New evidence suggests that the early loss of naturally produced oestrogen - a side-effect of a hysterectomy - may increase the risk of Parkinson's disease.
In this study, researchers from the Mayo Clinic in Rochester, Minnesota, examined the medical records of 72 women who developed Parkinson's disease between 1976 and 1995 in Olmsted County, Minnesota. These were compared with age-matched controls drawn from the general population.
Women with Parkinson's disease were more than three times more likely to have undergone a hysterectomy than the controls, and more than twice as likely to have had an early menopause.
Postmenopausal oestrogen use for six months prior to the study was also less common among the women who developed Parkinson's disease compared with controls (8 vs 14 per cent), leading the researchers to speculate that naturally produced oestrogen may have an as yet unexplored role in preventing Parkinson's disease (Mov Disord, 2001; 16: 830-7).
* As if to underscore this association, a new US study involving postmenopausal women has shown that oestrogen replacement therapy does not retard a decline in cognitive function.
Researchers from Johns Hopkins University Bloomberg School of Public Health in Baltimore, Maryland, collected data from 2859 women, aged 48-67 years, who had participated in the ARIC (Atherosclerosis Risk in Communities) study.
The women had their cognitive functioning tested twice between 1990 and 1998 and, after adjustment for confounding factors, there appeared to be no difference between those who used HRT and those who did not. This finding held true for current oestrogen use and duration of oestrogen use, and for women of all ages (Am J Epidemiol, 2001; 154: 733-9).