Current EC use was associated with 75% higher odds of chronic bronchitis, emphysema, or COPD compared with never users (Osei et al., 2020) as well as a marked increase in mucin production (Gundavarapu et al., 2012; Garcia-Arcos et al., 2016; Javed et al., 2017). Here, MUC5AC is linked to chronic obstructive pulmonary disease.