Simulation-based sample size calculations of marginal proportional means models for recurrent events with competing risks.

In randomised controlled trials, the outcome of interest could be recurrent events, such as hospitalisations for heart failure. If mortality rates are non-negligible, both recurrent events and competing terminal events need to be addressed when formulating the estimand and statistical analysis is no longer trivial. In order to design future trials with primary recurrent event endpoints with competing risks, it is necessary to be able to perform power calculations to determine sample sizes. This paper introduces a simulation-based approach for power estimation based on a proportional means model for recurrent events and a proportional hazards model for terminal events. The simulation procedure is presented along with a discussion of what the user needs to specify to use the approach. The method is flexible and based on marginal quantities which are easy to specify. However, the method introduces a lack of a certain type of dependence. This is explored in a sensitivity analysis which suggests that the power is robust in spite of that. Data from a randomised controlled trial, LEADER, is used as the basis for generating data for a future trial. Finally, potential power gains of recurrent event methods as opposed to first event methods are discussed.

Socio-economic functioning in patients with bipolar disorder and their unaffected siblings - results from a nation-wide population-based longitudinal study.

BACKGROUND: Few studies have reported real-life data on socio-economic functioning in patients with bipolar disorder and their unaffected first-degree relatives. METHODS: We used Danish nation-wide population-based longitudinal register linkage to investigate socio-economic functioning in 19 955 patients with bipolar disorder, their 13 923 siblings and 20 sex, age and calendar-matched control individuals from the general population. Follow-up was from 1995 to 2017. RESULTS: Patients with a diagnosis of bipolar disorder had lower odds of having achieved the highest educational level [OR 0.75 (95% confidence interval (CI) 0.73-0.77)], being employed [OR 0.16 (95% CI 0.159-0.168)], having achieved the 80% highest quartile of income [OR 0.33 (95% CI 0.32-0.35)], cohabitating [OR 0.44 (95% CI 0.43-0.46)] and being married [OR 0.54 (95% CI 0.52-0.55)] at first contact to hospital psychiatry as inpatient or outpatient compared with control individuals from the general population. Similarly, siblings to patients with bipolar disorder had a lower functioning within all five socio-economic areas than control individuals. Furthermore, patients and partly siblings showed substantially decreased ability to enhance their socio-economic functioning during the 23 years follow-up compared to controls. CONCLUSIONS: Socio-economic functioning is substantially decreased in patients with bipolar disorder and their siblings and does not improve during long-term follow-up after the initial hospital contact, highlighting a severe and overlooked treatment gap.

Discussion of "A formal causal interpretation of the case-crossover design".

Discussion on "A formal causal interpretation of the case-crossover design" by Zach Shahn, Miguel A. Hernan, and James M. Robins.

Maternal stress during pregnancy and gestational duration: A cohort study from the Danish National Birth Cohort.

BACKGROUND: Preterm birth is one of the most important contributors to neonatal mortality and morbidity. Experiencing stress during pregnancy may increase the risk of adverse birth outcomes, including preterm birth. This association has been observed in previous studies, but differences in measures used limit comparability. OBJECTIVE: The objective of the study was to investigate the association between two measures of maternal stress during pregnancy, life stress and emotional distress, and gestation duration. METHODS: Women recruited in the Danish National Birth Cohort from 1996 to 2002, who provided information on their stress level during pregnancy and expecting a singleton baby, were included in the study. We assessed the associations between the level of life stress and emotional distress in quartiles, both collected at 31 weeks of pregnancy on average, and the rate of giving birth using Cox regression within intervals of the gestational period. RESULTS: A total of 80,991 pregnancies were included. Women reporting moderate or high levels of life stress vs no stress had a higher rate of giving birth earlier within all intervals of gestational age (e.g. high level: 27-33 weeks: hazard ratio (HR) 1.38, 95% confidence interval (CI) 1.04, 1.84; 34-36 weeks: 1.10, 95% CI 0.97, 1.25; 37-38 weeks: 1.21, 95% CI 1.15, 1.28). These associations between life stress and preterm birth were mainly driven by pregnancy worries. For emotional distress, a high level of distress was associated with shorter length of gestation in the preterm (27-33 weeks: 1.38, 95% CI 1.02, 1.86; 34-36 weeks: 1.05, 95% CI 0.91, 1.19) and early term (1.11, 95% CI 1.04, 1.17) intervals. CONCLUSIONS: Emotional distress and life stress were shown to be associated with gestational age at birth, with pregnancy-related stress being the single stressor driving the association. This suggests that reverse causality may, at least in parts, explain the earlier findings of stress as a risk factor for preterm birth.

