Repeated pesticide exposure among North Carolina migrant and seasonal farmworkers

Comparing Longitudinal Measures of Cholinesterase as Biomarkers for Insecticide Exposure Among Latinx Children in Rural Farmworker and Urban Nonfarmworker Communities in North Carolina

OBJECTIVE

In a 2-group prospective design, this study compared seasonal cholinesterase levels of Latinx children in rural farmworker families and comparable urban children to assess the impact of environmental exposure to cholinesterase-inhibiting insecticides.

METHODS

Quarterly blood samples and passive dosimeter wristbands were collected over 2 years in 8-year-old children (74 rural, 62 urban). Laboratory analysis assessed total cholinesterase, acetylcholinesterase, and butyrylcholinesterase from blood samples, and insecticides from wristbands.

RESULTS

In spring and summer, total cholinesterase and acetylcholinesterase levels were depressed in rural children compared with winter and fall. Butyrylcholinesterase was depressed in rural children in fall compared with spring and summer. Adjustment for insecticide exposure did not affect these associations.

CONCLUSIONS

Environmental exposures to cholinesterase-inhibiting insecticides have measurable biochemical effects on blood cholinesterases in rural children from farmworker families.

Pesticides and environmental injustice in the USA: root causes, current regulatory reinforcement and a path forward

Many environmental pollutants are known to have disproportionate effects on Black, Indigenous and People of Color (BIPOC) as well as communities of low-income and wealth. The reasons for these disproportionate effects are complex and involve hundreds of years of systematic oppression kept in place through structural racism and classism in the USA. Here we analyze the available literature and existing datasets to determine the extent to which disparities in exposure and harm exist for one of the most widespread pollutants in the world – pesticides. Our objective was to identify and discuss not only the historical injustices that have led to these disparities, but also the current laws, policies and regulatory practices that perpetuate them to this day with the ultimate goal of proposing achievable solutions. Disparities in exposures and harms from pesticides are widespread, impacting BIPOC and low-income communities in both rural and urban settings and occurring throughout the entire lifecycle of the pesticide from production to end-use. These disparities are being perpetuated by current laws and regulations through 1) a pesticide safety double standard, 2) inadequate worker protections, and 3) export of dangerous pesticides to developing countries. Racial, ethnic and income disparities are also maintained through policies and regulatory practices that 4) fail to implement environmental justice Executive Orders, 5) fail to account for unintended pesticide use or provide adequate training and support, 6) fail to effectively monitor and follow-up with vulnerable communities post-approval, and 7) fail to implement essential protections for children. Here we’ve identified federal laws, regulations, policies, and practices that allow for disparities in pesticide exposure and harm to remain entrenched in everyday life for environmental justice communities. This is not simply a pesticides issue, but a broader public health and civil rights issue. The true fix is to shift the USA to a more just system based on the Precautionary Principle to prevent harmful pollution exposure to everyone, regardless of skin tone or income. However, there are actions that can be taken within our existing framework in the short term to make our unjust regulatory system work better for everyone.

Pesticide exposure among Latinx child farmworkers in North Carolina

BACKGROUND

Although pesticides have adverse effects on child health and development, little research has examined pesticide exposure among child farmworkers. This analysis addresses two specific aims: (1) describes pesticide exposure among Latinx child farmworkers in North Carolina, and (2) delineates factors associated with this pesticide exposure.

METHODS

In 2018 (n = 173) and 2019 (n = 156) Latinx child farmworkers completed interviews and wore silicone wristbands for a single day to measure pesticide exposure. Wristbands were analyzed for 70 pesticides.

RESULTS

Most Latinx child farmworkers were exposed to multiple pesticides; the most frequent were pyrethroids (69.9% in 2018, 67.9% in 2019), organochlorines (51.4% in 2018, 55.1% in 2019), and organophosphates (51.4% in 2018, 34.0% in 2019). Children were exposed to a mean of 2.15 pesticide classes in 2018 and 1.91 in 2019, and to a mean of 4.06 pesticides in 2018 and 3.34 in 2019. Younger children (≤15 years) had more detections than older children; children not currently engaged in farm work had more detections than children currently engaged in farm work. Migrant child farmworkers had more detections than nonmigrants. For specific pesticides with at least 20 detections, detections and concentrations were generally greater among children not currently engaged in farm work than children currently engaged.

CONCLUSIONS

Children who live in farmworker communities are exposed to a plethora of pesticides. Although further research is needed to document the extent of pesticide exposure and its health consequences, sufficient information is available to inform the policy needed to eliminate this pesticide exposure in agricultural communities.

Evaluation of occupational pesticide exposure on Egyptian male adolescent cognitive and motor functioning

BACKGROUND

Chronic low-level exposure to organophosphorus pesticides is associated with adverse health effects, including a decline in neurological functioning and long-term impairment. These negative effects may be more detrimental in children and adolescents due to their critical stage in development. Little work has investigated the effects of chronic exposure to pesticides, specifically chlorpyrifos (CPF) during the adolescent period.

OBJECTIVES

To examine effects of CPF exposure over a year-long period within a group of male adolescents in Egypt (N = 242, mean age = 17.36), including both pesticide applicators and non-applicators.

METHODS

Associations between average CPF exposure (measured via urinary metabolite levels of 3,5,6-trichloro-2-pyridinol [TCPy]) and neurobehavioral functioning were examined in a 1-year longitudinal study. Given previous literature, higher levels of TCPy were expected to be associated with worse neurobehavioral functioning.

RESULTS

Using mixed effects linear regression, average TCPy exposure predicted deficits in more complex neurobehavioral tasks (Benton visual retention, digit span reverse, match to sample, serial digit learning, and alternating tapping) with estimates of effects ranging from -0.049 to 0.031. Age (effects ranging from 0.033 to 0.090) and field station (effects ranging from -1.266 to -0.278) were significantly predictive of neurobehavioral functioning over time. An interaction effect was found for field station and TCPy across several neurobehavioral domains.

DISCUSSION

Results show that occupational exposure to pesticides may have particularly deleterious effects on complex neurobehavioral domains. Additionally, differences across field stations and the age at which individuals are exposed may be important factors to investigate in future research.

