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BACKGROUND: Herbicides are the most used class of pesticides worldwide, and insect repellents are widely used globally. Yet, there is a dearth of studies characterizing the associations between these chemical groups and human neurobehavior. Experimental studies suggest that glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides can affect neurobehavior and the cholinergic and glutamatergic pathways in the brain. We aim to assess whether herbicides and insect repellents are associated with neurobehavioral performance in adolescents. METHODS: We assessed 519 participants (11-17 years of age) living in agricultural communities in Ecuador. We quantified urinary concentrations of glyphosate, 2,4-D, and two N,N-diethyl-meta-toluamide (DEET) insect repellent metabolites [3-(diethylcarbamoyl)benzoic acid (DCBA) and 3-(ethylcarbamoyl) benzoic acid (ECBA)] using isotope-dilution mass spectrometry. We assessed neurobehavioral performance using 9 subtests across 5 domains (attention/inhibitory control, memory/learning, language, visuospatial processing, and social perception). We characterized the associations using generalized estimating equations and multiple imputation for metabolites below detection limits. Models were adjusted for demographic and anthropometric characteristics, urinary creatinine, and sexual maturation. Mediation by salivary cortisol, dehydroepiandrosterone, 17β-estradiol, and testosterone was assessed using structural equation modeling. RESULTS: The mean of each neurobehavioral domain score was between 7.0 and 8.7 [standard deviation (SD) range: 2.0-2.3]. Glyphosate was detected in 98.3% of participants, 2,4-D in 66.2%, DCBA in 63.3%, and ECBA in 33.4%. 2,4-D was negatively associated with all neurobehavioral domains, but statistically significant associations were observed with attention/inhibition [score difference per 50% higher metabolite concentration (β)= -0.19 95% confidence interval (CI): -0.31, -0.07], language [β= -0.12 (95% CI: -0.23, -0.01)], and memory/learning [β= -0.11 (95% CI: -0.22, 0.01)]. Glyphosate had a statistically significant negative association only with social perception [β= -0.08 (95% CI: -0.14, -0.01)]. DEET metabolites were not associated with neurobehavioral performance. Mediation by gender and adrenal hormones was not observed. CONCLUSION: This study describes worse neurobehavioral performance associated with herbicide exposures in adolescents, particularly with 2,4-D. Replication of these findings among other pediatric and adult populations is needed. [ABSTRACT FROM AUTHOR]

Background: The cholinergic system has an important role in mood regulation. Cholinesterase inhibitor pesticides (e.g. organophosphates) appear to increase depression and anxiety symptoms in the few existing animal and human studies. Human studies have not described such associations using biomarkers of exposure and studies among children are needed.Methods: We studied 529 adolescents (ages 11-17y) in agricultural communities in the Ecuadorian Andes (ESPINA study). Acetylcholinesterase (AChE) activity was measured in a finger-stick sample. Anxiety and depression symptoms were assessed using the CDI-2 and MASC-2 (greater scores reflect greater internalizing symptoms). Models adjusted for age, gender, hemoglobin, income among others.Results: The median age was 14.38y and 51% were female. The mean (SD) of the following parameters were: AChE 3.7 U/mL (0.55), depression T-score 53.0 (9.4) and anxiety T-score: 57.6 (9.8). Lower AChE activity (reflecting greater cholinesterase inhibitor exposure) was associated with higher depression symptoms (difference per SD decrease of AChE [β [95% CI:]]: 1.09 [0.02, 2.16]), was stronger among girls (β = 1.61) than boys (β = 0.69), and among younger (<14.38y, β = 1.61) vs. older children (β = 0.57). The associations were strongest among girls <14.38y (β = 3.30 [0.54, 6.05], OR for elevated symptoms per SD decrease in AChE = 2.58 [1.26, 5.27]). No associations were observed with anxiety scores. Analyses of AChE change between 2008 and 2016 concurred with these findings.Discussion: We observed associations between a biomarker of pesticide exposure and children's depression symptoms. Lower AChE activity may create risk for depression in teenagers, particularly among girls during early adolescence. [ABSTRACT FROM AUTHOR]

