As a result of increased prevention and improved medical treatment of cardiovascular disease (CVD), and despite increasing rates of obesity and diabetes, cancer has gradually surpassed CVD as the leading cause of death in high-income counties. However, CVD is more likely to be the leading cause of death in low-income counties.
While mortality from both cancer and cardiovascular disease (CVD) has steadily decreased in recent decades, CVD mortality has decreased more rapidly, resulting in cancer surpassing CVD as the leading cause of death in high-income counties in the United States, according to a new study. However, CVD is more likely to be the leading cause of death in low-income counties.
These findings mirror state-level data, which has shown that CVD was consistently the leading cause of death in the United States from 1950 to 2014, but starting in 2000, cancer mortality surpassed heart disease mortality in 2 states: Alaska and Minnesota. By 2014, cancer became the leading cause of death in 22 states.
“Heart disease has been the primary cause of death since the shift toward chronic disease as the leading cause of death in the United States in the early 1900s,” wrote the study researchers. But mortality rates have decreased, which “has been largely attributed to decreased smoking, improved awareness of diet and physical inactivity as risk factors, and better treatment of cardiovascular risk factors and acute coronary syndromes.”
As this shift continues, despite increasing rates of obesity and diabetes, researchers have estimated that cancer is expected to surpass CVD as the leading cause of death nationwide by 2020. Seeking to understand how this transition is occurring in regions with different levels of economic development, researchers examined US death records from the National Center for Health Statistics Multiple Case of Death mortality files from 2003 to 2015.
The researchers identified a total of 32,510,810 deaths across 3143 counties. During the study period, the age- and sex-adjusted mortality rate decreased by 12% in the total population, 7% in the lowest-income counties, and 15% in the highest-income counties.
Mortality rates for heart disease decreased by 28% (30% in high-income counties vs 22% in low-income counties), and cancer mortality rates decreased by 16% (18% in high-income counties vs 11% in low-income counties). CVD was the leading cause of death in 79% of all counties in 2003 compared with 59% in 2015, and cancer was the leading cause of death in 21% of counties in 2003 compared with 41% in 2015.
The transition to cancer as the leading cause of mortality in the United States occurred earlier in high-income countries than in low-income counties and earlier for Asian Americans, Hispanics, and non-Hispanic whites than for blacks and American Indians/Alaska Natives.
Expanding on these disparities, the researchers wrote: “Our data indicate continued disparities in cardiovascular and cancer mortality between blacks and other racial/ethnic groups, even in the highest-income quintiles. Blacks had higher overall mortality than any other group.”
But, the findings also suggest greater improvements for blacks than all other racial/ethnic groups for all-cause, CVD, and cancer mortality during the study period.
Hastings K, Boothroyd D, Kapphahn K, et al. Socioeconomic differences in epidemiologic transition from heart disease to cancer as the leading cause of death in the United States, 2003 to 2015: An observational study [published online November 13, 2018]. Ann Intern Med. doi: 10.7326/M17-0796.