Professors Anne Case and Angus Deaton wrote the study.
It finds that men and women older than 45 but younger than retirement age are dying from what one expert calls "deaths of despair." These include deaths from suicide, drug overdose or alcohol-related diseases.
They say this is caused by the loss of middle-income jobs for those without a college degree.
The economists also say that fewer job opportunities have created other problems for this group. The researchers say they are more likely than those with college degrees to be unemployed, unmarried or suffer from poor health.
"This is a story of the collapse of the white working class," Deaton said in an interview. "The labor market has very much turned against them."
The study continues research in 2015 that first documented an increase in deaths among middle-aged whites.
A sharp increase in “deaths of despair”
Case and Deaton found that since 1999, white men and white women ages 45 through 54 have suffered from a sharp increase in "deaths of despair." These include suicides, drug overdoses, and alcohol-related deaths, such as liver failure.
Case and Deaton say in their study that there is a relationship between rising death rates and changes in the job market since the 1970s.
They said that men without college degrees are less likely to receive better pay over time, a trend "consistent with men moving to lower and lower skilled jobs."
Other research has found that Americans with only high school educations are less likely to get married or buy a home. They are also more likely to get divorced if they do marry the study says.
"It's not just their careers that have gone down the tubes, but their marriage prospects, their ability to raise children," said Deaton.
"That's the kind of thing that can lead people to despair."
Angus Deaton won the Nobel Prize in economics in 2015 for using surveys to study how people spend their money and to learn more about their behavior.
White Americans are the most affected
The issues identified by Case and Deaton may be causing a change in the trend of improving life expectancies. However, the researchers say it is not clear why these problems are affecting whites more than African-Americans or Hispanics.
Case and Deaton note that many Hispanics are in a much better situation than their parents or grandparents, who were born in another country. This could create a greater sense of optimism.
The professors also added that African-Americans may have become more resilient to economic difficulties because they have a long history of suffering problems in the job market.
The researchers also noted that a life expectancy division among people with different education levels is growing. While death rates for middle-aged whites without a college degree are rising, the Princeton professors say the rates for whites with a college education are falling.
These trends, the researchers say, are found across the United States. West Virginia and Kentucky are reportedly most affected.
However, areas such as the state of Maine, the city of Baltimore and eastern Washington state also appear to show the trends identified in the study.
The research also found these trends exist in rural areas, in small cities and in some large urban areas.
Case and Deaton say death rates for middle-aged people in Europe with limited education are falling. And they add that this is the case in most countries.
Case and Deaton also note that government programs to help people with disabilities are not responsible for the increase in middle-aged deaths. Some of these programs, the researchers say, are permitting more Americans to stop working.
They say that social programs in Europe usually provide more benefits than the ones in the U.S. And the researchers say Europe has not seen a similar increase in middle-aged deaths.
Case and Deaton say that changing these trends could take years. To help prevent middle-aged deaths, they say, doctors should cut back on providing opium-based pain drugs to patients.
The study was published in Proceedings of the National Academy of Sciences of the United States. It also appears on the website of The Brookings Institution, a public policy organization.
Words in This Story
demographic - n. the qualities such as age, sex, and income of a specific group of people
despair - n. the feeling of no longer having any hope
epidemic - n. an occurrence in which a disease spreads very quickly and affects a large number of people
gone down the tubes - to fail completely
overdose - n. an amount of a drug or medicine that is too much and usually dangerous
resilient - adj. able to become strong, healthy, or successful again after something bad happens