1. Department of Clinical and Molecular Medicine; Norwegian University of Science and Technology; Trondheim Norway
2. Department of Public Health and Nursing; Norwegian University of Science and Technology; Trondheim Norway
3. Department of Physiotherapy; Trondheim Municipality; Trondheim Norway
4. Department of Public Health Solutions; National Institute for Health and Welfare; Oulu and Helsinki Finland
5. Institute of Health Sciences; University of Oulu; Oulu Finland
6. Department of Psychology and Logopedics; University of Helsinki; Helsinki Finland
7. Department of Nursing Science; University of Turku; Turku Finland
8. PEDEGO Research Unit (Research Unit for Pediatrics; Dermatology, Clinical Genetics, Obstetrics and Gynecology); Medical Research Center Oulu (MRC Oulu); Oulu University Hospital and University of Oulu; Oulu Finland
9. Children's Hospital; Helsinki University Central Hospital and University of Helsinki; Helsinki Finland
10. Department of Psychology; University of Warwick; Coventry UK
11. Department of General Practice and Primary Health Care; University of Helsinki and Helsinki University Hospital; Helsinki Finland
12. Folkhälsan Research Center; Helsinki Finland
13. Department of Epidemiology and Biostatistics; Imperial College; London UK