Global lifetime uncertainty (standard deviation) and level of violence (GPI Internal Peace) for men and women conditional on surviving to age 10 in 2017. Credit: NYU Abu Dhabi

How long people live is less predictable and life expectancy for young people can be as much as 14 years shorter in violent countries compared to peaceful countries, according to a new study today from an international team, led by Oxford's Leverhulme Center for Demographic Science. It reveals a direct link between the uncertainty of living in a violent setting, even for those not directly involved in the violence, and a "double burden" of shorter and less predictable lives.

According to the research, are responsible for a high proportion of the differences in lifetime uncertainty between violent and peaceful countries. But, the study says, "The impact of on mortality goes beyond cutting lives short. When lives are routinely lost to violence, those left behind face uncertainty as to who will be next."

Lead author Dr. José Manuel Aburto from Oxford's Leverhulme Center for Demographic Science and the London School of Hygiene and Tropical Medicine, adds, "What we found most striking is that lifetime uncertainty has a greater association with violence than life expectancy. Lifetime uncertainty, therefore, should not be overlooked when analyzing changes in mortality patterns."

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.

But lifetime uncertainty was "remarkably low" between 2008–2017, in most Northern and Southern European countries. Although Europe has been the most peaceful region over the period, the Russian invasion of Ukraine will impact this.

Explainer video. Credit: Filmed by Vanessa di Lego, Vienna Institute of Demography at the Austrian Academy of Sciences. Edited by Leverhulme Centre for Demographic Science.

In high-income countries, reduced cancer mortality has recently helped to reduce lifetime uncertainty. But, in the most violent societies, lifetime uncertainty is even experienced by those not directly involved in violence. The report states, "Poverty-insecurity-violence cycles magnify pre-existing structural patterns of disadvantage for women and fundamental imbalances in gender relations at young ages. In some Latin American countries, female homicides have increased over the last decades and exposure to violent environments brings health and social burdens, particularly for children and women."

Study co-author Professor Ridhi Kashyap, from the Leverhulme Center, says, "Whilst men are the major direct victims of violence, women are more likely to experience non-fatal consequences in violent contexts. 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."

According to the report, lower life expectancy is usually associated with greater lifetime uncertainty. In addition, living in a violent society creates vulnerability and uncertainty—and that, in turn, can lead to more violent behavior.

Countries with high levels of violence experience lower levels of life expectancy than more peaceful ones, "We estimate a gap of around 14 years in remaining life expectancy at age 10 between the least and most violent countries…In El Salvador, Honduras, Guatemala and Colombia the gap in with is predominantly explained by excess mortality due to homicides."

Study co-author Vanessa di Lego, from the Wittgenstein Center for Demography and Global Human Capital, adds, "It is striking how violence alone is a major driver of disparities in lifetime . One thing is for certain, global violence is a public health crisis, with tremendous implications for population health, and should not be taken lightly."

More information: José Aburto, A global assessment of the impact of violence on lifetime uncertainty, Science Advances (2023). DOI: 10.1126/sciadv.add9038. www.science.org/doi/10.1126/sciadv.add9038

Journal information: Science Advances