Risk of Cognitive Decline in Women with Parkinson's Disease Is Reduced by Early Age at Menarche

Parkinson's disease (PD) is a neurodegenerative disorder affecting men more frequently than women, a difference that might be due to many factors, including sexual hormones. Estrogens seem to confer a protective effect on the nigrostriatal pathway in experimental studies but their effects on cognition in patients with PD are unknown.

To investigate the impact of the exogenous and endogenous estrogens on cognitive impairment in women with PD.

We recruited and consecutively interviewed outpatient women affected by PD. Each patient underwent a cognitive assessment via the Montreal Cognitive Assessment scale (MoCA), an anamnestic collection of the reproductive lifespan variables and clinical features. We investigated if some of the reproductive lifespan variables investigated could predict cognition outcomes in post-menopausal women with PD.

A total of 90 women with PD were recruited. Women with MoCA ≥ 26 (n = 27) had a lower median age at menarche (11 [11,12] vs. 13 [12-14], p < 0.0001), lower disease duration in years (8.3 [6.1-12.7] vs. 9.4 [6-12.7], p = 0.6), and less advanced disease (1 [1,2] vs. 2 [1-3], p = 0.02). Among all the reproductive life-span variables, only earlier age at menarche significantly predicted higher scores on MoCA (aOR = 0.5 [0.3-0.8], p = 0.005). No other clinical and reproductive factors have been shown to have an influence on cognitive scores.

Age at menarche correlated with cognitive outcomes. Our study suggests that earlier exposure to endogenous estrogens during a phase of development and plasticity of the brain might preserve women with PD from cognitive decline.