Agricultural pesticide spray periods increase the pesticide exposure potential of children living nearby and growing evidence indicates that they may affect children's health. We examined the association of time following a heightened agricultural production period, the Mother's Day flower harvest (May), with children's blood pressure (BP). We included cross-sectional information of 313 children ages 4–9 years in Ecuadorian agricultural communities (the ESPINA study). Examinations occurred during a period of low flower production, but within 63–100 days (mean = 81.5, SD = 10.9) following the Mother's Day harvest. BP was measured twice using a pediatric sphygmomanometer and BP percentiles appropriate for age, gender and height were calculated. Participants were 51% male, 1.6% hypertensive and 7.7% had elevated BP. The mean (SD) BP percentiles were: systolic: 51.7 (23.9); diastolic: 33.3 (20.3). There was an inverse relationship between of time after the spray season with percentiles of systolic (difference [β] per 10.9 days after the harvest: −4.3 [95%CI: −6.9, −1.7]) and diastolic BP (β: −7.5 [-9.6, −5.4]) after adjusting for race, heart rate and BMI-for-age z-score. A curvilinear association with diastolic BP was observed. For every 10.9 days that a child was examined sooner after the harvest, the OR of elevated BP/hypertension doubled (OR: 2.0, 95% CI: 1.3, 3.1). Time after the harvest was positively associated with acetylcholinesterase. Children examined sooner after a heightened pesticide spray period had higher blood pressure and pesticide exposure markers than children examined later. Further studies with multiple exposure-outcome measures across pesticide spray periods are needed. • We assessed blood pressure (BP) in children examined after a pesticide spray period. • BP was higher in children examined sooner (vs later) after the pesticide spray period. • Elevated odds of hypertension/prehypertension were present in those examined sooner. • Time after the spray season was positively associated with acetylcholinesterase. [ABSTRACT FROM AUTHOR]

Background: Pesticide drift from agricultural plantations increases the chemical exposure potential of people living nearby. Some studies have described positive associations between pesticide exposures and blood pressure (BP) in adults, whereas limited evidence in children suggests negative associations. This study characterized the association between home proximity to plantations and BP among children living in a flower-growing county in Ecuador.Methods: We included 310 4-9-year-old children living in Pedro Moncayo County, Ecuador as part of The ESPINA study. We calculated age, gender and height-specific BP z-scores. Geographic coordinates of homes and flower plantations were collected using GPS receivers and satellite imagery. Exposure-outcome associations were analyzed using linear regression.Results: The mean home distance to the nearest flower plantation was 449 m (SD: 347) and the median plantation area within 150 m of participants' homes was 989 m2 (25th-75Th percentile: 492-3164) among those with non-zero values. Children living closer to plantations had lower AChE activity. Systolic BP z-score increased with greater residential proximity to plantations (0.24 SD per 1000 m [95% CI: 0.01, 0.47]) and with greater areas of flower plantations within 150 m of homes (0.03 SD per 1000 m2 [0.00, 0.06]), after adjusting for socio-economic, anthropometric and other factors. Further adjustment for acetylcholinesterase and hemoglobin strengthened these associations.Conclusions: Proximity of homes to flower plantations and greater plantation areas within 150 m from homes were associated with higher systolic BP, independent of cholinesterase activity. This suggests that non-cholinesterase inhibitor pesticide drift from agricultural plantations may be sufficient to induce physiologic changes on children living nearby. [ABSTRACT FROM AUTHOR]

