​Is suicide mortality associated with neighbourhood social fragmentation and deprivation? A Dutch register-based case-control study using individualised neighbourhoods

Neighborhood material versus social deprivation in Canada: different patterns of associations with child and adolescent mental health problems

PURPOSE

In a nationwide study, we aimed to study the association of neighborhood deprivation with child and adolescent mental health problems.

METHODS

We used data from the Canadian Health Survey on Children and Youth (N = 47,871; age range: 1-17 years) and linked these to Neighborhood Material and Social Deprivation data calculated using Canada's Census of Population. Using a series of logistic regressions, we studied the association between living in deprived areas and mental health problems among children and youth. We used bootstrap replicate weights for all analyses and adjusted them for individual sociodemographic characteristics.

RESULTS

In the adjusted model, the parent-reported developmental disorder was associated with more socially deprived neighborhoods (OR 1.29; 95% CI 1.07, 1.57 for most vs. least deprived quintiles). However, mental health service need or use was associated with living in less materially deprived areas (OR 0.78; 95% CI 0.63, 0.96 for most vs. least deprived quintiles). Among mental health problems reported by the youth (12-17 years old), poor/fair general mental health, alcohol drinking, and cannabis use were associated with neighborhood social deprivation in the adjusted models. In contrast, poor/fair general mental health, suicide ideas, alcohol drinking, and cannabis use were all negatively associated with higher materially deprived quintiles.

CONCLUSION

Our study provides further support for the existing evidence on the association between neighborhood deprivation, particularly social deprivation, and the mental health of children and adolescents. The findings can help public health policymakers and service providers better understand and address children's mental health needs in their neighborhoods.

The complexities of suicide: a multilevel survival analysis examining individual, familial and neighbourhood determinants of suicide risk using Danish register-based data

BACKGROUND

Suicide risk is complex and nuanced, and how place impacts suicide risk when considered alongside detailed individual risk factors remains uncertain. We aimed to examine suicide risk in Denmark with both individual and neighbourhood level risk factors.

METHODS

We used Danish register-based data to identify individuals born in Denmark from 1972, with full parental information and psychiatric diagnosis history. We fitted a two-level survival model to estimate individual and neighbourhood determinants on suicide risk.

RESULTS

We identified 1723 cases of suicide in Denmark during the follow-up period from 1982 to 2015. Suicide risk was explained mainly by individual determinants. Parental comorbidities, particularly maternal schizophrenia [incidence rate ratio (IRR): 2.29, 95% CI 1.56-3.16] and paternal death (2.29, 95% CI 1.31-3.72) partly explained suicide risk when adjusted for all other determinants. The general contextual effect of suicide risk across neighbourhoods showed a median incidence rate ratio (MRR) of 1.13 (1.01-1.28), which was further reduced with full adjustment. Suicide risk increased in neighbourhoods with a higher proportion of manual workers (IRR: 1.08; 1.03-1.14), and decreased with a higher population density (IRR: 0.89; 0.83-0.96).

CONCLUSION

Suicide risk varies mainly between individuals, with parental comorbidities having the largest effect on suicide risk. Suicide risk was less impacted by neighbourhood, though, albeit to a lesser extent than individual determinants, some characteristics were associated with suicide risk. Suicide prevention policies might consider targeting interventions towards individuals more vulnerable due to particular parental comorbidities, whilst taking into account that some neighbourhood characteristics might exacerbate this risk further.

The association between social fragmentation and deaths attributable to alcohol, drug use, and suicide: Longitudinal evidence from a population-based sample of Canadian adults

BACKGROUND

Social fragmentation has been theorized and empirically associated with suicide in prior research. However, less is known about whether social fragmentation is associated with deaths attributed to alcohol use or drug use. This research examined the association between social fragmentation and risk for deaths attributable to alcohol use, drug use, and suicide (collectively known as deaths of despair) among Canadian adults.

METHODS

A weighted sample representing 15,324,645 Canadians within 288 census divisions between 2006 and 2019 was used. Mortality data from the Canadian Vital Statistics Database (alcoholic liver disease, drug use, and suicide) was linked with census division socioeconomic data from the 2006 Canadian census using the Canadian Census Health and Environment Cohorts. Social fragmentation at the census division was created based on the Congdon Index. Cox-proportional hazard regression with survey weights and the sandwich estimator were used to account for clustering of individuals (level-1) nested within census divisions (level-2).

