When the Centers for Disease Control and Prevention (CDC) launched research in the 1990s into the relationship between traumatic experiences in childhood and health problems in adulthood, they first focused on mental health outcomes and health problems that stemmed from poor lifestyle choices.
Those choices included smoking, drinking, and bad eating habits, made more likely by abuse or neglect in childhood.
But as the research gathered steam, an interesting pattern emerged.
Adverse childhood experiences (ACE) correlated with higher risk for disease later in life well beyond mental health conditions. The risks remained even when researchers filtered out risky behaviors like smoking, drinking, and diet.
The connection wasn’t just behavior; it was also biology.
The discovery launched a whole new field of inquiry into how an event could spur illness decades later and which diseases might therefore be better understood as developmental disorders, according to Dr. Andrew Garner, Ph.D., an associate clinical professor of pediatrics at Case Western Reserve and a fellow of the American Academy of Pediatrics.
Garner wrote an overview on the research in the group’s journal, Pediatrics.
Scientists are still debating how emotionally damaging experiences in childhood can have physical effects years later, but by now it’s pretty well established that they do.
Adverse events in childhood have been linked to many of the widespread, expensive chronic diseases that mar health outcomes in the United States.
These include asthma, obesity, type 2 diabetes, metabolic syndrome, cardiovascular disease, migraines, autoimmune conditions, and chronic pain and fatigue syndromes.
“It’s becoming more mainstream because there is now an abundance of evidence from studies of many different types that are showing the same patterns over and over again, that early adversity is a potent and powerful predictor of health outcomes later in life,” said Katie McLaughlin, Ph.D., a psychologist at the University of Washington in Seattle.
The question is how these findings will change how we prevent, diagnose, and treat disease and mental health issues.
Ghosts in the Machine
Looking at adverse events that include violence in the home, deaths in the family, and emotional neglect, the ACE studies found far more of these damaging events than anyone expected.
Two-thirds of the more than 15,000 study participants had at least one ACE; 1 in 8 had four or more ACEs. It’s with scores above four that the risks of disease become pronounced.
Nor were the study participants typically imagined as living in dangerous and chaotic circumstances. They were largely well educated and middle class. All were insured through Kaiser Permanente.
Certainly, poverty is an adverse experience. But adversity research shows it’s not the only one.
“We’ve got the material: health behaviors, damp houses. And we’ve got the immaterial — how people treat me and my physical response to how they treat me,” said Lucy Aphramor, Ph.D., a dietician who has helped pioneer the Health at Every Size movement.
That movement argues, in part, that pressuring high-body-mass patients to lose weight adds to their stress, potentially doing more harm than good.
In a sense, the exploration of how adversity gets “biologically embedded,” as Garner put it, fleshes out what researchers had already observed in population studies.
For instance, doctors have long known that obesity, asthma, and heart disease were more prevalent in lower-income communities. The link between a history of psychological trauma and chronic fatigue syndrome is also widely accepted.
“What we’re working on is beginning to understand how early experiences influence health later, building on previous research that suggests that these are associated. The question we’re focused on is why and how,” McLaughlin said.
Studies on adversity have done that thanks to advances in epigenetics — the part of our genetics that takes the range of possibilities laid out by genes and turns them into moment-by-moment physical responses — and molecular biology, which examines the body’s internal communication systems.
A map of asthma risk based on population research would put whole neighborhoods in the same risk category. Adversity offers an explanation for the variation of risk within that neighborhood — not just from block to block or house to house, but even from one sibling to another in the same house.
Imagine the human body as a computer that comes prepared to create its own operating system to suit the individual’s particular circumstances. If those circumstances are dire, the body constructs an operating system that’s more focused on getting through today and less focused on minimizing long-term wear and tear on the body.
Later in life, the stress may go away, but the operating system remains.
In a study published last week, McLaughlin found that children who were raised in institutional Romanian orphanages showed “blunted” hormonal responses to a range of stressful experiences at ages 10 to 12.
Previous research in animals has shown that chronic stress first causes a constant flood of stress hormones.
But the process then seems to exhaust itself. In McLaughlin’s study, the children who’d been moved to caring foster homes before age 2 returned to normal stress responses, but those who left the orphanages after age 2 did not.
