Prevalence of onychomycosis in Korea: A nationwide population-based study

Background: Onychomycosis is a common fungal infection of the toenails and fingernails. Although onychomycosis is a common health concern, there is a lack of nationwide studies of this condition in Korea. Objective: We aimed to investigate the prevalence of onychomycosis according to age, month of hospital visit, and residence using national statistics provided by the National Health Insurance Service (NHIS) of South Korea in 2015. Methods: We utilized data from the NHIS database that was procured between January and December, 2015. Statistical analyses were performed using the SAS version 9.4 (SAS Institute, Cary, NC, USA). Results: The prevalence of onychomycosis was 3.49%. Its prevalence among individuals in their 60s (OR 5.148, 95%CI of 5.113∼5.183) and 70s (OR 5.466, 95%CI of 5.427∼5.505) was significantly higher than that of those in their 20s (reference age group). The highest prevalence of onychomycosis was observed in summer. The age-standardized prevalence ranged from 3.24% to 4.29% based on the place of residence, with the highest prevalence observed in provinces and large cities at lower latitudes, including Jeollanam-do, Gyeongsangnam-do, Ulsan, and Jeju-do. Conclusion: This is the first nationwide study exploring the prevalence of onychomycosis in Korea according to the place of residence. The prevalence of onychomycosis primarily depends on age and region.