Does population density moderate suicide risk? An Italian population study over the last 30 years

Spatial and Environmental Correlates of Prevalence of Treatment for Substance Use Disorders, Retention, and SUD Services Utilization in South Sardinia

This study explored the economic, social, and spatial correlates of treatment prevalence, retention, and service utilization for substance use disorder (SUD) in South Sardinia. Data from 1,667 patients with an ICD-10 diagnosis of SUD were extracted from the medical records of individuals assisted by three public addiction services in 2019. We used a spatial autoregressive model, a parametric proportional hazard model, and Poisson regression to examine the associations of spatial factors and residents' socioeconomic status with the prevalence of treatment at the census block level, treatment retention, and SUD service utilization at the individual level. The prevalence was higher among residents of areas closer to competent treatment centers, with the worst building conservation status, a lower percentage of high school and university graduates, and a higher percentage of unemployed, divorced, separated, or widowed residents. Men who were older at the time of their first treatment access; primary users of cocaine, cannabis, and alcohol; had higher education level; and who lived far from competent treatment centers and closer to drug trafficking centers interrupted their treatment earlier. Primary heroin users experienced more SUD treatment encounters. Living in economically and socially disadvantaged areas and near treatment facilities was associated with a higher prevalence, whereas living near drug-dealing centers and far from competent treatment centers was associated with a decrease in treatment retention.

Epidemiological profile, temporal analysis, and future projections of suicide cases in rural cities in the extreme south of Brazil

The present study aimed to verify the time series (2000-2017) of death rates by suicide and its associated factors in 4 municipalities in the extreme south of Brazil. Data were obtained through the analysis of medical reports and police report bulletins at the Instituto Médico Legal, in the city of Rio Grande. The suicide rate in the Rio Grande region varied from 4 to 11 suicides per 100,000 inhabitants and it is estimated that by 2030 this rate could reach 16.5 suicides per 100,000 inhabitants. The rural cities of Santa Vitória do Palmar and Chuí present even higher suicide averages when compared to Rio Grande, the most populous city of the four. The death rate from suicide increased gradually in the period analyzed, with the prevalence rising among the youngest and the elderly population. A more comprehensive understanding of the influences of environmental issues on suicidal decisions constitutes an important action that needs to be taken, both because of regional vulnerabilities and the target population identified. Evidence indicates that knowledge of factors affecting individuals residing in this Brazilian region where increased suicide rates are recorded needs to be recognized as a priority.

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.

Using iterative random forest to find geospatial environmental and Sociodemographic predictors of suicide attempts

Introduction

Despite a recent global decrease in suicide rates, death by suicide has increased in the United States. It is therefore imperative to identify the risk factors associated with suicide attempts to combat this growing epidemic. In this study, we aim to identify potential risk factors of suicide attempt using geospatial features in an Artificial intelligence framework.

Methods

We use iterative Random Forest, an explainable artificial intelligence method, to predict suicide attempts using data from the Million Veteran Program. This cohort incorporated 405,540 patients with 391,409 controls and 14,131 attempts. Our predictive model incorporates multiple climatic features at ZIP-code-level geospatial resolution. We additionally consider demographic features from the American Community Survey as well as the number of firearms and alcohol vendors per 10,000 people to assess the contributions of proximal environment, access to means, and restraint decrease to suicide attempts. In total 1,784 features were included in the predictive model.

Results

Our results show that geographic areas with higher concentrations of married males living with spouses are predictive of lower rates of suicide attempts, whereas geographic areas where males are more likely to live alone and to rent housing are predictive of higher rates of suicide attempts. We also identified climatic features that were associated with suicide attempt risk by age group. Additionally, we observed that firearms and alcohol vendors were associated with increased risk for suicide attempts irrespective of the age group examined, but that their effects were small in comparison to the top features.

Discussion

Taken together, our findings highlight the importance of social determinants and environmental factors in understanding suicide risk among veterans.

The association between nation-level social and economic indices and suicide rates: A pilot study

Ever since the pioneering work of Emile Durkheim, it has been known that regional or national suicide rates can be influenced by a variety of social and economic factors. Recent research has found a robust association between two country-level economic indices-gross national product and unemployment rate-and suicide rates, particularly in men. However, the association between other country-level social indices-such as measures of social integration, inequality, environmental preservation and political freedom-and suicide rates has not been studied at the cross-national level. In the current study, national suicide rates for men and women were examined in relation to seven indices measuring subjective wellbeing, sustainable development, type of political regime, economic and gender inequality, and social capital. It was found that the Happy Planet Index, a composite measure of subjective wellbeing and sustainable development, was negatively associated with suicide rates independent of gender, and even after adjusting for possible confounding factors. Economic inequality was associated with suicide in men, and social capital was associated with suicide in women. Moreover, the strength and direction of the associations observed between socioeconomic indices and suicide varied across income groups. These results highlight the need for a closer evaluation of the link between large-scale ("macro") social factors and individual ("micro") psychological factors, as well as the importance of integrating these factors into suicide prevention programmes at the national level.

