Orientation Document

Orientation Document
	Executive Committee
	Study and Cohort Descriptions
	Ongoing Substudies
	Publications
	AHS Support

Study and Cohort Descriptions

The Agricultural Health Study is a collaborative effort involving the National Cancer Institute (NCI), the National Institute of Environmental Health Sciences (NIEHS), and the U.S. Environmental Protection Agency (EPA). The study has four major components:

1. The main prospective cohort study - cancer and non-cancer outcomes
1. linkage with cancer registries, vital statistics, United States Renal Data System (USRDS)
2. ongoing data collection (i.e., telephone interview, food frequency questionnaire and cheek cell collection
2. Cross-sectional studies -- including questionnaire data, functional measures, biomarkers, and GIS
3. Nested case-control studies
4. Exposure assessment and validation studies.

The cohort includes 89,656 private pesticide applicators, spouses of private applicators, and commercial pesticide applicators recruited within Iowa and North Carolina (Table 1). Phase I, initial cohort recruitment, began in 1993 and concluded in 1997. Phase II follow up began in 1999 and concluded for private applicators and spouses in 2003. Phase II follow up of commercial applicators started in October 2003 and concluded in October 2005. The Phase III follow up began in November 2005 and concluded in February 2010.

Phase I observation involved administration of a questionnaire to obtain information on pesticide use, other agricultural exposures, work practices that modify exposures, and other activities that may affect either exposure or disease risks (e.g., diet, exercise, alcohol consumption, medical conditions, family history of cancer, other occupations, and smoking history). Phase II had three data collection components: a computer assisted telephone interview (CATI), buccal cell collection, and a mailed dietary questionnaire. Phase II interviews are designed to record updated information on pesticide use since enrollment, current farming and work practices, and changes in health status. In addition, the Dietary Health Questionnaire in Phase II makes a detailed evaluation of subjects' cooking practices and dietary intake. The buccal cell collection of Phase II was implemented to assess the impact of genetic risk factors on epidemiologic outcomes. Phase II had data collection included a computer assisted telephone interview (CATI) and buccal cell collection.

Phase II and Phase III interviews were designed to record updated information on pesticide use since enrollment, current farming and work practices, and changes in health status. In addition to Phase II and Phase III data collection activities that include the whole cohort, a series of sub-studies involving a small number of study participants directly measured applicator and family member exposures to selected pesticides. Some sub-studies have focused in greater detail on subgroups with specific diseases or exposures.

¹Progress through May 2011