by Jo Marchant
As if all this wasn’t enough, there is one more problem that stress can cause, arguably the worst of all. In 2004, Elissa Epel and Elizabeth Blackburn at the University of California, San Francisco, measured the effects of stress on repeating DNA motifs on the end of chromosomes, called telomeres, which play a crucial role in the aging process.17 These caps shield the ends of our chromosomes each time the DNA is copied and our cells divide. But they are worn down themselves in the process. When telomeres get too short, cells malfunction and lose their ability to divide, meaning that our tissues are no longer able to renew themselves.
Epel and Blackburn studied telomeres in two groups of mothers: one with healthy children and one that, like Lisa, had children with chronic conditions such as autism. It turned out that the more stressed the women felt, the shorter their telomeres were.18 The most frazzled women had telomeres that looked ten years older than those of the women who felt least stressed, and their levels of telomerase, an enzyme that rebuilds telomeres, were halved. In other words, the researchers claimed, feeling stressed doesn’t just make us ill. It ages us.
The study was described by stress researcher Robert Sapolsky as “a leap across a vast interdisciplinary canyon,”19 connecting the women’s complex lives and experiences to the molecules inside their cells. Many telomere experts were skeptical at first but Epel and Blackburn’s paper sparked a burst of research, and stress has now been linked to shorter telomeres in many different groups, including older women; Alzheimer’s caregivers; victims of domestic abuse, rape and early life trauma; and people with psychiatric disorders such as depression and PTSD.20
“Ten years on, there’s no question in my mind that the environment has some consequence on telomere length,” says Mary Armanios, who studies telomere disorders at Johns Hopkins School of Medicine in Baltimore, Maryland.21
People with shorter telomeres are more likely to have stress-related conditions such as diabetes, heart disease, Alzheimer’s and stroke, and they die younger.22 The big question for researchers now is whether short telomeres directly contribute to illness and mortality, or are just a harmless side effect of age-related damage. Seriously damaged telomeres clearly devastate health: people with the genetic disorders studied by Armanios, who have much shorter telomeres than normal, suffer from accelerated aging and organ failure.23 But she questions whether the smaller changes caused by stress will turn out to be significant, especially because telomere length is quite variable in the first place.
Blackburn, on the other hand, says she’s increasingly convinced that psychological factors are important. Genetic mutations that shorten telomeres to a lesser extent than the extreme cases studied by Armanios still increase future risk of a range of chronic conditions, she points out.24 And variations in telomere length equivalent to those caused by stress seem to predict future health even after taking into account traditional risk factors such as body mass index or blood sugar levels.25
The link with aging comes as no surprise to Lisa. Four years on from her son’s autism diagnosis, I ask whether her stress has had a physical impact. Yes, she says. She’s 42, with hair that’s naturally light brown, like Brandon’s. “But all of a sudden, over the past three years, my hair has turned gray.”
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I DRIVE east and then south from Atlanta, Georgia, until the city is long gone and the sun slants through the pine trees, making zebra stripes across the asphalt. Tom Petty is on the radio and birds of prey hover above, eyeing up the abundant roadkill.
After a couple of hours I reach the outskirts of a town called Milledgeville. The roads disintegrate into narrow lanes with rough edges, and the whole place feels forgotten. There are battered wooden homes behind wire fences, and some trailers with plastic chairs out front. At one point, my car’s navigation system directs me down a dead end; the asphalt falls into gravel that dissipates among the trees, in front of a stained white house with tiny windows and wooden legs.
Milledgeville is located in a crescent-shaped strip of land across the southeastern U.S. that’s informally known as the “black belt.” In the nineteenth century, this name was inspired by the color of the region’s unusually fertile soil, which was home to cotton plantations worked by slaves. It later came to refer to the high proportion of African Americans who live here, typically above 50% of the population.
Many people here now suffer debilitating poverty. The black belt is just 300 miles long by 25 miles wide, yet it is home to around a third of the nation’s poor. The region is characterized by substandard housing, schools and transport, as well as high crime and unemployment, all problems that disproportionately affect African American residents.26
And according to Gene Brody, a psychologist at the University of Georgia who studies the health of black belt families, these families have some of the highest levels of chronic disease in the country, including heart disease, diabetes, stroke and cancer. Stress, it turns out, doesn’t just affect individuals. In places like Milledgeville, it blights the health of entire populations.27
I’m interested to know what life is like here, so Brody has put me in touch with some of the residents, including Susan. When I eventually reach her home, I find a sturdy brick bungalow—the nicest house on the street—with brick steps leading up to the front, and a brick patio at the back. Bluebirds and red cardinals flash past. A sprawling yard, home to a battered pickup truck and piles more bricks, backs straight into the woods. Coyotes are regular visitors here, Susan tells me later, along with foxes, rabbits and wild turkeys.
She opens the door with an excited white dog in her arms. “We’re in the middle of a house clear,” she apologizes, as she ushers me past a cluttered hall into an immaculate living room. On one wall is a huge ornate mirror, on another, two miniature gold violins. There’s a fluffy turquoise rug and cushions with long fringes, while the shelves are filled with family photos and cut glass.
