Table 3:
Odds ratios of lung cancer incidence comparing higher quintiles with the lowest quintile of circulating biomarkers stratified by smoking status
The Lung Cancer Cohort Consortium (LC3) Study (n = 5364 cases and 5364 controls)
| Smoking status and biomarker |
Odds Ratio (95% Confidence Interval) by quintiles of biomarkera | |||||
|---|---|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | Q5 | P trend | |
| Current smokers (2519 cases and 2519 controls) | ||||||
| Tryptophan (μmol/L) | 1.00 | 0.80 (0.66–0.98) | 0.79 (0.65–0.96) | 0.81 (0.66–0.98) | 0.78 (0.63–0.95) | 0.046 |
| Kynurenine (μmol/L) | 1.00 | 0.86 (0.72–1.04) | 1.04 (0.86–1.26) | 1.05 (0.86–1.28) | 1.16 (0.93–1.46) | 0.057 |
| KTR b | 1.00 | 0.94 (0.79–1.11) | 0.95 (0.79–1.13) | 1.04 (0.87–1.26) | 1.42 (1.15–1.75) | 0.005 |
| Quinolinic acid (nmol/L) | 1.00 | 0.97 (0.83–1.14) | 1.04 (0.87–1.24) | 1.26 (1.04–1.53) | 1.42 (1.14–1.76) | <0.001 |
| Neopterin (nmol/L) | 1.00 | 1.10 (0.91–1.34) | 1.21 (0.98–1.48) | 1.28 (1.02–1.61) | 1.45 (1.13–1.86) | 0.003 |
| Former smokers (1518 cases and 1518 controls) | ||||||
| Tryptophan (μmol/L) | 1.00 | 0.73 (0.58–0.92) | 0.81 (0.64–1.03) | 0.82 (0.65–1.04) | 0.74 (0.58–0.94) | 0.077 |
| Kynurenine (μmol/L) | 1.00 | 1.12 (0.84–1.49) | 1.23 (0.95–1.6) | 1.02 (0.78–1.34) | 1.08 (0.82–1.41) | 0.955 |
| KTR b | 1.00 | 1.06 (0.80–1.41) | 1.18 (0.89–1.54) | 1.13 (0.86–1.49) | 1.32 (1.00–1.74) | 0.035 |
| Quinolinic acid (nmol/L) | 1.00 | 1.00 (0.74–1.33) | 0.82 (0.62–1.08) | 1.17 (0.89–1.55) | 1.20 (0.90–1.59) | 0.037 |
| Neopterin (nmol/L) | 1.00 | 1.14 (0.86–1.50) | 1.14 (0.85–1.54) | 1.01 (0.74–1.37) | 1.34 (0.97–1.86) | 0.196 |
| Never smokers (1327 cases and 1327 controls) | ||||||
| Tryptophan (μmol/L) | 1.00 | 1.00 (0.80–1.26) | 1.04 (0.81–1.32) | 1.16 (0.88–1.53) | 0.87 (0.64–1.18) | 0.911 |
| Kynurenine (μmol/L) | 1.00 | 1.06 (0.85–1.33) | 1.12 (0.88–1.43) | 1.05 (0.8–1.38) | 1.17 (0.85–1.59) | 0.406 |
| KTR b | 1.00 | 1.00 (0.79–1.27) | 0.92 (0.72–1.19) | 0.92 (0.71–1.19) | 1.17 (0.88–1.54) | 0.562 |
| Quinolinic acid (nmol/L) | 1.00 | 0.89 (0.69–1.13) | 0.70 (0.54–0.9) | 0.92 (0.71–1.2) | 1.07 (0.79–1.44) | 0.707 |
| Neopterin (nmol/L) | 1.00 | 1.09 (0.85–1.40) | 1.18 (0.89–1.55) | 1.30 (0.97–1.74) | 1.19 (0.86–1.63) | 0.168 |
a
All models were adjusted for educational attainment (categorical), body mass index (kg/m2) (categorical), serum cotinine concentrations (continuous), estimated glomerular filtration rate (continuous), and cohort.
b
KTR, kynurenine to tryptophan ratio (x 1000).