Suicide and pesticide use among pesticide applicators and their spouses in the agricultural health study

Suicide and suicidality in people exposed to pesticides: A systematic review and meta-analysis

Exposure to pesticides has been proposed to be a positive association in suicide and suicidality. Many studies have explored this topic, but have reported inconsistent findings. We carried out a systematic review and meta-analysis of the now existing evidence on the association between pesticide exposure and the risk of suicide and suicidality. We searched PubMed, EMBASE and Web of Science databases for studies published up to February 1, 2023. For studies that provided detailed data, we applied quantitative meta-analysis to calculate Odds ratio (OR) with 95% Confidence Intervals (CIs) to evaluate the results. Heterogeneity among the included studies was assessed using Cochran's Q test, I² statistic and tau-squared (τ²). Publication bias was evaluated by funnel plots, Egger's test, and Begg's test. In addition, subgroup analyses according to pesticides category and geographical area were performed. 2906 studies were initially identified, and 20 studies were eventually included. Fifteen of the studies were on suicide deaths and suicide attempts, and five were on suicidal ideation. Pesticide exposure was positively related to suicide deaths and suicide attempts (pooled OR = 1.31; 95%CI: 1.04-1.64, p < 0.001) and suicidal ideation (pooled OR = 2.43; 95%CI: 1.51-3.91, p = 0.015). In the subgroup analysis, mixed pesticide type (pooled OR = 1.55; 95%CI: 1.39-1.74) increased the risk of suicide deaths and suicide attempts. The results of the analysis by geographic area showed that the risk of suicide deaths and suicide attempts with pesticide exposure was 2.27 (95%CI = 1.36-3.78), and 1.33 (95%CI = 1.14-1.56) in Asia and Europe, respectively. The risk of suicidal ideation caused by pesticide exposure in Asia and America were 2.19 (95%CI = 1.08-4.42) and 2.99 (95%CI = 1.76-5.06). In conclusion, pesticide exposure may increase the risk of suicide and suicidality based on the current evidence.

Could pesticide exposure be implicated in the high incidence rates of depression, anxiety and suicide in farmers? A systematic review

Pesticide exposure and poisoning may rise the risk of mental health problems and suicidal tendencies. To explore the potential connection between chronic occupational exposure to pesticides and depression, anxiety, and suicide-related outcomes in farmers, a systematic review was performed. Systematic review protocol is available in PROSPERO registration number CRD42022316285. A total of fifty-seven studies met inclusion criteria: twenty-nine on depression or other mental disorders, twelve on suicide (two of them on both depression and suicide), and fourteen on pesticide poisoning or self-poisoning and death. Among the fifty-seven selected studies, eighteen were conducted in Asia, seventeen in North America, fourteen in South America, seven in European Union, one in Africa, and one in Australia/Oceania. Selected studies demonstrated an increased prevalence of depressive disorders in farmworkers exposed to pesticides as well as an increased self-reported prevalence of depression in this population. Moreover, previous pesticide poisoning increased the risk estimates for depression or other mental disorders as compared with chronic pesticide exposure. Severe pesticide poisoning and multiple poisoning showed increased risks of depressive symptoms compared with milder cases. In addition, financial difficulties and poor health were positively correlated with depression. Among studies on suicide, nine of them found that suicide rates increased in areas devoted to agriculture with intensive pesticide consumption. Moreover, studies demonstrate a higher suicide risk among farmers. The present review suggests more attention to the farmer's mental health and more detailed studies on occupational exposure to the mixture of these compounds.

Alcohol use and death by suicide: A meta-analysis of 33 studies

INTRODUCTION

Decades of research show an association between alcohol use and death by suicide. However, findings on the temporal link between alcohol use and death by suicide are unclear. In the most comprehensive meta-analysis on the topic to date, we analyzed data from longitudinal studies to determine if alcohol use is a risk for death by suicide. We also explored moderators to uncover conditions where the alcohol use-suicide link is strengthened/weakened.

METHODS

Our literature search of six databases yielded 33 eligible studies involving 10,253,101 participants (community, psychiatric, and military samples).

RESULTS

Alcohol use was associated with a 94% increase in the risk of death by suicide. Specifically, random-effects meta-analysis revealed alcohol use displayed small-to-large significant risk and odds ratios with suicide for quantity of alcohol use and alcohol use diagnosis/alcohol-related problems. Meta-regression generally indicated larger effect sizes for studies with a higher percentage of women, younger age, unadjusted estimates, longer follow-up periods, military samples, and higher frequencies and quantities of alcohol use (relative to drinker/non-drinker status).

