We used two different measures of goblet cell hyperplasia (goblet cell density for goblet cell number and mucin volume density to assess for hyperplasia) to show that smokers without airflow obstruction and COPD subjects had a greater goblet cell density compared to nonsmokers, and that smokers without airflow obstruction had a greater goblet cell density and mucin volume density compared to COPD subjects. Here, MUC5AC is linked to chronic obstructive pulmonary disease.