The Agricultural Health Study (AHS) is a prospective study of licensed pesticide applicators from North Carolina and Iowa recruited in 1993-1997 at the time of license renewal. The cohort includes 4,916 commercial applicators from Iowa and 52,395 private applicators, mostly farmers, from both states. More than 75% or 32,347 spouses of married private applicators also enrolled in the cohort. The study is a collaboration of the National Institute of Environmental Health Sciences (NIEHS), the National Cancer Institute (NCI), the Environmental Protection Agency (EPA) and the National Institute for Occupational Safety and Health (NIOSH).
Applicators completed a short enrollment questionnaire on farming, personal pesticide use and lifestyle factors. Applicators who completed the questionnaire received a set of take-home questionnaires, including two to be completed by the female spouse of farmers and a third to be completed by the applicator that obtained additional details on pesticide exposure and health status. During 1999 – 2003 a follow-up telephone interview updated exposure information and changes in health status. Participants who completed the interview were asked to provide a buccal-cell DNA sample—for future analyses of gene and environment interactions—and a food frequency questionnaire by mail. Follow-up data have been collected in two subsequent rounds of questionnaires through 2014 and active follow-up is ongoing to identify new disease diagnoses and update key covariates.
Questionnaires provided self-reported information on demographic factors, medical characteristics, history of smoking and alcohol use, and a lifetime history of pesticide use, including 50 specific compounds. Over 68% of applicators (33,450) and 75% of spouses (23,775) completed the first follow-up interview. Approximately 40% of participants returned buccal cell samples.
In addition to studying changes in health that are reported through the follow-up questionnaire, the researchers annually link the cohort to state cancer registries and vital records to monitor cancer incidence and mortality.
As an occupational group, farmers are unique in that they often live where they work and their family members often participate in farming activities and may have inadvertent exposure to potential farm hazards. The AHS is the largest study of farmers and their families in the world and has provided Epidemiology Branch investigators and collaborators with an invaluable source of information. The study collects comprehensive data on pesticide exposure and factors that might modify exposures and has developed and validated improved methods for pesticide exposure assessment. Information provided by spouses about their children has facilitated studies on the health of children who live on farms. Topics of specific interest to NIEHS investigators, trainees and collaborators include neurobehavioral function and neurodegenerative diseases, respiratory health, reproductive health, autoimmune disease, diabetes, kidney disease, thyroid disease, and cancer. Individuals interested in collaborating with the AHS should contact Christine Parks, Ph.D. to discuss opportunities.
- AHS African-American Farmers and Farmworkers - Morbidity and Mortality
- AHS Neurobehavioral Study
- Biomarkers of Exposure and Effects in Agriculture
- Farming and Movement Evaluation (FAME) Study—Nested case-control study of Parkinson's Disease
- Growth and Puberty Study (GAP)
- Neurological Outcomes Among Pesticide Applicators
- AHS Study of Memory and Aging
Dale Sandler, Ph.D.
Chief, Epidemiology Branch and Senior Investigator