Detecting strokes earlier using a phone app; Mediterranean diet and Alzheimer's
June 1, 2021 | View PDF
Preventing strokes with a phone app
It may soon be possible to detect atrial fibrillation with your phone. About one-third of ischemic strokes, those triggered by blood clots, are caused by atrial fibrillation, which is the most common heart rhythm disorder. Since many people don’t have symptoms and are unaware of its presence, atrial fibrillation often goes undiagnosed. In some cases, a stroke is the first sign that a person has the disorder. American Indians are more at risk for atrial fibrillation than people in other racial and ethnic groups. As a population, American Indians also have substantially higher rates of obesity, diabetes and high blood pressure, which are all risk factors for atrial fibrillation.
Researchers are reporting in the Journal of the American Heart Association that a smartphone-based electrocardiogram (ECG) screening accurately detected previously unknown atrial fibrillation in American Indians, and more than half who were diagnosed with the irregular heart rhythm were younger than the recommended screening age of 65. Individuals with atrial fibrillation are five times more likely to suffer stroke than those without atrial fibrillation.
“We know the risk of atrial fibrillation is high in people who are from racial and ethnic groups, especially among American Indians, so we wanted to see if we could identify silent atrial fibrillation,” said lead study author Dr. Stavros Stavrakis, a cardiologist at the Heart Rhythm Institute of the University of Oklahoma Health Sciences Center in Oklahoma City, Oklahoma. “Systemic screening among American Indians has never been done before, and the true rate of atrial fibrillation in this population is unknown,” Dr. Stavrakis said.
Researchers enrolled 1,019 American Indians, ages 50 and older. In this study, 63% were female and investigators compared the ECG results of the screened participants to the results of a control group. The control group included 1,267 American Indian adults, ages 50 and older, who received care at their tribal clinics during the same time period but did not receive the mobile-based ECG screening.
Of the 1,019 participants who received the mobile-based ECG screening, atrial fibrillation was found in 15 patients (1.5%). In contrast, only four of the 1,267 (0.3%) patients in the control group (standard care, based on clinical symptoms alone) were diagnosed with atrial fibrillation. About half of those diagnosed with atrial fibrillation by mobile-based ECG (eight of 15 patients) were younger than 65.
“Our study shows that we have a very simple and accurate method to screen and diagnose atrial fibrillation that is easy to implement at tribal clinics,” said Dr. Stavrakis. “This widely-available, low-cost approach has real potential to improve health outcomes among American Indians.”
American Indians develop cardiovascular diseases at earlier ages than the national average. More than one-third of deaths attributed to cardiovascular disease in American Indians occur before the age of 65, which is the recommended age to begin atrial fibrillation screening according to guidelines from the U.S. Preventive Services Task Force.
“In a targeted, high-risk population such as American Indians, our results showed screening at a younger age found many cases of atrial fibrillation that would have been missed following current age recommendations,” said Dr. Stavrakis. “We have the potential to improve outcomes in this population by initiating early treatment.”
Dietary changes may have brain benefits
Alzheimer’s disease is caused by protein deposits in the brain and the rapid loss of brain matter, however a Mediterranean diet rich in fish, vegetables and olive oil may be protective. In Alzheimer’s disease, neurons in the brain die. Largely responsible for the death of neurons are beta-amyloid proteins, which form clumps (plaques) between neurons. This leads to Alzheimer’s symptoms such as memory loss, disorientation, agitation and challenging behavior.
Scientists at the memory clinic of the University Hospital Bonn in Germany now have found that a regular Mediterranean-like dietary pattern with relatively more intake of vegetables, legumes, fruit, cereals, fish and monounsaturated fatty acids, such as from olive oil, may protect against protein deposits in the brain and brain atrophy. This diet has a low intake of dairy products, red meat, and saturated fatty acids.
A total of 512 subjects with an average age of around 70 years took part in the study. The volunteers were divided into two groups: 169 participants were cognitively healthy, while 343 were identified as having a higher risk of developing Alzheimer’s disease due to memory impairment, mild cognitive impairment (MCI) and other factors.
“People in the second half of life have constant eating habits. We analyzed whether the study participants regularly eat a Mediterranean diet, and whether this might have an impact on brain health,” said study investigator Professor Michael Wagner.
The participants first filled out a questionnaire in which they indicated which portions of 148 different foods they had eaten in the past months. Those who frequently ate healthy foods typical of the Mediterranean diet, such as fish, vegetables and fruit, and only occasionally consumed foods such as red meat, scored highly on a scale.
The scientists investigated brain atrophy. They performed brain scans with magnetic resonance imaging (MRI) to determine brain volume. All the participants underwent various neuropsychological tests in which cognitive abilities such as memory functions were examined. The researchers found that those who ate an unhealthy diet had higher levels of these biomarkers in the cerebrospinal fluid than those who regularly ate a Mediterranean-like diet.
In the memory tests, the participants who did not adhere to the Mediterranean diet also performed worse than those who regularly ate fish and vegetables.
“There was also a significant positive correlation between a closer adherence to a Mediterranean-like diet and a higher volume of the hippocampus. The hippocampus is an area of the brain that is considered the control center of memory. It shrinks early and severely in Alzheimer’s disease,” said lead study author Tommaso Ballarini, PhD, a postdoctoral fellow in Michael Wagner’s research group.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at firstname.lastname@example.org.