Cancer is on track to replace heart disease as the leading cause of death in the United States within two years, according to a new study from researchers at Stanford University.
The researchers say the rate at which people are dying from heart disease is dropping more quickly than the rate at which people are dying from cancer. Why? According to the Centers for Disease Control and Prevention (CDC), this shift may be due to the ever-improving treatment of cardiovascular disease risk factors.
In the Stanford study, researchers looked at population and mortality rates over the past 100 years – and for most of the last century, heart disease was the leading cause of death all throughout the United States. Cancer was typically in second place. In 1993, cancer overtook heart disease as the leading cause of death in one state – Alaska. By 2002, it was two states, by 2005 it was 8, and by 2010 it was 23. If these rates continue, cancer will be the leading cause of death in the country by 2020, according to the CDC.
The Stanford researchers believe that the shift could also be partially attributed to economic and social conditions – including income, race, and access to care. In the early 20th century, infectious diseases like tuberculosis and the flu were the leading causes of death in the U.S. By the end of the century, chronic illnesses (cancer and heart disease) became the top killers. Research suggests that a similar shift is happening in the U.S. now. Stanford researchers looked at 32 million death records across 3,143 U.S. counties from 2003 to 2015 – and included demographic data, income, and race in their study.
They found that in 79% of the counties they looked at, heart disease was the leading cause of death in 2003. By 2015, that number was down to 59%. There are also disparities in different counties based on socioeconomic status, for both heart disease and cancer. The overall rate of people dying from heart disease decreased by 28% – with high-income counties experiencing a 30% drop, while low-income counties experienced a 22% drop. The cancer mortality rate decreased 16% overall – with high-income counties experiencing a 18% drop, compared to 11% for low-income counties.
There were also disparities among different ethnic groups. Researchers found that for white, Hispanic and Asian-American people, cancer replaced heart disease as the leading cause of death. The same pattern was not seen among African-Americans, American Indians, or Alaska natives. And yet, the rates at which different ethnicities die from cancer doesn’t align with these numbers. Take breast cancer for example, black women are 40% more likely to die from the disease than white women – despite the fact that black and white women are diagnosed with breast cancer at the same rates.
Breast Cancer Rates
Black and white women are diagnosed with breast cancer at about the same rate
Susan G. Komen Breast Cancer Foundation
The reason for the disparity could be due to lack of screening knowledge, income, or access to care. In an editorial published with the Stanford study, Swiss researchers Silvia Stringhini and Dr. Idris Guessous noted that how much genetic testing, screening, and personalized medicine actually affect cancer rates is still unclear … though all these preventative methods, combined with new and expensive cancer treatments may be contributing to the “increasing social inequalities in cancer survival.”
Smoking, obesity and diabetes trends may also be contributing to the disparities, the researchers noted. Between 1960 and 2015, the rate at which college-educated Americans smoked cigarettes decreased from 39% to 6%. Americans who didn’t graduate high school smoke at much higher rates (the 1960-2015 decrease went from 46% to 23%).
So what does this shift mean for Americans? “Undergo all of the recommended cancer screenings,” lead study author Dr. Latha Palaniappan said. And implement “lifestyle prevention practices, such as healthy diet and exercise, which are beneficial in lowering both cancer and heart disease mortality.”
Dr. Palaniappan said that awareness in low-income areas is key to getting both heart disease and cancer rates down across the entire U.S. “We need to work harder in lower income areas of the U.S. so they can see the same improvements in mortality. We need to focus more on heart disease and cancer prevention and treatment effort in African-American populations particularly.”