Danish Register-based Cohort Study Research Articles

Patterns of Antihypertensive Medication Use in the First 2 Years Post Partum.

Women who had a hypertensive disorder of pregnancy (HDP) have a well-documented risk of chronic hypertension within a few years of delivery, but management of postpartum hypertension among these women remains inconsistent. To assess the incidence of initiation of antihypertensive medication use in the first 2 years after delivery by HDP status and antenatal antihypertensive medication use. This Danish register-based cohort study used data from women with at least 1 pregnancy lasting 20 or more gestational weeks (only the first pregnancy in the period was considered) who delivered from January 1, 1995, to December 31, 2018. Statistical analysis was conducted from October 2022 to September 2023. Hypertensive disorders of pregnancy. Cumulative incidences and hazard ratios of initiating antihypertensive medication use within 2 years post partum (5 postpartum time intervals) by HDP status and antenatal medication use. The cohort included 784 782 women, of whom 36 900 (4.7% [95% CI, 4.7%-4.8%]) had an HDP (HDP: median age at delivery, 29.1 years [IQR, 26.1-32.7 years]; no HDP: median age at delivery, 29.0 years [IQR, 25.9-32.3 years]). The 2-year cumulative incidence of initiating postpartum antihypertensive treatment ranged from 1.8% (95% CI, 1.8%-1.8%) among women who had not had HDPs to 44.1% (95% CI, 40.0%-48.2%) among women with severe preeclampsia who required antihypertensive medication during pregnancy. Most women who required postpartum antihypertensive medication after an HDP initiated use within 3 months of delivery (severe preeclampsia, 86.6% [95% CI, 84.6%-89.4%]; preeclampsia, 75.3% [95% CI, 73.8%-76.2%]; and gestational hypertension, 75.1% [95% CI, 72.9%-77.1%]). However, 13.4% (95% CI, 11.9%-14.1%) of women with severe preeclampsia, 24.7.% (95% CI, 24.0%-26.0%) of women with preeclampsia, 24.9% (95% CI, 22.5%-27.5%) of women with gestational hypertension, and 76.7% (95% CI, 76.3%-77.1%) of those without an HDP first filled a prescription for antihypertensive medication more than 3 months after delivery. Women with gestational hypertension had the highest rate of initiating medication after more than 1 year post partum, with 11.6% (95% CI, 10.0%-13.2%) starting treatment after this period. Among women who filled a prescription in the first 3 months post partum, up to 55.9% (95% CI, 46.2%-66.1%) required further prescriptions more than 3 months post partum, depending on HDP status and antenatal medication use. In this cohort study of postpartum women, the incidence of initiation of postnatal antihypertensive medication use varied by HDP status, HDP severity, and antenatal antihypertensive medication use. Up to 24.9% of women initiated antihypertensive medication use more than 3 months after an HDP, with up to 11.6% initiating treatment after 1 year. Routine postpartum blood pressure monitoring might prevent diagnostic delays in initiation of antihypertensive medication use and improve cardiovascular disease prevention among women.

Overweight in childhood and consumer purchases in a Danish cohort.

Prevention and management of childhood overweight involves the entire family. We aimed to investigate purchase patterns in households with at least one member with overweight in childhood by describing expenditure on different food groups. This Danish register-based cohort study included households where at least one member donated receipts concerning consumers purchases in 2019-2021 and at least one member had their Body mass index (BMI) measured in childhood within ten years prior to first purchase. A probability index model was used to evaluate differences in proportion expenditure spent on specific food groups. We identified 737 households that included a member who had a BMI measurement in childhood, 220 with overweight and 517 with underweight or normal weight (reference households). Adjusting for education, income, family type, and urbanization, households with a member who had a BMI classified as overweight in childhood had statistically significant higher probability of spending a larger proportion of expenditure on ready meals 56.29% (95% CI: 51.70;60.78) and sugary drinks 55.98% (95% CI: 51.63;60.23). Conversely, they had a statistically significant lower probability of spending a larger proportion expenditure on vegetables 38.44% (95% CI: 34.09;42.99), compared to the reference households. Households with a member with BMI classified as overweight in childhood spent more on unhealthy foods and less on vegetables, compared to the reference households. This study highlights the need for household/family-oriented nutrition education and intervention.