CONCLUSION

Our study highlights alcohol use as a substantive risk factor for death by suicide and underscores the importance of monitoring alcohol use among suicidal individuals and screening for suicidality among heavier alcohol users.

Use of permethrin and other pyrethroids and mortality in the Agricultural Health Study

OBJECTIVES

Pyrethroid insecticides have been linked with multiple health outcomes. One study reported an association with increased all-cause and cardiovascular mortality. Given the widespread use of pyrethroids, these findings warrant confirmation. We explored associations of permethrin/pyrethroid use with overall and cause-specific mortality among 50 665 licensed pesticide applicators in the Agricultural Health Study.

METHODS

At enrolment (1993-1997), participants self-reported information on permethrin/pyrethroid use. Information on causes of death came from linkage with death registries through 2016. We used Cox proportional hazards models to estimate HRs and 95% CIs with adjustment for potential confounders.

RESULTS

Over an average 21 years of follow-up, 19.6% (9,955) of the cohort died. We found no clear evidence that ever-use of permethrin/pyrethroid was associated with elevated overall mortality or with mortality from most causes examined. There was suggestive evidence, based on a small number of deaths among those exposed, for elevated pyrethroid-associated mortality from some neurological, respiratory and genitourinary diseases in the overall sample and from lung cancer among never-smokers.

CONCLUSION

Although based on mortality, which is also affected by survival, rather than incidence, these findings are biologically plausible, and future investigations in other populations may be warranted.

Suicide mortality among older adults in Brazil between 2000 and 2019 - estimates from the Global Burden of Disease Study 2019

INTRODUCTION

Older adults present a higher risk of suicide, and Brazil is experiencing a fast population aging. To understand the impact of demographic transition, we compared Brazilian suicide mortality rates (MR) among adults (50+ years) with global rates, those from one high-income country, and those from one middle-income country. Looking for regional disparities, the MR was analyzed among older adults (60+ years) by Brazilian states.

METHODS

This was an ecological study based on estimates from the Global Burden of Disease Study, from 2000 to 2019. Age-standardized MR and age-specific MR per 100,000 inhabitants were described, with 95% uncertainty intervals (UI).

RESULTS

During the period, the annual estimates and the declining trend in mortality were higher in the world than in the studied countries. In 2019, global age-standardized MR was 9.39 (95% UI 8.48-10.29), compared to 5.68 (95% UI 5.40-6.19), 6.01 (95% UI 5.10-7.04), and 6.63 (95% UI 6.43-6.95) in Brazil, Mexico, and England, respectively. In Brazil, despite a significant decline in national rates, stability was observed in 15 states. An increase in aging was only found for men, who presented 3-4 times higher MR than women. The states' rates presented large differences: in 2019, the rates among men aged 60-64 years varied from 7.24 (95% UI 5.31; 9.85) to 26.32 (95% UI 20.21; 34.50).

CONCLUSIONS

The smaller decline in suicide mortality among older Brazilian adults, the increasing risk with aging, and the higher mortality among men indicate the need for specific prevention policies. The variation within states suggests differences in the data quality or in socio-cultural and historical aspects, which requires further investigation.

Suicidal Ideation and Pesticide Exposure in Rural Communities of Central India

Background  This study aims to evaluate association between suicidal ideation and pesticide exposure in rural communities of Wardha district of Central rural India compared with villagers who are not exposed to it. Method  It was a cross-sectional study done in rural community of Wardha district in Central India. About 100 farmers who were exposed to pesticides and 100 controls who were not exposed to pesticides were included. A Semistructured proforma to record sociodemographic variables and Indian version of the Self Reporting Questionnaire-20 was used. Results  Of these 200 subjects, data were available for 85 farmers in study group and 74 in control group. In the farmers group, 31% of farmers had suicidal ideas, while 8% of controls felt like ending their life. Conclusion  Measures must be taken to store pesticides at a safer place thus reducing long-term exposure. Organic farming is a better choice to avoid suicidal ideas.

