Research

Pesticide Spraying and Reduced Cholinesterase Activity among Hill Tribe Farmers in

Kowit Nambunmee,1,2 Background. Farming is an important occupation in Thai hill tribe communities, which are 1 often remote, and lack other economic opportunities along with basic educational, health Tharinya Kawiya, Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 Richard L Neitzel,3 care, and occupational health and safety services. Additionally, these communities have a Prapamon Seeprasert1,2 unique culture and language. Objectives. The present study was conducted in northern Thailand to evaluate pesticide 1 School of Health Science, Mae Fah Luang exposures and associated health impacts among hill tribe farmers, and to compare them to University, , Thailand Thai farmers. 2 Urban Safety Innovation Research Methods. Lahu hill tribe farmers in a mountain community were recruited by public health Group (USIR), Mae Fah Luang University, hospital staff, along with a reference group of lowland Thai farmers. Participants completed Chiang Rai, Thailand a survey on demographic factors and work practices, and blood and urine samples were 3 Department of Environmental Health collected by a trained nurse. Acetylcholinesterase activity (AChE) was quantified to assess Sciences, School of Public Health, pesticide exposure, whereas liver and kidney functions were evaluated using clinical University of Michigan, Michigan, USA biomarkers. Results. A large fraction (nearly 50%) of Lahu farmers were illiterate and could not speak Corresponding author: Thai. Thai farmers worked fewer hours per week (39.4) than did Lahu farmers. Among Lahu Kowit Nambunmee farmers, AChE levels were significantly lower (worse) than those of Thai farmers. However, [email protected] other health outcomes in these populations were similar. Formal education and language skills were not associated with pesticide exposures or health outcomes. Pesticide spraying was found to be a significant predictor of reduced AChE (OR=8.5, 95% CI 1.1-69.6). Conclusions. Pesticide exposures are a significant occupational health hazard among Thai hill tribe farmers. Training, potentially delivered by community health volunteers, is needed to communicate safe pesticide work practices to these farmers. Introduction Participant Consent. Obtained Ethics Approval. The study protocol was approved by the Institutional Review Board of Mae Farming is a major occupation and Fah Luang University (REH-61080). source of family income in Thailand. Competing Interests. The authors declare no competing financial interests. The northern region of Thailand has Keywords. Lahu hill tribe, farmer health, acetylcholinesterase, language communication, excellent conditions for growing high exposure assessment, pesticide spraying. quality crops and has the highest rate Received April 27, 2021. Accepted May 24, 2021. of corn cultivation among all regions J Health Pollution 31: (210908) 2021 of Thailand. A total of 793 333 hectares © Pure Earth are harvested for corn in upland areas of the region for corn cultivation between May and October.1

Pesticides are often used to enhance agricultural production in Thailand; of workplace health and safety among is a marker to indicate exposures 110 000 tons of pesticides were self-employed and informal workers, to organophosphates (OP) and imported into the country in 2007, no administrative structure to provide carbamates (CA), which are the which increased to 172 000 tons occupational safety and health services most commonly used families of in 2013.2 Most Thai farmers are to these workers has been established.4 pesticides.5 Lower AChE levels have self-employed or work informally, Given these circumstances, been associated with OP and CA and pesticide use among informal pesticide use is an ongoing potential pesticide exposures.5 Measurement workers is not regularly monitored.3 occupational risk among farmers. of AChE activity can indicate OP Although the Thai government has and CA exposure before permanent provided guidance to raise awareness Acetylcholinesterase activity (AChE) health outcomes manifest,6 and

