For middle-aged people in wealthy nations, cancer is now the number one killer. In fact, they are more than twice as likely to die of cancer than heart disease.
Cardiovascular disease (CVD), which includes heart attacks and strokes, has long been the top cause of death world-wide. But when researchers from Canada's McMaster University analyzed data collected from a global initiative that followed the fate of almost 200,000 people in 21 countries from 2005 to 2016, they found a surprise.
Instead of heart disease, cancer is now the number one killer in the richer nations studied, at least for the middle-aged.
A closer look at the findings, however, doesn’t necessarily mean cancer rates are soaring in places with higher incomes. It actually points to success in treating cardiovascular disease, at least in countries where people can afford and receive modern healthcare.
Cancer could soon be the #1 cause of death in the world
The research showing cancer is now the number one killer in wealthy countries, published in The Lancet, used data from the Prospective Urban Rural Epidemiology (PURE) study led by the Population Health Research Institute (of McMaster University and Hamilton Health Sciences in Hamilton, Canada).
The high-income countries studied were Canada, Saudi Arabia, Sweden, and the United Arab Emirates, while the middle-income countries were Argentina, Brazil, Chile, China, Columbia, Iran, Malaysia, Palestine, Philippines, Poland, Turkey, and South Africa. The lower-income countries included in the research were Bangladesh, India, Pakistan, Tanzania, and Zimbabwe.
Although the U.S. was not included in this study, Salim Yusuf, MD, the lead investigator and a professor of medicine at McMaster, explained the results are likely to be applicable to other countries with similar economic and social characteristics and healthcare, including the U.S.
"The fact that cancer deaths are now twice as frequent as CVD deaths in high-income countries indicates a transition in the predominant causes of death in middle age," Yusuf, MD, executive director of McMaster’s Population Health Research Institute (PHRI), explained.
"As CVD declines in many countries because of prevention and treatment, cancer mortality will likely become the leading cause of death globally in the future.”
Cardiovascular disease is still a top killer
Although, in high-income countries, cancer is now the number one cause of death in middle-aged people, cardiovascular disease, heart attacks, stroke, and other forms of CVD are still the top killers of adults in the same age group in most less wealthy areas of the world.
In the U.S., Centers for Disease Control and Prevention (CDC) statistics show heart disease remains the top cause of death for all age groups (while the McMaster research looked at deaths in the middle-aged only). What’s more, while cancer is the number two killer of Americans, it is only slightly behind heart disease in the toll it takes on lives in the U.S.
Overall, CVD is the most common cause of mortality globally, resulting in 40 percent of deaths. However, the McMaster team’s research showed heart disease in middle-age caused only 23 percent of deaths in the high-income countries, compared to 41 percent in middle income countries and 43 percent in the nations with the lowest income.
In comparison, cancer was the second most common cause of death world-wide — responsible for over half of deaths in wealthier nations, 20 percent in middle income countries, and only 15 percent in the low-income countries.
Although there are higher rates of CVD and deaths from heart disease in poorer countries, many cardiovascular disease risk factors, including obesity and type 2 diabetes, are lower. The researchers suggest the explanation lies in less available and effective medical care in poor areas, compared to wealthier nations.
New efforts to reduce cancer deaths are needed
The advances in preventing cardiovascular disease and the modern and effective care of people with CVD in wealthier nations clearly is saving lives. And that gives hope research and more preventive strategies will lower the death rate from malignancies eventually, too, worldwide.
"The implications are that in high income countries, while efforts to prevent and treat CVD should continue, new efforts to reduce cancer are required," said Darryl Leong, PhD, the co-lead author of the study and a PHRI scientist.
November 26, 2019