Michael C. Harding and Evan Thacker, Department of Health Sciences

INTRODUCTION:

In 1900 the three leading causes of death in the United States were pneumonia and influenza;
tuberculosis; and gastritis, enteritis, and colitis.¹ However, through a combination of improved sanitation, the discovery of antibiotics, and the advent of vaccination programs, deaths from
infectious diseases subsided and soon gave way to chronic diseases.² Shortly after the turn of the century, diseases of the heart became of the number one cause of death, and in the 1940s, cancer
began consistently appearing at number two. Since then, heart disease and cancer have remained
firmly entrenched as the number one and two causes of death, respectively.

Although the gap between heart disease and cancer mortality rates was initially substantial, in
recent decades, it has been narrowing. While “diseases of the heart” remains the leading cause of
death in the U.S. as a whole, the aggregate, national-level data can obscure what happens in
smaller groups. For example, Jemal and colleagues showed that since 1999, cancer has been the
leading cause of death for persons younger than 85.³ The purpose of the present study was to
determine if national-level data obscure state-specific transitions from heart disease to cancer as
the leading cause of death.

METHODS:

Using the CDC Wonder tool we obtained state-specific underlying cause of death data for all 50
states and the District of Columbia for each year from 1999 to 2014. Gathering state-specific
data allowed us to analyze the national data from the perspective of individual states, revealing
that the national transition from diseases of the heart to malignant neoplasm as the leading cause
of death is taking place at a greater rate in some states.

Our primary measurement was mortality rate for heart disease and cancer by state. A mortality
rate ratio (RR) was calculated by dividing the heart disease mortality rate by the cancer mortality
rate. Maps were then created using ArcMap Software version 13.1, and the projections and
scales were chosen to provide a relatively familiar presentation of the geographic features.

RESULTS:

In 1999 heart disease was the leading cause of death in 49 states (Figure 1). By 2014, 29 states
had experienced at least one year when cancer mortality exceeded heart disease mortality
(MRR2014 < 1.00). Of those, 20 states had experienced at least five years when cancer mortality predominated, and seven states had experienced at least 10 years when cancer mortality
predominated. While 17 states remained consistently cancer-predominant every year through
2014 after first experiencing cancer mortality predominance, 12 states fluctuated between cancer
mortality predominance and heart disease mortality predominance across years.

DISCUSSION:

In conclusion, our data support our hypothesis: national-level mortality data do obscure statespecific
transitions from heart disease to cancer as the leading cause of death. The oversimplified
message that heart disease is the leading cause of death masks successes in heart disease
prevention and control. The trends presented here are driven by the steep decline of heart disease
mortality rates and relatively modest decline of cancer rates. Earl Ford and colleagues showed
that about half of the dramatic reduction in heart disease mortality can be attributed to improved
treatments and about half to the reduction of risk factors.⁴ Our full-length publication includes more in-depth exploration of the research question, including analysis by age group, sex, and
race/ethnicity groups.

¹ Remington, P. L., Brownson, R. C., & Wegner, M. V. (2010). Chronic Disease Epidemiology and Control.
² Brownson, R. C., & Bright, F. S. (2004). Chronic disease control in public health practice: looking back and moving forward. Public health reports,119(3), 230.
³ Jemal, A., Murray, T., Ward, E., Samuels, A., Tiwari, R. C., Ghafoor, A., … & Thun, M. J. (2005). Cancer statistics, 2005. CA:a cancer journal for clinicians,55(1), 10-30.
⁴ Ford, E. S., Ajani, U. A., Croft, J. B., Critchley, J. A., Labarthe, D. R., Kottke, T. E., … & Capewell, S. (2007). Explaining the decrease in US deaths from coronary disease, 1980–2000. New England Journal of Medicine, 356(23), 2388-2398.