Women with longer fertile life-spans have a lower risk of contracting Parkinson's disease, according to medical research in the United States.
"These findings suggest that longer duration of exposure to the body's own (endogenous) hormones may help protect the brain cells that are affected by Parkinson's disease," said the authors of the study.
A woman's fertile lifespan stretches from her first menstruation to menopause. Women with fertile life spans longer than 39 years had 25% lower risk of developing Parkinson's, compared to women with ones 33 years or shorter, said the researchers.
They also found that women who had four or more pregnancies were 20% more at risk for Parkinson's than those with three or fewer pregnancies. And women who underwent hysterectomy, or surgical menopause, had almost twice the risk of developing Parkinson's.
Still 'unanswered questions'
The risk was double if they had previously taken hormone therapy and stopped than if they had never taken hormone therapy. Taking hormones did not have any effect on Parkinson's risk for women who had natural menopause, the researchers said.
"This study does not support a role for treatment with hormone therapy in Parkinson's, but there are still many unanswered questions," said study author Rachel Saunders-Pullman, of Albert Einstein College of Medicine in Bronx, New York.
The study, funded in part by the US National Institutes of Health, involved 74 000 women with natural menopause and 7 800 with surgical menopause. Because Parkinson's disease is more common in men than in women, researchers have long hypothesised about the role of hormones in the disease. – (Sapa, February 2009)
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