TNF and chronic obstructive pulmonary disease: Some epidemiologic research on the association between TNF-α+489 G/A and -308 G/A polymorphism and COPD susceptibility have been performed (Cui et al., 2015; Zhang et al., 2016; Reséndiz-Hernández et al., 2018; Yu et al., 2021), but the results are still inconsistent.