Proposal for the Inclusion of Tobacco Use in Suicide Risk Scales: Results of a Meta-Analysis

There is an association between smoking and suicide, even though the direction and nature of this relationship remains controversial. This meta-analysis aimed to evaluate the association between smoking and suicidal behaviours (ideation, planning, suicide attempts, and death by suicide). On 24 August 2020, we searched the PubMed, Cochrane library, Scopus, Web of Science, TRIP, and SCIENCE DIRECT databases for relevant articles on this topic. Twenty prospective cohort studies involving 2,457,864 participants were included in this meta-analysis. Compared with never smokers, former and current smokers had an increased risk of death by suicide (relative risk [RR] = 1.31; 95% CI [1.13, 1.52] and RR = 2.41; 95% CI [2.08, 2.80], respectively), ideation (RR = 1.35; 95% CI [1.31, 1.39] and RR = 1.84; 95% CI [1.21, 2.78]), and attempted suicide (RR = 1.27; 95% CI [0.56, 2.87] and RR = 1.71; 95% CI [0.73, 3.97]). Moreover, compared to never smokers, current smoker women (RR = 2.51; 95% CI [2.06-3.04] had an increased risk of taking their own life (Q = 13,591.53; p < 0.001) than current smoker men (RR = 2.06; 95% CI [1.62-2.62]. Furthermore, smoking exposure (former and current smokers) was associated with a 1.74-fold increased risk (95% CI [1.54, 1.96]) of suicidal behaviour (death by suicide, ideation, planning, or attempts). Thus, because of the prospective relationship between smoking and suicidal behaviours, smoking should be included in suicide risk scales as a useful and easy item to evaluate suicide risk.

Suicide in Spanish Farmers in Two Geographical Areas with Differing Rates of Pesticide Use

This study assesses whether farmers' suicides were associated with the pesticide use in Spain. The cohort study followed 9.5 million men aged 20-64 years who were employed in 2001. The mortality among farmers and non-farmers during the period 2001-2011 was estimated in a geographical area with high pesticide use and in an area with low pesticide use. For three major causes of death (suicide, unintentional accidents, and rest of causes of death), we estimated the age-standardized mortality rates with 95% confidence intervals (CI) between farmers and non-farmers in both areas. Farmers in the high pesticide use area showed a lower mortality rate of suicide and unintentional accidents than farmers in the rest of Spain, with mortality rate ratios of 0.74 (95% CI 0.65-0.85) and 0.57 (95% CI 0.52-0.62), respectively. Our findings on pesticide use and farmers' suicide are different from those observed in several previous investigations.

A Scoping Review of Non-Occupational Exposures to Environmental Pollutants and Adult Depression, Anxiety, and Suicide

PURPOSE OF REVIEW

Despite a call for better understanding of the role of environmental pollutant influences on mental health and the tremendous public health burden of mental health, this issue receives far less attention than many other effects of pollutants. Here we summarize the body of literature on non-occupational environmental pollutant exposures and adult depression, anxiety, and suicide-in PubMed, Embase, Web of Science, and PsychINFO through the end of year 2018.

RECENT FINDINGS

One hundred twelve articles met our criteria for further review. Of these, we found 88 articles on depression, 33 on anxiety, and 22 on suicide (31 articles covered multiple outcomes). The earliest article was published in 1976, and the most frequent exposure of interest was air pollution (n = 33), followed by secondhand smoke (n = 20), metals (n = 18), noise (n = 17), and pesticides (n = 10). Other exposures studied less frequently included radiation, magnetic fields, persistent organic pollutants (POPs), volatile organic compounds, solvents, and reactive sulfur compounds. The current literature, although limited, clearly suggests many kinds of environmental exposures may be risk factors for depression, anxiety, and suicide. For several pollutants, important limitations exist with many of the studies. Gaps in the body of research include a need for more longitudinal, life-course studies, studies that can measure cumulative exposures as well as shorter-term exposures, studies that reduce the possibility of reverse causation, and mechanistic studies focused on neurotoxic exposures.

Risk for Depressive Symptoms and Suicide Among U.S. Primary Farmers and Family Members: A Systematic Literature Review

Background: About 84% of the agriculture, fishing, and forestry occupational sector is comprised of farmers. This sector is at high risk for suicide in the United States. Recent disasters and trade upheavals may make farmers and their families more vulnerable to depression and suicide. This review focused on the risk for depression and suicide among United States’ primary farm operators and their families. Methods: A systematic search of the literature published between January 2000 and June 2019, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted. Results: A total of 30 articles met full inclusion criteria. Seventeen reports emanated from the midwest. Twenty studies used a cross-sectional design, primarily assessing a convenience sample or random stratified sample from a limited geographic area. We discovered only one intervention evaluation study. Depressive symptoms were assessed as part of the studies, but it was not the major focus. A variety of instruments measured depressive symptoms, with the Centers for Disease Control Epidemiologic Studies—Depression (CES-D) Scale used more frequently than other scales. Thirteen studies focused on the relationship between pesticide/chemical exposure and depression or suicide risk. Increased stress, poor physical health, compromised financial position, and previous injury were among the leading indicators of depression. Conclusion/Application to Practice: The limited number of studies that was discovered identified the need for more robust science where the risk for depression and suicide is the primary focus of the study and for intervention studies grounded in science. Occupational health providers should be vigilant about farm exposure and be aware of factors that may influence depressive symptoms of workers who operate farm establishments.

