Occupational Characteristics and Patterns as Risk Factors for Parkinson's Disease: A Case Control Study.

Background: Associations have been reported between the risk of Parkinson's disease (PD) and employment in certain fields. Most studies have focused on toxic exposures as potential causal explanations. However, PD also has been associated with personality characteristics that may influence occupational choices and patterns.
Objective: This study evaluates the role of personality as indicated by occupational choices and employment patterns in the risk for PD.
Methods: In-person interviews were conducted to assess occupational histories and early-adult personality indicators among 89 PD patients and 99 controls.
Results: PD cases had fewer lifetime jobs than controls (mean for cases = 4.38 ± 2.20; mean for controls = 5.00 ± 2.26; p = 0.03). Among women, PD was positively associated with more complex work with people (OR = 1.45, 95% CI 1.12-1.89), representing a 95% increased risk for PD comparing women with the greatest complexity of work with those requiring the least complexity of work with people. Women PD cases also performed less complex work with things compared with controls (OR = 0.69 (95% CI 0.53-0.90)), translating into a 13-fold increased risk for PD among women whose work involved the least complex work with things compared with the most. The numbers of jobs and job types were associated with taking more activity risks as a young-adult (r = 0.19, p = 0.02; r = 0.26, p = 0.001, respectively).
Conclusions: Cases with PD held fewer lifetime jobs compared with controls. Occupational complexity was associated with the risk for PD among women, but not men. Further consideration of the possible influence of personality on occupational choices is warranted.