0)
 30–4042/3050.9 (0.6–1.4)15/840.6 (0.3–1.2)
 >4037/4020.9 (0.5–1.4)10/990.4 (0.2–0.9)
 Unknown4/36/0
Number of cigarettes per day:
 <1123/1970.9 (0.6–1.6)16/940.7 (0.4–1.3)
 11–2049/4480.8 (0.5–1.2)25/1031.0 (0.6–1.7)
 >2060/4230.9 (0.6–1.4)12/620.7 (0.3–1.4)
Pack-years:
 <2541/3370.8 (0.5–1.3)23/1100.8 (0.5–1.4)
 25–4940/3410.8 (0.5–1.3)16/940.6 (0.3–1.2)
 >4947/3870.9 (0.6–1.4)8/550.6 (0.3–1.3)
 Unknown4/36/0
  • a OR, odds ratio. Adjusted for age (40–54, 55–64, 65–74, and 75–85 years), body mass index (<24, 24–26, >26 kg/m2), level of education (≤8, 9–11, 12–15, ≥16 years), strenuous or moderate exercise (≤1×/day, 2–6×/week, 1–4×/month, <1×/year), duration of living in a residence served by chlorinated surface water (0, 1–19, 20–39, ≥40 years), and having a first-degree relative with brain cancer (yes/no).