Genetic Knowledge and Communication Among Mexican Farmworkers and Non-farmworkers in North Carolina

It is important to understand genetics within the context of health. This paper assesses (a) genetic knowledge among Mexican-born farmworker and non-farmworker adults; (b) their interpersonal and device sources of genetic knowledge; and (c) the association between their genetic knowledge and the sources of this genetic knowledge.Interviews were conducted with Mexican-born farmworkers (100) and non-farmworkers (100) in North Carolina. Participants answered 15 questions to assess genetic knowledge, and sources from which they had seen or heard about genes and genetics.Results show limited knowledge of genetics, with farmworkers and non-farmworkers providing a similar level of correct responses (6.6 versus 7.3), but with farmworkers providing more incorrect responses (4.0 versus 2.7). Important sources of genetic information for farmworkers were promotoras (47%), compared to teachers (49%) for non-farmworkers.This study demonstrates a need for increased dissemination of genetic information to Mexican-origin farmworkers and non-farmworkers.

Occupational health and safety in agriculture. A systematic review

Introduction: The prevalence of occupational diseases in the agricultural sector is higher than in other industries, since agricultural workers are at higher risk of exposure to different chemicals and pesticides, and are more prone to occupational accidents.Objective: To conduct a review of recent literature on occupational health and risk in agriculture.Materials and methods: A literature search was conducted in PubMed, SciencieDirect and Scopus using the following search strategy: type of articles: original research papers; language: English; publication period: 2006-2016; search terms: "agricultural health", "agrarian health", "risk factors", "epidemiology", "causality" and "occupational", used in different combinations ("AND" and "OR").Results: The search yielded 350 articles, of which 102 met the inclusion criteria. Moreover, 5 articles were found in grey literature sources and included in the final analysis. Most research on this topic has been conducted in the United States, which produced 91% (97/107) of the articles included.Conclusions: Most studies on health and safety in agriculture focused primarily on the harmful effects of occupational exposure to agrochemicals and pesticides, and the consequences of occupational accidents. However, since more than 90% of these studies come from the United States, a more comprehensive approach to health in agriculture is required, since what is reported here may be far from the reality of other regions, especially Latin America.

Hired Latinx child farm labor in North Carolina: The demand-support-control model applied to a vulnerable worker population

BACKGROUND

US government child labor policies allow children as young as age 10 to be hired as workers on farms not operated by family members. Children may face substantial health risks in an industry known for high worker morbidity and mortality rates, due to high demands for productivity, and low control and little support because of the organization of the workplace. This paper examines how child farmworkers in North Carolina experience their work situation.

METHODS

In-depth interviews conducted in 2016 with 30 Latinx child farmworkers, ages 10 to 17, were analyzed using concepts from the demand-control-support model. All had worked as either migrant or seasonal hired farmworkers within the past year.

RESULTS

Children reported planting, cultivating, and harvesting crops including fruits, vegetables, and tobacco. The crew leader supervisory system, piece-rate pay, and coworker pressure produced significant demands to work quickly and take risks including lifting heavy loads, operating mechanical equipment, and working in excessive heat. Children had little control over work to counter demands they experienced; and they labored in a state of fear of firing, wage theft, and other sanctions. Support was variable, with younger children more likely to experience family and coworker support than older children.

CONCLUSIONS

The high demands with limited control and, for some, little support, that these children experience place them at risk and show the possibility of injury and exploitation. Future research should systematically document the occupational injury and illness of hired child farmworkers, and consider whether changes in labor policy are warranted.

Olfactory Function in Latino Farmworkers Over 2 Years: Longitudinal Exploration of Subclinical Neurological Effects of Pesticide Exposure

OBJECTIVE

We compared patterns of olfactory function over 2 years in pesticide-exposed male Latino farmworkers and male Latino workers in industries without pesticide exposure.

METHODS

At five points over 2 years, workers completed tests of odor threshold (16 concentrations of n-butanol) using a well-established methodology. Tests at two or more time points were completed by 156 farmworkers and 118 non-farmworkers.

RESULTS

Farmworkers required significantly higher odorant concentrations at Contact 1 and across the 2-year follow-up to detect the odor. When adjusted for Contact 1, between-group differences persisted, but odor threshold performance did not worsen over time.

CONCLUSIONS

Pesticide exposure has been linked to neurodegenerative disease, as has declining olfactory function. Persistently poorer olfactory function among pesticide-exposed workers suggests the need to monitor neurological function in this vulnerable worker population.

Farmworker and nonfarmworker Latino immigrant men in North Carolina have high levels of specific pesticide urinary metabolites

This article compares detections and concentrations of specific organophosphate (OP), bis-dithiocarbamate, and pyrethroid pesticide urinary metabolites among Latino male farmworkers and nonfarmworkers in North Carolina. Data are from interviews and urine samples collected in 2012 and 2013. Farmworkers and nonfarmworkers frequently had detections for OP and pyrethroid pesticide urinary metabolites. Detection of bis-dithiocarbamate urinary metabolites was less frequent, but substantial among the nonfarmworkers. The concentrations of organophosphate, bis-dithiocarbamate, and pyrethroid pesticide urinary metabolites were high for farmworkers and nonfarmworkers compared to National Health and Nutrition Examination Survey results. Pesticide urinary metabolite detection was not associated with occupation in nonfarmworkers. Research for reducing pesticide exposure among farmworkers remains important; research is also needed to determine pesticide exposure pathways among Latino nonfarmworkers.

Pesticide Urinary Metabolites Among Latina Farmworkers and Nonfarmworkers in North Carolina

OBJECTIVES

This paper compares detections and concentrations of pesticide urinary metabolites for Latina farmworkers and nonfarmworkers in North Carolina.

METHODS

Thirty-one farmworkers and 55 nonfarmworkers provided urine samples in 2012 and 2013. Urine samples were analyzed for detections and concentrations of organophosphate insecticide, bis-dithiocarbamate fungicide, and pyrethroid insecticide urinary metabolites.

RESULTS

Detections for several organophosphate and pyrethroid pesticide urinary metabolites were present for substantial proportions of the farmworkers and nonfarmworkers. Concentrations for several of these metabolites were high. Farmworkers and nonfarmworkers were similar in detections and concentrations for the pesticide urinary metabolites included in this analysis.

