Henrik Daae Zachrisson

Academic interests
Substantive
- Early Childhood Education and Care
- Social inequality in early education
- Consequences of childhood poverty
Methodological
- Causal modeling in observational data
- Measurement of change
- Measurement models in early childhood
Teaching
I'm teaching mainly on SPED2100 (developmental psych for BA) and SPED4010 (methods for MA) this fall
Past teaching:
SPED1200: Research methods and research based practice in special needs education
SPED2100: Theories of child development and social development
SPED4010: Quantitative methods
UV9255 Causal modelling in non-experimental data
see http://www.uio.no/studier/emner/uv/uv/UV9255/index-eng.html
With Ronny Scherer: Learn to write empirical research paper
Background
- Psychologist, University of Aarhus, Denmark
- PhD, Department of Psychology at UiO in 2009
- PhD fellow and later Post Doc fellow at the Norwegian Institute of Public Health.
- Senior Researcher, The Norwegian Center for Child Behavioral Development (www.nubu.no)
- Professor II, Center for Educational Measurement at the University of Oslo
Publications
- Nordahl, Kristin B.; Owen, Margaret Tresch; Ribeiro, Luisa Jacinta Feio Antunes & Zachrisson, Henrik Daae (2020). Parenting quality from observational ratings at age 2: validation from Norwegian and U.S. Samples. Early Childhood Research Quarterly. ISSN 0885-2006. 53(4), s 379- 390 . doi: 10.1016/j.ecresq.2020.05.010
- Ribeiro, Luisa Jacinta Feio Antunes; Casey, Beth; Dearing, Eric Curtis; Nordahl, Kristin B.; Aguiar, Cecilia & Zachrisson, Henrik Daae (2020). Early Maternal Spatial Support for Toddlers and Math Skills in Second Grade. Journal of Cognition and Development. ISSN 1524-8372. 21(2), s 282- 311 . doi: 10.1080/15248372.2020.1717494
- Strietholt, Rolf; Hogrebe, Nina & Zachrisson, Henrik Daae (2020). Do increases in national-level preschool enrollment increase student achievement? Evidence from international assessments. International Journal of Educational Development. ISSN 0738-0593. . doi: 10.1016/j.ijedudev.2020.102287 Full text in Research Archive.
- Torvik, Fartein Ask; Eilertsen, Espen Moen; McAdams, Tom A.; Gustavson, Kristin; Zachrisson, Henrik Daae; Brandlistuen, Ragnhild Eek; Gjerde, Line C.; Havdahl, Alexandra; Stoltenberg, Camilla; Ask, Helga & Ystrøm, Eivind (2020). Mechanisms linking parental educational attainment with child ADHD, depression, and academic problems: a study of extended families in The Norwegian Mother, Father and Child Cohort Study. Journal of Child Psychology and Psychiatry. ISSN 0021-9630. 61(9), s 1009- 1018 . doi: 10.1111/jcpp.13197 Full text in Research Archive.
- Zachrisson, Henrik Daae; Owen, Margaret T.; Nordahl, Kristin B.; Ribeiro, Luisa & Dearing, Eric (2020). Too Early for Early Education? Effects on Parenting for Mothers and Fathers. Journal of Marriage and Family. ISSN 0022-2445. . doi: 10.1111/jomf.12701 Full text in Research Archive.
- Dearing, Eric Curtis & Zachrisson, Henrik Daae (2019). Taking Selection Seriously in Correlational Studies of Child Development: A Call for Sensitivity Analyses. Child Development Perspectives. ISSN 1750-8592. . doi: 10.1111/cdep.12343 Full text in Research Archive. Show summary
- Feyer, Frida Karine & Zachrisson, Henrik Daae (2019). Country Reports: Norway, In Joana Guerra; Catarina Leitão & Clara Barata (ed.), Interview study of service providers and coordinators on interagency coordination for children and families. Policies and practices in nine European countries. ISOTIS D6.3 Report. Inclusive Education and Social Support to Tackle Inequalities in Society. Part B. Country Reports: Norway. s 100 - 112
- Ribeiro, Luisa Jacinta Feio Antunes & Zachrisson, Henrik Daae (2019). Peer Effects on Aggressive Behavior in Norwegian Child Care Centers. Child Development. ISSN 0009-3920. 90(3), s 876- 893 . doi: 10.1111/cdev.12953 Full text in Research Archive.
