The US has the lowest life expectancy of its peer countries. One chart shows how other nations compare.

• The average life expectancy in the US has declined again — on track for the sharpest drop since 1921-23.
• Compared to people in other large, wealthy nations, Americans tend to have lower life expectancies.

Life expectancy in the US has dropped to a low not seen in this millennium, according to data from the Centers for Disease Control and Prevention (CDC).

In 2020, life expectancy at birth declined to 77 years — the lowest national average since 1996. Projections for 2021 showed another drop to 76.1 years, which would be the biggest two-year downturn in US life expectancy since 1921-1923, according to the CDC's National Center for Health Statistics.

Compared to similarly large and wealthy nations, the US has seen its average life expectancy dwindle over the past several decades. Life expectancy in the US has increased by smaller amounts than in peer countries since 1980 — and the COVID-19 pandemic may have widened that gap, based on provisional estimates from Kaiser Family Foundation.

The US average ranks lower than the average life expectancy across peer countries in the Organisation for Economic Co-operation and Development (OECD), and it's also lower than the average for the entire European Union. Differences in healthcare may explain why Americans tend to die earlier.

Americans pay more for healthcare compared to other high-income populations

According to The Commonwealth Fund, the US is the only high-income country that does not have some form of universal health insurance.

Nearly 30 million Americans are uninsured and about 40 million are not fully covered by their health plans, leaving them at risk of prohibitive costs. For context, the US population is estimated to exceed 332 million in 2022.

Most of the countries with the highest life expectancies offer near-universal coverage for all kinds of medical care, including primary care and hospital care. Some countries offer these services at no cost to the individual, while other nations have created annual caps on how much a person can pay out-of-pocket.

Peer countries like Switzerland and Sweden have fixed annual out-of-pocket maximums that limit how much individuals pay for healthcare. According to the Borgen Project, people in Sweden do not pay for medical consultations after they reach a cap of about $125 USD.

The US population is also sicker, on average

As gaps in health insurance leave some Americans unable to afford preventive and primary medical care, the population has become sicker as a whole.

Compared to other high-income countries, the US population has a higher prevalence of chronic conditions like obesity, diabetes, heart disease, and respiratory ailments. When combined with limited access to care, people in the US tend to die of these conditions earlier, and they are left more vulnerable to other health threats.

The COVID-19 pandemic showed just how difficult it is to achieve good healthcare outcomes when the population is sicker to begin with and has insufficient access to preventive and primary care. The US had a far higher death toll compared to peer countries; it surpassed the UK and Belgium to have the largest share of its population die from COVID over the entire pandemic, the New York Times reported.

Japan has invested in preventive medicine

Japan tends to top global life expectancy rankings, with a 2020 average of 85 years from birth.

The nation's high life expectancy is usually attributed to a low rate of obesity, healthy diet, and preventive medicine. Compared to similar countries, Japan has fewer deaths from ischemic heart disease and cancers, particularly breast and prostate cancer, according to the Cardiology Institute of Montreal.

Diet is an important element of Japan's preventive approach to healthcare. The population has a much lower rate of red meat consumption compared to the US and tends to eat a lot of fish and plant foods, such as soybeans and tea.

According to Aetna, Japan not only has instituted campaigns to reduce salt consumption and moderate blood pressure with medication, but also boasts strong childhood vaccination programs and universal health insurance. Japan's aging population is also known for staying active, which may contribute to better health for the elderly.