Average lifespan variation among people with mental disorders in Denmark: a nationwide, register-based cohort study.

AIMS: Mortality associated with mental disorders has been estimated using metrics such as mortality rate ratios and life expectancy. However, the variation around the average life expectancy has never been quantified. The main aim of this study was to measure life disparity for people with mental disorders as a measure of inequality at the time of death. METHODS: Using data from Danish registries, average life disparity was introduced and calculated to measure the lifespan variation associated with major types of mental disorders. Average life expectancy is also reported for completeness. RESULTS: Compared with the general population, people with mental disorders not only had shorter average life expectancy, but experienced larger average life disparity. For those diagnosed with a mental disorder, average life expectancy increased between 1995 and 2021; however, average life disparity declined in women only, and did not change for men. In addition, the differences in both metrics between those with mental disorders and the general population were largest for substance use disorders and schizophrenia spectrum disorders. For these disorders, the differences even increased during the study period. CONCLUSIONS: Mortality rates for individuals with mental disorders have been declining in recent decades in Denmark; however, the increase in the average life disparity emphasizes the increasing heterogeneity and inequality in lifespans within this group, which requires measures to promote a longer and more equal life for those with mental disorders.

Educational differences in years lived with disability due to mental and substance use disorders: a cohort study using nationwide Norwegian and Danish registries.

BACKGROUND: Findings from the Global Burden of Disease (GBD) study have shown that the burden of mental and substance use disorders is considerable, and unevenly distributed across demographic groups in the population. However, there is a lack of knowledge on how this burden differs by socioeconomic position. The aim of this study was to examine educational differences in years lived with disability (YLDs) from mental and substance use disorders among males and females in two high-income countries, taking comorbidity with other diseases into account. METHODS: The study included all registered residents in Denmark and Norway from 2011 to 2021. Diagnostic information was retrieved from records in the Norwegian National Patient Registry (NPR) and the Danish Psychiatric Central Research Register (PCRR) and used as proxy measures for disorder prevalence. Demographical and educational information was taken from administrative registries. The YLD is a measure of the non-fatal health loss in the population and was calculated by multiplying the duration of a disorder with a disability weight (DW), scaled between 0 and 1. Information on remission and DWs were retrieved from the GBD study and other sources, and disorder specific DWs were averaged by severity levels and adjusted for comorbidity. RESULTS: Educational gradients in YLD rates were found for mental and substance disorders overall, and for most of the specific disorders. The educational gradient was more pronounced for schizophrenia, intellectual disability and substance use disorders than for eating, anxiety, and affective disorders. Both higher YLD rates, and a larger attributed proportion of the total YLDs, were found for schizophrenia, intellectual disability, and substance use disorders in the groups with low versus high education. YLD rates for eating, anxiety, and affective disorders were more equal across educational levels, but constituted a smaller proportion of the total YLDs among the groups with low versus the groups with high educational level. CONCLUSION: Most of the disease burden related to mental and substance use disorders falls on those with the fewest years of education. This should be taken into consideration when public health targets aimed at improving mental health and reducing social inequalities in health are developed and implemented.

Association between Mental Disorders and Subsequent Medical Conditions.

