Global Trends in the Incidence, Prevalence and Disability-Adjusted Life Years of Leprosy from 1990 to 2019: An Age-Period-Cohort Analysis Using the Global Burden of Disease Study 2019.

Background: Leprosy is a neglected tropical disease, with approximately 200,000 new cases reported worldwide every year. Although there are numerous studies on the epidemiology of leprosy, the age, period, and cohort effects remain poorly understood. Objective: We present an overview of trends in leprosy incidence, prevalence and disability-adjusted life years worldwide from 1990 to 2019 and associations with age, period, and birth cohort. Data for analysis were obtained from the Global Burden of Disease Study 2019. Methods: We described incident case, prevalent case, age-standardised incidence, prevalence and disability-adjusted life years rates of leprosy from 1990 to 2019. Subsequently, we calculated overall annual percentage changes, annual percentage changes, and the relative risks of period and cohort using an age-period-cohort model. Results: From 1990 to 2019, the global age-standardized incidence rate of leprosy decreased from 1.48 per 100,000 to 0.65 per 100,000. Additionally, countries with low Socio-Demographic Index ( Conclusion: Leprosy incidence, prevalence and disability-adjusted life years have significantly decreased globally, but remain high in areas with lower SDI. Developing regions should increase public awareness of leprosy risk factors, develop effective control policies to better manage and prevent the disease.