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Cancer to surpass heart disease as leading cause of death in US by 2020

In the United States, the leading cause of death is projected to transition from heart disease to cancer among high-income individuals by 2020, according to research published in Annals of Internal Medicine.

“Recent data suggest that the United States is in the midst of an epidemiologic transition in the leading cause of death,” Katherine G. Hastings, MPH, research manager in the department of orthopedic surgery at Stanford University School of Medicine, and colleagues wrote.

“How this epidemiologic transition from heart disease to cancer is occurring in regions of the United States with different levels of economic development, and by racial/ethnic group, is unclear,” they wrote.

Hastings and colleagues sought to determine how the transition from heart disease to cancer as the leading cause of death in the country differs by county-level and sociodemographic characteristics.

The researchers examined U.S. death records (n = 32,510,810) from the National Center for Health Statistics Multiple Cause of Death mortality files from 2003 to 2015 of decedents aged 25 years or older for all-cause, heart disease and cancer mortality. They calculated the age- and sex-adjusted mortality rates and average annual percentage of change and stratified the data by county median household income. Counties in the lowest-income quintile had a mean income of $31,959 and those in the highest-income quintile had a mean income of $63,360.

In 2003, 79% of counties indicated heart disease was the leading cause of death, while cancer was the leading cause of death in the rest of the counties. In 2015, 59% of counties indicated heart disease was the leading cause of death, while cancer was the leading cause of death in the rest of the counties. The highest-income counties showed the most prominent shift to cancer as the leading cause of death.

From 2003 to 2015, the rates of mortality due to heart disease declined by 28% overall, ranging from 22% in low-income counties to 30% in high-income counties. During the same time frame, the rates of mortality due to cancer declined by 16% overall, ranging from 11% in low-income counties to 18% in high-income counties.

Among all racial/ethnic groups in the lowest-income counties, the leading cause of death remained as heart disease. Additionally, improvements in mortality for heart disease and cancer were smaller in the lowest-income counties.

“Our findings confirm a shift in the leading cause of death over time and show that poorer counties continue to have a higher burden of heart disease mortality,” Hastings and colleagues concluded. “In addition, data suggest a transition to cancer as the leading cause of death in high-income counties. Failure to account for differences in mortality by socioeconomic status and race/ethnicity in national reports may further marginalize populations already at increased risk for certain diseases or death.”

“Our findings may help inform improved policies, research, and clinical agendas as the United States moves through the epidemiologic transition in chronic disease–related mortality — from heart disease to cancer — in the coming decades,” they added.

In an accompanying editorial, Silvia Stringhini, PhD, and Idris Guessous, MD, PhD, both from Geneva University Hospitals, Switzerland, wrote that the findings by Hastings and colleagues offer another way of unravelling how population dynamics relate to the epidemiologic transition.

“Population aging and larger decreases in age-specific mortality from cardiovascular and respiratory diseases among elderly persons, especially those who are better off socioeconomically, are important elements in the shift from heart disease to cancer as the leading cause of death,” they wrote. “However, the effects of genetic testing, screening, and personalized treatment on cancer incidence and survival are unclear.”

If the new and expensive cancer therapies prove to be effective, they may contribute to the social inequalities in cancer survival, according to Stringhini and Guessous.

“Further research examining the socioeconomic and demographic correlates of these new facets of the epidemiologic transition will help to refine mortality projections in the United States and around the globe,” they wrote. – by Alaina Tedesco

Disclosure: The authors report no relevant financial disclosures.