Job Exposure Matrix (JEM)-Derived Estimates of Lifetime Occupational Pesticide Exposure and the Risk of Parkinson's Disease

Zeyan Liew,Anthony Wang,Jeff Bronstein,Beate Ritz

doi:10.1080/19338244.2013.778808

Abstract

ABSTRACT Studies that report an association between Parkinson's disease (PD) and occupational pesticide exposure often use self-reported exposure and none adjust for concomitant ambient pesticide exposure. For a population-based case-control study of PD conducted in California's heavily agricultural region, the authors developed a comprehensive job exposure matrix (JEM) to assess occupational exposure to pesticides. Relying on 357 incident cases and 750 population controls enrolled between 2001 and 2011, the authors estimated more than a 2-fold risk increase for PD among men classified as highly occupationally exposed. The authors also observed an exposure-response pattern and farming tasks with direct and intense pesticide exposures such as spraying and handling of pesticides resulted in greater risks than indirect bystander exposures. Results did not change after adjustment for ambient pesticide exposure. The authors provide further evidence that occupational pesticide exposure increases the risk of PD.

Highlights

Parkinson’s disease (PD) is the second most common neurodegenerative disorder leading to motor, cognitive and mood dysfunction with a major impact on quality of life
We conducted a population-based case-control study of PD in a largely agricultural region of Central California confirming previous reports that occupational exposures to pesticides in farming related jobs increase the risk of developing PD
We found an exposure response trend for PD with intensity of life-time cumulative pesticide exposures based on Job Exposure Matrix (JEM) derived measures

Summary

Introduction

Parkinson’s disease (PD) is the second most common neurodegenerative disorder leading to motor, cognitive and mood dysfunction with a major impact on quality of life. The vast majority of previous epidemiological studies relied on retrospective selfreporting of exposures raising questions about validity due to the possibility of differential recall bias since cases may be more inclined than control subjects to report exposures to suspected toxins as suggested previously.[14] This German study[14] found PD risk to be increased with self-reported pesticide use but not when a job exposure matrix was employed to assess pesticide exposures. Few studies utilized methods less influenced by subject recall such as exposure matrices or expert evaluations based on job history to assess occupational pesticide exposures but most of these studies were either very small[4,15] (

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