It’s a grim fact of life in the United States: Children born into poor families are sicker and die earlier than their well-off counterparts, particularly from obesity-related diseases such as heart attack and stroke. Now, new data from a famous North Carolina study of early childhood education suggest that such disparities are not carved in stone. Children who grew up poor but participated in an intensive, 5-year day care program are significantly healthier in their mid-30s than similarly impoverished children who did not receive the same care, researchers report. The study provides rare experimental evidence that such programs can give poor children a better shot at living longer, healthier lives.

Launched in 1972 at the University of North Carolina (UNC), Chapel Hill, the Carolina Abecedarian Project is one of the longest running studies on the benefits of early childhood education for low-income children. The original goal of the research was to see if it was possible to enhance IQ and school readiness among poor children at high risk of falling behind as they transitioned into grade school, says UNC Chapel Hill psychologist Frances Campbell, who joined the study decades ago as an evaluator. “No one could see anything wrong” with these infants, she says, “but then they’d get to school and fall flat.”

By posting notices in social service offices and low-income health clinics around Chapel Hill, researchers recruited families with 2-month-old babies for the study. The majority of the more than 100 infants that participated were African-American, mostly born to low-income mothers who had not graduated from high school. Many of the mothers had nowhere to send their children during the day while they worked, Campbell says.

All infants received nutritional supplements, basic social services, and access to health care. Half, however, were randomly assigned to attend a day care program near the Frank Porter Graham Elementary School, part of a child development research institute at UNC Chapel Hill. There, they received nearly constant attention from trained caregivers for 6 to 8 hours per day, 5 days per week. In addition to carefully supervised nutrition and medical care, the children were constantly picked up, played with, and talked to, Campbell says. Being one of the caretakers, she says, was “the best job you can imagine.”

The project was expensive: With a starting teacher-child ratio of about 1-to-3 in the nursery and 1-to-6 in the final year of instruction, the intervention ultimately cost about $70,000 a head over 5 years. Over time, however, the study began to yield encouraging results that led many to say the expense was justified. Once they reached school age, the children who had received the intervention consistently performed in reading and math about one grade level higher than the control group. By age 21, the education gap between the groups had widened further, affecting income status: The treated group was four times more likely to have graduated from college by age 21, for example, and roughly 30% more likely to be employed in a skilled job.

The success of the Abecedarian Project and several other similar experiments made most people think of early childhood education as an academic, rather than a health, intervention, says James Heckman of the University of Chicago in Illinois, a Nobel Prize-winning economist. Although there is “strong evidence” that education later in life promotes health, the link between health and education prior to age 4 to 5, when most children enter preschool, had not been widely explored, he notes. “Never does anybody say that such interventions are going to have a huge effect on the health care budget.”

For the new study, Campbell, Heckman, and colleagues hired a physician to examine all of the participants still left in the North Carolina trial, taking blood pressure and other measurements when they were in their mid-30s. (The physician was blind to whether the participants had been in the day care or not.) Because a large number of participants had dropped out of the study by that time, the team devised a series of stringent statistical tests to “kick the tires” and ensure their results were robust, he says.

Striking health differences emerged from the data, the team reports online today in Science. Most dramatic, in Heckman’s view, were differences in systolic and diastolic blood pressure among 12 men who had received the intense care and the 20 men who hadn’t. On average, the control group had stage 1 hypertension, which significantly increases risk of heart attack and stroke. In contrast, the average blood pressure for men who had been in the day care program as children was in the normal range.

In addition to high blood pressure, roughly a quarter of men in the control group also had “metabolic syndrome,” a constellation of symptoms including excess abdominal fat and high blood sugar, says health economist Gabriella Conti of University College London, who also contributed to the study. In contrast, “no one” in the treatment group had metabolic syndrome, she says.

The new study is “extremely solid,” and suggests that it is possible to prevent conditions such as obesity and heart disease in the poor, a population that has long been thought “impossible to reach,” says David Rehkopf, a social epidemiologist at Stanford University in California. That could have profound economic implications, Heckman says. Although it isn’t yet complete, Seong Moon, an economist at the University of Chicago, is conducting a cost-benefit analysis based on the new results that looks “quite promising,” Heckman notes.

The major unknown remains: why those who received the extra attention enjoy better health, says Heather Royer, an economist at the University of California (UC), Santa Barbara. Was it better nutrition and medical care, or simply that participants who went through the day care program make more money and enjoy better health care, for example? The researchers couldn’t tease out a clear reason because the day care program included so many components and involved such a small number of participants, Heckman says.

“We all sense that what happens in early childhood really matters for adult health,” but the challenge of conducting randomized, controlled studies to illustrate that makes evidence like this rare, says Nancy Adler, a psychiatrist at UC San Francisco and an expert on how socioeconomic status influences health. Despite spending more on health care than other countries, the United States has poorer health outcomes than other nations that spend less, she says. One reason for that may be that the United States underinvests in social services, especially during early childhood, and that we’re “paying the price later on” in consumption of health care services, she says. The new results from the Abecedarian Project do “argue for policy interventions in early childhood,” she says.

Still, although he considers the findings “amazing,” Bruce Link, an epidemiologist at the Columbia University Mailman School of Public Health in New York City, cautions that there’s no guarantee that the relatively small study will translate seamlessly into good policy. “Just knowing that this has a causal effect on health in this study doesn’t mean it would work out on a population level.”