The vision was ambitious: Persuade thousands of Dallas County residents to participate in a long-term study to investigate heart health.

The logistics were challenging: Go door to door to build a diverse cohort and then collect medical histories, blood work, and imaging using the most sophisticated equipment available.

The results, compiled over two decades at UT Southwestern Medical Center, have been life-altering.

Twenty-five years since its inception, the Dallas Heart Study (DHS) is recognized as one of the leading population-based studies of heart health in the U.S. It has spawned more than 230 research papers and produced major findings that have guided advancements in how cardiovascular disease, hypertension, and heart failure are treated.

Among the top breakthroughs, researchers discovered a gene mutation linked to very low levels of LDL, or bad cholesterol, leading to a new class of drugs for patients who cannot control cholesterol with statins.

"The Dallas Heart Study has had a tremendous impact nationally and internationally on the way we understand heart disease," said James de Lemos, M.D., Professor of Internal Medicine and Chief of the Division of Cardiology at UT Southwestern and one of the study's Principal Investigators.

"The DHS has really been ahead of its time," added Amil Shah, M.D., M.P.H., Professor of Internal Medicine in the Division of Cardiology, who was recruited to UT Southwestern from Harvard Medical School in 2023 to take over as the study's Director. "The founders were thinking about metabolic dysfunction, fat accumulation in vital organs, and all of the most relevant drivers of cardiovascular disease before they really hit the mainstream."

Today the DHS is expanding its reach to explore the brain as well as the heart. The newest round of research, called the Dallas Hearts and Minds Study, is examining the impact of aging on the cohort, which has collectively grown older. About 1,500 participants have been enrolled in the new phase and are undergoing a series of evaluations and tests including cardiac ultrasounds, both at rest and during exercise; cardiopulmonary exercise tests; brain MRIs; full-body MRIs to quantify body fat and its location; and magnetoencephalography (MEG), which maps brain activity. Additionally, participants are being assessed for cognitive ability as well as pain and subtypes of pain during physical activity.

"The future of cardiovascular research, particularly at UT Southwestern, is incredibly bright," said Dr. de Lemos. "The DHS and now the Dallas Hearts and Minds Study provide a pathway for how collaborative teams can work together to address health challenges as people get older."

Taking on the No. 1 killer

Heart disease is the No. 1 cause of death in the United States and globally, and in Dallas County, mortality is even more pronounced among Black men and women.

Recognizing this, researchers led by Helen Hobbs, M.D., Professor of Internal Medicine in UTSW's Eugene McDermott Center for Human Growth and Development, and the late Ronald Victor, M.D., an expert in hypertension, drafted a proposal to the Donald W. Reynolds Foundation, ultimately securing a decadelong grant that would take advantage of Dallas County's diverse population and UT Southwestern's innovative approach to research, incorporating new technologies and multidisciplinary teams.

The Dallas Heart Study was born.

At the time, UT Southwestern was well known for its excellence in basic science, but its scientists had never led a population-based study. Dr. Hobbs saw the Dallas Heart Study as a chance to blend UTSW's scientific expertise with clinical research to address a major community problem. More than 6,000 residents between the ages of 35 and 55 were signed up, targeted in select ZIP codes based on their demographic makeup, with the cohort weighted heavily with Black participants to reflect Dallas' diversity.

"We wanted the study to be large and representative, and we wanted to be able to probe the mechanism of disease using genetics and hospital-based sub-studies," Dr. Hobbs said.

The latest iteration, conducted over the last three years, has shifted the focus to late-life issues, such as cognition, since participants are now all over 55, with some approaching 80.

Gene mutations and barbershops

Early results were groundbreaking. The first round of testing yielded information that led to major breakthroughs for treating both atherosclerosis and hypertension.

Dr. Hobbs, working with her colleague, Jonathan Cohen, Ph.D., Professor in the Eugene McDermott Center for Human Growth and Development, found that participants with extremely low LDL levels carried mutations in the PCSK9 gene. This insight led to FDA-approved PCSK9 inhibitors in 2015 -- a major new class of cholesterol-lowering drugs.

"This type of finding is really the jewel in the crown of what these cohorts are designed to be able to do, and it's impressive that the DHS is relatively unique in its achievement of that," Dr. Shah said. "In less than two decades, to move from this fundamental discovery to clinical translation to having an entire class of drugs to allow high-risk patients to live healthier lives is as rich a success story as one could hope for."

The DHS also uncovered alarming rates of untreated hypertension in Black men. To reach this population, Dr. Victor piloted blood pressure screenings in barbershops. Customers identified with hypertension received treatment, resulting in significant blood pressure reductions. The model has since become a national intervention and has been adapted to other awareness programs, such as screenings for diabetes and prostate cancer.

Over the years, other significant findings from DHS research include:

• Lowering cholesterol early in life is far more protective than starting in middle age.
• The location of body fat strongly influences diabetes and heart disease risk.
• Simple blood tests can predict future cardiac events, even in people without symptoms.

'A sense of relief'

Eleanor Bergeron, 78, said she signed up for the initial study after someone from UTSW knocked on her door in Duncanville. She thought it was a good opportunity and, for the past 25 years, she has provided annual assessments of her health and come to UTSW for periodic testing. About a year and a half ago, she had brain scans for the Dallas Hearts and Minds Study and was scheduled for heart imaging.

Her husband, Dennis, joined the study several years later when he became involved in research investigating the impact of exercise on the heart. He ran on a treadmill and underwent cardiac catheterization, where he watched his heartbeat on a monitor.

Fortunately, the testing hasn't revealed any cardiac problems for either of them. But they say being part of a medical study has been meaningful.

"What it did for me was made me want to exercise more," said Mr. Bergeron, 80. "It has been a positive experience. What they're doing is pretty extensive."