Purpose: Mother’s Day (May) is a holiday with substantial demand for flowers, associated with heightened flower production and escalated pesticide use. The effect of spray seasons on pesticide exposures of children living in agricultural communities but who do not work in agriculture is poorly understood. In this study, we estimated the association of time after Mother’s Day harvest with children’s acetylcholinesterase (AChE) activity. AChE is a physiological marker of organophosphate/carbamate pesticide exposures that may take up to 3 months to normalize after its inhibition.Methods: We examined 308 children, aged 4–9 years, in Ecuadorian agricultural communities during a low flower-production season but within 63–100 days (mean: 81.5 days, SD: 10.9) after Mother’s Day harvest. We quantified AChE activity (mean: 3.14 U/mL, SD: 0.49) from a single finger-stick sample.Results: We observed positive linear associations between time after the harvest and AChE among participants living near plantations. The associations were strongest among participants living within 233 m [(0.15 U/mL (95% CI 0.02, 0.28)], slightly weaker among participants living within 234–532 m [0.11 U/mL (0.00, 0.23)], and not associated among participants at greater distances. Similar findings were observed across categories of areas of flower plantations within 500 m of homes.Conclusions: These cross-sectional findings suggest that a peak pesticide-use period can decrease AChE activity of children living near plantations. These seasonal pesticide exposures could induce short- and long-term developmental alterations in children. Studies assessing exposures at multiple times in relation to pesticide spray seasons among children who do not work in agriculture are needed. [ABSTRACT FROM AUTHOR]

Background Exposures to cholinesterase inhibitor pesticides (e.g. organophosphates) have been associated with children’s neurobehavioral alterations, including attention deficit and impulsivity. Animal studies have observed transient alterations in neurobehavioral performance in relation to cholinesterase inhibitor pesticide exposures; however, limited evidence exists regarding transient effects in humans. Methods We estimated the associations between neurobehavioral performance and time after Mother’s Day flower harvest (the end of a heightened pesticide usage period) among 308 4-to 9-year-old children living in floricultural communities in Ecuador in 2008 who participated in the ESPINA study. Children’s neurobehavior was examined once (NEPSY-II: 11 subtests covering 5 domains), between 63 and 100 days (SD: 10.8 days) after Mother’s Day harvest (blood acetylcholinesterase activity levels can take 82 days to normalize after irreversible inhibition with organophosphates). Results The mean (SD) neurobehavioral scaled scores across domains ranged from 6.6 (2.4) to 9.9 (3.3); higher values reflect greater performance. Children examined sooner after Mother’s Day had lower neurobehavioral scores than children examined later, in the domains of (score difference per 10.8 days, 95%CI): Attention/Inhibitory Control (0.38, 0.10–0.65), Visuospatial Processing (0.60, 0.25–0.95) and Sensorimotor (0.43, 0.10–0.77). Scores were higher with longer time post-harvest among girls (vs. boys) in Attention/Inhibitory Control. Conclusions Our findings, although cross-sectional, are among the first in non-worker children to suggest that a peak pesticide use period may transiently affect neurobehavioral performance, as children examined sooner after the flower harvest had lower neurobehavioral performance than children examined later. Studies assessing pre- and post-exposure measures are needed. [ABSTRACT FROM AUTHOR]

Background: Acetylcholinesterase (AChE) inhibitors are commonly used pesticides that can effect hemodynamic changes through increased cholinergic stimulation. Children of agricultural workers are likely to have paraoccupational exposures to pesticides, but the potential physiological impact of such exposures is unclear.Objectives: We investigated whether secondary pesticide exposures were associated with blood pressure and heart rate among children living in agricultural Ecuadorian communities.Methods: This cross-sectional study included 271 children 4-9 years of age [51% cohabited with one or more flower plantation workers (mean duration, 5.2 years)]. Erythrocyte AChE activity was measured using the EQM Test-mate system. Linear regression models were used to estimate associations of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate with AChE activity, living with flower workers, duration of cohabitation with a flower worker, number of flower workers in the child's home, and number of practices that might increase children's exposure to pesticides.Results: Mean (± SD) AChE activity was 3.14 ± 0.49 U/mL. A 1-U/mL decrease in AChE activ­ity was associated with a 2.86-mmHg decrease in SBP (95% CI: -5.20, -0.53) and a 2.89-mmHg decrease in DBP (95% CI: -5.00, -0.78), after adjustment for potential confounders. Children liv­ing with flower workers had lower SBP (-1.72 mmHg; 95% CI: -3.53, 0.08) than other children, and practices that might increase exposure also were associated with lower SBP. No significant asso­ciations were found between exposures and heart rate.Conclusions: Our findings suggest that subclinical secondary exposures to pesticides may affect vascular reactivity in children. Additional research is needed to confirm these findings. [ABSTRACT FROM AUTHOR]