Susan has short, gray hair and no makeup, and is casually dressed in bright pink jogging bottoms and a baggy Georgia College Bobcats T-shirt. When she greets me, her voice is strong and resonant.
She was brought up in Milledgeville, she says, in a “shotgun house”— so called because you could stand and look straight through—with an outdoor toilet, and two outdoor water taps shared between nine families. “We had a huge black pot to warm the water,” she recalls. They made their own soap, and hog head cheese from fragments of pork. She lived with her grandparents. (“I knew who my parents were,” she says. “But they were just somebody I knew.”) Her grandfather spoiled her, but her grandmother kept her in line with a switch. Lots of her friends missed school to pick cotton—Susan wanted to but her grandmother wouldn’t let her. “She said it eats all the skin from around your nails, and ruins your hands.”
Susan is now a central member of this community; she’s active in the church, and volunteers at a local children’s center. She has been married to her husband, George, for 50 years. It’s clear they have fought hard for what they have. George built this house himself, she says, using bricks scavenged from other houses that were being demolished. She points out the huge fireplace, made of bricks from her childhood home.
When I ask what life in Milledgeville is like today, she tells me that unemployment is a huge problem. The farm jobs are long gone, and she has seen most of the area’s big employers disappear too: Mohawk, which makes carpet fibers; manufacturing company JP Stevens; Oconee Brick. Young people here, she says, have largely given up. “They’re not prepared to go to college,” she says. “All they want is easy money.” Instead, the area “is corrupted with drugs.”
The challenges of life here show up in official statistics. More than half of African American children in the rural South live in poverty, and most of these grow up in single parent households. Life on a low income can be even harder here than in inner city neighborhoods, says Brody: it’s impossible to get around without a car, there are no jobs, and there’s nothing for young people to do. Youth drinking (and its consequences,
such as failure at school, bad behavior and risky sex) are rising faster in rural areas than in cities, with rural black teens now drinking as much as or more than their urban peers.28
Susan has four children, all now grown. She aimed to instill Christian values in them, she says, along with respect for their elders. But that wasn’t enough to save her daughter, Jennifer, from the lure of drugs and crime. Susan recalls chatting to a neighbor on the phone one day when the operator cut in and told her to go immediately to the police department’s public safety building. Jennifer’s 16-month-old daughter, Jessica, had just been rescued from a house where she and another child of similar age had been left alone for the entire day—completely ignored by three men who were apparently out on the porch.
Jennifer, it turned out, was in another county, in jail. More than 20 years later, Susan still remembers walking in and seeing her granddaughter and the other child sitting on the floor, with food on Styrofoam plates between their legs. She and her husband took Jessica in that day. They were already looking after her older brother, Kevin, and eventually cared for Jennifer’s third child too.
Jennifer has caused her lots of stress over the years, says Susan, like when she’d turn up demanding the kids. One time she disappeared with Kevin for several days; Susan and her husband were worried sick until they finally tracked them down in a motel. Now that the grandchildren have left home, though, she rarely sees her daughter. “What do we need her for now? They’ve grown.”
But Kevin still causes her heartache. After a brief spell in the military he left the army, came back to Milledgeville and got in with a bad crowd. A few weeks before my visit, he got out of jail and turned up at home, Susan says, wanting to move in. She told him to leave: “I can’t live with people who are going to steal from me.”
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SUSAN FELT so ill after the confrontation with her grandson that she went to the doctor, who put her on medication for high blood pressure. Indeed, living in this type of neighborhood—characterized by high crime, drug use, single parenthood, no job opportunities—can have dire consequences for health across the life span. Children in low-income families are more likely to be born small, to be born early and to die shortly after birth. As they grow up they have more health problems, including obesity, insulin resistance and asthma. Later in life, they are more likely to be ill and to die from stroke, cardiovascular disease, chronic lung disease and some cancers.29
The difference in health between rich and poor varies in different countries, roughly correlating with the level of economic inequality in that country.30 According to Greg Miller, a psychologist from Northwestern University in Evanston, Illinois, who studies the effects of poverty on health, it’s much more dramatic in the U.S. than in Canada or Sweden, for example, with Britain somewhere in between. “But disparities in health are persistent across almost all countries we know of, regardless of whether they are modern, industrialized countries or developing countries,” says Miller. “You see them within countries, you see them between countries, you see them in women and in men, within different ethnic groups, and at every stage of the life span all the way from pregnancy outcomes to dementia and stroke.”31
What causes the difference? The effect isn’t explained by access to health care or material resources; if this were the whole story, everyone above a certain threshold of basic need should have similar health. Instead, there’s a linear health gradient through the entire socioeconomic spectrum, right up to the most privileged groups. And although people living in poverty tend to lead unhealthier lifestyles (for example, drinking and smoking more and exercising less), when researchers account for this, the effects on health don’t disappear. In addition to behavioral factors, argues Miller, the stress and alienation of being poor cause chronic inflammation that damages health throughout people’s lives.