- Zachrisson, Henrik Daae; Janson, Harald & Lamer, Kari (2019). The Lamer Social Competence in Preschool (LSCIP) Scale: Structural Validity in a Large Norwegian Community Sample. Scandinavian Journal of Educational Research. ISSN 0031-3831. 63(4), s 551- 565 . doi: 10.1080/00313831.2017.1415963 Full text in Research Archive.
- Zambrana, Imac Maria; Ogden, Terje & Zachrisson, Henrik Daae (2019). Can Pre-Academic Activities in Norway’s Early Childhood Education and Care Program Boost Later Academic Achievements in Preschoolers at Risk?. Scandinavian Journal of Educational Research. ISSN 0031-3831. . doi: 10.1080/00313831.2019.1577751 Full text in Research Archive.
- Cook, Kyle DeMeo; Dearing, Eric & Zachrisson, Henrik Daae (2018). Is Parent-Teacher Cooperation in the First Year of School Associated with Children's Academic Skills and Behavioral Functioning?. International Journal of Early Childhood. ISSN 0020-7187. 50(2), s 211- 226 . doi: 10.1007/s13158-018-0222-z Full text in Research Archive.
- Dearing, Eric; Zachrisson, Henrik Daae; Mykletun, Arnstein & Toppelberg, Claudio O (2018). Estimating the Consequences of Norway’s National Scale-Up of Early Childhood Education and Care (Beginning in Infancy) for Early Language Skills. AERA Open. ISSN 2332-8584. 4(1), s 1- 16 . doi: 10.1177/2332858418756598 Full text in Research Archive.
- Eliassen, Erik; Zachrisson, Henrik Daae & Melhuish, Edward (2018). Is cognitive development at three years of age associated with ECEC quality in Norway?. European Early Childhood Education Research Journal. ISSN 1350-293X. 26(1), s 97- 110 . doi: 10.1080/1350293X.2018.1412050 Full text in Research Archive.
- Kjøbli, John; Zachrisson, Henrik Daae & Bjørnebekk, Gunnar (2018). Three Randomized Effectiveness Trials — One Question: Can Callous-Unemotional Traits in Children Be Altered?. Journal of Clinical Child & Adolescent Psychology. ISSN 1537-4416. 47(3), s 436- 443 . doi: 10.1080/15374416.2016.1178123 Full text in Research Archive.
- Bøe, Tormod; Dearing, Eric; Stormark, Kjell Morten & Zachrisson, Henrik Daae (2017). Subjective economic status in adolescence: determinants and associations with mental health in the Norwegian Youth@ Hordaland Study. Journal of Family and Economic Issues. ISSN 1058-0476. Published ahead of print, s 1- 14 . doi: 10.1007/s10834-017-9553-4 Full text in Research Archive.
- Bøe, Tormod; Skogen, Jens Christoffer; Sivertsen, Børge; Hysing, Mari; Petrie, Keith James; Dearing, Eric & Zachrisson, Henrik Daae (2017). Economic volatility in childhood and subsequent adolescent mental health problems: a longitudinal populationbased study of adolescents. BMJ Open. ISSN 2044-6055. 7(9) . doi: 10.1136/bmjopen-2017-017030 Full text in Research Archive.
- Cook, Kyle DeMeo; Dearing, Eric & Zachrisson, Henrik Daae (2017). Information Sharing between Teachers and Early Education Programs during School Entry in Norway: Associations with Children's School Adjustment and Success in the First Year. International Journal of Child Care and Education Policy. ISSN 1976-5681. 11(14) . doi: 10.1186/s40723-017-0039-5 Full text in Research Archive.
- Dearing, Eric & Zachrisson, Henrik Daae (2017). Concern Over Internal, External, and Incidence Validity in Studies of Child-Care Quantity and Externalizing Behavior Problems. Child Development Perspectives. ISSN 1750-8592. 11(2), s 133- 138 . doi: 10.1111/cdep.12224 Full text in Research Archive.