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can be used to produce estimates of Abbreviations chronic exposure. This biomarker has been used previously in a number of AChE Acetylcholinesterase activity GER Glomerular filtration rate populations, including Thai farmers, a group in which associations were FECa Fractional excretion PPE Personal protective observed between AChE levels and of calcium equipment health outcomes.7 An important advantage of this biomarker is that Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 it can be processed quickly with basic laboratory equipment, which makes field-based pesticide exposure screening more feasible. Given that pesticide exposure Tha Khao Plueak Health Promoting may represent a significant health Hospital staff using the same methods; Chiang Rai is a province in northern hazard among informal workers and 86 Thai farmers were identified in this Thailand located close to the border minority groups with limited access way and approached to participate. of Myanmar and Laos. Migrants from to education and basic services in The Thai farming community was these two bordering countries, known Thailand, the present study was located more than 130 km away from as hill tribes, settled in Chiang Rai a conducted to assess health status and the Lahu study community in a flat century ago.8 There are six main hill the relationship between pesticide lowland area (mean elevation 388 m tribe groups in Chiang Rai: Akha, exposures and agriculture practices above sea level). Lahu, Hmong, Yao, Lisu, and Karen. among Lahu farmers in Chiang Rai, The Lahu tribe is the second most and to compare their results to those Sample collection populous population among hill tribe from a group of Thai farmers. minorities of Thailand.9 The Lahu Farmers in the two communities divide themselves into subgroups, such Methods were provided with an overview of as the Lahu Na (Black Lahu), Lahu Nyi the study, and the 100 interested (Red Lahu), Lahu Hpu (White Lahu), The study protocol was approved by individuals provided informed consent and Lahu Shi (Yellow Lahu); these the Institutional Review Board of Mae and were enrolled into the study. subgroup names refer to the colors of Fah Luang University (REH-61080). Individuals unable to provide written each subgroup’s traditional clothing.10 All study participants were 21 years consent indicated consent with a Lahu hill tribes have a unique and and older and resided in Chiang Rai thumbprint. All subjects participated distinct culture, and their main Province. Staff from the Mae Chedi in work observations and provided occupation is farming (primarily corn, Mai Health Promoting Hospital helped urine and blood samples. To increase rice, and flowers) in mountainous recruit Lahu farmers in the survey community engagement, a community areas. 9 This activity provides financial area. The Lahu study community was leader and community health support and can be done locally, located nearly 100 km from Chiang volunteer were invited to join the without the need to travel outside hill Rai in a mountainous area (770 m research team during data collection, tribe villages. However, these villages about sea level) (Figure 1). Family following consent of the participants. are commonly located in remote areas, information on record at the Mae with limited facilities for education, Chedi Mai Health Promoting Hospital We assessed pesticide exposures electricity, clean water and health care from 2018 was used to identify Lahu and potential adverse health effects services. Pesticides are commonly farmers to approach for participation; among participating farmers using used by Lahu farmers to increase crop 146 Lahu farmers were identified in a combination of survey data, yields. The companies selling these this way. One hundred Lahu farmers biomarker collection and analysis, and pesticides provide manuals and/or agree to participate, and Mae Chedi environmental sampling. The survey guideline labels, but this information Mai Health Promoting hospital staff used was based on a previous study is not used by most farmers due to then scheduled data and sample of worker health in a marginalized literacy barriers. Limited literacy collection. A Lahu language translator community (Supplemental Material).12 and lack of formal education may from the Lahu community was used The survey was administered at increase pesticide exposure risks,11 and to interview participants who were the local community center in the awareness of occupational hazards not able to speak Thai. A reference two communities and took 35- appears to be low in this population. group of Thai farmers was recruited by 45 minutes to complete. Survey

