Agriculture Health Study

The Main Agricultural Health Study - A Prospective Study of Cancer and Other Diseases Among Men and Women in Agriculture

The "Agricultural Health Study" (AHS) is a collaborative effort between the National Cancer Institute and the National Institute of Environmental Health Sciences. The U.S. Environmental Protection Agency and the National Institute for Occupational Safety and Health are providing support for a limited exposure assessment effort.

Initial data collection on a prospective cohort of 89,658 study subjects has been completed as of December 1997. Participants completed questionnaires that included items on pesticides used, other agricultural exposures, and work practices that modify exposure as well as on 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 of the study (1998-2003) updated information on occupational exposures, diet, work practices and medical history by means of a computer assisted telephone interview. We also collected buccal cells on sample of 34,000 study participants to assess the effect of inheritable polymorphisms and the interaction of environment and genomic predisposition.

The stimulus for this prospective investigation comes from the growing evidence that, despite a low mortality overall, farmers experience an excess of several cancers. These excesses have been observed in retrospective epidemiological studies among agricultural workers in several countries. Excess cancers are observed for the lymphatic and hematopoietic system, connective tissue, skin, brain, prostate, stomach and lips. Several of these tumors (brain, NHL, multiple myeloma, and prostate) are also increasing in the general population in many of these countries. This suggests a common set of exposures may explain the high rates in farmers and rising rates in the general population.

Farmers, their families, and other pest control workers may have contact with a variety of potentially hazardous substances including pesticides, solvents, fuels and oils, engine exhaust, dust and zoonotic viruses and other microbes. Our cohort study includes all registered pesticide applicators in Iowa and North Carolina and the spouse of applicators who are farmers. The health effects of pesticide use are the primary focus of the study. The influence of other farm exposures are also being evaluated.

The focus of the phase II follow-up period (2004-2008) is to update exposure information and health histories by means of a computer assisted interview and also following the cohort to determine disease incidence and mortality. The cohort is being followed through the cancer registries within Iowa and North Carolina, the Social Security Administration database, state vital statistics offices, National Death Index, and various in-state databases, such as the listing of registered pesticide applicators. Individuals who enrolled into the study but who are no longer at the address given during enrollment (based on subsequent attempts at follow up) have been submitted and will continue to be submitted (through NIOSH) in the standard format to the IRS under their Project 057 Taxpayer Address Request Program. Identifying data provided to the IRS include only SSN and the first four letters of last name of cohort member. IRS provides in return the most current address in IRS records if a match (SSN + all four letter of last name) is found. The purpose of this effort is to identify members of the cohort who have moved out of state, to enable adjustment of person-years for incidence and mortality calculations. Persons who have moved out of state can be followed for vital status and cause of death, but not for cancer incidence.

Continuation of the protocol will provide a valuable epidemiologic resource to help prevent cancers in the future by identifying risk factors in the rural/agricultural environment. Because more cases of important cancer outcomes occur in this cohort every year, potential cancer causes can be evaluated with increased statistical power. Larger number of cases also allows for statistical control of confounding factors, making more meaningful conclusions about cancer risk, and, for some relatively infrequent cancers, such as the lyphomas and leukemias, greater follow-up time is necessary to make any meaningful observations.

Study Overview

• Status: Active, not recruiting
• Conditions: Lymphoma; Multiple Myeloma; Prostate Cancer; Pesticide Exposures

Detailed Description

The "Agricultural Health Study" (AHS) is a collaborative effort between the National Cancer Institute and the National Institute of Environmental Health Sciences. The U.S. Environmental Protection Agency and the National Institute for Occupational Safety and Health are providing support for a limited exposure assessment effort. Initial data collection on a prospective cohort of 89,655 study subjects has been completed as of December 1997. Participants completed questionnaires that included items on pesticides used, other agricultural exposures, and work practices that modify exposure as well as on 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 of the study (1998-2003) updated information on occupational exposures, diet, work practices and medical history by means of a computer assisted telephone interview. We also collected buccal cells on sample of 34,000 study participants to assess the effect of inheritable polymorphisms and the interaction of environment and genomic predisposition. The stimulus for this prospective investigation comes from the growing evidence that, despite a low mortality overall, farmers experience an excess of several cancers. These excesses have been observed in retrospective epidemiological studies among agricultural workers in several countries. Excess cancers are observed for the lymphatic and hematopoietic system, connective tissue, skin, brain, prostate, stomach and lips. Several of these tumors (brain, NHL, multiple myeloma, and prostate) are also increasing in the general population in many of these countries. This suggests a common set of exposures may explain the high rates in farmers and rising rates in the general population.

Farmers, their families, and other pest control workers may have contact with a variety of potentially hazardous substances including pesticides, solvents, fuels and oils, engine exhaust, dust and zoonotic viruses and other microbes. Our cohort study includes all registered pesticide applicators in Iowa and North Carolina and the spouse of applicators who are farmers. The health effects of pesticide use are the primary focus of the study. The influence of other farm exposures are also being evaluated.

