Sex Differences in Stroke

by Women's Brain Health Initiative:Stroke is a significant public health concern, and is a leading cause of death and disability worldwide. According to the Global Burden of Diseases, Injuries and Risk Factors Study 2016 (GBD 2016), there were 13.7 million new stroke cases in 2016, including 5.5 million deaths – making stroke the second-largest cause of death worldwide.What is a Stroke?A stroke or “brain attack” occurs when blood flow to the brain is disrupted, killing off cells in affected parts of the brain. There are two types of stroke:Ischemic – when a blood clot cuts off blood flow to the brain; andHemorrhagic – when an artery in the brain ruptures or leaks blood.Ischemic strokes are much more common than hemorrhagic, but hemorrhagic strokes are more often fatal.While anyone can experience a stroke at any age, females are disproportionately affected by stroke compared to their male counterparts.Women experience more stroke events than men, and are less likely to recover. Elderly women, in particular, are especially vulnerable.Women Have More Stroke EventsThe risk of stroke is different for women and men, and varies depending on the age group. According to an academic review conducted by Alyana Samai and Dr. Sheryl Martin-Schild (published in 2015 in Vascular Health and Risk Management), middle-aged women are at decreased risk of stroke, and older women are at increased risk of stroke, compared to men.“Although the exact age ranges varied among the studies we reviewed, the general consensus is that women experience decreased risk for stroke compared to men while they are between the ages of roughly 40 and 75 years,” said Ms. Samai, currently the Director of Stroke Services at West Jefferson Medical Center in New Orleans.“But after the age of about 75, women become more likely than men to experience a stroke. In fact, they are at about 50% greater risk.” It is not surprising that women, as a collective, experience a higher number of stroke events than men, given their longer life expectancy and the higher incidence rate of stroke in the 75-and-over age bracket.More Women Die of Stroke, Have Worse Outcomes After Stroke, and are More Likely to Experience Recurrent StrokeVarious research studies indicate that more women die as a result of stroke than men. “Based on the estimates available when we conducted our review, women account for approximately 60% of stroke deaths,” noted Ms. Samai.Additionally, women who survive strokes tend to experience worse outcomes than men. “Our review found that after stroke, women are more likely to have more severe disabilities, need help with activities of daily living and walking, and be discharged to a nursing home than their male counterparts.”An earlier review conducted by L. Christine Turtzo and Louise D. McCullough – published in 2008 in Cerebrovascular Diseases – reported similar findings. In particular, the researchers noted that after an acute ischemic stroke, only 22.7% of women were fully recovered by six months after stroke compared to 26.7% of men. They also observed that women are more likely to be severely disabled when discharged (36.1% of women versus 24.2% of men).It is important to note that the differences between the sexes when it comes to outcomes after stroke may be, at least in part, the result of confounding factors (i.e. they might be explained by factors other than simply being female or male).For example, outcomes after stroke in women may be affected by the fact that women are generally older than men when they experience their first stroke (74.5 years on average versus 69.2 years for men), and they are more likely to live on their own at the time of the stroke, which may impact how quickly they receive medical attention.The researchers also found that among those between the ages of 40 and 69 who had experienced a first stroke, 22% of women experienced a recurrent stroke within five years, compared to 13% of men. Among those aged 70 years and older, 28% of women experienced a recurrent stroke within five years versus 23% of men. Whether women are receiving the medications proven to prevent a recurrent stroke at the same rate as men is a matter of debate, and an area in need of further research.What is Behind These Sex Differences?Given that women are disproportionately affected by stroke, researchers are very interested in determining the underlying cause (or causes) for these sex differences.It turns out that there are many risk factors for stroke that are unique to women. One group of researchers, led by Dr. Kathryn Rexrode, conducted a comprehensive review of the research to date in order to identify stroke risk factors that are unique to women. The results of their findings were published in 2018 in Stroke.“Although most strokes can be attributed to traditional vascular risk factors that occur in both women and men – including high blood pressure, high cholesterol, diabetes, smoking, and atrial fibrillation – there are several stroke risk factors that are specific to women,” explained Dr. Rexrode, Chief of the Division of Women’s Health at Brigham and Women’s Hospital and Associate Professor of Medicine at Harvard Medical School.“Our research revealed several factors that elevate stroke risk among women, including getting your first period before the age of ten years; experiencing menopause at a young age (i.e. under 45 years); low levels of the hormone dehydroepiandrosterone (DHEAS); and taking oral estrogen or combined oral contraceptives.”The researchers also reported that pregnancy and peripartum (a few weeks before and after childbirth) are periods of time associated with increased risk of stroke. In addition, complications of pregnancy – in particular, pregnancy-related hypertension, gestational diabetes, and pre-eclampsia – are associated with long-term risk of stroke.How to Lower Your Risk of Death or Disability from StrokeThere are two key ways that individuals can lower their risk of death or disability from stroke:

1. Do what you can to address any modifiable risk factors for stroke. According to the U.S. Centers for Disease Control and Prevention, up to 80% of strokes could be prevented by making healthy lifestyle choices and working with your doctor to control any health conditions that are known to increase stroke risk; and
2. Know the warning signs for stroke, and call 911 immediately if you experience any of them.

Modifiable Risk Factors There are certain stroke risk factors – such as gender, age, and family history – that cannot be controlled. However, there are many lifestyle-related risk factors that are within your power to control and can lower your risk of experiencing a stroke, including:

• Unhealthy diet;
• Cigarette smoking;
• Excessive alcohol and drug abuse;
• Physical inactivity; and
• Stress.

Not everyone who has a known risk factor will experience a stroke, and not everyone who is fortunate enough to have none of the risk factors will be assured of not having a stroke. “Many of the stroke risk factors that have been identified are extremely common, yet only a fraction of the women who have one or more of them will have a stroke in their lifetime,” emphasized Dr. Rexrode.“While women shouldn’t be excessively worried if they have a risk factor, it is helpful for them to be aware of any elevated risk,” continued Dr. Rexrode. “Hopefully that knowledge will motivate women to make the healthiest lifestyle choices possible to decrease their risk, and keep them alert for any possible stroke symptoms so that they can seek medical attention quickly if necessary.”Know the Warning Signs and Be FastMany stroke-focused organizations promote a quick checklist of six items to keep in mind when assessing whether you might be experiencing a stroke. The first letter of each item, when combined, spell the words “BE FAST” – a useful acronym that can help you remember the following:Balance: Are you having difficulties with balance or coordination?Eyes: Are you experiencing suddenly blurred or double vision, or a sudden loss of vision in one or both eyes?Face: When you smile, does one side of your face droop or does your face feel numb?Arms: Is one of your arms weak or numb? When you raise both arms, does one drift downward?Speech: Is your speech slurred or jumbled?Time: Call 911 or emergency medical services.If you are experiencing one or more of the abovementioned symptoms, then you need to call an ambulance immediately. Do not drive yourself to the hospital. Time is truly of the essence: individuals lose approximately two million brain cells every minute during a stroke. Knowing the warning signs and symptoms of a stroke may be the difference between recovery and disability.Source: MIND OVER MATTER V9