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Abstract
Summary Background
Systematic reviews have consistently shown that individuals with mental disorders have an increased risk of premature mortality. Traditionally, this evidence has been based on relative risks or crude estimates of reduced life expectancy. The aim of this study was to compile a comprehensive analysis of mortality-related health metrics associated with mental disorders, including sex-specific and age-specific mortality rate ratios (MRRs) and life-years lost (LYLs), a measure that takes into account age of onset of the disorder.
MethodsIn this population-based cohort study, we included all people younger than 95 years of age who lived in Denmark at some point between Jan 1, 1995, and Dec 31, 2015. Information on mental disorders was obtained from the Danish Psychiatric Central Research Register and the date and cause of death was obtained from the Danish Register of Causes of Death. We classified mental disorders into ten groups and causes of death into 11 groups, which were further categorised into natural causes (deaths from diseases and medical conditions) and external causes (suicide, homicide, and accidents). For each specific mental disorder, we estimated MRRs using Poisson regression models, adjusting for sex, age, and calendar time, and excess LYLs (ie, difference in LYLs between people with a mental disorder and the general population) for all-cause mortality and for each specific cause of death.
Findings7 369 926 people were included in our analysis. We found that mortality rates were higher for people with a diagnosis of a mental disorder than for the general Danish population (28·70 deaths [95% CI 28·57–28·82] vs 12·95 deaths [12·93–12·98] per 1000 person-years). Additionally, all types of disorders were associated with higher mortality rates, with MRRs ranging from 1·92 (95% CI 1·91–1·94) for mood disorders to 3·91 (3·87–3·94) for substance use disorders. All types of mental disorders were associated with shorter life expectancies, with excess LYLs ranging from 5·42 years (95% CI 5·36–5·48) for organic disorders in females to 14·84 years (14·70–14·99) for substance use disorders in males. When we examined specific causes of death, we found that males with any type of mental disorder lost fewer years due to neoplasm-related deaths compared with the general population, although their cancer mortality rates were higher.
InterpretationMental disorders are associated with premature mortality. We provide a comprehensive analysis of mortality by different types of disorders, presenting both MRRs and premature mortality based on LYLs, displayed by age, sex, and cause of death. By providing accurate estimates of premature mortality, we reveal previously underappreciated features related to competing risks and specific causes of death.
FundingDanish National Research Foundation.
Details
1 National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
2 National Centre for Register-based Research, Aarhus University, Aarhus, Denmark; Centre for Integrated Register-based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark
3 Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
4 The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark; Danish Research Institute for Suicide Prevention, Mental Health Centre Copenhagen, Copenhagen, Denmark; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Center for Mental Health Research, Australian National University, Canberra, ACT, Australia
5 School of Demography, ANU College of Arts & Social Sciences, Australian National University, Canberra, ACT, Australia
6 Section of Biostatistics, University of Copenhagen, Copenhagen, Denmark
7 Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia; School of Public Health, Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia; Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
8 National Centre for Register-based Research, Aarhus University, Aarhus, Denmark; Department of Public Health, Aarhus University, Aarhus, Denmark
9 Department of Public Health, Aarhus University, Aarhus, Denmark
10 The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark; Danish Research Institute for Suicide Prevention, Mental Health Centre Copenhagen, Copenhagen, Denmark
11 Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia; School of Public Health, Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia; Centre for Clinical Research, Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia; Metro North Mental Health, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
12 National Centre for Register-based Research, Aarhus University, Aarhus, Denmark; Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia; Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
13 National Centre for Register-based Research, Aarhus University, Aarhus, Denmark; The Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH), Aarhus, Denmark