The importance of a healthy diet and lifestyle has long been acknowledged by healthcare professionals as one of the keys to a long and happy life. And for the people of Spain, the evidence bears this out as they’re about to topple the Japanese from the top spot in the longest life expectancy charts.

By 2040, Spaniards can expect to live to an average age of 85.8 years. That’s noticeably up from the 2016 level of 82.9 years when Spain was ranked fourth out of 195 countries. Japan now sits at number two in the Institute for Health Metrics and Evaluation (IHME) ranking with an average life expectancy of 85.7, only slightly behind that of Spain. It was 83.7 years in 2016.

The chief explanation for Spain’s pronounced improvement is the country’s Mediterranean diet which helps guard against some of the five biggest early killers of the modern era: obesity, high blood pressure, elevated levels of blood sugar, tobacco use and excessive alcohol consumption.

In 2016, four of the 10 most common causes of early death were non-communicable diseases (NCDs). But by 2040 NCDs are forecast to account for seven: ischemic heart disease, stroke, chronic obstructive pulmonary disease (COPD), chronic kidney disease, Alzheimer’s disease, diabetes, and lung cancer.

“The future of the world’s health is not preordained,” says the study’s lead author Dr Kyle Foreman, Director of Data Science at the IHME.

“But whether we see significant progress or stagnation depends on how well or poorly health systems address key health drivers,” he adds, referring to the five major influences on premature mortality.

The IHME researchers examined different independent drivers of health, including sociodemographic measurements of fertility, per capita income and years of education, along with more obvious factors like smoking, high body mass index, and access to clean water and sanitation.

In addition to calling attention to the growing importance of NCDs, the analysis exposes a substantial risk of HIV/AIDS mortality rebounding, which could undo recent life expectancy gains in several nations including – but not limited to – those in sub-Saharan Africa.

Chinese health officials recently announced there has been a 14% increase in HIV infection rates in China, with around 40,000 new cases reported in the second quarter of 2018 alone.

Spain leads the way in the 2040 Life Expectancy rankings from the IHME.

Image: IHME

Citizens of all the top 10 countries are predicted to live into their mid 80s. Yet there are startling differences and inequalities revealed by the IHME study, which looked at best- and worst-case scenario predictions. In one worst-case scenario, life expectancy drops by almost half for all countries over the next generation. By contrast, in the better scenario, 158 countries will see life expectancy gains of at least five years, while 46 nations may see gains of 10 years or more.

Syria has seen the greatest rise up the global rankings – from 137th in 2016 to 80th by 2040. But this change is because of a predicted levelling off of armed conflict.

Among the bottom-ranked nations, including Lesotho, Swaziland, Central African Republic, and South Africa, the better and worse scenarios in 2040 range from a high of 75.3 years in South Africa to a low of 45.3 years in Lesotho – a predicted potential difference of 30 years.

But the predictions for some of the world’s most affluent nations are among some of the most surprising. The USA is the IHME index’s biggest loser among high-income countries falling from 43rd in 2016 to 64th in 2040, due to an increase of just 1.1 year – from 78.7 to 78.9 years.

Dr Christopher Murray, IHME Director, explains the purpose of worse and best scenario ranges. “These scenarios offer new insights and help to frame health planning, especially regarding long lag periods between initial investments and their impacts, such as in the research and development of drugs.”