Educational Levels and Risk of Suicide in Japan: The Japan Public Health Center Study (JPHC) Cohort I

Factors Related to Suicidal Ideation by Gender and Age Group in Korean Adults

BACKGROUND

According to the results of the age-standardized suicide rate (suicide deaths per 100,000 population) published by Organization for Economic Cooperation and Development countries from 2003 to 2019, the suicide rate in Korea is ranked first almost every year, so it should be managed at the national level. To reduce the suicide rate, many scholars are studying suicide. The suicidal process begins with suicidal ideation, progresses through suicide attempts, and ends with suicide. Among them, the frequency of suicidal thoughts was found to be highly correlated with suicide plans and attempts, and it is said that 60% of those who change from suicidal ideation to attempts appear within one year. Therefore, research related to suicidal ideation to lower the suicide rate will contribute to preventing suicide at an early stage.

METHODS

This study used data from the Korea National Health and Nutrition Examination Survey (KNHANES). Among them, data from 2013, 2015, 2017, and 2019 surveyed adults were compared for suicidal ideation among 18,339 adults. Considering the characteristics of the KNHANES data, complex sample analysis was performed considering the primary extraction unit (region), stratification variables, and weights. The Rao-Scott χ² test was stratified by age group to confirm the distribution of suicidal ideation according to general characteristics. Univariate and multiple logistic regression analyses were performed to understand the effect on suicidal ideation.

RESULTS

Among all subjects, the rate of suicidal ideation was 4.75%, and among the age groups, the rate of suicidal thoughts was the highest among those over 80 years old (10.39%). Compared to those who were 50s, those in their 30s had the lowest suicidal ideation (odds ratio [OR], 0.52; 95% confidence interval [CI], 0.39-0.70), and those in their 80s had the highest rate of suicidal ideation (OR, 1.97; 95% CI, 1.38-2.82). Except for those in their 20s, the rate of suicidal ideation tends to increase with age. Overall, the lower 25% of the Euro Quality of Life-5 Dimensions (EQ-5D) index, depression lasting more than two weeks, and subjects with poor subjective health or high stress were more likely to have suicidal ideation. In particular, EQ-5D Index (OR, 5.86; 95% CI, 3.73-9.20), depressive symptoms (OR, 19.65; 95% CI, 9.94-38.83) in 20s, and stress in 80s (OR, 10.87; 95% CI, 5.63-20.96) was the highest, and those had the good subjective health perception in 30s (OR, 0.10; 95% CI, 0.05-0.20) was lowest. Participants in their 30s, 40s, and 60s who were divorced or widowed and those in their 50s and 60s who had never married or lived together were more likely to consider suicide ideation. Except for those in their 20s and 80s, the rate of suicidal ideation tends to increase with lower household income levels.

CONCLUSIONS

In the results of this study, it can be seen that a combination of factors such as a person's personality traits, stress or coping ability to various events, social support, and mental or physical limitations influence suicidal behavior. Suicidal ideation is not simply affected by a single factor but may be influenced by multiple factors.

Midlife suicide: A systematic review and meta-analysis of socioeconomic, psychiatric and physical health risk factors

Suicide is an increasing contributing cause of mortality in middle-aged adults; however, knowledge to guide prevention is limited. This first systematic review and meta-analysis of studies on midlife suicide has provided an overview of published research on this issue and synthesized the evidence on socioeconomic and physical and mental health factors associated with this mortality. Using PRISMA guidelines MEDLINE, Embase, PsycINFO, Scopus and Web of Science were searched for English-language publications that involved persons aged 35 to 65, used individual-level data, and reported prevalence of exposure(s) or relative risks. The search identified 62 studies on midlife suicides and associated factors (28 for SES, 22 for psychiatric disorder and 23 for physical illness). All studies were from high income countries, and most (80.6%) used data from population registries. Meta-analyses showed that the pooled prevalence of exposure in suicide decedents was 57.8% for psychiatric disorder, 56.3% for low income, 43.2% for unemployment, and 27.3% for physical illness. The associated pooled risk ratio was 11.68 (95% confidence intervals: 5.82-23.47) for psychiatric illness of any type, 12.59 (8.29-19.12) for mood disorders, 3.91 (2.72-5.59) for unemployment, 3.18 (2.72-3.72) for being separated or divorced, 2.64 (2.26-3.10) for cancer, 2.50 (0.96-6.38) for central nervous system illness, and 2.26 (1.16-4.41) for low income. In conclusion, midlife suicide is strongly associated with socioeconomic difficulties and physical and psychiatric illnesses that are common in this age population. Future investigations should consider the interactions between risk factors, the intersectionality of sex and ethnicity, and include data from low- and middle-income countries.

