Objective: Objective: To evaluate whether reproductive factors and use of exogenous hormones are associated with the risk of Parkinson’s disease (PD) in women.

Background: Background: Despite experimental studies suggesting a neuroprotective role for oestrogens,[1,2] results from epidemiological studies on the relation between reproductive factors and PD in women are conflicting.[3,4]

Method: Methods: We used the data from 98,067 women (age at inclusion: 39-66) enrolled in 1990 in the E3N prospective cohort study and followed until 31/12/2018. Potential PD cases, identified through a multistep process based on self-administered questionnaires, antiparkinsonian drug claims, and death certificates, were validated by an expert panel. The association of baseline reproductive characteristics (age at menarche, parity, breast feeding, type and age at menopause) and use of exogenous hormones (oral contraceptives [OC], menopausal hormonal treatment [MHT]) with PD incidence was investigated using Cox models with age as the time scale and adjusted for rural living, smoking, and diabetes.

Results: Results: 1,246 incident PD cases were identified (mean follow-up=26.7y; incidence rate=47.6/100,000 person-years). Women with early (<12y; hazard ratio [HR]=1.22, 95% confidence interval [CI]=1.04-1.42) or late (>13y; HR=1.18 [1.03-1.35]) age at menarche were at greater PD risk than women with menarche at 12-13y (p-quadratic trend<0.01). Nulliparity was not associated with PD (HR=1.10 [0.86-1.39]), but PD risk was greater in women with ≥2 children than in women with 1 child (HR=1.23 [1.03-1.47]). Overall, menopause was not associated with PD (HR=0.98 [0.84-1.16]); however, among post-menopausal women, women with artificial menopause were at greater risk than women with natural menopause (HR=1.40 [1.14-1.73]). Age at menopause was not associated with PD after adjusting for type of menopause. Regarding exogenous hormone use, ex-MHT users at baseline (HR=1.32 [1.03-1.67]), but not current MHT users (HR=1.04 [0.86-1.25]), had increased PD risk to never users. By contrast, breast feeding and ever use of OC were not significantly associated with PD.

Conclusion: Conclusions: Our findings support a link between some characteristics of women’s reproductive history (early or late age at menarche, number of children, artificial menopause, MHT use) and the risk of developing PD later in life.

References: [1] Sawada H, Shimohama S. Estrogens and Parkinson disease: novel approach for neuroprotection. Endocrine. 2003;21:77-79. [2] Brann DW, et al. Neurotrophic and neuroprotective actions of estrogen: basic mechanisms and clinical implications. Steroids. 2007;72:381-405. [3] Lv M, et al. Reproductive factors and risk of Parkinson’s disease in women: A meta-analysis of observational studies. Behav Brain Res. 2017;335:103-110. [4] Canonico M, et al. Bilateral oophorectomy is associated with higher risk of Parkinson’s disease in post-menopausal women: a French population-based case-control study. Movement Disorders. 2021; in press.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/reproductive-factors-and-risk-of-parkinsons-disease-in-women-preliminary-results-from-the-french-prospective-cohort-e3n/