A study of risk factors for the possible cases of acute occupational pesticide poisoning of orchard farmers in some parts of south Chungcheong province

BACKGROUND

The objective of the present study is to identify differences in the prevalence of acute occupational pesticide poisoning across Korean orchard farmers' farming characteristics and the risk factors that have an effect on acute occupational pesticide poisoning.

METHODS

For 3 years (2014, 2015, and 2017), a questionnaire survey was conducted on 394 orchard farmers in some parts of south Chungcheong Province in relation to pesticide poisoning. 323 orchard farmers who responded to acute occupational pesticide poisoning were included for final analysis. With acute occupational pesticide poisoning as the dependent variable, a χ2 test and a multiple logistic regression analysis were conducted.

RESULTS

The results of the prevalence of acute occupational pesticide poisoning across farming characteristics showed that the group wearing 4 or more pesticide personal protective equipment (PPE) had a lower prevalence of acute occupational pesticide poisoning than the group wearing 3 or less pesticide PPE (p < 0.05). Furthermore, an analysis by area of fruit farming revealed that the group with more than 12,000m2 in the area of fruit farming had a higher prevalence of acute occupational pesticide poisoning (p < 0.05). Orchard farmers mainly use a speed sprayer to spray pesticides, and the speed sprayer can be categorized by presence of cabin. The analysis of the prevalence of acute occupational pesticide poisoning by speed sprayer's cabin existence found that existence of speed sprayer's cabin did not show a statistically significant difference in the prevalence of acute occupational pesticide poisoning.

CONCLUSIONS

The present study analyzed the prevalence of acute occupational pesticide poisoning depending on the speed sprayer's cabin existence and found no significant difference. The fact that famers using the cabinless style speed sprayer shows a higher percentage in wearing PPE than those using the cabin style speed sprayer is suggested to elucidate the result. As the first study in Korea which examined the prevalence of acute occupational pesticide poisoning by speed sprayer's cabin existence, the present study proposes the expected effect that increase of wearing pesticide PPE along with employ of speed sprayer's cabin can reduce the prevalence of acute occupational pesticide poisoning among orchard farmers.

Occupational exposure to pesticides: development of a job-exposure matrix for use in population-based studies (PESTIPOP)

Occupational exposure to pesticides concerns a wide population of workers not only in agriculture. The reliability of self-reported information on pesticide use is questionable because of the diversity of use. The PESTIPOP job-exposure matrix has been designed to assess pesticide occupational exposure in the general population. The matrix is composed of two axes: the first axis corresponding to jobs (combinations of occupations and industries) and the second one to pesticide exposure. The estimated exposure metric is the probability of exposure coupled with a reliability assessment (low, medium or high). These metrics were defined by combining different sources: (1) an a priori expert assessment (Agricultural industry experts); (2) data from a multicenter case-control study on brain tumors in the general population (occupational history, specific questionnaires); and (3) an a posteriori expert assessment based on the data of a case-control study. So far, 2559 jobs have been identified and 209 (8%) were found to be exposed to pesticides. Jobs with agricultural exposure had a higher exposure probability than jobs with non-agricultural exposure (wood preservation, park maintenance, pest control). Indirect exposure was more frequent than direct exposure. The PESTIPOP matrix will be transcoded into international classifications for use in epidemiological studies.

Pesticides

There is growing evidence about the influence of chemical exposures on specific molecular systems and mechanisms involved in cognitive and mental function. Evidence is also emerging about the negative impact of these chemical exposures on mental health, including depression, suicide, and other risks. Despite the growing appreciation of these factors, however, little attention has been paid to the ethical and social implications of their interactions. Drawing on recent work that argues for an environmental neuroethics approach that explicitly brings together ethics, environment, and conditions of the central nervous system, this article focuses on these critical issues for pesticides specifically.