CONCLUSIONS

Participant pesticide exposure increases health risks for them and their children. Research needs to document pesticide exposure, its health effects, and ways to reduce it. Current information justifies policy development to reduce pesticide exposure in all communities.

Diet Quality among Preschool-Age Children of Latino Migrant and Seasonal Farmworkers in the United States

Dietary quality has been linked to obesity in children. Obesity among children of farmworker families exceeds that of other US Hispanic children. Knowledge of their dietary quality is needed to understand the origins and prevention of this obesity. Mothers (n = 237) of 3-year old children in farmworker families completed 3 24-hour recalls with trained interviewers using the Nutrition Data System for Research (NDS-R). Output was used to calculate total and component scores of the Revised Children's Diet Quality Index (RC-DQI). Mean total score was 62 (range 36-86) of an optimal score of 90. Scores for total fat, total grains, excess juice and iron were >80 % of the optimum, but scores for added sugar, whole grains, fruits, and vegetables were considerably lower. Children in farmworker families have low overall dietary quality. Intervention targeted to specific food issues may be an efficient way to addressing the problem.

Critical and systematic evaluation of data for estimating human exposures to 2,4-dichlorophenoxyacetic acid (2,4-D) - quality and generalizability

The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been commercially available since the 1940's. Despite decades of data on 2,4-D in food, air, soil, and water, as well as in humans, the quality the quality of these data has not been comprehensively evaluated. Using selected elements of the Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument (temporal variability, avoidance of sample contamination, analyte stability, and urinary methods of matrix adjustment), the quality of 156 publications of environmental- and biomonitoring-based 2,4-D data was examined. Few publications documented steps were taken to avoid sample contamination. Similarly, most studies did not demonstrate the stability of the analyte from sample collection to analysis. Less than half of the biomonitoring publications reported both creatinine-adjusted and unadjusted urine concentrations. The scope and detail of data needed to assess temporal variability and sources of 2,4-D varied widely across the reviewed studies. Exposures to short-lived chemicals such as 2,4-D are impacted by numerous and changing external factors including application practices and formulations. At a minimum, greater transparency in reporting of quality control measures is needed. Perhaps the greatest challenge for the exposure community is the ability to reach consensus on how to address problems specific to short-lived chemical exposures in observational epidemiology investigations. More extensive conversations are needed to advance our understanding of human exposures and enable interpretation of these data to catch up to analytical capabilities. The problems defined in this review remain exquisitely difficult to address for chemicals like 2,4-D, with short and variable environmental and physiological half-lives and with exposures impacted by numerous and changing external factors.

Personal samplers of bioavailable pesticides integrated with a hair follicle assay of DNA damage to assess environmental exposures and their associated risks in children

Agriculture in the United States employs youth ages ten and older in work environments with high pesticide levels. Younger children in rural areas may also be affected by indirect pesticide exposures. The long-term effects of pesticides on health and development are difficult to assess and poorly understood. Yet, epidemiologic studies suggest associations with cancer as well as cognitive deficits. We report a practical and cost-effective approach to assess environmental pesticide exposures and their biological consequences in children. Our approach combines silicone wristband personal samplers and DNA damage quantification from hair follicles, and was tested as part of a community-based participatory research (CBPR) project involving ten Latino children from farmworker households in North Carolina. Our study documents high acceptance among Latino children and their caregivers of these noninvasive sampling methods. The personal samplers detected organophosphates, organochlorines, and pyrethroids in the majority of the participants (70%, 90%, 80%, respectively). Pesticides were detected in all participant samplers, with an average of 6.2±2.4 detections/participant sampler. DNA damage in epithelial cells from the sheath and bulb of plucked hairs follicles was quantified by immunostaining 53BP1-labled DNA repair foci. This method is sensitive, as shown by dose response analyses to γ radiations where the lowest dose tested (0.1Gy) led to significant increased 53BP1 foci density. Immunolabeling of DNA repair foci has significant advantages over the comet assay in that specific regions of the follicles can be analyzed. In this cohort of child participants, significant association was found between the number of pesticide detections and DNA damage in the papilla region of the hairs. We anticipate that this monitoring approach of bioavailable pesticides and genotoxicity will enhance our knowledge of the biological effects of pesticides to guide education programs and safety policies.

Using "Policy Briefs" to Present Scientific Results of CBPR: Farmworkers in North Carolina

BACKGROUND

Using scientific results to inform policy that improves health and well-being of vulnerable community members is essential to community-based participatory research (CBPR).

OBJECTIVES

We describe "policy briefs," a mechanism developed to apply the results of CBPR projects with migrant and seasonal farmworkers to policy changes.

LESSONS LEARNED

Policy briefs are two-page summaries of published research that address a single policy issue using language and graphics to make the science accessible to diverse audiences. Policy brief topics are selected by community advocates, based on collaborative research, and address a specific policy or regulation. Development is an iterative process of discussion with community representatives. Briefs have been used to provide information to advocates, state and national policymakers, and the public.

CONCLUSIONS

Disseminating CBPR results to address policy is needed. Collaborating with community partners to produce policy briefs ensures that information about concerns and struggles reflects their priorities.

The impacts of pesticide and nicotine exposures on functional brain networks in Latino immigrant workers

Latino immigrants that work on farms experience chronic exposures to potential neurotoxicants, such as pesticides, as part of their work. For tobacco farmworkers there is the additional risk of exposure to moderate to high doses of nicotine. Pesticide and nicotine exposures have been associated with neurological changes in the brain. Long-term exposure to cholinesterase-inhibiting pesticides, such as organophosphates and carbamates, and nicotine place this vulnerable population at risk for developing neurological dysfunction. In this study we examined whole-brain connectivity patterns and brain network properties of Latino immigrant workers. Comparisons were made between farmworkers and non-farmworkers using resting-state functional magnetic resonance imaging data and a mixed-effects modeling framework. We also evaluated how measures of pesticide and nicotine exposures contributed to the findings. Our results indicate that despite having the same functional connectivity density and strength, brain networks in farmworkers had more clustered and modular structures when compared to non-farmworkers. Our findings suggest increased functional specificity and decreased functional integration in farmworkers when compared to non-farmworkers. Cholinesterase activity was associated with population differences in community structure and the strength of brain network functional connections. Urinary cotinine, a marker of nicotine exposure, was associated with the differences in network community structure. Brain network differences between farmworkers and non-farmworkers, as well as pesticide and nicotine exposure effects on brain functional connections in this study, may illuminate underlying mechanisms that cause neurological implications in later life.

