Objective: To explore sex differences in symptoms of prodromal Parkinson’s disease (PD) in large, population-based multi-centre cohorts of healthy individuals, PREDICT-PD and Healthy Brain Ageing (HeBA).

Background: Biological sex is an important factor in the development, clinical presentation, and progression of PD. However it is not well studied whether sex differences also occur in the prodromal phase of PD. The prodromal phase includes symptoms such as hyposmia, REM sleep behaviour disorder (RBD), depression, and anxiety which can occur decades before a diagnosis.

Method: We investigated sex differences in prodromal symptoms in the PREDICT-PD and HeBA cohorts. PREDICT-PD is an online UK cohort study that stratifies participants for risk of future PD. HeBA is a multi-centre population-based online study with centres in Innsbruck, Barcelona, Kassel and Luxembourg. We evaluated sex differences in prodromal symptoms including hyposmia, RBD, depression, and anxiety, using Wilcoxon sum rank tests, Fisher’s exact tests and chi-squared tests, without adjusting for covariates in this initial analysis.

Results: Data was available for 11,527 participants in PREDICT-PD and 27,415 participants in HeBA. Women represented the majority of participants in both cohorts (PREDICT-PD: 60.1%; HEBA: 59.1%). Due to the large number of individuals, many statistical comparisons were statistically significant. RBD appeared to be more common in men than in women. In PREDICT-PD where an enriched cohort was recruited for polysomnography (PSG), 1.7% in men had confirmed PSG-RBD vs. 0.4% in women. Possible RBD identified through questionnaire or self-report was also more common in men than in women: 25% vs. 17% in PREDICT-PD, and 16% vs. 13% in HeBA (p-values < 0.001). In PREDICT-PD, hyposmia identified through smell test or self-report was more common in men than in women (8.3% vs. 4.7%). However in HeBA, self-reported hyposmia was similar between men and women (both 8%). Anxiety and depression were more common in women than in men in both cohorts (p-values < 0.001).

Conclusion: We found differences between men and women in prodromal symptoms, including RBD, depression and anxiety, however statistically significant differences are likely due to the large sample sizes. We will expand this work using regression models with adjustment for relevant covariates, and meta-analyse results across cohorts to compare differences between them.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/sex-differences-in-prodromal-features-of-parkinsons-disease-evidence-from-large-multi-centre-cohorts/