Development of a life events/icon calendar questionnaire to ascertain occupational histories and other characteristics of migrant farmworkers

Research of Pesticide Metabolites in Human Brain Tumor Tissues by Chemometrics-Based Gas Chromatography-Mass Spectrometry Analysis for a Hypothetical Correlation between Pesticide Exposure and Risk Factor of Central Nervous System Tumors

Pesticides are widely used, resulting in continuing human exposure with potential health impacts. Some exposures related to agricultural works have been associated with neurological disorders. Since the 2000s, the hypothesis of the role of pesticides in the occurrence of central nervous system (CNS) tumors has been better documented in the literature. However, the etiology of childhood brain cancers still remains largely unknown. The major objective of this work was to assess the potential role of pesticide exposure as a risk factor for CNS tumors based on questionnaires and statistical analysis of information collected from patients hospitalized in the Neurosurgery Department of the Habib Bourguiba Hospital Medium in Sfax, Tunisia, during the period from January 1, 2022, to May 31, 2023. It also aimed to develop a simple and rapid analytical method by the gas chromatography-mass spectrometry technique for the research traces of pesticide metabolites in some collected human brain tumor tissues in order to more emphasize our hypothesis for such a correlation between pesticide exposure and brain tumor development. Patients with a history of high-risk exposure were selected to conduct further analysis. Chemometric methods were adapted to discern intrinsic variation between pathological and control groups and ascertain effective separation with the identification of differentially expressed metabolites accountable for such variations. Three samples revealed traces of pesticide metabolites that were mostly detected at an early age. The histopathological diagnosis was medulloblastoma for a 10-year-old child and high-grade gliomas for 27- and 35-year-old adults. The bivariate analyses (odds ratio >1 and P value <5%) confirmed the great probability of developing cancer by an exposure case. The Cox proportional hazards model revealed the risk of carcinogenicity beyond the age of 50 as a long-term effect of pesticide toxicity. Our study supports the correlation between pesticide exposure and the risk of development of human brain tumors, suggesting that preconception pesticide exposure, and possibly exposure during pregnancy, is associated with an increased childhood brain tumor risk. This hypothesis was enhanced in identifying traces of metabolites from the carbamate insecticide class known for their neurotoxicity and others from pyridazinone, organochlorines (OCs), triazole fungicide, and N-nitroso compounds known for their carcinogenicity. The 2D-OXYBLOT analysis confirmed the neurotoxicity effect of insecticides to induce oxidative damage in CNS cells. Aldicarb was implicated in brain carcinogenicity confirmed by the identification of oxime metabolites in a stress degradation study. Revealing "aziridine" metabolites from the OC class may better emphasize the theory of detecting traces of pesticide metabolites at an early age. Overall, our findings lead to the recommendation of limiting the residential use of pesticides and the support of public health policies serving this objective that we need to be vigilant in the postmarketing surveillance of human health impacts.

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.

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.

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

(1) Background: Early life exposure to neurotoxic chemicals can have later impacts on child health. Most research designs must assume that current exposure is similar to past. Life history calendar methods can help to provide data on early life exposure. (2) Methods: Life history calendars were completed by mothers of 8-year-old children from Latinx farmworker and non-farmworker families (n = 73 and 65, respectively). Measures were created of months exposure through living adjacent to farm fields and having household members who worked in jobs exposing them to toxic chemicals. Data were divided into time periods of in utero, early childhood (birth-35 months) and later childhood (36-96 months). Cluster analysis compared the measures for children from farmworker and non-farmworker parents. (3) Results: Although, as a group, children from farmworker families have greater lifetime months of probable exposure to pesticides than children in non-farmworker families, cluster analysis reveals groups of children who do not follow that pattern. (4) Conclusions: The life history calendar is a technique for obtaining data on early life toxic chemical exposure that may help assign children to proper exposure groups. Conducting secondary analyses using such information can help to clarify the association of exposures to health outcomes.

A task-based assessment of parental occupational exposure to pesticides and childhood acute lymphoblastic leukemia

OBJECTIVES

Associations between parental occupational pesticide exposure and childhood acute lymphoblastic leukemia (ALL) vary across studies, likely due to different exposure assessment methodologies.

METHODS

We assessed parental occupational pesticide exposure from the year before pregnancy to the child's third year of life for 669 children diagnosed with ALL and 1021 controls. We conducted expert rating using task-based job modules (JM) to estimate exposure to pesticides among farmer workers, gardeners, agricultural packers, and pesticide applicators. We compared this method to (1) partial JM using job titles and a brief description, but without completing the task-based questionnaire, and (2) job exposure matrix (JEM) linking job titles to the International Standard Classifications of Occupation Codes. We used unconditional logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for ALL cancer risk and pesticide exposure adjusting for child's sex, age, race/ethnicity and household income.

