SIRT1 and chronic obstructive pulmonary disease: Strikingly, no correlation between SIRT1 expression, lung function parameters, and TEAC levels was found (FEV1: p = 0.114, r2 = 0.103; FEV1/FVC: p = 0.513, r2 = 0.026; TEAC: p = 0.866, r2 = 0.006) in COPD patients.