The incidence of PD was lower among those with higher levels of physical activity.

Is physical activity associated with a lower incidence of Parkinson’s disease (PD) in women? To find out, investigators analysed long-term data from the ongoing E3N cohort study of nearly 100,000 women affiliated with a French national health plan (Eur J Epidemiol 2022;  37: 513-523).

The researchers used lagged analyses to compare physical activity trajectories between 1196 PD cases and 23,879 matched controls and applied a time-varying latent physical activity (LPA) variable with latent-process mixed models. PD diagnosis was based on medical records or a validated drug claim algorithm, and a nested case-control study was applied to LPA trajectories using multivariable linear mixed models and a retrospective timescale. A Cox proportional hazards model using age as the timescale was adjusted for confounders and was used to determine the association between time-varying LPA and incidence of PD.

Results were as follows:

• LPA was significantly lower in PD cases than in controls during a 29-year follow up; the difference began to widen 10 years before PD diagnosis (p-interaction=0.003)
• PD incidence decreased with increasing physical activity (p-trend=0.001)
• PD incidence was 25% lower among those in the highest versus lowest physical activity quartiles.

Comment: These data strongly suggest that a higher physical activity level is associated with lower PD incidence in women. The study design and 29 years of follow up support the idea that the association is not explained by reverse causation. These findings are important because of the potentially long prodromal phase of PD, which has been a challenge for investigators to account for, and because this association between physical activity and PD had previously been shown only in men. Men and women potentially at risk for one day being diagnosed with PD may consider lifelong exercise.

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

Michael S. Okun, MD, Adelaide Lackner Professor and Chair of Neurology and Executive Director, Fixel Institute for Neurological Diseases, University of Florida McKnight Brain Institute, Gainesville, USA.

Portugal B, et al. Association of physical activity and Parkinson disease in women: long-term follow-up of the E3N cohort study. Neurology 2023 May 17; e-pub (https://doi.org/10.1212/WNL.0000000000207424).

This summary is taken from the following Journal Watch title: Neurology.