New Alzheimer's update for women using birth control pills or HRT

New Alzheimer's update for women using birth control pills or HRT A new study has offered important insights for women who have used birth control pills or hormone replacement therapy (HRT) A new study on Alzheimer's has been published with important insights for women with a history of being on HRT or taking birth control pills. Researchers say women are more affected by Alzheimer's than men. This is potentially in part due to fluctuations in estrogen levels in life - hormones that play a key role in female reproductive health. Now academics say the new research offers 'striking' information - particularly for women who used oral contraception during their reproductive years and later received HRT, a treatment used for symptoms of menopause. The study found that a lengthier reproductive lifespan and a history of taking contraceptive pills or menopausal hormone therapy were linked to certain indicators of blood vessel health in the brain. That is according to research published on Wednesday, November 4 in Neurology, the medical journal of the American Academy of Neurology. "Women are affected by Alzheimer's disease more often than men. This may be related, in part, to fluctuations in estrogen levels throughout life," said Anna Marseglia, PhD, of Karolinska Institutet in Stockholm, Sweden. "Estrogen is known to have protective effects on both neuronal cells and blood vessels in the brain. However, its potential role in women's cerebrovascular health in later life has been largely understudied. Our study found that factors associated with longer estrogen exposure were associated with fewer signs of cerebral small vessel disease and better brain health in older age." The study involved 352 women aged 70 who showed no signs of cognitive impairment at the outset of the research. Scientists examined reproductive factors connected to lifetime oestrogen exposure, calculating each woman's reproductive lifespan, defined as the number of years between her first menstrual period and menopause or surgical removal of the ovaries. On average, women had a reproductive lifespan of 37 years. They also recorded whether participants had ever used contraceptive pills or menopausal hormone therapy. Of those taking part, 73% had used contraceptive pills and 61% had used or were currently using menopausal hormone therapy. Participants went through magnetic resonance imaging (MRI) brain scans at ages 70 and 75. Researchers examined the scans for four indicators of cerebral small vessel disease. This affects tiny blood vessels in the brain and is associated with stroke, cognitive impairment and dementia. The indicators were: - areas of damaged tissue known as white matter hyperintensities; - microbleeds; - small fluid-filled cavities called lacunes; - and moderate to severe enlargement of spaces surrounding blood vessels. Each participant received a score from zero to four, with one point awarded for each sign identified. After accounting for factors such as education, number of pregnancies and total months breastfeeding, researchers discovered that women with a longer reproductive lifespan had 8% lower odds of presenting with two or more signs of cerebral small vessel disease. In a separate analysis that accounted for factors including education, high blood pressure and heart disease, women who had used or were still using menopausal hormone therapy faced 59% less risk of having a greater small vessel disease "burden". This included fewer microbleeds and enlarged spaces around blood vessels. Contraceptive pills and menopausal hormone therapy use were linked to greater "integrity" of the brain's white matter microstructure. This is an early marker of healthier brain tissue. Researchers also found that women who had taken oral contraceptives and subsequently received menopausal hormone therapy showed the most favourable vascular brain health. This group showed the lowest amount of cerebral small vessel disease and the healthiest white matter "integrity" compared with women who had never used hormonal therapies. "What was particularly striking was that the most favorable vascular brain health was observed among women who had used oral contraceptives during their reproductive years and later received menopausal hormone therapy" said Marseglia. "This suggests that hormonal factors acting across different stages of a woman's life may have cumulative associations with cerebrovascular health in older age. While these findings do not establish cause and effect, they underscore the importance of considering women's reproductive and hormonal history when studying brain aging and dementia risk not only in relation to Alzheimer's disease but also to vascular disease." Dr Honorine Lebraud, Senior Partnerships Manager at Alzheimer's Research UK, said: "This study builds on growing evidence that reproductive and hormonal history may play a role in brain health as women age. "Researchers found that women who had a longer reproductive lifespan and therefore experienced a longer period of natural oestrogen exposure, from their first period to menopause, tended to show fewer signs of damage to the brain's small blood vessels. "Meanwhile, women who had used oestrogen-based oral contraceptives or menopausal hormone therapy were more likely to exhibit additional signs of improved brain health.. "While these findings are interesting, further research is needed to understand these patterns, especially as nearly two-thirds of people with dementia are women. As an observational study, it cannot show that hormone exposure directly improves brain health or reduces dementia risk. "For now, our advice remains unchanged. Women should not start or stop taking the contraceptive pill or HRT to reduce their dementia risk based on these findings. Decisions about hormonal treatments should continue to be made with a healthcare professional, based on individual health needs." Researchers make clear that limitations of the research include the fact that hormone exposure was self-reported by participants during data collection interviews, meaning recollections may not always have been entirely accurate. Researchers were also unable to monitor individual hormone levels over time, and there was insufficient detailed information on participants' oral contraceptive and hormone therapy usage.