A new study reveals the number of years a person stays in school is the best predictor of their longevity — more than other factors like race or ethnicity.

Each educational step a person obtained led to 1.37 years of added life expectancy on average, the study suggests.

For Brita Roy, professor at Yale University and study co-author, the education connection is a “positive finding.” It points to clear strategies that may result in measurable impacts on a person’s lifespan.

“It’s saying we have a real, concrete way to alleviate these health disparities,” Roy tells Inverse.

“There are clear changes that we can make as a society to improve educational equity. So to me, it provides some hope."

The study was published Thursday in the journal American Journal of Public Health.

Here is how the age-adjusted mortality rate per 1,000 persons breaks down by education level, according to the study:

High school or less: 61.69

Some college: 30.74

College graduates: 12.71

Chasing life

Since the late 1930s, Americans have lived longer and longer. But in 2014, this positive trend reversed, fueled by a tragic uptick in so-called "deaths of despair:" drug overdoses, suicides, and alcohol-related deaths in mid-life.

The decline in life expectancy is “truly unprecedented,” Roy says.

"No other high-income countries are experiencing such a decline.”

The downtrend points to unaddressed mental health issues in the US, as well as risk factors for poor mental health, like social isolation, she says.

"It shows that in the US, we are failing at efforts to improve health and well-being across the nation."

"A nation like ours, especially with an economy as robust as it is, we are supposed to be leading the world, supposedly, in advances in health care," she says.

To figure out whether it is possible to reverse the trend using social or demographic strategies, the researchers looked at two key influences in mortality — race and education.

Roy and her team analyzed data from a group of 5,114 black and white Americans, first recruited in 1984 from four US cities as part of the Coronary Artery Risk Development in Young Adults study. The study group is now in their mid-50s, but began the study in their early 20s. Since the study began, scientists have consistently collected each individual's demographic data, educational level, and health outcomes at different time points.

At the time of this new analysis, 395 of the total group had died — all before reaching the age of 60. In other words, these people died more than 18 years before they were expected to on average.

“The importance of this — especially in this group of people — is that all the deaths are premature. It shows how profound that early loss of life is," Roy says.

"All of these people are working-age people. Most are people with families often with relatively young children.”

Cause of death

The data reveal some striking patterns in terms of race and educational attainment. Some nine percent of black people in the study died at an early age, compared to six percent of whites. Black men were significantly more likely to die by homicide, while white men were more likely to die from AIDS. Across the group as a whole, heart disease and cancer were the most common causes of death.

But when the data were broken down by race and education, education emerged as the strongest predictor of health outcomes. People fell into one of three education categories: high school or less (less than 12 years of education), some college education (12-15 years), and college graduation (over 16 years).

About 13 percent of study participants with a high-school degree or less had died prematurely, compared to only 5 percent of college graduates.

When looking at race and education at the same time, differences related to race all but disappeared: 13.5 percent of black subjects and 13.2 percent of white subjects with a high school degree or less died during the study. By contrast, 5.9 percent of black people and 4.3 percent of whites with college degrees died.

How long people stay in school seems to matter more for longevity than their race or ethnicity, the study suggests.

"We were surprised that education completely explained the race-based disparities that we see," Roy says.

The health-education relationship may stem from a multitude of factors: People with higher levels of education also have more opportunities and higher incomes, on average. These benefits may translate to less chronic stress, a known health determinant, Roys says.

Years in school may also lead to a better understanding of lifestyle habits that translate into health like smoking, drug use, and diet.

Each level of education achieved is linked to close to a year and a half of life extension, which is “pretty significant,” Roy says.

“This is useful to know especially when we compare it to medical therapies that we certainly make a lot of money off of and are approved in the market if they increase life expectancy, even by six months.”

Investing in tested strategies to promote educational attainment, including early childhood education, programs that boost high school graduation rates, affordable housing, and policies that dismantle structural racism, results in measurable positive health outcomes, the study suggests.

But importantly, a lack of education is not a death sentence. Learning can happen at any age.

"Education is always beneficial no matter when it is obtained," Roy says. Even if someone has a high-school diploma, it is still possible to get a degree from a community college or somewhere that is affordable and feasible — an achievement that may be both beneficial for their health and for financial stability, she says.

"It's never too late. People can also take action, you know, within their communities to try to lobby for better educational opportunities for people in their communities."

Abstract:

Objectives. To assess causes of premature death and whether race/ethnicity or ed- ucation is more strongly and independently associated with premature mortality in a diverse sample of middle-aged adults in the United States.

Methods. The Coronary Artery Risk Development in Young Adults study (CARDIA) is a longitudinal cohort study of 5114 participants recruited in 1985 to 1986 and followed for up to 29 years, with rigorous ascertainment of all deaths; recruitment was balanced regarding sex, Black and White race/ethnicity, education level (high school or less vs. greater than high school), and age group (18–24 and 25–30 years). This analysis included all 349 deaths that had been fully reviewed through month 348. Our primary outcome was years of potential life lost (YPLL).

Results. The age-adjusted mortality rate per 1000 persons was 45.17 among Black men, 25.20 among White men, 17.63 among Black women, and 10.10 among White women. Homicide and AIDS were associated with the most YPLL, but cancer and car- diovascular disease were the most common causes of death. In multivariable models, each level of education achieved was associated with 1.37 fewer YPLL (P = .007); race/ ethnicity was not independently associated with YPLL.

Conclusions. Lower education level was an independent predictor of greater YPLL.