- Includes rankings of life expectancy for 35 countries across Asia, North and Latin America, Australasia and Europe - tables available
- Out of 35 developed nations, South Korea is likely to see the largest increase in life expectancy, with female life expectancy potentially surpassing 90 years
- In 2030, UK life expectancy is estimated to reach 85.3 for women and 82.5 for men; and 83.3 for women and 79.5 for men in the USA
Life expectancies in developed countries are projected to continue increasing, with women's life expectancy potentially surpassing 90 years old in South Korea by 2030, according to a study published in The Lancet.
The study predicts life expectancy is likely to be highest in South Korea (90.8 years old), France (88.6 years old) and Japan (88.4 years old) for women, and in South Korea (84.1 years old), Australia (84.0 years old) and Switzerland (84.0 years old) for men.
The researchers advise that increasing life expectancies will have major implications for health and social services that will need to adapt and will require policies to support healthy ageing, increase investment in health and social care, and possibly changes to retirement age.
"As recently as the turn of the century, many researchers believed that life expectancy would never surpass 90 years," said lead author Professor Majid Ezzati, Imperial College London, UK. "Our predictions of increasing lifespans highlight our public health and healthcare successes. However, it is important that policies to support the growing older population are in place. In particular, we will need to both strengthen our health and social care systems and to establish alternative models of care such as technology-assisted home care." 
In the study, researchers used a statistical technique used in weather forecasting to determine their projections and how certain they are. They developed 21 models to predict life expectancy in 35 developed countries - unlike most life expectancy projections which are based on a single model - and combined the results from these models based on how well they performed. All the predictions in the study come with a range of uncertainty. For instance, there is a 90% probability that life expectancy for South Korean women in 2030 will be higher than 86.7 years, and a 57% probability that it will be higher than 90 years.
Although life expectancy is predicted to increase across all 35 countries, the extent of the increase varies by country. Comparing 2030 and 2010 life expectancies, female life expectancy is projected to increase most in South Korea, Slovenia and Portugal (6.6, 4.7 and 4.4 years, respectively). While for men life expectancy will increase most in Hungary, South Korea and Slovenia (7.5, 7.0 and 6.4 years).
Life expectancy is predicted to increase least in Macedonia, Bulgaria, Japan and the USA (1.4, 1.5, 1.8 and 2.1 years) for women, and in Macedonia, Greece and Sweden and the USA (2.4, 2.7, 3.0 and 3.0 years) for men.
The USA is predicted to see relatively small improvements in life expectancy (from 81.2 for in 2010 to 83.3 in 2030 for women and 76.5 to 79.5 for men). US life expectancy is already lower than most other high-income countries, and is expected to fall further behind in 2030, potentially as a result of its large inequalities, absence of universal health insurance and of the country having the highest homicide rate, body mass index (BMI) and death rates for children and mothers of all high-income countries.
Conversely, South Korea's projected gains may be the result of continued improvements in economic status which has improved nutrition for children, access to healthcare and medical technology across the whole population. This has resulted in fewer deaths from infections and better prevention and treatment for chronic diseases, in a way that is more equitable than some Western countries.
As well as calculating life expectancy at birth in 2030, the researchers projected how long those aged 65 years were likely to live in 2030. They found that women were likely to live an additional 24 years in 11 of the 35 countries, and that 65-year old men were likely to an additional 20 years in 22 countries  - illustrating that older populations are likely to continue growing across the developed world.
With an ageing population it will be important to help people to age healthily and ease the impact of an ageing population on health systems through programmes that support healthy lifestyles and detect and treat diseases early. Providing assistive technology could also help older people remain in their homes by compensating for loss of mobility and senses, while building communities that are more accessible and providing good transportation services could help older people access amenities while staying in their community for longer.
The social implications of this change will also likely require changes to pensions and retirement, with further payments of social security and pensions needed to support those living longer. As a result, the researchers propose changes to working practice through changing retirement age or creating schemes that allow a gradual transition to retirement.
"Dealing with an ageing population will require a combination of strengthening and positioning our health and social care systems and our societies as a whole, so as to ensure that people age healthily, continue to contribute to society for longer, and receive appropriate pension and care once they age." said Professor Ezzati. 
The researchers explain that the next step of their research will be to extend their model to specific diseases as well as to all countries to provide more accurate predictions of life expectancy globally. The study cannot take into account unprecedented events, such as major political change that affects social and health system determinants of health, in its forecasts because the effects of such events are unknown or highly uncertain.
Writing in a linked Comment, Dr Ailiana Santosa, Umeå University, Sweden, said: "Countries are moving towards universal health coverage. Forecasting life expectancy at birth and at age 65 years can help governments and health services to make the right investments in health, such as averting deaths due to infectious diseases and reducing maternal and child mortality. Achieving universal health coverage is worthy, plausible, and needs to be continued."
NOTES TO EDITORS
The study was funded by the UK Medical Research Council and the US Environmental Protection Agency. It was conducted by scientists from Imperial College London, the World Health Organisation, Northumbria University and the University of Washington.
 Quote direct from author and cannot be found in the text of the Article.
 The projected life expectancy for those aged over 65 in 2030 is higher than for those born in 2030 because the figure for those born in 2030 includes people who will die before the age of 65, which makes the life expectancy average lower.
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