BACKGROUND: Persons with mental disorders are at a higher risk than the general population for the subsequent development of certain medical conditions. METHODS: We used a population-based cohort from Danish national registries that included data on more than 5.9 million persons born in Denmark from 1900 through 2015 and followed them from 2000 through 2016, for a total of 83.9 million person-years. We assessed 10 broad types of mental disorders and 9 broad categories of medical conditions (which encompassed 31 specific conditions). We used Cox regression models to calculate overall hazard ratios and time-dependent hazard ratios for pairs of mental disorders and medical conditions, after adjustment for age, sex, calendar time, and previous mental disorders. Absolute risks were estimated with the use of competing-risks survival analyses. RESULTS: A total of 698,874 of 5,940,299 persons (11.8%) were identified as having a mental disorder. The median age of the total population was 32.1 years at entry into the cohort and 48.7 years at the time of the last follow-up. Persons with a mental disorder had a higher risk than those without such disorders with respect to 76 of 90 pairs of mental disorders and medical conditions. The median hazard ratio for an association between a mental disorder and a medical condition was 1.37. The lowest hazard ratio was 0.82 for organic mental disorders and the broad category of cancer (95% confidence interval [CI], 0.80 to 0.84), and the highest was 3.62 for eating disorders and urogenital conditions (95% CI, 3.11 to 4.22). Several specific pairs showed a reduced risk (e.g., schizophrenia and musculoskeletal conditions). Risks varied according to the time since the diagnosis of a mental disorder. The absolute risk of a medical condition within 15 years after a mental disorder was diagnosed varied from 0.6% for a urogenital condition among persons with a developmental disorder to 54.1% for a circulatory disorder among those with an organic mental disorder. CONCLUSIONS: Most mental disorders were associated with an increased risk of a subsequent medical condition; hazard ratios ranged from 0.82 to 3.62 and varied according to the time since the diagnosis of the mental disorder. (Funded by the Danish National Research Foundation and others; COMO-GMC ClinicalTrials.gov number, NCT03847753.).

Agreement between survey- and register-based measures of depression in Denmark.

BACKGROUND: Register-based studies of major depressive disorder (MDD) do not capture all prevalent cases, as untreated cases and diagnoses made by general practitioners are not recorded in the registers. We examined the prevalence and agreement of survey- and register-based measures of depression, and explored sociodemographic and health-related factors that may have influenced this agreement. METHODS: All 32,407 participants in the 2017 Central Denmark Region How are you? survey were linked to hospital and prescription records. A checklist for depressive symptoms within the last 14 days (Major Depression Inventory; MDI) from the survey was compared with register-based assessment of hospital-diagnosed MDD and/or prescriptions for antidepressants. We estimated agreement between survey-based and register-based measures for depression and used logistic regression models to explore selected associated factors. RESULTS: In total, 5.9% of How are you? survey participants screened positive for current depression on the MDI. Of these, 51.3% (95% confidence interval (CI): 49.0-53.6) filled a prescription for an antidepressant medication during the 10 years prior or 2 years following the administration of the survey, and 14.5% (95% CI: 12.9-16.2) were treated for MDD in a psychiatric hospital-based setting. When using a higher threshold of the MDI indicating more severe current depression, 22.8% (95% CI: 19.6-26.1) of those who screened positive also received an MDD diagnosis and 63.4% (95% CI: 59.7-67.2) were prescribed antidepressants during this 12-year period. Among those with current depression, female sex, older age, chronic diseases, hospital-treated self-harm, and being permanently outside the workforce were associated with having a register-based MDD diagnosis or antidepressant prescription. Among those with a register-based depression record, female sex, younger age, hospital-treated self-harm, stress, and severe loneliness were associated with current depression. CONCLUSION: We found that as few as 15% of individuals with current depression in the general Danish population were captured by the psychiatric hospital register, while 51% of these individuals were identifiable in the prescription register. These findings demonstrate that register-based measures significantly underestimate the true prevalence of depression by identifying only the cases that are most severe.

Inequalities in the burden of non-communicable diseases across European countries: a systematic analysis of the Global Burden of Disease 2019 study.

