Association between pesticide exposure and neurobehavioral performance of agricultural workers: A cross‐sectional study

Abstract Background Pesticide exposure has affected humans’ health, especially those directly in contact with a pesticide like agricultural workers. Here, we sought to see a link between pesticide exposure and cognitive impairment among male agricultural workers. Methods We selected 18–60 years old 100 male agricultural workers who came for their health check‐up in the hospital's out‐patient department from August 2020 to May 2021. Standardized questionnaires (German Q18 questionnaire) and WHO Neurobehavioral Core Test Battery were used to examine the neurobehavioral performance of the individuals. The data were presented in a descriptive manner and statistically examined using the chi‐square test. Results The male agricultural workers’ neurobehavioral performance was 46% normal and 54% abnormal. Headaches, impaired focus, short memory, weariness, palpitation, and numbness were the most prevalent neurobehavioral impairments. The chi‐square test revealed that spraying frequency (p =.010), personal protective equipment (PPE) use (p < .001), and smoking habits (p =.006) were all linked to neurobehavioral performance, while spraying duration (p =.804), working years (p =.234), pesticide types (p =.816), and spraying time (p =.867) were not linked to neurobehavioral performance. Conclusion We found that pesticide exposure has a certain role on neurobehavioral performance in adult male agricultural workers as more people have been affected; however, a considerable number of confounding factors might have played a significant role in giving rise to such results. The government should be concerned about farmer's neurobehavioral performance and implement different approaches to minimize the use of pesticides so that agricultural workers can work without any mental health problems.


INTRODUCTION
Pesticides are commonly used as toxic chemicals in agriculture-related fields to kill various kinds of pests (insects, fungi, microorganisms, etc.) and are thus used to enhance crops, livestock, and farm productivity. Pesticides have various adverse effects on the health of the individuals whether exposed for an extended period or short time, which could lead to numerous diseases such as cancers, asthma, allergies, hypertension, neurological disease, psychiatric disease, and even pregnancy-related issues (low birth weight, deformities, and abortions) (Forté et al., 2021;Hongsibsong et al., 2017;Kaur & Kaur, 2018;Kim et al., 2019).
Agriculture workers use pesticides to improve their crop production; therefore, they are one of the highly exposed groups of people.

Study population
Our cross-sectional study of pesticide exposures was conducted on 18-60 years old 100 participants who came to the hospital for their

Data collection
The German Q18 questionnaire was used to assess neurobehavioral performance (the questionnaire is available in English, and we translated English to the local Nepalese language orally to the participants) (Ihrig et al., 2001). It comprises 18 questions that are used to assess the symptoms of neurobehavior, in which cut-off point 5 was implemented to determine the altered neurobehavior performance, which was recommended by a previous study to use in the German Q18 questionnaire (Ihrig et al., 2001). In addition, health professionals used the WHO Neurobehavioral Core Test Battery (WHO-NCTB), which comprises the Digit Span, Digit Symbol, Pursuit Aiming, and Trail Making tools to assess neurobehavioral function (Anger et al., 1994). Respondents completed the test in 10 min, starting with the Digit Span Test, the Digit Symbol Test, the Pursuit Aiming Test, and finally, the Trail Making Test. If all of the score tests were over 40, the neurobehavioral performance was categorized as normal, and if one of the score tests was below 40, it was classified as abnormal (Anger et al., 1994;Ihrig et al., 2001). As our study aims to explore whether those agricultural field workers have abnormal neurobehavior function, we used the above-mentioned cut-off points to differentiate between normal and abnormal neurobehavior functions.

Statistical analysis
The data were presented in a descriptive manner using frequencies and percentage ages to show participants' characteristics, pesticide exposure factors, and neurobehavioral function. Using chi-square tests, the relationship between pesticide exposure and neurobehavioral performance was examined. IBM SPSS 23.0 (Chicago, IL, USA) was used to conduct all analyses, and statistical significance was defined as a p-value of less than .05.