• Study Type: Observational
• Enrollment (Actual): 89655

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Research Triangle Park, North Carolina, United States, 27709
      • Research Triangle Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

A prospective cohort of 89,655 registered pesticide applicators and spouses (57,310 applicators and 32,346 spouses of private applicators) with sufficient personal identifiers to conduct follow up activities has been assembled during the first four years of recruitment in the Agricultural Health Study, 1993-1997. The majority of applicators were asked to enroll in the AHS as they obtained or renewed their pesticide registration/licenses through the agricultural extension services of the states of North Carolina and Iowa. In the last year of enrollment, applicators who received or renewed their pesticide licenses, but were never given the opportunity to enroll due to added requirements in the testing/training class, were called and asked to complete the enrollment questionnaire over the phone. Spouses of the private applicators were also given the opportunity to enroll via the telephone.

Description

• INCLUSION CRITERIA:

All registered pesticide applicators in Iowa and North Carolina and the spouse and children of applicators who are farmers.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Cohort of Agricultural Workers

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Non-cancer disease incidence in pesticide applicators	Evaluate non-cancer health risks associated with exposure to pesticides and other potential agricultural exposures, e.g., neurotoxicity, reproductive hazards, asthma and other respiratory diseases or symptoms, immunological toxicity, kidney disease, birth outcomes, and growth and development among offspring.	Follow-up was every 5 years (to date); now to be every 3-5 years (CMS linkage)
measurement of pesticide and other agricultural exposures	Assess agricultural exposures using periodic interviews and environmental and biological monitoring	Follow-up was every 5 years (to date)
Disease risk and dietary exposures	Identify and quantify cancer and other disease risks associated with dietary exposures and cooking practices and chemicals resulting from the cooking process.	Baseline and first follow-up only
Disease in spouses and children of farmers	Evaluate the disease risks among spouses and children of farmers that may arise from indirect contact with agricultural chemicals (e.g., ambient air drifts, pesticide residues on rugs, furniture, and other items, transferring chemicals) and nonoccupational exposures (e.g., applications to pets, in homes, and on gardens).	Cancer as annual; now semi annual; other diseases, about 3-5 years
Cancer incidence in pesticide applicators	Identify and quantify cancer risks among men and women, whites, and minorities associated with specific direct pesticide exposures and exposures to other agricultural agents.	Was annual; now semi annually (cancer linkages)
Agricultural exposures and biomarkers of exposure, biological effect, and biomarkers of pre-clinical disease and genetic susceptibility factors	Study the relationship between agricultural exposures, the occurrence of biomarkers of exposure, biological effect, and biomarkers of pre-clinical disease and genetic susceptibility factors relevant to carcinogenesis.	Follow-up was every 5 years (to date); now to be every 3-5 years (CMS linkage)

Collaborators and Investigators

• Sponsor: National Cancer Institute (NCI)
• Collaborators: Environmental Protection Agency (EPA)
• Investigators: Principal Investigator: Laura Beane Freeman, Ph.D., National Cancer Institute (NCI)

Publications and helpful links

General Publications

• Alavanja MC, Blair A, Merkle S, Teske J, Eaton B. Mortality among agricultural extension agents. Am J Ind Med. 1988;14(2):167-76. doi: 10.1002/ajim.4700140207.
• Barthel E. Increased risk of lung cancer in pesticide-exposed male agricultural workers. J Toxicol Environ Health. 1981 Nov-Dec;8(5-6):1027-40. doi: 10.1080/15287398109530135.
• Bjeldanes LF, Morris MM, Timourian H, Hatch FT. Effects of meat composition and cooking conditions on mutagen formation in fried ground beef. J Agric Food Chem. 1983 Jan-Feb;31(1):18-21. doi: 10.1021/jf00115a005. No abstract available.
• Lebov JF, Engel LS, Richardson D, Hogan SL, Hoppin JA, Sandler DP. Pesticide use and risk of end-stage renal disease among licensed pesticide applicators in the Agricultural Health Study. Occup Environ Med. 2016 Jan;73(1):3-12. doi: 10.1136/oemed-2014-102615. Epub 2015 Jul 15.

Study record dates

Study Major Dates

• Study Start: April 30, 1993

Study Registration Dates

• First Submitted: July 14, 2006
• First Submitted That Met QC Criteria: July 14, 2006
• First Posted (Estimated): July 17, 2006

Study Record Updates

• Last Update Posted (Actual): May 6, 2024
• Last Update Submitted That Met QC Criteria: May 3, 2024
• Last Verified: October 2, 2023

More Information

Terms related to this study

• Keywords: Cancer; Natural History; Pesticides; Agriculture
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Immune System Diseases; Neoplasms by Histologic Type; Neoplasms; Lymphoproliferative Disorders; Immunoproliferative Disorders; Hematologic Diseases; Hemorrhagic Disorders; Hemostatic Disorders; Paraproteinemias; Blood Protein Disorders; Neoplasms, Plasma Cell; Multiple Myeloma
• Other Study ID Numbers: 999993013; OH93-NC-N013

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No