Heart disease is no longer the leading cause of death in rich countries – now it is cancer that could become the world’s biggest killer in just a few decades if current trends continue, scientists warn.

The scientists said they provided evidence of new global epidemiological transitions between different types of chronic diseases.

While cardiovascular disease remains the leading cause of mortality worldwide among people in middle age – and accounts for 40% of all deaths – this is no longer the case in high-income countries, where cancer now kills twice as many as heart disease, show the results of studies.

– Our work found that cancer was the second most common cause of death in the world in 2017 and that it accounted for 26 percent of all deaths. But as the rate of heart disease continues to decline, cancer could become the leading cause of death in the world in just a few decades – said Phil Dazene, a professor at Laval University in Quebec, Canada.

Of the approximately 55 million people who died in 2017 worldwide, about 17.7 million died of cardiovascular disease, scientists said. About 70 percent of those diseases are caused by high blood pressure, high cholesterol, poor nutrition and smoking – things that can affect you.

In high-income countries, treating high cholesterol and blood pressure with medications has helped reduce the rate of heart disease in recent decades.

Dazene’s team noted that their findings suggested that the reason for a higher death rate due to heart disease in poorer countries could be the poorer quality of health care.

Research shows that rates of first hospitalization and drug use for heart disease are much lower in poorer countries and in middle-income countries than in rich countries.

Among the countries analyzed are, Philippines, India, Iran, Canada, China, Colombia, Malaysia, Pakistan, Poland, Turkey, United Arab Emirates, Argentina, Bangladesh, Brazil, Chile, Saudi Arabia, Sweden, Tanzania.