Abstract
Colombia and Mexico are among the countries in the region with the highest rates of homicide mortality and are also the drug traffickers in the world. The objective of this study was to analyze the trends and differences in homicide mortality in Colombia and Mexico between 1990 and 2016. Using data from the Global Burden of Disease Study, we report mortality rates and trends in years of life lost to homicides. This study looked at injuries occurring because of interpersonal violence, which was divided into three types (firearm, sharp object, and others). The homicide mortality rate steadily decreased since 1992 in Colombia, while in Mexico, it varied over time. This rate in Colombia has not been reduced to Mexico’s level, and in turn, Mexico has not had a mortality rate as high as Colombia’s. Throughout the period, in both countries, the years of life lost rate decreased (52% in Colombia and 18.6% in Mexico); however, between 2002 and 2016, the years of life lost rate from homicides was reduced in all age groups in Colombia, and in Mexico, they increased notably, mainly between 15 and 54 years of age. Public health plays a central role in abating interpersonal violence through the prevention of risk factors, and through making information available so that decision-makers can create public policies using evidence-based arguments. The Global Burden of Disease Study is a crucial resource that can be used to define, describe, and evaluate the consequences of homicides and help direct efforts and resources to the most vulnerable groups.
Violence is a complex, multicausal, social condition stemming from the interaction of social, political, economic, historical, and cultural factors (García et al., 2012; Malta et al., 2017; Muggah & Aguirre, 2018; Salama, 2013). It produces direct consequences on the physical and mental health of communities (Moreno & Cendales, 2011). Interpersonal violence (homicides) has been associated with poverty, social inequality, and social, educational, or labor exclusion (Malta et al., 2017); the weakness of the state as reflected in high rates of impunity and corruption and easy access to firearms (Barcellos & Zaluar, 2014); and rapid and unplanned urbanization and accelerated demographic changes (Arif, Jawaid, & Iqbal, 2017; Rivera, 2016).
In 2012, 437,000 total homicides were estimated globally with a rate of 6.2 per 100,000 people (United Nations Office on Drugs and Crime, 2013). Men comprised 79% of the victims, revealing a male mortality rate of 9.9 per 100,000 people, versus 2.7 in females. The highest mortality rate for homicides was found among those aged 15 to 29, followed by the 30 to 49 age group (United Nations Office on Drugs and Crime, 2013). The Global Burden of Disease Study (GBD) estimated that 4.8 million people were killed in 2013 because of violence and accidents, of which 8.5% were victims of homicide (GBD 2016 Causes of Death Collaborators, 2017).
Violence in Latin America has reached “epidemic” levels and has the highest homicide mortality rate of the world’s regions (United Nations Development Programme, 2013). Over one third of the world’s homicides concentrated there ((World Health Organization, 2014). The distribution of mortality rates from homicides in Latin America varies widely. There are countries with relatively low rates of below 10 homicides per 100,000 inhabitants such as Argentina, Peru, Bolivia, Chile, Costa Rica, Cuba, and Uruguay, while other countries such as Mexico, Panama, Ecuador, and Paraguay present rates that fluctuate between 13 and 20 homicides. Several countries have higher rates, like Brazil, Guatemala, Colombia, El Salvador, Honduras, and Venezuela, with 28 or more homicides (GBD 2016 Causes of Death Collaborators, 2017; Naghavi et al., 2018; Weiss, Rennó Santos, Testa, & Kumar, 2016).
In recent years, there has been a growing interest in quantifying and comparing the magnitude and impact of violent deaths in Colombia and Mexico, particularly because both countries have some of the world’s highest levels of drug production and trafficking (Arson, Olson, & Zaino, 2014; Dávila-Cervantes & Pardo-Montaño, 2014, 2018; Paul, Colin, & Chad, 2014). This has unleashed full-scale conflicts between the states and powerful drug trafficking cartels. These conflicts in turn create complex contexts that reflect the specific internal dynamics of each nation, in which the violence associated with drug trafficking coincides with civil conflicts and other common forms of violence such as urban crime (Arson et al., 2014; Dávila-Cervantes & Pardo-Montaño, 2014, 2018; Paul et al., 2014). The contrast between countries is an opportunity to understand how different risk factors may be interacting with similar results (Naghavi et al., 2018).
