ISAYA (1998/2000)GEIRD (2007/2010)p-value
(n=8,931)(n=5,162)
Non-smokers7.5% (7.1–7.9)9.1% (8.2–10.1)0.01
Past smokers11.2% (10.6–11.9)10.4% (9.9–10.9)0.11
Current smokers19.3% (18.4–20.2)21.2% (18.4–24.3)0.32
Total12.4% (11.9–12.8)12.6% (11.5–13.9)0.74
  • *Adjusted for centre, type of contact (telephone vs mail), cumulative response rate, season of response, sex, age.