Advances in the study of mechanisms underlying olfactory dysfunction in obstructive sleep apnea:a narrative review

Obstructive sleep apnea (OSA) and olfactory dysfunction have a reciprocal relationship, where each condition exacerbates the other. This review aims to systematically explore the key mechanisms underlying the association between OSA and olfactory impairment, offering a detailed analysis of these interrelated phenomena. A comprehensive literature search was conducted on PubMed/MEDLINE in October 2024, focusing on studies published in the last decade that investigate the link between OSA and olfactory dysfunction. The search included various types of research, such as review articles, experimental studies, and clinical trials, which examine the interplay between OSA, sleep disturbances, intermittent hypoxia, and olfactory dysfunction. Literature analysis indicates that oxidative stress, inflammatory responses, central nervous system damage, and nasal airflow obstruction caused by OSA are the primary causes of olfactory dysfunction. Furthermore, these mechanisms exhibit complex interactions, suggesting a multifactorial etiology in which both peripheral and central factors contribute to olfactory impairment. There is a strong association between OSA and olfactory dysfunction. However, current research predominantly focuses on basic experimental findings, with a noticeable lack of robust clinical trial evidence. Future research should prioritize clinical investigations to further validate these mechanisms and guide the development of targeted therapeutic interventions.