ABSTRACT

Objetive:

To provide a comprehensive analysis of mortality trends from acute pesticide poisoning in Mexico from 2000 through 2021.

Methods:

The governmental records of deaths from acute pesticide poisoning were used. The age-standardized years of life lost and aged-standardized mortality rates were estimated. Significant changes in trends of annual percentage change were identified using Joinpoint regression.

Results:

Between 2000 and 2021, mortality was primarily observed in individuals aged 15 to 19 years. Males were the most affected. Self-inflicted pesticide poisoning was the primary registered reason for death. The age-standardized mortality rate from acute pesticide poisoning was reduced from 2012 to 2021 (APC: -4.4; p=0.003).

Conclusion:

This report is the first study about the mortality rate from acute pesticide poisoning in Mexico. The results provided evidence to consider in developing laws to prevent acute pesticide poisoning.

Keywords
Trend; Mexico; Pesticides; Mortality rate; Poisoning

RESUMO

Objetivo:

Fornecer uma análise abrangente das tendências de mortalidade por envenenamento agudo por pesticidas no México de 2000 a 2021.

Métodos:

Foram usados os registros governamentais de mortes por envenenamento agudo por pesticidas. Foram estimados os anos de vida perdidos estandardizados por idade e as taxas de mortalidade estandardizados por idade. Modificações significativas nas tendências de variação percentual anual foram identificadas usando a regressão Joinpoint.

Resultados:

Entre 2000 e 2021, a mortalidade foi observada principalmente em indivíduos na faixa etária de 15 a 19 anos. Os homens foram os mais afetados. O envenenamento por pesticida autoinfligido foi o principal motivo de morte registrado. A taxa de mortalidade estandardizada por idade por intoxicação aguda por pesticidas foi reduzida de 2012 a 2021 (Annual Percent Change — APC: -4,4; p=0,003).

Conclusão:

Este relatório é o primeiro estudo sobre a taxa de mortalidade por intoxicação aguda por pesticidas no México. Os resultados forneceram evidências a serem consideradas no desenvolvimento de leis para prevenir o envenenamento agudo por pesticidas.

Palavras-chave:
Tendências; México; Pesticidas; Taxa de mortalidade; Envenenamento por pesticidas

INTRODUCTION

Occupational, para-occupational, and environmental exposure to pesticides has been associated with developing several human diseases and disrupting environmental health¹1. Rajmohan KS, Chandrasekaran R, Varjani S. A review on occurrence of pesticides in environment and current technologies for their remediation and management. Indian J Microbiol 2020; 60(2): 125-38. https://doi.org/10.1007/s12088-019-00841-x
https://doi.org/10.1007/s12088-019-00841... ,²2. Tang FHM, Lenzen M, McBratney A, Maggi F. Risk of pesticide pollution at the global scale. Nat Geosci 2021; 14(4): 206-10. https://doi.org/10.1038/s41561-021-00712-5
https://doi.org/10.1038/s41561-021-00712... . The growing need for generating and ensuring the production of agricultural products attributed to population growth is associated with increased pesticide use³3. Hedlund J, Longo SB, York R. Agriculture, pesticide use, and economic development: a global examination (1990–2014). Rural Sociol 2020; 85(2): 519-44. https://doi.org/10.1111/ruso.12303
https://doi.org/10.1111/ruso.12303... . Furthermore, pesticides are employed to control vector-borne diseases (for example, Dengue, Zika, Chikungunya, and others), and the alarming insect resistance to pesticides is related to using new pesticide formulations characterized by high acute toxicity⁴4. Le Goff G, Giraudo M. Effects of pesticides on the environment and insecticide resistance. In: Picimbon JF, ed. Olfactory concepts of insect control - alternative to insecticides: Berlin: Springer International Publishing; 2019. p. 51-78. https://doi.org/10.1007/978-3-030-05060-3_3
https://doi.org/10.1007/978-3-030-05060-... .

