What's in a number? Looking at life expectancy in the US

If you were to sum up the overall health of a nation in one single number, what would that be? At the top of the list, you would likely find average life expectancy — the total number of years, on average, that a person in a country can expect to live. Wars, famine, and economic crises are expected to lower life expectancy. Breakthroughs in science, strong economies, and behaviors like eating a healthy diet, exercising, and avoiding tobacco typically raise average life expectancy.

An amazing rise, a surprising fall

Between 1959 and 2014, the United States experienced an unprecedented increase in life expectancy, which rose from 69.9 years to 78.9 years. The simple thought of adding almost 10 years, on average, to the lifespan of each individual in the country in that short amount of time is amazing and astounding, a true testament to our rapidly increasing understanding of health, medicine, and the environment.

Unfortunately, that's where the good news ends. Between 2010 and 2014, life expectancy in the US plateaued. And then in 2014, something worse happened: life expectancy began decreasing. The US experienced three years in a row of declining life expectancy. As an article in the Washington Post observes, this is the first time the US has seen such prolonged declines since 1915 to 1918, when Americans experienced both World War I and a flu pandemic. The US is also the only developed country in the world whose average life expectancy stopped increasing after 2010. We now rank 35th in the world. The average American can expect to live 3.5 years less than the average Canadian. So now, in this decade, without large-scale war causalities or a severe pandemic, without economic crisis or famine, why is US life expectancy decreasing?

Diving into details on life expectancy

A recent report in JAMA provides a comprehensive, detailed look at this phenomenon. The authors focused attention on midlife, defined as adults ages 25 to 64. Midlife is the time when adults are typically the most productive, raising families and making up the majority of the workforce. Tragically, mortality rates in this age group are bringing down the national average. Key findings below help explain why.

(First, a quick note about percentages: A 100% increase in deaths from an illness means the death rate doubled since the last time it was measured. A 400% increase means deaths are five times as high as they were previously.)

Certain health problems are driving higher death rates. Since 1999, the US has seen drastic decreases in deaths due to heart disease, cancer, HIV, and motor vehicle injuries. But since 1999, drug overdose deaths in midlife increased almost 400%, while deaths from alcoholic liver disease and suicide increased by about 40% each. Likewise, deaths caused by illnesses related to high blood pressure increased by nearly 80%, while those from obesity-related illness rose 114%.

Gender matters. Overall, men have lower life expectancy than women. Likewise, during midlife men were more likely than women to die from most causes, with some important exceptions. For example, overdose deaths nearly quadrupled overall, but among women the increase was 1.4 times higher than among men. And deaths related to alcoholic liver disease were 3.4 times higher among women than men.

Race and ethnicity matter. Since 1999, nearly all racial and ethnic groups have experienced an initial improvement in life expectancy followed by a decline. Only non-Hispanic American Indians and Alaska Natives did not experience a decline. Death rates of non-Hispanic black individuals in midlife have remained substantially higher compared with non-Hispanic white people over the past decades. But for certain conditions the disparities are even greater, including a relative increase of over 170% in fatal drug overdoses between 2010 and 2017.

Where you live matters. One of the most fascinating parts of the report is the state-by-state mortality comparison. The difference in mortality between the highest and lowest life expectancy states is seven years! Furthermore, there has been a shift over the past decades. For example, in 1959, Kansas had the highest life expectancy, but in 2016 it ranked 29th. There were also differences between neighboring states: Alabama and Georgia had a negligible (0.1 year) difference in 1990, but by 2016, Georgia's life expectancy was 2.3 years greater. And finally, states who have been hit hardest with the opioid overdose epidemic have also seen decreases in life expectancy, particularly those in New England and the Ohio Valley. In fact, the authors of the report calculated that there were over 33,000 excess deaths from 2010 to 2017. About a third of these deaths occurred in just four Ohio River Valley states: West Virginia, Ohio, Indiana, and Kentucky.

Life expectancy is much more than just a number

In unpacking this important report, so many unanswered questions rise to the surface. I think of the potential every child has, and the years of people's lives that are lost unnecessarily and prematurely, especially during midlife years when they could be most productive. There is, fortunately, a glimmer of a silver lining: a new report shows that, in 2018, life expectancy increased in the U.S. by 0.1 years — so, just over five weeks.

Still, what would our country's average life expectancy be if we could eliminate stigma around addiction, increase treatment resources, and end overdose-related deaths? What would the number be if every American was guaranteed access to inexpensive medicines for chronic conditions such as high blood pressure? If we recognized that mental illness is a chronic disease and people had access to appropriate behavioral health services? If our society addressed the social determinants of health, focusing on vast disparities between racial and ethnic groups, as well as rural and city inhabitants? I can't tell you the answers. But as a nation, we must address these tough questions if we wish to resume our once remarkable progress extending people's lives.