BACKGROUND: Although overall health status in the last decades improved, health inequalities due to non-communicable diseases (NCDs) persist between and within European countries. There is a lack of studies giving insights into health inequalities related to NCDs in the European Economic Area (EEA) countries. Therefore, the aim of the present study was to quantify health inequalities in age-standardized disability adjusted life years (DALY) rates for NCDs overall and 12 specific NCDs across 30 EEA countries between 1990 and 2019. Also, this study aimed to determine trends in health inequalities and to identify those NCDs where the inequalities were the highest. METHODS: DALY rate ratios were calculated to determine and compare inequalities between the 30 EEA countries, by sex, and across time. Annual rate of change was used to determine the differences in DALY rate between 1990 and 2019 for males and females. The Gini Coefficient (GC) was used to measure the DALY rate inequalities across countries, and the Slope Index of Inequality (SII) to estimate the average absolute difference in DALY rate across countries. RESULTS: Between 1990 and 2019, there was an overall declining trend in DALY rate, with larger declines among females compared to males. Among EEA countries, in 2019 the highest NCD DALY rate for both sexes were observed for Bulgaria. For the whole period, the highest DALY rate ratios were identified for digestive diseases, diabetes and kidney diseases, substance use disorders, cardiovascular diseases (CVD), and chronic respiratory diseases - representing the highest inequality between countries. In 2019, the highest DALY rate ratio was found between Bulgaria and Iceland for males. GC and SII indicated that the highest inequalities were due to CVD for most of the study period - however, overall levels of inequality were low. CONCLUSIONS: The inequality in level 1 NCDs DALYs rate is relatively low among all the countries. CVDs, digestive diseases, diabetes and kidney diseases, substance use disorders, and chronic respiratory diseases are the NCDs that exhibit higher levels of inequality across countries in the EEA. This might be mitigated by applying tailored preventive measures and enabling healthcare access.

The health care cost of comorbidity in individuals with mental disorders: A Danish register-based study.

AIM: The aim of the study was to estimate the annual health care cost by number of comorbid mental and somatic disorders in persons with a mental disorder. METHODS: All persons living in Denmark between 2004 and 2017 with a hospital diagnosis of a mental disorder were identified. We investigated the cost of different health care services: psychiatric hospitals, somatic hospitals, primary health care (e.g. general practitioners, psychologists and so on) and subsidised prescriptions. Within those with at least one mental disorder, we examined the costs for people with (a) counts of different types of mental disorders (e.g. exactly 1, exactly 2 and so on up to 8 or more) and (b) counts of different types of somatic disorders (e.g. no somatic disorders, exactly 1, exactly 2 and so on up to 15 or more). The estimates are reported in average cost per case and nationwide annual cost in Euro 2017. RESULTS: In total, 447,209 persons (238,659 females and 208,550 males) were diagnosed with at least one mental disorder in the study period. The average annual health care cost per case and nationwide cost was 4471 Euros and 786 million Euro, respectively, for persons with exactly one mental disorder, and 33,273 Euro and 3.6 million Euro for persons with eight or more mental disorders. The annual health care cost was 4613 Euro per case and 386 million Euro for persons without any somatic disorders, while the cost per case was 16,344 Euro and 0.7 million Euro in nationwide cost for persons with 15 or more disorders. The amount and proportion of the different health care costs varied by type of comorbidity and count of disorders. CONCLUSIONS: The annual health care cost per case was higher with increasing number of comorbid mental and somatic disorders, while the nationwide annual health care cost was lower with increasing number of comorbid disorders for persons with a mental disorder in Denmark.

Analysis of mortality metrics associated with a comprehensive range of disorders in Denmark, 2000 to 2018: A population-based cohort study.