Exposure to high doses of pesticides at short times results in an abrupt loss of homeostasis, leading to several physiopathological alterations. In the early 1970s, the World Health Organization (WHO) estimated 500 thousand cases of acute pesticide poisoning per year (WHO Expert Committee on Insecticides and Organization 1973) (this estimate only included accidental poisoning); in the 1980s, acute exposure to pesticides was recognized as a priority problem of public health by the WHO⁵5. Maroni M, Järvisalo J, la Ferla F. The WHO-UNDP epidemiological study on the health effects of exposure to organophosphorus pesticides. Toxicol Lett 1986; 33(1-3): 115-23. https://doi.org/10.1016/0378-4274(86)90076-7
https://doi.org/10.1016/0378-4274(86)900... . At the same time, most countries do not know the number of deaths from acute pesticide poisoning⁶6. World Health Organization. Preventing suicide: a resource for pesticide registrars and regulators [Internet]. Geneva: WHO; 2019 [cited on Feb 25, 2023]. Available at: https://www.who.int/publications-detail-redirect/9789241516389
https://www.who.int/publications-detail-... .

A recent global study about the risk of pesticide pollution indicates that Mexico has a medium to high risk of pesticide pollution. This fact is related to the higher use rate of pesticides. Pesticide use is approximately 2-fold higher in Mexico than the world average⁷7. Schreinemachers P, Tipraqsa P. Agricultural pesticides and land use intensification in high, middle and low income countries. Food Policy 2012; 37(6): 616-26. https://doi.org/10.1016/j.foodpol.2012.06.003
https://doi.org/10.1016/j.foodpol.2012.0... . According to the Food and Agriculture Organization Corporate Statistical Database (FAOSTAT), in the last decade (from 2010 to 2020), an average of 0.5 tons of pesticides were used per thousand hectares of land used for agricultural production in Mexico⁸8. Food and Agriculture Organization of the United Nations. FAOSTAT [Internet]. 2022 [cited on Feb 25, 2023]. Available at: https://www.fao.org/faostat/en/#home
https://www.fao.org/faostat/en/#home... . Agricultural production is associated with acute pesticide poisoning in Mexico; this public health problem was projected to increase with the advent of a technological package that includes new pesticide formulations under the North American Free Trade Agreement (NAFTA)⁹9. Abler DG, Pick D. NAFTA, agriculture, and the environment in Mexico. Am J Agric Econ 1993; 75(3): 794-8. https://doi.org/10.2307/1243594
https://doi.org/10.2307/1243594... . This projection has been verified; the number of cases of acute pesticide poisoning is 4-fold higher after the application of NAFTA than in previous periods. According to a Mexican governmental report, the cases of acute pesticide poisoning have increased over time from 2000 to 2019. The national average of acute pesticide poisoning was 3,500 persons per year¹⁰10. Centro de Estudios para el Desarrollo Rural Sustentable y la Soberanía Alimentaria. Impacto del uso de plaguicidas en el sector agropecuario [Internet]. 2022 [cited on Mar 3, 2022]. Available at: http://201.147.98.23/Ver/Documento/4695
http://201.147.98.23/Ver/Documento/4695... . However, reports about mortality attributed to acute pesticide poisoning are unavailable. For this reason, this study aimed to perform an epidemiological description using the open data of the registered deaths by pesticide intoxication from the Information System of Health of Mexico. The data analyzed was from 2000 through 2021.

METHODS

A retrospective descriptive study was carried out using the epidemiological database from “Secretaría de Salud” (Mexico’s Health Secretary); the records for 2000 through 2021 of deaths associated with acute pesticide poisoning in Mexico were considered. The registered cases included all patients with a recent history of pesticide exposure; pesticide exposure could be confirmed by anamnesis, physical examination, and laboratory test, according to “Sistema estadístico epidemiológico de las defunciones” (Epidemiological, statistical system of deaths)¹¹11. México. Secretaria de Salud. Dirección General de Epidemiología. Sistema de Vigilancia Epidemiológica Convencional. Manual de procedimiento estandarizados para la vigilancia epidemiológica convencional [Internet]. 2021 [cited on Apr 3, 2022]. Available at: https://epidemiologia.salud.gob.mx/gobmx/salud/documentos/manuales/32_ManualSuive.pdf
https://epidemiologia.salud.gob.mx/gobmx... ,¹²12. México. Secretaría de Gobernación. NORMA Oficial Mexicana NOM-017-SSA2-2012, Para la vigilancia epidemiológica [Internet]. 2013 [cited on Apr 03, 2022]. Available at: https://dof.gob.mx/nota_detalle.php?codigo=5288225&fecha=19/02/2013#gsc.tab=0
https://dof.gob.mx/nota_detalle.php?codi... .