Suicide mortality among the elderly population in Italy: A nationwide cohort study on gender differences in sociodemographic risk factors, method of suicide, and associated comorbidity

OBJECTIVES

This study aimed at investigating gender differences in the relationship between sociodemographic factors and suicide mortality, as well as in the method used for suicide and the presence of comorbidities in an older population in Italy.

METHODS/DESIGN

We conducted a historical cohort study based on individual record linkage across the 15th Italian Population Census, the Italian Population Register, and the National Register of Causes of Death. Suicides among people aged 75 years or older from 2012 to 2017 were analyzed. Crude mortality rates were computed, and cause-specific mortality rate ratios were estimated using negative binomial regression models. Chi-square tests were used to evaluate significant gender differences in suicide methods and comorbidities associated with suicide.

RESULTS

The study included 9,686,698 individuals (41% men, 59% women). Compared to living alone, living with children or partners reduced suicide mortality, especially among men. Having high or medium educational levels was associated with lower mortality than low educational levels among men. Foreign citizens had lower mortality among men, but not among women. Living in urban areas was associated with lower suicide rates in men and higher rates in women. Methods of suicide significantly differed by gender: leading methods were hanging, strangulation, and suffocation in men, and falling from height in women. Mental comorbidity was significantly more frequent among women, especially at ages 75-84 years.

CONCLUSIONS

We believe that our findings might help to promote public health strategies taking gender differences in old age into account to improve social support and quality of life of older men and women.

Investigation of the association between lithium levels in drinking water and suicide mortality in Hungary

BACKGROUND

In recent decades, a series of ecological studies from various countries have attempted to reveal whether there is an association between trace amounts of lithium in drinking water and suicide mortality. With some notable exceptions, results have indicated that there is an inverse association between these two variables. Since Hungary had extremely high rates of suicide with a persistent spatial pattern, we consider that our country is ideal to investigate this research question.

METHODS

We carried out our research on Hungarian data at the level of districts (n = 197). The dependent variable was the age- and gender-standardized mortality ratio for suicide (sSMR). Our main explanatory variable was the tap water lithium level (Li) from public drinking water supply systems using their own water source (n = 1 325). Those data, which give full national coverage, were aggregated to the level of districts. Confounding factors were religiosity, alcohol consumption and income. Various regression models were used for statistical calculations.

RESULTS

Findings from our most appropriate regression model - adjusted for relevant confounding variables and able to handle spatial autocorrelation and heteroscedasticity - suggest a significant (p < 0.05) and a trend-like (p < 0.1) negative association between Li and sSMR in the total population and among males, respectively. However, such an association was not found between these two variables among females.

CONCLUSION

In line with the majority of findings from other countries, our results indicate that the intake of lithium with drinking water may have a gender-dependent suicide-protective effect.

Exploring multiple pathways and mediation effects of urban environmental factors for suicide prevention

Public health is threatened by air pollution and high temperature, especially in urban areas and areas impacted by climate change. Well-designed urban forms have co-benefits on promoting human health and mediating atmospheric environment-related threats (e.g., high temperature and air pollution). Previous studies overlooked these mediating effects of urban form on suicide mortality. This study used partial least squares modeling and countywide data in Taiwan to identify the crucial influences and pathways of urban environment, socioeconomic status, and diseases on suicide mortality. The model considered the impact of the characteristics of urban form (i.e., urban development intensity, land mix, and urban sprawl), urban industrial status (i.e., industrial level), urban greening (i.e., green coverage), disease (i.e., important diseases morbidity of human immunodeficiency virus [HIV], cerebrovascular disease [CVD], chronic liver disease and cirrhosis [CLDC], nephritis, nephrotic syndrome and nephrosis [NNSN], malignant tumor [MT]), socioeconomic status (i.e., income level and aging population rate), and the atmospheric environment (i.e., air pollution and high temperature) on suicide mortality. Optimizing land mix and minimizing urban development intensity and urban sprawl have been found to reduce suicide mortality. The mediating effect of urban form on suicide mortality originated from air pollution and high temperature, and mediating air pollution was greater than high temperature. Furthermore, industrial level, important diseases (HIV, CVD, CLDC, NNSN, and MT) morbidity, an aging population rate, air pollution, and high temperature were associated with an increase in suicide mortality, whereas green coverage and income level were associated with a reduction in suicide rates. The findings demonstrate that appropriate urban policy and urban planning may lower suicide mortality, be useful strategies for suicide prevention, and be a foundation for building a healthy city. Moreover, this study provides clarity on the complex relationship of suicide and the urban environment while identifying crucial factors.

Investigating relationship between particulate matter air concentrations and suicides using geographic information system

Exposure to particulate matter is an important risk factor for mental health disturbances and overall mortality. However, the knowledge on relationship between long-term particulate matter level and suicide rate is limited and requires in-depth study. Population and air pollution data were obtained from the Polish Central Statistics Office and Chief Inspectorate of Environmental Protection for the period 2014-2015. Aspatial multivariate and one factor regression analysis were performed and followed by spatial global regression analysis for district reference units in geographic information system (GIS). At the district level of aggregation, data showed spatial stationarity. The best-fitting spatial global model was based on number of disorders caused by the use of psychoactive substances, number of people treated in psychiatric hospitals, population density, unemployment rate and per capita income. Global spatial model with PM2.5 level parameter was an improvement over the one without it (adj. R2 = 0.87 compared to adj. R2 = 0.83). There is a positive relationship between particular matter concentrations and suicides in Poland. Application of Geographic Information Science analytical functions in medicine can be viewed as a new efficient methodological approach.