BACKGROUND: The provision of different types of mortality metrics (e.g., mortality rate ratios [MRRs] and life expectancy) allows the research community to access a more informative set of health metrics. The aim of this study was to provide a panel of mortality metrics associated with a comprehensive range of disorders and to design a web page to visualize all results. METHODS AND FINDINGS: In a population-based cohort of all 7,378,598 persons living in Denmark at some point between 2000 and 2018, we identified individuals diagnosed at hospitals with 1,803 specific categories of disorders through the International Classification of Diseases-10th Revision (ICD-10) in the National Patient Register. Information on date and cause of death was obtained from the Registry of Causes of Death. For each of the disorders, a panel of epidemiological and mortality metrics was estimated, including incidence rates, age-of-onset distributions, MRRs, and differences in life expectancy (estimated as life years lost [LYLs]). Additionally, we examined models that adjusted for measures of air pollution to explore potential associations with MRRs. We focus on 39 general medical conditions to simplify the presentation of results, which cover 10 broad categories: circulatory, endocrine, pulmonary, gastrointestinal, urogenital, musculoskeletal, hematologic, mental, and neurologic conditions and cancer. A total of 3,676,694 males and 3,701,904 females were followed up for 101.7 million person-years. During the 19-year follow-up period, 1,034,273 persons (14.0%) died. For 37 of the 39 selected medical conditions, mortality rates were larger and life expectancy shorter compared to the Danish general population. For these 37 disorders, MRRs ranged from 1.09 (95% confidence interval [CI]: 1.09 to 1.10) for vision problems to 7.85 (7.77 to 7.93) for chronic liver disease, while LYLs ranged from 0.31 (0.14 to 0.47) years (approximately 16 weeks) for allergy to 17.05 (16.95 to 17.15) years for chronic liver disease. Adjustment for air pollution had very little impact on the estimates; however, a limitation of the study is the possibility that the association between the different disorders and mortality could be explained by other underlying factors associated with both the disorder and mortality. CONCLUSIONS: In this study, we show estimates of incidence, age of onset, age of death, and mortality metrics (both MRRs and LYLs) for a comprehensive range of disorders. The interactive data visualization site (https://nbepi.com/atlas) allows more fine-grained analysis of the link between a range of disorders and key mortality estimates.

Temporal changes in sex- and age-specific incidence profiles of mental disorders-A nationwide study from 1970 to 2016.

OBJECTIVE: Information on mental disorders over time is critical for documenting changes in population burden, and aiding understanding of potential causal and non-causal factors. The aim of this study was to provide temporal changes in the sex- and age-specific incidence rates (IR) of mental disorders diagnosed in Danish hospitals during five decades and investigate whether such changes may be attributable to changes in administrative reporting practice. METHODS: This population-based cohort study included all people living in Denmark between 1970 and 2016. Mental disorders diagnoses were obtained from the Danish Psychiatric Central Research Register. We estimated the IR of each mental disorder (all persons, and sex- and age-specific IRs) and examined the impact of two administrative changes. RESULTS: Our study included 9 107 157 people, followed for 233.0 million person-years. During follow-up, 9.5% were diagnosed with at least one mental disorder. The IR for any mental disorder was 39.0 per 10,000 person-years. Despite fluctuations, this increased between 1970-84 and 2005-2016, from 28.9 to 63.0 per 10,000 person-years. Increases were most pronounced for younger age groups. Administrative changes did appear to influence incidence rates. CONCLUSION: Mental disorder IRs have increased in Denmark since 1970, with age of diagnosis shifting downwards. Both trends were likely impacted by administrative changes, while the latter is likely to be (partly) attributable to earlier detection and increased reporting of child-onset conditions. Our findings may provide valuable context of the epidemiology of mental disorders across age groups for comparison with other studies and populations.

A comprehensive analysis of mortality-related health metrics associated with mental disorders: a nationwide, register-based cohort study.

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. METHODS: In 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. FINDINGS: 7 369 926 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. INTERPRETATION: Mental 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. FUNDING: Danish National Research Foundation.

Healthcare use before and after changing disability pension policy: a regional Danish cohort study.