Exposure to residential mold and dampness and the associations with respiratory tract infections and symptoms thereof in children in high income countries: A systematic review and meta-analyses of epidemiological studies.

BACKGROUND: Multiple reviews have been conducted on the associations between residential mold and dampness and respiratory outcomes in children, with few specifically investigating respiratory tract infections (RTIs). OBJECTIVE: We aimed to review and synthesize the available epidemiological literature on mold and dampness and risk of RTIs and respiratory symptoms compatible with RTIs in children living in high-income countries. METHOD: We performed a systematic search of literature available from MEDLINE, Embase, and Web of Science for observational studies. We conducted meta-analyses using two-level random effects (RE) and multi-level random effects (ML) models for contrasts of three exposure and three outcome categories, including multiple estimates reported by single studies. We report central estimates for pooled odds ratios (OR) and 95 % confidence intervals (CI).We conducted a risk of bias assessment using the Joanna Briggs Initiative (JBI) checklists for cross-sectional, case-control, and cohort studies. We additionally report on cumulative meta-analyses, leave-one-out analyses of single estimates, subgroup analyses by study quality and study design and inclusion of all effect estimates. RESULTS: Of the 932 studies initially screened by title and abstract, we included 30 studies with 267 effect estimates that met the inclusion criteria. Most were cross-sectional (n = 22), with fewer cohort (n = 5) and case-control (n = 3) studies. Most of the studies were according to the bias assessment of poor or fair quality (n = 24). The main meta-analyses generally provided similar results regardless of statistical model and central estimates ranged from OR 1.28 (95 % CI; 1.08, 1.53) for dampness and RTIs to OR 1.76 (95 % CI; 1.64, 1.88) for mold and respiratory symptoms. Most analyses were of moderate heterogeneity. Funnel plots did not indicate strong publication bias. CONCLUSION: Our results are compatible with a weak to moderate effect of residential mold and or dampness on risk of RTIs in children in high-income countries. However, these results are based primarily on cross-sectional studies.

The effect of the SAFE intervention on post-discharge suicidal behavior: a quasi-experimental study using propensity score matching.

OBJECTIVES: The risk of suicidal behavior after discharge from psychiatric admission is high. The aim of this study was to examine whether the SAFE intervention, an implementation of a systematic safer discharge procedure, was associated with a reduction in suicidal behavior after discharge. METHODS: The SAFE intervention was implemented at Mental Health Center Copenhagen in March 2018 and consisted of three systematic discharge procedures: (1) A face-to-face meeting between patient and outpatient staff prior to discharge, (2) A face-to-face meeting within the first week after discharge, and (3) Involvement of relatives. Risk of suicide attempt at six-month post-discharge among patients discharged from the SAFE intervention was compared with patients discharged from comparison mental health centers using propensity score matching. RESULTS: 7604 discharges took place at the intervention site, which were 1:1 matched with discharges from comparison sites. During the six months of follow-up, a total of 570 suicide attempts and 25 suicides occurred. The rate of suicide attempt was 11,652 per 100,000 person-years at the SAFE site, while it was 10,530 at comparisons sites. No observable difference in suicide attempt 1.10 (95% CI: 0.89-1.35) or death by suicide (OR = 1.27; 95% CI:0.58-2.81) was found between sites at 6-month follow-up. CONCLUSION: No difference in suicidal behavior between the sites was found in this pragmatic study. High rates of suicidal behavior were found during the 6-months discharge period, which could suggest that a preventive intervention should include support over a longer post-discharge period than the one-week follow-up offered in the SAFE intervention.

Body height and spinal pain in adolescence: a cohort study from the Danish National Birth Cohort.

