Epidemiology of Anosmia in South Korea: A Nationwide Population-Based Study.

Research about the epidemiology of olfactory dysfunction in Asians was not enough. The purpose of this study was to assess the prevalence and incidence rate of olfactory disorders in Koreans and to evaluate demographic risk factors. We analyzed clinical data of patients with anosmia using Korean National Health Insurance Service data from 2006 to 2016. The data includes medical insurance claim data and medical records of almost 50,000,000 people in Korea. The 30-39 age group showed the highest prevalence (19.25 per 10,000 per year). Their incidence rate was also high comparing other age groups (13.30 per 10,000 per year). The prevalence and the incidence increased from 7.10 to 13.74 and from 5.66 to 9.54 between 2006 and 2016. In the seasonal analysis, the incidence rate was high in spring and autumn. The high-income population showed about 1.4-folds higher incidence rate than the low-income population. We thought that the socioeconomic status could generally affect the rate of hospital visit in the anosmia population. Anosmia can be frequently underdiagnosed in the clinical environment because the elderly and the low-income people easily underestimate their anosmia symptom and ignore the severity due to their economic problem. Therefore careful attention and further studies for anosmia are needed.