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Figure 1 — Survey area for Lahu farmers in Ban Huai Muang, Wiang Pa Pao District and Thai farmers in Ban Phan Suek,

questions addressed demographic BD Vacutainer® EDTA tubes. Serum aspartate aminotransferase (AST), and factors, farm practice, pesticide use, tubes were left at room temperature complete blood counts were measured self-reported health and presence of for 2 hours to allow blood clotting by Meng Rai Laboratory in Chiang several pesticide-related neurological and then centrifuged at 4 500 rpm Rai, which is accredited by the Medical symptoms, including numbness, for 15 minutes. Serum was separated Technology Council of Thailand. tingling, and trembling. into cryo-vials. All blood and urine Analyses were completed with an XN- samples were stored at -80°C for 550 Hematology Analyzer (Sysmex Trained nurses collected 10 mL of further analysis. Corporation, Kobe, Japan) and urine and 10 mL of venous blood COBAS INTEGRA® 400 Plus Analyzer from workers. Five ml of blood was Blood and urine analysis (Roche, Basil, Switzerland). Levels collected in BD Vacutainer® Plus of AChE were analyzed from whole venous blood collection serum tubes, Urinary creatinine, urinary calcium, blood using the Ellman method.13 and another 5 ml was collected in serum creatinine, serum calcium, Levels <8 200 units/liter (U/L) were

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classified as reduced AChE activity Statistical analyses = 27.9, Lahu = 31.3%). There was no and presumed high pesticide exposure. identified association between PPE use Levels >8 200 U/L were classified as We calculated summary statistics of and reduced levels of AChE among the normal AChE activity.14 survey-derived demographic data farmers in the present study. across the entire population. We Blood chemistry test compared distributions of participants The vast majority of Thai (85%) and according to ethnicity, gender, Lahu (80%) farmers had worked in A battery of blood parameters was education, language skills, working this occupation >10 years. A much Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 used to assess health impairment. hours, farm type, PPE use category, larger fraction of Lahu farmers grew Anemia was defined in men as health status, AChE level, neurological corn (84.4%) compared to Thai hemoglobin (Hb) <13 mg% and symptoms, blood chemistry, and farmers (47.4%). Fewer than 10% of in women as Hb <12 mg%. Liver pesticide use. These comparisons Thai and Lahu farmers used no PPE injury was defined as AST >40 U/L. were done using chi-square or Fisher’s during farming activities (i.e., were Glomerular filtration rate (GFR) was exact tests for categorical variables, categorized as PPE-0) (Table 1), and estimated from serum creatinine levels and independent Student’s t-test for roughly half of farmers in the two using the Modification of Diet in Renal continuous variables. A series of groups were categorized in the PPE-4 Disease (MDRD) equation: GFR <90 logistic regression models were used category. Roughly 1-2% of farmers in ml/min/1.73 m2 was defined as kidney to estimate the odds ratio (OR) for the two groups reported being in poor impairment.15 Fractional excretion reduced levels of AChE (i.e., level <8 health. of calcium (FECa), the percentage 200 U/L) associated with different of calcium clearance as a fraction of pesticide use activities, neurological Thai farmers had a significantly higher creatinine clearance, was calculated symptoms, and blood test results. mean age than Lahu farmers (51.2 vs according to Steward 2012,16 and FECa These models were adjusted for age, 39.0 years old, p<0.001), but reported >2% was interpreted as abnormally ethnicity (i.e., Thai vs. Lahu), PPE fewer working hours per week (39.4 high excretion of Ca via urine.17 category, working hours per week, and hours vs. 44.0 hours, respectively) education status. All analyses were (Table 2). Lahu farmers had a Personal protective equipment use conducted using the Statistical Package significantly higher mean hemoglobin for the Social Sciences (SPSS) program level than did Thai farmers (Hb: 14.9 Self-reported use of personal (SPSS, Inc. IBM SPSS, Armonk, NY). vs 13.6 mg%, respectively, p<0.001), protective equipment (PPE) was used and a significantly lower mean AChE to group farmers into PPE categories. Results level (10,730.2 vs 13,834.2 U/L, This method was applied from a respectively p<0.001). 2020 study by Mueangkhiao et al.18 A total of 100 Lahu farmers The PPE-0 category was assigned participated in the study; one was No relationship was observed between to farmers who reported no use of excluded from data analysis because reduced AChE activity and language PPE (i.e., reported PPE protection of kidney disease. Of the 99 remaining communication or harmful perception percentage = 0). The PPE-1 category Lahu farmers, 95 (96%) were Black of pesticides (Table 3). The prevalence was assigned to farmers who reported Lahu and 4 (4%) were Red Lahu.10 of AChE <8 200 U/L among subjects using face shields, fabric/leather Forty-three Thai farmers participated who reported health problems was gloves, or other protective clothing in the study. The proportion of not significantly different than among (protection percentage = 20). The females in the Lahu and Thai groups participants with no reported health PPE-2 category was assigned to was similar (Table 1). Among the problems. However, AChE <8 200 U/L farmers who reported using cartridge participants, 41.4% of Lahu farmers prevalence was significantly higher respirators, gas masks, or disposable and 9.3% of Thai farmers were among participants with secondary outer clothing (protection percentage illiterate. Just over 14% of Lahu school education than among illiterate = 30), PPE-3 was assigned to farmers farmers could not speak Thai, and subjects (29.4 vs 8.9%, respectively, who reported using chemical resistant nearly 50% could not read Thai. A p<0.028). In addition, mean AChE rubber gloves (protection percentage significantly higher fraction (65.1 vs level among participants with a history = 40), and PPE-4 was assigned to 24.2%, p<0.001) of Thai farmers drank of pesticide spraying was significantly farmers who fell into both the PPE- alcohol compared to Lahu farmers, lower than that of participants with no 1 and PPE-3 categories (protection while smoking rates did not differ history of pesticide spraying (Figure percentage = 60). significantly between the groups (Thai 2a). AChE levels did not show a

