Studies of Suicidal Behavior Using National Registers

Nordic region suicide trends 2000-2018; sex and age groups

BACKGROUND AND AIM

Overall, suicide rates in the Nordic region, Denmark, Finland, Iceland, Norway and Sweden, have declined in the past 40 years. The aim of this study was to determine trends in suicide mortality from 2000 to 2018.

METHODS

Data were obtained from official suicide statistics for men and women, 15 years and older. Gender and age groups in four calendar periods were analyzed using Joinpoint Estimated Regression Coefficient.

RESULTS

The crude regional suicide rate was 17.1, 2000-2004, decreased to 14.1 per 100,000 inhabitants in 2015-2018. Age-standardized rates are 13.6-11.3. The crude rate decreased by 19.5% (16.3% age-standardized), 19.3% for males and 20.5% for females. The largest decrease was found in Finland (34.9%), the smallest in Norway (1.4%). In males, the exception was an increased suicide rate among all Icelandic except 15-24-year olds, and in 45-64 year-old Norwegians. Among females, an increase was seen among 15-24-year olds in all countries except Iceland, in all age groups in Norway, and in 25-44-year olds in Sweden. In males, a decline of the suicide rated lower than 10% was noted in 25-44 olds in Norway and in 15-64 year-olds in Sweden.

DISCUSSION

A robust decrease was observed in the overall regional suicide rate in recent years. Exceptions are rising rates in Icelandic males, in Norwegian females, and the youngest female groups in all except Iceland. The small decline among middle-aged males in Norway and Sweden is of concern.

Suicide in services for mental health and substance use: A national hybrid registry surveillance system

Suicide is strongly associated with mental health and substance use disorders, which makes mental health- and substance misuse services important areas for suicide prevention. The aim of The Norwegian Surveillance System for Suicide in Mental Health and Substance Use Services is to describe all suicide deaths in Norway that occur within one year after contact with mental health and substance misuse services. The study uses a hybrid registry case series design. It consists of a yearly linkage between the Norwegian Cause of Death Registry and the Norwegian Patient Registry, which is linked with a questionnaire. The linkage is conducted by using a cryptographic hash function of the deceased's personal id, thus ensuring that the project can link data across sources without the use of directly identifiable information. This indirect linkage ensures the deceased's confidentiality. Moreover, the The Norwegian Surveillance System for Suicide shows how administratively collected data can be harnessed and used for surveillance. Both use of hybrid registry designs and linkage through cryptographic hash functions might contribute to the development of health informatics as well as quality improvement in health care.

Parental death by external causes and risk of hospital-treated deliberate self-harm in bereaved offspring

Previous studies have reported an increased risk of hospital-treated deliberate self-harm (DSH) in offspring who have lost a parent, but inconclusive findings regarding differences between loss from suicide and accidents. The present study aimed to investigate the association between parental death by external causes before age 18 and hospital-treated DSH, and potential differences between different accidents and suicide. This nested-case-control study was based on data from longitudinal Norwegian registers. Subjects comprised 12,526 people born between 1970 and 2003 who received acute somatic treatment because of DSH at hospitals and associated services between 2008 and 2013 (cases), and 222,362 controls matched for gender and date of birth with no recorded DSH treatment. Information concerning deceased parent's death and offspring's DSH treatment and socioeconomic data was merged. Data were analysed with conditional logistic regression. Results indicated that offspring who had lost a parent to suicide (OR 2.32, 95% CI 1.92-2.80) and death by accidents such as falls, poisoning, and drowning (OR 1.79, 95% CI 1.38-2.33) had a significantly increased risk of hospital-treated DSH compared to offspring who had not experienced such loss. Parental bereavement from transport accidents and other external causes were not associated with significantly increased risks. No differences were evident for different genders of deceased, ages at bereavement, or genders of bereaved. The improved identification of bereaved offspring at particular risk of hospital-treated DSH should be utilized to implement effective prevention and treatment programs in specialist healthcare aimed at the individuals at highest risk.

