Farm Family Exposure Study: methods and recruitment practices for a biomonitoring study of pesticide exposure BETH A. BAKER, a BRUCE H. ALEXANDER, b JACK S. MANDEL, c JOHN F. ACQUAVELLA, d RICHARD HONEYCUTT e AND PAMELA CHAPMAN f a Regions Hospital, St Paul, Minnesota, USA b School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA c Rollins School of Public Health, Emory University, Atlanta, Georgia, USA d Monsanto Company, St Louis, Missouri, USA e H.E.R.A.C, Columbia, South Carolina, USA f ChemRisk, San Francisco, California, USA Purpose: The Farm Family Exposure Study was initiated to characterize pesticide exposure to farm family members around the time of one pesticide application in a manner that will facilitate exposure assessment in epidemiologic studies of pesticides. Methods: A sample of farm families with children was recruited by randomly selecting farmers from lists of licensed pesticide applicators in Minnesota and South Carolina. Eligible families were selected from among those who planned to apply one of three chemicals, glyphosate, 2,4-D, or chlorpyrifos, as part of their normal operations. The applicator, spouse, and all children in the family ages 4–17 years were included in the study. The applicator and spouse completed self-administered questionnaires addressing demographics, farming practices and potential exposures to them and their children. Field observers documented the application, recorded application practices, equipment, potential exposures, and the presence of children or spouses in the immediate vicinity of pesticide activities. All study participants were asked to collect each urine void for 5 days, 1 day before through 3 days after the application. Pesticides were measured in 24-h composite urine samples with a one part per billion limit of detection. Results: Of 11,164 applicators screened, 994 families met the inclusion criteria. Of these, 95 families were enrolled. Enrollees were similar in most characteristics to their peers who were not participants in the study. In total, there were 106 applications, 10 of which involved more than one chemical. This resulted in urinary data for 48 farmers and spouses and their 79 children for glyphosate, 34 farmers and spouses and their 50 children for chlorpyrifos, and 34 farmers and spouses and their 53 children for 2,4-D. Compliance with the 24-h urine collection was particularly good for the adult participants. There were more missing samples for children than for adults, but overall compliance was high. Conclusion: The Farm Family Exposure Study should provide insights about pesticide exposure under real world conditions and thereby facilitate improved exposure assessment in epidemiologic studies of agricultural populations. Journal of Exposure Analysis and Environmental Epidemiology (2005) 15, 491–499. doi:10.1038/sj.jea.7500427; published online 18 May 2005 Keywords: pesticide exposure glyphosate, biomonitoring chlorpyrifos, urine pesticides 2;4-D. Introduction Characterizing exposure is one of the greatest challenges in the study of how adverse health outcomes may be related to pesticides (Blair and Zahm, 1990a,b, 1995; Morrison et al., 1992; Dich et al., 1997; Fleming and Herzstein, 1997; Zahm and Ward, 1998). Epidemiological studies have largely focused on agricultural populations because the likelihood of appreciable pesticide exposure is greater than for nonfarming populations. Agricultural-related exposure to pesticides can occur from both occupational and nonoccupa- tional sources. Farm family members and farm workers may be exposed directly through application through secondary routes such as contaminated clothing, household surfaces, footwear and drift from a pesticide application. Nonoccupa- tional pesticide exposure in children may occur from working or playing in fields following an application, drift from agricultural use, or through the use of pesticides in gardens, homes or on lawns. Epidemiologic studies have associated several health effects with subacute pesticide exposure, including cancer, repro- ductive outcomes, immunologic effects, endocrine disruption, and neurologic effects (Weisenburger, 1993; Savitz et al., 1994; Kavlock et al., 1996; Fleming and Herzstein, 1997), but the results have not been consistent. Overall cancer incidence and mortality for farmers or agricultural workers is generally lower than for the general population (Pearce and Reif, 1990; Maroni and Fait, 1993; Blair and Zahm, 1995; Received 9 June 2004; accepted 5 March 2005; published online 18 May 2005 1. Address all correspondence to: Dr. Bruce H. Alexander, Division of Environmental Health Sciences, School of Public Health, University of Minnesota, MMC 807 Mayo Building, 420 Delaware Street S.E., Minneapolis, MN 55455, USA. Tel: þ 16126257934. E-mail: balex@umn.edu Journal of Exposure Analysis and Environmental Epidemiology (2005) 15, 491–499 r 2005 Nature Publishing Group All rights reserved 1053-4245/05/$30.00 www.nature.com/jea