The global burden of disease is shifting, found a new study by the University of Denver, from infectious diseases to chronic ones such as cancer, diabetes and heart disease.
"Because of great advances, the number of deaths globally from communicable diseases has fallen significantly compared to deaths from chronic diseases, which primarily affect the elderly," said report writer, Barry Hughes.
Figures show the global death risk from chronic, or long-term disease is 50 per cent higher than from infectious or communicable diseases. However, infectious diseases still have a higher percentage of potential loss of years of life, because they kill more babies and children.
But by 2020, chronic diseases will take even more years of life than communicable ones. The rapidly ageing population is driving the switch, researchers say.
"We're bringing the communicable diseases under control - malaria for example - with interventions such as more bed netting to protect from mosquitoes; Aids death rates are also on a downward trend," said Mr Hughes.
But some parts of Africa, particularly in the north and south are seeing higher levels of obesity rates and a rising number of obesity-linked diseases such as diabetes, he noted, blaming rising incomes.
He also predicts that diseases brought on by air pollution and global warming will rise.
Altogether, people's life expectancies are getting longer around the world, too. "We're doing many significant things right," Mr Hughes said. "We've been good, for example, at attacking specific diseases such as smallpox and polio. On a global basis we've seen some great success."
But there are barriers to better health care such as money and the knowledge and technology to find vaccines for malaria and Aids, he said.
Worldwide, there are more than 33 million people living with HIV/Aids, according to the World Health Organisation and most of them are in sub-Saharan Africa. In 2007, 2.5 million children under 15 were living with HIV/Aids with 1,150 getting infected every day.
Every year, malaria kills nearly two million people and infects between 400–500 million. Again, most of these deaths are in sub-Saharan Africa. And diarrhoea kills 2.2 million people a year, mostly children under five according to The Rehydration Project. These deaths account for about 15 per cent of all deaths of under-fives in the world's poorest countries.