Off-target drift of pesticides from farms increases the risk of pesticide exposure of people living nearby. Cholinesterase inhibitors (i.e. organophosphates and carbamates) are frequently used in agriculture and inhibit acetylcholinesterase (AChE) activity. Greenhouse agriculture is an important production method, but it is unknown how far pesticide drift from greenhouses can extend and expose people living nearby. This study included 1156 observations from 3 exams (2008, Apr, 2016 and Jul–Oct 2016) of 623 children aged 4-to-17 years living in agricultural communities in Ecuador. AChE, a physiological marker of cholinesterase inhibitor exposure, was measured in blood. Geographic positioning of greenhouses and homes were obtained using GPS receivers and satellite imagery. Distances between homes and the nearest greenhouse edge, and areas of greenhouse crops within various buffer zones around homes were calculated. Repeated-measures regression adjusted for hemoglobin and other covariates estimated change in AChE relative to distance from greenhouses. The pooled mean (SD) of AChE activity was 3.58 U/mL (0.60). The median (25th-75th %tile) residential distance to crops was 334 m (123, 648) and crop area within 500 m of homes (non-zero values only) was 18,482 m2 (7115, 61,841). Residential proximity to greenhouse crops was associated with lower AChE activity among children living within 275 m of crops (AChE difference per 100 m of proximity [95% CI] = −0.10 U/mL [-0.20, −0.006]). Lower AChE activity was associated with greater crop area within 500 m of homes (AChE difference per 1000 m2 [95% CI] = −0.026 U/mL [-0.040, −0.012]) and especially within 150 m (−0.037 U/mL [-0.065, −0.007]). Residential proximity to floricultural greenhouses, especially within 275 m, was associated with lower AChE activity among children, reflecting greater cholinesterase inhibitor exposure from pesticide drift. Analyses of residential proximity and crop areas near homes yielded complementary findings. Mitigation of off-target drift of pesticides from crops onto nearby homes is recommended. • Off-target drift of pesticides from greenhouses may reach people living nearby. • Cholinesterase inhibitor pesticides inhibit acetylcholinesterase (AChE) activity. • We examined 623 children (3 exams: 1156 observations) living near agriculture. • Home proximity to crops (within 275 m) was associated with lower child AChE activity. • Greater crop areas within 500 m (especially <150 m) of homes associated with lower AChE. [ABSTRACT FROM AUTHOR]

Background Adrenal and sex hormone dysregulation have been independently associated with increased depression and anxiety. Cortisol can modify production of sex hormones and hormone-mood associations. This study evaluated associations and interplay of sex and adrenal hormones with depression and anxiety. Methods We assessed 545 Ecuadorian adolescents (11-17y, 50.4% female, ESPINA) for depression and anxiety symptoms using standardized scales. Testosterone, cortisol, dehydroepiandrosterone (DHEA), and estradiol (boys only) were measured in saliva. We performed logistic regression modeling to calculate odds ratios (OR) of elevated depression or anxiety (scores ≥60) comparing participants with low (<10th percentile) and elevated hormones (≥90th percentile) to normal concentrations (10th-90th percentile). Effect modification by cortisol and testosterone was assessed. Models adjusted for demographic, anthropometric, and circadian measures. Results In all participants, elevated testosterone (OR [95%CI:]=1.78 [0.98, 3.23]) and cortisol (OR=1.69 [0.95, 2.99]) were marginally associated with elevated anxiety scores. In boys, elevated estradiol was associated with elevated depression (OR=4.75 [1.95, 11.56]) and anxiety scores (OR=2.43 [1.01, 5.84]). In linear regression, estradiol was positively associated with depression (difference/10% hormone increase (β=0.45 [0.15, 0.75]) and anxiety scores (β=0.42 [0.13, 0.72]). Higher cortisol levels strengthened the depression association with estradiol in boys (β=0.54 [0.12, 0.96]), and with testosterone (β= -0.19 [-0.35, -0.03]) and DHEA (β= -0.12 [-0.22, -0.02]) in girls. Testosterone also modified associations. Limitations This was a cross-sectional analysis. Discussion Elevated testosterone, cortisol, and estradiol (≥90th percentile) were associated with altered mood. Cortisol and testosterone were considerable effect modifiers to the associations of most hormones with depression and anxiety. [ABSTRACT FROM AUTHOR]

