A Potential Decline in Life Expectancy in the United States in the 21st Century

For the past 100 years or so, there has been a general trend toward increasing life expectancy in developed countries. In this Special Report, the authors argue that obesity, and perhaps infectious diseases, will lead to a decrease in life expectancy in the 21st century. In this Special Report, the authors argue that obesity, and perhaps infectious diseases, will lead to a decrease in life expectancy in the 21st century. The trend in the life expectancy of humans during the past thousand years has been characterized by a slow, steady increase 1 , 2 — a pattern frequently punctuated by a volatility in death rates caused by epidemics and pandemic infectious diseases, famines, and war. 3 , 4 This volatility was dramatically curtailed in the mid-19th century as infectious diseases yielded swiftly to improved living conditions, advances in public health, and medical interventions. During the past 30 years, the rise in life expectancy at birth in the United States decelerated relative to this historical pattern, and gains in life expectancy at older ages are . . .