Use of job-exposure matrices to estimate occupational exposure to pesticides: A review

The health effects of pesticides have been extensively studied in epidemiology, mainly in agricultural populations. However, pesticide exposure assessment remains a key methodological issue for epidemiological studies. Besides self-reported information, expert assessment or metrology, job-exposure matrices still appear to be an interesting tool. We reviewed all existing matrices assessing occupational exposure to pesticides in epidemiological studies and described the exposure parameters they included. We identified two types of matrices, (i) generic ones that are generally used in case-control studies and document broad categories of pesticides in a large range of jobs, and (ii) specific matrices, developed for use in agricultural cohorts, that generally provide exposure metrics at the active ingredient level. The various applications of these matrices in epidemiological studies have proven that they are valuable tools to assess pesticide exposure. Specific matrices are particularly promising for use in agricultural cohorts. However, results obtained with matrices have rarely been compared with those obtained with other tools. In addition, the external validity of the given estimates has not been adequately discussed. Yet, matrices would help in reducing misclassification and in quantifying cumulated exposures, to improve knowledge about the chronic health effects of pesticides.

Anxiety and depression following cumulative low-level exposure to organophosphate pesticides

Previous research suggests that individuals with a prior history of pesticide poisoning are at increased risk of psychiatric disorder (Freire and Koifman, 2013), but findings regarding the impact of cumulative low-level exposure are inconsistent. The aim of the current study was to investigate whether sheep farmers with a history of low-level exposure to organophosphate pesticides (1) report a higher level of psychological distress on subjective symptom questionnaires, compared to unexposed controls (2) also meet internationally agreed diagnostic criteria for a psychiatric disorder more often than unexposed controls. 127sheep farmers were evaluated and compared to 78 unexposed controls, matched in terms of gender, education, level of intelligence, working status and area of residence. Both self-report measures and structured clinical interviews were used to assess mental health. The exposed cohort reported significantly higher rates of anxiety and depression when self-report questionnaires were used to evaluate mood, even when stressful life events, demographic and physical health factors were taken into account. However, when diagnostic interviews were used to assess mood, this pattern only held true for anxiety.

Suicidal ideation and occupational pesticide exposure among male farmers

BACKGROUND

The occupation of farming has been reported to be associated with a high suicide rate, and suicidal ideation is an important risk factor for suicide. The objective of this study was to explore the association between occupational pesticide exposure or poisoning history and suicidal ideation among male farmers in South Korea.

METHODS

Through a nationwide sampling survey, a total of 1958 male farmers were interviewed in 2011 in South Korea. Detailed occupational pesticide exposure and pesticide poisoning information were obtained from face-to-face interviews. Suicidal ideation was defined as whether they had thought of harming themselves or trying to take their own lives over the preceding year. Logistic regression analyses were conducted to examine the effect of pesticide poisoning on suicidal ideation.

RESULTS

Among all farmers, 4.7% (n=92) reported suicidal ideation in 2010. After controlling for potential confounders, lifetime hospitalization due to pesticide poisoning showed a 2.48-fold increase in risk (95% CI: 1.26, 4.91). Those with multiple poisonings showed more significant associations with suicidal ideation (OR=2.33 for once, OR=3.02 for more than once). Moderate- or severe-symptom severity of acute pesticide poisoning cases (OR=2.23; 95% CI: 1.21-4.11) also showed increased risks of suicidal ideation than the milder classes did. However, no significant association was identified with cumulative lifetime pesticide application and suicidal ideation.

CONCLUSIONS

Our findings suggest that risk of suicidal ideation is related to occupational pesticide poisoning among male farmers.

Suicide by occupation: systematic review and meta-analysis

BACKGROUND

Previous research has shown that those employed in certain occupations, such as doctors and farmers, have an elevated risk of suicide, yet little research has sought to synthesise these findings across working-age populations.

AIMS

To summarise published research in this area through systematic review and meta-analysis.

METHOD

Random effects meta-analyses were used to calculate a pooled risk of suicide across occupational skill-level groups.

RESULTS

Thirty-four studies were included in the meta-analysis. Elementary professions (e.g. labourers and cleaners) were at elevated risk compared with the working-age population (rate ratio (RR) = 1.84, 95% CI 1.46-2.33), followed by machine operators and deck crew (RR = 1.78, 95% CI 1.22-2.60) and agricultural workers (RR = 1.64, 95% CI 1.19-2.28). Results suggested a stepwise gradient in risk, with the lowest skilled occupations being at greater risk of suicide than the highest skill-level group.

CONCLUSIONS

This is the first comprehensive meta-analytical review of suicide and occupation. There is a need for future studies to investigate explanations for the observed skill-level differences, particularly in people employed in lower skill-level groups.