RESULTS

After adjusting for individual and census division confounders, social fragmentation was positively associated with all-cause mortality (HR = 1.04; 95% CI: 1.02, 1.07), suicide (HR = 1.09; 95%CI: 1.01, 1.18), drug overdose related mortality (HR = 1.13; 95%CI: 1.03, 1.24), and deaths of despair (HR = 1.10; 95% CI: 1.04, 1.16), and not significantly associated with alcohol related liver disease (HR = 1.06; 95% CI: 0.91, 1.23).

CONCLUSION

Social fragmentation is associated with an increased hazard of deaths of despair among Canadian adults. Efforts to improve social cohesion in areas that are highly socially fragmented need to be evaluated.

Longitudinal associations of neighbourhood environmental exposures with mental health problems during adolescence: Findings from the TRAILS study

BACKGROUND

Cross-sectional studies have found associations between neighbourhood environments and adolescent mental health, but the few longitudinal studies mainly focused on single exposure-based analyses and rarely assessed the mental health associations with environmental changes.

OBJECTIVES

We assessed longitudinal within- and between-person associations of multiple neighbourhood time-varying physical and social environmental exposures with externalising and internalising problems throughout adolescence.

METHODS

We used four waves of TRAILS (Tracking Adolescents' Individual Lives Survey) data on self-reported externalising and internalising problems at ages 11, 13, 16, and 19 among 2,135 adolescents in the Netherlands. We measured residence-based time-varying environmental exposures, including green space, air pollution (fine particulate matter (PM2.5)), noise, deprivation, and social fragmentation. We fitted random-effect within-between regression models to assess the environment-mental health associations.

RESULTS

At the within-person level, an interquartile range (IQR) increase in PM2.5 was associated with a 0.056 IQR (95% CI: 0.014, 0.099) increase in externalising problems, while an IQR social fragmentation increase was associated with a 0.010 IQR (95% CI: -0.020, -0.001) decrease in externalising problems. Stratification revealed that the association with PM2.5 was significant only for movers, whereas the association with social fragmentation remained only for non-movers. At the between-person level, an IQR higher noise was associated with a 0.100 IQR (95% CI: 0.031, 0.169) more externalising problems, while higher deprivation (β = 0.080; 95% CI: 0.022, 0.138) and lower fragmentation (β = -0.073; 95% CI: -0.128, -0.018) were associated with more internalising problems. We also observed positive between-person associations between PM2.5, noise, and internalising problems, but both associations were unstable due to the high PM2.5-noise correlation. Further, we observed a non-linear between-person PM2.5-externalising problems association turning positive when PM2.5 > 15 µg/m3. Null associations were found for green space.

CONCLUSION

Our findings suggested that air pollution, noise, and neighbourhood deprivation are risk factors for adolescent mental health. Not only exposure levels but also exposure changes matter for adolescent mental health.

'The area I'm from is very rough': Drug users' views on the role of social and economic factors in their experiences of drug-related harm

Over the last thirty-five years, academic researchers in Ireland have consistently demonstrated the relationship between social deprivation and the most severe instances of drug-related harm. More recently, researchers have begun to include the voices of drug users with lived experiences of harm in these discussions. However, these studies have more often tended to focus on drug users' views on alternative drug policy options, rather than their views on the social and economic factors relevant to their experiences of drug-related harm. Therefore, the current study conducted 12 in-depth interviews with drug users experiencing harm in an Irish city, in order to elicit their views on the specific role they believe social and economic factors played in conditioning their later experiences of drug--related harm. The study participants highlight harms experienced in the education system, the family home, and the local community as more relevant to their later experiences of drug-related harm than their social deficits in education, a lack of resources in the local community or in their families. Many participants also discuss meaningful relationships as the last defence against these harms and argue that the loss of such relationships coincided with their most severe incidences of drug-related harm. The study concludes with a discussion of the conceptual framework of structural violence in terms of its potential for interpreting the participants' views and suggests several avenues for further research.

