Parkinson’s disease (PD) is preceded by a premotor phase of unknown duration. Dopaminergic degeneration during this phase may lead to subtle cognitive and behavioural changes, such as decreased novelty seeking. Consequently, premotor subjects might be most comfortable in jobs that do not require optimal dopamine levels, leading to an overrepresentation in structured and predictable occupations, or an underrepresentation in artistic occupations. In a case–control study, 750 men with PD (onset ≥40 years) and 1300 healthy men completed a validated questionnaire about their lifetime occupational status. Occupations were classified using the RIASEC model. Odds ratios (ORs) were calculated for the conventional and artistic categories, both for the most recent occupation before symptom onset, and for the very first occupation. Because farming has been associated with a PD risk, ORs were calculated separately for farming. A reduced risk of PD was found for men with an artistic occupation late in life (OR 0.14, 95 % CI 0.04–0.53), while an artistic first occupation did not prevent PD (OR 0.72, CI 0.32–1.59). Conventional occupations showed no increased risk (recent: OR 1.07, CI 0.70–1.64; first: OR 1.14, CI 0.77–1.71). In support of previous reports, farming was associated with an increased risk of PD (recent: OR 2.6, CI 1.4–4.6; first: OR 2.7, CI 1.6–4.5). PD patients were older than controls, but various statistical corrections for age all lead to similar results. Artistic occupations late in life are associated with a reduced risk of subsequent PD, perhaps because this reflects a better preserved dopaminergic state. No initial occupation predicted PD, suggesting that the premotor phase starts later in life.

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Journal of Neurology: official journal of the European Neurological Society
Department of Psychology