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



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.


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.


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.


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

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Corresponding author

Correspondence to Melih Cayonu.

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The authors declare that they have no conflict of interest.

Ethical approval

All procedures in this study involving human participants were performed in accordance with the ethical standards of the institutional research committee (Ankara Numune Training and Research Hospital, IRB No. E-18-1835) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

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Informed consent was obtained from all individual participants included in the study.

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Dinc, A.S., Cayonu, M., Duyar, S.S. et al. Increased age adversely affects the therapeutic effect of CPAP treatment for olfactory functions. Sleep Breath 24, 83–88 (2020).

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  • Obstructive sleep apnoea
  • Olfaction disorders
  • Nasal continuous positive airway pressure
  • Polysomnography