Olfactory Function in Latino Farmworkers: Subclinical Neurological Effects of Pesticide Exposure in a Vulnerable Population

OBJECTIVES

We compared olfactory function in pesticide-exposed Latino farmworkers and nonfarmworkers to explore its use as a subclinical indicator of neurological pesticide effects.

METHODS

We recruited 304 current farmworkers and 247 nonfarmworkers. All completed odor identification (14 odors) and threshold tests (16 concentrations of n-butanol) using a well-established methodology.

RESULTS

Farmworkers reported significantly greater lifetime pesticide exposure. Performance on both olfactory tests declined with age. Odor identification performance did not differ between groups. For odor threshold, farmworkers needed significantly higher concentrations to detect the odor. Results were unchanged when adjusted for sex, age, and smoking.

CONCLUSION

Olfactory function differences between farmworkers and nonfarmworkers suggest possible neurological effects. Because declining olfactory function is an early symptom of Parkinson disease and related conditions, it is a possible subclinical indicator of neurodegenerative disease in this vulnerable worker population.

Longitudinal Assessment of Blood Cholinesterase Activities Over 2 Consecutive Years Among Latino Nonfarmworkers and Pesticide-Exposed Farmworkers in North Carolina

OBJECTIVE

This study (1) describes patterns of whole blood total cholinesterase, acetylcholinesterase, and butyrylcholinesterase activities across the agricultural season, comparing farmworkers and nonfarmworkers; and (2) explores differences between farmworkers' and non-farmworkers' likelihood of cholinesterase depression.

METHODS

Blood samples from 210 Latino male farmworkers and 163 Latino workers with no occupational pesticide exposure collected 8 times across 2 agricultural seasons were analyzed. Mean cholinesterase activity levels and depressions 15% or more were compared by month.

RESULTS

Farmworkers had significantly lower total cholinesterase and butyrylcholinesterase activities in July and August and lower acetylcholinesterase activity in August. Farmworkers had significantly greater likelihood of cholinesterase depression for each cholinesterase measure across the agricultural season.

SIGNIFICANCE

A repeated-measures design across 2 years with a nonexposed control group demonstrated anticholinesterase effects in farmworkers. Current regulations designed to prevent pesticide exposure are not effective.

Urinary Cotinine Levels Among Latino Tobacco Farmworkers in North Carolina Compared to Latinos Not Employed in Agriculture

INTRODUCTION

This analysis describes urinary cotinine levels of North Carolina Latino farmworkers, compares cotinine levels of farmworkers to those of Latinos non-farmworkers, determines factors associated with farmworker cotinine levels, and determines if differences in farmworker and non-farmworker cotinine levels are associated with smoking.

METHODS

Data are from 63 farmworkers and 44 non-farmworkers who participated in a larger study of occupational exposures. Questionnaire data and urine samples collected in 2012 and 2013 are analyzed.

RESULTS

Farmworkers had urinary cotinine levels that were far greater than the non-farmworker group. Geometric mean (GM) urinary cotinine levels for farmworkers were 1808.22ng/ml in 2012, and 396.03ng/ml in 2013; corresponding GM levels for non-farmworkers were 4.68ng/ml and 9.03ng/ml. Farmworker GM cotinine levels were associated with harvesting tobacco (1242.77ng/ml vs. 471.26ng/ml; P = .0048), and working in wet shoes (1356.41ng/ml vs. 596.93ng/ml; P = .0148). Smoking did not account for cotinine level differences; the GM cotinine level for farmworkers who did not smoke was 541.31ng/ml; it was 199.40ng/ml for non-farmworkers who did smoke.

CONCLUSION

North Carolina farmworkers experience large nicotine doses. The long-term health effects of these doses are not known. Although procedures to reduce occupational nicotine exposure are known, no changes in work practices or in policies to protect workers have been implemented. Research on the health effects of occupational nicotine exposure must become a priority. Current knowledge of occupational transdermal nicotine exposure must be used to improve occupational safety practice and policy for tobacco workers.

IMPLICATIONS

This study documents the heavy burden of nicotine exposure and dose experienced by tobacco workers in North Carolina. Hundreds of thousands of farmworkers and farmers in the United States and Canada, as well as agricultural workers around the world, share this burden of nicotine exposure and dose. These results support the need to change work practices and regulations to protect workers. They also document the need to delineate the health effects of long-term exposure to high transdermal nicotine doses.

Economic Hardship and Depression Among Women in Latino Farmworker Families

Farmworker family members risk poor mental health due to stressors including poverty, relocation, and documentation status. This paper explores the relationship between farm-work related stressors and depressive symptoms in women of Latino farmworker families. 248 mothers of young children completed fixed-response interviews in Spanish. Measures included the Center for Epidemiologic Studies-Depression Scale, Migrant Farmworker Stress Inventory, and USDA Household Food Security Survey Module. Bivariate analyses indicated greater depressive symptoms with more economic hardship, more farm work-related stressors, greater age, and being unmarried. In multivariable logistic regression, economic hardship remained the only factor associated with depressive symptoms. Greater economic hardship, but not general farm work-related stress, is a main factor associated with depression in women of Latino farmworker families. Maternal depression can have consequences for both mothers and families. Mental health services for women in farmworker families should be targeted to those with the greatest economic challenges.

Sleep Quality Among Latino Farmworkers in North Carolina: Examination of the Job Control-Demand-Support Model

Sleep problems are associated with physical and mental health disorders and place individuals at an increased risk of workplace injuries. The demand-control-support model posits that job demands and the capacity to control work processes influence workers' level of distress, thereby affecting their physical and mental health; supervisor support can buffer the negative effect of high demands and low control. Data on the sleep quality and the organization of work of Latino men were collected in agricultural areas in North Carolina in 2012. 147 Mexican-born farmworkers ages 30 and older, most of whom had H-2A visas, provided information about sleep quality and organization of work. Most (83 %) farmworkers reported good sleep quality. The association between working more than 40 h per week and reporting poor sleep quality approached statistical significance. Additional research is needed to understand whether job demands, job control, and social support affect farmworkers' sleep quality.