Background: Children living near greenhouse agriculture may have an increased risk of pesticide exposure due to drift or direct contact with pesticide-treated areas. However, little is known about whether this increased potential for chronic exposure may impair their neurodevelopment.Methods: We examined 307 children aged 4-9 years, living in agricultural communities in Ecuador (ESPINA study). The two exposures calculated were residential distance from the nearest flower plantation perimeter and flower plantation surface area within 100 m of homes. Five neurobehavioral domains were assessed: Attention/Inhibitory Control, Memory/Learning, Visuospatial processing and Sensorimotor (higher values reflect better performance). Low scores were defined according to the test's cut-offs. Models were adjusted for demographic, socio-economic and growth variables.Results: The mean (SD) residential distance to the nearest flower plantation was 446 m (344). Living 100 m closer to crops was associated with increased odds (OR [95% CI]) of low scores in the domains of Memory/Learning (1.24 [1.05, 1.46]) and Language (1.09 [1.00, 1.19]). Associations were strongest among children living within 50 m, having significantly lower scores in Language (-1.28 which is ~50% of a SD [-2.50, -0.06]), Attention/Inhibitory Control (-1.24 units, [-2.45, -0.04]), and Memory/Learning (-0.91, [-1.99, 0.17]), compared to children living farther than 500 m. Analyses of areas of flower crops near homes concurred with these findings.Conclusions: Close residential proximity to greenhouse floricultural crops was associated with adverse neurobehavioral performance in Attention/Inhibitory Control, Language and Memory/Learning among children. This highlights the importance of reducing pesticide drift from plantations to nearby homes. [ABSTRACT FROM AUTHOR]

Organophosphates are insecticides that inhibit the enzymatic activity of acetylcholinesterase (AChE). Because of this, AChE is considered a physiological marker of organophosphate exposure in agricultural settings. However, limited research exists on the associations between urinary organophosphate metabolites and AChE activity in children. This study included 526 participants from 2 exams (April and July–October 2016) of ages 12–17 years living in agricultural communities in Ecuador. AChE activity was measured at both examinations, and organophosphate metabolites, including para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPy), and malathion dicarboxylic acid (MDA) were measured in urine collected in July–October. We used generalized estimating equation generalized linear model (GEEGLM), adjusting for hemoglobin, creatinine, and other demographic and anthropometric covariates, to estimate associations of urinary metabolite concentrations with AChE activity (July–October) and AChE% change between April and July–October. The mean (SD) of AChE and AChE% change (April vs July–October) were 3.67 U/mL (0.54) and −2.5% (15.4%), respectively. AChE activity was inversely associated with PNP concentration, whereas AChE% change was inversely associated with PNP and MDA. There was evidence of a threshold: difference was only significant above the 80th percentile of PNP concentration (AChE difference per SD increase of metabolite = −0.12 U/mL [95%CI: 0.20, −0.04]). Likewise, associations with AChE% change were significant only above the 80th percentile of TCPy (AChE % change per SD increase of metabolite = −1.38% [95%CI: 2.43%, −0.32%]) and PNP -2.47% [95%CI: 4.45%, −0.50%]). PNP concentration at ≥80th percentile was associated with elevated ORs for low AChE activity of 2.9 (95% CI: 1.5, 5.7) and for AChE inhibition of ≤ -10% of 3.7 (95% CI: 1.4, 9.8). Urinary organophosphate metabolites, including PNP, TCPy and MDA, particularly at concentrations above the 80th percentile, were associated with lower AChE activity among adolescents. These findings bring attention to the value of using multiple constructs of pesticide exposure in epidemiologic studies. [Display omitted] • Organophosphate (OP) pesticides inhibit acetylcholinesterase (AChE) activity. •Unclear associations between OP metabolites and AChE have been described previously. •We measured urinary OP metabolites in 526 adolescents living in agricultural areas. •OP metabolites including PNP, TCPy and MDA were inversely associated with AChE. •Associations were strongest at concentrations above the 80th percentile. [ABSTRACT FROM AUTHOR]