RESULTS

Compared to complete JMs, partial JMs and JEM led to 3.1% and 9.4% of parents with pesticide exposure misclassified, respectively. Misclassification was similar in cases and controls. Using complete JMs, we observed an increased risk of ALL for paternal occupational exposure to any pesticides (OR=1.7; 95% CI=1.2, 2.5), with higher risks reported for pesticides to treat nut crops (OR=4.5; 95% CI=0.9, 23.0), and for children diagnosed before five years of age (OR=2.3; 95% CI: 1.3, 4.1). Exposure misclassification from JEM attenuated these associations by about 57%. Maternal occupational pesticide exposure before and after birth was not associated with ALL.

CONCLUSIONS

The risk of ALL was elevated in young children with paternal occupational pesticide exposure during the perinatal period, using more detailed occupational information for exposure classification.

An Icon-based Interview for the Assessment of Occupational Pesticide Exposure in a Case–Control Study of Childhood Leukemia

An icon-calendar interview form (ICF) for a case-control study of childhood leukemias and parental exposures to pesticides is described. It includes calendar sheets, icons for life events, crops, jobs, regions, non-agricultural jobs, application techniques and personal protection, markers for durations of exposure patterns, and checklists of pesticides. The ICF collects monthly data from two years before birth until diagnosis of cancer (index children) or until either the interview date or age 15 (controls). Data ascertainment was easy in 62% of interviews, moderately easy in 32%, and difficult in 6%. Seventy-eight subjects delivered data on specific pesticides with pesticide checklists, which improved identification of pesticides. ICF performs satisfactorily for crops, tasks, and other determinants of exposure. Data on pesticides will be further improved by introducing external data use on different crops, time periods, and regions, and by exposure modeling for 27 pesticides.

Ascertainment of occupational histories in the working population: the occupational history calendar approach

BACKGROUND

self-reported occupational histories are an important means for collecting historical data in epidemiological studies. An occupational history calendar (OHC) has been developed for use alongside a national occupational hazard surveillance tool. This study presents the systematic development of the OHC and compares work histories collected via this calendar to those collected via a traditional questionnaire.

METHODS

the paper describes the systematic development of an OHC for use in the general working population. A comparison of data quality and recall was undertaken in 51 participants where both tools were administered.

RESULTS

the OHC enhanced job recall compared with the traditional questionnaire. Good agreement in the data captured by both tools was observed, with the exception of hazard exposures.

CONCLUSIONS

a calendar approach is suitable for collecting occupational histories from the general working population. Despite enhancing job recall the OHC approach has some shortcomings outweighing this advantage in large-scale population surveillance.

Assessing environmental and occupational risk factors for lung cancer in Mexican-Americans

BACKGROUND

We investigated environmental and occupational exposures and smoking history (while controlling for demographics) in a population of Mexican-American lung cancer cases and controls from the Houston metropolitan area.

METHODS

Data were collected between 1991 and 2005 as part of an on-going multi-racial/ethnic, lung cancer case-control study. Cases included 212 Mexican-American lung cancer cases from UT MD Anderson Cancer Center. Controls (n = 328) were recruited from Houston's largest multispecialty group practice and frequency matched to the cases by age (± 5 years), sex, and ethnicity. Environmental and occupational factors were analyzed and odds ratios and 95% confidence intervals were calculated using logistic regression.

RESULTS

We detected elevated risks of lung cancer associated with pesticide exposure and found conventional and antimicrobial (e.g., sterilizers, disinfectants, antiseptics) pesticides were associated with an increased risk of lung cancer in Mexican-Americans (conventional pesticides and antimicrobial pesticides combined: OR = 1.80, 95% CI 1.13-2.86; conventional pesticides: OR = 2.05, 95% CI 1.23-2.39; antimicrobial pesticides: OR = 2.48, 95% CI 1.46-4.21).

CONCLUSIONS

Although we found over a two-fold increased risk of lung cancer among Mexican-Americans for pesticides, we could not identify individual pesticides. Our findings are an important preliminary step in identifying factors that are specifically associated with lung cancer risk among Mexican Americans.

Repeated pesticide exposure among North Carolina migrant and seasonal farmworkers

BACKGROUND

Limited data document the multiple and repeated pesticide absorption experienced by farmworkers in an agricultural season or their risk factors.

