Our understanding of the health risks of farmworkers exposed to pesticides in their work and home environments is rapidly increasing, although studies designed to examine the possible neurobehavioral effects of low-level chronic pesticide exposure are limited. We measured dialkyl phosphate urinary metabolite levels, collected environmental dust samples from a subset of homes, obtained information on work practices, and conducted neurobehavioral tests on a sample of farmworkers in Oregon. Significant correlations between urinary methyl metabolite levels and total methyl organophosphate (azinphos-methyl, phosmet, malathion) house dust levels were observed. We found the neurobehavioral performance of Hispanic immigrant farmworkers to be lower than that observed in a nonagricultural Hispanic immigrant population, and within the sample of agricultural workers there was a positive correlation between urinary organophosphate metabolite levels and poorer performance on some neurobehavioral tests. These findings add to an increasing body of evidence of the association between low levels of pesticide exposure and deficits in neurobehavioral performance.

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There are few data on pesticide exposures of migrant Latino farmworker children, and access to this vulnerable population is often difficult. In this paper we describe a community-based approach to implement culturally appropriate research methods with a migrant Latino farmworker community in Oregon. Assessments were conducted in 96 farmworker homes and 24 grower homes in two agricultural communities in Oregon. Measurements included surveys of pesticide use and work protection practices and analyses of home-dust samples for pesticide residues of major organophosphates used in area crops. Results indicate that migrant farmworker housing is diverse, and the amounts and types of pesticide residues found in homes differ. Azinphos-methyl (AZM) was the pesticide residue found most often in both farmworker and grower homes. The median level of AZM in farmworker homes was 1.45 ppm compared to 1.64 ppm in the entry area of grower homes. The median level of AZM in the play areas of grower homes was 0.71 ppm. The levels of AZM in migrant farmworker homes were most associated with the distance from fields and the number of agricultural workers in the home. Although the levels of AZM in growers and farmworker homes were comparable in certain areas, potential for disproportionate exposures occur in areas of the homes where children are most likely to play. The relationship between home resident density, levels of pesticide residues, and play behaviors of children merit further attention.

The purpose of this study was to determine whether long-term modulation of inflammatory activity by tumor necrosis factor (TNF)-α inhibitors has some influence on insulin resistance (IR). 16 active rheumatoid arthritis (RA) patients without CV risk factors treated with anti-TNF-α agents were included in this study. RA activity by disease activity score 28, IR by HOMA2-IR, body composition by impedance analysis, physical activity by accelerometry, abdominal fat distribution by magnetic resonance imaging, and serum level of key adipokines by ELISA were measured at baseline and during a 1-year follow-up period. Patient body mass index increased significantly (26.94 ± 3.88 vs. 28.06 ± 4.57 kg/m2, p=0.02) after 1 year of treatment. Body composition, in terms of fat and fat-free mass, remained unchanged except for a significant elevation in body cell mass (25.50 ± 4.60 vs. 26.60 ± 3.17 kg, p=0.02). Basal levels of IR in the RA patients included in this study were significantly higher than healthy controls (1.6 ± 0.8 vs. 1.11 ± 0.56, p=0.011) but did not change during the follow-up. Nor did basal concentrations of adiponectin, visfatin, leptin, ghrelin, resistin, and apelin in response to anti-TNF-α treatment; only retinol-binding protein 4, showed a significant increase (51.7 ± 32.7 vs. 64.9 ± 28.4 μg/ml, p=0.03) at the end of the study. IR, adiposity distribution, and serum levels of most adipokines are not significantly affected by long-term inhibition of TNF-α in RA patients. Our data suggest that although systemic blockade of TNF-α exerts an anticachectic effect in RA patients, it does not seem to play a major role in IR.

Children of migrant farmworkers are at increased risk of exposure to organophosphate pesticides because of “carry-home” transport processes and residential location. Although this at-risk status is generally recognized, few available reports describe the extent of this exposure among agricultural communities. We quantified dialkyl phosphate (DAP) levels in serial samples of urine from 176 children, 2–6 years of age, in three Oregon communities hosting differing agricultural industries: pears, cherries, and fruit berries. Up to three spot samples of urine were collected from children at the beginning, mid-point, and end of their parents’ work seasons. The median levels of dimethylthiophosphate (DMTP), the most commonly detected metabolite, was significantly higher in urine samples from children in each of the three agricultural communities (17.5, 19.0, and 41.0 ng/mL) relative to a reference group of children who lived in an urban community and whose parents did not work in agriculture (6.5 ng/mL; Kruskal-Wallis, p < 0.001). After controlling for age, sex, and weight, the median level of DMTP in children in the pear community was 1.92 times higher than the level in children of the berry community [95% confidence interval (CI), 1.14–3.23] and 1.75 times higher than the level in children of the cherry community (95% CI, 0.95–3.23). We observed increasing levels of DMTP across the work season only within the berry community. Levels decreased in the cherry community and remained constant in the pear community. Substantial temporal variation within the children followed demonstrates the need for multiple urine samples to most accurately characterize longer term and/or cumulative exposure. The observed variability in urinary DAP levels, between communities and over time, could be attributed to the types and amounts of organophosphate pesticides used, the timing of applications and degradation of residues in the environment, work operations and hygiene practices, the proximity of housing to orchards and fields, or the movement of these working families. Additional studies of variation in pesticide exposure across agricultural regions are needed.