The International Classification of Diseases and Related Health Problems, 10^th Revision (ICD-10)¹³13. Food and Agruculture Organization of Unites Nations. World Health Organization. Pesticide residues in food 2016 [Internet]. In: Joint Meeting of the FAO Panel of Experts on Pesticide Residues in Food and the Environment and the WHO Core Assessment Group on Pesticide Residues Rome, Italy, 13–22 September 2016 [cited on Apr 03, 2022]. Available at: https://www.fao.org/3/i6585e/i6585e.pdf
https://www.fao.org/3/i6585e/i6585e.pdf... was used to identify cases. Code T60 indicates death associated with the toxic effects of pesticides. Therefore, the manner of death describes how a death occurs. The considered categories are accidental poisoning by pesticides (Code X48), intentional self-poisoning by exposure to pesticides (Code X68), assault by pesticides (Code X87), and pesticide poisoning of undetermined intent (Code Y18). Additionally, data extracted were restricted by age (five-year age groups), sex, federative state that registered the death, and the year of death registration were considered. The population was extracted from the National Institute of Geography and Statistics INEGI¹⁴14. Estadísticas de defunciones registradas 2021 [Internet]. 2022 [cited on Oct 27, 2022]. Available at https://www.inegi.org.mx/contenidos/saladeprensa/boletines/2022/dr/dr2021_07.pdf
https://www.inegi.org.mx/contenidos/sala... and National Population Council (CONAPO)¹⁵15. Governo de México. Consejo Nacional de Población. Defunciones [Internet]. [cited on May 5, 2021]. Available at: http://indicadores.conapo.gob.mx/Proyecciones.html
http://indicadores.conapo.gob.mx/Proyecc... .

Statistical analysis

We calculated the annual mortality rate per 100 thousand inhabitants (Annual mortality rate: No. of deaths from acute pesticide poisoningNo. of persons in the population​ at midyearX 100,00)¹⁶16. Gordis L. Epidemiologia. Rio de Janeiro: Thieme Revinter Publicações; 2017.. Moreover, the age-standardized mortality rate per 100 thousand inhabitants (∑idiwiyi; d_i: No. of deaths; W_i: Standard worl population according to WHO; Y_i: person – years ar risk),¹⁷17. Bray F, Ferlay J. Age-standardization. Cancer Incid Five Cont. 2021; 11(166): 127-30. and the age-standardized years of life lost rate per 100 thousand inhabitants ASRY(c,s,t)=∑aYLLrate(c,s,a,t)×W(a);YLLrate: years of life lost rate due to pesticide poisoning; c: pesticide poisoning; s: sex; a: age; t: period)¹⁸18. Martinez R, Soliz P, Caixeta R, Ordunez P. Reflection on modern methods: years of life lost due to premature mortality-a versatile and comprehensive measure for monitoring non-communicable disease mortality. Int J Epidemiol 2019; 48(4): 1367-76. https://doi.org/10.1093/ije/dyy254
https://doi.org/10.1093/ije/dyy254... were estimated.

