Early Life Exposures in Agriculture
Condition: Testicular Cancer; Leukemia; Lymphoma; Brain Cancer
MeSH terms: Brain Neoplasms; Testicular Neoplasms
Study type: Observational

Summary: 
      Background:

      The Agricultural Health Study (AHS) studied farmers and their spouses in North Carolina and
      Iowa. It also included people who worked with pesticides in Iowa. They answered a
      questionnaire and gave data about their children born since 1975. Researchers want to link
      this data to public data like birth and death certificates. They want to study how early life
      exposures to farms are linked to cancer and other bad health outcomes.

      Objective:

      To study data to find links between early life farm exposure and negative health outcomes.

      Eligibility:

      There will be no human subjects.

      Design:

      Researchers will get public data in the two study states. This will come from things like:

      Birth certificates

      Driver s licenses

      Voter registration

      Death certificates

      Based on these plus the AHS data, they will create a study group. It will be called Early
      Life Exposure in Agriculture (ELEA).

      Researchers will link ELEA data to cancer data. This will identify prevalence of cancer.

      They will study parents answers on the AHS. The topics include farm practices and pesticide
      use. They will determine ELEA exposure to pesticides.

      Researchers will analyze the cancer and pesticide results and look for links.
    

Detailed description: 
      There is increasing evidence that early life exposures may influence future health outcomes
      although there is a critical need to more fully understand how these may differ from
      exposures received later in life. The farm environment includes pesticides that have been
      suggested to increase cancer risk in both children and adults. A review of the literature
      identified crucial gaps in our knowledge and highlighted the need for accurate exposure
      assessment, including separate parental interviews, specific pesticide exposure questions,
      and semiquantitative exposure measures that can be used to confirm information obtained
      through questionnaires 2. Some studies suggest that the timing of exposure may be
      particularly important. For example, in a study of the insecticide DDT and breast cancer,
      researchers observed the highest risks among women exposed prior to age 14 compared to later
      in life 3. The agricultural environment also includes other exposures such as animals,
      allergens, and endotoxins. These exposures may influence immune function, particularly when
      exposed at a young age, and subsequently affect later cancer risk.

      The Agricultural Health Study (AHS) is a prospective cohort study of farmers and their
      spouses residing in North Carolina and Iowa, and commercial pesticide applicators residing in
      Iowa. At enrollment (1993-7) women (farmers and spouses of farmers) provided information on
      their children born since 1975, including name, gender, SSN and dates of birth. In previous
      analyses conducted using Iowa AHS data only for cancer incidence and all-cause mortality in
      children under the age of 19, findings suggested increased risks of incident cancer among
      these children associated with the use of certain pesticides by their parents. The mortality
      analysis focused on fatal injuries sustained, indicative of the dangerous nature of working
      on the farm6. In collaboration with researchers at the University of Iowa, we are currently
      updating the previous analysis with new cancer incidence information through 2011 and
      information provided by the University of Iowa, which has performed a linkage to Iowa birth
      certificates to identify additional children born to AHS participants from 1975-2009.

      With this proposal, we are proposing to further expand the linkages in Iowa to include
      children not previously included, and to link to the North Carolina registries for the first
      time to identify additional 2 births, cancer incidence and mortality. This will establish a
      unique cohort of agriculturally exposed offspring, with comprehensive information on their
      parents farming practices, as well as other information. These data will be used to evaluate
      the hypothesis that early life agricultural exposures influence cancer risk. Previous
      analyses have only focused on childhood cancers; we will include cancers diagnosed from birth
      through adulthood.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Offspring of Agricultural Health Study (AHS) cohort members (farmers and their spouses
        residing in North Carolina and Iowa, and commercial pesticide applicators residing in
        Iowa).
      
Keywords: Pesticide; Agriculture; Cancer; Childhood; Leukemia