- Feyer, Frida Karine & Zachrisson, Henrik Daae (2017). Country profile: Norway, In Joana Cadima; Gil Nata; Maria Evangelou & Yvonne Anders (ed.), Inventory and Analysis of Promising and Evidence-based Parent- and Family Focused Support Programs. ISOTIS report D3.2. Inclusive Education and Social Support to Tackle Inequalities in Society. 2.2.5. s 64 - 71
- Gjerde, Line C.; Eilertsen, Espen Moen; Reichborn-Kjennerud, Ted; McAdams, Tom A.; Zachrisson, Henrik Daae; Zambrana, Imac Maria; Røysamb, Espen; Kendler, Kenneth S. & Ystrøm, Eivind (2017). Maternal perinatal and concurrent depressive symptoms and child behavior problems: a sibling comparison study. Journal of Child Psychology and Psychiatry. ISSN 0021-9630. 58(7), s 779- 786 . doi: 10.1111/jcpp.12704 Full text in Research Archive.
- Lund, Terese J.; Dearing, Eric & Zachrisson, Henrik Daae (2017). Is affluence a risk for adolescents in Norway?. Journal of Research on Adolescence. ISSN 1050-8392. 27(3), s 628- 643 . doi: 10.1111/jora.12304 Full text in Research Archive.
- Petitclerc, Amelie; Côtè, Sylvana; Doyle, Orla; Burchinal, Margaret; Herba, Catherine; Zachrisson, Henrik Daae; Boivin, Michel; Tremblay, Richard E.; Tiemeier, Henning; Jaddoe, Vincent W. & Raat, Hein (2017). Who uses early childhood education and care services? Comparing socioeconomic selection across five western policy contexts. International Journal of Child Care and Education Policy. ISSN 1976-5681. 11(3) . doi: 10.1186/s40723-017-0028-8
- Ribeiro, Luisa A; Zachrisson, Henrik Daae & Dearing, Eric (2017). Peer effects on the development of language skills in Norwegian childcare centers. Early Childhood Research Quarterly. ISSN 0885-2006. 41, s 1- 12 . doi: 10.1016/j.ecresq.2017.05.003 Full text in Research Archive.
- Zachrisson, Henrik Daae; Dearing, Eric; Blömeke, Sigrid & Moser, Thomas (2017). What levels the playing field for socioeconomically disadvantaged children in the Norwegian ECEC model?, In Hans-Peter Blossfeld; Nevena Kulic; Jan Skopek & Moris Triventi (ed.), Childcare, Early Education and Social Inequality: An International Perspective. Edward Elgar Publishing. ISBN 9781786432087. 10. s 194 - 214
- Bøe, Tormod; Hysing, Mari & Zachrisson, Henrik Daae (2016). Low family income and behavior problems in Norwegian preschoolers: Is child emotionality a marker for sensitivity of influence?. Journal of Developmental and Behavioral Pediatrics. ISSN 0196-206X. 37(3), s 213- 222 . doi: 10.1097/DBP.0000000000000282
- Ribeiro, Luisa A; Zachrisson, Henrik Daae; Gustavson, Kristin & Schjølberg, Synnve (2016). Maternal distress during pregnancy and language development in preschool age: A population-based cohort study. European Journal of Developmental Psychology. ISSN 1740-5629. 13(1), s 20- 39 . doi: 10.1080/17405629.2015.1050373
- Dearing, Eric; Zachrisson, Henrik Daae & Nærde, Ane (2015). Age of Entry Into Early Childhood Education and Care as a Predictor of Aggression: Faint and Fading Associations for Young Norwegian Children. Psychological Science. ISSN 0956-7976. 26(10), s 1595- 1607 . doi: 10.1177/0956797615595011
- Sibley, Erin; Dearing, Eric; Toppelberg, Claudio O; Mykletun, Arnstein & Zachrisson, Henrik Daae (2015). Do increased availability and reduced cost of early childhood care and education narrow social inequality gaps in utilization? Evidence from Norway. International Journal of Child Care and Education Policy. ISSN 1976-5681. 9 . doi: 10.1007/s40723-014-0004-5
- Zachrisson, Henrik Daae & Dearing, Eric (2015). Family Income Dynamics, Early Childhood Education and Care, and Early Child Behavior Problems in Norway. Child Development. ISSN 0009-3920. 86(2), s 425- 440 . doi: 10.1111/cdev.12306
- Zambrana, Imac Maria; Dearing, Eric; Nærde, Ane & Zachrisson, Henrik Daae (2015). Time in early childhood education and care and language competence in Norwegian four-year-old girls and boys. European Early Childhood Education Research Journal. ISSN 1350-293X. 24(6), s 793- 806 . doi: 10.1080/1350293X.2015.1035538
- Alves, Daniele Evelin; Corliss, Heather L; Røysamb, Espen; Zachrisson, Henrik Daae; Oppedal, Brit & Gustavson, Kristin (2014). Immigrant Preadolescents and Risk of Emotional Distress. Scandinavian Journal of Child and Adolescent Psychiatry and Psychology. ISSN 2245-8875. 2(1), s 41- 51 . doi: 10.21307/sjcapp-2014-007 Full text in Research Archive.
