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Parkinson's Diseases Susceptibility Genes and Pesticides

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified April 2015 by National Institute of Environmental Health Sciences (NIEHS).
Recruitment status was:  Recruiting
Information provided by:
National Institute of Environmental Health Sciences (NIEHS) Identifier:
First received: September 3, 2002
Last updated: October 5, 2015
Last verified: April 2015
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.

Parkinson's Disease

Study Type: Observational
Official Title: Parkinson's Diseases Susceptibility Genes and Pesticides

Resource links provided by NLM:

Further study details as provided by National Institute of Environmental Health Sciences (NIEHS):

Estimated Enrollment: 1200
Study Start Date: September 2000
Estimated Study Completion Date: November 2015
Estimated Primary Completion Date: November 2015 (Final data collection date for primary outcome measure)
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.

Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Newly diagnosed patients with idiopathic PD (first PD diagnosis after January 1998 who are currently living in one of the three target counties (Kern, Tulare, Fresno) and have lived in California for at least 5 years are eligible for participation. 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 same inclusion criteria will be applied as to the cases. 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
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Please refer to this study by its identifier: NCT00044590

United States, California
Beate Ritz, UCLA Department of Epidemiology Recruiting
Los Angeles, California, United States, 90095-1772
Contact: Beate R Ritz, MD, Ph.D.    310-206-7458   
Principal Investigator: Beate R Ritz, M.D., Ph.D.         
Sponsors and Collaborators
National Institute of Environmental Health Sciences (NIEHS)
  More Information Identifier: NCT00044590     History of Changes
Other Study ID Numbers: 10544-CP-001
Study First Received: September 3, 2002
Last Updated: October 5, 2015

Keywords provided by National Institute of Environmental Health Sciences (NIEHS):
Parkinson's disease
Genetic susceptibility

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 processed this record on April 28, 2017