Colombia was one of the most violent countries in the world in the 1990s and the beginning of the 2000s, with a homicide rate of over 60 per 100,000 inhabitants, but with a sharp decline beginning in 2002 (GBD 2016 Causes of Death Collaborators, 2017; Dávila-Cervantes & Pardo-Montaño, 2014, 2018; Naghavi et al., 2018; Pan American Health Organization, 2017). During the same period beginning in 1990, Mexico had a relatively lower homicide rate with below 13 homicides per 100,000 inhabitants (Dávila-Cervantes & Pardo-Montaño, 2014, 2018). However, since 2008, the mortality rate from homicides in Mexico has increased sharply, peaking in 2011 at 28 per 100,000 inhabitants and placing it among Latin America’s most violent nations (GBD 2016 Causes of Death Collaborators, 2017; Pan American Health Organization, 2017).
Interpersonal violence has been analyzed from many perspectives and varied multidisciplinary approaches. However, only recently have we seen an emphasis on the need to examine not only the magnitude of the problem but also the impact that interpersonal violence has on society’s various spheres. The objective of this study was to analyze the trends and differences in homicide mortality in Colombia and Mexico between 1990 and 2016.
In sociodemographic terms, Colombia and Mexico have some similarities: They are at an advanced stage of their demographic transition and most of the population is concentrated in urban areas. The Colombian population is approximately 45.5 million inhabitants (the third most populous nation in Latin America), of which 77.8% live in urban areas. The average age is 31, and the life expectancy at birth is 74 years. By age groups, 22.5% are below 15 years old, 68.3% are between 15 and 64, and 9.2% are 65 or older (National Administrative Department of Statistics, 2019). In Mexico, by 2016 the population was 122,715,165 (the second most populated nation in Latin America), of which about 78% reside in urban areas. The average age is 28, and the life expectancy at birth is estimated at around 72.2 years. In 2015, 27% of the population was below 15 years old, 65% was between 15 and 64, and 7.2% was 65 or older (National Population Council, 2016).
Method
This study is a secondary analysis based on the GBD (2016) overseen by the Institute for Health Metrics and Evaluation at the University of Washington. The GBD is a systematic scientific effort to quantify and compare the burden of diseases, injuries, and risk factors, disaggregated by 23 age groups, sex, geographic area, and year. In 2016, the study included 195 countries and territories, and subnational evaluations for 12 countries, using data beginning in 1990. The study recognized 333 diseases and injuries, 2,982 sequelae, and 84 risk factors or combinations of risk factors (Institute for Health Metrics and Evaluation, 2016; Murray & López, 2017).
Data sources used to estimate deaths from injury consist of vital registration systems, verbal autopsy, mortality surveillance, censuses, surveys, hospitals, police records, and morgue data. Additional data sources used include the United Nations Office on Drugs and Crime Global Study on Homicide, the United Nations Surveys on Crime Trends and the Operations of Criminal Justice Systems 1970-2006, and the WHO Mortality Database (Naghavi et al., 2018). The International Classification of Diseases (ICD) was used to classify injuries. In the GBD, injury incidence and deaths are defined as ICD-9 codes E000-E999 and ICD-10 chapters V to Y. In particular, for the GBD 2016 study, injury causes were organized into 26 mutually exclusive and collectively exhaustive external cause-of-injury categories. “Self-harm” was distinguished into “self-harm by firearm,” and “self-harm by other specified means” (Naghavi et al., 2018). This study looked at injuries occurring because of interpersonal violence, divided into three types (by instrument): firearm, sharp object, and other (Naghavi et al., 2018).