Examining the Use of Police and Ambulance Data in Suicide Research

Background: Police and paramedics are often the first to respond to individuals in suicide crisis and have an important role to play in facilitating optimal care pathways. Yet, little evidence exists to inform these responses. Data linkage provides one approach to examining this knowledge gap. Aim: We identified studies that examined suicide behaviors and linked to police or ambulance data. Method: A systematic search of PubMed and Scopus was undertaken to identify data linkage studies that: (1) examined suicide behaviors, and (2) included police or ambulance data. Studies were reviewed to identify: aims; suicide behaviors examined; how these were measured; how the cohort was defined; topic area; and what datasets were linked. Results: Eight studies met the inclusion criteria. Six studies included police data, and two studies included ambulance data. No study included both. Two topic areas were identified: (1) suicide-related contact with police or ambulance services; and (2) associations between suicidal behaviors and violence, victimization, and criminality. Limitations: Limitations to the review include the potential to have missed studies that investigated or reported on suicidality under the guise of mental health problems; complexities and nuances arising from the role of police data in coronial investigations; and limitations in the number of databases searched. Conclusion: Police and ambulance data represent a currently underutilized source of valuable information relevant to suicide crises, and further research should aim to address this gap.

Work related sexual harassment and risk of suicide and suicide attempts: prospective cohort study

OBJECTIVE

To analyse the relation between exposure to workplace sexual harassment and suicide, as well as suicide attempts.

DESIGN

Prospective cohort study.

SETTING

Sweden.

PARTICIPANTS

86 451 men and women of working age in paid work across different occupations responded to a self-report questionnaire including exposure to work related sexual harassment between 1995 and 2013. The analytical sample included 85 205 people with valid data on sexual harassment, follow-up time, and age.

MAIN OUTCOME MEASURES

Suicide and suicide attempts ascertained from administrative registers (mean follow-up time 13 years).

RESULTS

Among the people included in the respective analyses of suicide and suicide attempts, 125 (0.1%) died from suicide and 816 (1%) had a suicide attempt during follow-up (rate 0.1 and 0.8 cases per 1000 person years). Overall, 11 of 4095 participants exposed to workplace sexual harassment and 114 of 81 110 unexposed participants committed suicide, and 61/4043 exposed and 755/80 513 unexposed participants had a record of suicide attempt. In Cox regression analyses adjusted for a range of sociodemographic characteristics, workplace sexual harassment was associated with an excess risk of both suicide (hazard ratio 2.82, 95% confidence interval 1.49 to 5.34) and suicide attempts (1.59, 1.21 to 2.08), and risk estimates remained significantly increased after adjustment for baseline health and certain work characteristics. No obvious differences between men and women were found.

CONCLUSIONS

The results support the hypothesis that workplace sexual harassment is prospectively associated with suicidal behaviour. This suggests that suicide prevention considering the social work environment may be useful. More research is, however, needed to determine causality, risk factors for workplace sexual harassment, and explanations for an association between work related sexual harassment and suicidal behaviour.

Suicides in Mood Disorders in Psychiatric Settings in Nordic National Register-Based Studies

OBJECTIVE

Although risk factors for nonfatal suicidal behavior in mood disorders have been vastly investigated, rate and risk factors of suicide deaths are less well known. Extensive health care and other population registers in the Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden) allow national-level studies of suicide rates and risk factors. This systematic review examined Nordic studies of suicide in mood disorders.

METHODS

National Nordic studies published after 1.1.2000 reporting on suicide mortality or relative risk in diagnosed unipolar depression or bipolar disorder treated in psychiatric settings; temporal variations in suicide risk after discharge, or risk factors for suicide were systematically reviewed.

