1. Sant Pau Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
2. Center of Biomedical Investigation Network for Neurodegenerative Diseases, Madrid, Spain
3. National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
4. Departments of Pediatrics and Obstetrics and Gynecology, University of Florida College of Medicine, Gainesville, Florida
5. Department of Epidemiology, University of Florida College of Public Health and Health Professions and College of Medicine, Gainesville, Florida
6. Iberoamerican Cochrane Centre, Biomedical Research Institute Sant Pau, Barcelona, Spain
7. Barcelona Down Medical Center, Fundació Catalana Síndrome de Down, Barcelona, Spain