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Parkinson's Diseases Susceptibility Genes and Pesticides

This study has been completed.
Sponsor:
Collaborator:
University of California, Los Angeles
Information provided by (Responsible Party):
Beate Ritz, University of California, Los Angeles
ClinicalTrials.gov Identifier:
NCT00044590
First received: September 3, 2002
Last updated: May 12, 2017
Last verified: May 2017
  Purpose
Parkinson's disease (PD) occurrence is higher in rural than in urban populations of industrialized countries. Epidemiologic and human tissue studies suggest that pesticides may be responsible for causing dopaminergic cell death at increased rates. While many pathophysiologic pathways may be involved in the neurodegeneration responsible for PD, genetic factors are likely to determine a general susceptibility to neurodegeneration.

Condition
Parkinson's Disease

Study Type: Observational
Study Design: Observational Model: Case-Control
Time Perspective: Other
Official Title: Parkinson's Diseases Susceptibility Genes and Pesticides

Resource links provided by NLM:


Further study details as provided by Beate Ritz, University of California, Los Angeles:

Biospecimen Retention:   Samples With DNA
Blood, saliva, urine, and stool samples

Enrollment: 1870
Actual Study Start Date: September 1, 2000
Study Completion Date: November 30, 2016
Primary Completion Date: November 30, 2016 (Final data collection date for primary outcome measure)
Groups/Cohorts
Cases
Patients with Parkinson's Disease
Controls
Controls, subjects without Parkinson's Disease

Detailed Description:
While many pathophysiologic pathways may be involved in the neurodegeneration responsible for PD, genetic factors are likely to determine a general susceptibility to neurodegeneration. There are a number of genetic polymorphisms of genes such as those coding for the cytochrome p450 super-family of genes referred to as 'susceptibility genes'. However, they are generally not sufficient to cause disease unless a person encounters exposure to an environmental toxin: the disease is caused by a gene-environment interaction. Thus, it is imperative to assess genetic susceptibility in individuals exposed to a toxin. We will test the gene-environment interaction hypothesis by conducting an epidemiologic population-based case-control study of newly diagnosed PD patients from three rural California counties: Kern, Fresno, and Tulare. Over a four year period, we expect to collect 400 cases referred to us by local neurologists, farm worker clinics, and Parkinson's foundations. For each case, one population control will be selected at random from residential parcel maps and Medicare databases and, in addition, one unaffected sibling control and - when possible - affected siblings to avoid potential biases and inefficiencies inherent in the use of each type of control. For each study subject, an environmental and occupational pesticide exposure estimate will be derived using California pesticide-use reporting (PUR) data and information about pesticide application on crops in combination with crop patterns shown in satellite images and aerial photographs; in addition, extensive exposure interviews will be conducted with all study subjects. In a three-tiered approach to examine the effects of gene-environment interactions we will: 1) test for association (and linkage) of PD to selected loci associated with PD in earlier studies using multiallelic repeat markers and genotyping; 2) test for association using intragenic single nucleotide polymorphisms (SNPs) of 50 candidate genes arrayed to create "the PD array"; and 3) use future technical possibilities to screen for genome wide associations using array technology to scan 5,000-10,000 SNPs throughout the genome. Data analysis will employ hierarchical modeling procedures to take into account multiple comparison issues and to incorporate prior knowledge such as increased neurotoxicity due to the interaction of gene products and chemicals.
  Eligibility

Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Our case population consists of patients with newly diagnosed idiopathic Parkinson's disease living in central California; they will be patients who have elicited care from health care providers. Controls will be randomly selected from Medicare records and matched to cases according to age, race, and sex.
Criteria

Case population inclusion criteria:

  • first Parkinson's disease (PD) diagnosis after January 1998
  • currently living in one of the three target counties (Kern, Tulare, Fresno)
  • have lived in California for at least 5 years

Case population exclusion criteria:

  • have not been diagnosed with idiopathic PD
  • first PD diagnosis before January 1998
  • currently living outside of Kern, Tulare, or Fresno counties
  • have lived in California for fewer than 5 years

Control population inclusion criteria:

  • have never been diagnosed with PD
  • currently living in one of the three target counties (Kern, Tulare, Fresno)
  • have lived in California for at least 5 years

Control population exclusion criteria:

  • have been diagnosed with PD
  • currently living outside of Kern, Tulare, or Fresno counties
  • have lived in California for fewer than 5 years

For each patient, one or more unaffected sibling controls and one population control will be recruited. The population control are being selected randomly from Medicare records (95% of all controls) and residential parcel listings (for those patients younger than 65 years of age only). The controls are being marginally matched to cases according to 5-year age categories (e.g. 50-54, 55-59, 60-64, etc.), race (white, African-American, Asian, Hispanic, other), and sex. All study cases by definition will be patients who elicited care from health care providers. We are aiming to enroll every newly diagnosed PD patient into our study and expect patient population participating in our study that is as diverse as the rural population.

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00044590

Locations
United States, California
Beate Ritz, UCLA Department of Epidemiology
Los Angeles, California, United States, 90095-1772
Sponsors and Collaborators
National Institute of Environmental Health Sciences (NIEHS)
University of California, Los Angeles
Investigators
Principal Investigator: Beate Ritz, MD, PhD UCLA Department of Epidemiology
  More Information

Responsible Party: Beate Ritz, Principal Investigator, University of California, Los Angeles
ClinicalTrials.gov Identifier: NCT00044590     History of Changes
Other Study ID Numbers: 10544-CP-001
Study First Received: September 3, 2002
Last Updated: May 12, 2017
Individual Participant Data  
Plan to Share IPD: Undecided

Keywords provided by Beate Ritz, University of California, Los Angeles:
Parkinson's disease
Pesticides
Genetic susceptibility
Polymorphisms

Additional relevant MeSH terms:
Parkinson Disease
Disease Susceptibility
Parkinsonian Disorders
Basal Ganglia Diseases
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Movement Disorders
Neurodegenerative Diseases
Disease Attributes
Pathologic Processes

ClinicalTrials.gov processed this record on May 25, 2017