Several corrections were made to the data derived from mortality indices (for age and sex) and to the incorrect classification of causes of death (Murray & López, 2017). Causes of death were reassigned to ensure their correct classification. The study’s methodological details have been published previously (Murray & López, 2017).
Using the GBD, we obtained standardized rates for each of the three types of injuries described above, as well as the respective rates of years of life lost (YLL) because of premature mortality. The GBD defines the YLL as the amount of time a person would have lived if they had not died prematurely. It is obtained by multiplying the number of deaths in each age group by the average life expectancy of that group, independent of sex. The reference standard life expectancy is 86 years, derived from the lowest observed death rate in the world by age and sex. This represents the age to which people across the globe can hope to live (Lozano et al., 2013; Murray & López, 2017). This study looked at injuries occurring because of interpersonal violence, divided into three types by instrument: firearm, sharp object, and other.
To account for uncertainties that arise from sample sizes of data, adjustments to sources of all-cause mortality, model specifications in spatiotemporal Gaussian process regression, model life table systems, and cause-specific model specifications and estimations, the GBD produced 1,000 draws of all mortality metrics and estimated uncertainty intervals (UI) in key steps of the all-cause mortality and cause-specific mortality rates and death numbers for each location, by sex, for all years (Wang et al., 2016).
Results
Colombia suffered 22,937 deaths from interpersonal violence in 1990, compared with 16,662 in 2016. Homicide by firearm was the most common cause of death, followed by homicides by sharp object and other causes. The mortality rate dropped by 49%, from 67 (95% UI 48.7-75.4) per every 100,000 inhabitants to 34.3 (95% UI 25.5-41.9), with a more dramatic decrease beginning in 2002 (Table 1). The standardized rates for homicides by firearm, by sharp object, and other specified means decreased, by varying magnitudes. The rate of homicide by firearm went from 52.7 (95% UI 33.7-60.2) to 25.9 (95% UI 17.7-32.0), the most marked and significant decrease of the three causes (51%). The rate of homicide by sharp object changed from 10.2 (95% UI 5.9-15.7) to 5.6 (95% UI 3.2-9.4), a drop of 45%, although not statistically significant. The rate of homicide by other specified means fell from 4.2 (95% UI 2.1-6.8) to 2.8 (95% UI 1.6-5.7), a reduction of 32% (Table 1).
Mortality Rate of Homicides by Instrument: Colombia and Mexico, 1990-2016.
Source. Authors’ elaboration based on the Institute for Health Metrics and Evaluation (2016).
Note. UI = uncertainty intervals.
In Mexico, there were 16,248 deaths from interpersonal violence in 1990; that rose to 21,087 by 2016. This is a 12% increase in the absolute number of deaths, but a statistically insignificant decrease in the mortality rate, which moved from 18.8 (95% UI 11.5-22.9) to 16.4 (95% UI 10.4-20.9) per 100,000 inhabitants. In contrast to Colombia (whose violent death rates fall almost continuously since 1992), in Mexico these changes have evolved in different directions. From 1990 to 2004 the rates decreased; this situation reversed from 2005 to 2011 when rates progressively increased, to fall again between 2012 and 2016. The mortality rate registered in 2016 was equal to that of 2009, as well as that of 1995. The principal cause of death from interpersonal violence was homicide by firearm, whose rate in 2016 (10.8; 95% UI 5.4-13.4) was as high as in 1990 (10.7; 95% UI 5.5-14.3). The homicide rate by sharp object decreased by 11%, from 3.5 (95% UI 1.8-5.1) in 1990 to 2.9 (95% UI 1.7-5.3) in 2016. The rate of homicide by other specified means displayed this same pattern, falling from 4.8 (95% UI 2.1-6.3) to 2.7 (95% UI 1.5-4.8), a decrease of 43% (Table 1).
