Table 4.
Hazard ratios (95% confidence intervals) for lung cancer according to coffee intake by smoking status, time since smoking cessation and number of cigarettes smoked per day in the NIH-AARP Diet and Health Study (N = 442 280)
| Coffee intake |
|||||||
|---|---|---|---|---|---|---|---|
| Smoking subgroup, cigarettes per day (n) | Cancer | None (ref.) | ≤ 1 cup/day | 2–3 cups/day | ≥ 4 cups/day | P-trend | |
| Never smokers (n = 147 706) | – | No. of cases | 66 | 188 | 144 | 33 | |
| HR (95% CI) | 1.00 | 1.13 (0.86-1.47) | 0.97 (0.74-1.29) | 1.08 (0.74-1.58) | 0.5699 | ||
| Former smokers (n = 228 875) | |||||||
| Quit ≥ 10 years ago | ≤ 10 (49 721) | No. of cases | 30 | 96 | 90 | 28 | |
| HR (95% CI) | 1.00 | 0.68 (0.45-1.03) | 0.60 (0.40-0.91) | 0.81 (0.48-1.36) | 0.6550 | ||
| 11–20 (53 718) | No. of cases | 48 | 218 | 295 | 76 | ||
| HR (95% CI) | 1.00 | 0.89 (0.65-1.21) | 0.88 (0.65-1.20) | 0.82 (0.57-1.18) | 0.4408 | ||
| 21–40 (53 447) | No. of cases | 49 | 285 | 516 | 210 | ||
| HR (95% CI) | 1.00 | 1.26 (0.93-1.71) | 1.42 (1.06-1.91) | 1.67 (1.23-2.28) | 0.0002 | ||
| >40 (18 877) | No. of cases | 27 | 134 | 249 | 112 | ||
| HR (95% CI) | 1.00 | 1.15 (0.76-1.75) | 1.32 (0.89-1.97) | 1.26 (0.82-1.91) | 0.2949 | ||
| Quit 5–9 years ago | ≤ 10 (5461) | No. of cases | 6 | 24 | 37 | 9 | |
| HR (95% CI) | 1.00 | 0.72 (0.30-1.77) | 0.89 (0.37-2.11) | 0.93 (0.33-2.61) | 0.5439 | ||
| 11–20 (10 003) | No. of cases | 15 | 78 | 136 | 41 | ||
| HR (95% CI) | 1.00 | 0.86 (0.49-1.50) | 1.00 (0.59-1.71) | 0.96 (0.59-1.71) | 0.5215 | ||
| 21–40 (13 487) | No. of cases | 25 | 135 | 254 | 116 | ||
| HR (95% CI) | 1.00 | 0.90 (0.59-1.38) | 0.96 (0.63-1.45) | 1.03 (0.67-1.60) | 0.3208 | ||
| >40 (4678) | No. of cases | 11 | 49 | 131 | 72 | ||
| HR (95% CI) | 1.00 | 0.82 (0.43-1.58) | 1.22 (0.66-2.25) | 1.03 (0.55-1.96) | 0.3323 | ||
| Quit 1–4 years ago | ≤ 10 (3365)a | No. of cases | 1 | 24 | 26 | 17 | |
| HR (95% CI) | – | – | – | – | – | ||
| 11–20 (6308) | No. of cases | 17 | 55 | 126 | 61 | ||
| HR (95% CI) | 1.00 | 0.61 (0.36-1.06) | 0.83 (0.50-1.38) | 0.97 (0.56-1.66) | 0.0446 | ||
| 21–40 (7659) | No. of cases | 18 | 77 | 189 | 113 | ||
| HR (95% CI) | 1.00 | 0.95 (0.57-1.59) | 1.11 (0.68-1.80) | 1.24 (0.75-2.05) | 0.0685 | ||
| >40 (2151) | No. of cases | 8 | 25 | 69 | 53 | ||
| HR (95% CI) | 1.00 | 0.64 (0.29-1.42) | 0.93 (0.45-1.94) | 0.90 (0.43-1.90) | 0.3415 | ||
| Current smokers (n = 65 699) | ≤ 10 (16 382) | No. of cases | 27 | 178 | 296 | 152 | |
| HR (95% CI) | 1.00 | 1.17 (0.78-1.76) | 1.21 (0.81-1.79) | 1.36 (0.90-2.04) | 0.1180 | ||
| 11–20 (26 081) | No. of cases | 74 | 266 | 722 | 556 | ||
| HR (95% CI) | 1.00 | 0.90 (0.69-1.16) | 1.03 (0.81-1.31) | 1.14 (0.89-1.45) | 0.0022 | ||
| 21–40 (20 769) | No. of cases | 72 | 217 | 637 | 750 | ||
| HR (95% CI) | 1.00 | 0.98 (0.75-1.28) | 1.00 (0.78-1.28) | 1.18 (0.93-1.51) | 0.0012 | ||
| >40 (2457) | No. of cases | 11 | 37 | 85 | 145 | ||
| HR (95% CI) | 1.00 | 1.28 (0.65-2.50) | 1.20 (0.64-2.25) | 1.38 (0.75-2.55) | 0.2852 | ||
Participants who smoked pipes/cigars but not cigarettes (n = 15 086) were excluded from model. Referent group was non-drinkers of coffee. Hazard ratios were adjusted for age at study baseline (continuous) and sex, current cigarette smoking status (current, former, never), number of cigarettes smoked per day (1–10, 11–20, 21–30, 31–40, 41–60, ≥ 60), time of smoking cessation among former smokers (< 1 year, 1 to < 5 years, 5 to < 10 years, or ≥ 10 years before baseline), whether a participant ever smoked pipe/cigars (yes/no).
aHazard estimates not provided for former smokers who quit 1–4 years ago and had smoked ≤ 10 cigarettes/day, due to small number of cases (n = 1) in referent group.