Trends in the mortality parameters were assessed using Joinpoint regression (National Cancer Institute 2022). Joinpoint regression identifies the breakpoints (joinpoints) in which the linear trends are modified in direction or magnitude¹⁹19. Kim HJ, Fay MP, Feuer EJ, Midthune DN. Permutation tests for joinpoint regression with applications to cancer rates. Stat Med 2000; 19(3): 335-51. https://doi.org/10.1002/(sici)1097-0258(20000215)19:3<335::aid-sim336>3.0.co;2-z
https://doi.org/10.1002/(sici)1097-0258(... . This method is performed using a log-linear model following a Poisson distribution log(yi) = ℰ[yi|xi] +εi. The years from 2000 to 2021 are considered X_i; the Y_i represents the annual rates; the εi. Represents residuals for the íth period, and the ℰ[yi|xi] indicates the mean from regression. The mean is estimated considering a successive linear segment (n+1) over the period (from 2000 “a” to 2021 “b” ): [a, b]: ε[yi|xi]=β0+β1xi+δ1(xi−τ1)++⋯+δn(xi−τn)+. The annual percentage change (APC) describes the change in the constant percentage of the prior year’s rate. Moreover, this method indicates whether the modification on the trend line slope could be considered statistically significantly different from zero; we considered four maximum joinpoints and the 4,500 Monte Carlo permutations test. The joinpoint analysis was performed using the “Joinpoint Regression Program version 4.9.1.0”²⁰20. Clegg LX, Hankey BF, Tiwari R, Feuer EJ, Edwards BK. Estimating average annual per cent change in trend analysis. Stat Med 2009; 28(29): 3670-82. https://doi.org/10.1002/sim.3733
https://doi.org/10.1002/sim.3733... .

RESULTS

The mortality rates from acute pesticide poisoning per 100 thousand inhabitants in Mexico from 2000 to 2021 are presented in Figure 1. A total of 7,984 cases of deaths were attributed to acute pesticide poisoning. The highest mortality rate from total cases was observed in 2011, and the lowest rate was observed in 2021. Females’ mortality rates show that the lowest mortality rate was observed in 2021 and the highest in 2001. Males’ mortality rates showed the highest mortality rate in 2011. The mortality rate values for males were highest compared to females (Figure 1). A mortality rate (per 100 thousand inhabitants) from acute pesticide poisoning of 0.32 (confidence intervals — CIs 95% 0.27–0.39) was estimated for Mexico (from 2000 to 2021).

Joinpoint analyses for trends in the age-standardized mortality rate of registered deaths from pesticide poisoning in Mexico from 2000 to 2021 indicate significant variations in trends of annual percentage change (Table 1). From 2000 to 2012, an insignificant increase in the age-standardized mortality rate from acute pesticide poisoning was observed (Annual Percent Change — APC: 0.5; p=0.4). In contrast, a substantial reduction in the age-standardized mortality rate from acute pesticide poisoning was observed in the period from 2012 to 2021 (APC: -4.4; p=0.003). Similar results were observed for estimated trends by sex.

The analysis concerning the national average versus federal states showed that Chiapas and Guerrero states had the highest mortality rate from acute pesticide poisoning compared to the national average. In contrast, the lowest mortality rate was observed for Baja California and Nuevo Leon states (Figure 2).

Intentionally self-poisoning by pesticide exposure was responsible for 55% of deaths. Moreover, thirty-two percent of deaths occurred by accidental poisoning (Supplementary Figure 1a). Men represented 65.2% of deaths from acute pesticide poisoning. The distribution of reasons for deaths from poisonings with pesticide by sex was as follows: intentionally self-inflicted poisoning >accidental poisoning>poisoning of undetermined origin>assault with pesticide (Supplementary Figure 1b). In Supplementary Table 1, the distribution of reasons for deaths from poisonings with pesticide are presented.

Considering the age group, the reasons for death from poisonings with pesticide is shown in Supplementary Figure 2. The age groups severely affected were 15 to 19 and 20 to 24 years. No intentionally self-inflicted poisoning was observed in age groups <9 years.

A total of 330.4 age-standardized years of life lost (ASRY) rate per 100 thousand inhabitants were due to pesticide poisoning in Mexico (from 2000 to 2021). The ASRY associated with acute pesticide poisoning decreases steadily over age. Two peaks were observed in the 15 to 19 and 35 to 39 years. Eighty percent of ASRY linked to acute pesticide poisoning were observed between ten to 49 years (Figure 3). The trend of ASRY showed a significant reduction (APC: -4.71; p<0.001) from 2012–2021 (Table 2).

DISCUSSION

Acute pesticide poisoning is recognized as a public health problem in the world. The use and abuse of pesticides have harsh consequences on human and environmental health. Exposure to the highest dosages of pesticides in a short time results in the abrupt loss of homeostasis, resulting in multiple pathophysiological alterations that could be causes of mortality. The present study analyzed the trends in mortality associated with acute pesticide poisoning in Mexico from 2000 to 2021. The results indicate that intentionally self-inflicted poisoning is the most common death from pesticide poisoning in Mexico.