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Table 1 — Population Characteristics, Farm Practices and Overall Health Status of Surveyed Farmers (N=142)

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Table 2 — Comparison of Age, Working Hours per Week, Acetylcholinesterase Activity, Hemoglobin, Aspartase Aminotransferase, Fractional Excretion of Calcium, and Glomerular Filtration Rate Between Thai and Lahu Farmers (N=142)

significant relationship with pesticide reduced AChE activity was found in occupational hazard for farmers, and mixing or storing (Figure 2b and 2c). this analysis. can occur during storing, mixing and spraying activities.19 Health outcomes As shown in Table 4, logistic regression Discussion associated with acute pesticide was used to calculate the odds ratio exposure include, dizziness, cramps, (OR) comparing reduced AChE In 2012, there were 216 hill-tribe nausea, vomiting, abdominal pain, prevalence between presence and villages with a population of 48 835 in numbness, fatigue, headache, excessive absence of neurological symptoms, .9 This population salivation, respiratory problems and blood chemistry test results and has limited access to education blurred vision.20 Chronic health pesticide use. A subject with a history and other services due to their outcomes resulting from pesticide of pesticide spraying had a 8.546 mountainous location and cultural exposure include kidney and liver times chance of having reduced AChE differences, and these conditions result dysfunction and increased cancer (1.050-69.557 95% C.I., p=0.045) after in increased health risks, including risk.18 In Thailand, the rate of adjusting for age, ethnic group, PPE risk of exposure to occupational pesticide-related morbidity increased category, working hours per week and hazards. Most hill tribe farmers are from 2.5 to 9.0 per 100 000 population education. A relationship between informal workers who do not have from 2010 to 2015, with 70.8% of tingling and reduced AChE was not the infrastructure and resources cases occurring in individuals between found in this analysis, which implies necessary to create healthy workplace the ages of 15 and 59.21 This situation the presence of a confounding factor environments. suggests that safe practical guidelines in this relationship. No relationship are needed to reduce pesticide between liver or kidney injury and Exposures to pesticides are a major exposures among farmers in Thailand.

