Women who have had multiple children may have a lower risk of dementia owing to a higher exposure of oestrogen, research suggests
Women who have had multiple children may have a reduced risk of dementia, research suggests.
Experts have found that higher estrogen exposure throughout a woman’s life can lead to a healthier brain.
Those with a longer ‘reproductive lifespan’, or who have had multiple children, accumulate higher exposure to the hormone.
This appears to lead to a lower risk of cerebral small vessel disease – a condition resulting from damage to small blood vessels in the brain and linked to cognitive impairment and dementia.
Researchers analyzed 9,000 postmenopausal women with an average age of 64 in Britain.
Women who have had multiple children may be at reduced risk of dementia, research suggests (stock image)
Participants answered questions about reproductive health, including their age at their first period, when they started menopause and their number of pregnancies.
They also had brain scans to look for cerebral small vessel disease.
The scientists calculated lifetime exposure to hormones by adding the number of years women were pregnant to the length of their reproductive lifespan, the number of years between the first menstrual period and menopause.
The average lifetime exposure to hormones was 40 years. Analysis revealed that those with higher lifetime exposure to hormones had lower volume of white matter hyperintensity – an indicator of cerebral small vessel disease.
The team also found that taking oral contraceptives (HRT) did not appear to change the beneficial effects of pregnancies or reproductive longevity.
Study author Kevin Whittingstall, from the University of Sherbrooke in Quebec, Canada, said: ‘Our study highlights the crucial role of reproductive history in shaping the female brain throughout life.’
Writing in the journal Neurology, he added that the results “highlight the need to integrate reproductive history into the management of brain health in postmenopausal women.”
Previous studies have shown that the incidence of certain diseases – for example cerebral small vessel disease – increases after menopause, which is often related to the absence of hormones.
Experts have found that higher estrogen exposure throughout a woman’s life can lead to a healthier brain
Until now, it remained unknown whether the amount of hormone exposure before menopause extends the period of protection afterwards. A separate study published in 2021 found that women exposed to higher amounts of estrogen throughout their lives had larger amounts of gray matter in their brains.
Gray matter is an important part of the nervous system and is involved in sensory perception such as vision and hearing, memory, speech and decision-making.
The researchers at Weill Cornell Medicine in New York found that for every additional year a woman was exposed to estrogen in her life, the average volume of gray matter in certain parts of the brain increased by 1 percent.
For each additional child a woman had, the volume of gray matter increased by an average of 2 percent.