Guerrero and Chiapas states showed the highest mortality rates from acute pesticide poisoning compared with the national average in the analyzed period (from 2000 to 2021). The agricultural practices in these states are characterized by production on a small scale. All family members generally work on their farming land, and the generated product is intended for auto-consumption or exchanging other products. Therefore, a lower percentage (32%) of producers operate in competitiveness, and generally, agricultural production is performed employing ancestral techniques that result in direct contact with pesticides²¹21. Villafuerte-Solís D. Crisis rural, pobreza y hambre en Chiapas. LiminaR 2015; 13(1): 13-28.

22. Rodríguez-Hernández R, Morales-Guerra M, Sánchez-Vásquez V, Cadena-Iñiguez P, Rendón-Medel R. Vinculación al mercado y competitividad de unidades campesinas en situación de pobreza en Oaxaca, Guerrero y Chiapas. Rev Mex Cienc Agríc 2016; 7(spe15): 3115-28.

23. Laínez-Loyo E, Olvera-Hernández JI, Guerrero-Rodríguez JD, Aceves-Ruiz E, Álvarez-Calderón N, Andrade-Navia JM. Producción y comercialización del mamey en Alpoyeca, Guerrero: opinión de productores. Rev Mex Cienc Agríc 2020; 11(3): 635-47. https://doi.org/10.29312/remexca.v11i3.2086
https://doi.org/10.29312/remexca.v11i3.2... -²⁴24. Guerrero LAT, Juárez GKS. La pequeña producción agrícola y los mercados. Cambios recientes en regiones de Oaxaca. Región y Sociedad 2021; 33: e1500. https://doi.org/10.22198/rys2021/33/1500
https://doi.org/10.22198/rys2021/33/1500... . Furthermore, the lowest levels of the human development index and healthcare access and quality index are associated with Guerrero and Chiapas states. Only Guerrero State has had the shortest life expectancies in Mexico²⁵25. Block MAG, Morales HR, Hurtado LC, Balandrán A, Méndez E. Health systems in transition mexico. Toronto: University of Toronto Press; 2021.. This context could be associated with the highest mortality rate from pesticide poisonings observed in these states.

The increase in the number of attributed deaths to pesticide poisoning was observed in the present study. The same results have been observed in Costa Rica, Nicaragua²⁶26. Wesseling C, Corriols M, Bravo V. Acute pesticide poisoning and pesticide registration in Central America. Toxicol Appl Pharmacol 2005; 207(2 Suppl): 697-705. https://doi.org/10.1016/j.taap.2005.03.033
https://doi.org/10.1016/j.taap.2005.03.0... , and Brazil²⁷27. Luz RAAC, Oliveira ABS, Garcia VC, Rafael LM, Santos JR, Lins LCRF. Epidemiological profile of pesticide poisoning cases in the State of Sergipe, Brazil: a retrospective analysis from 2007 to 2021. Res Soc Dev 2023; 12(4): e14312441127. https://doi.org/10.33448/rsd-v12i4.41127
https://doi.org/10.33448/rsd-v12i4.41127... . The use of highly hazardous pesticides is a commonly identified risk factor for acute pesticide poisoning²⁸28. Boedeker W, Watts M, Clausing P, Marquez E. The global distribution of acute unintentional pesticide poisoning: estimations based on a systematic review. BMC Public Health 2020; 20(1): 1875. https://doi.org/10.1186/s12889-020-09939-0
https://doi.org/10.1186/s12889-020-09939... . For example, exposure to highly hazardous pesticides increased 2.77-fold the risk of death in Brazilians diagnosed with acute pesticide poisoning compared to exposure to pesticides with low /moderate/or high toxicity²⁹29. Okuyama JHH, Galvão TF, Silva MT, Grupo Datatox*. Poisoning and associated factors to death from pesticides: case-control study, Brazil, 2017. Rev Bras Epidemiol 2020; 23: e200024. https://doi.org/10.1590/1980-549720200024
https://doi.org/10.1590/1980-54972020002... . In this line, 46% of ingredient actives of pesticides registered and used in Mexico are considered highly hazardous pesticides according to Food and Drug Administration — FAO-WHO criteria³⁰30. González FB, Márquez DA, Solís JDÁ, Meraz EA, Aguilar OA, Bastidas PJB, et al. Los plaguicidas altamente peligrosos en México [Internet]. 2017 [cited on Apr 03, 2022]. Available at: https://www.rapam.org/wp-content/uploads/2017/09/Libro-Plaguicidas-Final-14-agst-2017sin-portada.pdf
https://www.rapam.org/wp-content/uploads... . Unfortunately, the records of death by acute pesticide poisoning in Mexico do not register the pesticide involved in the incident. Other variables, such as the rural or urban residence and the group chemical of the involved pesticides, are not available data. The lack of these data could be a real impediment to generating laws related to the regulation of the use of pesticides. More variables related to records are necessary for assessing the real impact of the use of pesticides on public health.

