Using Life History Calendars to Estimate in Utero and Early Life Pesticide Exposure of Latinx Children in Farmworker Families

Neuroanatomical differences in Latinx children from rural farmworker families and urban non-farmworker families and related associations with pesticide exposure

Exposure to pesticides in humans may lead to changes in brain structure and function and increase the likelihood of experiencing neurodevelopmental disorders. Despite the potential risks, there is limited neuroimaging research on the effects of pesticide exposure on children, particularly during the critical period of brain development. Here we used voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) from magnetic resonance images (MRI) to investigate neuroanatomical differences between Latinx children (n = 71) from rural, farmworker families (FW; n = 48) and urban, non-farmworker families (NFW; n = 23). Data presented here serves as a baseline for our ongoing study examining the longitudinal effects of living in a rural environment on neurodevelopment and cognition in children. The VBM analysis revealed that NFW children had higher volume in several distinct regions of white matter compared to FW children. Tract-based spatial statistics (TBSS) of DTI data also indicated NFW children had higher fractional anisotropy (FA) in several key white matter tracts. Although the difference was not as pronounced as white matter, the VBM analysis also found higher gray matter volume in selected regions of the frontal lobe in NFW children. Notably, white matter and gray matter findings demonstrated a high degree of overlap in the medial frontal lobe, a brain region predominantly linked to decision-making, error processing, and attention functions. To gain further insights into the underlying causes of the observed differences in brain structure between the two groups, we examined the association of organochlorine (OC) and organophosphate (OP) exposure collected from passive dosimeter wristbands with brain structure. Based on our previous findings within this data set, demonstrating higher OC exposure in children from non-farmworker families, we hypothesized OC might play a critical role in structural differences between NFW and FW children. We discovered a significant positive correlation between the number of types of OC exposure and the structure of white matter. The regions with significant association with OC exposure were in agreement with the findings from the FW-NFW groups comparison analysis. In contrast, OPs did not have a statistically significant association with brain structure. This study is among the first multimodal neuroimaging studies examining the brain structure of children exposed to agricultural pesticides, specifically OC. These findings suggest OC pesticide exposure may disrupt normal brain development in children, highlighting the need for further neuroimaging studies within this vulnerable population.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

Depressive Symptoms of Latinx Women in Rural Farmworker and Urban Non-Farmworker Families in North Carolina

BACKGROUND

Mental health among low-income Latinx women in the United States (US), including those in farmworker families, is a health equity concern. This analysis (1) describes the depressive symptoms among Latinx women in rural farmworker families and urban non-farmworker families and (2) delineates immigration and acculturation, family composition and disruption, and financial characteristics associated with depressive symptoms experienced by these women.

METHODS

Data are from a 2019-2020 cross-sectional survey of 66 rural farmworker and 52 urban non-farmworker women with a child participating in a study of pesticide exposure and neurocognitive development. Depressive symptoms were measured with the CES-D Short Form.

RESULTS

The median (25th-75th percentiles) depressive symptom score reported was 2.0 (1.0-4.0), with 10 (8.5%) women having depressive symptom scores of 10 or greater. In bivariate analysis, among immigration and acculturation characteristics, women born in the USA and who spoke English fluently had lower depressive symptom scores. Among family composition and disruption characteristics, married women, and those with two adults in the household had lower depressive symptom scores. No financial status characteristic had statistically significant associations with depressive symptom score. In multivariate analysis, rural farmworker women had an expected median score one point lower than did urban non-farmworker women.

CONCLUSION

Addressing mental health among immigrant women, particularly those in farmworker families, is a complex undertaking. Rural versus urban locality provides a context for mental health. Determining the proximal determinants of locality requires further analysis.

