UGT1A1 rs887829/smoking status* | Lung cancer incidence per 10 000 PYs (95% CI) | IRR (95% CI)* | P value* for within smoking comparison | Lung cancer predicted incidence difference per 10 000 person years (95% CI)† | P value† for within smoking comparison |
TT/never | 1.8 (1.2 to 2.7) | 1.0 (ref) | Ref | Ref | |
CC or CT/never | 1.9 (1.7 to 2.2) | 1.1 (0.7 to 1.6) | 0.82 | 0.1 (−0.6 to 0.8) | 0.81 |
TT/former | 9.4 (7.5 to 11.6) | 4.2 (2.7 to 6.5) | Ref | Ref | |
CC or CT/former | 10.1 (9.4 to 10.8) | 4.5 (3.2 to 6.7) | 0.54 | 0.60 (−1.2 to 2.4) | 0.54 |
TT/current | 21.4 (16.5 to 27.8) | 12.8 (8.0 to 20.4) | Ref | Ref | |
CC or CT/current | 30.1 (28.6 to 33.1) | 18.6 (12.6 to 27.6) | 0.0076 | 11.1 (4.1 to 18.1) | 0.0019 |
Regular smokers (cigarettes per day)† | |||||
TT/former 1–19 | 8.2 (5.4 to 12.6) | 1.0 (ref) | Ref | ||
CC or CT/ former 1–19 | 7.7 (6.7 to 8.9) | 0.9 (0.6 to 1.5) | 0.78 | −0.5 (−4.0 to 3.1) | 0.79 |
TT/former ≥20 | 14.9 (11.3 to 19.7) | 1.7 (1.0 to 2.9) | Ref | ||
CC or CT/former ≥20 | 17.4 (16 to 18.9) | 2.0 (1.3 to 3.1) | 0.33 | 2.0 (−2.0 to 6.2) | 0.31 |
TT/current 1–19 | 24.7 (17.1 to 35.8) | 4.1 (2.3 to 7.1) | Ref | ||
CC or CT/ current 1–19 | 27.3 (24.3 to 30.8) | 4.5 (2.9 to 7.0) | 0.60 | 3.6 (−9.0 to 16.1) | 0.58 |
TT/current ≥20 | 26.8 (16.9 to 42.5) | 4.5 (2.4 to 8.4) | Ref | ||
CC or CT/current ≥20 | 54.9 (49.5 to 61) | 9.4 (6 to 14.6) | 0.0023 | 38.7 (20.6 to 56.9) | <0.0001 |
*Rate ratios on the multiplicative (relative) scale and adjusted for age, gender, calendar year, ethnicity (first 40 principal components) and recruitment centre.
†Marginal effect on the additive (incidence) scale and adjusted for age, gender, calendar year, ethnicity (first 40 principal components) and recruitment centre.
IRR, incidence rate ratio; PYs, person-years.