The public Mexican health system includes two sublevels of attention. The first level provides health care to formal workers from government and private organizations. Furthermore, the second level provides health care to the rest of the population without affiliation at the first level³¹31. Dantés OG, Sesma S, Becerril VM, Knaul FM, Arreola H, Frenk J. The health system of Mexico. Salud Publica Mex 2011; 53 Suppl 2: s220-32. PMID: 21877087. In 2011, the Mexican government consolidated the Health Information System (Sistema de informacion en salud — SIS:). The SIS increases the accuracy of records in national health statistics. This event could explain the peak in the registered mortality rate from 2011³²32. Mexico. Secretaria de Salud. Programa nacional de salud 2007-2012. Por un México sano: construyendo alianzas para una mejor salud [Internet]. 2007 [cite don Nov 4, 2023]. Available at: https://www1.paho.org/hq/dmdocuments/2010/politicas_nacionales_salud-mexico_2007-2012.pdf
https://www1.paho.org/hq/dmdocuments/201... . Another peak in the registered mortality rate was observed in 2015. In the same year, the importation of methamidophos, a highly hazardous pesticide, showed the maximum peak in the importation (1,620 tons) from 2010 to 2019³³33. Instituto Nacional de Ecología y Cambio Climático, Martínez Arroyo A, Ruiz Suárez LG, Gavilán García A, Mendoza Cantú A. Perspectivas de las importaciones y las exportaciones de plaguicidas en México. Mexico: Instituto Nacional de Ecología y Cambio Climático; 2020.. Methamidophos is widely used in Mexico³⁴34. Ramirez-Vargas MA, Huerta-Beristain G, Guzman-Guzman IP, Alarcon-Romero LDC, Flores-Alfaro E, Rojas-Garcia AE, et al. Methamidophos induces cytotoxicity and oxidative stress in human peripheral blood mononuclear cells. Environ Toxicol 2017; 32(1): 147-55. https://doi.org/10.1002/tox.22220
https://doi.org/10.1002/tox.22220... ,³⁵35. Sánchez-Alarcón J, Milić M, Bonassi S, Gómez-Arroyo S, Cortés-Eslava J, Flores-Márquez AR, et al. Occupational exposure to pesticides: DNA damage in horticulturist from Nativitas, Tlaxcala in Mexico. Environ Toxicol Pharmacol 2023; 100: 104141. https://doi.org/10.1016/j.etap.2023.104141
https://doi.org/10.1016/j.etap.2023.1041... . The increase in the accessibility to highly hazardous pesticides could be related to the mortality rate observed in 2015. Nevertheless, the information about death from acute pesticide poisoning can be considered the result of interaction between multifactorial factors resulting in complex repercussions.

