Lower respiratory illnesses promote FEV(1) decline in current smokers but not ex-smokers with mild chronic obstructive pulmonary disease: results from the lung health study.
Am J Respir Crit Care Med. 2001 Aug 1;164(3):358-64. doi: 10.1164/ajrccm.164.3.2010017. Am J Respir Crit Care Med. 2001. PMID: 11500333 Clinical Trial.