BACKGROUND: The social security policy for disability pension (DP) was changed in Denmark in 2013 and eligibility requirements were tightened. We describe and compare the use of healthcare among individuals with incident DP before and after the policy change. METHODS: This was a follow-up study based on data from nationwide databases. The study included individuals with incident DP aged 18-64 years and living in The North Denmark Region. We included individuals with incident DP before (2010-12, n = 6286) and after (2014-15, n = 1042) the 2013 policy change. Poisson regression was used to examine group differences in (i) contact to healthcare and (ii) hospitalization. For this purpose, we used incidence rate ratios stratified on type of contact before being awarded DP. RESULTS: We found a change of diagnoses for healthcare use towards higher proportions of cardiovascular, pulmonary, neurological and cancer diseases and lower proportion with musculoskeletal disorder in the populations being granted DP after policy changes. For individuals with psychiatric contact before being granted DP, we found no significant differences between periods in psychiatric healthcare after DP was awarded. For individuals with somatic contact before being granted DP, we found an increased risk of contact to somatic healthcare and hospitalization after DP requirements were tightened. CONCLUSION: The study demonstrated that individuals who were granted DP after the eligibility requirements had been tightened suffered from more medical conditions and had an ongoing need for healthcare. In contrast, no significant difference in risk of psychiatric contact or hospitalization after DP was demonstrated.

Socioeconomic predictors of referral to a diagnostic centre on suspected adverse events following HPV vaccination.

Background: In Denmark, the human papillomavirus (HPV) vaccines have been suspected of adverse events since 2014. However, as no causal associations between the HPV vaccines and numerous diseases have been demonstrated, factors prior to vaccination may influence the risk of suspecting the HPV vaccines of causing symptoms. We studied the associations between individual and parental socioeconomic characteristics and the risk of referral to a diagnostic centre in a female population aged 11-29 years with a first HPV vaccination in January 2008 to June 2015. Methods: Individual and parental data from national registries were linked using the unique personal identification number. Logistic regression analyses were used to estimate crude and adjusted odds ratio's according to each individual and parental socioeconomic factor with two-sided 95% 95% CI. Results: The cohort consisted of 453 216 individuals of which 1316 (0.29%) were referred to a diagnostic centre in 2015. Having a mother outside the workforce or an unemployed mother was associated with an increased risk of referral, while girls and women who had fathers with a higher educational level were less likely to be referred. In addition, women aged 20-29 years who were unemployed or outside the workforce prior to vaccination had increased odds of being referred to a diagnostic centre. Conclusion: We found social inequality in the referral to a diagnostic centre following HPV vaccination. This might be explained by an increased morbidity in girls and women of lower socioeconomic status.

The Role of Socioeconomic Position in the Association Between Mental Disorders and Mortality: A Systematic Review and Meta-Analysis.

Importance: Studies are lacking summarizing how the association between mental disorders and mortality varies by socioeconomic position (SEP), particularly considering different aspects of SEP, specific types of mental disorders, and causes of death. Objective: To investigate the role of SEP in the association between mental disorders and mortality and the association between SEP and mortality among people with mental disorders. Data Sources: MEDLINE, Embase, PsycINFO, and Web of Science were searched from January 1, 1980, through April 3, 2023, and a snowball search of reference and citation lists was conducted. Study Selection: Inclusion criteria were observational studies estimating the associations between different types of mental disorders and mortality, stratified by SEP and between SEP and mortality in people with mental disorders. Data Extraction and Synthesis: Pairs of reviewers independently extracted data using a predefined data extraction form and assessed the risk of bias using the adapted Newcastle-Ottawa scale. Graphical analyses of the dose-response associations and random-effects meta-analyses were performed. Heterogeneity was explored through meta-regressions and sensitivity analyses. Main Outcomes and Measures: All-cause and cause-specific mortality. Results: Of 28 274 articles screened, 71 including more than 4 million people with mental disorders met the inclusion criteria (most of which were conducted in high-income countries). The relative associations between mental disorders and mortality were similar across SEP levels. Among people with mental disorders, belonging to the highest rather than the lowest SEP group was associated with lower all-cause mortality (pooled relative risk [RR], 0.79; 95% CI, 0.73-0.86) and mortality from natural causes (RR, 0.73; 95% CI, 0.62-0.85) and higher mortality from external causes (RR, 1.18; 95% CI, 0.99-1.41). Heterogeneity was high (I2 = 83% to 99%). Results from subgroup, sensitivity, and meta-regression analyses were consistent with those from the main analyses. Evidence on absolute scales, specific diagnoses, and specific causes of death was scarce. Conclusion and Relevance: This study did not find a sufficient body of evidence that SEP moderated the relative association between mental disorders and mortality, but the underlying mortality rates may differ by SEP group, despite having scarcely been reported. This information gap, together with our findings related to SEP and a possible differential risk between natural and external causes of death in individuals with specific types of mental disorders, warrants further research.