According to WHO and FAO, self-inflicted pesticide poisoning is one of the most common methods of suicide in several countries. The use of highly hazardous pesticides is a similar risk factor observed in these countries⁶6. World Health Organization. Preventing suicide: a resource for pesticide registrars and regulators [Internet]. Geneva: WHO; 2019 [cited on Feb 25, 2023]. Available at: https://www.who.int/publications-detail-redirect/9789241516389
https://www.who.int/publications-detail-... . Intentionally self-inflicted poisoning was the most frequent event in deaths from pesticide poisoning in Mexico (from 2000 to 2021). Similar results have been reported in Brazil³⁶36. Neves PDM, Mendonça MR, Bellini M, Pôssas IB. Poisoning by agricultural pesticides in the state of Goiás, Brazil, 2005-2015: analysis of records in official information systems. Cien Saude Colet 2020; 25(7): 2743-54. https://doi.org/10.1590/1413-81232020257.09562018
https://doi.org/10.1590/1413-81232020257... , India³⁷37. Prashar A, Ramesh M. Assessment of pattern and outcomes of pesticides poisoning in a tertiary care hospital. Trop Med Int Health 2018; 23(12): 1401-7. https://doi.org/10.1111/tmi.13156
https://doi.org/10.1111/tmi.13156... , Malaysia³⁸38. Kamaruzaman NA, Leong YH, Jaafar MH, Khan HRM, Rani NAA, Razali MF, et al. Epidemiology and risk factors of pesticide poisoning in Malaysia: a retrospective analysis by the National Poison Centre (NPC) from 2006 to 2015. BMJ Open 2020; 10(6): e036048. https://doi.org/10.1136/bmjopen-2019-036048
https://doi.org/10.1136/bmjopen-2019-036... , China³⁹39. Wang B, Han L, Wen J, Zhang J, Zhu B. Self-poisoning with pesticides in Jiangsu Province, China: a cross-sectional study on 24,602 subjects. BMC Psychiatry 2020; 20(1): 545. https://doi.org/10.1186/s12888-020-02882-9
https://doi.org/10.1186/s12888-020-02882... , and South Korea⁴⁰40. Cha ES, Khang YH, Lee WJ. Mortality from and incidence of pesticide poisoning in South Korea: findings from National Death and Health Utilization Data between 2006 and 2010. PLoS One 2014; 9(4): e95299. https://doi.org/10.1371/journal.pone.0095299
https://doi.org/10.1371/journal.pone.009... ,⁴¹41. Kim HJ, Cha ES, Ko Y, Kim J, Kim SD, Lee WJ. Pesticide poisonings in South Korea: findings from the National Hospital Discharge Survey 2004-2006. Hum Exp Toxicol 2012; 31(8): 751-8. https://doi.org/10.1177/0960327111431709
https://doi.org/10.1177/0960327111431709... . In the mentioned countries, self-inflicted poisoning was the primary reason for death by pesticide poisoning. The mortality rate from suicide in Mexico has risen from 1990 to 2011; an increase of 250% was observed, and this event is most frequent in men compared with women⁴²42. Jiménez-Ornelas RA, Cardiel-Téllez L. El suicidio y su tendencia social en México: 1990-2011. Pap Poblac 2013; 19(77): 205-29.. The distribution of reasons for death from acute pesticide poisoning according to sex showed the same trends (intentionally self-inflicted poisoning>accidental poisoning>poisoning of undetermined origin>assault with pesticide); these data are contradictory with the previously reported other countries. For example, in China, suicide by pesticide poisoning was linked to females, and accidental pesticide poisoning was most frequent in males⁴³43. Wang BS, Chen L, Li XT, Xu M, Zhu BL, Zhang J. Acute pesticide poisoning in Jiangsu Province, China, from 2006 to 2015. Biomed Environ Sci 2017; 30(9): 695-700. https://doi.org/10.3967/bes2017.094
https://doi.org/10.3967/bes2017.094... ,⁴⁴44. Wang N, Jiang Q, Han L, Zhang H, Zhu B, Liu X. Epidemiological characteristics of pesticide poisoning in Jiangsu Province, China, from 2007 to 2016. Sci Rep 2020; 10(1): 1879. https://doi.org/10.1038/s41598-020-58044-0
https://doi.org/10.1038/s41598-020-58044... ; in Brazil, suicide by pesticide ingestion was common among men²⁹29. Okuyama JHH, Galvão TF, Silva MT, Grupo Datatox*. Poisoning and associated factors to death from pesticides: case-control study, Brazil, 2017. Rev Bras Epidemiol 2020; 23: e200024. https://doi.org/10.1590/1980-549720200024
https://doi.org/10.1590/1980-54972020002... . Trends in completed suicides in Mexico (from 1970 to 2007) showed that the use of a firearm (49%) and hanging (33%) were the main reported methods for suicide in men. In contrast, women select poisoning with drugs, pesticides, and lethal vapors as the primary method for suicide (59%)⁴⁵45. Hijar MM, Rascón PRA, Blanco MJ, López LMV. Los suicidios en México. Características sexuales y geográficas (1979-1993). Salud Mental 1996; 19(4): 14-21.,⁴⁶46. Borges G, Orozco R, Benjet C, Medina-Mora ME. Suicidio y conductas suicidas en México: retrospectiva y situación actual. Salud Pública Méx 2010; 52(4): 292-304.. Nevertheless, this study showed that the principal cause of death from acute pesticide poisoning in females and males was attributed to suicide. More studies are necessary to establish the risk factors of suicide by pesticide intake.