Duration and timing of depression and risk of family dissolution: A register-based cohort study of newly-formed Danish families

BackgroundDepression is detrimental to partnership stability. However, it remains unclear if and how the duration and timing of depression affect the risk of family dissolution. MethodsWe conducted a Danish register-based cohort study of newly-formed cohabiting and married couples in 2008 and 2009, who were followed from the second year after family formation. Depressive episodes were defined by individual-level prescription patterns of antidepressant drugs (ATC codes N06A) in either partner. Family dissolution was characterized by the discontinuation of a shared residential address. Using Longitudinal Targeted Minimum Loss-based Estimation, we estimated the risk of family dissolution after 5 years of follow-up under various lengths and timings of depressive episodes. ResultsThere were 102,335 families included. The covariate-adjusted risk of family dissolution in families without depressive episodes was 30.0 % (95 % CI 29.6–30.4 %) and 35.5 % (95 % CI 29.5–41.5 %) in families with at least one depressive episode during follow-up. The risk of family dissolution increased with the duration of depressive episodes to 42.2 % (95 % CI 40.8–43.6 %) for five coherent years of depression. Depression shortly after family formation carried higher risk of family dissolution; this risk was 42.3 % (95 % CI 38.4–46.3 %) for depression experienced in the first year of family formation versus 32.9 % (95 % CI 31.8–34.0 %) in the fifth year of family formation. LimitationsProxy measures of depression by antidepressant prescriptions fails to identify milder depression. Annual measures of family dissolution precluded more fine-grained analyses of time-intervals. ConclusionsDepression is disruptive to family stability, particularly with longer duration and early onset after family formation.

The interplay between the impact of household's and children's education on the risk of type 2 diabetes and death among older adults: a Danish register-based cohort study

ObjectivesThis study aims to assess the association of household's and children's education on the risk of type 2 diabetes (T2D) and subsequent death. Study designDanish register-based cohort study. MethodsIn total, 1,021,557 adults were included at their 65th birthday between 2000 and 2018. A multistate survival model was performed to estimate the association of household's and children's education on the transition between the three states: 1) 65th birthday; 2) diagnosis of T2D; and 3) all-cause death. ResultsThe incidence rates per 1000 person-years were 9.1 for T2D, 18.4 for death without T2D, and 45.0 for death with T2D. Compared to long household's education and children's education, long household's education combined with either short-medium children's education or no children were associated with a 1.49- (95% confidence interval [CI]: 1.44; 1.54] and 1.69-times (95% CI: 1.61;1.78) higher hazard of T2D, respectively. Short-medium household's education combined with either long children's education or no children were associated with 0.64- (95% CI: 0.62; 0.66) and 0.77-times (95% CI: 0.74; 0.79) lower hazard of T2D, respectively. Compared to long household's education and children's education, any other combination of household's and children's education was associated with higher hazards of death both without and with T2D. ConclusionOlder adults living in households with long education with no children or children with short-medium education had higher hazards of T2D. Households with short-medium education and no children or children with long education were associated with lower hazards of T2D. Both household's and children's education were associated with higher hazard of death without and with T2D.

Symptom-Specific Hospital Contacts in 12-18-Year-Olds Vaccinated against COVID-19: A Danish Register-Based Cohort Study.

In this register-based real-life cohort study, changes in symptom-specific hospital contacts among 12-18-year-olds following two doses of the BNT162b2 COVID-19 vaccine compared to unvaccinated peers were investigated. Using national register data, vaccinated and unvaccinated adolescents were sex and age-matched each week during the inclusion period from May to September 2021. Symptom-specific hospital contacts covering ICD-10 R diagnoses were assessed before first the vaccine dose and after the second vaccine dose. Taking previous rates of symptom-specific hospital contacts into account, differences between vaccinated and unvaccinated adolescents were found. For some hospital contacts, higher rates were seen among the vaccinated, and for others, higher rates were seen among the unvaccinated. Unspecific cognition symptoms may be important to monitor in vaccinated girls, and likewise for throat and chest pain in vaccinated boys within the first months post-vaccination. In perspective, symptom-specific hospital contacts after vaccination against COVID-19 must be assessed by taking the risk of infection and symptoms following COVID-19 infection into account.

Persistence and adherence with Latanoprost: A Danish register-based cohort study in older patients with glaucoma.

