Progress in reducing the number of deaths related to cardiovascular disease has been waning in recent years, heightening concerns that the obesity epidemic in the United States is undoing improvements in heart health.

A research letter published Tuesday in Journal of the American Medical Association confirms that although the death rates from heart disease, diabetes, stroke and related disorders have been decreasing for decades, the rates have recently slowed or stalled.

“At best, progress has slowed to a halt, and, at worst, our rates of cardiovascular disease are going up,” said Steven Nissen, chief academic officer for the Heart and Vascular Institute at Cleveland Clinic. “And the cause, pretty much everybody agrees, is the obesity epidemic and all of its downstream consequences.”

More than 93 million adults and nearly 14 million children and adolescents in the United States are considered to be obese – a number that has been climbing for decades, according to the Centers for Disease Control and Prevention. Obesity, which disproportionately affects black and Hispanic people, can lead to diabetes, stroke and heart disease, the latter being the leading cause of death in the United States.

Researchers analyzed death records from 1999 to 2017 from the CDC and found a measurable shift in the past decade. The decline in mortality rates from heart disease has slowed, the decline in mortality rates from stroke and diabetes has plateaued, and there has been an increase in mortality from hypertension-related problems, such as kidney disease.

Senior author Sadiya Khan, assistant professor of cardiology and epidemiology at Northwestern University’s Feinberg School of Medicine, said the research also showed that the disparities between black and white Americans have persisted, with black Americans at a greater risk of death from these diseases. The CDC released data last year showing that the death rate for heart disease has been decreasing about 2.4 percent per year among white people and 2.2 percent per year among black people over the past 50 years.

Khan said the researchers were surprised to learn that “we’re not seeing continued progress” despite a steady decline in smoking – a common cause of cardiovascular disease – and ongoing advances in medicine, including diagnostics, new drugs to treat high cholesterol, high blood pressure and diabetes and surgical techniques.

“The concern is that if there’s a plateau now, what’s coming in the next five to 10 years?” she said.

Cardiologist Salim Virani, chair of the American College of Cardiology’s Council for the Prevention of Cardiovascular Disease, said, “It’s not all negative – death rates have come down.” But he said it’s important to continue pushing for medical advancements – uniformly, across all populations – to further reduce death rates.

“As those rates of decline are slowing down, we need to continue to evolve our thinking, as well as our therapies, to make sure that we catch up with those stalling rates in decline,” Virani said. “It basically is a question that is posed, and we need to come up with answers both in terms of what’s driving it and what can be done to address it.”

Health experts agree a key component is early intervention in schools, encouraging exercise and healthy eating habits among children, and discouraging risky behaviors such as smoking that may lead to problems later on. Nissen, with the Cleveland Clinic, said that particularly with obesity, “we have got to attack this problem before it gets to the point where people are really obese and are in trouble. Because once people have developed severe obesity, reversing that is very difficult.”

Eduardo Sanchez, the American Heart Association’s chief medical officer for prevention and chief of the Center for Health Metrics and Evaluation, said in a statement about the new study: “While we are heartened by the collective impact of efforts to reduce cardiometabolic mortality, we cannot and will not be complacent about recent reductions and plateauing in the rates at which CVD [cardiovascular disease] mortality is dropping.” He called for a continued focus on reducing smoking, increasing physical activity and healthy diets, and managing health problems such as high blood pressure, high cholesterol, diabetes and obesity, as well as eliminating the disparities in mortality rates among all populations.