Mortality rate and cause among people with intellectual disabilities in South Korea: A nationwide representative cross-sectional study from 2015 to 2019

People with intellectual disabilities (ID) age faster and have a higher prevalence of degenerative diseases. The aim of this study was to identify the patterns/ causes of death among people with ID. We conducted a nationwide, retrospective, cross-sectional study of people with ID in South Korea. The database was compiled by merging data of people registered with ID, based on the 2015–2019 Standards from the Ministry of Health and Welfare, with the cause of death data published by the Korea National Statistical Office. The International Classification of Diseases-10 (ICD-10) was used to categorize causes of death. The mortality and standardized mortality rates were calculated and major causes of death were analyzed. As of 2019, the mortality rate of people with ID in South Korea was 784.6. The rate showed an irregular pattern, increasing or decreasing year by year (increasing from 725 in 2015 to 834 in 2018). The mortality rate of people with ID was approximately 1.4 times higher than the general population; the standardized mortality rate was 3.2 times higher. The main causes of death (48%) in people with ID were, in order of prevalence, circulatory diseases (cerebrovascular disease), neoplasms (malignant neoplasms of the digestive system), and diseases of the respiratory system (pneumonia). The leading causes of death (>60%) in the general population were, in order of prevalence, neoplasms, diseases of the circulatory system, and respiratory system diseases. An accurate understanding of the causes of death of people with ID is important to promote the development and application of health promotion programs and management thereof.