This study aims to assess the association between switching patterns and adherence/persistence in Danish patients over the age of 65, who started their first-ever glaucoma treatment with latanoprost eye drops. Patients were assigned to three different cohorts: (1) switchers, (2) non-switchers, and (3) preservative-free latanoprost (Monoprost®) users. Patients were followed for 1 year until the end of data coverage or censoring. Study covariates were used to compute the propensity score. In the adjusted analysis, the propensity score was added to the model as an independent variable. The Cox regression model was used to calculate the hazard ratio (HR) of discontinuation for the three cohorts (the non-switchers cohort was the reference level) in both adjusted and unadjusted analyses. Non-switchers had a statistically significant lower adherence (proportion of days covered, PDC 92%) than switchers (PDC 96%; p < 0.001) and users of Monoprost® (PDC 99%; p < 0.001). Switchers had a 53% lower risk of treatment discontinuation compared to the reference group within 1 year after the first redemption of latanoprost in both unadjusted (HR 0.47; 95% Confidence interval, 95% CI: 0.41-0.53; p < 0.001) and adjusted (HR 0.47; 95% CI: 0.42-0.53; p < 0.001) analyses. In comparison to the non-switchers, Monoprost® users had a 78% lower risk for the above result in both unadjusted (HR 0.22; 95% CI: 0.17-0.28; p < 0.001) and adjusted (HR 0.22; 95% CI: 0.17-0.29; p < 0.001) analyses. This study found increased adherence and persistence in latanoprost users among those who redeemed preservative-free latanoprost (Monoprost®) and among those who switched between different latanoprost formulations.

Association between cannabis use disorder and schizophrenia stronger in young males than in females.

Previous research suggests an increase in schizophrenia population attributable risk fraction (PARF) for cannabis use disorder (CUD). However, sex and age variations in CUD and schizophrenia suggest the importance of examining differences in PARFs in sex and age subgroups. We conducted a nationwide Danish register-based cohort study including all individuals aged 16-49 at some point during 1972-2021. CUD and schizophrenia status was obtained from the registers. Hazard ratios (HR), incidence risk ratios (IRR), and PARFs were estimated. Joinpoint analyses were applied to sex-specific PARFs. We examined 6 907 859 individuals with 45 327 cases of incident schizophrenia during follow-up across 129 521 260 person-years. The overall adjusted HR (aHR) for CUD on schizophrenia was slightly higher among males (aHR = 2.42, 95% CI 2.33-2.52) than females (aHR = 2.02, 95% CI 1.89-2.17); however, among 16-20-year-olds, the adjusted IRR (aIRR) for males was more than twice that for females (males: aIRR = 3.84, 95% CI 3.43-4.29; females: aIRR = 1.81, 95% CI 1.53-2.15). During 1972-2021, the annual average percentage change in PARFs for CUD in schizophrenia incidence was 4.8 among males (95% CI 4.3-5.3; p < 0.0001) and 3.2 among females (95% CI 2.5-3.8; p < 0.0001). In 2021, among males, PARF was 15%; among females, it was around 4%. Young males might be particularly susceptible to the effects of cannabis on schizophrenia. At a population level, assuming causality, one-fifth of cases of schizophrenia among young males might be prevented by averting CUD. Results highlight the importance of early detection and treatment of CUD and policy decisions regarding cannabis use and access, particularly for 16-25-year-olds.

Predictors of transfer and prognosis after transfer from child and adolescent mental health services to adult mental health services-a Danish nationwide prospective register-based cohort study.

Onset of mental health disorder peaks during adolescence making continuity of care during this period of life crucial both to ensure a smooth treatment course and high quality of mental health services for adolescents. We aimed to examine which clinical and sociodemographic features predict transfer from child and adolescent mental health services to adult mental health services and if transfer is associated with prognosis. A Danish register study including all 16-17-year-olds with an outpatient contact in child and adolescent mental health services, who were discharged in the period of 1/1/06-10/05/15. Out of 27,170 Danish adolescents, 16% transferred to adult mental health services. Transfer was predicted by schizophrenia (OR 6.16; 95% CI 5.51-6.90) and personality disorders (OR 2.08; 95% CI 1.84-2.34), while hyperkinetic (OR 0.54; 95% CI 0.49-0.59) and pervasive developmental disorders (OR 0.42; 95% CI 0.31-0.58) decreased likelihood of transfer. Transfer was also substantially predicted by inpatient admission (OR 3.37; 95% CI 3.14-3.61) and psychiatric medication (OR 2.07; 95% CI 1.92-2.23). Transfer was associated with higher rates of inpatient admission to adult mental health services (IRR 5.83; 95% CI 4.37-7.77), more psychiatric emergency contacts (IRR 12.0; 95% CI 10.7-13.4), more convictions (IRR 1.40; 95% CI 1.23-1.59) and suicide attempts (IRR 5.70; 95% CI 4.72-6.90). Policy-makers and clinicians should push for improvements and open a discussion of how to ensure continuity of care for adolescents with psychiatric disorders.

