Global epidemiological study of Down's syndrome

Abstract

Introduction: In 1967, the Latin American Collaborative Study of Congenital Malformations (LASCM) was created. Currently, 180 hospitals in 76 cities of 9 Latin American countries participate, accumulating data from over 4.5 M births. The Clinical Hospital of the University of Chile (HCUCH) entered the study in 1967, as did 12 other institutions later on. 

Objectives: Verify changes (increase) in frequency of Down's Syndrome (DS) in Chile and Latin America, and modification of frequency in those countries where elective abortion is permitted. 

Patients y Method: Three samples were evaluated: Births at HCUCH, active chilean hospitals and the 180 hospitals in 9 LA countries between 1972 and 2009. DS frequencies in Chile and other countries were compared through the International Clearinghouse for Birth Defects Monitoring System. 

Results: DS frequency at HCUCH increased significantly from 1.03 per thousand births in 1972 to 2.93 /^oo births 2009. Frequencies in all chilean hospitals are fairly homogeneous, all higher than average for LASCM, which is 1.88 per thousand. The chilean average is 2.47/°° por the period between 1998-2005, with a range of 1.88 at HCUCH to 2.86 at the Hospital of Curicó. In the rest of the world, the rate of DS per birth has diminished significantly, being the lowest in Iran (0.32/^o<>) and Spain (0.6/oo live births). 

Conclusion: Rate of DS births are higher in Chile than LASCM average (2.47/^o<>), with a trend to increase. This is true in Latin America, where the average for the period between 2001-2005 was 2.89 per thousand live births. In Europe and Asia, these rates have decreased to very low numbers, such as 0.32/^o<> in Iran and 0.6/^o<> in Spain.