OBJECTIVES: To investigate how body height and trajectories of height from infancy through childhood and adolescence were associated with spinal pain in pre- and late adolescence. METHODS: This prospective study included 43,765 individuals born into The Danish National Birth Cohort (DNBC) from 1996 to 2003. DNBC-data were linked with health and social data identified from Statistics Denmark registers. Spinal pain was self-reported in both the 11-year- and 18-year follow-up of DNBC and classified according to severity. Body height was measured from birth and onwards and further modelled as distinct developmental height trajectories by using latent growth curve modelling. Associations were estimated by using multinomial logistic regression models. RESULTS: Taller body height in childhood and adolescence was associated with approximately 20% increased likelihood of spinal pain in pre- and late adolescence among girls compared to their peers in the normal height group. For boys, taller body height was associated with spinal pain by late adolescence only. Spinal pain in pre-adolescence almost doubled the likelihood of spinal pain in late adolescence regardless of body height at age 18. Height trajectories confirmed the relationship for girls with the tall individuals being most likely to have spinal pain in both pre- and late adolescence. CONCLUSION: Tall body height during childhood and adolescence predisposes to spinal pain among girls in both pre-and late adolescence, and among boys in late adolescence. Body height is a contributing factor to the pathogenesis of spinal pain in adolescence; however, the mechanisms may be related to growth velocity, but for now uncertain.

Expected life years compared to the general population.

For cohorts with long-term follow-up, the number of years lost due to a certain disease yields a measure with a simple and appealing interpretation. Recently, an overview of the methodology used for this goal has been published, and two measures have been proposed. In this work, we consider a third option that may be useful in settings in which the other two are inappropriate. In all three measures, the survival of the given dataset is compared to the expected survival in the general population which is calculated using external mortality tables. We thoroughly analyze the differences between the three measures, their assumptions, interpretation, and the corresponding estimators. The first measure is defined in a competing risk setting and assumes an excess hazard compared to the population, while the other two measures also allow estimation for groups that live better than the general population. In this case, the observed survival of the patients is compared to that in the population. The starting point of this comparison depends on whether the entry into the study is a hazard changing event (e.g., disease diagnosis or the age at which the inclusion criteria were met). Focusing on the newly defined life years difference measure, we study the estimation of the variance and consider the possible challenges (e.g., extrapolation) that occur in practice. We illustrate its use with a dataset of French Olympic athletes. Finally, an efficient R implementation has been developed for all three measures which make this work easily available to subsequent users.

Effectiveness of medical treatment for bipolar disorder regarding suicide, self-harm and psychiatric hospital admission: between- and within-individual study on Danish national data.

BACKGROUND: Mood stabilisers are the main treatment for bipolar disorder. However, it is uncertain which drugs have the best outcomes. AIMS: To investigate whether rates of suicide, self-harm and psychiatric hospital admission in individuals with bipolar disorder differ between mood stabilisers. METHOD: A cohort design was applied to people aged ≥15 years who were diagnosed with bipolar disorder and living in Denmark during 1995-2016. Treatment with lithium, valproate, other mood stabilisers and antipsychotics were compared in between- and within-individual analyses, and adjusted for sociodemographic characteristics and previous self-harm. RESULTS: A total of 33 337 individuals with bipolar disorder were included (266 900 person-years). When compared with individuals not receiving treatment, those receiving lithium had a lower rate of suicide (hazard ratio 0.40, 95% CI 0.31-0.51). When comparing treatment and non-treatment periods in the same individuals, lower rates of self-harm were found for lithium (hazard ratio 0.74, 95% CI 0.61-0.91). Lower rates of psychiatric hospital admission were found for all drug categories compared with non-treatment periods in within-individual analyses (P<0.001). The low rates of self-harm and hospital admission for lithium in within-individual analyses were supported by results of between-individual analyses. CONCLUSIONS: Lithium was associated with lower rates of suicide, self-harm and psychiatric hospital readmission in all analyses. With respect to suicide, lithium was superior to no treatment. Although confounding by indication cannot be excluded, lithium seems to have better outcomes in the treatment of bipolar disorder than other mood stabilisers.

Pregnancy in women with MS: Impact on long-term disability accrual in a nationwide Danish Cohort.

BACKGROUND: Pregnancy is considered to influence the disease course in women with multiple sclerosis (MS). OBJECTIVE: The aim of this study was to investigate the effect of pregnancy on long-term disability accrual in women with MS. METHODS: The Danish Multiple Sclerosis Registry (DMSR) was used to identify women diagnosed with clinically isolated syndrome or relapsing-remitting MS. Cox models with pregnancy as a time-dependent exposure and propensity score (PS) models were used to evaluate time to reach confirmed Expanded Disability Status Scale (EDSS) score of 4 and 6. RESULTS: A total of 425 women became parous and 840 remained nulliparous. When including pregnancy as a time-dependent exposure, a non-significant association with time to reach EDSS 4 (hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.61-1.20) and EDSS 6 (HR 0.70, 95% CI 0.40-1.20) was found. Correspondingly, the PS model showed no association with pregnancy on time to reach EDSS 4 (HR 0.85, 95% CI 0.56-1.28). CONCLUSION: This study concludes that pregnancy does not affect long-term disability accumulation.

