Hormone replacement therapy (HRT) is not associated with cognitive decline when women have recently started the menopause or do not have diabetes, according to US researchers.
They said they had sought to further investigate the impact of HRT on cognition, in the wake of contrasting findings from previous studies.
“These data are sorely needed to guide women’s healthcare during and after the menopausal transition”
They highlighted that the influential Women’s Health Initiative-Memory Study (WHIMS) and WHI-Study of Cognitive Aging (WHISCA) had suggested worsening cognition linked with hormone therapy.
But these studies differed from previous research findings that had suggested a protective effect on cognition associated with hormone therapy.
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As a result, the researchers from University of Wisconsin and George Washington University looked at two separate studies published since WHIMS and WHISCA.
These were the Kronos Early Estrogen Prevention Study-Cognitive and Affective Study (KEEPS); and the Early Versus Late Intervention Trial with Estradiol-Cognitive Endpoints (ELITE).
The four-year KEEPS study looked at the early initiation of HRT in around 700 women who were at the beginning of their menopause to see if it could delay the onset of clinical cardiovascular disease.
Specifically, it looked at the effects of oestrogen and progesterone on the development of atherosclerosis in women when HRT was initiated within three years of the menopausal transition.
“Healthy women who started taking HRT in their early fifties, shortly after menopause, can feel reassured”
Meanwhile, ELITE examined the effects of oral oestrogen on the progression of early subclinical atherosclerosis and cognitive decline in healthy postmenopausal women.
It involved around 600 patients who were treated with HRT for an average of five years.
The results of the new analysis of the two trials showed no negative effect on cognition in women who had initiated hormone therapy between the ages of 50 and 54.
In contrast, those who initiated hormone therapy between 65 and 79 demonstrated reductions in global cognition, working memory and executive functioning.
Women on hormone therapy with type 2 diabetes also showed a higher risk of cognitive impairment compared to non-diabetic women on hormone therapy.
Study author Dr Carey Gleason, from the University of Wisconsin School of Medicine and Public Health, said: “These findings add to our understanding of the complex effects of hormones on the brain.
“These data are sorely needed to guide women’s healthcare during and after the menopausal transition and to help women make personalised and informed decisions regarding management of their menopausal symptoms and the prevention of future adverse health outcomes,” she said.
The new research into the cognitive effects of hormone replacement therapy was presented last week at the Alzheimer’s Association International Conference (AAIC) in Chicago.
Dr Doug Brown, chief policy and research officer at Alzheimer’s Society, said: “Healthy women who started taking HRT in their early fifties, shortly after menopause, can feel reassured, as this research suggests there isn’t a link to brain decline with taking HRT from this time.
Dr Doug Brown
“Although the women studied who started HRT post fifties did show declines in memory and cognition, the research didn’t go far enough to see whether this decline led to dementia,” he said.
“And other factors, like lifestyle, could be at play,” he said. “For example, within this very study is evidence suggesting women taking HRT with type 2 diabetes could be at greater risk.”
Dr Brown said the new results added to “our understanding of how hormones can influence our risk of dementia”, but “many unanswered questions” remained about understanding risk reduction.
“If you’re considering or going through hormone therapy you shouldn’t be over worried about increasing your risk of getting dementia,” he added.