Objective and subjective neighbourhood characteristics and suicidality: a multilevel analysis

BACKGROUND

Characteristics of the neighbourhood environment, including population density, social fragmentation, and trust, have been linked to mental health outcomes. Using a longitudinal population-based cohort, we explored the relationship between objective and subjective neighbourhood characteristics and the odds of suicidal thoughts and attempts.

METHODS

We conducted a longitudinal study of 20764 participants living in Stockholm County who participated in the Stockholm Public Health Survey. We used multilevel modelling to examine if suicidal thoughts and attempts were associated with neighbourhood characteristics, independent of individual associations. We included objective and subjective measures to explore if there was a different relationship between these measures of the neighbourhood environment and suicidality.

RESULTS

Associations between neighbourhood factors and suicidality were predominantly explained by individual characteristics, with the exception of neighbourhood-level deprivation and average residential trust. Each unit increase of deprivation was linked to increased odds of suicidal thoughts [Odds ratio (OR) 1.04, 95% confidence interval (CI) 1.00-1.07] and attempts (OR 1.11, 95% CI 1.06-1.17). Decreasing residential trust was associated with increased odds of suicide attempts (OR 1.09, 95% CI 1.02-1.17). There was no evidence that neighbourhood-level fragmentation or average trust in public and political institutions had an independent effect on suicidality once individual and sociodemographic factors were accounted for.

CONCLUSIONS

This study showed that much of the neighbourhood-level variation in suicidal thoughts and attempts could be explained by compositional factors, including sociodemographic clustering within neighbourhoods. The independent effect of neighbourhood-level deprivation and average residential trust provide evidence that the neighbourhood context may exert an independent effect on suicidality beyond the impact of individual characteristics.

Economic Development and Gender Ratio Change in Chinese Suicide Rates (1990-2017)

Objective: The overall gender ratio in Chinese suicide rates has substantially changed during the past three decades. In this study, we investigated the social economic factors and the mechanisms that may be contributing to this fluctuation. Study Design: This is a secondary analysis using suicide mortality data from the China Centers for Disease Control and Prevention. Methods: A statistical model was performed with province as the unit of analysis. The per capita GDP and income of each provincial-level region were collected from the Economic and Statistical Yearbook. Rate and ratio were used to describe the trend of variations, and correlation analyses were conducted to examine the association between economic development and gender ratio change. Results: The China overall male to female gender ratio of suicide rates increased as the GDP per capita grew (r = 0.439; p = 0.015). The gender ratio changed from 0.88 in 1990 to 1.56 in 2017, with the reversion point between 1995 and 2000. The most radical reverse changes in the gender ratios were found in large municipalities. Conclusions: Cultural and social economic variables may explain the gender ratio changes. Increased economic development has significantly reduced psychological strains on rural young women, which in turn decreased the suicide rate among this sub-population.

Living near coasts is associated with higher suicide rates among females but not males: A register-based linkage study in the Netherlands

Exposure to blue spaces may promote psychological wellbeing and reduce mental distress. Whether these effects extend to suicide is unknown. We used register data from 14 million Dutch adults aged 18-64-years between 2007 and 2016 in a nested case-control study to estimate associations between blue space exposures and suicide risk. Each suicide case was matched to ten randomly selected controls. Two blue space exposures were assigned over a ten-year residential address history: distance to the closest inland blue space and distance to the coast. We fitted (gender-stratified) conditional logistic regressions to the data. Possible effect modifications by income were also examined. In total, our analyses included 9757 cases and 95,641 controls. Effect estimates for distance to the closest inland blue space in the total population showed that people living farthest away from inland blue space were at-risk. Suicide risk was lower among women who lived farther away from the coast; no significant effect was observed for men. No evidence was observed that income modified these associations. Our findings provide suggestive evidence that living close to the coast is associated with greater suicide risk for women, while living closer to inland blue spaces may add to the resilience against suicide in the total population. Past research shows that coastal proximity protects against milder forms of mental illness, but these protective effects do not appear to hold for suicide. Blue space interventions for women with severe mental illness or propensities to engage in self-harm should be approached with caution.