Characterization of Lifetime Agrichemical Exposure Sequences Relative to International Migration in Foreign Born Latinx Agricultural Workers Living in South Florida

There is a limited understanding of how toxic exposures to agrichemicals vary relative to international migration over the life course. A life history calendar (LHC) was piloted to explore sequences of agrichemical exposure relative to international migration. LHCs were administered to 41 foreign born individuals from Mexico and Central America who had agricultural work experience during their lifetime and who were living in South Florida. Social sequence analysis was used to explore occupation-by-agrichemical events relative to migration. A three-cluster solution was used to classify low, moderate, and high lifetime exposure sequences. The odds of any perceived effects of agrichemicals on the body increased with time prior to migration in the moderate and high exposure sequence clusters and continued to increase 20% with each year following migration in the moderate exposure cluster. Workers with high lifetime agrichemical exposures prior to migrating internationally showed lower likelihoods of a perceived effect on the body following migration despite continued exposure. Further research on instrument validity is warranted.

Retrospective Assessment of Human-Chemical Interactions in Health-Disparity Populations: A Process Evaluation of Life History Calendars

Life-history calendars (LHCs) can produce retrospective data regarding numerous events, exposures, and sequences that have occurred across participants' lifespans. In this mixed-quantitative-and-qualitative-methods study, processes of LHC administration were evaluated in two populations experiencing health disparities: foreign-born agricultural workers (n = 41) and Indigenous people who used injection drugs (IPWIDS) (n = 40). LHC administrator and participant perspectives were elicited during follow-up survey activities. In both agricultural workers and IPWIDs, over half of participants reported that the LHC made it easier to remember things about the past, and participant age was associated with cumulative experience in different domains of interest. Qualitative findings suggested that data-collector training and the development of concise interview guides are critical for improving LHC data quality. Participants described ethical themes, including utilitarian, cathartic, and reflective aspects, of LHC participation. Future iterations of the LHC may benefit from providing free-form and open-ended spaces for participants to reflect on the LHC activity following LHC administration.

Comparing impact of pesticide exposure on cognitive abilities of Latinx children from rural farmworker and urban non-farmworker families in North Carolina

Pesticide exposure remains a health hazard despite extensive study into adverse effects. Children in vulnerable populations, such as Latinx children in farmworker families, are particularly at risk for exposure. Several studies have demonstrated the detrimental cognitive effects of prenatal exposure to pesticides, particularly organophosphates (OPs) within this high-risk group. However, results from studies investigating the cognitive effects of early childhood pesticide exposure are equivocal. Most studies examining the effects of pesticide exposure have used correlative analyses rather than examining populations with expected high and low exposure. The current study compares 8-year-old children from rural families of farmworkers and urban, non-farmworker families. We used the Weschler Intelligence Scale for Children - Fifth Edition (WISC-V) to assess cognitive performance in these children. We designed this study with the expectation that children from farmworker families would have greater exposure to agricultural pesticides than urban, non-farmworker children. This assumption of exposure to agricultural pesticides was confirmed in a recent report that assessed exposure probabilities using life history calendars. However, data from passive wristband sampling of acute (1-week) pesticide exposure from these same children indicate that both study populations have considerable pesticide exposure but to different chemicals. As expected the children of farmworkers had greater OP exposure than non-farmworker children, but the non-farmworker children had greater exposure to two other classes of insecticides (organochlorines [OCs] and pyrethroids). Our analyses considered these findings. A comparison of the cognitive scores between groups revealed that children from farmworker families had slightly higher performance on the Visual-Spatial Index (VSI) and Verbal Comprehension Index (VCI) when compared to children from non-farmworker families. Regression analyses where pesticide exposure was included as covariates revealed that OC exposure accounted for the largest portion of the group differences for both VSI and VCI. However, a post-hoc moderation analysis did not find significant interactions. The main study outcome was that the non-farmworker children exhibited lower WISC-V scores than the children from farmworker families, and the analyses incorporating pesticide exposure measures raise the hypothesis the that pervasive and persistent nature of a variety of pesticides may have adverse effects on the neurodevelopment of young Latinx children whether living in rural or non-farmworker environments.

