Table 4.
Association of circulating IL-6, IL-8, and CRP levels with lung cancer risk in the PLCO study*
| Level of serum protein | Case patients (N = 532), No. (%) | Control subjects (N = 595), No. (%) | OR (95% CI)† | P‡ |
| IL-6 | ||||
| Low | 237 (44.6) | 304 (51.1) | 1.00 (referent) | .33 |
| High | 295 (55.4) | 291 (48.9) | 1.13 (0.88 to 1.46)§ | |
| IL-8 | ||||
| Low | 216 (40.6) | 300 (50.4) | 1.00 (referent) | .004 |
| High | 316 (59.4) | 295 (49.6) | 1.45 (1.13 to 1.86)‖ | |
| CRP | ||||
| Low | 219 (41.2) | 306 (51.4) | 1.00 (referent) | .007 |
| High | 313 (58.8) | 289 (48.6) | 1.41 (1.09 to 1.81)¶ | |
| IL-8 and CRP | ||||
| Low and low | 91 (17.1) | 154 (25.9) | 1.00 (referent) | |
| Low and high or high and low | 253 (47.6) | 298 (50.1) | 1.42 (1.03 to 1.95) | .03 |
| High and high | 188 (35.3) | 143 (24.0) | 2.11 (1.48 to 3.03) | 3.6 × 10−5 |
CI = confidence interval; CRP = C-reactive protein; IL-6 = interleukin 6; IL-8 = interleukin 8; OR =odds ratio; PLCO = Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.
Multivariable unconditional logistic regression adjusted for age (continuous), sex, smoking pack-years (continuous), smoking status (never, former quit ≤15 years, former quit >15 years, and current), year of randomization, and number of years in the study, dichotomized by the median values among control subjects (IL-6 4.0 pg/mL; IL-8 17.4 pg/mL; CRP 2.7 μg/mL).
P values were calculated using a two-sided Wald χ2 statistic.
Circulating marker levels were additionally adjusted for serum CRP and IL-8 levels.
Circulating marker levels were additionally adjusted for serum IL-6 and CRP levels.
Circulating marker levels were additionally adjusted for serum IL-6 and IL-8 levels.