METHODS

Data were collected from 196 farmworkers four times at monthly intervals in 2007. Urine samples were tested for 12 pesticide urinary metabolites. Questionnaire data provided measures of exposure risks.

RESULTS

Farmworkers had at least one detection for many pesticide urinary metabolites; for example, 84.2% had at least one detection for acephate, 88.8% for 3,5,6-trichloro-2-pyridinol. Most farmworkers had multiple detections for specific metabolites; for example, 64.8% had two or more detections for acephate, 64.8% for 3,5,6-trichloro-2-pyridinol, 79.1% for 3-phenoxybenzoic acid, and 86.7% for 2,4-dichlorophenoxyacetic acid. Housing type had a consistent significant association with metabolite detections.

CONCLUSIONS

Farmworkers are exposed to multiple pesticides across an agricultural season, and they experience repeated exposures to the same pesticides. Reducing farmworker pesticide exposure and delineating the health outcomes of this exposure require more detailed data. Am. J. Ind. Med. 53:802-813, 2010. (c) 2010 Wiley-Liss, Inc.

Development of a computer-based survey instrument for organophosphate and N-methyl-carbamate exposure assessment among agricultural pesticide handlers

BACKGROUND

Assessment of occupational pesticide exposures based on self-reported information can be challenging, particularly with immigrant farm worker populations for whom specialized methods are needed to address language and cultural barriers and account for limited literacy. An audio computer-assisted self-interview (A-CASI) survey instrument was developed to collect information about organophosphate (OP) and N-methyl-carbamate (CB) exposures and other personal characteristics among male agricultural pesticide handlers for an ongoing cholinesterase biomonitoring study in Washington State.

OBJECTIVES

To assess the feasibility of collecting data using the A-CASI instrument and evaluate reliability for a subset of survey items.

METHODS

The survey consisted of 64 items administered in Spanish or English on a touch-screen tablet computer. Participants listened to digitally recorded questions on headphones and selected responses on the screen, most of which were displayed as images or icons to facilitate participation of low literacy respondents. From 2006-2008, a total of 195 participants completed the survey during the OP/CB application seasons on at least one occasion. Percent agreement and kappa coefficients were calculated to evaluate test-retest reliability for selected characteristics among 45 participants who completed the survey on two separate occasions within the same year.

RESULTS

Almost all participants self-identified as Hispanic or Latino (98%), and 97% completed the survey in Spanish. Most participants completed the survey in a half-hour or less, with minimal assistance from on-site research staff. Analyses of test-retest reliability showed substantial agreement for most demographic, work history, and health characteristics and at least moderate agreement for most variables related to personal protective equipment use during pesticide applications.

CONCLUSIONS

This A-CASI survey instrument is a novel method that has been used successfully to collect information about OP/CB exposures and other personal characteristics among Spanish-speaking agricultural pesticide handlers.

Does living near heavy industry cause lung cancer in women? A case-control study using life grid interviews

BACKGROUND

The incidence of lung cancer among women is high in the highly industrialised area of Teesside in north-east England. Previous research has implicated industrial pollution as a possible cause. A study was undertaken to investigate whether prolonged residence close to heavy industry is associated with lung cancer among women in Teesside.

METHODS

Two hundred and four women aged <80 years with incident primary lung cancer and 339 age matched community controls were recruited to a population based case-control study. Life course residential, occupational, and active and passive smoking histories were obtained using an interviewer administered questionnaire.

RESULTS

The age adjusted odds ratio (OR) for lung cancer among people living >25 years v 0 years near (within 0-5 km) heavy industry in Teesside was 2.13 (95% CI 1.34 to 3.38). After adjustment for confounding factors the OR was 1.83 (95% CI 0.82 to 4.08) for >25 years or 1.10 (95% CI 0.96 to 1.26) for an additional 10 years living near industry. ORs were similar after residence near heavy industry outside Teesside was also included, and when latency was allowed for by disregarding residential exposures within the last 20 years. Adjustment for active smoking had the greatest effect on the OR.

CONCLUSIONS

This population based study using life grid interviews for life course exposure assessment has addressed many deficiencies in the design of previous studies. The findings support those in most of the international literature of a modestly raised risk of lung cancer with prolonged residence close to heavy industry, although the confidence intervals were wide. The effect of air pollution on the incidence of lung cancer merits continued study.

