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One of the largest and longest-running efforts to evaluate the potential benefits of the Mediterranean-style diet in lowering risk of stroke found that the diet may be especially protective in women over 40 regardless of menopausal status or hormone replacement therapy, according to new research in the American Heart Association’s journal Stroke.
Researchers from the Universities of East Anglia, Aberdeen and Cambridge collaborated in this study using key components of a traditional Mediterranean-style diet including high intakes of fish, fruits and nuts, vegetables, cereal foods and potatoes and lower meat and dairy consumption.
Study participants (23,232 white adults, 40 to 77) were from the EPIC-Norfolk study, the United Kingdom Norfolk arm of the multicenter European Prospective Investigation into Cancer study. Over a 17-year period, researchers examined participants’ diets and compared stroke risk among four groups ranked highest to lowest by how closely they adhered to a Mediterranean style diet.
In participants, who most closely followed a Mediterranean-style diet, the reduced onset of stroke was:
- 17 percent in all adults;
- 22 percent in women; and
- 6 percent in men (which researchers said could have been due to chance).
“It is unclear why we found differences between women and men, but it could be that components of the diet may influence men differently than women,” said Ailsa A. Welch, Ph.D., study lead author and professor of nutritional epidemiology at the University of East Anglia, United Kingdom. “We are also aware that different sub-types of stroke may differ between genders. Our study was too small to test for this, but both possibilities deserve further study in the future.”
There was also a 13 percent overall reduced risk of stroke in participants already at high risk of cardiovascular disease across all four groups of the Mediterranean-diet scores. However, this was driven mainly by the associations in women who showed a 20 percent reduced stroke risk. This benefit appeared to be extended to people in low risk group although the possibility of chance finding cannot be ruled out completely.
“Our findings provide clinicians and the public with information regarding the potential benefit of eating a Mediterranean-style diet for stroke prevention, regardless of cardiovascular risk,” said Professor Phyo Myint, M.D., study co-author and former British Association of Stroke Physicians Executive Committee member, University of Aberdeen, Scotland.
“A healthy, balanced diet is important for everyone both young and old,” said Professor Ailsa Welch.
Researchers used seven-day diet diaries, which they said had not been done before in such a large population. Seven-day diaries are more precise than food-frequency questionnaires and participants write down everything they eat and drink over the period of a week.
“The American Heart Association recommends a heart-healthy and brain-healthy dietary pattern that includes a variety of fruits and vegetables, whole grains, low-fat dairy products, fish, poultry, beans, non-tropical vegetable oils and nuts and limits saturated fat, trans fat, sodium, red meat, sweets and sugar-sweetened beverages; this dietary pattern reduces risk factors and risk for heart disease and stroke, “said Eduardo Sanchez, M.D., MPH, the American Heart Association’s chief medical officer for prevention and chief of the Association’s Centers for Health Metrics and Evaluation, who was not a part of this study. “This study provides more evidence that supports AHA’s recommendation,” said Sanchez.
Story Source: American Heart Association. “Mediterranean-style diet may lower women’s stroke risk.” ScienceDaily. ScienceDaily, 20 September 2018. <www.sciencedaily.com/releases/2018/09/180920075854.htm>.
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There are two main treatments for stroke caused by a clot in a blood vessel in the brain. One treatment, mechanical thrombectomy, involves pulling the clot out with a specialized catheter that is inserted into the artery in the groin and guided by imaging to the clot. This procedure is only performed at hospitals that specialize in these techniques. The other treatment, which is more widely accessible, involves giving a patient a clot-busting drug that helps the body dissolve the clot.
Quick decision making on which treatment is best for which patient is critical because the clot deprives brain cells of oxygen causing them to die. For physicians, knowing which patients will benefit the most from the clot-buster Alteplase (also known as tPA) just got easier.
University of Calgary scientists with the Hotchkiss Brain Institute at the Cumming School of Medicine (CSM) have discovered that clots have different compositions and depending on where they are located in the brain, administering tPA can be almost as effective as thrombectomy given sufficient time.