The association between mental disorders and subsequent years of working life: a Danish population-based cohort study.

BACKGROUND: Mental disorders can affect workforce participation via a range of mechanisms. In this study, we aimed to estimate the association between different types of mental disorders and working years lost, defined as the number of years not actively working or enrolled in an educational programme. METHODS: In this population-based cohort study, we included all people aged 18-65 years (mean 38·0 [SD 13·9]) in the Danish Civil Registration System from Jan 1, 1995 to Dec 31, 2016. Information on mental disorders was obtained from the Danish Psychiatric Central Research Register and information on labour market characteristics was obtained from administrative registers. Follow-up started at age 18 years, immigration to Denmark, or on Jan 1, 1995, whichever came later; and it ended at age 65 years, death, emigration from Denmark, disability pension, voluntary early retirement, or Dec 31, 2016 (whichever came earlier). As the main outcome, we estimated working years lost for those diagnosed with any mental disorder and 24 types of mental disorders, as well as for the general population of same age and sex. We decomposed total working years lost into periods of unemployment or sick leave, disability pension, voluntary early retirement, or death. Data on ethnicity were not available through administrative registers. FINDINGS: A total of 5 163 321 individuals, 2 642 383 men and 2 520 938 women, were followed up for 65·4 million person-years. Overall, 488 775 (9·47%) individuals were diagnosed with a mental disorder. On average, individuals with mental disorders lost an additional 10·52 (95% CI 10·48-10·57) years of working life compared with the general Danish population. Receiving a disability pension (7·54 [7·49-7·59] years) and longer periods of unemployment (2·24 [2·21-2·27] years) accounted for most of this difference. INTERPRETATION: Our findings foreground the substantial impact of mental disorders on workforce participation. There is a need to invest in programmes that reduce the burden of working years lost and assist people with mental disorders in returning to the workforce. FUNDING: Lundbeck Foundation and Danish National Research Foundation.

Representativeness of survey participants in relation to mental disorders: a linkage between national registers and a population-representative survey.

Introduction: Surveys and registers have provided important insights into the mental health of the community. However, both sources have strengths and limitations. While participation in surveys has been shown to be lower among those with mental disorders, misclassification and limited information on confounders are typical issues for registers. Objectives: To examine if participants of the Central Denmark Region's 2017 How are you? survey were representative of the general population in terms of mental disorder diagnoses. Methods: By linking data from the Central Denmark Region's 2017 How are you? survey with the Danish national registers, we compared the frequency of mental disorder diagnoses among (a) participants in the survey (n = 32,417), before and after applying non-response weights, and (b) the entire population who were eligible to participate (n = 1,063,082; 16 years of age or older on 10th January 2017 and registered as living in the Central Denmark Region). Using logistic regression models, we estimated associations between being diagnosed with any mental disorder and nine general medical conditions to assess whether selection into the survey appeared to bias these associations. Results: Based on register data, 10.4% (n = 110,492) of the eligible population had received a diagnosis of any mental disorder prior to the date of this survey. Among the unweighted survey sample, 8.2% (n = 2,648) had received a diagnosis; once non-response weights were applied, this corresponded to 9.5%. Representativeness varied by sex, age and type of mental disorder. For example, people with organic disorders or substance use disorders were generally underrepresented among survey participants of all ages; however, representativeness of common disorders such as mood or neurotic disorders was generally good. With respect to the association of any mental disorder and general medical conditions, we found that estimates were similar for survey samples (both weighted and unweighted) compared to the entire eligible population. Conclusions: People with a previous diagnosis of a mental disorder are slightly underrepresented in the survey. However, this selection bias was minimized when non-response weights were applied. Associations between mental disorders and general medical conditions did not appear to be affected by selection bias. With the application of non-response weights, the survey provided a sample representative of the general population in terms of mental disorder diagnoses.