Suicidal risks in rural versus urban populations in Sardinia

OBJECTIVE

Rural locations have been associated with suicidal risk; low population density may be a relevant factor. Accordingly, we investigated hypothesized associations between suicidal ideation and behavior with selected geographic and population-related measures and other factors.

METHODS

Consenting adult patients at a mood disorder center in Cagliari, Sardinia, were assessed for the presence of suicidal ideation and acts and their association with selected demographic and clinical factors as well as indicators of urbanicity and rurality, including distance from the region's main metropolitan area, population density, altitude, and population growth trends.

RESULTS

Of 5,668 subjects, 27% had an indication of lifetime suicidal behavior or ideation; 8.6% had at least one suicidal act. Low population density, higher altitude and their interaction, distance from the metropolitan center of the main city (Cagliari), and population decline were associated with greater risk of suicidal ideation or behavior. In addition, and as expected, alcohol or substance abuse, diagnosis of mood disorders, higher depression ratings at intake, being younger at illness-onset, family history of suicide or other psychiatric disorder, being female, unmarried, separated or divorced, currently smoking cigarettes, being unemployed, and having experienced sexual abuse all were more likely in subjects with suicidal ideation or behavior.

CONCLUSION

Suicidal ideation and behavior were associated with indicators of social isolation as well as with previously reported clinical and demographic risk factors.

Changes in the association between the traditional Japanese diet score and suicide rates over 26 years: A global comparative study

BACKGROUND

This study examined the global association between the Traditional Japanese Diet Score and suicide rate.

METHODS

Average food supply and energy supply by country were obtained from the Food and Agriculture Organization of the United Nations Statistics Division database (FAOSTAT). Traditional Japanese Diet Score (TJDS) was calculated from food group classifications. Age-standardized suicide rates per 100,000 people by country were obtained from the Global Burden of Disease 2017 database. The 26-year associations between TJDS and suicide rates were examined controlling for covariates using a mixed-effects model in 138 countries with populations of 1 million or greater.

RESULTS

A significant negative association was found in the analysis of the relationship between TJDS and the prevalence of suicide [β (se) = -0.126 (0.031), p < 0.001]. The interaction term between TJDS and year was also significant [β (se) = -0.011 (0.003), p < 0.001]. The change in the effect of TJDS on suicide rates by year was examined. The effect of TJDS was not significant from 1991 to 1999 but became significant after 2000; the slope of the TJDS to suicide rate in 2017 was -0.270 (95% confidence interval -0.382, -0.169, p < 0.001).

LIMITATIONS

This was a national ecological study and did not consider individual differences in sex, age, and lifestyle.

CONCLUSIONS

TJDS may be is a protective factor for depression, which may prevent suicide. The association between TJDS and suicide rates became stronger over time and was inversely associated with suicide rates after 2000.

Urbanization level and neighborhood deprivation, not COVID-19 case numbers by residence area, are associated with severe psychological distress and new-onset suicidal ideation during the COVID-19 pandemic

BACKGROUND

Recent studies indicate an urgent need to take action against mental health issues during the COVID-19 pandemic. However, the association between larger-scale environmental factors such as living conditions and mental health problems during the pandemic is currently unknown.

METHODS

A nationwide, cross-sectional internet survey was conducted in Japan between August and September 2020 to examine the association between urbanization level and neighborhood deprivation as living conditions and COVID-19 case numbers by prefecture. Prevalence ratios (PRs) for severe psychological distress, suicidal ideation, and new-onset suicidal ideation during the pandemic were adjusted for potential confounders.

RESULTS

Among 24,819 responses analyzed, the prevalence of mental health problems was 9.2% for severe psychological distress and 3.6% for new-onset suicidal ideation. PRs for severe psychological distress were significantly associated with higher urbanization level (highest PR = 1.30, 95% CI = 1.08-1.56). PRs for new-onset suicidal ideation were significantly associated with higher urbanization level (highest PR = 1.83, 95% CI = 1.37-2.45) and greater neighborhood deprivation (highest PR = 1.35, 95% CI = 1.06-1.72). Severe psychological distress and new-onset suicidal ideation were significantly more prevalent when there was higher urbanization plus lower neighborhood deprivation (PR = 1.34 [1.15-1.56], and 1.57 [1.22-2.03], respectively).

CONCLUSION

These findings suggest that it is not the number of COVID-19 cases by residence area but higher urbanization level and greater neighborhood deprivation (lower neighborhood-level socioeconomic status) that are associated with severe psychological distress and new-onset suicidal ideation during the pandemic. These findings differ in part from evidence obtained before the pandemic.