Friday, December 9, 2016

Life expectancy declines in the U.S.

Life expectancy is defined as the number of years a person born in any given year can expect to live, on average.  It's commonly used to as a comparative measure of the health of a population over time, or to compare different populations.

In the past, life expectancy in the U.S. generally rose year-over-year as health care improved and the U.S. became more safety-conscious (the requirement that we use seat belts while driving, for example).  But now the Centers for Disease Control & Prevention (CDC) reports that life expectancy actually declined in 2015. A person born in 2015 can expect to live 78.8 years, on average - down from 78.9 years in 2014.

A decline of only 0.1 years doesn't sound like much, and indeed it isn't.  But life expectancy in the U.S. has risen steadily and consistently for over 45 years, so 2015 represents a noticeable change.  The only other year in those 45 years that life expectancy declined was 1993, at the height of the HIV/AIDS epidemic.

This time around, there doesn't seem to be just one obvious cause.  In 2015, eight of the ten top causes of death (including suicides and accidents, as well as chronic diseases such as heart disease and diabetes) showed an increase in death rates.  If life expectancy continues to decline in future years, health officials will have to dig deeper to try to discern the cause.  For now, a wait-and-see approach seems most appropriate.

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