St. Paul, Minn. – Women who consume little or no caffeine, but who take hormone replacement therapy, may reduce their risk of developing Parkinson’s disease, according to a study published in the March 11 issue of Neurology, the scientific journal of the American Academy of Neurology. However, HRT may increase disease risk in women who drink the equivalent of more than five cups of coffee per day.
Two large studies have previously shown that increased caffeine intake is associated with a lower risk of Parkinson’s disease in men. Studies in women, which to date have not factored in use of hormone replacement therapy, have been contradictory and inconclusive. Parkinson’s disease is less common in women, and some evidence suggests that estrogen may help protect the neurons that degenerate in this disease. Estrogen is the principal hormone in HRT, a common therapy in post-menopausal women.
Eighteen years of data from more than 77,000 were drawn from the Nurses’ Health Study. Information on hormone use and caffeine intake was collected from survey data.
Parkinson’s disease was diagnosed in 154 of the women during the study. Similar to some previous studies, there was no difference in the incidence of disease between women who did or did not use HRT, when that was the only variable considered. However, when caffeine consumption was also factored in, some unexpected results emerged.
In women who drank less than half a cup of coffee per day, HRT use was associated with a 65 percent reduction in relative risk of developing Parkinson’s disease, compared to those who did not use HRT. These results are in keeping with the hypothesis that estrogen may help protect women against the brain cell death that causes Parkinson’s disease.
The American Academy of Neurology, an association of more than 19,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.
For more information about the American Academy of Neurology, visit www.aan.com.
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