Assessing the feasibility of epidemiologic research on migrant and seasonal farmworkers: an overview

Health care service utilization of documented and undocumented hired farmworkers in the U.S

This article analyzes issues related to U.S. hired farmworkers' utilization of health care services and their specific choices among health care provider and health bill payment method options. Using data from the National Agricultural Workers Surveys for the years 2000-2012, this article employs propensity score matching and probit estimation techniques to examine the health care utilization of hired farmworkers. This study's results indicate that undocumented hired farmworkers are 10.7 and 3% less likely to use U.S. and foreign health care, respectively, compared to documented farmworkers. Health insurance is found to significantly increase hired farmworkers' use of U.S. health care by 22.3%. Notably, compared to their documented working peers, undocumented workers are much less likely to patronize private clinics. They are even less likely to rely on migrant health centers even when these providers are their most viable sources of health care service.

Cardiovascular disease risk factors among Latino migrant and seasonal farmworkers

Migrant and seasonal (MS) farmworkers are an important component of the US economy. Their unique occupational health concerns have garnered research, but chronic disease research in this population is lacking. It is unclear whether health differences exist between migrant (those who migrate to and travel a distance from the home environment and thus live in temporary housing for the purpose of employment) and seasonal workers (those who work in the agricultural industry on a seasonal basis, whose long-term home environments are often near work locations and thus may be considered more "settled"), since most research presents MS farmworkers as a homogenous group. This study explored potential differences in cardiovascular disease risk factors, (i.e., diabetes, current smoking, obesity, hypertension, and hypercholesterolemia) by sex and MS status among a sample of 282 English- and Spanish- speaking Latino MS farmworkers in the Midwest using cross-sectional survey and clinical laboratory data. Results showed that in multivariate logistic regression analyses, migrant workers (odds ratio [OR] = 2.15) had a higher likelihood of being obese compared with seasonal workers (P < .05). MS farmworkers did not differ in likelihood of smoking, diabetes, hypertension, or hypercholesterolemia. In adjusted analyses, females were more likely to be obese (OR = 3.29) and have diabetes (OR = 4.74) compared with males (P < .05); and males were more likely to be current smokers (OR = 7.50) as compared with females (P < .05). This study provides insight into chronic health concerns among this predominantly Latino farmworker population and suggests that future prevention and intervention research may need to focus on sex differences rather than MS farmworker status.

Variability in the take-home pathway: farmworkers and non-farmworkers and their children

Organophosphate pesticides (OPs) are related to ill health among adults, including farmworkers who are exposed to OPs as part of their regular work. Children of both farmworkers and non-farmworkers in agricultural communities may also be affected by pesticide exposure. Study groups of 100 farmworkers with a referent child (aged 2-6 years) and 100 non-farmworkers with a referent child were recruited to participate in three data collection periods over the course of a year. At each collection, participants provided three urine samples within 5 days, and homes and vehicles were vacuumed to collect pesticide residues in dust. In thinning and harvest seasons, farmworkers and their children had higher dimethyl urinary metabolites than non-farmworkers and their children. During the non-spray season, the urinary metabolites levels decreased among farmworkers to a level comparable to that of non-farmworkers. Farmworkers consistently had higher pesticide residues in their home and vehicle dust. Differences exist between farmworkers and non-farmworkers in urinary metabolites, and the differences extended throughout the agricultural seasons.OP metabolites are seen at much higher levels for farmworkers and their children than for non-farmworkers and their children during agricultural seasons when OPs are in use. These metabolite levels were significantly higher than the nationwide NHANES IV survey and up to 10-fold higher than other rural agricultural studies.

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.

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.

The health of California's immigrant hired farmworkers

BACKGROUND

Hispanic immigrant workers dominate California's hired farm workforce. Little is known about their health status; even less is known about those lacking employment authorization.

METHODS

The California Agricultural Workers Health Survey (CAWHS) was a statewide cross-sectional household survey conducted in 1999. Six hundred fifty-four workers completed in-person interviews, comprehensive physical examinations, and personal risk behavior interviews.

RESULTS

The CAWHS PE Sample is comprised mostly of young Mexican men who lack health insurance and present elevated prevalence of indicators of chronic disease: overweight, obesity, high blood pressure, and high serum cholesterol. The self-reported, cumulative, farm work career incidence of paid claims for occupational injury under workers compensation was 27% for males and 11% for females.

CONCLUSIONS

The survey finds elevated prevalence of indicators of chronic disease but lack of health care access. Participants without employment authorization reported a greater prevalence of high-risk behaviors, such as binge drinking, and were less knowledgeable about workplace protections.

