Published in the Journal of Occupational Health Psychology, 2010, Vol. 15, No. 3, 252–266.
Joseph G. Grzywacz, Sara A. Quandt, Quirina M. Vallejos, Lara E. Whalley, Haiying Chen, and Scott Isom, Wake Forest University School of Medicine; Dana B. Barr, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA; Thomas A. Arcury, Wake Forest University School of Medicine.
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The goal of this study was to understand the potential threat of job stressors to farmworker health. To accomplish this goal we studied pesticide exposure, an issue with immediate and long-term health consequences, and predictions from the Demands-Control model of occupational stress. Longitudinal, self-report data and urine samples were collected at monthly intervals from a cohort of Latino farmworkers (N 287) during the 2007 agricultural season. The primary hypothesis was that greater exposure to psychological demands, physical exertion, and hazardous work conditions are associated with greater odds of detecting dialkylphosphate (DAP) urinary pesticide metabolites, biomarkers indicating exposure to pesticides. Contrary to this hypothesis, results indicated that none of the elements of the Demands-Control model were independently associated with detection of DAP urinary pesticide metabolites. However, analyses produced several interaction effects, including evidence that high levels of control may buffer the effects of physical job demands on detection of DAP urinary pesticide metabolites.
Farmworkers, the vast majority of whom are immigrants from Mexico and Central America, constitute a population at risk for excess morbidity and mortality, including elevated occupational injury and illness (Arcury & Quandt, 2007; Villarejo, 2003).
These health problems arise from and are exacerbated by a variety of physical and psychological stressors inherent in employment in a dangerous industry, social isolation, and discrimination. Although they confront a variety of stressors in their daily lives on the job, few studies of immigrant Latino farmworkers examine the potential effect of stressors on general indicators of physical health (Grzywacz, Quandt, & Arcury, 2008) or specific health threats, such as pesticide exposure. Thus, the role that job stress plays in the health, illness, and subsequent health disparities confronted by the very workers whose toils bring food to the American table remains unknown.
The goal of this study was to elucidate the potential threat of job stressors to farmworker health. We focus specifically on pesticide exposure, an issue with immediate and long-term health consequences for farmworkers and their families. Informed by Demands-Control theory of occupational stress (Karasek & Theorell, 1990), we differentiated between psychological and physical job demands and hypothesized that (1) greater exposure to psychological demands, heightened physical exertion, and hazardous work conditions are associated with greater pesticide exposure, as indicated by the presence of urinary dialkylphosphate (DAP) metabolites of organophosphorus (OP) pesticides; and (2) the effects of psychological demands, physical exertion, and hazardous work conditions on detection of DAP urinary metabolites is greater for workers with low levels of control. We also explored the possibility of double-demand and asked if the deleterious effects of physical exertion and hazardous conditions are exacerbated by elevated psychological demands.