1. Dept. of Child Neurology, University of Turku, Finland, Public Health Center, Turku, Finland, Dept. of Public Health, University of Turku, Lcmminkaisenkatu 1, 20520 Turku, Finland
2. Dept. of Public Health, University of Turku, Lcmminkaisenkatu 1, 20520 Turku, Finland
3. Dept. of Child Neurology, University of Turku, Finland
4. Public Health Center, Turku, Finland