Two differences stand out when comparing the two countries. First, during this entire period and across all the causes of homicide (except by other specified means from 1990 to 1997), Colombia had much higher mortality rates than Mexico. Second, the largest divergence in rates is in homicide by firearm in 2001, for which Colombia presented a mortality rate 7 times higher than Mexico. Although these gaps have been closing, in 2016 Colombia still had higher rates of homicide by firearm and sharp object than Mexico, by factors of 2.4 and 1.9, respectively. For homicide by other specified means, the rate was the same. Throughout these 27 years, Colombian homicide rates by firearm and by sharp object have never lowered to the levels in Mexico, and Mexico has never had rates as high as Colombia for these types of homicides.
In 2016, homicide deaths translated into 872,741 YLL in Colombia. Of these, 76% were homicides by firearm, 16% by sharp object, and 8% by other specified means. In Mexico, the burden of YLL ascended to 1,071,029; 66% due to homicides by firearm and 17% for homicides by sharp object and other specified means. In both countries, YLL rates due to interpersonal violence have declined, although in different proportions (52% in Colombia and 18.6% in Mexico). In Colombia, YLL rates from homicide by firearm fell by over 50% between 1990 and 2016, and have generally decreased throughout the entire period. In Mexico, although these rates also decrease between 1990 and 2002 (34%), the YLL due to homicides by firearm between 2002 and 2016 increased by 44%, with a sharp increase among those aged 15 to 40. For homicides by sharp object, Colombia also saw a reduction in YLL higher than that observed in Mexico (50% and 18%, respectively), although this overall rate was higher in Colombia throughout the entire period. Finally, the rate of YLL due to homicide by other specified means also fell in both countries, but in 1990 Mexico had a higher rate than Colombia, a relationship which was reversed by 2016 (Figure 1).

Rate of YLL of homicides by instrument: Colombia and Mexico, 1990-2016.
In both countries, the highest number of YLL from interpersonal violence occurred among people in working age (15-44 years old). Of all homicides, 81.8% in Colombia and 78.4% in Mexico were concentrated in this age group, the sharpest peak being in young people aged 20 to 25. While firearms were the primary cause of YLL due to homicide in almost all age groups, infants lost more years of life from homicide by other specified means (in Colombia about 1% of deaths of children below 5, and in Mexico 2% of deaths of children below 10) (Figure 2). The changes in the rates of YLL by age group due to interpersonal violence can be divided in two main periods: 1990-2002 and 2002-2016. In Colombia, during the first period, YLL rates decreased in almost all age groups, predominantly in those aged 5 to 14 and 30 to 64. There were, however, small increases among Colombians aged 1 to 4, 15 to 24, and 80 to 94 (Figure 3). During the second period, the country continued along this trajectory for all age groups, but by a more marked decrease, especially among those aged 15 to 49. In contrast, for the 1990-2002 period, Mexico’s YLL rates decreased relatively equally across age groups, while during the following period, 2002-2016, the YLL rate raised in young people and adults (aged 15 to 54) as well as in older adults (aged 65-79).

Percentage distribution of YLL of homicides by age groups and instrument: Colombia and Mexico, 2016.

Percentage of change of the YLL rate for homicides by age groups: Colombia and Mexico, 1990-2002 and 2002-2016.
Discussion
Violence, especially homicides, inflicts a notable burden on the health of populations. It also considerably erodes nations’ economies, largely because those most affected by homicide are young people of productive age (Aguirre & Restrepo, 2010; Dávila-Cervantes & Pardo-Montaño, 2014, 2018; González-Pérez, Vega-López, Cabrera-Pivaral, Vega-López, & Muñoz de la Torre, 2012; Meneses-Reyes & Fondevila, 2012; Moreno & Cendales, 2011). Violence also brings high individual and collective costs (Ingram & Marchesini da Costa, 2017). This study shows the magnitude and the changes in interpersonal violence in Colombia and Mexico in the last 27 years. In both countries, firearms have been the leading cause of death in interpersonal violence. Between 1990 and 2016, mortality rates from this cause decreased in Colombia. In Mexico, however, the decline in homicides by firearms was interrupted around 2005, when the rate began to increase until 2011 when it returned to levels registered 20 years earlier.