Joint exposure to parental cancer and income loss during childhood and the child’s socioeconomic position in early adulthood: a Danish and Norwegian register-based cohort study

BackgroundParental cancer as well as economic hardship in the family during childhood can affect the child negatively. Our aim was to examine the association between the joint exposure to parental...

Cancer Risk following Residential Exposure to Airborne Polychlorinated Biphenyls: A Danish Register-Based Cohort Study.

Background:Polychlorinated biphenyls (PCBs) are biopersistent chemicals classified as human carcinogens. This classification is primarily based on evidence on higher-chlorinated PCBs found in food. The carcinogenic potential of airborne lower-chlorinated PCBs remains largely unexplored.Objectives:We aimed to investigate cancer risk following residential exposure to airborne PCBs.Methods:Cancer risk was examined in the Health Effects of PCBs in Indoor Air (HESPAIR) cohort of 38,613 residents of two partly PCB-contaminated residential areas in Greater Copenhagen, identified by nationwide registries. PCB exposure was based on relocation dates and indoor air PCB measurements in subsets of apartments. Cancer diagnoses were extracted from the Danish Cancer Registry for the follow-up period of 1970–2018. We estimated adjusted hazard ratios with time-varying cumulative exposure and a 10-y lag using Cox regression.Results:Overall risk of cancer was not associated with , [hazard ratio (HR) for high-exposed vs. low-exposed ; 95% confidence interval (CI): 0.88, 1.09], but residents exposed to had higher risk of liver cancer (HR ; 95% CI: 1.28, 6.15) and meningiomas (HR ; 95% CI: 1.84, 6.64), with indications of exposure–response relationships. Results were suggestive of a higher risk of pancreatic cancer (HR ; 95% CI: 0.95, 2.64) at the highest aggregated PCB level. For testis cancer, a higher risk was observed among residents exposed to relative to residents exposed to (HR ; 95% CI: 1.41, 6.28), but the risk was not higher for residents exposed to . Apart from this, the risk of specific cancers was similar across exposure groups.Discussion:In this, to our knowledge, first population-based cohort study of residential exposure to airborne PCBs, we found no association between exposure to PCBs in indoor air in private homes and the risk for most of the specific cancers. Higher risk of liver cancer and meningiomas were observed. https://doi.org/10.1289/EHP10605

Electroconvulsive Therapy and Risk of Road Traffic Accidents: A Danish Register-Based Cohort Study.

The aim of the study is to examine whether electroconvulsive therapy (ECT) was associated with the subsequent risk of being involved in a road traffic accident. A cohort of all 375,435 patients older than 18 years with their first psychiatric hospital contact between 2003 and 2017 in the Danish National Patient Registry was followed for road traffic accidents until December 2018. Associations between ECT and road traffic accidents were examined using Cox regression analyses with multiple adjustments and using propensity score matching on sociodemographic and clinical variables. A total of 8486 patients (0.2%) were treated with ECT. During the median follow-up of 5.9 years, 778 of these patients (12.5%) were involved in a road traffic accident and the unadjusted incidence of road traffic accidents was lower among these patients (incidence rate, 15.5 per 1000 patient-years; 95% confidence interval [CI], 14.5-16.7) compared with patients not treated with ECT (incidence rate, 20.0 per 1000 patient-years; 95% CI, 20.0-20.3). Electroconvulsive therapy was not associated with road traffic accidents in the Cox regression models after adjustment for all covariables (hazard ratio, 1.00; 95% CI, 0.92-1.08) or in the propensity score-matched sample (hazard ratio, 0.91; 95% CI, 0.83-1.08). The HRs did not vary materially with follow-up time or when analyses were stratified on sex, age, or type of hospital contact. The analysis of Danish National registry data indicates that ECT is not associated with the risk of being involved in major road traffic accidents.

