AsthmaNCT01399411
Agricultural Health Study Follow-up
An observational study of Asthma and Parkinson's Disease, run by National Institute of Environmental Health Sciences (NIEHS) at 3 sites in United States.
Trial summary
Background: The Agricultural Health Study (AHS) is looking at the long-term health effects of farming exposures including pesticides, crops, and animals. The chronic health effects of exposure to pesticides are easier to study in farmers and their spouses. Read more about this study
- Who is it for?
- Ages 24 years and older
- Conditions the study is for
- Asthma, Parkinson's Disease
- How many people
- 89,656 participants
- Where
- 3 sitesUnited States
- Study dates
- 5 Jul 2011to not given
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 24 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Current Agricultural Health Study (AHS) participants (licensed pesticide applicators and their spouses from Iowa and North Carolina)
Who may be able to join
- All members of the AHS cohort who were eligible for the Phase 3 interview were eligible for the Phase 4 health follow-up. We will apply the same eligibility criteria for future cohort-wide follow-ups. Individuals who only completed the enrollment questionnaire were excluded from Phase 3 eligibility. Depending upon the disease outcome of interest, we may conduct the disease confirmation and validation efforts under this protocol among all participants in the AHS who provided self-reported diagnoses at any interview (e.g. Baseline, or Phases 2-4). For individuals who are unable to participate, we will allow a proxy to provide the information.
- For the validation efforts, individuals who do not confirm their diagnosis of interest (via self or proxy report) will not be asked to provide physician contact for medical records. For specimen collection, we will ask the proxy respondent about whether the individual would be able to provide a sample. In order to obtain MRR we will allow the participant or their medical proxy to sign the form. For cases who are cognitively impaired or deceased, a medical proxy will be identified.
- Determination of cognitive impairment will be made by report of proxy or by interviewer during conversation with participant. Because the AHS enrolled husband - wife pairs, we should be able to identify an appropriate proxy for most participants.
Who cannot join
None listed.
Trial locations and contacts
3 sites in 1 country.
United States3 sites
Batelle, Inc.
Columbus, Ohio, 43201
University of Iowa
Iowa City, Illinois, 52242
NIEHS, Research Triangle Park
Research Triangle Park, North Carolina, 27709
About this study
Official title: Agricultural Health Study: Health Followup
Background:
- The Agricultural Health Study (AHS) is looking at the long-term health effects of farming exposures including pesticides, crops, and animals. The chronic health effects of exposure to pesticides are easier to study in farmers and their spouses. They know what chemicals they use and tend to live in the same place for most of their adult lives. AHS participants are expected to report any changes in their health. This includes any new medical conditions. Researchers want to follow up on these reports to confirm their accuracy.
Read more
Objectives:
- To follow up AHS participants who have self-reported that they have a new disease and confirm their diagnosis.
Eligibility:
- Current AHS participants.
Design:
- Researchers will confirm self-reported changes in medical conditions by contacting the AHS participant to ask for more information.
- The AHS participant will give permission for researchers to contact their doctor to look at their medical records. They will also be asked to provide a cheek swab or saliva sample.
- Diseases of interest are rheumatoid arthritis, lupus, and Sjogren s Syndrome. Other diseases will be followed up in the future. Other diseases will be followed up in the future.
Read the detailed description
Pesticides are a common environmental exposure due to their widespread use for agricultural, residential, and public health purposes. Farmers and their families represent a unique population for studying the chronic health effects of pesticides because farmers know what chemicals they use, furthermore, farmers tend to remain at the same location over most of their adult life. The Agricultural Health Study (AHS), a cohort of approximately 89,000 pesticide applicators and spouses from Iowa and North Carolina, is the largest US cohort study of individuals working with pesticides. The AHS cohort was enrolled in 1993 to 1997 to assess human health effects associated with well-characterized exposures to pesticides and other agricultural factors. Detailed exposure data were collected at enrollment and in two five-year follow-up interviews. As a result, the AHS has a wealth of information on pesticide use by both farmers and their spouses, as well as the ability to account for changes in pesticide use over time. Information on medical history and important covariates was also collected at enrollment and in the follow-up interviews, and will continue to be collected over time.Only mortality and cancer incidence are updated annually through linkage to vital statistics and cancer registries; all other health outcomes are based on self-reported information from participants.The accuracy of self-reported health outcome information can vary from quite good (e.g., asthma) to poor (e.g., rheumatoid arthritis). In order to ensure high quality epidemiologic analyses, validation of self-reported disease is necessary prior to statistical analysis. To date, several health endpoints have been validated through follow-up with AHS participants and their physicians. The purpose of the current protocol is three-fold: 1) update information on medical history and other important covariates through ongoing follow-up interviews of the cohort; 2) validate self-reported diseases among cohort participants over the duration of cohort follow-up (at least through 2020); and 3) complete initial contact of potential participants to inform them of other health outcome studies being conducted within the cohort by an outside institution.