This phenomenon has an important meaning, because firearms are more lethal than other weapons and therefore are the most extreme expression of violence (González-Pérez & Vega-López, 2019; González-Pérez et al., 2012; Naghavi et al., 2018). It was recently reported that between 2000 and 2016, the global percentage of homicide by firearm was 32%. The percentage was lower in high-income countries (the United States being the exception) and higher in medium- and low-income countries. In Latin America and the Caribbean, the figure was considerably higher: 78% in Central America, 53% in South America, and 51% in the Caribbean (Muggah & Aguirre, 2018). The percentage of death by firearm in Colombia was 75.5% and in Mexico 65.6% (2016) (GBD 2016 Causes of Death Collaborators, 2017). Nonetheless, it is fundamental to keep in mind that other forms of violence have become more evident as well, which also cause serious repercussions in individuals’ lives. Just like firearm deaths, this violence should also be monitored and addressed. Although these forms of violence are nonlethal, they can inflict physical and mental disability, and cause the loss of productivity and a general deterioration in life quality (Dávila-Cervantes & Pardo-Montaño, 2014, 2018; González-Pérez & Vega-López, 2019; González-Pérez et al., 2012; World Health Organization, 2017).
Trends in mortality rates from interpersonal violence can be contextualized in the ongoing processes in each country. In Colombia, at the beginning of the 1990s, the government initiated an aggressive offensive against the nation’s drug trafficking lords, which did not lead to significant reductions in the homicide rates (Arson et al., 2014; Baron, 2009; Paul et al., 2014). Direct hits against drug lords only precipitated fighting between cartel factions, while the paramilitary groups grew stronger in various parts of the country (Arson et al., 2014; Baron, 2009; Rangel, 2000). Later, in 1999, Plan Colombia was implemented, with a clear intervention by the United States. The Plan focused on the idea that security, and the capacity to control drug trafficking and illegal armed groups, was necessary for economic growth, social equality, reducing poverty, and strengthening social and political institutions (Arson et al., 2014; Baron, 2009; Patterson, 2007). The sharp drop in the homicide rate from 2002 onward is attributed to the increase in the mobility and effectiveness of the armed forces gradually generated by Plan Colombia. This led to increased crime prevention, the gradual dismantling of drug trafficking organizations into smaller groups (Baron, 2009), and a decrease in cocaine cultivation, all of which hindered the financing of armed groups and their operations (Arson et al., 2014; Baron, 2009).
In Mexico, the gradual decline in the interpersonal violence homicide rate that held throughout the 1990s was reversed in the last decade (Dávila-Cervantes & Pardo-Montaño, 2014, 2018; Gómez-Dantés et al., 2016; González-Pérez & Vega-López, 2019), mostly related to military operations in several Mexican states as part of the “war on drugs” (Lee & Bruckner, 2017; Salama, 2013). The initial objective of these military interventions was to dismantle the leadership of the drug cartels and thus crushing the criminal organizations into smaller, more “controllable” groups (Molzahn, Rodriguez-Ferreira, & Shirk, 2013). However, the detention or death of cartel leaders only temporarily interrupted their operations. Breaking up their inner structures set off internal wars of succession within and among criminal organizations contending for power. This caused an even higher wave of homicides, the victims being primarily young adults (Arson et al., 2014; Molzahn et al., 2013; Paul et al., 2014; Salama, 2013).