Spatial statistical analysis of regional disparities in suicide among policy units in Japan: Using the Bayesian hierarchical model

Suicide prevention is a crucial policy issue in Japan to be addressed nationally. Nevertheless, if there are regional differences in suicide, even in adjacent sub-regions, measures may need to be taken at the sub-regional level. Previous studies have not compared regional differences in suicide based on the size of policy units, such as prefectures, secondary medical areas, and municipalities. This study used the number of suicides from open data for 10 years from 2009 to 2018 to obtain shrinkage estimates of the standardized mortality ratio (SMR) using the Bayesian hierarchical model. We visualized and compared the regional disparities in suicide for each policy unit. For each gender and policy unit, adjacent regions had similar clusters of SMRs and positive spatial autocorrelation of global Moran's I (p < 0.001 for each). Comparisons between each policy unit showed that even if the SMR was low for the prefectural units, there were regions with high SMRs in municipalities and secondary medical areas, and vice versa. It was found that assessing suicide solely on a prefecture-by-prefecture basis may overlook regional disparities in suicide. This research emphasizes the need to establish suicide indicators at the secondary medical or municipal level and execute individual suicide prevention interventions in neighboring communities. Prefectures can also play a role in developing collaborative cooperation between neighboring regions by acting as actors.

Suicidal ideation and suicide attempts among older recipients of public welfare assistance in Japan

BACKGROUND

The high suicide rate among older adults is an important public health issue. Financial insecurity has been linked to suicidal behaviour. Despite this, as yet, there has been little research on suicide-related behaviours among older recipients of public welfare. This study will examine if suicidal ideation and suicide attempts are more prevalent in older recipients of public welfare assistance in Japan.

METHODS

This cross-sectional study analysed data from 16 135 adults aged ≥65 years who participated in the 2019 wave of the Japan Gerontological Evaluation Study. Information was obtained on receiving public welfare assistance, lifetime suicidal ideation and attempts, and a variety of covariates. Poisson regression analysis with robust variance estimates was used to examine associations.

RESULTS

Suicidal ideation was reported by 4.8% of the participants, while the corresponding figure for attempted suicide was 2.2%. In fully adjusted analyses public welfare recipients had an almost 1.5 times higher prevalence of lifetime suicidal ideation (prevalence ratio, PR 1.47, 95% CI 1.02 to 2.13), and an almost two times higher prevalence of attempted suicide (PR 1.91, 95% CI 1.20 to 3.04) when compared with their counterparts not receiving public welfare assistance.

CONCLUSION

Older recipients of public welfare have a higher prevalence of suicidal behaviour in Japan. An urgent focus is now warranted on this vulnerable population to determine the specific factors underlying this association.

Suicides in Turkey: 25-year trend (1995-2019)

The assessment of national suicide risks is considered critical in many countries for the establishment of suicide prevention initiatives aimed at considerably lowering suicide rates. The aim of this study is to identify at-risk suicide populations by reviewing the suicides in Turkey over a 25-year period. The Turkish Statistical Institute's suicide statistics for 1995-2019 in Turkey was retrospectively reviewed in current article. The data collected in the study was statistically analyzed using the MINITAB vn 14 software. Between 1995 and 2019, the total number of suicides in Turkey was 66,819, and suicide rates, especially in males, showed an increasing trend in this period. Males comprised 68.3% of the total cases, and most (27.2%) were aged 15-24 years. Suicides mostly occurred between May and July (27.7%), of individuals with a primary school level of education (51.7%) and who were married (6.0 per 100,000). Illness was most important risk factor for suicide (36.8%) and hanging (47.5%) was the leading suicide method in all age groups and in both genders. Despite the fact that Turkey's suicide rate is lower than many other countries, the growth in male suicide rates is concerning. Suicides are likely to become a severe problem in Turkey in the near future unless measures like education, psychiatric evaluations, the reactivation of psychological counseling service phone lines, and the establishment of youth counseling centers, as described in this paper, are taken.

The causal effect of education and cognitive performance on risk for suicide attempt: A combined instrumental variable and co-relative approach in a Swedish national cohort

BACKGROUND

The aim of this study was to clarify the possible causal associations between education phenotypes and non-fatal suicide attempts. In particular, we evaluated the roles of academic achievement (school grades), cognitive performance (IQ), and educational attainment (education level).