Learning Ability as a Function of Practice: Does It Apply to Farmworkers?

OBJECTIVE

Farmworkers experience significant work-related health risks including pesticide-associated cognitive impairment. Practice effect is a surrogate for learning ability. This study examined differences in cognitive function and learning capacity in Latino farmworkers and nonfarmworkers.

METHODS

Tasks of learning and short-term memory, executive function and working memory, perceptual coding, and psychomotor function were assessed at baseline and 3-month follow-up in 136 farmworkers and 116 nonfarmworkers.

RESULTS

Farmworkers had better performance on visuospatial learning and short-term memory at baseline (P < 0.05). Nevertheless, nonfarmworkers showed more practice effects, or improvement on cognitive performance, at 3-month follow-up relative to farmworkers. Furthermore, the amount of improvement on visuospatial learning ability, short-term visuospatial memory, and perceptual coding ability was significantly higher in nonfarmworkers than in farmworkers.

CONCLUSIONS

Practice effects may serve as an additional cognitive readout to differentiate healthy individuals from those with cognitive impairment.

Housing and Neighborhood Characteristics and Latino Farmworker Family Well-Being

Housing quality and neighborhood characteristics affect individual health and family well-being. This analysis describes characteristics of farmworker housing and neighborhoods and delineates the associations of housing and local neighborhood with indicators of family well-being. Mothers in North Carolina farmworker families (n = 248) completed interviews in 2011-2012. Family well-being measures included stress, family conflict, and outward orientation. Housing measures included ownership and facilities, and neighborhood measures included heavy traffic and driving time to grocery stores. Families experienced elevated stress and conflict, and limited outward orientation. Few owned their homes, which were generally crowded. Few had enclosed play spaces for their children. For many, traffic made it difficult to walk on the street. Housing and neighborhood characteristics were related to increased stress and limited outward orientation. Housing and neighborhood characteristics are important for research on the health of families in vulnerable populations, such as farmworker families.

Profiles of Food Security for US Farmworker Households and Factors Related to Dynamic of Change

OBJECTIVES

We recruited 248 farmworker families with preschool-aged children in North Carolina and examined food security indicators over 24 months to identify food security patterns and examine the dynamic of change over time.

METHODS

Participants in the Niños Sanos study, conducted 2011 to 2014, completed quarterly food security assessments. Based on responses to items in the US Household Food Security Survey Module, we identified different states of food security by using hidden Markov model analysis, and examined factors associated with different states. We delineated factors associated with changes in state by using mixed-effect ordinal logistic regression.

RESULTS

About half of the households (51%) consistently stayed in the most food-secure state. The least food-secure state was transient, with only 29% probability of this state for 2 consecutive quarters. Seasonal (vs migrant) work status, having immigration documents (vs not documented), and season predicted higher levels of food security.

CONCLUSIONS

Heterogeneity in food security among farmworker households calls for tailoring intervention strategies. The transiency and unpredictability of low food security suggest that access to safety-net programs could reduce low food security risk in this population.

Assessing Assay Variability of Pesticide Metabolites in the Presence of Heavy Left-Censoring

Assessing assay variability for field samples in environmental research is challenging, since a quantitative assay is typically constrained by a lower limit of detection. The purpose of this paper is to compare three parametric models for assessing assay variability using duplicate data subject to heavy left-censoring. Efron information criterion (EIC) and Bayesian information criterion (BIC) are used to aid in model selections. Distributional parameter estimates are obtained using maximum likelihood estimation for bivariate lognormal, bivariate zero-inflated lognormal, and bivariate 3-component mixture models. We illustrate a practical application using duplicate pesticide data from the Community Participatory Approach to Measuring Farmworker Pesticide Exposure (PACE3) study. Furthermore, a simulation study is conducted to empirically evaluate the performance of the three models. The results from PACE3 indicate that the bivariate zero-inflated lognormal model is fairly competitive based on EIC or BIC. Further, total variability for the lognormal component can be decomposed into between-subject and within-subject variance based on this model. Assay variability estimates such as within-subject coefficient variation, minimum detectable change, and probability of k-fold difference can be easily derived under the bivariate zero-inflated lognormal model. Additionally, the assay variability is rather large for the PACE3 data. Therefore, apparent longitudinal change in pesticide exposure should be examined cautiously in the context of substantial assay variability.

Work Safety Climate, Safety Behaviors, and Occupational Injuries of Youth Farmworkers in North Carolina

OBJECTIVES

The aims of this project were to describe the work safety climate and the association between occupational safety behaviors and injuries among hired youth farmworkers in North Carolina (n = 87).

METHODS

We conducted personal interviews among a cross-sectional sample of youth farmworkers aged 10 to 17 years.

RESULTS

The majority of youths reported that work safety practices were very important to management, yet 38% stated that supervisors were only interested in "doing the job quickly and cheaply." Few youths reported appropriate work safety behavior, and 14% experienced an injury within the past 12 months. In bivariate analysis, perceptions of work safety climate were significantly associated with pesticide exposure risk factors for rewearing wet shoes (P = .01), wet clothes (P = .01), and shorts (P = .03).

CONCLUSIONS

Youth farmworkers perceived their work safety climate as being poor. Although additional research is needed to support these findings, these results strengthen the need to increase employer awareness to improve the safety climate for protecting youth farmworkers from harmful exposures and injuries.

Perceptions of housing conditions among migrant farmworkers and their families: implications for health, safety and social policy

INTRODUCTION

In the USA, migrant farmworkers are a vulnerable group due to their low socioeconomic status, risk of occupational exposures and injury, lack of social mobility, lack of adequate access to health services and dependency on employer for provided housing. Previous reports have documented migrant farmworker housing conditions to be variable, but poor overall. This paper explores the perceptions of housing conditions among migrant farmworkers in rural North Carolina, and develops an understanding of potential impacts of their housing on health and safety.