The situation is worrisome. Despite its improvements, Colombia continues to have one of the region’s highest mortality rates (only lower than El Salvador, Venezuela and Guatemala, according to the GBD 2016) (Institute for Health Metrics and Evaluation, 2016; Naghavi et al., 2018). The most recent official report on mortality in Mexico indicates that the number of homicides registered in 2017, 32,079, is the highest in the past 20 years (National Institute of Statistics and Geography, 2018). As a result, life expectancy in both countries has suffered a downturn, mainly among men. In 2011, the homicide YLL among men in Colombia was at 0.83, and in Mexico it was 0.39 years. In Colombia, the reduction in YLL has varied by age group: younger people aged 15 to 34 have not had as marked a decrease as have older people aged 35 to 49 (Dávila-Cervantes & Pardo-Montaño, 2014, 2018). In Mexico, homicide and diabetes are the principal causes behind the stagnation of life expectancy among men, which has remained at 72 since the year 2000 (Aburto, Beltrán-Sánchez, García-Guerrero, & Cánudas-Romo, 2016; Cánudas-Romo, Aburto, García-Guerrero, & Beltrán-Sánchez, 2017; González-Pérez & Vega-López, 2019).
These findings show different realities grappling with the same problem. Solutions require focalized interventions suited to each geographic context, taking population age groups into account, and incorporating a human rights perspective (Muggah & Aguirre, 2018). The intersectoral participation of many societal elements must form the base of these strategies, encompassing health, education, economics, security, and more (Muggah & Aguirre, 2018; Naghavi et al., 2018; World Health Organization, 2014, 2017). Approaches that involve diverse sectors of society to prevent homicides can build upon this foundation. These efforts must closely complement a general strengthening of the social fabric (family, schools and community) at the deepest level (Muggah & Aguirre, 2018; Naghavi et al., 2018; World Health Organization, 2014, 2017). This, in turn, requires reducing socioeconomic inequality, broadening education and job opportunities, increasing participation in sports and recreation, and addressing risk factors that feed situations that breed violence, such as drug and alcohol consumption (Muggah & Aguirre, 2018; Naghavi et al., 2018; World Health Organization, 2014, 2017). It is also necessary to consolidate those institutions responsible for safeguarding public security, enact gun control policies, and increase security forces’ technical and professional capacities (Arson et al., 2014; Briceño-León, 2012; Rivera, 2016).
Today, we know that violence is avoidable (Naghavi et al., 2018; Rutherford, Zwi, Grove, & Butchart, 2007; United Nations Office on Drugs and Crime, 2013). We also know that public health plays a central role in abating violence in two main ways: first, through the prevention of biological and behavioral risk factors that may lead to violence, and second, through making information available so that decision makers can create public policies using evidence-based arguments (Rutherford et al., 2007; World Health Organization, 2003).
The GBD Study is a crucial resource that can be used to define, describe, and evaluate the consequences of homicides, and help direct efforts and resources to the most vulnerable groups. However, these data must be analyzed within the social, political, economic, and cultural context of each place. Local population studies must also complement these data, which enable us to understand the causes of the violence, the relationships between the murderers and the victims, and the individual and collective consequences. To do this, it is critical—both in Colombia and in Mexico—to strengthen the official mortality registries, as well as those registries proceeding from epidemiological monitoring, and medical and hospital care.
Our study was limited by several factors. First, it is possible that mortality rates due to interpersonal violence are underestimated. When murders occur during armed conflicts or at the hands of illegal groups, they may not be reported and thus not counted in national registries (Moreno & Cendales, 2011); this is a limiting factor in this study. However, the GBD offers an advanced statistical methodology focused on minimizing the complications in estimating mortality rates by cause; this makes the GBD a key source to utilize in the formulation of public policy (Murray & López, 2017). This study also has the advantage of using the GBD, which has not been widely exploited in this region despite its wealth of data covering a broad period. In addition, this study is focused on the impact of homicides, although it is clear that violence is also a societal burden when it is not lethal, for example, by leaving victims handicapped. It is suggested that future studies explore this aspect further.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