We will contact AHS cohort members to complete a follow-up interview allowing one of three modes of response: self-administered paper questionnaire, self-administered web survey (CAWI), and interviewer-administered telephone interview (CATI). We will contact proxy respondents if the participant is unable to provide information.
We will validate a variety of diseases of interest as they are ascertained in the cohort. While the characteristics of the diseases may vary, the strategy for disease validation is similar to the cohort wide follow-up. Validation efforts may also include a request for permission to contact the participant s physician, and contacting the physician s office to obtain the relevant medical information. We will contact proxy respondents if the participant is unable to provide information.
- Conditions
- Asthma, Parkinson's Disease
- Keywords
- Self-Reported, Farming, Agriculture, Disease Validation, Autoimmune Disorders, Natural History
- Medical subject headings
- Asthma, Parkinson Disease, Autoimmune Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| AHS Cohort | licensed pesticide applicators and their spouses from Iowa and North Carolina already enrolled in the Agricultural Health Study (AHS) |
What is being measured
The primary outcome is the main question the study is designed to answer.
The purpose of the current protocol is three-fold: 1) update information on medical history and other important covariates through ongoing follow-up interviews of the cohort; 2) validate self-reported diseases among cohort participants over the ...
Changes in health over time.
Measured: Various phases of follow-up; diseases are validated as they are ascertained
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2011 (estimated)
- Study start5 Jul 2011
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AsthmaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 89,656 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Institute of Environmental Health Sciences (NIEHS)
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Dale P Sandler, Ph.D., Principal investigator, National Institute of Environmental Health Sciences (NIEHS)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01399411
- Sponsor's protocol ID
- 999911196
- Other IDs
- 11-E-N196
- Status last verified
- 17 Aug 2026
- First submitted
- 20 Jul 2011
- Last updated
- 5 Nov 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 5 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Agricultural Health Study: Health Followup
- ClinicalTrials.gov ID
- NCT01399411
- Acronym / sponsor ID
- 999911196
- Conditions
- Asthma, Parkinson's Disease
- Keywords
- Self-Reported, Farming, Agriculture, Disease Validation, Autoimmune Disorders, Natural History
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 89,656 participants (actual)
- Lead sponsor
- National Institute of Environmental Health Sciences (NIEHS)US National Institutes of Health
- Study start
- 5 Jul 2011 (actual)
- First posted
- 21 Jul 2011 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Background:
- The Agricultural Health Study (AHS) is looking at the long-term health effects of farming exposures including pesticides, crops, and animals. The chronic health effects of exposure to pesticides are easier to study in farmers and their spouses. They know what chemicals they use and tend to live in the same place for most of their adult lives. AHS participants are expected to report any changes in their health. This includes any new medical conditions. Researchers want to follow up on these reports to confirm their accuracy.
Objectives:
- To follow up AHS participants who have self-reported that they have a new disease and confirm their diagnosis.
Eligibility:
- Current AHS participants.
Design:
- Researchers will confirm self-reported changes in medical conditions by contacting the AHS participant to ask for more information.
- The AHS participant will give permission for researchers to contact their doctor to look at their medical records. They will also be asked to provide a cheek swab or saliva sample.
- Diseases of interest are rheumatoid arthritis, lupus, and Sjogren s Syndrome. Other diseases will be followed up in the future. Other diseases will be followed up in the future.
