Homicide mortality in Mexico is still a priority public-health issue. In 2012, it was one of the most frequent causes of death in men aged 15-44 years. Some Mexican States, including the State of Jalisco, show homicide mortality rates significantly higher than others; 48% of the homicides recorded in the country during the period 1990-2017 were committed in Jalisco. Important local-level differences have also been documented within the State; up to 50% of the homicides reported by official sources are usually perpetrated in the Guadalajara Metropolitan Zone (AMG, for its acronym in Spanish).

The importance of gathering evidence based on spatially referenced data to address this issue is being increasingly recognized, not only to evaluate homicide mortality, but also to identify population groups at risk and high-priority areas, examine epidemiological behavior, and identifying spatial or temporal trends. Public health and healthcare geography provide various analytical tools that can be useful for supporting decision-making to better focus interventions aimed at reducing and preventing homicide mortality. The objectives of this study were to estimate the magnitude and identify the spatial distribution and trends of homicides perpetrated in the years 2013 and 2018 in the AMG, comparing the results at municipal and neighborhood levels.

There are two official sources of homicide statistics in Mexico: the Instituto Nacional de Estadística y Geografía (National Institute of Statistics and Geography; INEGI, for its acronym in Spanish), and the Secretariado Ejecutivo del Sistema Nacional de Seguridad Pública (Executive Secretariat of the National Public Security System; SESNSP). However, both provide data aggregated at State or municipal levels only. To overcome this limitation, INEGI statistics were supplemented with local newspaper reports to derive the following information for homicides in the AMG in 2013 (n = 465) and 2018 (n = 988): date, address, neighborhood, and municipality where each homicide was perpetrated. These data allowed examining the geographic distribution of homicides across the 1,710 neighborhoods in the six AMG municipalities (Guadalajara, Zapopan, San Pedro Tlaquepaque, Tonalá, El Salto, and Tlajomulco de Zúñiga). Geostatistical techniques were used to analyze the distribution and spatial trend of homicide incidence from the point location data. The frequency of homicides by neighborhood and municipality were also calculated to estimate and map homicide rates (number per 100,000 inhabitants) for comparison vs. the aggregated data reported by INEGI for the two years studied.

According to the two official data sources, homicide mortality increased from 2013 to 2018 in most of the AMG, except for the municipality of Zapopan; the increase was particularly high in the municipalities of Tlajomulco de Zúñiga and San Pedro Tlaquepaque, where the homicide rate increased from 20.3 to 50.7 and 4.6 to 18.8 homicides per 100,000 inhabitants, respectively. The geographic analysis of point-location data showed a high concentration of homicides in low-, medium-, and high-marginalization areas of the north and southwest parts of the municipality of Zapopan (29.2% of the homicides reported in 2013), as well as in the center and northeast parts of Guadalajara (14%). By contrast, the zones with high concentration of homicides in 2018 (25.4%) shifted towards the low-marginalization neighborhoods located on the northeast, central, and south parts of Guadalajara, in the limits between the municipalities of Tonalá and San Pedro Tlaquepaque.

The homicides perpetrated in 2013 were distributed in 16.8% of the neighborhoods that make up the AMG, whereas those perpetrated in 2018 took place in 24.4% of the neighborhoods. Mortality rates in 2013 ranged from 4 (at the low-marginalization Miramar neighborhood, Zapopan) to 223.3 (at the low-marginalization Revolucionaria neighborhood, Guadalajara) homicides per 100,000 inhabitants; and from 3.8 (in the very high-marginalization Santa Cruz de Las Flores neighborhood, Tlajomulco de Zúñiga) to 2,006 (in the very high-marginalization Toluquilla neighborhood, San Pedro Tlaquepaque) homicides per 100,000 inhabitants in 2018.

Despite of having used different sources and territorial scales for the geographic analysis, we were able to identify consistent patterns in the increase in homicide mortality from 2013 to 2018 in the AMG. These results provide valuable information for guiding strategies and available resources to target priority areas where the magnitude, distribution, and spatial trends observed at neighborhood and municipality levels indicate a high incidence of homicides and, thus, reduce the risks facing the population (54%) in the AMG neighborhoods recording high homicide rates.