In particular, the environment we are exposed to as children seems to influence our susceptibility to stress later on. For example, some children from poor families work hard, go to college and leave for good jobs elsewhere, where they lead lifestyles just like those of their more privileged peers. They have low rates of drug use and behavioral problems, and appear to be perfectly healthy, says Brody. “But if you unzip the exterior and look at their biology, they look different.” They have higher blood pressure, and higher levels of circulatory stress hormones and inflammation.32
Regardless of their current circumstances, those who grow up in adverse environments also have increased rates of cancer, heart disease, illness and death from all causes. One study followed more than 12,000 Danish adoptees and found that mortality in their forties depended on the social class of their biological father, but not their adoptive father.33 Another tracked medical students enrolled at Johns Hopkins University, for 40 years.34 Among these educated, well-off doctors, those who had grown up in poor families were more than twice as likely to suffer from heart disease by the time they were 50.
Stress from adversity and inequality also seems to be a major force eroding telomeres. People who didn’t finish high school or are in an abusive relationship have shorter telomeres, for example, while studies have also shown links between short telomeres and low socioeconomic status, shift work, dangerous neighborhoods and environmental pollution.35 In African Americans, experiences of racial discrimination have been associated with various biological markers of stress, including shorter telomeres.36
Again, children are particularly at risk. Being abused or experiencing adversity early on—including in the womb, through exposure to a mother’s stress hormones—leaves people with shorter telomeres for the rest of their lives.
Results like this are leading some scientists to argue that to tackle the rising epidemic of chronic disease, governments need to reduce social inequality and in particular to support women of childbearing age. In 2012, Elizabeth Blackburn and Elissa Epel wrote a commentary in the prestigious science journal Nature, calling on politicians to prioritize “societal stress reduction.”37 The stress that women experience during pregnancy and while raising their children causes health problems and economic costs in the next generation for decades to come, they pointed out, even if those children later escape to more comfortable circumstances.
There’s now compelling evidence that the biology of how we age is shaped early in life, Epel tells me. “If we ignore that, and we just keep trying to put Band-Aids on later, we’re never going to get at prevention and we’re only going to fail at cure.”38
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TACKLING SOCIAL inequality is hardly a new idea, yet the sheer scale of the health problems caused by stress and poverty—and the finding that the circumstances we grow up in shape our disease risk for life—arguably provides a stronger case than ever for governments to act. But perhaps politicians still aren’t ready to leap across the interdisciplinary canyon that Blackburn and Epel bridged a decade ago. According to Epel, there was little response to the Nature article. “It’s a strong statement, so I would have thought that people would have criticized it or supported it,” she says. “Either way!”39
There are some efforts to put her vision into practice, however, and in chapter ten we’ll look at what happens when researchers try to buffer the effects of stress in some of the communities that need it most, including Milledgeville. But in the meantime, is there anything we can do as individuals to protect ourselves from the debilitating effects of stress?
Few of us can remove all the stress from our lives, any more than Susan can change her neighborhood or Lisa can hand Brandon back. But there is some good news. External problems—debt, rocky relationships, having a child with autism—do not generally damage our bodies directly. What harms us is our psychological response to those circumstances; not the state of our environment, but of our mind. And that is something we can control.
Wendy Mendes, a psychologist at the University of California, San Francisco, uses the example of a skier who unexpectedly comes across a steep, icy trail; it’s her only way down the mountain. The ski
er’s heart rate will likely rise as her body prepares for the descent. But depending on how experienced she is and whether she believes she has the skills to cope, her predominant emotion could be either fear or exhilaration.40
These contrasting mental states are both versions of fight or flight, but they have very different physical effects on the body, says Mendes.41 Both scenarios trigger the sympathetic nervous system (SNS), but excitement or exhilaration activates it to a greater extent. From an evolutionary point of view, this is the mindset of a hunter closing in for the kill; a runner being chased but confident of escape; a fighter who knows he has the upper hand. Our peripheral blood vessels dilate and our heart works more efficiently, pumping oxygenated blood to the limbs and brain. People experiencing this type of response perform better than normal, not just physically but mentally too.
Fear, on the other hand, causes the body to go into damage-control mode as it prepares for defeat. We’re being hunted and there is no escape. We’re in a fight against a stronger adversary. The SNS is activated but to a lesser extent. Our peripheral blood vessels constrict and our heart beats less efficiently, so less blood is being pumped around the body. This serves to minimize blood loss if we are caught and injured. But it impairs our performance and strains the cardiovascular system, because the heart is forced to work harder to push blood around the body. In addition, there’s a surge of the stress hormone cortisol, as the immune system prepares for injury and infection.
Psychologists call these contrasting responses “challenge” and “threat.” When we face stressful situations in modern life—public speaking, a confrontation with someone we’d rather avoid, or a physical challenge such as a ski trail—the same ancient calculation comes into play. We subconsciously weigh our chances: deep down, do we think we are going to win or lose? The answer is generally a combination of factors, say Mendes. Have you studied for the test? Are you an optimistic person? Did you sleep well last night? “All those factors can influence how we perceive our resources to cope with the task at hand.”
