People around the world lived on average to a ripe old age of 71.5 in 2013, up from 65.3 in 1990, according to a new study.

The Global Burden of Disease Study 2013, published in The Lancet, a British health journal,  shows that global life expectancy rose by 5.8 years in men and 6.6 years in women between 1990 and 2013.

The increase was attributed to falling death rates from cancers (down by 15 per cent) and cardiovascular disease (down by 22 per cent) in high-income regions of the world – despite significant increase in liver cancer and chronic kidney deaths.

In less affluent regions, it was attributed to rapidly declining death rates due to  diarrhoea, lower respiratory tract infections and neonatal disorders.

Only Sub-Saharan Africa did not benefit from the upward trend with deaths from HIV/Aids resulting in a drop in average life expectancy by five years.

Lead author Dr Christopher Murray, professor of Global Health at the University of Washington, said the progress seen against a variety of illnesses and injuries is remarkable, but added that a lot more needed to be done.

"The collective action and funding given to the major infectious diseases such as diarrhoea, measles, tuberculosis, HIV/Aids and malaria has had a real impact,” he said.

The study found, however, that death rates from some major chronic conditions were on the rise, including liver cancer caused by Hepatitis C, drug use disorders, chronic kidney disease, diabetes and pancreatic cancer.

The Global Burden of Disease Study 2013, funded by Bill & Melinda Gates Foundation, found that some low-income countries such as Nepal, Rwanda, Ethiopia, Niger, the Maldives, Timor-Leste and Iran had seen exceptional gains over the past 23 years, with life expectancy rising by more than 12 years for both sexes.

Life expectancy of Rwandans has over the last decade increased to 64.5 for both sexes from 48.4 years for men and 53.8 years for women recorded in 2002, according to the report of Fourth Population and Housing Census conducted in 2012 by the National Institute of Statistics of Rwanda (NISR). The report was released in April this year.

And, despite significant drops in under-five deaths from 7.6 million in 1990 to 3.7 million in 2013, the study also indicated that lower respiratory tract infections, malaria, and diarrhoeal diseases were still in the top five global causes of child deaths, claiming almost two million children annually.