“We’ve known that, when administered quickly, tPA can be effective in stroke, but until now, we didn’t realize how effective it can be and we didn’t understand the specific reasons why it works better in some cases than others,” says Dr. Bijoy Menon, MD, associate professor in the departments of Clinical Neurosciences, Radiology and Community Health Sciences at the CSM. “Our findings show that some clots are permeable, which allows the tPA to penetrate the blockage and dissolve it. We saw that within two hours, greater than 50 per cent of permeable blockages had dissolved.”
The UCalgary study led out of the Foothills Medical Centre is the largest of its kind to date, involving nearly 600 patients at 12 medical centres in five countries (Canada, the Czech Republic, South Korea, Spain and Turkey). The findings are published in JAMA.
“Despite earlier research on the benefit of using tPA, we know there is still some reluctance in the medical community to use it. These findings should provide physicians with definitive evidence on the value of giving patients tPA as soon as they’ve confirmed the stroke is due to a clot,” says Dr. Andrew Demchuk, MD, professor in the departments of Clinical Neurosciences and Radiology. “It’s critical that anyone showing symptoms of a stroke be given a CT-angiogram as soon as possible to confirm the blockage. The scan will guide whether tPA is likely to dissolve the clot and may inform whether the patient also needs thrombectomy.”
A CT-angiogram (computer tomography scan) is a common noninvasive diagnostic tool that allows physicians to see images of the blood vessels in the brain. Researchers found that clots in the carotid artery of the brain do not respond to tPA, and for these patients, thrombectomy is required.
“Strokes happen at anytime, anywhere. Knowing who needs thrombectomy can help physicians make better decisions on how to prioritize patient transfers to specialized centres for this procedure,” says Menon. “Data gathered in Europe showed that up to one-third of hospital transfers aren’t necessary.”
“Stroke is an important health care problem and one of the leading causes of death and disability worldwide,” says Dr. Brian H. Rowe, scientific director, Canadian Institutes of Health Research (CIHR) Institute of Circulatory and Respiratory Health, which supported this study. “Through continued scientific research, important discoveries like this one will improve our ability to match patients with the most effective treatment for this particular injury. This will help speed up recovery times, reduce the associated impacts such as paralysis, and it will improve patient outcomes and ultimately save lives.”
Drs. Menon and Demchuk add that for the science community these findings will help researchers better design studies that target dissolving the clot with new clot busting drugs or combination treatments.
Led by the Hotchkiss Brain Institute, Brain and Mental Health is one of six strategic research themes guiding the university towards its Eyes High goals. The strategy provides a unifying direction for brain and mental health research at the university and positions researchers to unlock new discoveries and treatments for brain health in our community.
Story Source: University of Calgary. “Critical differences in clots that cause a stroke: Findings will help inform physicians which treatment will work best for patients.” ScienceDaily. ScienceDaily, 12 September 2018. <www.sciencedaily.com/releases/2018/09/180912081219.htm>.
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About one third of patients who have suffered a stroke end up with low vision, losing up to half of their visual field. This partial blindness was long considered irreversible, but recent studies have shown that vision training after optic nerve and brain damage can help restore or improve vision. A new study published in the journal Clinical Neurophysiology reports on key mechanisms of vision restoration: attention.
Hemianopia is a decreased vision or blindness in half the visual field, usually as a consequence of stroke or trauma to the brain. It greatly reduces quality of life, affecting patients’ reading, driving and spatial navigation.
“Knowledge in this field is still rather fragmentary, but recent studies have shown that vision can be partially restored by vision training, which improves the deficient visual field sectors,” explains Prof. Bernhard Sabel, PhD, Director of the Institute of Medical Psychology at Magdeburg University, Germany, co-investigator of the study. “Neuroimaging evidence supports a possible role of attention in this vision restoration.”
The study confirmed this hypothesis by obtaining evidence from functional magnetic resonance imaging (fMRI) that visual training led to functional connectivity reorganization of the brain´s attentional network.