- Alves, Daniele Evelin; Gustavson, Kristin; Røysamb, Espen; Oppedal, Brit & Zachrisson, Henrik Daae (2014). Preadolescents with immigrant backgrounds: the relationship between emotional problems, parental achievement values, and comparison. Scandinavian Journal of Child and Adolescent Psychiatry and Psychology. ISSN 2245-8875. 2(3), s 124- 134 . doi: 10.21307/sjcapp-2014-017 Full text in Research Archive.
- Nordahl, Kristin B.; Janson, Harald; Manger, Terje & Zachrisson, Henrik Daae (2014). Family concordance and gender differences in parent-child structured interaction at 12 months. Journal of Family Psychology. ISSN 0893-3200. 28(2), s 253- 259 . doi: 10.1037/a0035977
- Nærde, Ane; Ogden, Terje; Janson, Harald & Zachrisson, Henrik Daae (2014). Normative development of physical aggression from 8 to 26 months. Developmental Psychology. ISSN 0012-1649. 50(6), s 1710- 1720 . doi: 10.1037/a0036324
- Zachrisson, Henrik Daae; Dearing, Eric; Lekhal, Ratib & Toppelberg, Claudio O (2013). Little Evidence That Time in Child Care Causes Externalizing Problems During Early Childhood in Norway. Child Development. ISSN 0009-3920. 84(4), s 1152- 1170 . doi: 10.1111/cdev.12040
- Zachrisson, Henrik Daae; Janson, Harald & Nærde, Ane (2013). Predicting early center care utilization in a context of universal access. Early Childhood Research Quarterly. ISSN 0885-2006. 28(1), s 74- 82 . doi: 10.1016/j.ecresq.2012.06.004
- Alves, Daniele Evelin; Røysamb, Espen; Oppedal, Brit & Zachrisson, Henrik Daae (2011). Emotional problems in preadolescents in Norway: The role of gender, ethnic minority status, and home- and school-related hassles. Child and Adolescent Psychiatry and Mental Health (CAPMH). ISSN 1753-2000. 5 . doi: 10.1186/1753-2000-5-37
- Kvalbein, Luisa Ribeiro; Zachrisson, Henrik Daae; Schjølberg, Synnve; Aase, Heidi; Rohrer-Baumgartner, Nina Marit & Magnus, Per (2011). Attention problems and language development in preterm low-birth-weight children: Cross-lagged relations from 18 to 36 months. BMC Pediatrics. ISSN 1471-2431. 11 . doi: 10.1186/1471-2431-11-59
- Lekhal, Ratib; Zachrisson, Henrik Daae; Wang, Mari Vaage; Schjølberg, Synnve & Von Soest, Tilmann (2011). Does universally accessible child care protect children from late talking? Results from a Norwegian population-based prospective study. Early Child Development and Care. ISSN 0300-4430. 181(8), s 1007- 1019 . doi: 10.1080/03004430.2010.508558
- Schjølberg, Synnve; Eadie, Patricia; Zachrisson, Henrik Daae; Øyen, Anne-Siri & Prior, Margot (2011). Predicting language development at age 18 months: Data from the Norwegian Mother and Child Cohort Study. Journal of Developmental and Behavioral Pediatrics. ISSN 0196-206X. 32(5), s 375- 383 . doi: 10.1097/DBP.0b013e31821bd1dd
- Zachrisson, Henrik Daae; Lekhal, Ratib & Mykletun, Arnstein (2011). Hva gjør barnehagene med barna?. Tidsskrift for Norsk Psykologforening. ISSN 0332-6470. 48, s 578- 581
- Zachrisson, Henrik Daae; Røysamb, Espen; Oppedal, Brit & Hauser, Stuart T. (2011). Factor structure of the child attachment interview. European Journal of Developmental Psychology. ISSN 1740-5629. 8(6), s 744- 759 . doi: 10.1080/17405629.2011.631293