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Table 3 — Relationship Between Reduced Acetylcholinesterase (AChE) Activity, Language Skills, Education, Pesticide Danger Perception, and Self-reported Health Problems in Thai and Lahu Farmers (N=142)

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Figure 2 — Acetylcholinesterase activity level comparison between groups involved with (+) and not involved with (-) different pesticide use activities

Table 4 — Logistic Regression Analysis to Assess Risk of Reduced Levels of Acetylcholinesterase Activity (<8,200 U/L) Associated with Neurological Symptoms, Blood Chemistry, and Pesticide Use*

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and ingestion resulting from three basic activities: mixing and loading, spraying, and storing. In the present study, only pesticide spraying was significantly related to reduced AChE. The prevalence of AChE <8 200 U/L (indicating reduced AChE) was six times higher (25.6%) for farmers who Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 sprayed pesticides compared to those who did not (4.0%). There was an 8.5 (95% CI 1.05-69.6) OR for reduced AChE among farmers who sprayed pesticides, adjusting for age, ethnicity, PPE category, working hours per week, and education status. Spraying may result in a longer exposure duration compared to other pesticide-related activities, which may result in greater doses of pesticides.22 Other studies have reported a substantial body burden of pesticides among pesticide sprayers.23 Figure 3 —Thai farmer using personal protective equipment during pesticide spraying Pesticide spraying increases pesticide exposure via inhalation and dermal absorption. Dermal absorption may occur as a result of splashes, spills, or The present study evaluated pesticide- for age in the present study. We did spray drift, whereas small droplets can related activities and exposures as not find differences in the prevalence be inhaled.23 Kokkinaki et al.24 showed well as health outcomes in Lahu of renal and liver dysfunction, that pesticide metabolite levels in urine farmers compared to Thai farmers. evaluated as presence increased AST, samples from pesticide sprayers were While poverty and poor health are increased FECa, or decreased GFR higher than in a control group. This often more common in marginalized among participants with reduced indicates a higher pesticide exposure communities, roughly 10% of AChE compared to those with normal risk among sprayers. Contributing participating Thai and Lahu farmers AChE. This indicates that pesticide factors for pesticide exposure from had expenses that exceeded their exposures did not appear to contribute spraying include spraying duration and income, and the majority of farmers to more health impairments. A frequency, smoking, wind direction, in both groups reported good similar result was reported in a study temperature, pesticide type,25 spray health. Despite these similarities, by Aroonvilairat et al.,7 in which the nozzle type,26 spraying equipment differences in blood chemistry were prevalence of health impairment cleaning, and PPE use.27 found between the two groups. In did not differ significantly between Thai farmers, AChE levels were pesticide-exposed and non-exposed Roughly half of Thai and Lahu farmers significantly higher than Lahu farmers, farmers. On the other hand, reduced in this study were assessed to have reflecting differences in pesticide AChE prevalence was significantly minimal use of PPE (i.e., categories exposure levels. Two measures of higher (adjusted OR of 8.55, Table 4) PPE 0 or PPE 1). Personal protective kidney function, FECa and GFR, were in pesticide spraying farmers compare equipment use in this population, significantly different between the to non-spraying farmers, showing that and particularly among farmers in Thai and Lahu farmers. Age may be AChE reflected pesticide exposure the remote Lahu community, may one explanation for this finding, given more than health impairment. be limited due to factors such as the significantly higher mean age of discomfort, weight, and restriction of the Thai farmers, therefore logistic Farmers can be exposed to pesticides movement,28 in addition to potentially regression models were used to adjust via inhalation, skin absorption, reduced access to PPE due to lack of

