Table 2

Adjusteda odds ratio estimates and 95% confidence intervals for pack-years and years of smoking among all subjects and by smoking status, Ontario, Canada, 1995–1996

Pack-yearsCases/controlsOdds ratio95% confidence interval
All subjects
 0 (nonsmoker)70/1121.00
 >0 to ≤531/341.56(0.87–2.82)
 >5 to ≤1233/341.61(0.89–2.92)
 >12 to ≤2434/321.96(1.04–3.69)
 >2430/322.31(1.12–4.77)
Current smokers
 0 (nonsmoker)70/1121.00
 >0 to ≤512/141.24(0.53–2.92)
 >5 to ≤1220/201.79(0.74–3.04)
 >12 to ≤2422/221.50(0.87–3.67)
 >2418/211.86(0.82–4.22)
Former smokers
 0 (nonsmoker)70/1121.00
 >0 to ≤522/171.98(0.92–4.25)
 >5 to ≤1213/142.23(0.90–5.51)
 >12 to ≤2412/102.59(0.92–6.79)
 >2412/113.30(1.03–10.57)
Years of smoking
 All subjects
  0 (nonsmoker)70/1121.00
  >0 to ≤1038/411.67(0.90–3.18)
  >10 to ≤1522/261.52(0.71–3.24)
  >15 to ≤2131/301.90(0.89–4.05)
  >2131/363.18(1.32–7.64)
 Current smokers
  0 (nonsmoker)70/1121.00
  >0 to ≤1016/181.21(0.49–3.01)
  >10 to ≤1512/141.26(0.45–3.49)
  >15 to ≤2120/211.67(0.61–4.57)
  >2124/242.73(0.85–8.75)
 Former smokers
  0 (nonsmoker)70/1121.00
  >0 to ≤1022/231.53(0.67–3.52)
  >10 to ≤1510/121.92(0.63–5.88)
  >15 to ≤2111/92.36(0.70–7.92)
  >2112/75.39(1.19–24.46)
  • a Adjusted for education, age, combined moderate and strenuous recreational physical activity at adolescence, body mass index, and for years smoked, average number of cigarettes smoked/day (continuous).