Nairobi, July 8 -- The countries that will lead the 21st century will not simply be those whose people live longer. They will be those whose people stay healthier for longer - able to learn, work, innovate, care for their families and participate fully in society. That is why the next frontier of development is not lifespan alone, but healthspan: the number of years people live in good health.

This is no longer a niche public health idea. It is fast becoming a global economic imperative. The World Health Organisation has shown that scaling up primary healthcare interventions in low- and middle-income countries could save 60 million lives and increase average life expectancy by 3.7 years by 2030, while most projected health gains under th...