RESULTS

Altogether 16 longitudinal studies reported on rate and risk of suicide in depression. They found 2%-8% of psychiatric inpatients with depression to have died by suicide. However, in Finland suicide risk among depressive inpatients halved since the early 1990s. Nine studies investigated suicide risk in bipolar disorder, finding 4-8% of patients having died by suicide in long term. The relative risk of suicide was consistently found extremely high (SMR > 100) during the first weeks postdischarge, declining steeply over time to approximately SMR of five after five years. Male gender, preceding suicide attempts, high severity of depression and substance abuse were found risk factors for suicide in depression, with only minor gender differences in risk factors, but major differences in lethal methods. Three studies investigated risk factors for suicide in bipolar disorder, finding male gender, preceding suicide attempts, and depressive episodes and psychiatric comorbidity to be associated with risk.

CONCLUSIONS

Overall, of psychiatric inpatients with depressive of bipolar disorders in the Nordic countries, 2%-8% have died by suicide in the last few decades, but current rates may be lower. Suicide risk is approximately similar or somewhat higher among patients with bipolar disorder, risk factor studies of whom are fewer. Risk of suicide is remarkably high immediately after discharge, and higher among males than females, those with preceding suicide attempts, high severity of depression, or concurrent substance abuse. Generalizability of findings from these Nordic studies to other countries need to be investigated, and their methodological limitations understood.

Educational attainment in offspring bereaved by sudden parental death from external causes: a national cohort study from birth and throughout adulthood

PURPOSE

Previous research has linked loss of a parent during childhood to reduced educational aspirations, school performance, and educational attainment later in life. The potential effect of maternal and paternal bereavement on attainment at all educational levels is, however, unknown. The present study aimed to investigate the potential influence of parental death by external causes on completion of compulsory education, high school, vocational education, and University or College education.

METHODS

The study was based on data from three national longitudinal registers in Norway. The study population comprised 373,104 individuals born between January 1st 1970 and December 31st 1994. Information concerning deceased parents' cause and date of death and offspring's education and sociodemographic data were retrieved. Data were analysed with Cox regression.

RESULTS

Children who had experienced parental death by external causes had a significantly reduced hazard ratio (HR) of completing all educational levels compared to children who did not have such experiences. The largest effects were evident for completion of high school (HR 0.68, 95% CI 0.65-0.71) and University or College education (HR 0.75, 95% CI 0.70-0.80). No differences were evident for different causes of death, genders of deceased or ages at bereavement, and generally no significant interactions between gender of the bereaved offspring and predictor variables were evident for completion of all educational levels.

CONCLUSION

Parental death by external causes has vast and long-lasting impacts on offspring's educational attainment at all levels. Health care interventions aimed at supporting bereaved children and adolescents should focus on challenges related to educational progress.

Deliberate self-harm: Case identification and incidence estimate upon data from national patient registry

BACKGROUND

Patient registry is a valuable source for identification of deliberate self-harm (DSH) incidents on a population basis; however, little research has provided sufficient details that could inform best utilization of this complicated data source for DSH research and statistics. In this study we want to use data from the Norwegian Patient Register to delineate a diagnostic coding system to identify medically treated DSH incidents, to profile general characteristics of these incidents, and to estimate incidence rate of DSHs in the national population of Norway.

METHODS

We obtained all records of patient contacts to somatic hospitals and emergency centers due to external causes from 2008 through 2013. For each contact, we retrieved clinical data on primary and comorbid diagnoses, urgency of contact, etc., alongside with personal general information. After careful mining, the data were further processed following a multi-step analytic strategy. Descriptive analysis was used to profile DSH incidents and to estimate incidence rates and corresponding 95% confidence intervals.

