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Some challenges in the epidemiological study of Parkinson's disease
| No diagnostic test |
| • Examination by expert most reliable |
| • No criterion always predicts pathology |
| Long preclinical period |
| • Exposure may be years before signs |
| Late‐life disorder |
| • Risk factor identification retrospective |
| • Diagnostic accuracy in relatives poor |
| Relatively rare |
| • Large base population needed |
| No registries; not reported |
| • ‘True’ distribution of disease not certain |
