Table 4.
Association of NK cell activity with the number of cigarettes smoked and duration of smoking, among current smokers
| Smoking status | NK cell activity | Univariable analysis | P-value | Multivariable analysisb | P-value | |
|---|---|---|---|---|---|---|
| < 500 pg/mL (n = 339) | ≥ 500 pg/mL (n = 1,322) | |||||
| Daily number of cigarettes smoked | ||||||
| < 10 cigarettes/d | 81 (17.7) | 376 (82.3) | 1 | 1 | ||
| 10-19 cigarettes/d | 173 (19.8) | 701 (80.2) | 1.61 (1.14-2.27) | 0.007 | 1.67 (1.17-2.39) | 0.005 |
| ≥ 20 cigarettes/d | 85 (25.8) | 245 (74.2) | 1.41 (1.04-1.89) | 0.025 | 1.36 (1.005-1.84) | 0.046 |
| Duration of cigarette smoking | ||||||
| < 20 yr | 124 (18.1) | 561 (81.9) | 1 | 1 | ||
| ≥ 20 yr | 215 (22.0) | 761 (78.0) | 1.28 (0.999-1.64) | 0.051 | 1.11 (0.80-1.54) | 0.522 |
| Total number of cigarettes smoked | ||||||
| < 10 pack-years | 126 (17.1) | 612 (82.9) | 1 | 1 | ||
| ≥ 10 pack-years | 213 (23.1) | 710 (76.9) | 1.46 (1.14-1.86) | 0.003 | 1.45 (1.10-1.92) | 0.008 |
| Urinary cotininea | ||||||
| < 50 ng/mL | 28 (14.7) | 162 (85.3) | 1 | 1 | ||
| ≥ 50 ng/mL | 242 (21.1) | 906 (79.8) | 1.55 (1.01-2.37) | 0.045 | 1.53 (0.998-2.34) | 0.051 |
Values are presented as number (%) or OR (95% CI). NK, natural killer. aThere are missing values in 323 individuals. bValues were adjusted for age and sex.