Altered Default Mode Network Associated with Pesticide Exposure in Latinx Children from Rural Farmworker Families

Pesticide exposure has been associated with adverse cognitive and neurological effects. However, neuroimaging studies aimed at examining the impacts of pesticide exposure on brain networks underlying abnormal neurodevelopment in children remain limited. It has been demonstrated that pesticide exposure in children is associated with disrupted brain anatomy in regions that make up the default mode network (DMN), a subnetwork engaged across a diverse set of cognitive processes, particularly higher-order cognitive tasks. This study tested the hypothesis that functional brain network connectivity/topology in Latinx children from rural farmworker families (FW children) would differ from urban Latinx children from non-farmworker families (NFW children). We also tested the hypothesis that probable historic childhood exposure to pesticides among FW children would be associated with network connectivity/topology in a manner that parallels differences between FW and NFW children. We used brain networks from functional magnetic resonance imaging (fMRI) data from 78 children and a mixed-effects regression framework to test our hypotheses. We found that network topology was differently associated with the connection probability between FW and NFW children in the DMN. Our results also indicated that, among 48 FW children, historic reports of exposure to pesticides from prenatal to 96 months old were significantly associated with DMN topology, as hypothesized. Although the cause of the differences in brain networks between FW and NFW children cannot be determined using a cross-sectional study design, the observed associations between network connectivity/topology and historic exposure reports in FW children provide compelling evidence for a contribution of pesticide exposure on altering the DMN network organization in this vulnerable population. Although longitudinal follow-up of the children is necessary to further elucidate the cause and reveal the ultimate neurological implications, these findings raise serious concerns about the potential adverse health consequences from developmental neurotoxicity associated with pesticide exposure in this vulnerable population.

Adverse Childhood Experiences Among Low-Income, Latinx Children in Immigrant Families: Comparison of Children in Rural Farmworker and Urban Non-Farmworker Communities

Adverse childhood experiences (ACEs) are stressors that can have lifelong detrimental health effects. ACEs are a concern for children of immigrant parents. The low-income mothers of 75 rural farmworker and 63 urban non-farmworker 8-year old Latinx children in immigrant families completed a standardized ACEs inventory. 47.1% of mothers reported no ACEs, 33.3% reported 1, 8.7% reported 2, and 10.9% reported 3 or more. A logistic regression model indicated that urban versus rural children had a higher odds (OR = 2.35, 95% CI = 1.01, 5.48) of at least one ACE. Children living in families with 2 versus 1 adults (OR = 0.10, 95% CI = 0.02, 0.49) and 3 versus 1 adults (OR = 0.12, 95% CI = 0.02, 0.78) had a lower odds of at least one ACE. ACEs prevalence was similar to other children in immigrant families, with children living in urban communities having twice the likelihood of experiencing an ACE. Detailed research is needed on locality-based ACEs prevalence.

Pesticide exposure among Latinx children: Comparison of children in rural, farmworker and urban, non-farmworker communities

Personal pesticide exposure is not well characterized among children in vulnerable, immigrant communities. We used silicone wristbands in 2018-2019 to assess pesticide exposure in 8 year old Latinx boys and girls in rural, farmworker families (n = 73) and urban, non-farmworker families (n = 60) living in North Carolina who were enrolled in the PACE5 Study, a community-based participatory research study. We determined the detection and concentrations (ng/g) of 75 pesticides and pesticide degradation products in the silicone wristbands worn for one week using gas chromatography electron capture detection and employed gas chromatography mass spectrometry. Differences by personal and family characteristics were tested using analysis of variance or Wilcoxon Rank Sum tests when necessary. Pesticide concentrations above the limit of detection were analyzed, and reported as geometric means and 95% confidence intervals (CI). The most frequently detected pesticide classes were organochlorines (85.7%), pyrethroids (65.4%), and organophosphates (59.4%), with the most frequently detected specific pesticides being alpha-chlordane (69.2%), trans-nonachlor (67.7%), gamma-chlordane (66.2%), chlorpyrifos (54.9%), cypermethrin (49.6%), and trans-permethrin (39.1%). More of those children in urban, non-farmworker families had detections of organochlorines (93.3% vs. 79.5, p = 0.0228) and pyrethroids (75.0% vs. 57.5%, p = 0.0351) than did those in rural, farmworker families; more children in rural, farmworker families had detections for organophosphates (71.2% vs. 45.0%, p= 0.0022). Children in urban, non-farmworker families had greater concentrations of alpha-chlordane (geometric mean (GM) 18.98, 95% CI 14.14, 25.47 vs. 10.25, 95% CI 7.49, 14.03; p= 0.0055) and dieldrin (GM 17.38, 95% CI 12.78 23.62 vs. 8.10, 95% CI 5.47, 12.00; p= 0.0034) than did children in rural, farmworker families. These results support the position that pesticides are ubiquitous in the living environment for children in vulnerable, immigrant communities, and argue for greater effort in documenting the widespread nature of pesticide exposure among children, with greater effort to reduce pesticide exposure.