The mortality rate from acute pesticide poisoning according to age group showed more predominantly in individuals between 15 and 19 years. This trend could be explained because the 15 to 19 years group is considered the most vulnerable group for performing suicidality in Mexico⁴²42. Jiménez-Ornelas RA, Cardiel-Téllez L. El suicidio y su tendencia social en México: 1990-2011. Pap Poblac 2013; 19(77): 205-29.. Furthermore, the mortality rate from acute pesticide poisoning decreases as age increases. These results contradict those observed in other countries such as China, Malaysia, South Korea, and Brazil, which reported an increase in mortality rate from pesticide poisoning as age increases. The authors suggested that the increase in mortality rate from acute pesticide poisoning is directly associated with self-intentionally poisoning by depressive psychological states²⁹29. Okuyama JHH, Galvão TF, Silva MT, Grupo Datatox*. Poisoning and associated factors to death from pesticides: case-control study, Brazil, 2017. Rev Bras Epidemiol 2020; 23: e200024. https://doi.org/10.1590/1980-549720200024
https://doi.org/10.1590/1980-54972020002... ,³⁸38. Kamaruzaman NA, Leong YH, Jaafar MH, Khan HRM, Rani NAA, Razali MF, et al. Epidemiology and risk factors of pesticide poisoning in Malaysia: a retrospective analysis by the National Poison Centre (NPC) from 2006 to 2015. BMJ Open 2020; 10(6): e036048. https://doi.org/10.1136/bmjopen-2019-036048
https://doi.org/10.1136/bmjopen-2019-036... ,³⁹39. Wang B, Han L, Wen J, Zhang J, Zhu B. Self-poisoning with pesticides in Jiangsu Province, China: a cross-sectional study on 24,602 subjects. BMC Psychiatry 2020; 20(1): 545. https://doi.org/10.1186/s12888-020-02882-9
https://doi.org/10.1186/s12888-020-02882... ,⁴¹41. Kim HJ, Cha ES, Ko Y, Kim J, Kim SD, Lee WJ. Pesticide poisonings in South Korea: findings from the National Hospital Discharge Survey 2004-2006. Hum Exp Toxicol 2012; 31(8): 751-8. https://doi.org/10.1177/0960327111431709
https://doi.org/10.1177/0960327111431709... .

Furthermore, the analysis of suicide and suicidal behavior trends in Mexico from 1970 to 2007 showed that the highest levels of suicide and suicidal behavior were found in the 15–19 age group. An inverse relation was found with the age increase⁴⁶46. Borges G, Orozco R, Benjet C, Medina-Mora ME. Suicidio y conductas suicidas en México: retrospectiva y situación actual. Salud Pública Méx 2010; 52(4): 292-304.. This observed conduct could explain the reduction in mortality rate from acute pesticide poisoning according to age increase.

The present article is the first study about the mortality rate from acute pesticide poisoning in Mexico. The results provided epidemiological evidence to consider in developing national laws to prevent acute pesticide poisoning. Also, this study emphasizes the need for accurate records of acute pesticide poisoning.

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