Prevalence and incidence of vitiligo and associated comorbidities: a nationwide population-based study in Korea

BACKGROUND: The prevalence of vitiligo shows regional variance. Recently, an association between vitiligo and extracutaneous conditions including other autoimmune, metabolic and dermatological disorders has been suggested. Despite its increasing incidence, the epidemiological trends and comorbidities in people with vitiligo have rarely been quantified in Asia. AIM: To determine the prevalence and incidence of vitiligo and the disorders associated with vitiligo using the National Health Insurance Service database. METHODS: We included all patients with vitiligo, classified by the International Classification of Disease, 10th revision (ICD-10) code of L80, with ≥ 3 documented visits from 2003 to 2019. The incidence and prevalence of vitiligo were estimated for the study period. Age-, sex-, insurance type- and income level-matched controls (ratio 1 : 5) were selected to compare comorbidities. The odds ratios between comorbidities and vitiligo were calculated through conditional logistic regression. RESULTS: The incidence and annual prevalence of vitiligo in Korea increased from 2003 to 2019, with incidence peaking in summer. Age-specific incidence showed a bimodal distribution, with the steepest increase in the group aged < 20 years. Many comorbidities, including alopecia areata, psoriasis, rheumatoid arthritis, systemic lupus erythematosus, Crohn disease, ulcerative colitis, Sjögren syndrome, diabetes mellitus, dyslipidaemia, chronic hepatitis, anxiety disorder and mood disorder showed higher odds ratios in patients with vitiligo than controls. CONCLUSION: The incidence and prevalence of vitiligo are increasing, particularly among younger patients in Korea. In addition, various comorbidities are associated with vitiligo, therefore, if patients with vitiligo present with extracutaneous symptoms, physicians should consider the possibility of other comorbid diseases.