Life expectancy for young people can be as much as 14 years shorter in violent countries compared to peaceful nations, according to a global study.
A team, led by researchers at the University of Oxford in the UK, shows a direct link between the uncertainty of living in a violent setting and a "double burden" of shorter and less predictable lives, even for those not directly involved in the violence.
The study, published in the journal Science Advances, estimates a gap of around 14 years in remaining life expectancy -- the number of years a person can expect to live -- at age 10 between the least and most violent countries.
In El Salvador, Honduras, Guatemala and Colombia, the gap in life expectancy with high income countries is predominantly explained by excess mortality due to homicides, they said.
"What we found most striking is that lifetime uncertainty has a greater association with violence than life expectancy," said Jose Manuel Aburto from Oxford's Leverhulme Center for Demographic Science.
"Lifetime uncertainty, therefore, should not be overlooked when analysing changes in mortality patterns," said Aburto, lead author of the study.
Using mortality data from 162 countries, and the Internal Peace Index between 2008–2017, the study shows the most violent countries are also those with the highest lifetime uncertainty.
In the Middle East, conflict-related deaths at young ages are the biggest contributor to this, while in Latin America, a similar pattern results from homicides and interpersonal violence, the researchers said.
However, lifetime uncertainty was "remarkably low" between 2008–2017, in most Northern and Southern European countries, they said.
The researchers found that in high-income countries, reduced cancer mortality has recently helped to reduce lifetime uncertainty.
However, in the most violent societies, lifetime uncertainty is even experienced by those not directly involved in violence.
"Whilst men are the major direct victims of violence, women are more likely to experience non-fatal consequences in violent contexts," said study co-author Professor Ridhi Kashyap, from the Leverhulme Center.
"These indirect effects of violence should not be ignored as they fuel gender inequalities, and can trigger other forms of vulnerability and causes of death," Kashyap said.
According to the study, lower life expectancy is usually associated with greater lifetime uncertainty. Living in a violent society creates vulnerability and uncertainty, and that, in turn, can lead to more violent behaviour.