The contribution of general medical conditions to the non-fatal burden of mental disorders: register-based cohort study in Denmark.

BACKGROUND: General medical conditions (GMCs) often co-occur with mental and substance use disorders (MSDs). AIMS: To explore the contribution of GMCs to the burden of disease in people with MSDs, and investigate how this varied by age. METHOD: A population-based cohort of 6 988 507 persons living in Denmark during 2000-2015 followed for up to 16 years. Danish health registers were used to identify people with MSDs and GMCs. For each MSD, years lived with disability and health loss proportion (HeLP) were estimated for comorbid MSDs and GMCs, using a multiplicative model for disability weights. RESULTS: Those with any MSD lost the equivalent of 43% of healthy life (HeLP = 0.43, 95% CI 0.40-0.44) after including information on GMCs, which was an increase from 25% before including GMCs (HeLP = 0.25, 95% CI 0.23-0.27). Schizophrenia was associated with the highest burden of disease (HeLP = 0.77, 95% CI 0.68-0.85). However, within each disorder, the relative contribution of MSDs and GMCs varied. For example, in those diagnosed with schizophrenia, MSDs and GMCs accounted for 86% and 14% of the total health loss; in contrast, in those with anxiety disorders, the same proportions were 59% and 41%. In general, HeLP increased with age, and was mainly associated with increasing rates of pulmonary, musculoskeletal and circulatory diseases. CONCLUSIONS: In those with mental disorders, the relative contribution of comorbid GMCs to the non-fatal burden of disease increases with age. GMCs contribute substantially to the non-fatal burden of disease in those with MSDs.

Mortality Associated With Mental Disorders and Comorbid General Medical Conditions.

Importance: Premature mortality has been observed among people with mental disorders. Comorbid general medical conditions contribute substantially to this reduction in life expectancy. Objective: To provide an analysis of mortality associated with comorbidity between a broad range of mental disorders and general medical conditions. Design, Setting, and Participants: Population-based cohort study of 5 946 800 individuals born in Denmark from 1900 to 2015 and residing in the country at the start of follow-up (January 1, 2000, or their date of birth, whichever occurred later). Exposures: Danish health registers were used to identify people with mental disorders and general medical conditions. Main Outcomes and Measures: Considering pairs of mental disorders and general medical conditions, we calculated mortality rate ratios (MRRs) and differences in life expectancy (ie, life-years lost) to assess the association of mortality with both disorders of interest compared with the mental disorder of interest, the general medical condition of interest, and neither disorder of interest. Results: The study population comprised 2 961 397 males and 2 985 403 females, with a median (IQR) age of 32.0 years (7.3-52.9) at start of follow-up and 48.9 years (42.5-68.8) at the end. Based on all pairs of comorbid mental disorders and general medical conditions, the mean MRR compared with people without these conditions was 5.90 (median, 4.94; IQR, 3.80-7.30), and the mean reduction of life expectancy compared with the general population was 11.35 years (median, 11.08; range, 5.27-23.53; IQR, 8.22-13.72). The association with general medical condition comorbidity in those with mental disorders varied by general medical condition; for example, the addition of a neurological condition for each of the mental disorders was associated with a mean MRR of 1.22, whereas for cancer, the mean MRR for all mental disorders was 4.07. Conclusions and Relevance: In this study, shorter life expectancy was associated with comorbid mental disorders and general medical conditions compared with the entire population and also when compared with patients who had either mental disorders only or general medical conditions only. Prevention and early detection of comorbidities could reduce premature mortality in patients with mental disorders.

The cost of mental disorders in Denmark: a register-based study.