- Zachrisson, Henrik Daae; Sommerfeldt, Bente & Skårderud, Finn (2011). What you use decides what you get: Comparing classificatory procedures for the Adult Attachment Interview in eating disorder research. Eating and Weight Disorders. ISSN 1124-4909. 16(4), s E285- E288 . doi: 10.1007/bf03327474
- Zachrisson, Henrik Daae (2010). Tilknytning og psykisk helse hos sped- og småbarn, I: Vibeke Moe; Kari Slinning & Marit Bergum Hansen (red.), Håndbok i sped- og småbarns psykiske helse. Gyldendal Akademisk. ISBN 978-82-05-39071-3. Kapittel 14. s 285 - 298
- Zachrisson, Henrik Daae; Lekhal, Ratib & Schjølberg, Synnve (2010). Barnehage og psykisk helse hos sped- og småbarn, I: Vibeke Moe; Kari Slinning & Marit Bergum Hansen (red.), Håndbok i sped- og småbarns psykiske helse. Gyldendal Akademisk. ISBN 978-82-05-39071-3. Kapittel 39. s 770 - 783
- Zachrisson, Henrik Daae & Skårderud, Finn (2010). Feelings of insecurity: Review of attachment and eating disorders. European Eating Disorders Review. ISSN 1072-4133. 18(2), s 97- 106 . doi: 10.1002/erv.999
- Syed, Hammad Raza; Zachrisson, Henrik Daae; Dalgard, Odd Steffen; Dalen, Ingvild & Ahlberg, Nora (2008). Concordance between Hopkins Symptom Checklist (HSCL-10) and Pakistan Anxiety and Depression Questionnaire (PADQ), in a rural self-motivated population in Pakistan. BMC Psychiatry. ISSN 1471-244X. 8 . doi: 10.1186/1471-244X-8-59
- Zachrisson, Henrik Daae; Vedul-Kjelsås, Einar; Gøtestam, K Gunnar & Mykletun, Arnstein (2008). Time trends in obesity and eating disorders. International Journal of Eating Disorders. ISSN 0276-3478. 41(8), s 673- 680 . doi: 10.1002/eat.20565
- Zachrisson, Henrik Daae & Kulbotten, Gunhild R (2006). Attachment in anorexia nervosa: An exploration of associations with eating disorder psychopathology and psychiatric symptoms. Eating and Weight Disorders. ISSN 1124-4909. 11(4), s 163- 170
- Zachrisson, Henrik Daae; Rödje, Kjetil & Mykletun, Arnstein (2006). Utilization of health services in relation to mental health problems in adolescents: A population based survey. BMC Public Health. ISSN 1471-2458. 6 . doi: 10.1186/1471-2458-6-34
- Zachrisson, Anders & Zachrisson, Henrik Daae (2005). Validation of psychoanalytic theories. Towards a conceptualization of references. International Journal of Psychoanalysis. ISSN 0020-7578. 86(5), s 1353- 1371 . doi: 10.1516/FVGK-FJN3-V3D1-JRF8
- Zachrisson, Henrik Daae (2005). Stability and change in attachment patterns. Nordisk Psykologi: teori, forskning, praksis. ISSN 0029-1463. 57, s 303- 322
- Lekhal, Ratib; Zachrisson, Henrik Daae; Solheim, Elisabet; Moser, Thomas & Drugli, May Britt (2016). Barnehagen: Betydningen av kvalitet i barnehagen. Gyldendal Akademisk. ISBN 9788205495982. 88 s.
- Lekhal, Ratib; Zachrisson, Henrik Daae; Solheim, Elisabet; Moser, Thomas & Drugli, May Britt (2016). Det ved vi om: Betydningen af kvalitet i dagtilbud. Dafolo A/S. ISBN 9788771601671. 80 s.
- Alexandersen, Nina; Wilhelmsen, Tiril; Wang, Mari Vaage; Zachrisson, Henrik Daae & Brandlistuen, Ragnhild Eek (2019). Access to childcare quality in a universal context: the role of parental education and income.
- Moser, Thomas & Zachrisson, Henrik Daae (2019). Universal ECEC as a protective mean for children from disadvantaged families in Norway?.