FINDINGS

From 1 459 384 eligible incident contacts for emergency injury treatment, we identified 13 533 incidents that had a recorded diagnosis of DSH, i.e., with a supplemental code of X6n. Upon delineation of these recorded DSHs, we devised a diagnostic coding system to identify all possible DSH incidents. This yielded a total of 38 433 incidents to be considered as likely incidents of DSH (adjusted incidents)-a number that is 2.84 times higher than that of the recorded DSH incidents during the study period. While the proposed diagnostic system captured more incidents by males and old adults, the adjusted DSHs remained more common in females than males, and occurred most frequently within young people of 18-21 years. These incidents imply about 6400 DSH incidents from 5100 persons per year and correspond to a yearly cumulative incidence rate of 121.0 (95% CI: 113.4-128.2) per 100000 population over 10 years old with particularly high rates in teenage girls of 15-19 years old (296.1/100000) and females and males of 20-24 years old (282.5 and 178.8/100000, respectively).

CONCLUSION

The insightful details of data processing and the rich findings from this study underscore the importance of patient registry in studying and reporting DSH incidents on a population level.

The case for case-control studies in the field of suicide prevention

Much of our knowledge about the risk factors for suicide comes from case-control studies that either use a psychological autopsy approach or are nested within large register-based cohort studies. We would argue that case-control studies are appropriate in the context of a rare outcome like suicide, but there are issues with using this design. Some of these issues are common in psychological autopsy studies and relate to the selection of controls (e.g. selection bias caused by the use of controls who have died by other causes, rather than live controls) and the reliance on interviewing informants (e.g. recall bias caused by the loved ones of cases having thought about the events leading up to the suicide in considerable detail). Register-based studies can overcome some of these problems because they draw upon contain information that is routinely collected for administrative purposes and gathered in the same way for cases and controls. However, they face issues that mean that psychological autopsy studies will still sometimes be the study design of choice for investigating risk factors for suicide. Some countries, particularly low and middle income countries, don't have sophisticated population-based registers. Even where they do exist, there will be variable of interest that are not captured by them (e.g. acute stressful life events that may immediately precede a suicide death), or not captured in a comprehensive way (e.g. suicide attempts and mental illness that do not result in hospital admissions). Future studies of risk factors should be designed to progress knowledge in the field and overcome the problems with the existing studies, particularly those using a case-control design. The priority should be pinning down the risk factors that are amenable to modification or mitigation through interventions that can successfully be rolled out at scale.

Rates and characteristics of suicide by immigration background in Norway

Suicide mortality among immigrant groups is an important health issue, particularly in countries with growing segments of immigrant populations such as Norway. Through linkage of Norwegian national registers we wanted to estimate suicide rates (per 100,000 population) in immigrant groups and to profile characteristics of suicide by immigration background with respect to sex, age, method and seasonality of suicide as well as time since immigrating to Norway. Among all 11,409 suicides during 1992-2012, 1,139 (10%) were individuals with an immigration background. Suicide rate was lower in first-generation immigrants (foreign-born persons to two foreign-born parents) than native Norwegians (9.53 vs 12.22, P < 0.01), with a significant difference confined to male rates only. Foreign-born persons with at least one Norwegian-born parent had significantly higher suicide rates than natives in both sexes (22.42 vs 18.03 in males, 11.67 vs 6.54 in females, P < 0.01). The most frequently used suicide method in all the population groups was hanging; this method accounted for 44.0% of all suicides of first-generation immigrants, 45.2% of all suicides of foreign-born persons with at least one Norwegian-born parent, and 35.4% of all suicides of natives. Suicide by firearms accounted for a much smaller proportion of cases of first-generation immigrants (6.7%) and foreign-born persons with at least one Norwegian-born parent (6.8%) than cases of native Norwegians (20.7%). In terms of monthly distribution, suicides of first-generation immigrants displayed two peaks, in May and in November (P = 0.01). More than 25% of all first-generation immigrant suicides occurred in the first five years after immigration; but differences in time since immigration were observed by sex and country group of origin, in particular among those aged 35 years or less when moving to Norway. In conclusion, there are notable differences in characteristics of suicides by immigration background. Knowledge of immigrant mortality according to suicide method, seasonality of suicide, and time since immigration may be useful when planning suicide preventive measures.