Neighborhood social context and suicide mortality: A multilevel register-based 5-year follow-up study of 2.7 million individuals

Previous studies have linked neighborhood social characteristics to suicide mortality. However, the effects of the operational definition of neighborhoods and the general importance of neighborhood context on suicide mortality have received little attention, with most studies using various administrative areas as neighborhood delineations. In this study, neighborhoods were delineated by micro-areas generated with an automated redistricting algorithm and divided by physical barriers, such as large roads. The geographic data were linked to register data on the Danish adult population in the age range of 20-59 years in December 2013 (N = 2,672,799 individuals nested into 7943 neighborhoods). This cohort was followed for five years to evaluate the association between suicide mortality and neighborhood socioeconomic deprivation, social fragmentation, and population density. We used the median hazard ratio (MHR) to quantify the general contextual effect (GCE) of neighborhoods on suicide mortality and hazard ratios to quantify the specific contextual effects (SCEs) using multilevel survival models stratified by age group. The results showed a larger GCE and larger SCEs of neighborhoods on suicide mortality for individuals aged 20-39 years compared with those aged 40-59 years. After controlling for individual characteristics, higher suicide mortality was observed for individuals living in the least densely populated neighborhoods and the most socially fragmented neighborhoods for both age groups. We found cross-level interactions between neighborhood population density and gender and ethnicity for those aged 40-59 years, as well as between neighborhood social fragmentation and ethnicity for those aged 20-39 years. The results indicate that beyond individual characteristics, the neighborhood social context may affect the risk of suicide, especially for people aged 20-39 years.

Associations between social fragmentation, socioeconomic deprivation and suicide risk across 1887 municipalities in Japan, 2009-2017: a spatial analysis using the Bayesian hierarchical model

OBJECTIVE

Previous studies have indicated that spatial variation in suicide mortality is associated with area-specific socioeconomic characteristics, such as socioeconomic deprivation and social fragmentation. However, most of these studies have been conducted in the West and findings from Asian countries are limited. This study aims to investigate associations between socioeconomic characteristics and suicide mortality rates across 1887 municipalities in Japan between 2009 and 2017. We also assessed these associations by gender and age group.

METHODS

Suicide data were obtained from the suicide statistics of the Ministry of Health, Labour and Welfare in Japan and included information on the number of suicides by gender, age and municipality location. Social fragmentation, socioeconomic deprivation and urbanicity were used as socioeconomic characteristics in this study and were created from survey data obtained from the 2010 census. Bayesian hierarchical models were used to examine associations between socioeconomic characteristics and suicide risk.

RESULTS

Suicide rates were significantly higher in municipalities with higher levels of deprivation, with a rate ratio of 1.13 (95% credible interval: 1.10 to 1.17) in the highest quartile compared with the lowest. Higher levels of urbanicity had significantly lower suicide rates, with a rate ratio of 0.79 (95% credible interval: 0.77 to 0.82) in the highest quartile compared with the lowest. However, associations between exposures and suicide varied considerably by gender and age. Among both men and women aged 0-39 years, fragmentation was significantly associated with suicide, with rate ratios of 1.07 and 1.15 for men and women, respectively, in the highest quartile compared with the lowest.

CONCLUSION

Suicide prevention in Japan should particularly focus on areas with high levels of deprivation or low levels of urbanicity. Furthermore, young Japanese people residing in the most fragmented municipalities were also at high risk of suicide, and appropriate measures need to be taken.

Inequalities of Suicide Mortality across Urban and Rural Areas: A Literature Review

Suicide mortality is a major contributor to premature death, with geographic variation in suicide rates. Why suicide rates differ across urban and rural areas has not yet been fully established. We conducted a literature review describing the urban–rural disparities in suicide mortality. Articles were searched in five databases (EMBASE, PubMed, PsychINFO, Scopus, and Web of Science) from inception till 26 May 2021. Eligible studies were narratively analyzed in terms of the urban–rural disparities in suicides, different suicide methods, and suicide trends over time. In total, 24 articles were included in our review. Most studies were ecological and cross-sectional evidence tentatively suggests higher suicide rates in rural than in urban areas. Men were more at risk by rurality than women, but suicide is in general more prevalent among men. No obvious urban–rural pattern emerged regarding suicide means or urban–rural changes over time. Potential suicidogenic explanations include social isolation, easier access to lethal means, stigmatization toward people with mental health problems, and reduced supply of mental health services. For research progress, we urge, first, individual-level cohort and case-control studies in different sociocultural settings. Second, both rurality and urbanicity are multifaceted concepts that are inadequately captured by oversimplified typologies and require detailed assessments of the sociophysical residential environment.

