Postmenopausal estrogen use affects risk for Parkinson disease.

Background: Although estrogen therapy has been associated with improved cognitive functioning, a reduced risk of dementia in women with Parkinson disease (PD), and a decreased risk of Alzheimer disease, estrogen therapy has not affected the risk of PD per se.

Objective: To determine whether postmenopausal women with PD differed from control subjects with regard to estrogen exposure.Design, Setting, and Patients A case-control design was used, abstracting questionnaire data obtained via interview from 133 female PD cases and 128 female controls during routine outpatient clinic visits in 1999 at a mid-Atlantic tertiary care referral center. There were 140 subjects (68 PD cases and 72 controls) who met the inclusion criteria. Main Outcome Measure Use of postmenopausal estrogen therapy.

Results: More women in the control group than in the PD group took postmenopausal estrogen (36 [50%] of 72 women vs 17 [25%] of 68 women; P<.003), and women who had taken postmenopausal estrogen were less likely to develop PD than those who had not (odds ratio, 0.40 [95% confidence interval, 0.19-0.84]; P<.02). Among PD cases only, postmenopausal estrogen use was not associated with age of onset.

Conclusion: Postmenopausal estrogen therapy may be associated with a reduced risk of PD in women.