Background: Organophosphates are frequently applied insecticides that inhibit acetylcholinesterase (AChE) activity resulting in cholinergic overstimulation. Limited evidence suggests that organophosphates may alter thyroid hormone levels, although studies have yielded inconsistent findings. We aimed to test the associations between AChE activity, a physiological marker of organophosphate exposure, and thyroid function in adolescents.Methods: We included information of 80 adolescent participants (ages 12-17y in 2016, 53% male) growing up in agricultural settings in Ecuador. We measured fingerstick erythrocytic AChE activity and hemoglobin concentration, and concurrent serum thyroid stimulating hormone (TSH) and free-T4 (fT4) concentrations. General linear models were used to test associations which adjusted for demographic and anthropometric variables. TSH associations were further adjusted for fT4.Results: The mean (SD) AChE, TSH and fT4 levels were 3.77 U/mL (0.55), 2.82 μIU/ml (1.49) and 1.11 ng/dl (0.13), respectively. Lower AChE activity, indicating greater organophosphate exposure, was marginally associated with greater fT4 concentrations (difference per SD decrease in AChE activity (β) = 0.03 ng/dL, [90% CI: 0.00, 0.06]) but not with TSH (β = -0.01 μIU/ml, [-0.38, 0.36]). Gender modified the AChE-TSH association (p = 0.03). In girls, lower AChE activity was associated with higher fT4 levels (β=0.05 ng/dL [0.01, 0.10]) and lower TSH concentrations (β = -0.51 μIU/ml, [-1.00, -0.023]). No associations were observed in boys.Discussion: These cross-sectional findings suggest that alterations in the cholinergic system from organophosphate exposures can increase fT4 levels coupled with a beyond-compensatory downregulation of TSH in female adolescents. This is the first study to characterize these associations in adolescents. [ABSTRACT FROM AUTHOR]