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availability or inability to afford, which have previously been documented and language.33 Informal discussions inability to afford payment for as barriers to use by Satya et al.29 with these information sources medical bills, the mild severity of Figure 3 shows common pesticide could occur during routine farm most poisoning cases, anticipated spraying behavior among both Thai activities or community recreational difficulty in diagnosis and treatment, and Lahu farmers, which include lack activities. The consistency and distance to nearest health care facility of chemical resistant gloves and use accuracy of knowledge transferred or poor access to health service; and of a surgical mask with a cloth cover to farmers by pesticide retailers and lack of appropriate medical treatment Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 as PPE. This type of face covering other farmers may not be sufficient to options. In Thailand, universal health is not recommended for handling ensure adoption of proper practices; care provides coverage for pesticide pesticides,30 and is not proper nevertheless, this does represent a poisoning treatment and pesticide respiratory protection for pesticide useful means of farmer education. exposure screening, but accessibility application. Additionally, rather of health services is critical issue for than relying on PPE for protection, Community health volunteers may remote communities such as the Lahu the hierarchy of controls dictates represent a reliable mechanism for farming community assessed in the that engineering and administrative communicating pesticide safety present work. A sensitive, simple, and controls should be implemented information to informal farmers. easily administered and evaluated to reduce pesticide exposure. Such In Thailand, health volunteers are biomarker to examine early exposures controls might include substitution villagers who are paid by the Thai and health risks could help resolve this with less toxic pesticides, improved government to promote public health situation. designs for the control of spray in the community.34 Since these direction and timing, and worker volunteers come from local villages, AChE represents a suitable biomarker training. they understand the culture and to screen pesticide exposure, perhaps lifestyle of people in those villages. through the use of mobile clinics The present study found no The volunteers work with the local during the agricultural season. The relationship between formal education, hospital to perform community health biomarker only indicates exposure Thai language skills, and literacy and monitoring for vital health issues to organophosphate and carbamate reduced levels of AChE. Okoffoet and provide basic treatments. They insecticides, but can nevertheless al.31 suggested that the lower level have a reputation in Thailand as an provide very useful information of education of these farmers may accurate and practical source of health to farmers, particularly given the affect their work behaviors and information. If safe pesticide farming prevalence of these pesticides in subsequent health status.31 However, practices and information could be Thailand. The benefits of AChE Mattah et al.32 suggested that formal introduced to health volunteers, they include a short processing time and education may not impact farmer could then serve as a key resource cost effective method of assessing work practices and exposures to famers, and provide on-the-job pesticide exposure. Widespread use differently than informal training.32 training, work practice observation, of this biomarker in Thai and hill Such informal training could include and farmer education. tribe farming communities could discussions with pesticide retailers, identify cases of early, mild pesticide other farmers, community leaders Any efforts to promote pesticide intoxication and guide both prevention with knowledge regarding farming safety among farmers must consider and treatment of more severe techniques,29 and pesticide packaging economic factors. Farmers often focus intoxication. and marketing materials. Based on the on income more than health due to experience of the research team, the the need to financially support their Limitations latter contained information that was families. Health outcomes caused difficult to apply in real farm-working by chronic occupational pesticide Language barriers were a major scenarios. Retailers and other farmers exposure develop slowly over time, limitation of the present study; therefore represent key sources making them a lower priority than interviews took longer to conduct of information regarding the safe immediate economic needs. Lekei among Lahu farmers compared to application of pesticides by farmers. et al.33 mentioned that farmers Thai farmers. This could introduce Such individuals may practice farming experiencing pesticide poisoning differences in response accuracy using similar practices, come from the may not seek medical treatment between the two groups for questions same community, and share culture for a number of reasons, including regarding PPE use, overall health,

