After examining decades of data, researchers from the University of Colorado Denver have found that a lack of education may be as deadly as smoking.

The study, which included researchers from New York University and the University of North Carolina at Chapel Hill, examined population data going back to 1925 to determine how education levels affected mortality over time.

They found a direct link between education levels and death, noting that higher education is a strong predictor of longevity due to factors that include higher income, healthier behaviors and improved social and psychological well-being.

"Our results suggest that policies and interventions that improve educational attainment could substantially improve survival in the U.S. population, especially given widening educational disparities," said study co-author Patrick Krueger, PhD, assistant professor in the Department of Health&Behavioral Sciences at the University of Colorado Denver, a major center of timely, topical and relevant research, and the Institute of Behavioral Sciences at the University of Colorado Boulder. "Unless these trends change, the mortality attributable to low education will continue to increase in the future."

According to the research, low education levels are common in the U.S. with more than 10 percent of adults between the ages of 25 and 34 lacking a high school degree and another 28.5 percent having some college but no bachelor's degree.

Using the Centers for Disease Control and Prevention's National Health Interview Survey data from 1986-2006, Krueger and his colleagues, including CU Denver PhD student Melanie Tran, studied over a million people to estimate the number of deaths attributable to low levels of education among those ages 25 to 85 in 2010.

They discovered that 145,243 deaths could have been saved in 2010 if adults who had not completed high school had gone on to earn a GED or high school degree. That's comparable to the estimated number of deaths that could be averted if all current smokers had the mortality rates of former smokers. In addition, 110,068 deaths could have been saved if adults who had some college went on to complete their degree.

Krueger and his colleagues also examined data for those born in 1925, 1935 and 1945 to see how education levels impacted mortality over time.

They found that disparities in mortality across different education levels widened substantially over time. For example, mortality rates fell modestly among those with high school degrees, but much more rapidly among those with college degrees.

Healthy People 2020 - an initiative to improve Americans' health decade by decade - set goals for increasing the proportion of students completing high school by 2020. The researchers said that based on their findings, meeting these goals could have a substantial impact on future survival patterns.

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

The bottom line, Chang said, "is paying attention to education has the potential to substantively reduce mortality."

Citation: Krueger PM, Tran MK, Hummer RA, Chang VW (2015) Mortality Attributable to Low Levels of Education in the United States. PLoS ONE 10(7): e0131809. doi:10.1371/journal.pone.0131809