Association between homicide rates and suicide rates: a countrywide longitudinal analysis of 5507 Brazilian municipalities

Abstract

ObjectiveTo estimate the association between homicide and suicide rates in Brazilian municipalities over a period of 7 years.DesignWe conducted a longitudinal ecological study using annual mortality data from 5507 Brazilian municipalities between 2008 and 2014. Multivariable negative binomial regression models were used to examine the relationship between homicide and suicide rates. Robustness of results was explored using sensitivity analyses to examine the influence of data quality, population size, age and sex on the relationship between homicide and suicide rates.SettingA nationwide study of municipality-level data.ParticipantsMortality data and corresponding population estimates for municipal populations aged 10 years and older.Primary and secondary outcome measuresAge-standardised suicide rates per 100 000.ResultsMunicipal suicide rates were positively associated with municipal homicide rates; after adjusting for socioeconomic and demographic factors, a doubling of the homicide rate was associated with 22% increase in suicide rate (rate ratio=1.22, 95% CI: 1.13 to 1.33). A dose–response effect was observed with 4% increase in suicide rates at the third quintile, 9% at the fourth quintile and 12% at the highest quintile of homicide rates compared with the lowest quintile. The observed effect estimates were robust to sensitivity analyses.ConclusionsMunicipalities with higher homicide rates have higher suicide rates and the relationship between homicide and suicide rates in Brazil exists independently of many sociodemographic and socioeconomic factors. Our results are in line with the hypothesis that changes in homicide rates lead to changes in suicide rates, although a causal association cannot be established from this study. Suicide and homicide rates have increased in Brazil despite increased community mental health support and incarceration, respectively; therefore, new avenues for intervention are needed. The identification of a positive relationship between homicide and suicide rates suggests that population-based interventions to reduce homicide rates may also reduce suicide rates in Brazil.

Cross-national examination of adolescent suicidal behavior: a pooled and multi-level analysis of 193,484 students from 53 LMIC countries

“…Homicide and suicidal behavior are significantly correlated in Europe [ 7 , 17 , 26 ], but not in the Americas and Asia [ 7 , 17 ] based on global research studies. Within the regional studies, the direction of the associations between suicidal behavior and homicide depended on geographical locations with positive associations mostly observed in Europe and no or a negative association in the Americas [ 7 , 17 ].…”

“…Seven country-level variables were identified for inclusion in the multilevel analysis. These included the Gini coefficient (GC), Gross Domestic Product (GDP) per capita, the pupil-to-teacher ratio in primary schools, the population density, the intentional homicide rate, laws regarding suicide and the night light index [ 11 , 21 , 26 , 30 , 32 , 45 , 48 ]. These variables were selected based on their importance as key socio-economic indicators as well as their potential to influence mental wel-being at population levels [ 4 , 11 , 41 ].…”

Interpersonal violence and depression in Brazil: A cross-sectional analysis of the 2019 National Health Survey

“…Any violence, whether witnessed or directly experienced, has been strongly associated with developing depression and suicidal behaviour, in both high-income countries and LMICs [9]. At the municipality-level in Brazil, higher homicide rates have even been associated with higher suicide rates [10]. There is less research assessing whether those with depression and prior experience of violence have a different likelihood of having their depression diagnosed and treated.…”

One stream, two channels? A parallel-process latent class growth model of homicide rates and suicide rates in 183 countries, between 2000 and 2019

“…Their studies showed that suicide rates were positively related to the business cycle, while homicide rates were negatively related. However, other studies suggested a positive and parallel rate relationship between suicide and homicide ( Holinger & Klemen, 1982 ; Machado et al, 2020 ; McKenna et al, 1997 ). Although these inconsistencies are, in part, explained by different sampling approaches, sample sizes and analytic strategies, there are also suggestions that the rate relationship between suicide and homicide varies across countries, and time periods (e.g., Bills & Li, 2005 ; Fountoulakis & Gonda, 2017 ).…”