Authors' objectives: To determine whether there is any evidence on the (causal) association between exposure to certain chemicals, including trichloroethylene, organochlorides, diesel fumes, aluminum, titanium dioxide, nickel, zinc, n-Hexane and lead and the development of idiopathic Parkinson's disease.

Authors' results and conclusions: Trichloroethylene (TCE): there were some evidence, coming from a small case series, level of evidence 4 and a small twin/sibling case-control study, level of evidence 3 showing the potential association of exposure to TCE and development of PD. Other organochlorides: no published study provided such evidence was identified. Diesel fumes: the identified study failed to provide the relevant evidence. Aluminum: a small case-control level of evidence 3 and a large, administrative database based, retrospective cohort study level of evidence 3, provided, at best, conflicting evidence. Titanium dioxide: the identified study failed to provide the relevant evidence. Nickel: the identified study failed to provide the relevant evidence. Zinc: a small case-control level of evidence 3 provided negative evidence on the association. n-hexane: a small twin/sibling case-control study level of evidence 3provided a negative association. Lead: two small case-control level of evidence 3provided, at best, conflicting evidence. Regardless of the findings of these studies, the results have to be interpreted with caution since bias, chance and confounding effects cannot be eliminated in potentially affecting the observe outcomes. Furthermore, these studies need to be duplicated by other studies in order to provide a potential causal association assessment.

Authors' methods: We began our systematic review by conducting a comprehensive and systematic literature search on July 25, 2024. The search was done on commercial and non-commercial medical and occupational health databases. No limitation, such as on the language or date of publication was implemented in any of these searches. A manual search, on the references of the articles that were retrieved in full, was also conducted. Relevant primary studies identified from retrieved articles in the form of expert or systematic review articles were retrieved and the original (expert/systematic) review article would not be discussed further.

Project Status: Completed

URL for project: https://www.worksafebc.com/en/about-us/research-services/evidence-based-medicine-and-systematic-reviews

Year Published: 2024

URL for published report: https://www.worksafebc.com/en/resources/health-care-providers/guides/causal-association-between-exposure-certain-chemicals-development-idiopathic-parkinsons?lang=en

English language abstract: An English language summary is available

Publication Type: Mini HTA

Country: Canada

Organisation Name: WorkSafeBC

Contact Address: 6591 Westminster Highway, Richmond, BC, V7C 1C6 Canada. Tel: 604-231-8417; Fax: 604-279-7698

Contact Name: ebpg@worksafebc.com

Contact Email: ebpg@worksafebc.com

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