Figure 2. Histological changes in the lamina propria of the upper airway mucosa in OSAS patients according to smoking history.

Lamina propria thickness increased with longer smoking duration. The most severe thickening of the lamina propria was observed in the upper airway mucosa of smokers with a history of over 10 PY. (A) Nonsmoker, (B) < 10 pack years, (C) > 10 pack years (H – E, × 40).