Cancer overtakes heart disease as biggest killer in wealthy countries

Cancer has overtaken heartdisease as the leading cause of death in wealthy countries and could become the world's biggest killer within just a few decades if current trends persist, researchers said on Tuesday.

Publishing the findings of two large studies in The Lancetmedical journal, scientists said they showed evidence of a new global "epidemiologic transition" between different types of chronic disease.

While cardiovascular disease remains, for now, the leadingcause of mortality worldwide among middle-aged adults accounting for 40 per centof all deaths that is no longer the case in high-income countries, where cancer now kills twice as many people as heart disease, the findings showed.

"Our report found cancer to be the second most common causeof death globally in 2017, accounting for 26 per centof all deaths. But as [heart disease]rates continue to fall, cancer could likely become the leading cause of death worldwide, within just a few decades," said Gilles Dagenais, a professor at Quebec's Laval University in Canada who co-led the work.

Of an estimated 55 million deaths in the world in 2017, theresearchers said, around 17.7 million were due to cardiovascular disease a group of conditions that includes heart failure, angina, heart attack and stroke.

Around 70 per centof all cardiovascular cases and deaths are due to modifiable risks such as high blood pressure, high cholesterol, diet, smoking and other lifestyle factors.

In high-income countries, common treatment withcholesterol-lowering statins and blood-pressure medicines have helped bring rates of heart disease down dramatically in the past few decades.

Dagenais's team said their findings suggest that the higherrates of heart-disease deaths in low-income countries may be mainly due to a lower quality of healthcare.

The research found first hospitalization rates and heartdisease medication use were both substantially lower in poorer and middle-income countries than in wealthy ones.

Improve education for impact

The research was part of the Prospective Urban and RuralEpidemiologic (PURE) study, published in The Lancet andpresented at the ESC Congress in Paris.

Countries analyzed included Argentina, Bangladesh, Brazil,Canada, Chile, China, Colombia, India, Iran, Malaysia, Pakistan, Palestine, Philippines, Poland, Saudi Arabia, South Africa, Sweden, Tanzania, Turkey, United Arab Emirates and Zimbabwe.

Despite including as many as 21 countries, the researchers said to exercise caution in generalizing the results to all countries, particularly since they lacked data from west Africa, north Africa or Australia with few participants from the Middle East.

The effect of risk factors such as poor diet andhousehold air pollutionvariedby the economic level of the countries, the journal's editors said. Global health policies should be adapted to different groups of countries based on factors such as the expected benefit and access to health care.

Stephanie Read of Women's College Research Institute in Torontoand Sarah Wild of the University of Edinburgh, U.K., wrote a journal commentary published with the research.

"[T]heirfindings can inform the effective use of limited resources for example, by indicating the importance of improving education across the world and improving diet and reducing household air pollution in less developed countries. The value of collecting similar data to inform policy in a wider range of countries is clear, while improving lifestyle choices and modifying their social and commercial determinants remain a challenge," Read and Wild wrote.

They said the findings suggest that improving education in low-income countries and middle-income countries might be expected to have a larger effect on mortality than reducing prevalence of diabetes, abdominal obesity, depression, or low physical activity.

Jeremy Pearson, associate medical director at the British Heart Foundation, said heart and circulatory diseases remain the leading cause of death and disability worldwide.

As the population grows and ages, more people canexpect to survive heart attacks and strokes, andthe number of people living with the debilitating after-effects of thetwo conditions will continue to rise, Pearson said in an email calling for research into the prevention, treatment and cures for all heart and circulatory diseases.