METHODS

This study used qualitative descriptive data and directed content analysis to analyse semi-structured interviews and photographs that were data elements of a larger community-based participatory research study designed to document housing quality and health among North Carolina farmworkers.

RESULTS

Many of the study participants described poor housing conditions that were reflected in the photographic analysis of the houses and camps. Specific problems described by the participants include exposure to pesticides, safety issues, pests, water supply and air quality, temperature and moisture.

CONCLUSIONS

This study describes migrant farmworkers' perceptions of housing quality and numerous potential impacts on health and safety. Research, social policy and practice-based implications derived from this research could serve to improve the health status of these individuals and their families. This study suggests there is much room for sustained advocacy and action, given that many of the farmworkers' descriptions and photographs depicted housing conditions below accepted standards of living. Access to adequate and safe employer-provided housing for migrant farmworkers should be considered a basic human right.

Job characteristics and work safety climate among North Carolina farmworkers with H-2A visas

ABSTRACT Migrant farmworkers are a vulnerable population. Migrant farmworkers with H-2A visas are the only agricultural workers with temporary work permits. Little research has directly focused on the job characteristics and work safety of workers with H-2A visas. This analysis (1) describes their personal and job characteristics, job hazards, and stressors; (2) describes their perceived work safety climate; and (3) examines associations of perceived work safety climate with job characteristics, job hazards, and stressors. Data are from a cross-sectional component of a larger study of farmworker pesticide exposure; in 2012 interviews were conducted with 163 migrant farmworkers with H-2A visas in North Carolina. The sample was limited to men aged 30 to 70 years. Migrant farmworkers with H-2A visas experience the same hazards as do other farmworkers. Their mean score on the Perceived Work Safety Climate Scale 25.5 (SD = 3.7) is similar to that of other farmworkers and other immigrant workers. Perceived work safety climate is associated with hours worked per week (P = .02), precarious employment (P < .001), planting and cultivating (P = .002), topping tobacco (P = .0012), and stress (P = .02). Perceived work safety climate is particularly important for migrant farmworkers with H-2A visas because their labor contracts limit their options to change employers. Additional research on the status of work safety climate among agricultural workers is needed, as well as on the factors that affect work safety climate and on the safety characteristics that are affected by work safety climate. Policy changes that lead to improved work safety climate should be considered.

Physical activity of preschool-aged Latino children in farmworker families

OBJECTIVE

To describe time spent in sedentary and moderate-to-vigorous physical activity (MVPA) by children in Latino farmworker families and delineate sources of variation in sedentary and MVPA.

METHOD

Data were from mother-child dyads (N = 248) in Latino farmworker households in North Carolina. Physical activity was assessed using accelerometers; mothers described their children's characteristics and their physical and social environments.

RESULTS

Children spent 6.2 hours/day sedentary (Median=369 minutes), and 6.0 minutes/day in MVPA. Children in Head Start spent more time sedentary, whereas children living where dogs roam freely were less sedentary. Children whose mothers limited screen time spent 2 more minutes in MVPA.

CONCLUSIONS

Preschool-aged Latino children in farmworker families are sedentary, engaging in little MVPA.

Lifetime and current pesticide exposure among Latino farmworkers in comparison to other Latino immigrants

BACKGROUND

Pesticide exposure poses a health risk for farmworkers. This analysis documents lifetime and current pesticide exposure of North Carolina Latino migrant farmworkers, with comparison to non-farmworker Latino immigrants.

METHODS

During May to October 2012, 235 Latino farmworkers and 212 Latino non-farmworkers completed interviews with items to construct measures of lifetime, current residential and occupational pesticide exposure.

RESULTS

Farmworkers experience levels of lifetime and residential pesticide exposure that are consistently greater than among non-farmworkers. Farmworkers report a large number of occupational pesticide exposures. Lifetime exposure and current residential pesticide exposure are related to social determinants. Education is inversely related to lifetime pesticide exposure for farmworkers and non-farmworkers; farmworkers with H-2A visas report greater residential pesticide exposure than those without H-2A visas.

CONCLUSIONS

Occupational safety policy needs to consider these patterns of lifetime exposure when setting standards. Health care providers should be aware of the lifetime and current exposure of this vulnerable population.

Pesticides present in migrant farmworker housing in North Carolina

BACKGROUND

Migrant farmworkers are exposed to pesticides at work. Housing provided to migrant farmworkers may also expose them to pesticides, increasing their health risks. This analysis (1) describes the presence of organophosphorous (OP) and pyrethroid pesticides in North Carolina migrant farmworker houses, and (2) delineates associations of farmworker camp characteristics with pesticide detection and concentration.

METHODS

In 2010, 186 migrant farmworkers camps in NC were recruited (participation rate of 82.3%); pesticide wipe samples for 176 houses were analyzed. Tobacco is the predominant hand-harvested crop in this region. Two farmworkers per camp completed interviews; a third assisted with a housing inspection. Gas chromatography-mass spectrometry was used to detect OP and pyrethroid pesticides. Covariates of pesticide detection and concentration were determined with ANOVA and Tobit regression.

RESULTS

OPs were found in 166 of 176 houses (average of 2.4/house); pyrethroids were found in 171 houses (average of 4.3/house). The number of different OPs detected in each camp and concentrations of these OPs were not associated with camp and housing characteristics. The number of different pyrethroids detected in each camp and concentrations of these pyrethroids were associated with camps having residents with H2-A visas, a posted North Carolina Department of Labor Certificate of Inspection, no barracks, fewer residents, no bedroom weather protection or floor violations, and no roaches.

CONCLUSIONS

Farmworkers are exposed to pesticides where they live. Policy on removing pesticides from farmworker houses is needed. Reducing pesticides in farmworker houses will reduce one health risk confronted by this vulnerable population.

Pesticide exposures to migrant farmworkers in Eastern NC: detection of metabolites in farmworker urine associated with housing violations and camp characteristics

BACKGROUND

The purpose of this paper is to present and evaluate descriptively bivariate associations between urinary metabolites of pesticides and herbicides and migrant camp conditions, violations, and personal worker behaviors at home for farmworkers who do not apply pesticides.

METHODS

We studied 183 migrant farmworker camps in eastern North Carolina in 2010. Data and urine samples were collected from 371 men. Predictor measures included violations in six domains of housing regulations and nonviolation characteristics and personal behaviors that might impact urinary metabolites.