Seven chronic hemianopic patients with lesions of the visual cortex took part in vision rehabilitation training for five weeks. After the pre-tests all received training sessions lasting one and a half hours per day for six days per week for five weeks. Each training session, lasting about 60 minutes, was composed of six blocks with 120 training trials each, during which participants had to respond to specially designed visual stimuli on a computer monitor. The pre- and post-test included perimetry testing, contrast sensitivity testing and fMRI scanning one or two days before and after training, respectively. Each contrast sensitivity test consisted of 420 trials in six blocks. The visual rehabilitation training was performed with one eye open, which was randomly chosen, while the non-trained eye was covered with an opaque eye patch.
After training, the patients had significantly improved visual function at the training location, and fMRI showed that the training led to a strengthening of the cortical attentional network connections between the brain region of the right temporoparietal junction (rTPJ) and the insula and the anterior cingulate cortex (ACC).
“Our MRI results highlight the role of attention and the right TPJ activation as a component of vision restoration training in hemianopia,” notes lead investigator Yifeng Zhou, DSc, of the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, P.R. China, and State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China. “However, it is unclear whether the rehabilitation of attentional networks is the direct result of training or the result of the rebalancing of bottom-up sensory streams, which should be investigated in future studies.”
“This discovery that the brain´s attention network is a key mechanism in partially reversing blindness is an exciting advance in the field of restoring vision in the blind, and it opens up new avenues to design new therapies that are even more effective than current methods to help people with low vision or blindness,” concludes Prof. Sabel.
Story Source: Institute for Medical Psychology, Otto-v.-Guericke University Magdeburg. “Attention network plays key role in restoring vision after brain damage: New study highlights the role of attention as a component of vision restoration training in hemianopia.” ScienceDaily. ScienceDaily, 4 September 2018. <www.sciencedaily.com/releases/2018/09/180904114753.htm>.
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People who have had a stroke are around twice as likely to develop dementia, according to the largest study of its kind ever conducted.
The University of Exeter Medical School led the study which analysed data on stroke and dementia risk from 3.2 million people across the world. The link between stroke and dementia persisted even after taking into account other dementia risk factors such as blood pressure, diabetes and cardiovascular disease. Their findings give the strongest evidence to date that having a stroke significantly increases the risk of dementia.
The study builds on previous research which had established the link between stroke and dementia, though had not quantified the degree to which stroke actually increased dementia risk. To better understand the link between the two, researchers analysed 36 studies where participants had a history of stroke, totalling data from 1.9 million people. In addition, they analysed a further 12 studies that looked at whether participants had a recent stroke over the study period, adding a further 1.3 million people. The new research, published in the leading dementia journal Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, is the first meta-analysis in the area.
Dr Ilianna Lourida, of the University of Exeter Medical School, said: “We found that a history of stroke increases dementia risk by around 70%, and recent strokes more than doubled the risk. Given how common both stroke and dementia are, this strong link is an important finding. Improvements in stroke prevention and post-stroke care may therefore play a key role in dementia prevention.”
According to the World Health Organisation, 15 million people have a stroke each year. Meanwhile, around 50 million people globally have dementia – a number expected to almost double ever 20 years, reaching 131 million by 2050.
Stroke characteristics such as the location and extent of brain damage may help to explain variation in dementia risk observed between studies, and there was some suggestion that dementia risk may be higher for men following stroke.
Further research is required to clarify whether factors such as ethnicity and education modify dementia risk following stroke. Most people who have a stroke do not go on to develop dementia, so further research is also needed to establish whether differences in post-stroke care and lifestyle can reduce the risk of dementia further.
Dr David Llewellyn, from the University of Exeter Medical School, concluded: “Around a third of dementia cases are thought to be potentially preventable, though this estimate does not take into account the risk associated with stroke. Our findings indicate that this figure could be even higher, and reinforce the importance of protecting the blood supply to the brain when attempting to reduce the global burden of dementia.”
Story Source: University of Exeter. “Stroke doubles dementia risk, concludes large-scale study.” ScienceDaily. ScienceDaily, 31 August 2018. <www.sciencedaily.com/releases/2018/08/180831083542.htm>.
