CFTR and chronic obstructive pulmonary disease: Nasal CFTR activity in smokers with or without chronic obstructive pulmonary disease (COPD) is significantly impaired and associated with symptoms of chronic bronchitis (Sloane et al., 2012; Dransfield et al., 2013), suggesting observed changes in response to VG-containing aerosols could potentially lead to reduced MCC in e-cig users.