The COPD CB+ group had a greater goblet cell density compared to the COPD CB- group (7.91±2.89 vs. 3.88±2.33 cells/mm, p = .018), but there was not a significant difference in mucin volume density (17.51±15.74 vs. 10.00±9.90 μL/mm2, p = .286). Here, MUC5AC is linked to chronic obstructive pulmonary disease.