METHODS

Based on longitudinal Swedish registry data, we included 2,335,763 individuals (48.7% female) with available school grades, 1,448,438 men with IQ measures, and 4,352,989 individuals (48.4% female) with available data on education level. We combined two different approaches to aid in causal inference: 1) instrumental variables analysis, using month of birth as an instrument related to education but not suicide attempt, to control for measured and unmeasured confounders, and 2) co-relative analysis, comparing pairs of different genetic relatedness (cousins, half, and full siblings) to control for genetic and environmental influences.

RESULTS

High education was associated with reduced risk of suicide attempt. Instrumental variable analysis indicated evidence of a likely causal association between higher school grades and lower risk of suicide attempts (HR = 0.71). Co-relative analyses supported the causality between the three predictors and suicide attempt risk (school grades, HR = 0.80, IQ, HR = 0.83, education level, HR = 0.76). Finally, we examined the specificity of education phenotypes and found that both cognitive (IQ) and non-cognitive (school grades, education level) processes were involved in suicide attempt risk.

LIMITATIONS

IQ was only available in men, limiting the generalizability of this analysis in women.

CONCLUSIONS

Efforts to support causal associations in psychiatric research are needed to offer better intervention. Programs improving education during adolescence would decrease suicide attempt risk.

Lifetime risk of suicide among survivors of the atomic bombings of Japan

AIMS

The long-term physical health effects of the atomic bombings of Hiroshima and Nagasaki are well characterised, but the psychological effects remain unclear. Therefore, we sought to determine whether measures of exposure severity, as indirect measures of psychological trauma arising from exposure to the atomic bombings, are associated with suicide mortality among atomic bomb survivors.

METHODS

The Life Span Study is a prospective cohort study of 93 741 Japanese atomic bomb survivors who were located within 10 km of the hypocentre in Hiroshima or Nagasaki at the time of the bombings in 1945, and 26 579 residents of Hiroshima and Nagasaki who were not in either city at the time of the bombings, matched to survivors on city, sex and age. Measures of exposure severity included: proximity to the hypocentre, type of shielding between the survivor and the blast and self-reported occurrence of acute radiation and thermal injuries. Date of death was obtained from the Japanese National Family Registry system. Cause of death was obtained from death certificates. Adjusted hazard ratios (HRs) were estimated from Cox regression models overall and stratified by sex and age.

RESULTS

During the 60-year follow-up period (1950-2009), 1150 suicide deaths were recorded among 120 231 participants (23.6 per 100 000 person-years): 510 among 70 092 women (17.2 per 100 000 person-years) and 640 among 50 139 men (33.6 per 100 000 person-years). Overall, there was no association of proximity, type of shielding or the occurrence of acute injuries with suicide mortality. Among those <25 years of age at the time of the bombings, increased suicide risk was observed for survivors outside v. shielded inside any structure (HR: 1.24; 95% confidence interval (CI): 1.03, 1.48; interaction p = 0.054) and for those who reported flash burns (HR: 1.32; 95% CI: 1.00, 1.73; interaction p = 0.025). Sex-stratified analyses indicated that these associations were limited to men. Among women, closer proximity to the hypocentre was associated with a non-significant increase in suicide risk, with a positive association between proximity and suicide risk observed among women <15 years of age (HR: 1.09 per km; 95% CI: 1.00, 1.18; interaction p = 0.067).

CONCLUSIONS

Proximity to the hypocentre, shielding and acute injury presence do not generally appear to influence suicide mortality among atomic bomb survivors. However, heterogeneity may exist by age and sex, with younger survivors potentially more sensitive to psychological trauma. Coupled with other studies, our results suggest the importance of long-term monitoring of mental health among young populations exposed to catastrophic events or mass trauma.

The Mediating Role of Coping Style: Associations Between Intimate Partner Violence and Suicide Risks Among Chinese Wives of Men Who Have Sex With Men

The wives of men who have sex with men, known as "Tongqi" in China, have increasingly attracted public attention due to their potential risks of suicide and sexually transmitted infections and HIV. However, few studies have explored the association between intimate partner violence (IPV) and suicide risk or the mediating effect of coping style on these associations among Tongqi in China. To describe these relationships, a cross-sectional online survey was conducted in China from February 2016 to February 2017. A questionnaire, which consisted of the Revised Conflict Tactics Scales, the Simplified Coping Style Questionnaire, the Beck Scale for Suicidal Ideation, and reports of suicide attempts, was completed by 178 Chinese Tongqi. Bootstrap tests were performed to determine the mediating role of coping styles on the association between IPV and suicide risks. The median IPV score was 14 (range: 0-50), with the domain of negotiation ranking highest. The average coping style score was .37±.73; 61.2% of Tongqi have had suicidal ideation, and 11.8% had attempted suicide. IPV was significantly correlated with suicidal ideation (r^s = .19, p < .01) and suicide attempts (r^s = .29, p < .001). Participants with a negative coping style had higher suicidal ideation (r^s = -.39, p < .01) and suicide attempts (r^s = -.22, p < .01). Coping style had a full mediating effect on the association between IPV and suicidal ideation and a partial mediating effect on suicide attempts. Chinese Tongqi experienced high level of IPV and suicide risks. IPV contributed to the suicide risks of Chinese Tongqi, but these associations were mediated by coping style. Therefore, interventions to improve mental health and prevent suicide risks of Chinese Tongqi should focus on helping them develop a positive coping style to achieve the goal of Healthy China in 2030.

