What drives improvements in life expectancy?

One of the most important inputs to health is healthcare. One common way of measuring national healthcare consumption and production is to estimate aggregate expenditure on healthcare. Health spending measures the final consumption of health care goods and services (i.e. current health expenditure) including personal health care and collective services, but excluding spending on investments. Health care is financed through a mix of financing arrangements including government spending and compulsory health insurance as well as voluntary health insurance and private funds such as households’ out-of-pocket payments.

This visualization shows the cross-country relationship between life expectancy at birth and healthcare expenditure per capita at two points in time, about a generation apart (2000 and 2017 respectively).

The arrows connect these two observations, thereby showing the change over time of both measures for all countries in the world.

As it can be seen, countries with higher expenditure on healthcare per person tend to have a higher life expectancy. Looking at the change over time, as countries spend more on health, life expectancy increases.
Data: Our World in Data

Health Expenditure in the countries with the highest life expectancy

American life expectancy is the lowest in the rich world, especially considering how much money is spent on health. As per researchers at Imperial College London and the World Health Organization, that is partly because America is the only country in the Organisation for Economic Co-operation and Development (OECD) that does not have universal health care, meaning poorer health for poorer people. It also has the highest maternal and child mortality rates, so fewer people reach old age. High obesity and homicide rates shorten lifespans as well.

Compared with other developed countries, expenditure on health (measured in USD per capita spent on health by private and public sectors), is highest in the United States more $10,000.00. Switzerland is the next highest in expenditures more $8,000.00. Including Switzerland, other developed countries spend much less on health and have a higher life expectancy than the United States.
Data: The Organisation for Economic Co-operation and Development (OECD)

Projections of life expectancy

Population forecasting is not simple. Demographers use mortality data—information about when people die and why—to estimate the likely life expectancy of people still alive. The UN, the World Health Organisation (WHO) and others produce periodic forecasts that are fairly similar. Wealthy countries such as Japan, Switzerland and Australia have the highest life expectancies, though the estimates vary slightly depending on the methodology used. However, the researchers at Imperial College London and the World Health Organisation,  whose studies were published in the Lancet, a medical journal, developed an ensemble of 21 forecasting models, all of which probabilistically contributed towards the final projections. They applied this approach to project age-specific mortality to 2030 in 35 industrialized countries with high-quality vital statistics data.They used age-specific death rates to calculate life expectancy at birth and at age 65 years, and probability of dying before age 70 years, with life table methods.

As per their funding life expectancy is projected to increase in all 35 industrialized countries with a probability of at least 65% for women and 85% for men. There is a 90% probability that life expectancy at birth among South Korean women in 2030 will be higher than 86.7 years, the same as the highest worldwide life expectancy in 2012, and a 57% probability that it will be higher than 90 years. Of the countries studied, the USA, Japan, Sweden, Greece, Macedonia, and Serbia have some of the lowest projected life expectancy gains for both men and women.