Epidemiology of Down syndrome

In literature the ratio of Down Syndrome (DS) newborns is usually 1:1,000. A lot of papers relate none differences about geographical distribution or differences for race. Instead there are many researches about the epidemiology of DS in different countries. Aim of this research is to make an up-to-date picture about the distribution of DS people. A meta-analysis was performed in pubmed by the keywords: Down Syndrome, epidemiology, ratio, newborn, prevalence, mortality. Moreover we analysed the data of the European of Congenital Anomalies and Twins (EUROCAT) and the data of the International Clearinghouse for Birth Defect Monitoring System (ICBDMS). The newborn ratio is correlated with the laws and the customs about abortion: for example in Ireland and in United Arab Emirates the prevalence of DS is higher than in France. Moreover the choice of abortion is different around the world: in Australia the ratio of abortion is lower than in USA. In the period 2001-2005, the ratio of newborn with DS in Europe was between 3:10,000 and 26:10,000. The trend of this ratio was decreasing or constant during the time because of the recourse to abortion, only in Canada the trend is creasing. Also the risk of a DS pregnancy changes with race: infants of Hispanic mothers, compared with infants of non-Hispanic white mothers, had a significantly higher birth prevalence of DS. It is very important that every countries create a registry for controlling the prevalence of DS people in order to give them the suitable resources and structures.