Temporally ordered associations between type 2 diabetes and brain disorders – a Danish register-based cohort study

BackgroundType 2 diabetes mellitus (T2DM) is linked with several neurodegenerative and psychiatric disorders, either as a comorbid condition or as a risk factor. We aimed to expand the evidence by examining associations with a broad range of brain disorders (psychiatric and neurological disorders, excluding late-onset neurodegenerative disorders), while also accounting for the temporal order of T2DM and these brain disorders.MethodsIn a population-based cohort-study of 1,883,198 Danish citizens, born 1955–1984 and followed until end of 2016, we estimated associations between T2DM and 16 brain disorders first diagnosed between childhood and mid-adulthood. We calculated odds ratios (OR) and hazard ratios (HR) with 95% confidence intervals (CI) in temporally ordered analyses (brain disorder diagnosis after T2DM and vice versa), adjusted for sex, age, follow-up, birth year, and parental factors.ResultsA total of 67,660 (3.6%) of the study population were identified as T2DM cases after age 30 and by a mean age of 45 years (SD of 8 years). T2DM was associated with most psychiatric disorders. Strongest associations were seen with other (i.e. non-anorectic) eating disorders (OR [95% CI]: 2.64 [2.36–2.94]) and schizophrenia spectrum disorder (2.73 [2.63–2.84]). Among neurological disorders especially inflammatory brain diseases (1.73 [1.57–1.91]) and epilepsy (1.67 [1.60–1.75]) were associated with T2DM. Most associations remained in both directions in the temporally ordered analyses. For most psychiatric disorders, associations were strongest in females.ConclusionsT2DM was associated with several psychiatric and neurological disorders, and most associations were consistently found for both temporal order of disorders. This suggests a shared etiology of T2DM and those brain disorders. This study can form the starting point for studies directed at further elucidating potential causal links between disorders and shared biological mechanisms.

Diabetes, sleep disorders and risk of depression - A Danish register-based cohort study

AimsWe examined the influence of comorbid sleep disorder on the association between type 2 diabetes (T2D) and risk of incident depression. MethodsThe study population (N = 232,489) was based on all individuals registered aged ≥40 years with a T2D diagnosis between January 1, 2000 to December 31, 2012 in the Danish National Diabetes Register and a matched reference population. The risk of incident depression (diagnosis or anti-depressant medication) following T2D and possible effect modification of comorbid sleep disorder was estimated using adjusted Cox proportional hazards regression. Sleep disorder was defined as a diagnosis of insomnia, hypersomnia or sleep-wake schedule disorders or use of sleep medication (z-drugs or melatonin) in the Danish National Patient Registry or the Danish National Prescription Registry. ResultsAt study entry, 15.3 % of the participants had a sleep disorder. During follow-up, 2.6 % were diagnosed with depression and 32.1 % received antidepressant medication. The unadjusted hazard ratio (HR) for depression was 1.54 (95%CI 1.52–1.56) for patients with diabetes, which attenuated to 1.50 (1.48–1.52) after adjustment for sleep disorders, which further attenuated to 1.27 (1.26–1.29) in the model further adjusted for psychiatric and somatic comorbidities. The analyses of T2D and sleep disorder as independent and combined variables compared with none of the conditions on risk of depression, showed a HR of 1.27 (95 % CI 1.19–1.35) for T2D without sleep disorder, 1.46 (95 % CI 1.33–1.59) for sleep disorders without T2D, and 1.49 (95%CI 1.37–1.63) for both conditions. ConclusionsT2D and sleep disorders were independently associated with subsequent risk of depression and individuals with both conditions experienced the greatest relative risk. Sleep disorders neither explained nor amplified the relation between diabetes and depression.

Investigation of the potential association between the use of fluoxetine and occurrence of acute pancreatitis: a Danish register-based cohort study.

