Study suggests why some women have a lower risk of stroke

The study took place in China and involved 122,939 post-menopausal women with an average age of 58 at the start of the study. Participants answered a range of lifestyle questions, such as smoking, alcohol use, and how much they exercised.  

They also answered questions about their reproductive health, including date of their first period, number of pregnancies, start of menopause, and contraceptive use.  

After nine years of follow-up, researchers found that the women who had the longest exposure to oestrogen in their lives (because they had a longer reproductive cycle) were at a lower risk of stroke. When findings were adjusted to account for other stroke risk factors, such as smoking, high blood pressure, and exercise, the longest group’s risk of stroke was five percent less overall. 

Women with a higher total exposure to oestrogen also had a lower risk of stroke. Researchers estimated oestrogen exposure based on each woman’s reproductive lifespan, as well as number of pregnancies and use of hormonal contraceptives – both associated with higher levels of oestrogen – and breastfeeding, which reduces oestrogen.  

One of the authors of the study, Dr Peige Song, of the Zhejiang University School of Medicine in Hangzhou, China, said: “These findings might help with new ideas for stroke prevention, such as considering screenings for people who have a short lifetime exposure to oestrogen.” 

An ischaemic stroke is the most common form of stroke, and is caused by a blockage in the blood supply to the brain, while a haemorrhagic stroke is caused by a bleed in or around the brain, and can be either an intracerebral stroke (a bleed into the brain) or a subarachnoid stroke (a bleed on the surface of the brain).  

When looking at the different types of stroke, people in the group with the longest oestrogen exposure had a five percent lower risk of ischemic stroke and a 13% lower risk of intracerebral stroke.  There was no reduction in the risk of subarachnoid stroke.

“Oestrogen exposure throughout life could potentially be a useful indicator of a person’s risk of different types of stroke following menopause,” said Song.  

“However, more research is needed on the biological, behavioural, and social factors that may contribute to the link between oestrogen exposure and stroke risk across a woman’s lifespan.” 

Oestrogen is a hormone that affects far more in our bodies than just our reproductive system – in fact, it has an effect on every organ in the body.  It does a lot to help the health of our circulatory system by helping to to control blood pressure and cholesterol levels and reduce the build-up of fatty plaque in the artery walls. 

Speaking to Exceptional, Dr Rebecca Lewis, menopause specialist and director of the Balance app, described the risk that low levels of oestrogen can bring.  

“We know how beneficial oestrogen is for our bodies in many ways and when younger women have low oestrogen levels, they are at risk of many diseases including heart attacks, type 2 diabetes, dementia and osteoporosis.”

Because of this, women who go through early menopause (below the age of 40) or who have premature ovarian insufficency are encouraged to consider treatment to reduce their risk.

But the role of oestrogen in the body is a complicated one. It is also linked to an increase in the risk of blood clots and of breast cancer. Some research has found that women with a longer reproductive age have an increased breast cancer risk.

You can reduce your risk of stroke and heart disease (as well as many cancers) by maintaining a healthy diet and exercise regime, not smoking, and limiting alcohol intake. These lifestyle factors are recommended by The Stroke Association and The British Heart Foundation as helping to lower your risk of stroke.  

Via: ScienceDaily