Detailed description
Pesticides are a common environmental exposure due to their widespread use for agricultural, residential, and public health purposes. Farmers and their families represent a unique population for studying the chronic health effects of pesticides because farmers know what chemicals they use, furthermore, farmers tend to remain at the same location over most of their adult life. The Agricultural Health Study (AHS), a cohort of approximately 89,000 pesticide applicators and spouses from Iowa and North Carolina, is the largest US cohort study of individuals working with pesticides. The AHS cohort was enrolled in 1993 to 1997 to assess human health effects associated with well-characterized exposures to pesticides and other agricultural factors. Detailed exposure data were collected at enrollment and in two five-year follow-up interviews. As a result, the AHS has a wealth of information on pesticide use by both farmers and their spouses, as well as the ability to account for changes in pesticide use over time. Information on medical history and important covariates was also collected at enrollment and in the follow-up interviews, and will continue to be collected over time.Only mortality and cancer incidence are updated annually through linkage to vital statistics and cancer registries; all other health outcomes are based on self-reported information from participants.The accuracy of self-reported health outcome information can vary from quite good (e.g., asthma) to poor (e.g., rheumatoid arthritis). In order to ensure high quality epidemiologic analyses, validation of self-reported disease is necessary prior to statistical analysis. To date, several health endpoints have been validated through follow-up with AHS participants and their physicians. The purpose of the current protocol is three-fold: 1) update information on medical history and other important covariates through ongoing follow-up interviews of the cohort; 2) validate self-reported diseases among cohort participants over the duration of cohort follow-up (at least through 2020); and 3) complete initial contact of potential participants to inform them of other health outcome studies being conducted within the cohort by an outside institution.
We will contact AHS cohort members to complete a follow-up interview allowing one of three modes of response: self-administered paper questionnaire, self-administered web survey (CAWI), and interviewer-administered telephone interview (CATI). We will contact proxy respondents if the participant is unable to provide information.
We will validate a variety of diseases of interest as they are ascertained in the cohort. While the characteristics of the diseases may vary, the strategy for disease validation is similar to the cohort wide follow-up. Validation efforts may also include a request for permission to contact the participant s physician, and contacting the physician s office to obtain the relevant medical information. We will contact proxy respondents if the participant is unable to provide information.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| AHS Cohort | – | –licensed pesticide applicators and their spouses from Iowa and North Carolina already enrolled in the Agricultural Health Study (AHS) |
Who may qualify
- Ages
- 24 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Current Agricultural Health Study (AHS) participants (licensed pesticide applicators and their spouses from Iowa and North Carolina)
Key inclusion criteria (3 listed)
- All members of the AHS cohort who were eligible for the Phase 3 interview were eligible for the Phase 4 health follow-up. We will apply the same eligibility criteria for future cohort-wide follow-ups. Individuals who only completed the enrollment questionnaire were excluded from Phase 3 eligibility. Depending upon the disease outcome of interest, we may conduct the disease confirmation and validation efforts under this protocol among all participants in the AHS who provided self-reported diagnoses at any interview (e.g. Baseline, or Phases 2-4). For individuals who are unable to participate, we will allow a proxy to provide the information.
- For the validation efforts, individuals who do not confirm their diagnosis of interest (via self or proxy report) will not be asked to provide physician contact for medical records. For specimen collection, we will ask the proxy respondent about whether the individual would be able to provide a sample. In order to obtain MRR we will allow the participant or their medical proxy to sign the form. For cases who are cognitively impaired or deceased, a medical proxy will be identified.
- Determination of cognitive impairment will be made by report of proxy or by interviewer during conversation with participant. Because the AHS enrolled husband - wife pairs, we should be able to identify an appropriate proxy for most participants.
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
The purpose of the current protocol is three-fold: 1) update information on medical history and other important covariates through ongoing follow-up interviews of the cohort; 2) validate self-reported diseases among cohort participants over the ...
Time frame: Various phases of follow-up; diseases are validated as they are ascertained
Changes in health over time.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Nov 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Dale P Sandler, Ph.D. principal investigator
National Institute of Environmental Health Sciences (NIEHS)
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Asthma and Parkinson's Disease, run by National Institute of Environmental Health Sciences (NIEHS) at 3 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The purpose of the current protocol is three-fold: 1) update information on medical history and other important covariates through ongoing follow-up interviews of the cohort; 2) validate self-reported diseases among cohort participants over the ... (time frame: Various phases of follow-up; diseases are validated as they are ascertained). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.