Open Access Case control study

Occupational risk factors for Parkinson's disease: a case-control study in Japan

Keiko Tanaka1*, Yoshihiro Miyake1, Wakaba Fukushima2, Satoshi Sasaki3, Chikako Kiyohara4, Yoshio Tsuboi5, Tatsuo Yamada5, Tomoko Oeda6, Takami Miki7, Nobutoshi Kawamura8, Nobutaka Sakae8, Hidenao Fukuyama9, Yoshio Hirota2, Masaki Nagai10 and the Fukuoka Kinki Parkinson's Disease Study Group11

Author Affiliations

1 Department of Preventive Medicine and Public Health, Faculty of Medicine, Fukuoka University, Fukuoka, Japan

2 Department of Public Health, Osaka City University Graduate School of Medicine, Osaka, Japan

3 Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan

4 Department of Preventive Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

5 Department of Neurology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan

6 Department of Neurology, Utano National Hospital, Kyoto, Japan

7 Department of Geriatric Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan

8 Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

9 Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan

10 Department of Public Health, Saitama Medical University Faculty of Medicine, Saitama, Japan

11 Other members of the Study Group are listed in the Appendix

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BMC Neurology 2011, 11:83  doi:10.1186/1471-2377-11-83

Published: 7 July 2011

Abstract

Background

The evidence for associations between occupational factors and the risk of Parkinson's disease (PD) is inconsistent. We assessed the risk of PD associated with various occupational factors in Japan.

Methods

We examined 249 cases within 6 years of onset of PD. Control subjects were 369 inpatients and outpatients without neurodegenerative disease. Information on occupational factors was obtained from a self-administered questionnaire. Relative risks of PD were estimated using odds ratios (ORs) and 95% confidence intervals (CIs) based on logistic regression. Adjustments were made for gender, age, region of residence, educational level, and pack-years of smoking.

Results

Working in a professional or technical occupation tended to be inversely related to the risk of PD: adjusted OR was 0.59 (95% CI: 0.32-1.06, P = 0.08). According to a stratified analysis by gender, the decreased risk of PD for persons in professional or technical occupations was statistically significant only for men. Adjusted ORs for a professional or technical occupation among men and women were 0.22 (95% CI: 0.06-0.67) and 0.99 (0.47-2.07), respectively, and significant interaction was observed (P = 0.048 for homogeneity of OR). In contrast, risk estimates for protective service occupations and transport or communications were increased, although the results were not statistically significant: adjusted ORs were 2.73 (95% CI: 0.56-14.86) and 1.74 (95% CI: 0.65-4.74), respectively. No statistical significance was seen in data concerning exposure to occupational agents and the risk of PD, although roughly a 2-fold increase in OR was observed for workers exposed to stone or sand.

Conclusion

The results of our study suggest that occupational factors do not play a substantial etiologic role in this population. However, among men, professional or technical occupations may decrease the risk of PD.