The nature and extent of child maltreatment in Denmark:Using self-report and administrative data from the 1984 birth cohort

Background: Research on child maltreatment (CM) has few longitudinal studies that combine self-report data with objective administrative data that has been collected continuously for decades. Objective: To give an overview of 20 studies investigating the impact of CM in a Danish representative sample. Participants and setting: From the full 1984 Danish birth cohort, 2980 24-years old were randomly selected. There was an oversampling of child protection cases. Methods: The participants were interviewed by trained interviewers and Computer Assisting Methods were used for sensitive topics. The survey data were linked to several national registers using the Civil Registry Number for a series of studies on risk factors and outcomes. Linkage with parental data enabled parental risk factors before the birth to be analysed as well as several physical, psychological, and social events during their lifetime. These factors were studied in relation to the CM classes that were identified via the survey. Results: The maltreatment classes had both several specific and shared effects pertaining to risk factors before birth, during childhood through to early adulthood. Their problems included many arenas within health, mental and social life. Conclusions: Data linkage studies provide an opportunity to conduct research using accurate sources of information which can be used to explore risk and protective factors. The prospective nature of this combined data facilitates temporal ordering which strengthen the conclusions based on longer-term follow-up.