1. Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland
2. Department of Obstetrics and Gynecology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
3. Faculty of Social Science, University of Tampere, Tampere, Finland
4. Department of Public Health, School of Medicine, University of Helsinki, Helsinki, Finland
5. Information Services Department, Finnish Institute for Health and Welfare, Helsinki, Finland
6. Department of Neurobiology, Care Science and Society, Karolinska Institute, Stockholm, Sweden
7. Dana Farber Cancer Institute/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA, USA
8. Department of Pediatrics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland