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Data on recent and historic pesticide use, pesticide application methods, and farm characteristics were collected from 35,879 restricted-use pesticide applicators in the first 2 years of the Agricultural Health Study, a prospective study of a large cohort of private and commercial licensed pesticide applicators that is being conducted in Iowa and North Carolina. (In Iowa, applicators are actually "certified," while in North Carolina they are "licensed"; for ease of reference the term license will be used for both states in this paper.) Commercial applicators (studied in Iowa only) apply pesticides more days per year than private applicators in either state. When the types of pesticides being used by different groups are compared using the Spearman coefficient of determination (r2), we find that Iowa private and Iowa commercial applicators tend to use the same type of pesticides (r2=0.88). White and nonwhite private applicators tended to use the same type of pesticides (North Carolina r2=0.89), as did male and female private applicators (Iowa r2=0.85 and North Carolina r2=0.84). There was less similarity (r2=0. 50) between the types of pesticides being used by Iowa and North Carolina private applicators. A greater portion of Iowa private applicators use personal protective equipment than do North Carolina private applicators, and pesticide application methods varied by state. This heterogeneity in potential exposures to pesticides between states should be useful for subsequent epidemiologic analyses using internal comparison groups., (Copyright 1999 Academic Press.)

To investigate factors associated with pesticide-related visits to health care providers (i.e., doctor or hospital visits), responses to self-administered questionnaires received from 35,879 licensed restricted-use pesticide applicators participating in the Agricultural Health Study were analyzed. (In Iowa, applicators are actually certified, whereas in North Carolina they are licensed; for ease of reference, the term license will be used for both states in this paper.) The cohort reported a total of more than 10.9 million pesticide-application days. These applications were associated with one or more pesticide-related health care visits by 2,214 applicators (7.0% of the applicator cohort for whom health care visit data were available). The odds of a pesticide-related health care visit were increased for commercial applicators compared to private applicators [odds ratio (OR = 1.77; 95% confidence interval (CI), 1.52-2.06) and for applicators who used insecticides 70 times or more in their lifetime compared to those who used insecticides less frequently (OR = 1.43; CI, 1.26-1.63). After adjusting for the number of applications in a logistic regression model, significantly higher odds of health care visits were observed among North Carolina applicators compared to Iowa applicators (OR = 1.35; CI, 1.17-1.52), among applicators who mixed their own pesticides (OR = 1.65; CI, 1. 22-2.23), and among applicators who personally repaired their pesticide application equipment at least once per year (OR = 1.12; CI, 1.06-1.25). Significantly lower odds were found among female versus male applicators (OR = 0.68; CI, 0.46-0.99) and among applicators who graduated from high school versus those who did not (OR = 0.82; CI, 0.71-0.94 for high school graduates and OR = 0.79; CI, 0.68-0.91 for those with at least some college). Several methods of pesticide application to crops, seed, or stored grain were also associated with significantly elevated odds ratios of health care visits. These observations suggest that several steps can be taken to reduce the number of health care visits resulting from occupational exposure to pesticides. The implications of this pattern of pesticide-related health care visits may have etiologic implications for cancer and other chronic diseases.

The Agricultural Health Study, a large prospective cohort study has been initiated in North Carolina and Iowa. The objectives of this study are to: 1) identify and quantify cancer risks among men, women, whites, and minorities associated with direct exposure to pesticides and other agricultural agents; 2) evaluate noncancer health risks including neurotoxicity reproductive effects, immunologic effects, nonmalignant respiratory disease, kidney disease, and growth and development among children; 3) evaluate disease risks among spouses and children of farmers that may arise from direct contact with pesticides and agricultural chemicals used in the home lawns and gardens, and from indirect contact, such as spray drift, laundering work clothes, or contaminated food or water; 4) assess current and past occupational and nonoccupational agricultural exposures using periodic interviews and environmental and biologic monitoring; 5) study the relationship between agricultural exposures, biomarkers of exposure, biologic effect, and genetic susceptibility factors relevant to carcinogenesis; and 6) identify and quantify cancer and other disease risks associated with lifestyle factors such as diet, cooking practices, physical activity, smoking and alcohol consumption, and hair dye use. In the first year of a 3-year enrollment period, 26,235 people have been enrolled in the study, including 19,776 registered pesticide applicators and 6,459 spouses of registered farmer applicators. It is estimated that when the total cohort is assembled in 1997 it will include approximately 75,000 adult study subjects. Farmers, the largest group of registered pesticide applicators comprise 77% of the target population enrolled in the study. This experience compares favorably with enrollment rates of previous prospective studies.