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Cardiovascular health has improved dramatically across the U.S. over the past several decades, but those gains were enjoyed almost exclusively by the wealthiest segments of the population, a new analysis finds.

The progress made against cardiovascular disease masked broad, income-driven inequities in cardiovascular health that emerged and have grown increasingly wider since the late 1980s, according to the , published Wednesday in the ľ¹ÏÖ±²¥ journal Circulation: Cardiovascular Quality and Outcomes.

"The large reduction in cardiovascular risk – one of the main accomplishments of clinical and public health in the U.S. over the past half-century – was a benefit that was not equally shared," said lead study author Dr. Adam Richards, an associate professor of global health and medicine at George Washington University Milken School of Public Health in Washington, D.C. "People who earn less income did not benefit much, whereas all the benefit was concentrated among people with higher incomes."

According to , improvements in treatment and reductions in cardiovascular risk factors led to a 56% decline in heart disease death rates during the second half of the 20th century. The stroke death rate fell 70%.

But a growing body of research reveals gains made during that time and since have not been equitably distributed. Richards said he and his colleagues wanted to explore how widespread those inequities might be by analyzing health and income data more thoroughly across a wider age group and over a longer period of time than previous studies.

Their analysis looked at data for 26,633 U.S. adults assessed by the CDC's National Health and Nutrition Examination Survey from 1988 to 1994 and from 1999 to 2018. Participants were 40 to 75 years old and had no history of cardiovascular disease at the time of enrollment. They participated in household surveys as well as a physical examination to collect data, including income status and cardiovascular disease risk factors. Incomes ranged from at or below the poverty level to five times above that. (Updated annually, the federal poverty level for 2024 is $31,200 for a family of four.)

Overall, the population's predicted risk of having a heart attack or stroke within 10 years dropped dramatically over the 30-year study period. But those gains only applied to people in the top two income groups.

The 10-year cardiovascular risk fell from 7.7% to 5.1% for the wealthiest segment of the population and from 7.6% to 6.1% for the second-wealthiest group. But for people with the lowest incomes, risk increased from 8.1% to 8.7%, though the increase did not reach statistical significance.

The gains for people at the top of the income ladder widened the gap in cardiovascular disease risk between the two groups, which was almost nonexistent at the beginning of the study in the late 1980s, Richards said. By the end of the study, people at or below the poverty line faced a 70% higher risk of having a heart attack or stroke than their peers with an income five times higher, broadening the gap more than eightfold.

The findings suggest cardiovascular mortality among people with lower incomes also could be "contributing to the well-documented flattening of trends toward increased life expectancy, driven largely by slowed or reversal of progress among lower socioeconomic groups," Richards said.

"The conversation around this has focused on deaths of despair, such as accidents and overdoses," he said. "But if you focus on the fact that poor people are being left behind, our study suggests cardiovascular disease should also probably be part of that conversation."

The findings point to another gap – the lack of routine analysis of how new policies, treatments and interventions may be affecting different subgroups, said Dr. Debra Dixon, a cardiologist at Vanderbilt University Medical Center in Nashville, Tennessee. She was not involved in the new research.

For example, studies have shown unequal access to important cardiovascular interventions, such as procedures that treat faulty heart valves, for Black and Hispanic patients and people with lower incomes.

"Innovations in treatment are helpful, but if not accompanied by a way to create access for all, they worsen inequities," Dixon said.

Inequities are often the result of structural racism and other social drivers of health, according to an co-authored by Dixon and published concurrently with the study. For example, the historical and racially discriminatory lending practice known as "redlining" set the stage for poor housing conditions that, combined with a lack of access to health care services in underserved neighborhoods, helped perpetuate and exacerbate health disparities. These underlying conditions must be addressed if those gaps are to narrow, she said.

But that will require a shift in values, Dixon said. "We need policies that support the opportunity for everyone to live a healthy life."