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Postmenopausal factors may have an impact on the heart-protective qualities of high-density lipoproteins (HDL) — also known as ‘good cholesterol’ — according to a study led by researchers in the University of Pittsburgh Graduate School of Public Health.
The findings, published today in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association (AHA), indicate that this specific type of blood cholesterol may not translate into a lowered risk of cardiovascular disease in older women — bringing into question the current use of HDL cholesterol in a common equation designed to predict heart disease risk, particularly for women.
HDL is a family of particles found in the blood that vary in sizes and cholesterol contents. HDL has traditionally been measured as the total cholesterol carried by the HDL particles, known as HDL cholesterol. HDL cholesterol, however, does not necessarily reflect the overall concentration, the uneven distribution, or the content and function of HDL particles. Previous research has demonstrated the heart-protective features of HDL. This good cholesterol carries fats away from the heart, reducing the build-up of plaque and lowering the potential for cardiovascular disease.
“The results of our study are particularly interesting to both the public and clinicians because total HDL cholesterol is still used to predict cardiovascular disease risk,” said lead author Samar R. El Khoudary, Ph.D., M.P.H., F.A.H.A., associate professor in Pitt Public Health’s Department of Epidemiology. “This study confirms our previous work on a different group of women and suggests that clinicians need to take a closer look at the type of HDL in middle-aged and older women, because higher HDL cholesterol may not always be as protective in postmenopausal women as we once thought. High total HDL cholesterol in postmenopausal women could mask a significant heart disease risk that we still need to understand.”
El Khoudary’s team looked at 1,138 women aged 45 through 84 enrolled across the U.S. in the Multi-Ethnic Study of Atherosclerosis (MESA), a medical research study sponsored by the National Heart, Lung and Blood Institute of the National Institutes of Health (NIH). MESA began in 1999 and is still following participants today.
The study points out that the traditional measure of the good cholesterol, HDL cholesterol, fails to portray an accurate depiction of heart disease risk for postmenopausal women.
Women are subject to a variety of physiological changes in their sex hormones, lipids, body fat deposition and vascular health as they transition through menopause. The authors are hypothesizing that the decrease of estrogen, a cardio-protective sex hormone, along with other metabolic changes, can trigger chronic inflammation over time, which may alter the quality of HDL particles.
“We have been seeing an unexpected relationship between HDL cholesterol and postmenopausal women in previous studies, but have never deeply explored it,” said El Khoudary. Her study looked at two specific measurements of HDL to draw the conclusion that HDL cholesterol is not always cardio-protective for postmenopausal women, or not as ‘good’ as expected.
The number and size of the HDL particles and total cholesterol carried by HDL particles was observed. The study also looked at how age when women transitioned into postmenopause, and the amount of time since transitioning, may impact the expected cardio-protective associations of HDL measures.
The harmful association of higher HDL cholesterol with atherosclerosis risk was most evident in women with older age at menopause and who were greater than, or equal to, 10 years into postmenopause.
In contrast to HDL cholesterol, a higher concentration of total HDL particles was associated with lower risk of atherosclerosis. Additionally, having a high number of small HDL particles was found beneficial for postmenopausal women. These findings persist irrespective of age and how long it has been since women became postmenopausal.
On the other hand, large HDL particles are linked to an increased risk of cardiovascular disease close to menopause. During this time, the quality of HDL may be reduced, increasing the chance for women to develop atherosclerosis or cardiovascular disease. As women move further away from their transition, the quality of the HDL may restore — making the good cholesterol cardio-protective once again.
“Identifying the proper method to measure active ‘good’ HDL is critical to understanding the true cardiovascular health of these women,” said senior author Matthew Budoff, M.D., of Los Angeles Biomedical Research Institute.
El Khoudary recently was awarded funding from the National Institute on Aging to expand upon this research work. Her goal is to continue understanding the link between quality of good cholesterol over the menopause transition and women’s risk of cardiovascular disease later in life. She also seeks to examine the biological mechanisms that contribute to quality change of good cholesterol, so that the cardio-protective contribution of good cholesterol to postmenopausal women’s health can be clarified, which would impact guidelines for screening and treatment.
