Heart disease is the number one cause of death in the United States and has been since 1910 — with the exception of the influenza pandemic which took place between 1918 and 1920. The silver lining to these cold, hard facts is that since 1969, age-related death rates for heart disease fell significantly from 520.4 deaths per 100,00 Americans to 169.1 per 100,000 in 2013, according to the American Heart Association. However, new research published in JAMA Cardiology revealed that the rate of decline of cardiovascular death has slowed down since 2011.

Researchers led by  Dr. Stephen Sidney of Kaiser Permanente Northern California discovered this deceleration of the decline in cardiovascular mortality — from heart disease, as well as other conditions that involve narrowed or blocked vessels, such as high blood pressure — when they were examining recent national trends in death rates due to cardiovascular disease, heart disease, stroke and cancer from January 2000 to December 2011 and January 2011 to December 2014. They found that during the 21st century, heart disease mortality declined at a much greater rate than cancer, and for a quick second, it appeared that cancer would become the leading cause of death in the U.S.

There was also a decline in cardiovascular disease and stroke mortality. However, after 2011, the rate of decline for these cardiovascular conditions decelerated substantially, while cancer mortality remained stable. For example, between 2000 and 2011,  cardiovascular disease, heart disease and stroke saw a 3.79, 3.69 and 4.53 percent rate of decline. The rates of decline for 2011 to 2014 were 0.65, 0.76, and 0.37 percent. Meanwhile, the rate of decline for cancer mortality was 1.49 percent from 2000 to 2011, and 1.55 percent from 2011 to 2014.

Had the rates of decline for cardiovascular mortality from 2000 to 2011 persisted, it is possible that heart disease mortality may have been lower than cancer mortality, researchers said.

“A significant concern is the possibility that [cardiovascular disease] mortality rates stop decreasing and perhaps even increase, as suggested by provisional estimates though the third quarter of 2015 of higher mortality rates than in 2014 for [heart disease] and stroke,” researchers wrote. Their worries aren’t buffered by the increasing prevalence of obesity and diabetes at “epidemic proportions,” as they both have been linked to an increased risk of developing cardiovascular disease.

Researchers attribute the decline in heart disease mortality in the U.S. to the expanded use of evidence-based medical therapies as well as changes in risk factors and lifestyle modifications which may have been a result of the emphasis on cardiovascular health. However, they say more work is needed to improve cardiovascular outcomes and reduce mortality.

“Given the high absolute burden and associated costs of heart disease and stroke, continued vigilance and innovation are essential in our efforts to address the ongoing challenge of cardiovascular disease prevention,” researchers concluded. “However, the recent deceleration in the rate of decline in heart disease mortality is alarming and warrants expanded innovative efforts to improve population-level cardiovascular disease prevention.”

Source: Sidney S, Quesenberry, Jaffe M, et al. Recent Trends in Cardiovascular Mortality in the United States and Public Health Goals. JAMA Cardiology. 2016.