Background: Organophosphate, pyrethroid, and neonicotinoid insecticides have resulted in adrenal and gonadal hormone disruption in animal and in vitro studies; limited epidemiologic evidence exists in humans. We assessed relationships of urinary insecticide metabolite concentrations with adrenal and gonadal hormones in adolescents living in Ecuadorean agricultural communities., Methods: In 2016, we examined 522 Ecuadorian adolescents (11-17y, 50.7% female, 22% Indigenous; ESPINA study). We measured urinary insecticide metabolites, blood acetylcholinesterase activity (AChE), and salivary testosterone, dehydroepiandrosterone (DHEA), 17β-estradiol, and cortisol. We used general linear models to assess linear (β = % hormone difference per 50% increase of metabolite concentration) and curvilinear relationships (β 2  = hormone difference per unit increase in squared ln-metabolite) between ln-metabolite or AChE and ln-hormone concentrations, stratified by sex, adjusting for anthropometric, demographic, and awakening response variables. Bayesian Kernel Machine Regression was used to assess non-linear associations and interactions., Results: The organophosphate metabolite malathion dicarboxylic acid (MDA) had positive associations with testosterone (β boys  = 5.88% [1.21%, 10.78%], β girls  = 4.10% [-0.02%, 8.39%]), and cortisol (β boys  = 6.06 [-0.23%, 12.75%]. Para-nitrophenol (organophosphate) had negatively-trending curvilinear associations, with testosterone (β 2 boys  = -0.17 (-0.33, -0.003), p = 0.04) and DHEA (β 2 boys  = -0.49 (-0.80, -0.19), p = 0.001) in boys. The neonicotinoid summary score (β boys  = 5.60% [0.14%, 11.36%]) and the neonicotinoid acetamiprid-N-desmethyl (β boys  = 3.90% [1.28%, 6.58%]) were positively associated with 17β-estradiol, measured in boys only. No associations between the pyrethroid 3-phenoxybenzoic acid and hormones were observed. In girls, bivariate response associations identified interactions of MDA, Para-nitrophenol, and 3,5,6-trichloro-2-pyridinol (organophosphates) with testosterone and DHEA concentrations. In boys, we observed an interaction of MDA and Para-nitrophenol with DHEA. No associations were identified for AChE., Conclusions: We observed evidence of endocrine disruption for specific organophosphate and neonicotinoid metabolite exposures in adolescents. Urinary organophosphate metabolites were associated with testosterone and DHEA concentrations, with stronger associations in boys than girls. Urinary neonicotinoids were positively associated with 17β-estradiol. Longitudinal repeat-measures analyses would be beneficial for causal inference., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Background: Organophosphate exposures can affect children's neurodevelopment, possibly due to neurotoxicity induced by acetylcholinesterase (AChE) inhibition, and may affect boys more than girls. We tested the hypothesis that lower AChE activity is associated with lower neurobehavioral development among children living in Ecuadorian floricultural communities., Methods: In 2008, we examined 307 children (age: 4-9 years; 52% male) and quantified AChE activity and neurodevelopment in 5 domains: attention/executive functioning, language, memory/learning, visuospatial processing, and sensorimotor (NEPSY-II test). Associations were adjusted for demographic and socioeconomic characteristics and height-for-age, flower worker cohabitation, and hemoglobin concentration., Results: Mean ± standard deviation AChE activity was 3.14 ± 0.49 U/mL (similar for both genders). The range of scores among neurodevelopment subtests was 5.9 to 10.7 U (standard deviation: 2.6-4.9 U). Girls had a greater mean attention/executive functioning domain score than boys. In boys only, there were increased odds ratios of low (<9th percentile) neurodevelopment among those in the lowest tertile versus the highest tertile of AChE activity (odds ratios: total neurodevelopment: 5.14 [95% confidence interval (CI): 0.84 to 31.48]; attention/executive functioning domain: 4.55 [95% CI: 1.19 to 17.38], memory/learning domain: 6.03 [95% CI: 1.17 to 31.05]) after adjustment for socioeconomic and demographic factors, height-for-age, and hemoglobin. Within these domains, attention, inhibition and long-term memory subtests were most affected., Conclusions: Low AChE activity was associated with deficits in neurodevelopment, particularly in attention, inhibition, and memory in boys but not in girls. These critical cognitive skills affect learning and academic performance. Added precautions regarding secondary occupational pesticide exposure would be prudent.

Background: Children of workers exposed to pesticides are at risk of secondary pesticide exposure. We evaluated the potential for lower acetylcholinesterase activity in children cohabiting with fresh-cut flower plantation workers, which would be expected from organophosphate and carbamate insecticide exposure. Parental home surveys were performed and acetylcholinesterase activity was measured in 277 children aged 4-9 years in the Secondary Exposure to Pesticides among Infants, Children and Adolescents (ESPINA) study. Participants lived in a rural county in Ecuador with substantial flower plantation activity., Results: Mean acetylcholinesterase activity was 3.14 U/ml, standard deviation (SD) of 0.49. It was lower by 0.09 U/ml (95% confidence interval (CI) -0.19, -0.001) in children of flower workers (57% of participants) than non-flower workers' children, after adjustment for gender, age, height-for-age, hemoglobin concentration, income, pesticide use within household lot, pesticide use by contiguous neighbors, examination date and residence distance to nearest flower plantation. Using a 4 level polychotomous acetylcholinesterase activity dependent variable, flower worker cohabitation (vs. not) had odds ratio 3.39 (95% CI 1.19, 9.64) for being <15th percentile compared to the highest tertile. Children cohabitating for ≥5 years (vs. never) had OR of 4.11 (95% CI: 1.17, 14.38) of AChE activity within <15th percentile compared to the highest tertile., Conclusions: Cohabitation with a flower worker was related to lower acetylcholinesterase activity in children. This supports the hypothesis that the amount of take-home pesticides from flower workers suffices to decrease acetylcholinesterase activity, with lower activity associated with longer exposure., (Copyright © 2012 Elsevier Inc. All rights reserved.)