RESULTS
The group of 48 to 57 years old had the most subjects out of the four age groups, and 55% of participants had a normal nutritional status.
While half of the participants were moderate smokers, three fifths of the subjects did not consume alcohol, and a very large majority of the participants (87%) were married ( Table 2). The German Q18 questionnaire was used to screen for neurobehavioral problems ( ing Test all showed a significant connection with the neurobehavioral performance, with p < .001 being the most significant (Table 4).
The findings of the chi-square test were used to investigate the link between pesticide exposure parameters and farmers' neurobehavioral performance (see Table 4). Pesticide types, spraying times, spraying duration, or working years had no significant connection with neurobehavioral performance (p-values = .816, .867, .804, and .234, respectively). However, there was a correlation between neurobehavioral performance and pesticide spraying frequency (p =.010), personal protective equipment (p = .001), and smoking habit (p =.006) ( Table 5).

DISCUSSION
Our study showed that more than half of the recruited agricultural workers had an altered neurobehavioral function, although we could not find any correlation of pesticide types, pesticide spraying time, and working years in the agriculture field with altered neurobehavioral functions. However, there was a definite link between smoking habits, use of personal protective equipment (PPE), and pesticide spraying frequency with cognitive deficits.
Emerging studies documented that acute and chronic pesticide exposure is associated with adverse influences and hostile health conditions that directly or indirectly lead to many diseases or disorders, In our study, one of the reasons why we have found neurobehavioral deficits is that the agricultural workers included in our study were mostly 48−57 years of age. In addition, beyond 28 years of age, nerve function declines every 5 years, with the decline in nervous system performance because the harmful chemicals from the pesticide go to the brain cells through the various biological mechanism and cause deterioration of nerve cell, leading to altered neurobehavioral functions (Jett, 2011;Rohlman et al., 2012). Studies have also reported that pesticides cause alterations in neurotransmitter systems, ion channels, mitochondrial function, cholinergic mechanism, and free radical production, which all lead to dysfunctional neurobehavior functions in individuals. In addition, respondents with abnormal nutritional status had inferior neurobehavioral performance than those with an adequate nutritional condition due to endocrine disruption (LaVerda et al.,

2015).
A relationship was established between the use of personal protection equipment and neurobehavioral function in the study. The majority The poor use of PPE is correlated with lack of authentic PPE availability, negative attitudes, and feeling of discomfort while wearing PPE (Ismail et al., 2017). The usage of PPE by farmers is linked to their cholinesterase levels. Spraying using complete PPE is essential to avoid pesticide exposure and is thought to reduce the risk of pesticide poisoning among farmers. Therefore, if there is any mistake while wearing PPE and spraying for a longer time, it might affect the individual's health.
There was a significant link between smoking and neurobehavioral function in our study. Cigarette smoking harms human health because it contains nicotine, which substantially impacts brain function, espe-cially in high doses, by producing endorphins, leading to nerve-related issues (Benowitz, 2009 (Anger et al., 2000). Third, there was no comprehensive analysis of the pesticides used, and no quantitative biomarker measurements were taken. Fourth, we did not analyze scalar information of actual scores on the individual test.

CONCLUSION
Even though many cofounding factors might have played a role in the outcome of this study, there is undoubtedly a negative correlation between pesticide exposure and the neurobehavioral performance of adult male agricultural workers. As a corollary, the government should be vigilant about farmers' neurobehavioral performance and pursue various strategies for reducing pesticide use so that agricultural workers can work without mental health issues. The government must also provide frequent pesticide counseling, including selecting appropriate pesticides, correctly administering them, and informing farmers about the importance of wearing PPE. In the future, pesticide exposure and psychiatric diseases should be probed further, with a detailed and quantitative investigation of the substances or mixes of pesticides implicated in an exposure. Furthermore, we suggest that psychological testing should be undertaken in pesticide-exposed populations.

CONFLICT OF INTEREST
The authors declare no conflict of interest.

FUNDING INFORMATION
None.

DATA AVAILABILITY STATEMENT
Data/reports are available from the authors upon reasonable request and with the participant's permission.