We do know a few things about hormone replacement therapy and Parkinson's disease, though. Estrogen replacement is protective against the incidence of dementia which occurs in nearly 30% of Parkinson's Disease patients. Since Parkinson's is more common in men, it raises the suspicion that estrogen has a protective role. It appears that estrogen's antioxidant properties have a direct effect on the survival and recovery of dopamine neurons in early Parkinson's disease. Also the risk of Parkinson's Disease increases after therapy with tamoxifen which is an anti-estrogen drug given to some women after breast cancer. Testosterone replacement also improves the non-motor symptoms of Parkinson's Disease.
Anne R Trussell MD