Published on: October 28, 2018
by Women’s Brain Health Initiative:
Many women may not realize that heart disease and stroke are the leading causes of premature death for women in Canada. In fact, heart disease and stroke kill 31,000 women in Canada annually, according to the Canadian Heart and Stroke Foundation (“Heart & Stroke”). Two new reports published by the foundation are putting both women and their healthcare providers on alert.
WOMEN’S HEART HEALTH – LIKE WOMEN’S BRAIN HEALTH – IS “UNDER-RESEARCHED, UNDER-DIAGNOSED, AND UNDER-TREATED.
“It’s shocking that we are so far behind in our understanding of women’s hearts,” says Yves Savoie, CEO of Heart & Stroke, “and that new knowledge is so slow to reach the bedside.” For decades, specific therapies were tested in controlled studies on primarily middle-aged, white male subjects. The assumption was that what worked for men, also worked for women, and what was learned “formed the basis of clinical guidelines, diagnostic procedures and therapies that, even today, are widely used for both men and women.”
While overall female hearts appear the same as male hearts, “there are important differences that are irrefutable and still poorly understood,” says Dr. Karin Humphries, scientific director of the BC Centre for Improved Cardiovascular Health.
SEX AND GENDER BLINDERS HAVE LED TO TOO MANY WOMEN DYING UNNECESSARILY.
SEX DIFFERENCES IN THE CARDIOVASCULAR SYSTEM
One of the reasons why women’s heart health knowledge is vastly behind that of men’s is because of the actual physiological differences in men’s and women’s hearts. “Women’s vessels tend to be smaller, their hearts are smaller,” notes Dr. Patrice Lindsay, Director of Stroke at Heart & Stroke. This means that when women experience heart attack symptoms, their symptoms might be different than their male counterparts.
As with men, women’s most common heart attack symptom is chest pain or discomfort. Women’s symptoms, however, tend to be subtler and more ambiguous. Women often experience less severe chest pain than men, which may be described as pressure or tightness rather than the so-called “Hollywood heart attack” (chest-clutching, crushing pain radiating down the arm and up to the jaw).
Women are also more likely than men to exhibit symptoms unrelated to chest pain such as pain or discomfort in one or both arms, the neck, back, jaw, or stomach, as well as shortness of breath (with or without chest discomfort), unusual fatigue and/or nausea, vomiting, or lightheadedness. These symptoms may develop slowly over hours or days, and even come and go.
These differences in symptoms can impact the timely identification of heart disease in women, first by the women themselves and later by health professionals. According to a retrospective study published in Circulation,
EARLY HEART ATTACK SIGNS WERE MISSED IN 78% OF WOMEN in the study group, even though these signs occurred repeatedly over a period of weeks or months.
When symptoms are subtle, they are easier to overlook, misdiagnose, or ignore altogether. Women often incorrectly assume that their symptoms are the result of non-life-threatening conditions such as acid reflux, the flu, or normal aging. Consequently, women tend to wait much longer than men before seeking emergency medical services, putting women at greater risk for adverse outcomes.
One study found that the median time women waited before seeking care when experiencing heart attack symptoms was 53.7 hours, compared to just 15.6 hours for men. Other studies have suggested that the median delay times range from two to five hours – exceeding the American Heart Association’s recommendation by hours, not minutes.
Once women have arrived at the hospital, it can take them longer to be diagnosed than men, or their condition may be missed entirely and they are sent home.
MANY OF THE SCREENING TOOLS USED TO DIAGNOSE A HEART ATTACK WERE DEVELOPED AND TESTED ON MEN, AND MAY OVERLOOK HEART DISEASE OR A HEART ATTACK IN A WOMAN.
For instance, “women tend to have disease in the small vessels of their heart, while men are more likely to have disease in their major coronary arteries,” explains Dr. Tara Sedlak, director of the Leslie Diamond Women’s Heart Health Centre in Vancouver.
“The angiogram – the standard diagnostic tool used to detect heart disease – images the major coronary arteries. It does not capture disease in the smaller coronary arteries (microvascular disease).” And when a classic heart health test is not detecting a problem, women might be sent home with an anxiety or menopause-related diagnosis, rather than heart attack or stroke, notes Dr. Lindsay.
What’s more, some “medications don’t work as well for women versus men,” meaning that even when women receive a correct diagnosis, the treatment is not necessarily as effective as it is for men. In fact, certain drugs have been found to cause harmful and even fatal side effects in women, according to Heart & Stroke.
RESEARCH BIAS (AND WHAT’S CHANGING)
There are a multitude of factors that have led to the inequality women still face today regarding their heart health. Historically, research into the testing and treatment of heart disease has had more male participants than female, which began because of safety concerns involving women in drug development (most notably, as a result of the “thalidomide disasters” in the early 1960s, in which a drug used by pregnant women caused major birth defects in a large number of newborns).
Dr. Lindsay says that she does not believe that this disparity was a “deliberate attempt by anyone to bias women,” but there has been hesitation on the part of both the research establishment and potential women participants due to this history.
In 1997, Health Canada issued revised guidelines, recommending that women be included in research and clinical trials in order to better understand sex differences. However, over two decades later, researchers are still encountering roadblocks when looking to find female participants for studies and clinical trials.
Structurally, there are exclusions for certain women, says Dr. Lindsay. For example, women of childbearing age, or those who are pregnant or potentially pregnant, are often excluded, usually for good reason because testing new drugs obviously carries a risk. Often, there is also an age cut-off, which “automatically wipes out a lot of older women” who could be trialling drugs, says Dr. Lindsay, and sometimes this exclusion is unwarranted.