BackgroundThere is currently conflicting evidence of the association between the use of selective serotonin reuptake inhibitors (SSRIs) and acute pancreatitis. The SSRI fluoxetine has been suspected to be the driver of this serious outcome. Therefore, this study aims to investigate the potential association between fluoxetine use and the occurrence of acute pancreatitis.MethodsWe conducted a nationwide cohort study using Danish register-based data from 1996 to 2016. The exposed group were new users of fluoxetine (1-year washout). The control subjects were new users of citalopram or SSRIs, excluding fluoxetine. The outcome was an incident diagnosis of acute pancreatitis with a 5-year washout. We used an intention-to-treat approach following patients for a maximum of 6 months. Cox regression analyses were performed, estimating hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for age/sex, comorbidities and co-medications, using propensity score adjustment and matching.ResultsIn the propensity score-matched analyses, 61 783 fluoxetine users were included. The incidence rates among users of fluoxetine and other SSRIs were 5.33 (3.05–8.66) and 5.36 (3.06–8.70) per 10 000 person-years, respectively. No increased risk of acute pancreatitis was identified following fluoxetine exposure compared with either citalopram [HR 1.00, 95% CI 0.50–2.00) or other SSRIs (0.76, 0.40–1.46).ConclusionsFluoxetine use was not associated with an increased risk of acute pancreatitis compared with citalopram or other SSRIs. The absolute risk of acute pancreatitis was low and did not vary between different SSRIs. Further research is needed to determine whether there is a class effect on the risk of acute pancreatitis.

Geographical inequalities in the decreasing 28-day mortality following incident acute myocardial infarction: a Danish register-based cohort study, 1987\u20132016

BackgroundMortality following acute myocardial infarction (AMI) has decreased in western countries for decades; however, it remains unknown whether the decrease is distributed equally across the population independently of residential location. This study investigated whether the observed decreasing 28-day mortality following an incident AMI in Denmark from 1987 to 2016 varied geographically at municipality level after accounting for sociodemographic characteristics.MethodsA register-based cohort study design was used to investigate 28-day mortality among individuals with an incident AMI. Global spatial autocorrelation (within sub-periods) was analysed at municipality level using Moran's I. Analysis of spatio-temporal autocorrelation before and after adjusting for sociodemographic characteristics was performed using logistic regression and conditional autoregressive models with inference in a Bayesian setting.ResultsIn total, 368,839 individuals with incident AMI were registered between 1987 and 2016 in Denmark; 128,957 incident AMIs were fatal. The 28-day mortality decreased over time at national level with an odds ratio of 0.788 (95% credible interval (0.784, 0.792)) per 5-year period after adjusting for sociodemographic characteristics. The decrease in the 28-day mortality was geographically unequally distributed across the country and in a geographical region in northern Jutland, the 28-day mortality decreased significantly slower (4–12%) than at national level.ConclusionsDuring the period from 1987 to 2016, the 28-day mortality following an incident AMI decreased substantially in Denmark. However, in a local geographical region, the 28-day mortality decreased significantly slower than in the rest of the country both before and after adjusting for sociodemographic differences. Efforts should be made to keep geographical trend inequalities in the 28-day mortality to a minimum.

Depression in adulthood and risk of dementia later in life: A Danish register-based cohort study of 595,828 men

BackgroundAssociations between depression and dementia could express a causal relationship, reverse causality or be explained by health-related factors. This study explores the association of depression and indicators of depression severity with subsequent risk of dementia while ensuring temporality and adjusting for important health-related factors. Method595,828 men from the Danish Conscription Database born in 1939-59 with register-based information on lifetime depression and covariates at age 55 years were followed in nationwide registers to identify dementia cases until 2016. Associations were analyzed using Cox proportional hazard regression models with adjustment for intelligence, education level, body mass index, and comorbidities. ResultsThe dementia incidence per 1000 person-years was 1.2 cases for men without prior depression and 2.1 and 3.6 cases for men who had depression identified by antidepressants and hospitalization, respectively. Compared to no prior depression, depression identified by antidepressant medication was associated with 1.94 times [95% confidence interval (CI) 1.81;2.07] higher hazard of dementia and depression identified by hospitalization with depression was associated with 2.18 [95% CI: 1.95;2.45] higher hazard of dementia. Long-term course of depression identified by antidepressant prescriptions (>20 prescriptions), was associated with 40% 95% CI: 1.23;1.59 higher hazard of dementia compared to having ≤10 prescriptions. LimitationsThis study is restricted to men and dementia cases until age 57-77 years. ConclusionMen with depression before late midlife are subject to a higher risk of dementia later in life. Clinicians should be aware of dementia symptoms in patients with a long history of depression to initiate early treatment.

Osteoarthritis in osteogenesis imperfecta: A nationwide register-based cohort study.