Analyzing differences between restricted mean survival time curves using pseudo-values.

Hazard ratios are ubiquitously used in time to event analysis to quantify treatment effects. Although hazard ratios are invaluable for hypothesis testing, other measures of association, both relative and absolute, may be used to fully elucidate study results. Restricted mean survival time (RMST) differences between groups have been advocated as useful measures of association. Recent work focused on model-free estimates of the difference in restricted mean survival through follow-up times, instead of focusing on a single time horizon. The resulting curve can be used to quantify the association in time units with a simultaneous confidence band. In this work a model-based estimate of the curve is proposed using pseudo-values allowing for possible covariate adjustment. The method is easily implementable with available software and makes possible to compute a simultaneous confidence region for the curve. The pseudo-values regression using multiple restriction times is in good agreement with the estimates obtained by standard direct regression models fixing a single restriction time. Moreover, the proposed method is flexible enough to reproduce the results of the non-parametric approach when no covariates are considered. Examples where it is important to adjust for baseline covariates will be used to illustrate the different methods together with some simulations.

Mental health and physical activity in vocational education and training schools students: a population-based survey.

BACKGROUND: The prevalence of young people not adhering to the World Health Organization (WHO) physical activity guidelines is high, especially among students in vocational education and training, compared to fellow peers. Also, low levels of mental health have been found in this group, however, to a lesser degree than peers in general education. As positive mental health aspects have more generally been found to be associated with increased likelihood of physical activity in young people, this study examined the association between mental health and physical activity among Danish students in vocational education and training. METHODS: Students in vocational education and training (N = 5277, mean age 24.3 years, range 15.8-64.0 years) responded to a national representative survey assessing four aspects of mental health (well-being, self-efficacy, self-esteem and life satisfaction) and physical activity. Physical activity was dichotomized as adherence to the WHO minimum guidelines or not. Logistic regression was used to examine if each mental health aspect was associated with physical activity in crude and adjusted models. RESULTS: A positive dose-response association was found between all aspects of mental health and adherence to WHO physical activity guidelines. However, the association between self-esteem and physical activity was modified by gender, with a dose-response relationship found only among males. CONCLUSIONS: Higher levels of positive mental health were associated with better odds of achieving WHO physical activity guidelines in a dose-response-manner. Prospective studies are needed to further elucidate the causal relationship between mental health and physical activity. Future interventions must pay attention to differential gender effects.

Methodological challenges in the analysis of recurrent events for randomised controlled trials with application to cardiovascular events in LEADER.

Analysis of recurrent events is becoming increasingly popular for understanding treatment effects in randomised controlled trials. The analysis of recurrent events can improve efficiency and capture disease burden compared to standard time-to-first event analyses. However, the added knowledge about the multi-state process comes at the cost of modelling complexity. High mortality rates can complicate matters even more. A case study using data from a randomised controlled trial, LEADER, is presented to highlight interpretation of common methods as well as potential pitfalls when analysing recurrent events in the presence of a competing risk. The presented methods either target features of the underlying intensity functions or marginal traits of a multi-state process which includes terminal events or not. In particular, approaches to handle death as a part of an event and as a competing risk are discussed. A new method targeting the marginal mean function for a composite endpoint, which includes both death as a component and as a competing risk, will be introduced. Finally, recommendations for how to capture meaningful treatment effects in randomised controlled trials when analysing recurrent and terminal events will be made.

Inference for transition probabilities in non-Markov multi-state models.

Multi-state models are frequently used when data come from subjects observed over time and where focus is on the occurrence of events that the subjects may experience. A convenient modeling assumption is that the multi-state stochastic process is Markovian, in which case a number of methods are available when doing inference for both transition intensities and transition probabilities. The Markov assumption, however, is quite strict and may not fit actual data in a satisfactory way. Therefore, inference methods for non-Markov models are needed. In this paper, we review methods for estimating transition probabilities in such models and suggest ways of doing regression analysis based on pseudo observations. In particular, we will compare methods using land-marking with methods using plug-in. The methods are illustrated using simulations and practical examples from medical research.

A nationwide population-based longitudinal study mapping psychiatric disorders during lifetime in siblings to patients with bipolar disorder.