Ethnicity and suicide risk: A population-based study from England

Using multiple linked electronic health databases, we conducted a large case-control study in England from 2001 through 2019 to examine the association between ethnicity and suicide risk. Asian, Black and Other ethnic groups had a significantly lower suicide risk compared to White individuals, with those of Asian ethnicity having the lowest risk (Odds Ratio 0.53, 95% Confidence Interval 0.47-0.60). This ethnicity related suicide risk was significantly altered by socio-demographic characteristics. These factors can inform the assessment and stratification of suicide risk, as well as the targeting of public health measures designed to reduce suicide incidence.

Longitudinal effects of physical and social neighbourhood change on suicide mortality: A full population cohort study among movers and non-movers in the Netherlands

Associations between the residential neighbourhood environment and suicide mortality are well-established; however, most evidence is cross-sectional and not capable of incorporating place-based and residential moving-related neighbourhood changes. We studied how suicide mortality is associated with changes in the physical and social neighbourhood environment for movers and non-movers. Our retrospective analysis was based on longitudinal register data for the entire Dutch population aged 25-64 years enriched with annually time-varying data on the residential neighbourhood environment between 2007 and 2016. A total of 8,741,021 people were followed-up between 2007 and 2016 of which 10,019 committed suicide. Upward and downward neighbourhood change was measured by comparing neighbourhood conditions separately at two time points. Cox proportional hazard models indicated that movers had a significantly lower risk of suicide compared to non-movers. Suicide risk was lower for people experiencing improvements in social fragmentation and deprivation compared to those remaining in poor conditions. Change from rural to urban conditions also resulted in lower suicide risk, while a gain in green space put people at increased risk. For those stable neighbourhood conditions over time, suicide mortality was lower for men and women in urban vs. rural neighbourhoods as well as for women in neighbourhoods with low vs. high social fragmentation. Stable exposure to high levels of green space resulted in higher suicide risk among women. Interactions and stratification by moving type revealed associations between neighbourhood change and suicide were more pronounced in non-movers. Our findings suggest that neighbourhood improvements might contribute to a lower suicide risk, especially for long-term residents in poor neighbourhood conditions.

Identification of socio-demographic, occupational, and societal factors for guiding suicide prevention: A cohort study of Swiss male workers (2000-2014)

INTRODUCTION

We modeled suicidal rate among Swiss working-age males, considering three groups of factors at socio-demographic, occupational, and societal levels jointly. Our goal was twofold: to verify the effect of occupation after adjustment for non-occupational factors and to identify protective and risk factors relevant for suicide prevention in working male adults.

METHODS

The study population included all men aged [18-65] years at the 2000 population census and followed up within the Swiss National Cohort (SNC). The risk of suicide was modeled using Poisson regression.

RESULTS

The cohort comprised 1,534,564 men and 4371 deaths by suicide. Suicide rate varied significantly according to age, civil status, nationality, highest education achieved, and socio-professional category at socio-demographic level; occupation, occupational activity branch, weekly working hours, and home-to-work commute time at occupational level; calendar period of death, region, religious affiliation, and volunteering activity at societal level. After adjustment for non-occupational factors, agricultural and fishery laborers, military and civil security workers, and health and social workers were identified as high-risk groups with respect to suicide.

CONCLUSION

This study evidenced a complex web of factors at socio-demographic, occupational, and societal levels behind the suicide in Swiss male workers and identified the most at-risk groups, deserving targeted prevention efforts.

Longitudinal exposure assessments of neighbourhood effects in health research: What can be learned from people's residential histories?