Or take heart disease. It’s the granddaddy of all killers in the United States. Most Americans could rattle off the risk factors: high blood pressure, high cholesterol, excess body fat, etc.
But the contribution each of these makes to a person’s chance of developing heart disease is measured in single-digit numbers.
“That’s completely blown out of the water when you look at childhood adversity,” Garner said.
A Clue to the Obesity Epidemic?
Stress during key developmental periods can lock in dysfunctional responses. But constant stress later in life can also make the body unable to return to a healthy baseline.
A hectic work schedule won’t do it, though. It requires stresses that overwhelm the body’s natural ability to regulate itself. Researchers call this “toxic stress.”
Toxic stress has more recently emerged as a partial explanation for the rise of type 2 diabetes and other metabolic conditions.
“These models are all linking a certain aspect of the chronic stress response to metabolic syndrome,” said Alessandro Bartolomucci, Ph.D., an integrative biology and physiology professor at the University of Minnesota who studies mice that have lost the battle to be the dominant male in their cages.
When dominant and subordinate mice get the same food, the subordinate mice put on more fat. The subordinate mice, facing more stress, also develop insulin resistance when they’re fed a high-fat diet that approximates modern Western eating habits. Insulin resistance is a marker of pre-diabetes.
Aphramor sees stress as a factor in why some people develop pre-diabetes or other metabolic problems.
“These are things that are linked with what we generally blame on obesity,” she said. But “that pathway can happen independently of health behaviors.”
Lousy health lifestyle choices lead to high cholesterol and insulin resistance, and stress can cause poor choices. But the line of correlations between adversity and weight-related problems is actually stronger if we don’t consider lifestyle choices, Aphramor says.
Findings like Bartolomucci’s may make the case that healthcare providers should stop shaming patients for their weight and instead focus on getting them to care about other health benchmarks, such as blood glucose levels.
Being badgered about one’s weight, Aphramor says, is a source of stress not unlike the “subordination stress” Bartolomucci studies as the cause of metabolic problems in mice.
Healthline asked Bartolomucci what he thought of that view. “Clearly, there are components of a vicious cycle,” he said.
It may feel deeply pessimistic to imagine that kids who survive abuse and neglect will later die of lung cancer or heart disease as a result of their hardships.
But healthcare providers engaged with adversity research see this newer view of disease as potentially revolutionary. Cutting-edge science gives way to something akin to social justice advocacy.
“The model now is, ‘What’s wrong with you? How can I fix you?’” Garner explained. “When you start understanding ACE data, the question is ‘What happened to you?’ That’s a very different response. It triggers an empathetic response, and I would argue that’s the beginning of healing.”
Aphramor put it in very similar terms.
“It’s a whole different way of asking questions and also of being with people. The relationship I enter into is very, very different,” she said. “There’s not a hierarchy of oppression. I want to reach that place in myself and say, ‘I’ve had a hard time and that doesn’t stop me from lending a hand to someone else.’”
People can bounce back from hardships given the chance, Aphramor insists. She cites research on survivors of German concentration camps who went on to live happy, fulfilling lives.
“If people see the world as meaningful and manageable and think they’re a worthwhile human being and it’s worth making the effort, they can go on to flourish,” she said.
Garner would like to see doctors stop “chasing all these symptoms and unhealthy behaviors” and instead help direct patients toward better ways of dealing with stress.
“It’s easier to teach an alternative than to say stop: stop smoking, stop eating chips,” he said.
It’s not clear that these shifts can happen in the doctor’s office. But the explosion of chronic diseases, many linked with adverse events, suggests it may be worth a try.
Just saying “I feel sad” or “I feel angry” shifts the areas of the brain that show activity in an MRI machine, Garner said.
This idea has its roots in Buddhism, but it has received growing medical attention in the past decade. Just this week, a study published in the British medical journal The Lancet showed that mindfulness was as effective as medication in preventing relapses of major depression, which is strongly correlated with higher ACE scores.
Of course, the real fix for adversity-fueled conditions is to reduce the adversity kids face.
“We can do a better job of getting environment right the first time,” Garner said.