Changes in mortality and causes of death in the Swedish Down syndrome population

Abstract

During the past few decades age at death for individuals with Down syndrome (DS) has increased dramatically. The birth frequency of infants with DS has long been constant in Sweden. Thus, the prevalence of DS in the population is increasing. The aim of the present study was to analyze mortality and causes of death in individuals with DS during the period 1969-2003. All individuals with DS that died between 1969 and 2003 in Sweden, and all individuals born with DS in Sweden between 1974 and 2003 were included. Data were obtained from the Swedish Medical Birth Register, the Swedish Birth Defects Register, and the National Cause of Death Register. Median age at death has increased by 1.8 years per year. The main cause of death was pneumonia. Death from congenital heart defects decreased. Death from atherosclerosis was rare but more frequent than reported previously. Dementia was not reported in any subjects with DS before 40 years of age, but was a main or contributing cause of death in 30% of the older subjects. Except for childhood leukemia, cancer as a cause of death was rare in all age groups. Mortality in DS, particularly infant mortality, has decreased markedly during the past decades. Median age at death is increasing and is now almost 60 years. Death from cancer is rare in DS, but death from dementia is common.

What people with Down Syndrome can teach us about cardiopulmonary disease

“…Respiratory disease accounts for 43-78% of intensive care unit admissions, and 50% of those required ventilation support [12,36,37]. Respiratory illness is second only to CHD in mortality of individuals with Down syndrome at any age [38]. The average hospital stay due to lower respiratory illness is longer for children with Down syndrome [11].…”

“…For persons with Down syndrome aged <3 years, respiratory illnesses are the most common cause of hospital admissions [165], and respiratory disease is by far the most common cause of death in persons with Down syndrome [38]. Both intrinsic immune defects and extrinsic (anatomical) factors contribute to disturbed immune function and respiratory infection in individuals with Down syndrome [166][167][168].…”

Trends in Congenital Heart Defects in Infants With Down Syndrome

“…3,6 Approximately half of infants with Down syndrome are diagnosed with congenital heart defects, compared with a baseline risk of ∼1%. 7,8 Related complications, such as pulmonary hypertension and heart failure may affect health and survival, 9 but a change in attitudes toward treatment of infants with Down syndrome, corrective heart surgery included, has improved prognosis. 10,11 For example, the infant mortality rate among infants with Down syndrome in Sweden has decreased from 41% during 1969 to 1973 to 4% during 1999 to 2003.…”

“…10,11 For example, the infant mortality rate among infants with Down syndrome in Sweden has decreased from 41% during 1969 to 1973 to 4% during 1999 to 2003. 9 Recent studies from Norway and Canada have demonstrated small declines in the incidence of congenital heart defects over time in the general population. 7,12 Improved diagnostic tools like fetal echocardiography may have led to more pregnancy terminations when severe malformations are diagnosed antenatally.…”

Leukemogenesis in Down syndrome

“…While the hematological abnormalities observed in newborns and infants with DS vary case by case, the following abnormalities are often observed: macrocytosis, neutrophilia, thrombocytopenia, and polycythemia [28][29][30]. In contrast to the high risk of leukemias in the pediatric period, leukemias are no longer a common cause of death in adults with DS [31]. Instead, macrocytosis and leucopenia are often observed in adult DS cases, leading to the early onset of myelodysplastic syndrome and bone marrow failure [32].…”