COVID-19 Pandemic Among Immigrant Latinx Farmworker and Non-farmworker Families: A Rural-Urban Comparison of Economic, Educational, Healthcare, and Immigration Concerns

COVID-19 has revealed social and health inequities in the United States. Structural inequalities have increased the likelihood of immigrants contracting COVID-19, by being essential workers and through poverty that forces this population to continue working. Rural and urban immigrant families may face different concerns. Using a telephone survey in May 2020 of 105 Latinx families in an existing study, quantitative and qualitative data were gathered on work and household economics, childcare and education, healthcare, and community climate. Analyses show that, although rural and urban groups experienced substantial economic effects, impacts were more acute for urban families. Rural workers reported fewer workplace protective measures for COVID-19. For both groups, fear and worry, particularly about finances and children, dominated reports of their situations with numerous reports of experiencing stress and anxiety. The experience of the pandemic is interpreted as an example of contextual vulnerability of a population already experiencing structural violence through social injustice. Policy implications are highlighted.

COVID-19 Pandemic Among Immigrant Latinx Farmworker and Non-farmworker Families: A Rural-Urban Comparison of Economic, Educational, Healthcare, and Immigration Concerns

COVID-19 has highlighted social and health injustices in the US. Structural inequalities have increased the likelihood of immigrants contracting COVID-19, by being essential workers and through poverty that forces this population to continue working. Rural and urban immigrant families may face different concerns. Using a telephone survey in May 2020 of 105 Latinx families in an existing study, quantitative and qualitative data were gathered on work and household economics, childcare and education, healthcare, and community climate. Analyses show that, although rural and urban groups experienced substantial economic effects, impacts were more acute for urban families. Rural workers reported fewer workplace protective measures for COVID-19. For both groups, fear and worry, particularly about finances and children, dominated reports of their situations with numerous reports of experiencing stress and anxiety. The experience of the pandemic is interpreted as an example of contextual vulnerability of a population already experiencing structural violence through social injustice.

COVID-19 Pandemic among Latinx Farmworker and Nonfarmworker Families in North Carolina: Knowledge, Risk Perceptions, and Preventive Behaviors

(1) Background: The COVID-19 pandemic poses substantial threats to Latinx farmworkers and other immigrants in food production and processing. Classified as essential, such workers cannot shelter at home. Therefore, knowledge and preventive behaviors are important to reduce COVID-19 spread in the community. (2) Methods: Respondents for 67 families with at least one farmworker (FWF) and 38 comparable families with no farmworkers (nonFWF) in North Carolina completed a telephone survey in May 2020. The survey queried knowledge of COVID-19, perceptions of its severity, self-efficacy, and preventive behaviors. Detailed data were collected to document household members’ social interaction and use of face coverings. (3) Results: Knowledge of COVID-19 and prevention methods was high in both groups, as was its perceived severity. NonFWF had higher self-efficacy for preventing infection. Both groups claimed to practice preventive behaviors, though FWF emphasized social avoidance and nonFWF emphasized personal hygiene. Detailed social interactions showed high rates of inter-personal contact at home, at work, and in the community with more mask use in nonFWF than FWF. (4) Conclusions: Despite high levels of knowledge and perceived severity for COVID-19, these immigrant families were engaged in frequent interpersonal contact that could expose community members and themselves to COVID-19.