Despite being home to some of the world’s most dangerous animals, Australia has had the highest life expectancy in the English-speaking world over the past three decades. As for other high-income English-speaking countries, the Irish have seen the largest gains in life expectancy, while Americans have ranked last since the early 1990s, according to a team of social scientists led by a Penn State researcher.

The team published its results in the journal BMJ opened.

“One lesson we Americans can learn about life expectancy by looking at comparable countries is where the limit of best performance is,” said Jessica Ho, associate professor of sociology and demography at Penn State and lead author of the study. “Yes, we’re doing poorly, but this study shows what we can aspire to. We know that these increases in life expectancy are actually achievable because other major countries have already done it.”

The researchers compared life expectancy in the United States, Canada, Ireland, the United Kingdom, Australia and New Zealand using data from the Human Mortality Database and the World Health Organization Mortality Database between 1990 and 2019. They analyzed the data by sex, age and 18 individual and comprehensive cause of death categories, including cancer, drug and alcohol-related deaths, firearms and motor vehicle accidents.

They also examined life expectancy within each country to identify geographical inequalities in life expectancy by region.

The researchers found that Australians had the highest life expectancy at birth during the study period: women lived almost 4 years longer and men 5 years longer than their American counterparts. The Irish had the largest increases in life expectancy: men’s life expectancy increased by about 8 years and women’s by more than 6.5 years. Americans had the shortest life expectancy at birth: women lived an average of almost 81.5 years in 2019 and men an average of almost 76.5 years.

According to the researchers, the United States also had the greatest geographic inequalities in life expectancy compared to other countries. Women and men in California and Hawaii had some of the highest life expectancies at birth, with women averaging 83 to 83.9 years and men 77.5 to 78.4 years. States in the American Southeast had some of the lowest life expectancies at birth of all the subnational regions studied, with women averaging 72.6 to 79.9 years and men 69.3 to 74.4 years.

“One of the main reasons life expectancy in America is so much lower than in other high-income countries is that our younger people are dying more often from largely preventable causes of death, such as drug overdoses, car accidents and homicide,” said Ho, who is also a fellow at the Social Science Research Institute at Pennsylvania State University.

In midlife – between ages 45 and 64 – some of these causes remain, such as high death rates from drug and alcohol use, Ho explained, adding that death rates from cardiovascular disease are also higher in the United States.

“Some of the latter may be related to a sedentary lifestyle, high obesity rates, unhealthy diet, stress and a history of smoking,” she said. “It is likely that these patterns of unhealthy behaviors put Americans at a disadvantage in terms of their health and vitality.”

Australia offers the US a model for improving life expectancy, Ho added. Like the US, Australia is large in area and has a similar history of private vehicle ownership. The two countries share some cultural similarities, including historically higher use of firearms. However, Australia has implemented a number of policies in recent decades, including gun law reforms, that have helped catapult the country to the top of the life expectancy rankings.

“The study shows that a comparable country like Australia far outperformed the United States in bringing young adult mortality rates under control,” Ho said. “There are very few firearm deaths and homicides, less drug and alcohol use, and better chronic disease outcomes. The latter points to lifestyle factors, health behaviors, and health care performance.”

Ho said measures such as investing in public transit infrastructure, building more roundabouts and putting fewer large cars on the road could reduce traffic deaths in the U.S. More support for programs to reduce drug addiction and lower barriers to treatment and prevention of drug overdoses could help reduce drug-related mortality, she said. And a strong combination of public health measures, access to health care and community action to promote healthier lifestyles and the use of preventive medicine could reduce mortality from cardiovascular disease, she added.

“Australia is a model of how Americans can do better and achieve not only higher life expectancy but also lower geographic inequality in life expectancy,” Ho said.

Rachel Wilkie, a doctoral student at the University of Southern California, also contributed to this research.