1. Department of Paediatrics and Adolescent Medicine Turku University Hospital Turku Finland
2. University of Turku Turku Finland
3. Department of Paediatric Neurology University of Turku Turku Finland
4. Université Paris Cité, Inserm, INRAE, Centre of Research in Epidemiology and Statistic (CRESS) Paris France
5. Department of Biostatistics University of Turku and Turku University Hospital Turku Finland
6. Department of Mathematics and Statistics University of Vaasa, Finland Vaasa Finland