The overall mortality rate in the United States declined markedly over the 20th century, resulting in large gains in life expectancy. In 1900, the average U.S. newborn could expect to live to 47.3 years of age. In 2010, they could expect more than 30 additional years of life, with a life expectancy at birth of 78.7.
In 1900, the top 3 causes of death were infectious diseases—pneumonia and flu, tuberculosis, and gastrointestinal infections (a fourth infectious disease, diphtheria, was the 10th leading cause of death). Improvements in sanitation, public health (vaccination development and delivery), and medical treatments, such as antibiotics, led to dramatic declines in deaths from infectious diseases during the 20th century. As the impact of these diseases has been reduced or eliminated, mortality rates from other causes, especially chronic diseases, such as heart disease and cancer, have increased, and new diseases, such as noninfectious airways diseases, diabetes, and suicide, are now among the top 10 causes of death.
Click on an image to examine trends in leading causes of death in 1900 versus 2010:
Writing about the changing burden of diseases in the 200th anniversary issue of the New England Journal of Medicine, doctors David Jones, Scott Podolsky, and Jeremy Greene note that, throughout the 20th century, “Optimism about prospects for the health of future populations persisted but remained tempered by concern about the pathologies of civilization.” In addition to the emergence of new diseases and public health challenges, such as HIV/AIDS and obesity, old challenges persist.
Although mortality from infectious diseases declined dramatically, the emergence of chronic (HIV/AIDS) and drug resistant (TB) infectious diseases reminds us that infectious diseases are “volatile” by nature and highlights the importance of being “vigilant over the threats posed by microbes.” In spite of the changing nature of disease, health inequalities in disease burden and mortality persist. Jones and colleagues remind us that these disparities are challenges to both “our scientific knowledge and political will.”
Genetic variations don’t explain why mortality rates double as you cross Boston Harbor from Back Bay to Charlestown or walk up Fifth Avenue from midtown Manhattan into Harlem…. Disparities in health and disease are outcomes that are contingent on the ways society structures the lives and risks of individuals.