RESULTS

Cockroaches and bathroom violations were predictive of increased exposure to pyrethroids and cyfluthrin/chlorpyrifos, respectively. Changing and storing clothing and shoes in sleeping rooms increased the number of detects for the diazinon metabolite.

CONCLUSIONS

Farmworkers had exposures to multiple chemicals. No single housing domain was identified as critical to mitigating housing-related exposure; specific attention should be paid to changing and storing soiled clothing in sleeping rooms, and insect infestations.

A Bayesian Multiple Imputation Method for Handling Longitudinal Pesticide Data with Values below the Limit of Detection

Environmental and biomedical research often produces data below the limit of detection (LOD), or left-censored data. Imputing explicit values for values < LOD in a multivariate setting, such as with longitudinal data, is difficult using a likelihood-based approach. A Bayesian multiple imputation (MI) method is introduced to handle left-censored multivariate data. A Gibbs sampler, which uses an iterative process, is employed to simulate the target multivariate distribution within a Bayesian framework. Following convergence, multiple plausible data sets are generated for analysis by standard statistical methods outside of a Bayesian framework. With explicit imputed values available variables can be analyzed as outcomes or predictors. We illustrate a practical application using longitudinal data from the Community Participatory Approach to Measuring Farmworker Pesticide Exposure (PACE3) study to evaluate the association between urinary acephate concentrations (indicating pesticide exposure) and self-reported potential pesticide poisoning symptoms. Additionally, a simulation study is used to evaluate the sampling property of the estimators for distributional parameters as well as regression coefficients estimated with the generalized estimating equation (GEE) approach. Results demonstrated that the Bayesian MI estimates performed well in most settings, and we recommend the use of this valid and feasible approach to analyze multivariate data with values < LOD.

Review of 2,4-dichlorophenoxyacetic acid (2,4-D) biomonitoring and epidemiology

A qualitative review of the epidemiological literature on the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and health after 2001 is presented. In order to compare the exposure of the general population, bystanders and occupational groups, their urinary levels were also reviewed. In the general population, 2,4-D exposure is at or near the level of detection (LOD). Among individuals with indirect exposure, i.e. bystanders, the urinary 2,4-D levels were also very low except in individuals with opportunity for direct contact with the herbicide. Occupational exposure, where exposure was highest, was positively correlated with behaviors related to the mixing, loading and applying process and use of personal protection. Information from biomonitoring studies increases our understanding of the validity of the exposure estimates used in epidemiology studies. The 2,4-D epidemiology literature after 2001 is broad and includes studies of cancer, reproductive toxicity, genotoxicity, and neurotoxicity. In general, a few publications have reported statistically significant associations. However, most lack precision and the results are not replicated in other independent studies. In the context of biomonitoring, the epidemiology data give no convincing or consistent evidence for any chronic adverse effect of 2,4-D in humans.

Have regulatory efforts to reduce organophosphorus insecticide exposures been effective?

BACKGROUND

The Food Quality Protection Act (FQPA) was signed into law in 1996 to strengthen the regulation of pesticide tolerances in food. Organophosphorus (OP) insecticides were the first group of pesticides reviewed by the U.S. Environmental Protection Agency (EPA) under the new law.

OBJECTIVE

Our goal was to determine whether urinary concentrations of dialkylphosphate (DAP) metabolites of OP pesticides declined between the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999-2004.

METHODS

Using mass spectrometry-based methods, we analyzed urine samples from a nationally representative sample of 2,874 adults 20-59 years of age in NHANES 1999-2004 and samples from a non-nationally representative sample of 197 adult participants for NHANES III (1988-1994) for six common DAP metabolites of OP pesticides.

RESULTS

Median urinary DAP concentrations decreased by more than half between NHANES III and NHANES 2003-2004. Reductions of about 50%-90% were also observed for 95th percentile concentrations of five of the six metabolites. Frequencies of detection (FODs) decreased in all six metabolites (< 50% reduction). On average, median and 95th percentile concentrations and FODs showed a larger decrease in diethylphosphate metabolites than dimethylphosphate metabolites.

CONCLUSIONS

Human exposure to OP insecticides as assessed by urinary DAP concentrations has decreased since the implementation of the FQPA, although we cannot be certain that U.S. EPA actions in response to the FQPA directly caused the decrease in DAP concentrations.

Migrant farmworker housing regulation violations in North Carolina

BACKGROUND

The quality of housing provided to migrant farmworkers is often criticized, but few studies have investigated these housing conditions. This analysis examines housing regulation violations experienced by migrant farmworkers in North Carolina, and the associations of camp characteristics with the presence of housing violations.

METHODS

Data were collected in183 eastern North Carolina migrant farmworker camps in 2010. Housing regulation violations for the domains of camp, sleeping room, bathroom, kitchen, laundry room, and general housing, as well as total violations were assessed using North Carolina Department of Labor standards.

RESULTS

Violations of housing regulations were common, ranging from 4 to 22 per camp. Housing regulation violations were common in all domains; the mean number of camp violations was 1.6, of sleeping room violations was 3.8, of bathroom violations was 4.5, of kitchen violations was 2.3, of laundry room violations was 1.2, and of general housing violations was 3.1. The mean number of total housing violations was 11.4. Several camp characteristics were consistently associated with the number of violations; camps with workers having H-2A visas, with North Carolina Department of Labor Certificates of Inspection posted, and assessed early in the season had fewer violations.

CONCLUSIONS

These results argue for regulatory changes to improve the quality of housing provided to migrant farmworkers, including stronger regulations and the more vigorous enforcement of existing regulations.

Wages, wage violations, and pesticide safety experienced by migrant farmworkers in North Carolina

Farmworkers have the potential to receive wages that fail to meet minimum wage standards. This analysis describes wages and minimum wage violations among farmworkers, and it determines associations of wage violations with personal characteristics and pesticide safety regulation violations. Data are from a cross-sectional survey of 300 eastern North Carolina farmworkers conducted in June through August, 2009. Most farmworkers (90.0%) were paid by the hour, but 11.7 percent received piece-rate pay. Wage violations were prevalent among farmworkers: 18.3 percent of all farmworkers, 45.3 percent of farmworkers without H-2A visas, and 3.6 percent of farmworkers with H-2A visas experienced wage violations. Most farmworkers experienced numerous pesticide safety violations. Personal characteristics were not associated with wage violations among farmworkers without H-2A visas, but some pesticide safety violations were associated with wage violations. The association of violations indicates that some growers generally violate regulations. Greater enforcement of all regulations is needed.

