The risk of lung cancer decreased by 22.3% for every 1-unit increase in LMR (OR = 0.777, 95% CI = 0.678–0.890; P <0.001) and by 41.8% for every 1-unit increase in the CD4+/CD8+ ratio (OR 0.582, 95% CI 0.503–0.674; P <0.001). The gene discussed is CD8A; the disease is lung cancer.