Additionally, on an individual level, women tend to be more risk averse, says Dr. Lindsay, which means that left to their own choices, men tend to volunteer more for research, than do women. Educating women about participating in research trials is important, then, so that sex-specific results make their way into research findings.
BE YOUR OWN ADVOCATE
“Importantly, major research funding bodies, including Heart & Stroke and the Canadian Institutes of Health Research (CIHR), are now requiring that sex and gender be defined and considered in research findings and reporting,” says Dr. Lindsay. CIHR is also offering training resources that educate researchers about the importance of women-specific testing and results. It is a “multi-pronged approach” for change, she says.
While progress has been made recently, it has not been “nearly fast enough to equitably protect women’s hearts,” says Savoie. “The challenge is to accelerate the pace of change, to gather new knowledge and translate it into better and safer heart health care for women.” It is therefore important for women to be their own advocates. Do not be afraid to ask. If your symptoms are not normal for you, you will know that. We are the only ones who truly know what is usual or unusual for our bodies.
IT ALSO HELPFUL TO KNOW THAT THERE ARE A FEW KEY MOMENTS IN A WOMAN’S LIFETIME THAT ARE MAJOR HEART AND STROKE RISK MOMENTS.
The first is pregnancy, says Dr. Lindsay, which is the “first heart stress test for women.” Due to hormonal changes, some women experience high blood pressure that can lead to preeclampsia or pregnancy-
related diabetes. Experiencing these conditions during pregnancy means that you may have a much higher risk of suffering from heart disease earlier in life. The second major heart stress test is menopause. After menopause, says Dr. Lindsay, risk of heart disease and stroke increase. Hormone replacement therapy is a double-edged sword, because research shows that while it is protective for heart disease, it actually increases the risk of stroke. Researchers are still trying to determine exactly how women’s hormonal changes impact their heart and stroke risk.
PARALLELS WITH ALZHEIMER’S DISEASE RESEARCH
Since we know that brain health is very much connected to heart health (several studies have shown a link between the two, including one in 2016 from the American Heart Association that found that older adults who had healthier cardiovascular systems had less decline over time in brain processing speed, memory, and executive functioning), this lag in understanding women’s cardiovascular needs necessarily extends to brain health as well.
As is the case for our hearts, we now know that “there are fundamental differences in the way the brain is organized in terms of connectivity or how the parts of the brain talk to each other, between men and women,” says Dr. Pauline Maki, Professor of Psychiatry and Psychology and Associate Director of the Center for Research on Women and Gender at the University of Illinois at Chicago. This means that MEN’S AND WOMEN’S BRAINS ARE STRUCTURALLY AND FUNCTIONALLY DIFFERENT.
However, the divergence between men’s and women’s brains – and their experiences of diseases of the brain – is not yet well established.
For instance, researchers have known for nearly two decades that women with the APOE 4 gene are more likely than men with the gene to develop dementia, but still no one understands why this is the case. “[T]he field largely ignored it,” says Dr. Maki, “because the field ignored sex differences more generally.”
Much more research needs to be conducted in order to understand how sex and gender differences impact an individual’s Alzheimer’s disease (AD) risk. In fact, Dr. Maki and her colleagues from The Society for Women’s Health Research Interdisciplinary Network on AD wrote a paper, published in the June 2018 issue of Alzheimer’s and Dementia, that outlines twelve priority research areas for clinical research in AD regarding sex and gender, including looking at “potential sex-specific risk factors for AD,” like pregnancy or testosterone loss, and paying attention to sex and gender differences “in developing AD therapeutics, from preclinical to clinical studies, and in the design of clinical trials.”
One line of research that is relatively new but is showing quite a bit of promise examines the impact of certain hormones, such as estrogen, on a woman’s brain. “There’s a compelling body of research to suggest that women’s brains undergo a pretty considerable change in function and structure during menopause, and people are just beginning to look at whether that critical female-specific life event might in some way set up, at least a proportion of women, for Alzheimer’s disease later in life,” says Dr. Maki.
Some women show a decrease in memory functioning when they go through menopause, as evidenced by memory tests that are also used to diagnose AD. What’s more, 80% of women experience hot flashes during menopause, and Dr. Maki and her colleagues have found that “when you measure them objectively with monitors, they correlate significantly with decreases in memory performance, decreases in brain function, and increases in tiny, little structural changes in the brain that look like very small strokes.”
Treating hot flashes, then, is one avenue of treatment that Dr. Maki and her colleagues are currently exploring. Women in menopause also experience sleep-related disturbance, says Dr. Maki, and sleep disruptions “impact the brain’s ability to clear out toxins” – so that is another hormonal factor that needs further researching, examination, and treatment in individual women. Of course, as Dr. Maki observes, all women go through menopause and not all of them develop AD, so more work needs to be done to understand why, for some women, this reproductive event could be the “perfect storm.”
Similar to heart research, the tide in women’s brain research is also shifting. Major U.S. associations like the Alzheimer’s Disease Association and the National Institute on Aging are actively soliciting grant applications that focus on sex- and gender-specific manifestations of AD. This year’s Alzheimer’s Association International Conference held a featured research session on hormonal contributions to dementia risk in women. “I’m happy to say the field is finally coming around,” says Dr. Maki.
PREVENTION STRATEGIES FOR WOMEN: DOS AND DON’TS
It is important for women to be proactive and to take better care of their health, including making themselves a priority.
TIPS FROM DR. PATRICE LINDSAY:
TIPS FROM DR. PAULINE MAKI:
Source: MIND OVER MATTER V7
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