Experimental strategy for translational studies of organophosphorus pesticide neurotoxicity based on real-world occupational exposures to chlorpyrifos

Translational research is needed to understand and predict the neurotoxic consequences associated with repeated occupational exposures to organophosphorus pesticides (OPs). In this report, we describe a research strategy for identifying biomarkers of OP neurotoxicity, and we characterize pesticide application workers in Egypt's Menoufia Governorate who serve as our anchor human population for developing a parallel animal model with similar exposures and behavioral deficits and for examining the influence of human polymorphisms in cytochrome P450 (CYP) and paraoxonase 1 (PON1) enzymes on OP metabolism and toxicity. This population has previously been shown to have high occupational exposures and to exhibit a broad range of neurobehavioral deficits. In addition to observational studies of work practices in the field, questionnaires on demographics, lifestyle and work practices were administered to 146 Egyptian pesticide application workers applying pesticides to the cotton crop. Survey results indicated that the application workforce uses standard operating procedures and standardized equipment provided by Egypt's Ministry of Agriculture, which provides a workforce with a stable work history. We also found that few workers report using personal protective equipment (PPE), which likely contributes to the relatively high exposures reported in these application workers. In summary, this population provides a unique opportunity for identifying biomarkers of OP-induced neurotoxicity associated with occupational exposure.

Living and working safely: challenges for migrant and seasonal farmworkers

Migrant and seasonal farmworkers are essential to North Carolina agriculture, yet they experience major health risks. This commentary describes the characteristics of North Carolina farmworkers, important hazards they face, and the status of regulatory protections. Finally, it presents a summary of policy needed to protect the health of farmworkers.

Depressive symptoms and sleepiness among Latino farmworkers in eastern North Carolina

Depression and sleepiness are both risk factors for occupational accidents and unintentional injury. Relatively little is known about the experiences of these risk factors in the immigrant Latino farmworker population. This analysis uses prospective panel data from a sample of Latino farmworkers in eastern North Carolina that were collected at monthly intervals during the 2008 agricultural season to (1) describe depressive symptoms and daytime sleepiness among immigrant Latino farmworkers across the agricultural season; (2) delineate associations of depressive symptoms with sleepiness across time; and (3) determine whether depressive symptoms precede sleepiness, or if sleepiness precedes depressive symptoms. Results indicated that 45% of farmworkers experienced elevated depressive symptoms across the season, whereas 20% experienced elevated sleepiness. Elevated depressive symptoms were more common among farmworkers living in barracks, and less common among those living in trailers. Sleepiness was more common among women than men. There was no evidence that depressive symptoms contributed to sleepiness, or that sleepiness contributed to depressive symptoms. The pattern of results suggests that a substantial proportion of Latino farmworkers experience levels of depressive symptoms or sleepiness that places them at risk for occupational accident or unintentional injury. The results also suggest that depressive symptoms and sleepiness do not cause each other; rather, the association of depressive symptoms with sleepiness hints at the possibility of a common physiologic mechanism such as circadian disruption.

Biomarkers of chlorpyrifos exposure and effect in Egyptian cotton field workers

BACKGROUND

Chlorpyrifos (CPF), a widely used organophosphorus pesticide (OP), is metabolized to CPF-oxon, a potent cholinesterase (ChE) inhibitor, and trichloro-2-pyridinol (TCPy). Urinary TCPy is often used as a biomarker for CPF exposure, whereas blood ChE activity is considered an indicator of CPF toxicity. However, whether these biomarkers are dose related has not been studied extensively in populations with repeated daily OP exposures.

OBJECTIVE

We sought to determine the relationship between blood ChE and urinary TCPy during repeated occupational exposures to CPF.

METHODS

Daily urine samples and weekly blood samples were collected from pesticide workers (n=38) in Menoufia Governorate, Egypt, before, during, and after 9-17 consecutive days of CPF application to cotton fields. We compared blood butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) activities with the respective urinary TCPy concentrations in each worker.

RESULTS

Average TCPy levels during the middle of a 1- to 2-week CPF application period were significantly higher in pesticide applicators (6,437 µg/g creatinine) than in technicians (184 µg/g) and engineers (157 µg/g), both of whom are involved in supervising the application process. We observed a statistically significant inverse correlation between urinary TCPy and blood BuChE and AChE activities. The no-effect level (or inflection point) of the exposure-effect relationships has an average urinary TCPy level of 114 µg/g creatinine for BuChE and 3,161 µg/g creatinine for AChE.

CONCLUSIONS

Our findings demonstrate a dose-effect relationship between urinary TCPy and both plasma BuChE and red blood cell AChE in humans exposed occupationally to CPF. These findings will contribute to future risk assessment efforts for CPF exposure.

Hazardous materials on golf courses: experience and knowledge of golf course superintendents and grounds maintenance workers from seven states

BACKGROUND

The golf course industry has a growing Latino work force. Little occupational health research has addressed this work force. This article examines golf course superintendents' and Latino grounds maintenance workers' pesticide knowledge, beliefs, and safety training. In particular, it focuses on knowledge of and adherence to OSHA Right-to-Know regulations.

METHODS

In person, in-depth interviews were conducted with 10 golf course superintendents in five states and with 16 Latino grounds maintenance workers in four states.

RESULTS

Few superintendents were in compliance with Right-to-Know regulations or did pesticide safety training with all of their workers. Few workers had any pesticide safety knowledge. Most safety training on golf courses was rudimentary and focused on machine safety, and was usually conducted in the off-season or on rainy days, not before workers were assigned tasks.

CONCLUSIONS

More Right-to-Know training is necessary for superintendents and grounds maintenance workers. Culturally and linguistically appropriate Spanish language materials need to be developed or made more widely available to train workers. Better enforcement of safety and training regulations is necessary.