The reduced club cell numbers in the airways of smokers and COPD patients, respectively7,15, are associated with reduced uteroglobin (SCGB1A1) serum levels, which were correlated to a decline in FEV1 (Forced Expiratory Volume in 1 Second) and COPD disease progression14,52. This evidence concerns the gene SCGB1A1 and chronic obstructive pulmonary disease.