Leo Fair, 63, who works in aircraft maintenance for Southwest Airlines, joined in 2009 after learning about the study from his sister, who was already involved. He said their mother died of a heart attack when she was 50, so he saw the study as an opportunity to prevent history from repeating for his family.

"My heart was good, and I was happy to know that," he said. "It gave me a sense of relief."

Mr. Fair has remained in the study even after moving to Florida in 2015, and he returns to Dallas periodically for testing - most recently a full-body MRI about a year and a half ago. It gives him peace of mind to confirm that he doesn't have a heart condition, and a sense of purpose knowing he's helping other people.

"That's a treasure," he said.

Positioned for the future

Dr. Shah said the sustained success of the Dallas Heart Study over 25 years can be attributed to a number of factors.

"The DHS has really embraced new technologies," he said, "particularly in engaging with our participants."

The volume of high-quality imaging has also been innovative. Very few studies provide the level of detail of the heart and body captured by the DHS, Dr. Shah explained. That emphasis on utilizing the latest technology will continue in the current phase with testing in the MEG facility, which will produce one of the nation's largest brain-mapping datasets using this sophisticated, noninvasive technology.

Another strength has been the diversity of the cohort, which has allowed researchers to investigate health disparities that have resulted in higher rates of heart disease, at younger ages, in Black men and women. Because of the long-term nature of the study and its relationship with participants, researchers have been able to collect data on subclinical changes and social determinants of health, which could lead to better health in the community, Dr. Shah said.

Internally, the Dallas Heart Study has accelerated clinical research at UT Southwestern and elevated the Division of Cardiology by attracting a team of highly talented physician-scientists who wanted to be involved in the research, said Dr. de Lemos, who himself was lured back to UT Southwestern from Harvard 25 years ago by the promise of the DHS.

"It's almost hard to overstate how important this study has been to the evolution of cardiology at UT Southwestern," Dr. de Lemos said.

"The story of cardiology at UTSW in 2025 is really the story of the Dallas Heart Study," he continued. "It has transformed the entire institution, and so many people have built their academic careers from this study and are now internationally known scientists."

From his perspective, Mr. Fair said participating in the Dallas Heart Study has been very meaningful and he hopes it continues for another 25 years.

"There's a lot of sickness in this world," he said. "I'm happy to play my part because I know some good is coming out of it. Working together, we're saving someone's life."

Expanding from hearts to minds

Building on the legacy of the Dallas Heart Study, the new Dallas Hearts and Minds Study (DHMS) is exploring how aging affects both the heart and the brain. The expansion was the vision of Jarett Berry, M.D., a world-renowned epidemiologist and the study's first Principal Investigator, who is now Chairman of Medicine at UT Tyler School of Medicine.

With original participants now in their late 50s and beyond, researchers are uniquely positioned to track how risk factors across a lifetime influence aging. The study seeks to understand why some individuals experience cognitive decline or functional impairments, while others age more robustly.

In addition to brain imaging and cognitive assessments, DHMS evaluates exercise capacity, balance, pain, and cardiovascular progression, providing a comprehensive picture of how the heart and brain interact over time.

Importantly, this emphasis on brain health dovetails with UT Southwestern priorities through the Peter O'Donnell Jr. Brain Institute and the O'Donnell School of Public Health, creating opportunities for collaboration across disciplines and accelerating research into dementia, Alzheimer's disease, and other age-related conditions.

• Dr. Cohen holds the C. Vincent Prothro Distinguished Chair in Human Nutrition Research.
• Dr. de Lemos holds the Sweetheart Ball-Kern Wildenthal, M.D., Ph.D. Distinguished Chair in Cardiology.
• Dr. Hobbs holds the 1995 Dallas Heart Ball Chair in Cardiology Research.
• Dr. Shah holds the Dallas Heart Ball Chair in Cardiac Research.

The Harry S. Moss Heart Trust

Dallas philanthropist, oilman, and civic leader Harry S. Moss envisioned a world less burdened by heart disease. Decades ago, Mr. Moss underwent emergency bypass surgery. The experience left him both awestruck and grateful, marveling at the science that had mended his heart and the people who made it possible.

"I have determined," he wrote in his will, "that I could not pursue any course which potentially could be of greater service to the community than the prevention and cure of the diseases of the heart."

Since its first grant in 1973, the Moss Heart Trust has propelled UT Southwestern Medical Center to the forefront of global cardiovascular research and care. What began as a single generous gift has grown into a multidecade partnership.

With visionary support from the Trust, UT Southwestern launched the Harry S. Moss Heart Center. In addition, UTSW restructured its cardiology program into three groundbreaking research divisions and built a robust pipeline of innovation.

The Moss Heart Trust's latest gift to support the Dallas Hearts and Minds Study displays the Trust's unwavering commitment to discovery. The Trust's ongoing support has played an important role in lessening the burden of heart disease in America.

"The lives of millions of people have been improved, extended, and saved because of work supported by the generosity of the Moss Heart Trust," said Daniel K. Podolsky, M.D., President of UT Southwestern. "Its investment in UT Southwestern has paid unparalleled dividends for patients around the world through breakthrough discoveries in the prevention, treatment, and ultimate cure of heart disease."

A new generation of physicians and scientists has been trained and mentored at UT Southwestern, in no small part because of the Trust's transformative influence. Harry S. Moss' vision was always about people - and his legacy lives in every heart that beats stronger because of the breakthroughs his support made possible.

• Dr. Podolsky holds the Philip O'Bryan Montgomery, Jr., M.D. Distinguished Presidential Chair in Academic Administration and the Charles Cameron Sprague Distinguished Chair in Biomedical Science.