Hysterectomy, menopause, and estrogen use preceding Parkinson's disease: An exploratory case-control study

We studied the association of Parkinson's disease (PD) with type of menopau se (natural or surgical). age at menopause. and postmenopausal estrogen rep lacement therapy using a case-control design. We used the medical records-l inkage system of the Rochester Epidemiology Project to identify 72 women wh o developed PD in Olmsted County, MN, during the twenty years 1976-1995. Ea ch incident case was matched by age (+/- 1 year) to a general population co ntrol subject. We collected exposure data through review of the complete me dical records of cases and control subjects in the system. PD cases had und ergone hysterectomy (with or without unilateral oophorectomy) significantly more often than control subjects (odds ratio [OR] = 3.36; 95% confidence i nterval [CI] = 1.05-10.77). In addition, PD cases had experienced early men opause (less than or equal to 46 years) more commonly than control subjects (OR = 2.18, 95% CI = 0.88-5.39). Finally, PD cases had used estrogens oral ly or parenterally for at least 6 months after menopause less frequently (8 %) than control subjects (14%; OR = 0.47, 95% CI = 0.12-1.85). However, the findings for early menopause and estrogen replacement therapy were not sta tistically significant. Despite the limited sample size of this exploratory study, we hypothesize that there is an increased risk of PD in conditions causing an early reduction in endogenous estrogen. This hypothesis needs to be confirmed in a larger study. (C) 2001 Movement Disorder Society.