OBJECTIVE: The aim was to map rates and cumulative incidences of psychiatric disorders during lifetime for siblings to patients with a diagnosis of bipolar disorder compared with the general population. METHODS: Danish nationwide population-based longitudinal register linkage study including 13,923 unaffected siblings to 19,955 patients with bipolar disorder and 278,460 unaffected control individuals from the general population matched according to year of birth and sex. Follow-up covered 22 years from 1995 to 2017. RESULTS: Rates of 'any psychiatric disorder' among siblings compared with control individuals were constantly around twofold increased throughout lifespan whereas there was a bimodal age distribution of hazard ratios of bipolar disorder, unipolar disorder and use of alcohol or psychoactive drugs with the highest hazard ratios up to age 20 and above 60 years of age. Cumulative incidences from age 15 years of any psychiatric disorder were 44.2% at age 80 years for siblings versus 27.6% for control individuals and the corresponding numbers for bipolar disorder was 8.7% for siblings compared with 1.6% for control individuals. CONCLUSION: Strategies to prevent onset of psychiatric illness in individuals with a first-generation family history of bipolar disorder should not be limited to adolescence and early adulthood but should be lifetime, likely with differentiated age-specific strategies.

Spinal pain in pre-adolescence and the relation with screen time and physical activity behavior.

BACKGROUND: To investigate how screen time and physical activity behavior were associated with spinal pain in pre-adolescence. METHODS: This study included 45,555 pre-adolescents who participated in the 11-year follow-up of the Danish National Birth Cohort. The 11-year follow-up included self-reported information on computer and TV behavior, aspects of physical activity, as well as frequency and intensity of spinal pain (neck-, mid back- and low back pain). Data were linked with parental socioeconomic data from Statistics Denmark registers. Associations were estimated using multinomial logistic regression models. To account for sample selection, we applied inverse probability weighting. RESULTS: Duration of screen time was stepwise associated with the degree of spinal pain. Compared with those spending < 2 h/day in front of a screen, screen time of ≥6 h/day was associated with a substantially increased relative risk ratio (RRR) of severe pain for both girls (RRR: 2.49, 95% CI: 2.13-2.92) and boys (RRR: 1.95, 95% CI: 1.65-2.32). Being physical inactive was likewise associated with higher likelihood of severe spinal pain (RRR: 1.22, 95% CI: 1.10-1.34) relative to those being moderately active. We observed that being physically active was seemingly associated with lower risk of spinal pain among boys with high frequency of screen time. CONCLUSION: Findings indicate that both duration of screen time and physical inactivity are correlated with spinal pain in pre-adolescents with the strongest associations for screen time. Reducing screen time or increasing physical activity might help preventing spinal pain in pre-adolescents, particularly among high frequent screen users. Future prospective studies investigating the causal relationship are necessary.

Stress diagnoses in midlife and risk of dementia: a register-based follow-up study.

OBJECTIVES: Previous studies indicated that stress diagnoses increase the risk of dementia. However, previous results may be biased by confounding, reverse causation and misclassification. Therefore, the main aim of this study was to investigate the association between clinically diagnosed stress in midlife and later dementia risk, while addressing limitations of previous studies. METHODS: The study population was selected from all individuals in Denmark born 1935-1956. Individuals diagnosed with stress in midlife (aged 37-58 years) were matched (1:5) with individuals without stress diagnoses based on sex and birthdate (N = 103,484). Data were retrieved from national registers. Cox regression models were adjusted for socio-demographic factors and different morbidities. RESULTS: We found a 2.20 (95% CI: 1.93-2.50) times higher rate of dementia among individuals with any stress diagnosis registered in midlife compared with no stress diagnosis. Hazard rate ratios of dementia were 1.73 (95% CI: 1.13-2.65) among individuals with acute stress reactions, 2.37 (95% CI: 2.05-2.74) among individuals with adjustment disorders, and 2.20 (95% CI: 1.73-2.80) among individuals with unspecified stress reactions. Individuals with PTSD and other stress reactions had non-significantly elevated rates of dementia. Adjustment for confounding only slightly attenuated the association, and reverse causation did not appear to bias the results substantially. CONCLUSION: Our results support the hypothesis that severe stress in midlife is an important risk factor for dementia. This finding emphasizes the importance of identifying and treating severe stress in midlife to reduce potential detrimental consequences for brain health in later life.

Contribution of income and job strain to the association between education and cardiovascular disease in 1.6 million Danish employees.

