Chung HJ, Lim HS, Lee K, et al. - Researchers sought to assess the prevalence of clinically diagnosed olfactory dysfunction in South Korea by using well-organized, nationwide, population-based cohort data, and the relationships between olfactory dysfunction and risk of neurodegenerative disorders. They examined the Korean National Health Insurance Service–National Sample Cohort for patients diagnosed with olfactory dysfunction using the International Classification of Diseases. During the study period, 6,296 patients (524.67 patients/year) were clinically diagnosed with olfactory dysfunction. The prevalence increased year after year and was higher in female patients. Data reported that 4.2% of patients with olfactory dysfunction had neurodegenerative disorders during the study period. Diabetes mellitus and depression were found to be significant risk factors in a multivariate cox regression analysis of the patients. Olfactory dysfunction is underdiagnosed in South Korea, but it is clinically significant because it can be a precursor to neurodegenerative disorders. In clinical practice, its association with neurodegenerative disorders and possibly other systemic conditions should be considered.