Increased age adversely affects the therapeutic effect of CPAP treatment for olfactory functions.

Purpose: The aim of this study was to compare olfactory functions pre- and post-CPAP treatment in patients with moderate to severe OSA, and to evaluate the factors that cause changes in olfactory functions.

Methods: Twenty-two patients who had completed regular usage of CPAP treatment for 2 months were included in this prospective study. Olfactory tests using Sniffin' Sticks were performed pre- and post-treatment.

Results: The mean age of the subjects was 47.6 ± 9.5 years. We did not find a significant change in olfactory functions after 2 months of CPAP treatment in our study group. When the patients were divided into two groups-those whose olfactory functions showed improvement and those whose functions did not-it was found that the mean age of the patients whose olfactory functions did not improve was significantly higher statistically. A significant adverse correlation was found between age and post-treatment olfactory functions, specifically in odour threshold and odour identification scores.

Conclusions: Increased age adversely affects the therapeutic effect of CPAP treatment for olfactory functions.