Osteogenesis Imperfecta (OI) is a genetic disease characterized by skeletal fragility. Collagen type 1 is found in many tissues and collagen abnormalities may result in organ specific symptomatology. Musculoskeletal pain is a known issue for patients with OI, osteoarthritis (OA) can be a likely cause. Only few studies have investigated the relationship between OI and OA but demonstrated a greater propensity in OI patients to develop rapidly progressing OA. Therefore, we wanted to investigate if OA is more frequent in patients with OI compared to the general population. To evaluate the risk of osteoarthritis in patients with OI. A Danish nationwide, population-based and register-based longitudinal open cohort study. From 1977 to 2019, all patients registered with an OI diagnosis and a reference population matched on age and sex 5:1. Sub-hazard ratios for any, hip, and knee osteoarthritis comparing the OI cohort to the reference population. We identified 907 patients with OI (493 women) and included 4535 patients in the reference population (2465 women). The Sub Hazard Ratio was 2.20 [95% CI 1.73-2.79] for any osteoarthritis with 11.4% of the OI population and 5.4% of the reference population being registered. We found lower incidences of upper extremity joint OA compared to lower joint OA, but upper extremity joint OA was significantly more frequent in the OI population 2.1% vs 0.6%, SHR 3.19 [95% CI 1.78-5.70]. Patients with OI have a higher risk of OA than the reference population. Osteogenesis Imperfecta (OI) is a hereditary connective tissue disorder with skeletal fragility and extraskeletal manifestations. Osteoarthritis is a frequent joint disease and the incidence increases with age. In a population-register-based study, the risk of osteoarthritis was higher in patients with OI at an earlier age compared to a reference population.

P.0098 Number of traumatic brain injuries and temporal associations with depression: A Danish register-based cohort study

P.0098 Number of traumatic brain injuries and temporal associations with depression: A Danish register-based cohort study

Involuntary treatment in patients with anorexia nervosa: utilization patterns and associated factors.

A subgroup of patients with anorexia nervosa (AN) undergoing involuntary treatment (IT) seems to account for most of the IT events. Little is known about these patients and their treatment including the temporal distribution of IT events and factors associated with subsequent utilization of IT. Hence, this study explores (1) utilization patterns of IT events, and (2) factors associated with subsequent utilization of IT in patients with AN. In this nationwide Danish register-based retrospective exploratory cohort study patients were identified from their first (index) hospital admission with an AN diagnosis and followed up for 5 years. We explored data on IT events including estimated yearly and total 5-year rates, and factors associated with subsequent increased IT rates and restraint, using regression analyses and descriptive statistics. IT utilization peaked in the initial few years starting at or following the index admission. A small percentage (1.0%) of patients accounted for 67% of all IT events. The most frequent measures reported were mechanical and physical restraint. Factors associated with subsequent increased IT utilization were female sex, lower age, previous admissions with psychiatric disorders before index admission, and IT related to those admissions. Factors associated with subsequent restraint were lower age, previous admissions with psychiatric disorders, and IT related to these. High IT utilization in a small percentage of individuals with AN is concerning and can lead to adverse treatment experiences. Exploring alternative approaches to treatment that reduce the need for IT is an important focus for future research.

307Association between patterns of comorbid mental disorders and mortality-related estimates. A Danish register-based cohort study

Abstract Background Comorbidity within mental disorders is common, and people with two or more types of mental disorders have shorter life expectancy compared to those with exactly one type. The aims of this study were to: (a) describe the prevalence of combinations of mental disorders; and (b) estimate the excess mortality for each of these combinations. Methods We conducted a population-based cohort study including all 7,505,576 persons living in Denmark in 1995-2016. Using national registers, we described the most common combinations of mental disorders and investigated excess mortality by means of mortality rate ratios (MRRs) and differences in life expectancy. Results At the end of the 22-year observation, 6.2% individuals were diagnosed with exactly one disorder, and 5.3% with two or more types. People with any combination of disorders had higher mortality rates than those without any diagnosis (MRRs ranging from 1.10 [95% CI 0.67 – 1.84] to 5.97 [95% CI 5.52 – 6.45]) and shorter life expectancies compared to the general population (estimates ranging from 5.06 years [95% CI 5.01 – 5.11] to 17.46 years [95% CI 16.86 – 18.03]). Conclusions Mood disorders and neurotic disorders commonly co-occur, and contribute to many different sets of comorbid mental disorders. The association between mental disorders comorbidity and mortality revealed the prominent role of substance use disorders. Key messages Our study provides prevalence estimates of the most common sets of mental disorders. In light of the substantial contribution of substance use disorders to premature mortality, efforts related to the ‘primary prevention of secondary comorbidity’ warrant added scrutiny.