Health research into neighbourhood effects has generally examined neighbourhoods cross-sectionally, ignoring the fact that neighbourhood exposures might accumulate over people's lives and affect health outcomes later in life. Using longitudinal Dutch register data with complete 15-year residential address histories, we examined whether health effects of neighbourhood socioeconomic characteristics differ between cumulative and current exposures. We illustrated these differences between exposure assessments using suicide mortality among middle-aged adults. All suicides aged 40-64 years between 2012 and 2016 were matched with 10 random controls in a nested case-control design. We measured neighbourhood exposures longitudinally for circular buffers around residential addresses at the current address and through three accumulative measures, each incorporating the residential address history with increasing detail. Covariate-adjusted conditional logistic regressions were used to assess associations between suicide and neighbourhood social fragmentation, population density and unemployment rate. Our results showed that total and male suicide mortality was significantly lower in highly fragmented neighbourhoods when using accumulative exposures, but not when using the current residential address. However, we observed few differences in coefficients between exposures assessments for neighbourhood urbanicity and unemployment rate. None of the neighbourhood characteristics showed evidence that detailed cumulative exposures were a stronger predictor of suicide compared to more crude measures. Our findings provide little evidence that socioeconomic neighbourhood characteristics measured cumulatively along people's residential histories are stronger predictors of suicide mortality than cross-sectional exposures.

Geography of suicide in Japan: spatial patterning and rural-urban differences

PURPOSE

There are notable geographic variations in incidence rates of suicide both in Japan and globally. Previous studies have found that rurality/urbanity shapes intra-regional differences in suicide mortality, and suicide risk associated with rurality can vary significantly by gender and age. This study aimed to examine spatial patterning of and rural-urban differences in suicide mortality by gender and age group across 1887 municipalities in Japan between 2009 and 2017.

METHODS

Suicide data were obtained from suicide statistics of the Ministry of Health, Labour and Welfare in Japan. We estimated smoothed standardized mortality ratios for suicide for each of the municipalities and investigated associations with level of rurality/urbanity using Bayesian hierarchical models before and after adjusting for socioeconomic characteristics.

RESULTS

The results of the multivariate analyses showed that, for males aged 0-39 and 40-59 years, rural residents tended to have a higher suicide risk compared to urban ones. For males aged 60+ years, a distinct rural-urban gradient in suicide risk was not observed. For females aged 0-39 years, a significant association between suicide risk and rurality was not observed, while for females aged 40-59 years and females aged 60 years or above, the association was a U-shaped curve.

CONCLUSION

Our results showed that geographical distribution of and rural-urban differences in suicide mortality in Japan differed substantially by gender and age. These findings suggest that it is important to take demographic factors into consideration when municipalities allocate resources for suicide prevention.

Outdoor light at night, air pollution and depressive symptoms: A cross-sectional study in the Netherlands

BACKGROUND

Artificial light at night (ALAN) may be an anthropogenic stressor for mental health disturbing humans' natural day-night cycle. However, the few existing studies used satellite-based measures of radiances for outdoor ALAN exposure assessments, which were possibly confounded by traffic-related air pollutants.

OBJECTIVES

To assess 1) whether living in areas with increased exposure to outdoor ALAN is associated with depressive symptoms; and 2) to assess the potential confounding effects of air pollution.

METHODS

We used cross-sectional data from people (N = 10,482) aged 18-65 years in the Netherlands. Depressive symptoms were assessed with the Patient Health Questionnaire (PHQ-9). Satellite-measured annual ALAN were taken from the Visible Infrared Imaging Radiometer Suite. ALAN exposures were assessed at people's home address within 100 and 600 m buffers. We used generalized (geo)additive models to quantify associations between PHQ-9 scores and quintiles of ALAN adjusting for several potential confounders including PM_2.5 and NO₂.

RESULTS

Unadjusted estimates for the 100 m buffers showed that people in the 2^nd to 5^th ALAN quintile showed significantly higher PHQ-9 scores than those in the lowest ALAN quintile (β_Q2 = 0.503 [95% confidence intervals (CI): 0.207-0.798], β_Q3 = 0.587 [95% CI: 0.291-0.884], β_Q4 = 0.921 [95% CI: 0.623-1.218], β_Q5 = 1.322 [95% CI: 1.023-1.620]). ALAN risk estimates adjusted for individual and area-level confounders (i.e., PM_2.5, urbanicity, noise, land-use diversity, greenness, deprivation, and social fragmentation) were attenuated but remained significant for the 100 m buffer (β_Q2 = 0.420 [95% CI: 0.125-0.715], β_Q3 = 0.383 [95% CI: 0.071-0.696], β_Q4 = 0.513 [95% CI: 0.177-0.850], β_Q5 = 0.541 [95% CI: 0.141-0.941]). When adjusting for NO₂ per 100 m buffers, the air pollutant was associated with PHQ-9 scores, but ALAN did not display an exposure-response relationship. ALAN associations were insignificant for 600 m buffers.