Social policies and change in education-related disparities in mortality in Japan, 2000-2010

Persistent socioeconomic disparity in mortality is a widely observed phenomenon despite improvements in the economic standard of living and the prevailing universal healthcare coverage policy. In this study, we selected Japan as a case in which public universal coverage has maintained horizontal equity in healthcare access while demographic and economic challenges have affected the life chances of vulnerable subpopulations over the past decade. We assessed the changing trends in the education-related disparity in mortality over a decade across demographic subpopulations for different causes of death, with the goal of generating social policy lessons to contribute to closing the mortality gap. Using a deterministic data merge between nationwide census and death records, we estimated age- and sex-specific mortality rates for 14 causes and their education-related gradients with absolute and relative indices of inequality in 2000 and 2010 via Poisson regression. Estimation parameters were standardized to the age structure of the sub-population of high school graduates in 2000 as the reference. The results demonstrated that the relative gaps in all-cause mortality persisted despite a decrease in the average mortality rate over the study period. The absolute gaps in mortality increased for preventable causes of death associated with lifestyle behavior choices. The average mortality worsened among socioeconomically vulnerable populations such as youth and women, who were left behind in the existing social/economic policy. External causes of death such as suicide and traffic accidents showed decreasing absolute gaps in a subpopulation targeted by universal social and labor policy measures. These change patterns indicate that, compared with a high-risk approach, a universal policy approach to dealing with societal and fundamental causes of health inequality seems more effective in reducing the education-related mortality gap in both absolute and relative terms.

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Socioeconomic gaps in mortality persist despite extended healthcare coverage.

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Education-related mortality gaps were confirmed in 2000 and 2010 in Japan.

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Relative inequality in preventable diseases increased under checkup-for-all policy.

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Youth and women, left behind in the current social policy, faced worsened gaps.

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Mortality gaps decreased when a universal policy on societal causes was adopted.

Can We Develop a Risk Map for Suicide Rates? An Ecological Study in Portugal

Place of residence can influence suicide acts, beyond individual characteristics. The aim of this study was to identify areas with a greater risk of suicide, identify possible associations with ecological risk factors and develop a risk map of suicide in Portugal. Spatial scan statistic was used to identify critical areas and associations were analyzed through logistic regression models. The results indicate that the spatial distribution of suicides could be determined by a set of ecological risk factors, and that being a foreigner (OR 26.64; 95% CI 13.15-53.97), having no religion (OR 8.65; 95% CI 4.62-16.19) and having lower levels of education (OR 1.20; 95% CI 1.09-3.64) are associated with a higher risk of suicide in Portugal. Results indicate that local risk factors should be taken into account, in accordance to the priority Health Program in the Mental Health area of the Directorate-General for Health of Portugal.

Use of a Machine Learning Algorithm to Predict Individuals with Suicide Ideation in the General Population

OBJECTIVE

In this study, we aimed to develop a model predicting individuals with suicide ideation within a general population using a machine learning algorithm.

METHODS

Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 11,628 individuals via random down-sampling. This included 5,814 suicide ideators and the same number of non-suicide ideators. We randomly assigned the subjects to a training set (n=10,466) and a test set (n=1,162). In the training set, a random forest model was trained with 15 features selected with recursive feature elimination via 10-fold cross validation. Subsequently, the fitted model was used to predict suicide ideators in the test set and among the total of 35,116 subjects. All analyses were conducted in R.

RESULTS

The prediction model achieved a good performance [area under receiver operating characteristic curve (AUC)=0.85] in the test set and predicted suicide ideators among the total samples with an accuracy of 0.821, sensitivity of 0.836, and specificity of 0.807.

CONCLUSION

This study shows the possibility that a machine learning approach can enable screening for suicide risk in the general population. Further work is warranted to increase the accuracy of prediction.