Building informed consent for cholinesterase monitoring among pesticide handlers in Washington State

BACKGROUND

Pesticide handlers in Washington State are predominantly Mexican and, therefore, require a culturally appropriate process of informed consent. In addition, members of this occupational group are vulnerable to coercion because of poverty, lack of insurance, inability to read, and employment status

METHODS

To create a process of culturally competent informed consent for Washington State's cholinesterase monitoring program, we used focus groups to collect data about cultural beliefs, attitudes, knowledge, language, and traditions of Mexican-American pesticide handlers. With this information, we developed a final consent form and evaluated it using a 10-item test-retest questionnaire in a sample of 103 handlers.

RESULTS

Using qualitative methods, we created English and Spanish consent forms that incorporated culturally defined risk information. Both the written and audiotape formats significantly improved comprehension; but, for subjects with less than 7 years of schooling, audiotapes in Spanish yielded significantly higher scores (mean comprehension score 7.0 vs. 6.1, t = - 2.2, P = 0.03).

CONCLUSIONS

Culturally competent informed consent for particularly vulnerable populations of non-native speakers of English is possible. It requires both knowledge of specific cultural elements and the application of appropriate technology.

An audiotaped mental health evaluation tool for Hispanic immigrants with a range of literacy levels

Debilitating mental illness is treatable if found. There is no validated self-administered mental illness evaluation tool for immigrant Hispanic farm workers with variable literacy levels. This study tested sensitivity and specificity of an audiotaped survey developed for low literacy levels compared with standard interview instruments. Subjects from 11 migrant camps completed a self-administered audiotaped survey in Spanish to diagnose major depression, substance abuse, panic and generalized anxiety, and domestic violence. Primary care clinics assisted in finding camps and provided follow-up treatment. For 154 men and 156 women, the audio tool was most sensitive for major depression and specific for anxiety disorder, alcohol abuse, and domestic violence. Seventy percent of those diagnosed with major depression received appropriate treatment. This study validated an inexpensive, self-administered audio tool to evaluate the mental health of immigrant Hispanic farm workers with a wide range of literacy levels.

Glycophorin A is a potential biomarker for the mutagenic effects of pesticides

For individuals with multiple exposures to bone marrow mutagens the glycophorin A (GPA) assay appears to detect the cumulative genotoxic effects of these nonspecific exposures. To determine whether workers exposed to organophosphates and/or carbamate pesticides have more GPA variants compared with controls, this cross-sectional cohort study examined 67 Latino farm workers, most of whom were exposed to organophosphate or carbamate pesticides, and 68 age-, gender-, ethnicity-, and education-matched reference subjects. Of the 27 participants who completed the questionnaire and had the M/N alleleotype required for the GPA assay, the N/N variant frequency was 9.1 x 10(-6) in the ten subjects with more than 1,500 cumulative hours of exposure vs 3.8 x 10(-6) in the six referent subjects with no known pesticide exposure (p = 0.097). A consistent trend with increasing cumulative exposure was found for N/N and O/N allele-loss frequencies when exposures were stratified into three groups. Despite the small sample size due to the alleleotype restriction, these findings support the hypothesis that some pesticides are mutagenic to hematopoietic stem cells.

Use of qualitative methods to map job tasks and exposures to occupational hazards for commercial fishermen

BACKGROUND

Understanding job tasks and estimating occupational exposures is difficult for self-employed or autonomous workers, who tend to be dispersed, with no fixed workplace, employment records, or historical exposure measurements.

METHODS

We used ethnographic methods to collect work information for southern commercial fishermen. Major activities were mapped using the seasonal round, an anthropological tool that records activities of groups whose lifeways depend on natural cycles.

RESULTS

Fishermen's work schedules depended on boat size, gear, market fluctuations, and regulations, as well as season. The seasonal round guided the analysis of qualitative data on annual cycles of activities increasing understanding of exposures and their variation.

CONCLUSIONS

Combined with detailed exposure information this framework for organizing and categorizing seasonal activities could improve accuracy of exposure information and guide quantitative analysis in work settings that challenge standard exposure assessment methods.

Ethical issues in conducting migrant farmworker studies

Migrant farmworkers should be considered a vulnerable population because they work in a hazardous industry, are often members of an ethnic minority, have known difficulty in accessing health care, and are often of lower socioeconomic status. For these reasons, too, it is extremely important to conduct health-related research with this often-underserved group. However, because migrant farmworkers are vulnerable, investigators must be especially vigilant in protecting them from the potential harms of research and in ensuring that the special ethical issues that arise in research with this population are identified and addressed for every project. In response to the National Cancer Institute's concerns about the feasibility of conducting epidemiologic studies among migrant farmworkers, researchers undertook four feasibility studies near the Texas-Mexico border. Each study raised different, complex ethical questions that challenged the investigators, but whose resolution turned out to be crucial to the success of the studies.