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perceptions of harm and neurological after spraying activities, which would 4. Kongtip P, Nankongnab N, Mahaboonpeeti symptoms. We were not able to allow for greater precision in assessing R, Bootsikeaw S, Batsungnoen K, Hanchenlaksh compare AChE levels before and after the association between exposures and C, Tipayamongkholgul M, Woskie S. Differences the spraying season; that approach health outcomes. among Thai Agricultural Workers’ Health, Working would have allowed us to assess Conditions, and Pesticide Use by Farm Type. Annals the impact of spraying on pesticide Acknowledgments of Work Exposures and Health. 2018;62(2):167-181. accumulation in farmers. Additionally, We would like to express our 5. Kapeleka JA, Sauli E, Sadik O, Ndakidemi PA. more details on spraying activities gratitude to the local hospital staff Biomonitoring of Acetylcholinesterase (AChE) Downloaded from http://meridian.allenpress.com/jhp/article-pdf/11/31/210908/2888347/i2156-9614-11-31-210908.pdf by guest on 24 September 2021 would have been useful, including in the surveyed communities for Activity among Smallholder Horticultural Farmers frequency and duration of spraying, their support. A special thanks go to Occupationally Exposed to Mixtures of Pesticides spraying nozzle type, spray timing, Mr.Wiroon Kuipiapum for his kind in Tanzania. Journal of Environmental and Public and spraying tool maintenance and Lahu community collaboration and health. 2019. https://doi.org/10.1155/2019/3084501 cleaning methods. Mrs.Rungtiwa Na Lampang for her 6. Gesesew HA, Woldemichael K, Massa D, support with the blood and urine Mwanri L. Farmers Knowledge, Attitudes, Practices Conclusions sample collection. We would also and Health Problems Associated with Pesticide Use like to extend special thanks to our in Rural Irrigation Villages, Southwest Ethiopia. The Lahu farmers in the present study subjects who kindly participated in the Spanoghe P, ed. PLoS One. 2016;11(9):e0162527. were informal workers with limited project. This study was funded by Mae https://doi.org/10.1371/journal.pone.0162527 access to public and occupational Fah Luang University. 7. Aroonvilairat S, Kespichayawattana W, health services and experienced Sornprachum T, Chaisuriya P, Siwadune T, pesticide exposures. This study Copyright Policy Ratanabanangkoon K. Effect of Pesticide highlights the utility of mixed-method This is an Open Access article Exposure on Immunological, Hematological and evaluation of pesticide-related farming distributed in accordance with Biochemical Parameters in Thai Orchid Farmers— activities, exposures, and health Creative Commons Attribution A Cross-Sectional Study. International Journal impacts, and the results can help License (http://creativecommons.org/ of Environmental Research and Public Health. guide practical recommendations for licenses/by/3.0/). 2015;12(6):5846-5861. https://doi.org/10.3390/ pesticide exposure reduction. Our ijerph120605846 results suggest that training is needed 8. Singkorn O, Apidechkul T, Putsa B, Detpetukyon to support safe pesticide practices. S, Sunsern R, Thutsanti P, Tamornppark R, Upala Such training could be implemented P, Inta C. Factor associated with alcohol use among at the beginning of the planting season Lahu and Akha hill tribe youths, northern Thailand. through community health volunteers, Subst Abuse Treat Pr. 2019;14(1):5. https://doi. who can effectively communicate this org/10.1186/s13011-019-0193-6 information to Lahu farmers in their References 9. Apidechkul T. Prevalence of thalassemia carriers native language. Any training should among the Lahu hill tribe population, Chiang Rai, be complemented by health services 1. Hongsibsong S, Sittitoon N, Sapbamrer R. Thailand. Asian Biomed. 2017;9(4):527-533. https:// to monitor pesticide exposures and Association of health symptoms with low-level sciendo.com/article/10.5372/1905-7415.0904.423 promote healthy lifestyles. The exposure to organophosphates, DNA damage, AChE 10. Walker AR. Lahu Nyi (Red Lahu) Village Temples research should be expanded to activity, and occupational knowledge and practice and their Buddhist Affiliations 1. Journal of the Siam include other countries in Southeast among rice, corn, and double-crop farmers. J Occup Society. 2006;94:111-145. Asia that have hill tribe communities Health. 2017;59(2):165-176. https://doi.org/10.1539/ 11. Lay AM, Saunders R, Lifshen M, Breslin C, to evaluate the degree to which joh.16-0107-OA LaMontagne A, Tompa E, Smith P. Individual, pesticide exposure risks differ by 2. 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11 Journal of Health & Pollution Vol. 11, No. 31 — September 2021 Nambunmee et al Research Pesticide Spraying and Reduced Cholinesterase Activity

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