Staying in school has not only financial advantages, but also health benefits: A new study estimates that more than 145,000 deaths per year could be averted in the United States if everyone who didn't finish high school had earned their high school degrees.

That estimate is on a par with the number of deaths that could be avoided each year if all U.S. smokers were to quit smoking, the researchers said.

The findings suggest that U.S. policies aimed at increasing people's education level could improve residents' longevity, the researchers said.

"In public health policy, we often focus on changing health behaviors such as diet, smoking and drinking," study co-author Virginia Chang, an associate professor of public health at New York University's Steinhardt School of Culture, Education, and Human Development, said in a statement. "Education —which is a more fundamental, upstream driver of health behaviors and disparities — should also be a key element of U.S. health policy."

People with higher levels of education may live longer for many reasons, including that they tend to have higher incomes, healthier behaviors and better psychological well-being, the researchers said.

For the study, the researchers followed more than 1 million people between 1986 and 2006, looking at their education levels and death rates. They also used information from people born in 1925, 1935 and 1945 to determine how education levels affect death rates over time. [5 Surprising Ways to Be Heart Healthy]

They estimated that, in 2010, 145,243 deaths could have been averted if people who didn't finish high school had instead earned either their GED or a high school degree, and an additional 110,068 deaths could have been averted if people who started college but dropped out had instead gone on to earn their bachelor's degree.

The researchers also found that, between 1925 and 1945, death rates fell among people of all education levels, but they fell much faster among people with college degrees. As a result, the gap in mortality rates among people of different education levels grew over time.

"Unless these trends change, the mortality attributable to low education will continue to increase in the future," said study co-author Patrick Krueger, assistant professor in the Department of Health & Behavioral Sciences at the University of Colorado, Denver.

People with more education are less likely to smoke, more likely to engage in vigorous exercise and more likely to have access to health insurance. In addition, studies suggest that the advances in the treatment and prevention of heart disease in recent decades were reaped mainly by people with more education, the researchers said.

The study is published today (July 8) in the journal PLOS ONE.

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