Causes of death in patients with Down syndrome in 2014-2016: A population study in Japan.

Despite the higher mortality rates in patients with Down syndrome compared with the general Japanese population, the life span has dramatically increased in Japan and other countries. We aimed to clarify recent causes of death in patients with Down syndrome in Japan. We calculated proportionate mortality and standardized mortality odds ratios (SMORs) among all deaths registered with Down syndrome as the cause of death (ICD-10 code, Q90) in the Japanese National Death Registry Database in 2014-2016. In the study period, 762 in patients with Down syndrome died. The main causes of death were pneumonia/respiratory infections (20.5%), congenital malformations of the circulatory system (11.2%), other diseases of the circulatory system (9.2%), and aspiration pneumonia (8.4%). The SMORs (95% confidence intervals) were higher for natural death, defined as death of an elderly person with no other cause of death to be mentioned (55.73 [36.92-84.12]), early-onset Alzheimer's disease, defined as Alzheimer's disease with onset <65 years of age (29.36 [16.44-52.44]), aspiration pneumonia (18.33 [14.03-23.96]), pneumonia/respiratory infections (8.11 [6.76-9.73]), congenital malformations of the circulatory system (8.07 [5.98-10.88]), and leukemia/lymphoma (2.16 [1.55-2.99]) but lower for malignant solid tumors (0.04 [0.02-0.06]) in patients with Down syndrome. Patients with Down syndrome had the greatest relative risk of dying from natural death, early-onset Alzheimer's disease, and respiratory illnesses, highlighting the need for appropriate medical, health, and welfare services.

Secular trends in longevity among people with Down syndrome in Japan, 1995-2016.

BACKGROUND: Life expectancy in Japan has increased dramatically and is one of the longest in the world. However, the changes in lifespan in Japanese individuals with congenital diseases remain unknown. We investigated secular changes in the lifespan of people with Down syndrome over the last 20 years. METHODS: We observed secular trends in the number of stillbirths, deaths and the mortality rates at ages 20, 40, and 60 among all deaths registered with Down syndrome as the cause of death (ICD10 code: Q90) in the Japan national death registry database between 1995 and 2016. Changes in the median age at death between 1995-2005 and 2006-2016 were investigated based on sex and history of surgery. RESULTS: We identified 240 stillbirths and 1,099 deaths in this period. The annual number of stillbirths and deaths above the age of 1 year increased, whereas the number of deaths below 1 year did not change. The proportional mortality indicator at ages 20, 40, and 60 increased from 21.7%, 11.7%, and 1.7% in 1995 to 69.9%, 66.7%, and 36.6% in 2016, respectively. The median age at death was higher in females, individuals without a surgical history, and deaths occurring in 2006-2016. The median age at death increased over the period in those without a surgical history. CONCLUSIONS: The age at death among people with Down syndrome has increased over the last 20 years, with currently 1 in 3 persons living over 60 years, necessitating adequate social welfare services in this aging population.