AIMS: We examined the extent to which associations between education and cardiovascular disease (CVD) morbidity and mortality are attributable to income and work stress. METHODS AND RESULTS: We included all employed Danish residents aged 30-59 years in 2000. Cardiovascular disease morbidity analyses included 1 638 270 individuals, free of cardiometabolic disease (CVD or diabetes). Mortality analyses included 41 944 individuals with cardiometabolic disease. We assessed education and income annually from population registers and work stress, defined as job strain, with a job-exposure matrix. Outcomes were ascertained until 2014 from health registers and risk was estimated using Cox regression. During 10 957 399 (men) and 10 776 516 person-years (women), we identified 51 585 and 24 075 incident CVD cases, respectively. For men with low education, risk of CVD was 1.62 [95% confidence interval (CI) 1.58-1.66] before and 1.46 (95% CI 1.42-1.50) after adjustment for income and job strain (25% reduction). In women, estimates were 1.66 (95% CI 1.61-1.72) and 1.53 (95% CI 1.47-1.58) (21% reduction). Of individuals with cardiometabolic disease, 1736 men (362 234 person-years) and 341 women (179 402 person-years) died from CVD. Education predicted CVD mortality in both sexes. Estimates were reduced with 54% (men) and 33% (women) after adjustment for income and job strain. CONCLUSION: Low education predicted incident CVD in initially healthy individuals and CVD mortality in individuals with prevalent cardiometabolic disease. In men with cardiometabolic disease, income and job strain explained half of the higher CVD mortality in the low education group. In healthy men and in women regardless of cardiometabolic disease, these factors explained 21-33% of the higher CVD morbidity and mortality.

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.

Association Between Neurological Disorders and Death by Suicide in Denmark.

Importance: Neurological disorders have been linked to suicide, but the risk across a broad spectrum of neurological disorders remains to be assessed. Objectives: To examine whether people with neurological disorders die by suicide more often than other people and to assess for temporal associations. Design, Setting, and Participants: Nationwide, retrospective cohort study on all persons 15 years or older living in Denmark, from 1980 through 2016 (N = 7 300 395). Exposures: Medical contact for head injury, stroke, epilepsy, polyneuropathy, diseases of myoneural junction, Parkinson disease, multiple sclerosis, central nervous system infections, meningitis, encephalitis, amyotrophic lateral sclerosis, Huntington disease, dementia, intellectual disability, and other brain diseases from 1977 through 2016 (n = 1 248 252). Main Outcomes and Measures: Death by suicide during 1980-2016. Adjusted incidence rate ratio (IRRs) were estimated using Poisson regressions, adjusted for sociodemographics, comorbidity, psychiatric diagnoses, and self-harm. Results: Of the more than 7.3 million individuals observed over 161 935 233 person-years (49.1% males), 35 483 died by suicide (median duration of follow-up, 23.6 years; interquartile range, 10.0-37.0 years; mean age, 51.9 years; SD, 17.9 years). Of those, 77.4% were males, and 14.7% (n = 5141) were diagnosed with a neurological disorder, equivalent to a suicide rate of 44.0 per 100 000 person-years compared with 20.1 per 100 000 person-years among individuals not diagnosed with a neurological disorder. People diagnosed with a neurological disorder had an adjusted IRR of 1.8 (95% CI, 1.7-1.8) compared with those not diagnosed. The excess adjusted IRRs were 4.9 (95% CI, 3.5-6.9) for amyotrophic lateral sclerosis, 4.9 (95% CI, 3.1-7.7) for Huntington disease, 2.2 (95% CI, 1.9-2.6) for multiple sclerosis, 1.7 (95% CI, 1.6-1.7) for head injury, 1.3 (95% CI, 1.2-1.3) for stroke, and 1.7 (95% CI, 1.6-1.8) for epilepsy. The association varied according to time since diagnosis with an adjusted IRR for 1 to 3 months of 3.1 (95% CI, 2.7-3.6) and for 10 or more years, 1.5 (95% CI, 1.4 to 1.6, P < .001). Compared with those who were not diagnosed with a neurological disorder, those with dementia had a lower overall adjusted IRR of 0.8 (95% CI, 0.7-0.9), which was elevated during the first month after diagnosis to 3.0 (95% CI, 1.9-4.6; P < .001). The absolute risk of suicide for people with Huntington disease was 1.6% (95% CI, 1.0%-2.5%). Conclusions and Relevance: In Denmark from 1980 through 2016, there was a significantly higher rate of suicide among those with a diagnosed neurological disorder than persons not diagnosed with a neurological disorder. However, the absolute risk difference was small.