Additional authors on this study are Indre Ceponiene, M.D., Ph.D., of Harbor-UCLA Medical Center and Lithuanian University of Health Sciences; Saad Samargandy, M.P.H., of Pitt; James H. Stein, M.D., and Matthew C. Tattersall, D.O., M.S., both of University of Wisconsin; Dong Li, Ph.D., of Los Angeles Biomedical Research Center in Torrance CA.
This research was funded by NIH grants R01 HL071739, N01-HC-95159, N01-HC-95160, N01-HC-95161, N01-HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, N01-HC-95169, UL1-TR-000040, UL1 TR 001079 and UL1-RR-025005; and a grant from Quest Diagnostics.
Story Source: Chicago, University of Pittsburgh Schools of the Health Sciences. “‘Good cholesterol’ may not always be good.” ScienceDaily. ScienceDaily, 19 July 2018. <www.sciencedaily.com/releases/2018/07/180719085420.htm>.
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Four out of ten patients with atrial fibrillation but no history of stroke or transient ischaemic attack have previously unknown brain damage, according to the first results of the Swiss Atrial Fibrillation Cohort Study (Swiss-AF) presented today at ESC Congress 2018.
“Our results suggest that clinically unrecognised brain damage may explain the association between dementia and atrial fibrillation in patients without prior stroke,” said Co-Principal Investigator Professor David Conen of McMaster University, Hamilton, Canada.
Patients with atrial fibrillation have a significantly increased risk of stroke, which is why most are treated with blood thinners (oral anticoagulation). This increased stroke risk is probably the main reason why patients with atrial fibrillation also face an increased risk of cognitive dysfunction and dementia. However, the relationship between atrial fibrillation and dementia has also been shown among patients without prior strokes, meaning that additional mechanisms have to be involved.
Clarifying the mechanisms by which atrial fibrillation increases the risk of cognitive dysfunction and dementia is a first step towards developing preventive measures.
Swiss-AF is a prospective, observational study designed to pinpoint the mechanisms of cognitive decline in patients with atrial fibrillation.2 This analysis investigated the prevalence of silent brain damage in atrial fibrillation patients.
The study enrolled 2,415 patients aged over 65 years with atrial fibrillation between 2014 and 2017 from 14 centres in Switzerland. All patients without contraindications underwent standardised brain magnetic resonance imaging and the images were analysed in a central core laboratory. Scans were available in 1,736 patients. Of those, 347 (20%) patients had a history of stroke and/or transient ischaemic attack and were excluded from the analysis.
The final analysis included 1,389 patients with atrial fibrillation but no history of stroke or transient ischaemic attack. The average age of participants was 72 years, and 26% were women. The scans showed that 569 (41%) patients had at least one type of previously unknown brain damage: 207 (15%) had a cerebral infarct, 269 (19%) had small bleeds in the brain (microbleeds), and 222 (16%) had small deep brain lesions called lacunes.
“Four in ten patients with atrial fibrillation but no history of stroke or transient ischaemic attack had clinically unrecognised ‘silent’ brain lesions,” said Professor Conen. “This brain damage could trigger cognitive decline.”
Most study participants (1,234; 89%) were treated with oral anticoagulants. Co-Principal investigator Professor Stefan Osswald of University Hospital Basel, Switzerland, noted that the cross-sectional analysis looked at the data at a single point in time and cannot address the question of whether the cerebral infarcts and other brain lesions occurred before or after initiation of oral anticoagulation. But he said: “The findings nevertheless raise the issue that oral anticoagulation might not prevent all brain damage in patients with atrial fibrillation.”
Professor Conen said: “All Swiss-AF participants underwent extensive cognitive testing. These data will be analysed to see whether patients with silent brain lesions also have impaired cognitive function.” Collaborations with other study groups will help to sort out whether these findings are specific to patients with atrial fibrillation.
Story Source:”Four out of 10 patients with atrial fibrillation have unknown brain damage.” ScienceDaily. ScienceDaily, 26 August 2018. <www.sciencedaily.com/releases/2018/08/180826120744.htm>.