Mohsen Naghavi and Heather Orpana
According to the World Health Organization (WHO), approximately 800,000 people globally die by suicide each year. The WHO’s Comprehensive Mental Health Action Plan includes a target for countries to reduce their suicide mortality rates by 10% by 2020.  Similarly, reducing suicide mortality by a third is one of the Sustainable Development Goal indicators for target 3.4, to reduce premature mortality from non-communicable diseases through prevention and treatment and promote mental health and wellbeing.  Not only are accurate and comprehensive suicide mortality data essential for monitoring progress towards achieving these goals, but they are also necessary to inform the prevention efforts that will move us towards these reductions.
While most high income countries have high quality vital registration systems from which suicide mortality rates can be calculated, few low and middle income countries have high quality vital registration systems. Yet, an estimated 80% of global suicides take place in low and middle income countries.  Even in countries with high quality vital registration systems, suicide deaths may be misclassified due to the difficulty in determining intent, as well as sociocultural, religious, or legal sanctions against suicide. 
In light of increasing international attention on the prevention of suicide, we decided that it was an opportune time to use the data from the Global Burden of Disease Study to provide baseline and historical estimates of suicide mortality across time and geography, and by sex and age group. 
The Global Burden of Disease Study enhances existing data on suicide through data processing that enhances international comparability and partially addresses misclassification by reassignment of ICD codes from ill-defined or improbable cause of death.  In the absence of suicide mortality data for a jurisdiction, the GBD Study estimation process borrows strength across geography and time to calculate estimates of suicide mortality.
Suicide prevention research and strategies must be informed by patterns of suicide mortality. For example, differences in the female to male suicide mortality ratio by socio-demographic index (SDI) are striking, with lower SDI countries generally demonstrating higher female to male mortality ratios. This finding calls for further research to understand what is driving relatively higher suicide rates among women in lower SDI countries, or relatively lower suicide rates among men, as compared to those living in higher SDI countries. Higher rates of suicide death can be due to higher rates of suicide attempt, or choices of methods with higher fatality rates, and this can impact the choice of suicide prevention strategies
We also found that changes in suicide mortality rates over time have not been consistent across age, sex, region, and nation, and important differences in suicide mortality persist between sociodemographic groups. The decrease in the age-standardized mortality rate over time was greater among women (49%) than men (23.8%), and this trend will only further widen disparities in suicide mortality by sex. 
While both the Comprehensive Mental Health Action Plan suicide reduction goal, and the Sustainable Development Goal Indicator on suicide mortality rates both target population levels, it will also be important to monitor whether any reductions are consistent across sociodemographic groups.
One promising observation is the estimated 30% reduction in the global age-standardized suicide mortality reported in our paper; however, despite this progress, if current trends continue, no countries are expected to meet the SDG goal of a one-third reduction in suicide mortality by 2030, based on projected mean values. [5,7]
If we want to ensure meaningful reductions in suicide mortality both globally and at regional and national levels, a continued focus on accurate and comprehensive data on suicide mortality is required, both to inform suicide prevention interventions, and to evaluate their impact on a population level. While the methods of the Global Burden of Disease Study include advances that yield more robust and comprehensive estimates of global suicide mortality, there is still significant room to improve global suicide mortality data, in low-, middle- and high-income countries. Our study provides insight into where efforts might be focused, both for reducing suicide mortality and for collecting better data for a clearer understanding of which populations are most vulnerable.
Heather Orpana is a research scientist at the Public Health Agency of Canada and an adjunct professor with the School of Public Health and Epidemiology at the University of Ottawa. She is also a collaborator with the Global Burden of Disease Study.
Mohsen Naghavi is a Professor of Health Metrics Sciences at the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.
Competing interests: None declared.
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