The authors declare that they have no competing interests.
RTW and CBP acquired the data for the study. RTW, CBP, PLHM and SA contributed to the study concept and design. SA carried out the statistical analyses. All authors contributed to the interpretation of data. PLHM, RTW and CBP drafted the manuscript. All authors critically revised the manuscript for important intellectual content. CBP and SA had full access to all the data in the study and take full responsibility for the integrity of the data and accuracy of the data analysis. All authors read and approved the final manuscript.
PLHM, PhD, is a research associate based in the Centre for Mental Health and Safety, University of Manchester, England. She has a broad research interests in the area of mental health and is currently working on a project investigating the determinants of suicidal behaviour, premature mortality, violence, and other adverse outcomes in young people.
SA, MSc, is a statistician at the Centre for Integrated Register-based Research, and the National Centre for Register-Based Research, Aarhus University, Denmark.
CBP, DrMedSc, is professor of register-based research at the Centre for Integrated Register-based Research, and the National Centre for Register-Based Research, Aarhus University, Denmark. He has conducted numerous register-based studies in the field of psychiatric epidemiology, with a particular focus on the aetiology of schizophrenia and other forms of severe mental illness.
LA, MD, is professor of psychiatry based in the Centre for Mental Health and Safety, University of Manchester, England. He is National Director for Health and Criminal Justice and, since 1996, has also led the National Confidential Inquiry into Suicide and Homicide by People with Mental Illness.
JW, PhD, is professor of forensic psychiatry based in the Centre for Mental Health and Safety, University of Manchester, England. Her research interests include violence, homicide, and suicide. As head of the Offender Health Research Network she leads numerous epidemiological and health services research studies in prisons and other forensic psychiatric settings.
RTW, PhD, is a reader in mental health epidemiology based in the Centre for Mental Health and Safety, University of Manchester, England. He has broad research interests that cover various aspects of psychiatric epidemiology, particularly the determinants of suicidal behaviour, premature mortality, violence, and other adverse outcomes in young people.
Psychiatric illness, substance misuse, suicidality, criminality and premature death represent major public health challenges that afflict a sizeable proportion of young people. However, studies of multiple adverse outcomes in the same cohort at risk are rare. In a national Danish cohort we estimated sex- and age-specific incidence rates and absolute risks of these outcomes between adolescence and early middle age.
Using interlinked registers, persons born in Denmark 1966–1996 were followed from their 15th until 40th birthday or December 2011 (N = 2,070,904). We estimated sex- and age-specific incidence rates of nine adverse outcomes, in three main categories: Premature mortality (all-causes, suicide, accident); Psychiatric morbidity (any mental illness diagnosis, suicide attempt, alcohol or drug misuse disorder); Criminality (violent offending, receiving custodial sentence, driving under influence of alcohol or drugs). Cumulative incidences were also calculated using competing risk survival analyses.
For cohort members alive on their 15th birthday, the absolute risks of dying by age 40 were 1.99 % for males [95 % confidence interval (CI) 1.95–2.03 %] and 0.85 % for females (95 % CI 0.83–0.88 %). The risks of substance misuse and criminality were also much higher for males, especially younger males, than for females. Specifically, the risk of a first conviction for a violent offence was highest amongst males aged below 20. Females, however, were more likely than males to have a hospital-treated psychiatric disorder. By age 40, 13.25 % of females (95 % CI 13.16–13.33 %) and 9.98 % of males (95 % CI 9.91–10.06 %) had been treated. Women aged below 25 were also more likely than men to first attempt suicide, but this pattern was reversed beyond this age. The greatest gender differentials in incidence rates were in criminality outcomes.
This is the first comprehensive assessment of the incidence rates and absolute risks of these multiple adverse outcomes. Approximately 1 in 50 males and 1 in 120 females who are alive on their 15th birthday will die by age 40. By examining the same cohort at risk, we compared risks for multiple outcomes without differential inter-cohort biases. These epidemiological profiles will inform further research into the pathways leading to these adverse events and future preventive strategies.