The aim of the study was to undertake a detailed analysis of healthcare cost, public transfer payments, and income loss associated with a broad range of mental disorders in Denmark. Based on all persons living in Denmark, we identified those with a hospital diagnosis of one of 18 types of mental disorders and 10 age- and sex-matched controls per case. For each mental disorder, the outcomes were nationwide totals, cost per case, and cost per capita, investigated by sex, age strata, and the number of years after diagnosis. We found a substantial annual income loss of 5 billion Euros and excess healthcare cost of 1 billion Euros for persons with any mental disorder. Each mental disorder was associated with an income loss, excess healthcare cost, and excess public transfer payments compared to matched controls. An interactive data visualisation site with summary data is available at https://nbepi.com/cost .

Register-based metrics of years lived with disability associated with mental and substance use disorders: a register-based cohort study in Denmark.

BACKGROUND: Mental disorders account for a substantial proportion of the years lived with disability (YLDs) globally. These estimates have generally been calculated top down based on summary statistics. The aim for this study was to calculate YLDs and a novel related measure, Health Loss Proportion (HeLP), for 18 mental and substance use disorders, based on person-level register data (bottom up). METHODS: A cohort of 6 989 627 Danish residents (5·9% had a diagnosis of a mental or substance use disorder registered in the Danish Psychiatric Central Research Register) was investigated. YLDs (the duration of disease multiplied by a disability weight) were calculated for the disorder of interest and for comorbid mental and substance use disorders. HeLPs were estimated as YLDs associated with an index disorder and comorbid mental and substance use disorders divided by person-years at risk in persons with the index disorder. All analyses were adjusted for mental and substance use comorbidity using a multiplicative model of disability weights. FINDINGS: Major depressive disorder was the most prevalent disorder, although schizophrenia was the leading cause of YLDs in both sexes combined (YLDs 273·3 [95 % CI 232·3-313·6] per 100 000 person-years). People diagnosed with schizophrenia lost the equivalent of 73% (63-83%) of healthy life per year due to mental and substance use disorders, the largest HeLP of all mental and substance use disorders. Comorbidity of mental and substance use disorders accounted for 69-83% of HeLPs in people with either cannabis use disorders, other drug use disorder and ADHD. By contrast, comorbidity explained 11-23% of the HeLPs in people with autism spectrum disorders, conduct disorder, and schizophrenia. INTERPRETATION: Substantial variation in disability was observed across age, sex, and disorders. The new HeLP metric provides novel details of the contribution of comorbidity to the disability associated with mental and substance use disorders. FUNDING: The Danish National Research Foundation, Queensland Government Department of Health, European Union's Horizon 2020, Lundbeck Foundation, Stanley Medical Research Institute. TRANSLATION: For the Danish translation of the abstract see Supplementary Materials section.

lillies: An R package for the estimation of excess Life Years Lost among patients with a given disease or condition.

Life expectancy at a given age is a summary measure of mortality rates present in a population (estimated as the area under the survival curve), and represents the average number of years an individual at that age is expected to live if current age-specific mortality rates apply now and in the future. A complementary metric is the number of Life Years Lost, which is used to measure the reduction in life expectancy for a specific group of persons, for example those diagnosed with a specific disease or condition (e.g. smoking). However, calculation of life expectancy among those with a specific disease is not straightforward for diseases that are not present at birth, and previous studies have considered a fixed age at onset of the disease, e.g. at age 15 or 20 years. In this paper, we present the R package lillies (freely available through the Comprehensive R Archive Network; CRAN) to guide the reader on how to implement a recently-introduced method to estimate excess Life Years Lost associated with a disease or condition that overcomes these limitations. In addition, we show how to decompose the total number of Life Years Lost into specific causes of death through a competing risks model, and how to calculate confidence intervals for the estimates using non-parametric bootstrap. We provide a description on how to use the method when the researcher has access to individual-level data (e.g. electronic healthcare and mortality records) and when only aggregated-level data are available.