public health

Most of us want to stay on this planet as long as possible. While there are still differences depending on sex and region, we are now living longer as a species—and it seems life spans will only continue to grow longer.

Researcher David Atance of Universidad de Alcalá, Spain, and his team gathered data on the trends of the past. They then used their findings to project what we can expect to see in the future. Some groups have had it harder than others because of factors such as war, poverty, natural disasters, or disease, but the researchers found that morality and longevity trends are becoming more similar regardless of disparities between sexes and locations.

“The male-female gap is decreasing among the [clusters],” they said in a study recently published in PLOS One.

Remembering the past

The research team used specific mortality indicators—such as life expectancy at birth and most common age at death–to identify five global clusters that reflect the average life expectancy in different parts of the world. The countries in these clusters changed slightly from 1990 to 2010 and are projected to change further by 2030 (though 2030 projections are obviously tentative). Data for both males and females was considered when deciding which countries belonged in which cluster during each period. Sometimes, one sex thrived while the other struggled within a cluster—or even within the same country.

Clusters that included mostly wealthier countries had the best chance at longevity in 1990 and 2010. Low-income countries predictably had the worst mortality rate. In 1990, these countries, many of which are in Africa, suffered from war, political upheaval, and the lethal spread of HIV/AIDS. Rwanda endured a bloody civil war during this period. Around the same time, Uganda had tensions with Rwanda, as well as Sudan and Zaire. In the Middle East, the Gulf War and its aftermath inevitably affected 1990 male and female populations.

Along with a weak health care system, the factors that gave most African countries a high mortality rate were still just as problematic in 2010. In all clusters, male life spans tended to differ slightly less between countries than female life spans. However, in some regions, there were differences between how long males lived compared to females. Mortality significantly increased in 1990 male populations from former Soviet countries after the dissolution of the Soviet Union, and this trend continued in 2010. Deaths in those countries were attributed to violence, accidents, cardiovascular disease, alcohol, an inadequate healthcare system, poverty, and psychosocial stress.

Glimpsing the future

2030 predictions must be taken with caution. Though past trends can be good indicators of what is to come, trends do not always continue. While things may change between now and 2030 (and those changes could be drastic), these estimates project what would happen if past and current trends continue into the relatively near future.

Some countries might be worse off in 2030. The lowest-income, highest-mortality cluster will include several African countries that have been hit hard with wars as well as political and socioeconomic challenges. The second low-income, high-mortality cluster, also with mostly African countries, will now add some Eastern European and Asian countries that suffer from political and socioeconomic issues most have recently been involved in conflicts and wars or still are, such as Ukraine.

The highest-income, lowest-mortality cluster will gain some countries. These include Chile, which has made strides in development that are helping people live longer.

Former Soviet countries will probably continue to face the same issues they did in 1990 and 2010. They fall into one of the middle-income, mid-longevity clusters and will most likely be joined by some Latin American countries that were once in a higher bracket but presently face high levels of homicide, suicide, and accidents among middle-aged males. Meanwhile, there are some other countries in Latin America that the research team foresees as moving toward a higher income and lower mortality rate.

Appearances can be deceiving

The study places the US in the first or second high-income, low-mortality bracket, depending on the timeline. This could make it look like it is doing well on a global scale. While the study doesn’t look at the US specifically, there are certain local issues that say otherwise.

A 2022 study by the Centers for Disease Control and Prevention suggests that pregnancy and maternal care in the US is abysmal, with a surprisingly high (and still worsening) maternal death rate of about 33 deaths per 100,000 live births. This is more than double what it was two decades ago. In states like Texas, which banned abortion after the overturn of Roe v. Wade, infant deaths have also spiked. The US also has the most expensive health care system among high-income countries, which was only worsened by the pandemic.

The CDC also reports that life expectancy in the US keeps plummeting. Cancer, heart disease, stroke, drug overdose, and accidents are the culprits, especially in middle-aged Americans. There has also been an increase in gun violence and suicides. Guns have become the No. 1 killer of children and teens, which used to be car accidents.

Whether the US will stay in that top longevity bracket is also unsure, especially if maternal death rates keep rising and there aren’t significant improvements made to the health care system. There and elsewhere, there’s no way of telling what will actually happen between now and 2030, but Atance and his team want to revisit their study then and compare their estimates to actual data. The team is also planning to further analyze the factors that contribute to longevity and mortality, as well as conduct surveys that could support their predictions. We will hopefully live to see the results.

PLOS One, 2024. DOI:  10.1371/journal.pone.0295842