1. Department of Social Statistics and Demography, University of Southampton, Southampton, UK;
2. Department of Public Health Solutions, National Institute for Health and Welfare (THL), Helsinki, Finland;
3. Information Services Department, National Institute for Health and Welfare (THL), Helsinki, Finland;
4. Research Centre for Child Psychiatry, University of Turku, Turku, Finland;
5. Department of Neurobiology, Care Services and Society, Karolinska Institute, Stockholm, Sweden;
6. Population Research Institute, Family Federation of Finland (Väestöliitto), Helsinki, Finland