GPT and chronic obstructive pulmonary disease: Additional analyses showed that in males, low ALT level was a significant risk factor for COPD development on both univariable (HR: 1.341, 95% CI: 1.263–1.424, P < 0.0001) and multivariable Cox regression (HR: 1.097, 95% CI: 1.030–1.168, P = 0.0042) analyses (Fig. 3).