- Eliassen, Erik & Zachrisson, Henrik Daae (2017). The causal effect of entry age on children's social competence at age 3 years.
- Zachrisson, Henrik Daae & Melhuish, Edward C. (2017). Early childhood education and care, In Brian Hopkins; Elena Geangu & Sally Linkenauger (ed.), The Cambridge Encyclopedia of Child Development. Cambridge University Press. ISBN 9781316216491. VI. s 459 - 463
- Zambrana, Imac Maria; Ogden, Terje & Zachrisson, Henrik Daae (2017). Can pre-academic activities in ECEC boost later academic achievements in preschoolers with externalizing behaviors?.
- Bøe, Tormod & Zachrisson, Henrik Daae (2016). Hva betyr det for barn å vokse opp i et fattig familie?, I: Hanne Holme; Ellen Solstad Olavesen; Lisbeth Valla & Marit Bergum Hansen (red.), Helsestasjonstjenesten: barns psykiske helse og utvikling. Gyldendal Norsk Forlag A/S. ISBN 9788205486294. Kapittel 13. s 161 - 171
- Zachrisson, Henrik Daae; Moser, Thomas; Blömeke, Sigrid & Dearing, Eric (2015). What levels the playing field in the Norwegian ECEC model? Evidence from the BONDS study on 2-4 years old children”.
- Hogsnes, Hilde Dehnes; Nærde, Ane & Zachrisson, Henrik Daae (2014). Barns sosiale utvikling – fra barnehage til skole..
- Zachrisson, Henrik Daae; Dearing, Eric; Zambrana, Imac Maria & Nærde, Ane (2014). Språkkompetanse hos 4-åringer som har gått i barnehage.
- Zachrisson, Henrik Daae; Moser, Thomas; Nærde, Ane & Dearing, Eric (2014). Sammenhengen mellom strukturelle kvalitetsindikatorer i barnehagen, og barns sosiale og faglige ferdigheter på første klassetrinn. Foreløpige resultater fra forskningsprosjektet Barns sosiale utvikling (Rapport til Utdanningsdirektoratet, 15.12.2014).
- Moser, Thomas; Zachrisson, Henrik Daae; Backer-Grøndahl, Agathe; Ogden, Terje & Nærde, Ane (2013). Small is beautiful? Peer group size, social competence and aggression in Norwegian ECEC.
- Moser, Thomas; Zachrisson, Henrik Daae; Nordahl, Kristin B. & Dearing, Eric (2013). Child care quality and language development.
- Dearing, Eric; Zachrisson, Henrik Daae & Mykletun, Arnstein (2011). Fattigdommens konsekvenser for utvikling og psykisk helse. Tidsskrift for Norsk Psykologforening. ISSN 0332-6470. 48(8), s 785- 787
- Zachrisson, Henrik Daae; Dearing, Eric; Toppelberg, Claudio O & Lekhal, Ratib (2011). Child Care Quantity and Early Childhood Aggression in a Large Norwegian Cohort..
- Alves, Daniele Evelin; Zachrisson, Henrik Daae; Oppedal, Brit & Røysamb, Espen (2009). Absence in gender differences in internalizing symptoms among ethnic minority preadolescents.
- Zachrisson, Henrik Daae (2009). Attachment in middle and late childhood : measurement validation and relation to mental health problems. Series of Dissertations submitted to the Faculty of Social Sciences, University of Oslo. No.167.
- Skårderud, Finn & Zachrisson, Henrik Daae (2008). Tilknytning og spiseforstyrrelser.
- Alves, Daniele Evelin; Zachrisson, Henrik Daae & Oppedal, Brit (2007). Validation of a short version of the Depression Experiences Questionnaire for Adolescents in a predominantly minority sample in Norway.
- Zachrisson, Anders & Zachrisson, Henrik Daae (2006). On: Validation of psychoanalytic theories: Toward a conceptualization of references - Response to Dr Torsti-Hagman. International Journal of Psychoanalysis. ISSN 0020-7578. 87
- Zachrisson, Henrik; Mykletun, Arnstein; Vedul-Kjelsås, Einar & Gøtestam, K Gunnar (2006). Forekomsten av spiseforstyrrelser blant kvinner med overvekt og fedme: en befolkningsbasert studie.