The first decline since 1993 is likely being driven by multiple factors, including obesity. 

The world has benefited from some amazing advances in healthcare — beginning with the dawn of the Vaccine Age over a century ago—that have contributed to longevity. During the 20th century, life expectancy at birth among US residents increased by 62%, from 47.3 years in 1900 to 76.8 in 2000, and unprecedented improvements in population health status were observed at every stage of life, according to the US Centers for Disease Control and Prevention.

But a report released Thursday by the National Center for Health Statistics suggests we are starting to lose precious ground. For the first time in more than two decades, life expectancy for Americans declined. Granted, the change may appear incremental—78.9 years in 2014 to 78.8 years in 2015—but it’s enough to make you pause and wonder what’s going on and will this be a trend. It does not seem to be occurring in other Western countries.

“A 0.1 decrease is huge,” Peter Muennig, a professor of health policy and management at Columbia University’s Mailman School of Public Health, told the New York Times this week. “Life expectancy increases, and that’s very consistent and predictable, so to see it decrease, that’s very alarming.”

Fatalities increased in nearly every disease in the Top Ten—with the biggest jump occurring in people with Alzheimer’s. The only disease that saw a decline in deaths was cancer, probably because of the decline in smoking.

Experts aren’t sure what to make of the statistics. Some believe an increase in reporting is boosting the death rates, others think the epidemic of obesity—36% of adult Americans are overweight and 6.3 percent are extremely overweight—are causing a decline in the national health profile.   

Here is a copy of the report and here are articles in the Washington Post and New York Times offering perspectives from the scientific community.