Last month, for the first time in four years, the World Health Organization quietly published new data on the healthy life expectancies of every country in the world, bringing us new healthy life expectancy numbers for 2019 and updated numbers for 2010 and 2015.

Healthy life expectancy, often referred to as health span, measures how long people within a population are expected to live without disease or disability. For example, if I live disease-free until the age of 100, at which point I am diagnosed with debilitating Alzheimer’s disease, and live with that dementia until my death six years later, my healthy life expectancy would be 100, whereas my total life expectancy would be 106.

Whereas total life expectancy primarily measures how long we can keep sick people alive, and incentivizes our health system to manage disease, healthy life expectancy is one of the most important measures to track and improve as it directly relates to how many years of happy, healthy life we are living, and incentivizes our health system to prevent disease from occurring in the first place.

So what does the latest data say about how much longer we’re living? On the bright side, the huge majority of countries are living longer, healthier lives. However, here comes the bad news for Americans:

The U.S. is the only developed country in the world that has experienced a decrease in healthy life expectancy in any period since 2010.

It gets worse.

There are only three major countries in the world that have experienced a decrease in life expectancy in both of the last measurement periods, and the U.S. is one of them, along with developing countries Yemen and Venezuela.

The back-to-back decrease in healthy life years of Yemen and Venezuela (in red) is easily attributed to early death, injury, and disability as a result of war and economic collapse, with an ongoing civil war in Yemen and a decade-long humanitarian crisis in Venezuela, but the U.S. has no such excuse.

Other conflict countries like Libya, Syria, Iraq, and Honduras (in yellow) have experienced acute drops in healthy life expectancy as a result of violent conflict, but bounce right back to increasing healthy life years in the next measurement period, whereas the U.S., even with no civil war claiming the lives of millions of young people, has continued its health decline.

Every population in the world, from Qatar to Australia, is expanding its years of healthy living, except for the world’s most powerful country and some of the world’s most war-torn countries.

As an American, hearing that we are the only developed country with decreasing healthy life expectancy, you might think that the reason for our decline is because we’re already so far ahead of the pack that we have nowhere to go but down, that our healthy life expectancy decrease is the inevitable result of being #1 and already pushing the limits of biology. That assumption would be gravely misguided. The average U.S. healthy life expectancy of 66.1 years is ranked last among developed countries, and among all countries is ranked just below Iran, Trinidad and Tobago, and North Macedonia. The longest lived country, Japan, enjoys eight more years of healthy life than the average American.

To reiterate, not only is the U.S. enjoying fewer healthy years of life compared to other developed countries, we are alarmingly not improving, year after year. In other words, while most countries are doing well and getting even better, the U.S. is doing badly and getting even worse.

The irony of the U.S.’s situation is that it is the richest country in the world (in total GDP) and one of the richest in per capita GDP. While a country’s healthy life expectancy typically improves as a result of higher GDP, the U.S. has experienced the opposite result in recent years. Our GDP increases, yet our years of healthy life remain on the decline.

Our neighbor in the bottom-right quadrant, Qatar, also has a lower-than-expected healthy life expectancy for its GDP per capita, but unlike the U.S., Qatar’s healthy life years are rising rapidly. In fact,  Qatar has the fastest growing life expectancy among high-income countries.

The USA, ranking near last in the world in healthy life trajectory, is paradoxically the most powerful country in the world. With power comes responsibility, and we have a responsibility to heal our people and extend our years of happy, healthy life.

Unfortunately, we’re optimizing for the wrong metric. Healthy life expectancy is often overshadowed by total life expectancy. But total life expectancy is a vanity metric. When optimizing for total life expectancy, the only chart that shows upward growth is years living with disease.

As we’ve seen, other countries experience the occasional year of worsening healthy life expectancy, as a result of extreme events like civil war, on an otherwise upward healthy trajectory. The U.S. has no such civil war. Our citizens, both the elderly and, sadly, young people, are being killed not by bombs and bullets, but by drugs and disease. Our physical and mental health issues stretch far beyond violent conflict and civil unrest. But maybe the issues we face do warrant civil unrest. Maybe we should fight a war, and declare an enemy. That enemy would not be against an opposing group of people, but rather against the mechanisms in our society that cause chronic disease and poor mental health, often as a result of inequality and negative externalities left unchecked.

I’m a glass-half-full type of guy. But it’s impossible to ignore some data that have such massive implications and leave me feeling empty. The U.S., in many ways, is still the envy of the world, and in many other ways, has already started its slow decline into irrelevance. A nation’s health starts with the health of its people. Without that healthy foundation, we will inevitably crumble.