Factors associated with deaths from suicide in a French nationwide HIV-infected cohort

OBJECTIVES

People living with HIV (PLHIV) are at a higher risk of dying by suicide than the general population. Epidemiological data regarding determinants of suicide in PLHIV are scarce. The aim of this study was thus to study demographic, socio-economic, psychiatric history and immunovirological characteristics associated with death from suicide in the French multicenter Dat'AIDS cohort, from January 2000 to July 2013.

METHODS

This was a nested case-control study. All deceased PLHIV during the study period who died by suicide and whose medical files could be checked were included as cases. Controls were selected using incidence density sampling. For each case, up to four controls were selected among all actively followed PLHIV at the index date (date of death of cases). Controls were matched for time from HIV diagnosis (5-year periods) and clinical centre.

RESULTS

Seventy cases and 279 controls were included in the study. By multivariable analysis, the factors significantly associated with death from suicide were: not having children, active or substituted drug consumption, alcohol intake > 20 g/day or history of alcohol abuse, history of depressive disorder and/or of attempted suicide, and psychotropic drug intake. Conversely, age, gender, country of birth, positive HCV serology and HIV-related factors, such as AIDS status, use of combination antiretroviral therapy (cART), nadir and current CD4 counts and HIV viral load, were not significantly associated with the risk of death from suicide.

CONCLUSIONS

In the cART era, HIV-related factors are not associated with a higher risk of suicide mortality. Suicide prevention measures should target PLHIV with the psychological morbidities observed in our cohort.

Interaction effect of job insecurity and role ambiguity on psychological distress in Japanese employees: a cross-sectional study

Purpose

We examined the interaction effect of job insecurity (JI) and role ambiguity (RA) on psychological distress in Japanese employees.

Methods

Overall, 2184 male and 805 female employees from two factories of a manufacturing company in Japan completed a self-administered questionnaire comprising the scales measuring JI (Job Content Questionnaire), RA (National Institute for Occupational Safety and Health Generic Job Stress Questionnaire), psychological distress (K6 scale), and potential confounders (i.e., age, education, family size, occupational class, and work shift). Taking psychological distress as a dependent variable, hierarchical multiple regression analyses were conducted by gender and employment status (i.e., permanent and non-permanent employees). An interaction term of JI × RA was included in the model.

Results

After adjusting for potential confounders, the main effects of JI and RA on psychological distress were significant regardless of gender or employment status. Furthermore, the significant interaction effect of JI × RA on psychological distress was observed among permanent male employees (β = 0.053, p = 0.010). Post hoc simple slope analyses showed that the simple slope of JI was greater at higher levels of RA (i.e., one standard deviation [SD] above the mean) (β = 0.300, p < 0.001) compared to lower levels of RA (i.e., one SD below the mean) (β = 0.212, p < 0.001). On the other hand, the interaction effect of JI × RA was not significant among permanent or non-permanent female employees.

Conclusions

The present study suggests that higher levels of RA strengthen the association of JI with psychological distress, at least among Japanese permanent male employees.

Ongoing university studies and the risk of suicide: a register-based nationwide cohort study of 5 million young and middle-aged individuals in Sweden, 1993-2011

OBJECTIVES

To investigate the risk of suicide, unnatural death and all-cause death in university students compared with non-students, taking previous educational attainment into account.

DESIGN

Open cohort study of all residents aged 18-39 and living in Sweden at any time between 1 January 1993 and 31 December 2011.

SETTING

We linked data from national registers and calculated person-years during university studies for three time periods (1993-1999, 2000-2005 and 2006-2011). Time as non-student was calculated and categorised according to attained educational level. Incidence rate ratios (IRR) with 95% CIs were calculated with Poisson regression models, controlling for age and period.

PARTICIPANTS

The cohort consisted of 5 039 419 individuals, 51% men and 49% women.

MAIN OUTCOME MEASURES

Incidence of suicide (International Classification of Diseases (ICD)-9: E950-E959, ICD-10: X60-X84) or death with undetermined intent (ICD-9: E980-E989, ICD-10: Y10-Y34), unnatural death (ICD-9: E800-E999 and ICD-10: V01-Y99) and all-cause death.

RESULTS

A total of 7316 deaths due to suicide were identified, of which 541 were registered among university students. The risk of suicide was twofold during ongoing university studies compared with when having attained university education, IRR 2.37 (95% CI 2.07 to 2.72) in men and IRR 2.15 (95% CI 1.77 to 2.61) in women.

CONCLUSIONS

Having ongoing university studies was associated with a higher risk of suicide compared with having attained university-level education. This finding highlights the importance of achieving a deeper understanding of suicidal behaviour during years at university. Further studies should assess risk factors for suicide and suicidal behaviour in university students.