Higher lifetime estrogen levels tied to 13% lower risk

For the study, the researchers examined health data from 122,939 postmenopausal women with no prior stroke at baseline from the China Kadoorie Biobank study. The participants were between 40 and 79 years old and were followed for an average of 8.9 years.

They were asked to provide information about their reproductive history, including the age at which puberty began, the age at which menopause began, and the number of pregnancies they had. They also provided information about their use of birth control pills.

The women were then divided into four groups according to their reproductive lifespan (RL), or the number of years between the onset of puberty and menopause. Those in the shortest RL group had up to 31 reproductive years, while those in the longest RL group had 36 years or more.

The researchers also collected data on stroke rates. During the study, they recorded 15,139 new-onset stroke cases.

The researchers found that 13.2% of women in the longest RL group had a stroke, compared to 12.6% of women in the shortest RL group.

However, after adjusting for factors such as smoking, age, and physical activity, they found that participants in the longest RL group actually had a 5% lower risk of all types of stroke than participants in the shortest group.

Specifically, when examining different stroke subtypes, they found that those in the longest RL group had a 13% lower risk of intracerebral hemorrhage than those in the shortest RL group. Intracerebral hemorrhage is the deadliest type of stroke, occurring when blood vessels in the brain rupture.

Women in the group with the longest RL also had a 5% reduced risk of having an ischemic stroke — when the blood supply to the brain is cut off or reduced — compared to the group with the shortest.

The researchers also found that duration of oral contraceptive pill use, which is associated with increased estrogen levels, was associated with a lower risk of stroke.

Those with fewer stillbirths, miscarriages, and abortions were also less likely to develop a stroke.

“The association between reproductive longevity, endogenous/exogenous estrogens, and risk of stroke in women is poorly understood,” said Dr. Bharti Manwani, an assistant professor of vascular neurology at UTHealth Houston’s McGovern Medical School, who was not involved in the study Medical news today.

“Preclinical studies have shown that estrogen is a profound neuroprotective agent, while clinical trials of estrogen replacement therapy in postmenopausal women have shown no benefit,” she noted.

dr Alex Polyakov, associate professor and gynecologist at the University of Melbourne in Australia, who was also not involved in the study, agreed that the precise mechanisms behind estrogen’s effects on stroke risk are not fully understood.

He added: “Further research is needed to better understand the biological, behavioral and social factors that may contribute to the link.” Some possible mechanisms include estrogen’s ability to affect blood flow and blood clot formation, which may play a role in stroke risk.”

“Estrogen may also have protective effects on the brain and cardiovascular system. Estrogen is known to have a number of beneficial effects on the cardiovascular system, such as: B. improving blood lipid levels, reducing oxidative stress and promoting blood vessel health. The relationship between estrogen levels and risk of stroke is complex and can vary depending on various factors such as age, genetics, lifestyle and hormone replacement therapy.”

– dr Alex Polyakov

in the neurology The researchers concluded that cumulative estrogen exposure from reproductive factors could be a useful predictor of a woman’s risk of various types of postmenopausal stroke.

We have study author Dr. Peige Song, from the School of Public Health at Zhejiang University School of Medicine in Hangzhou, China, was asked about the limitations of the study.

She told us that “[s]Limitations of the study include potential recall bias in collecting reproductive factor information and an inability to control for other factors that may affect estrogen exposure and stroke risk, such as: B. Genetics, early life experiences and diet.”

“The major limitation of this study is that estrogen exposure was measured indirectly, rather than through direct blood levels,” says Dr. Adi Iyer, a neurosurgeon and neurointerventional surgeon at the Pacific Neuroscience Institute at Providence Saint John Health Center in Santa Monica, California, not involved in the study, also said MNT.

dr Polyakov added that because the study is an observational study, it can only establish correlation and not causation. He further noted that the study was only conducted on Chinese patients, so its results may not apply to people from other demographics.

“The implications of this study for the future of women’s health are very intriguing and further studies on the cerebrovascular protective value of higher lifetime estrogen exposure are needed,” Dr. George B. Branning, MD, MD, of Biote Medical Faculty, not affiliated with the study, said MNT.

“Although hormone replacement therapy [HRT] Typically recommended for patients seeking relief from symptoms such as hot flashes, night sweats, weight gain and mood swings, studies have shown that HRT is essential for lifelong functional bone health, sexual health and cognitive protection. These new study results suggest that we may be able to add stroke protection to this growing list of benefits,” he added.

dr Manwani agreed that it’s important to know that prolonged cumulative estrogen exposure reduces the risk of stroke in postmenopausal women. However, she found that age at the onset of puberty or menopause is beyond a woman’s control.

“Thus, it is important that clinicians risk stratify women with reduced estrogen exposure/reproductive lifespan and work towards aggressively controlling/treating their other modifiable vascular risk factors, e.g. B. high blood pressure, hyperlipidemia, atrial fibrillation, diabetes mellitus, smoking,” she explained.

“[These findings] also open up further debate about the role of estrogen in stroke. Is it good or bad? More studies of estrogen replacement therapy are needed to determine if increasing estrogen exposure through the use of hormone therapy would be beneficial,” she concluded.