Organophosphate pesticide exposure and work in pome fruit: evidence for the take-home pesticide pathway

Organophosphate (OP) pesticides are commonly used in the United States, and farmworkers are at risk for chronic exposure. Using a sample of 218 farmworkers in 24 communities and labor camps in eastern Washington State, we examined the association between agricultural crop and OP pesticide metabolite concentrations in urine samples of adult farmworkers and their children and OP pesticide residues in house and vehicle dust samples. Commonly reported crops were apples (71.6%), cherries (59.6%), pears (37.2%), grapes (27.1%), hops (22.9%), and peaches (12.4%). Crops were grouped into two main categories: pome fruits (apples and pears) and non-pome fruits. Farmworkers who worked in the pome fruits had significantly higher concentrations of dimethyl pesticide metabolites in their urine and elevated azinphos-methyl concentrations in their homes and vehicles than workers who did not work in these crops. Among pome-fruit workers, those who worked in both apples and pears had higher urinary metabolites concentrations and pesticide residue concentrations in dust than did those who worked in a single pome fruit. Children living in households with pome-fruit workers were found to have higher concentrations of urinary dimethyl metabolites than did children of non-pome-fruit workers. Adult urinary concentrations showed significant correlations with both the vehicle and house-dust azinphos-methyl concentrations, and child urinary concentrations were correlated significantly with adult urinary concentrations and with the house-dust azinphos-methyl concentration. The results provide support for the take-home pathway of pesticide exposure and show an association between measures of pesticide exposure and the number of pome-fruit crops worked by farmworkers.

Studying health outcomes in farmworker populations exposed to pesticides

A major goal of studying farmworkers is to better understand how their work environment, including exposure to pesticides, affects their health. Although a number of health conditions have been associated with pesticide exposure, clear linkages have yet to be made between exposure and health effects except in cases of acute pesticide exposure. In this article, we review the most common health end points that have been studied and describe the epidemiologic challenges encountered in studying these health effects of pesticides among farmworkers, including the difficulties in accessing the population and challenges associated with obtaining health end point data. The assessment of neurobehavioral health effects serves as one of the most common and best examples of an approach used to study health outcomes in farmworkers and other populations exposed to pesticides. We review the current limitations in neurobehavioral assessment and strategies to improve these analytical methods. Emerging techniques to improve our assessment of health effects associated with pesticide exposure are reviewed. These techniques, which in most cases have not been applied to farmworker populations, hold promise in our ability to study and understand the relationship between pesticide exposure and a variety of health effects in this population. Key words: biomarkers, cancer, epidemiology, health outcomes, immigrants, neurobehavioral, neuropathy, pesticides.

Agricultural injury in California migrant Hispanic farm workers

BACKGROUND

Agriculture is among the most hazardous industries in the United States.

METHODS

A longitudinal study of injury among migrant Hispanic farm workers residing in six Northern California Migrant Family Housing Centers (MHCs) during the 1997 harvest season was conducted. Participants completed an initial interviewer-administered work-and-health questionnaire at the beginning of the harvest season addressing the preceding year; there were three periodic follow-up surveys.

RESULTS

There were 1,201 adult farm workers (participation 85.2%) who completed the initial questionnaire. Of these, 837 (69.7%) completed the final follow-up survey. There were 86 agricultural injuries (incidence 9.3/100 full-time equivalent employees (FTEs), 95% CI 7.5-11.5/100 FTE). Increased risk for agricultural injury occurred among women paid piece-rate (RR 4.9, 95% CI 1.8-12.8). Sprains and strains were most common (31%), followed by lacerations (12%).

CONCLUSIONS

Agricultural injury experience in this cohort is comparable to that of agricultural workers in other U.S. settings. Increased risk among women paid piece-rate suggests further study and potential policy changes regarding payment regimens. Heterogeneity of injury in this population presents a major prevention challenge. In view of high frequency of strain and sprain injuries, ergonomic interventions deserve further study.

Injury risks in children of California migrant Hispanic farm worker families

BACKGROUND

Few data are available addressing occupational and other injury risks among children of migrant Hispanic farm workers.

METHODS

We conducted the U.C. Davis Farm Worker Injury Study (UCD-FWIS), a longitudinal follow-up study of injury among migrant Hispanic farm worker families living in six Northern California Migrant Housing Centers (MHCs). Nine hundred forty-one children (age < 18 years) were interviewed through parental proxy.

RESULTS

Fifty-one injuries resulting in medical care or at least one-half day of lost or restricted work or school time occurred among 49 children (3.8 injuries/100 person-years). Open wounds (31.4%) and fractures (29.4%) were most common. Falls comprised over one-third of the cases, followed by being struck and bicycle injuries. Over three-quarters of subjects never use a helmet when riding a bicycle. Seventy-eight (8.3%) children reported employment in the preceding year, typically involving manual agricultural tasks. Two injury cases were occupational and involved agricultural work.

CONCLUSIONS

Occupational injury was uncommon in this group of children in migrant Hispanic farm worker families. Injury prevention in this population should include a focus on the home and surrounding environment as well as the work place.

Assessment of occupational health and safety risks of farmworkers in Colorado

BACKGROUND

Migrant farmworkers face a variety of hazards including exposure to pesticides and agricultural chemicals. However, few studies have quantatively evaluated these risks.

METHODS

Hazards were assessed during 32 field surveys conducted in the agricultural fields and 15 surveys at five camps. Observations of 1,461 farmworkers for potential hazards were recorded. Estimated risk was evaluated on a four-point scale (no hazard, minor, serious, and critical). A total of 229 farmworkers were interviewed about field conditions.

RESULTS

Two out of the five camps did not have safe drinking water. Risks for farmworkers were lower when a manager was living on site. Field surveys estimated higher risk when provision of sanitation was deficient (P < 0.05). Farmworkers' responses concerning field conditions differed from the survey findings.

CONCLUSIONS

Risks for farmworkers depended largely on the environment provided. Discordances between survey results and farmworkers' interview responses suggested that self-reported data might have limited validity for this population. Working and living conditions require improvement to decrease occupational risks for farmworkers.

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.