Table 2.
Levels of NK cell activity according to the clinical characteristics
| Clinical characteristic | NK cell activity (pg/mL) | P-value |
|---|---|---|
| Smoking status (3 categories) | ||
| Never smoker | 1,504 (656-2,697) | < 0.001 |
| Former smokers | 1,791 (802-2,856) | |
| Current smokers | 1,422 (623-2,592) | |
| Smoking status (2 categories) | ||
| Never or former smokers | 1,572 (685-2,741) | 0.001 |
| Current smokers | 1,422 (623-2,592) | |
| Urinary cotininea | ||
| < 50 ng/mL | 1,623 (716-2,802) | < 0.001 |
| ≥ 50 ng/mL | 1,434 (644-2,647) | |
| Age (yr) | ||
| < 40 (n = 6,797) | 1,602 (706-2,776) | < 0.001 |
| ≥ 40 (n = 5,452) | 1,483 (640-2,656) | |
| Sex | ||
| Male | 1,724 (761-2,815) | < 0.001 |
| Female | 1,318 (577-2,514) | |
| Obesity | ||
| No (BMI < 30 kg/m2) | 1,553 (678-2,724) | 0.213 |
| Yes (BMI ≥ 30 kg/m2) | 1,423 (600-2,680) | |
| Hypertension | ||
| No | 1,546 (674-2,725) | 0.663 |
| Yes | 1,536 (658-2,692) | |
| Diabetes mellitus | ||
| No | 1,552 (675-2,724) | 0.168 |
| Yes | 1,413 (603-2,631) | |
| Dyslipidemia | ||
| No | 1,542 (672-2,720) | 0.625 |
| Yes | 1,575 (680-2,735) | |
| Fatty liver | ||
| No | 1,531 (661-2,717) | 0.172 |
| Yes | 1,572 (706-2,733) | |
Values are presented as median (interquartile range). The levels of NK cell activity were compared using the non-parametric Mann–Whitney U-test or Kruskal–Wallis test. NK, natural killer; BMI, body mass index. aThere are missing values in 1,747 individuals.