Health Effects of Chronic Pesticide Exposure: Cancer and Neurotoxicity

Pesticides are widely used in agricultural and other settings, resulting in continuing human exposure. Epidemiologic studies indicate that, despite premarket animal testing, current exposures are associated with risks to human health. In this review, we describe the routes of pesticide exposures occurring today, and summarize and evaluate the epidemiologic studies of pesticide-related carcinogenicity and neurotoxicity in adults. Better understanding of the patterns of exposure, the underlying variability within the human population, and the links between the animal toxicology data and human health effects will improve the evaluation of the risks to human health posed by pesticides. Improving epidemiology studies and integrating this information with toxicology data will allow the human health risks of pesticide exposure to be more accurately judged by public health policy makers.

Determining the probability of pesticide exposures among migrant farmworkers: results from a feasibility study

BACKGROUND

Migrant and seasonal farmworkers are exposed to pesticides through their work with crops and livestock. Because workers are usually unaware of the pesticides applied, specific pesticide exposures cannot be determined by interviews. We conducted a study to determine the feasibility of identifying probable pesticide exposures based on work histories.

METHODS

The study included 162 farm workers in seven states. Interviewers obtained a lifetime work history including the crops, tasks, months, and locations worked. We investigated the availability of survey data on pesticide use for crops and livestock in the seven pilot states. Probabilities of use for pesticide types (herbicides, insecticides, fungicides, etc.) and specific chemicals were calculated from the available data for two farm workers. The work histories were chosen to illustrate how the quality of the pesticide use information varied across crops, states, and years.

RESULTS

For most vegetable and fruit crops there were regional pesticide use data in the late 1970s, no data in the 1980s, and state-specific data every other year in the 1990s. Annual use surveys for cotton and potatoes began in the late 1980s. For a few crops, including asparagus, broccoli, lettuce, strawberries, plums, and Christmas trees, there were no federal data or data from the seven states before the 1990s.

CONCLUSIONS

We conclude that identifying probable pesticide exposures is feasible in some locations. However, the lack of pesticide use data before the 1990s for many crops will limit the quality of historic exposure assessment for most workers.

Organophosphate pesticide residues in urine of farmworkers and their children in Fresno County, California

BACKGROUND

Childhood cancer, notably leukemia, brain cancer, non-Hodgkin's lymphoma, soft tissue sarcoma, and Hodgkin's disease, has been associated with pesticide exposure, often with greater relative risks than among exposed adults, suggesting greater susceptibility in children. These differences in risk may be due to developmental factors or differences in pesticide exposure.

METHODS

A feasibility study was conducted to determine levels of pesticide metabolites in urine of adults (n = 18) and children (n = 9) in Fresno County, California, an intensely agricultural county in the Central San Joaquin Valley. Spot urine samples were obtained and analyzed for six metabolites of organophosphate (OP) pesticides using gas chromatography with flame photometric detection methods. The metabolites of OP pesticides included DMP, DEP, DMTP, DMDTP, DETP, and DEDTP.

RESULTS

Levels were generally low for both adults and children for most metabolites tested. Frequencies of detection ranged from 0 to 37%, with mean levels ranging from non-detectable to 13.22 ppb. However, levels of several metabolites were higher in children than in adults. The most frequently detected metabolite, DMP, was found among 44% of the children and 33% of the adults. DMTP was detected among 33% of the children and 28% of the adults.

CONCLUSIONS

These results are difficult to interpret given the sampling variation associated with the small sample size. Nevertheless, because OP pesticides have been associated with increased cancer risk in animal and human studies, these results indicate a need to closely monitor children's exposure to environmental chemicals.

A method for assessing occupational pesticide exposures of farmworkers

BACKGROUND

The health of farmworkers as related to pesticide exposure is of concern but assessing exposures for epidemiologic studies requires different techniques than approaches used for studies of industrial workers.

METHODS

A review of the literature identified possible factors that affect exposure intensity. A model was developed to estimate an exposure score. Exposures in the literature were estimated using the model and compared to the measurements in the literature.

RESULTS

Three studies were found with information appropriate for evaluation of the model. There was a statistical difference between the means of the scores corresponding to above and below the median of the measurements. The correlation coefficient between the scores and the measurements from the literature was 0.77.

CONCLUSIONS

Although the evaluation was limited, the model appeared to work well, but more testing is needed. More research is also needed to increase understanding of what affects the exposures of these workers.