People Are Living Longer, but Life Expectancy Remains Complicated

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A new study highlights fewer HIV/AIDS deaths in Africa, more deaths from war, and a strong, if imperfect, link between socioeconomic development and lifespan.

By Nathan Collins


(Photo: Artis Rams/Flickr)

In 1980, the average person on Earth lived to be 61.7 years old. In 2015, that number was 71.8 years. Though impressive, that increase belies complicated changes related to HIV and AIDS, war, standards of living, and more, according to a report published this week.

“At the global scale, age-specific mortality has steadily improved over the past 35 years,” and in many countries those improvements have come faster than would be expected on the basis of socioeconomic development, a team from the Global Burden of Disease study writes in the Lancet. Despite that, the team writes, life expectancy has dropped in some countries, and a few causes of death — notably war and interpersonal violence — are on the rise in the Middle East and elsewhere.

For the latest GBD study, more than 1,800 researchers from around the world gathered death certificates, household surveys, and more to create a database on lifespans and causes of death. Although there are important limitations — sometimes-unreliable death certificates and the possibility that some of the source data isn’t representative of their countries’ populations — the database is perhaps the most complete ever built.

In Syria, male life expectancy dropped from 73.9 years to 62.6 between 2005 and 2015.

Despite such challenges, the team was able to estimate life expectancies for 195 countries as well as how age distributions and causes of death have changed over time. Among the most reassuring findings, the analysis found that a number of countries in sub-Saharan Africa are “rebounding from an era of exceedingly high loss of life from HIV/AIDS.” Overall, deaths due to communicable disease (including HIV), maternal and neonatal illnesses, and poor nutrition declined substantially, especially in the decade between 2005 and 2015.

“At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence,” the team writes. In Syria, for example, male life expectancy dropped from 73.9 years to 62.6 between 2005 and 2015.

In general, as a nation’s sociodemographic index (SDI, a mix of per capita income, education, and birth rates) increased, so too did its life expectancy. This comes with important caveats: In much of Asia, South America, north Africa, and the Middle East, life expectancies exceeded what the researchers predicted based on SDI alone. Somewhat the opposite was true in Central and Eastern Europe, Central Asia, and in high-income countries more broadly. Despite rising AIDS deaths in sub-Saharan Africa throughout the 1990s, sub-Saharan Africa is now back to where it would be expected to be based on SDI.

Still, even as socioeconomic development marches on and efforts to tackle communicable diseases like HIV and malaria pick up steam, non-communicable diseases — most cancers, heart disease, and dementia, for example — may become a bigger problem. “Despite progress … population growth and aging mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems,” the researchers write.