|  | Subcohort | Head-neck cancer cases | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
 |  |  | Overall | Subtypes | |||||||
 |  |  |  | OCCb | OHPCb | LCb |  | ||||
 | Categorical median | Person time at risk (years) | No. of cases | RR (95% CI) | No. of cases | RR (95% CI) | No. of cases | RR (95% CI) | No. of cases | RR (95% CI) | Pfor heterogeneity |
Cigarette smoking status | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Never smokers | Â | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | 0.97 |
Former smokers | Â | 22644 | 110 | 1.44 (0.97-2.14) | 24 | 0.70 (0.37-1.33) | 22 | 2.68 (1.00-7.14)i | 64 | 2.63 (1.26-5.47) | Â |
Current smokers | Â | 16657 | 241 | 4.49 (3.11-6.48) | 57 | 2.11 (1.23-3.62) | 55 | 8.53 (3.38-21.55) | 126 | 8.07 (3.94-16.54) | Â |
P for trendc | Â | Â | Â | <0.001 | Â | 0.001 | Â | <0.001 | Â | <0.001 | Â |
P for interaction with sexd | Â | Â | Â | 0.25 | Â | 0.08 | Â | 0.44 | Â | 0.46 | Â |
Cigarette smoking status, additionally adjusted for frequency and duration of cigarette smoking e | |||||||||||
Never smokers | Â | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | 0.97 |
Former smokers | Â | 22644 | 110 | 1.64 (1.08-2.49) | 24 | 0.79 (0.40-1.58) | 22 | 3.03 (1.09-8.45) | 64 | 2.87 (1.34-6.13) | Â |
Current smokers | Â | 16657 | 241 | 3.51 (2.36-5.23) | 57 | 1.91 (1.06-3.42) | 55 | 7.49 (2.87-19.54) | 126 | 5.26 (2.45-11.28) | Â |
P for trend | Â | Â | Â | <0.001 | Â | 0.03 | Â | <0.001 | Â | <0.001 | Â |
Frequency of cigarette smoking ( N /day) f | |||||||||||
Never smokers | 0 | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | 0.99 |
>0 to <20 | 10 | 24787 | 155 | 1.30 (0.84-2.01) | 38 | 0.63 (0.30-1.32) | 30 | 2.08 (0.73-5.94) | 85 | 2.32 (1.07-5.04) | Â |
≥20 | 20 | 14514 | 196 | 2.23 (1.45-3.44) | 43 | 1.06 (0.52-2.16) | 47 | 4.67 (1.64-13.34) | 105 | 3.75 (1.73-8.14) |  |
P for trend | Â | Â | Â | <0.001 | Â | 0.33 | Â | <0.001 | Â | <0.001 | Â |
Continuous, 10 cigarettes/day increments | Â | 64352 | 395 | 1.25 (1.13-1.38) | 110 | 1.20 (1.00-1.44)j | 83 | 1.42 (1.20-1.69) | 199 | 1.21 (1.08-1.36) | 0.71 |
Duration of cigarette smoking (years) g | |||||||||||
Never smokers | 0 | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | <0.001 |
>0 to <20 | 13 | 7433 | 20 | 1.00 (0.56-1.77) | 4 | 0.38 (0.13-1.17) | 5 | 2.11 (0.59-7.51) | 11 | 1.88 (0.75-4.69) | Â |
20 to <40 | 30 | 18999 | 105 | 1.44 (0.95-2.21) | 30 | 0.80 (0.41-1.59) | 25 | 2.74 (0.98-7.68) | 50 | 2.35 (1.09-5.06) | Â |
≥40 | 43 | 12868 | 226 | 2.45 (1.49-4.02) | 47 | 0.98 (0.39-2.46) | 47 | 3.89 (1.22-12.40) | 129 | 4.81 (2.11-11.00) |  |
P for trend | Â | Â | Â | <0.001 | Â | 0.87 | Â | 0.02 | Â | <0.001 | Â |
Continuous, 10 years increments | Â | 64352 | 395 | 1.28 (1.14-1.42) | 110 | 1.03 (0.85-1.24) | 83 | 1.36 (1.09-1.70) | 199 | 1.49 (1.25-1.78) | 0.25 |
Pack-years of cigarette smoking h | |||||||||||
Never smokers | 0 | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | 1.00 |
>0 to <20 | 9 | 20832 | 96 | 1.16 (0.77-1.76) | 24 | 0.58 (0.30-1.14) | 20 | 2.12 (0.77-5.80) | 51 | 2.07 (0.97-4.41) | Â |
20 to <40 | 28 | 12732 | 132 | 1.65 (1.04- 2.60) | 32 | 0.84 (0.39-1.83) | 26 | 2.87 (0.94-8.79) | 73 | 2.93 (1.33-6.48) | Â |
≥40 | 48 | 5736 | 123 | 2.82 (1.76-4.50) | 25 | 1.28 (0.58-2.82) | 31 | 6.49 (2.11-19.95) | 66 | 4.79 (2.15-10.64) |  |
P for trend | Â | Â | Â | <0.001 | Â | 0.07 | Â | <0.001 | Â | <0.001 | Â |
Continuous, 10 pack-years increments | Â | 64352 | 395 | 1.18 (1.11-1.25) | 110 | 1.16 (1.04-1.28) | 83 | 1.24 (1.12-1.36) | 199 | 1.16 (1.09-1.24) | 0.77 |
Cigarette smoking cessation i | |||||||||||
Never smokers | 25 | 25051 | 44 | 1 (reference) | 29 | 1 (reference) | 6 | 1 (reference) | 9 | 1 (reference) | <0.001 |
Stopped ≥20 years | 14 | 6953 | 24 | 1.25 (0.72-2.19) | 5 | 0.63 (0.22-1.81) | 6 | 3.35 (0.97-11.55) | 13 | 1.92 (0.79-4.70) |  |
Stopped 10 to <20 years | 5 | 7717 | 36 | 1.49 (0.91-2.43) | 8 | 0.78 (0.32-1.86) | 8 | 3.29 (1.04-10.39) | 20 | 2.45 (1.07-5.61)k | Â |
Stopped >0 to <10 years | 0 | 7918 | 50 | 1.73 (1.09-2.76) | 11 | 0.84 (0.39-1.83) | 8 | 2.48 (0.77-7.93) | 31 | 3.45 (1.56-7.62) | Â |
Current smokers | Â | 16657 | 241 | 4.26 (2.93-6.20) | 57 | 2.03 (1.16-3.56) | 55 | 8.10 (3.14-20.87) | 126 | 7.53 (3.65-15.51) | Â |
P for trend | Â | Â | Â | <0.001 | Â | 0.004 | Â | <0.001 | Â | <0.001 | Â |