CONCLUSION

Accounting for NO₂ exposure suggested that air pollution rather than outdoor ALAN correlated with depressive symptoms. Future evaluations of health effects from ALAN should consider potential confounding by traffic-related exposures (i.e., NO₂).

Greenery exposure and suicide mortality later in life: A longitudinal register-based case-control study

BACKGROUND

Exposure to residential greenery accumulates over people's lifetimes, and possibly has a protective association with suicide later in life.

OBJECTIVES

To examine the associations between suicide mortality and long-term residential greenery exposure in male and female adults.

METHODS

Our population-based nested case-control study used longitudinally georeferenced Dutch register data. Suicide cases aged 18-64 years between 2007 and 2016 were matched by gender, age, and date of suicide to 10 random controls. We measured long-term greenery exposure along people's 10-year residential address histories through longitudinal normalized difference vegetation indices (NDVI) from Landsat satellite imagery between 1997 and 2016. We assigned accumulated greenery exposures, weighted by people's exposure duration, within 300, 600, and 1,000 m concentric buffers around home addresses. To assess associations between suicide and greenery, we estimated gender-specific conditional logistic regressions without and with adjustment for individual-level and area-level confounders. Stratified models were fitted for areas with a high/low level of urbanicity and movers/non-movers.

RESULTS

Our study population consisted of 9,757 suicide cases and 95,641 controls. In our models adjusted for age, gender, and date of suicide, the odds ratios decreased significantly with higher quartiles of accumulated NDVI scores. NDVI associations were attenuated and did not remain significant after adjustment for socioeconomics, urbanicity, air pollution, social fragmentation, etc. for either males or females. For females, but not males, our model with 300 m buffers for areas with a low level of urbanicity showed a significant suicide risk reduction with increasing levels of NDVI. Individual risk factors (e.g., lack of labor market participation) outweighed the contribution of greenery.

CONCLUSION

We found limited evidence that long-term greenery exposure over people's lifetimes contributes to resilience against suicide mortality. Ensuring exposure to greenery may contribute to suicide prevention for specific population groups, but the effectiveness of such exposure should not be overstated.

Suicide rates and voting choice in the UK's 2016 national Brexit referendum on European Union membership: cross-sectional ecological investigation across England's local authority populations

BACKGROUND

Individual- and area-level risk factors for suicide are relatively well-understood but the role of macro social factors such as alienation, social fragmentation or 'anomie' is relatively underresearched. Voting choice in the 2016 referendum on the UK's membership of the European Union (EU) provides a potential measure of anomie.

AIMS

To examine associations between percentage 'Leave' votes in the EU referendum and suicide rates in 2015-2017, the period just prior to, and following, the referendum.

METHOD

National cross-sectional ecological study of 315 English local authority populations. Associations between voting choice in the EU referendum and age-standardised suicide rates, averaged for the years 2015, 2016 and 2017, were examined.

RESULTS

Overall there was a weak, but statistically significant, positive correlation between the local authority-level percentage 'Leave' vote in 2016 and the suicide rate 2015-2017: Pearson's correlation coefficient, r = 0.17; P = 0.003. This relationship was explained by populations having an older age distribution, being more deprived and lacking ethnic diversity. However, there was divergence (likelihood ratio test for interaction, χ2 = 7.2, P = 0.007) in the observed associations between London and the provincial regions with Greater London having a moderately strong negative association (r = -0.40; P = 0.02) and the rest of England a weak positive association (r = 0.17; P = 0.004).

CONCLUSIONS

Deprivation, older age distribution and a lack of ethnic diversity seems to explain raised suicide risk in Brexit-voting communities. A greater sense of alienation among people feeling 'left behind'/'left out' may have had some influence too, although multilevel modelling of individual- versus area-level data are needed to examine these complex relationships. The incongruent ecological relationship observed for London likely reflect its distinct social, economic and health context.