How Childhood Trauma Can Cause Adult Obesity
The Mongolian Death Worm
By MAIA SZALAVITZ – Tue Jan 5, 4:20 am ET
Dr. Vincent Felitti, founder of Kaiser Permanente's Department of
Preventive Medicine and director of its obesity-treatment program, was
seeing some good results. His patients were losing 50, 80, even
hundreds of pounds. And he might even have considered the program a
success, if not for the fact that the participants who were doing the
best - those who were both most obese and losing the most weight -
kept dropping out.
Felitti was baffled. Why, invariably, did so many patients quit just
as they approached their healthy goal weight? Ella, for instance, a
middle-aged woman who entered the program in the mid-1980s morbidly
obese at 295 lbs., had managed to whittle her frame by 150 lbs. over
six months. "Instead of being happy, she was having anxiety attacks
and was terrified," Felitti says. (See "The Year in Health 2009.")
He asked Ella what she thought was going on. "Finally, the story comes
out," he says. "She had been molested as a child, both within her
family and outside it. She tried to escape by marrying at 15, at her
mother's urging. It was a disastrous marriage - her husband was crazy
jealous. They divorced in two years. She remarried. Her new husband
was also jealous. He was convinced that when she was out hanging the
laundry, she was sexually posturing to attract the neighbors."
When Ella was overweight, Felitti learned, her husband was less
suspicious. And her fear of his rage - perhaps he saw her new slimmer
weight as a provocation? - was probably spurring her anxiety. (See a
special report on the science of appetite.)
Felitti wondered if there was something similar barring weight loss in
other patients - or causing obesity itself. In the late '80s, he began
a systematic study of 286 obese people, and discovered that 50% had
been sexually abused as children. That rate is more than 50% higher
than the rate normally reported by women, and more than triple the
average rate in men. Indeed, the average rates of sexual abuse are
themselves unsettling: according to a large 2003 study conducted by
John Briere and Diana Elliott of the University of Southern
California, 14% of men and 32% of women said they were molested at
least once as children.
In recent years, studies by both Felitti and others have largely
confirmed the association between sexual abuse - as well as other
types of traumatic childhood experience - and eating disorders or
obesity. A 2007 study of more than 11,000 California women found that
those who had been abused as children were 27% more likely to be obese
as adults, compared with those who had not, after adjusting for other
factors. A 2009 study of more than 15,000 adolescents found that
sexual abuse in childhood raised the risk of obesity 66% in males in
adulthood. That study found no such effect in women, but did find a
higher risk of eating disorders in sexually abused girls.
Discoveries by Felitti and colleagues have also helped give rise to
broader work linking stressful experiences early in life - as early as
in the womb - to effects on health and behavior later on, such as an
increased risk of heart disease or becoming addicted to drugs.
Scientists are finding that such effects are not only long-lasting,
but can even be inherited by future generations. (Watch a video about
obesity and social networks.)
In decades of experiments with rats, for instance, neuroscientist
Michael Meaney at McGill University in Canada and his colleagues have
shown how such environmentally induced traits can be passed down -
then undone, also by environment. Meaney studied rats with differing
maternal styles - some were naturally nurturing (they licked and
groomed their pups constantly), others were less attentive and even
neglectful (mother rats placed in stressful environments like
isolation had greatly decreased capacity for nurture). What
researchers found was that these behavioral traits were passed down to
future generations: pups born to neglectful mothers endured stressful
childhoods and grew up to become neglectful mothers themselves. But
when babies born to stressed or less attentive mothers were instead
placed with nurturing, affectionate mothers, that early experience
changed the pups. They adapted quickly to the new mothering style and
grew up to tend carefully to their own offspring. These pups'
adaptation was then passed to successive generations as well.
When Felitti first presented his Kaiser Permanente data connecting
obesity with child molestation at a national meeting on obesity in
1990, most colleagues dismissed him immediately (one even claimed that
obese people made up such stories to justify their "failed lives").
David Williamson, an epidemiologist at the Centers for Disease Control
and Prevention (CDC), was the lone exception. He said that a large
epidemiological study was needed to determine whether there were any
implications of Felitti's findings for public health.
Felitti knew that he had just the right data set: Kaiser Permanente
has the largest medical-evaluation facility in the developed world,
diagnosing some 58,000 patients annually. Even if only a minority
agreed to discuss their childhoods and allow anonymous use of their
medical records, that would be a huge sample. And so the Adverse
Childhood Experiences (ACE) study was born, as a collaboration of
Felitti and another CDC researcher, Dr. Robert Anda.
For the past several decades, the ACE study has recorded reports of
negative childhood experiences in more than 17,000 patients. Adverse
experiences include ongoing child neglect, living with one or no
biological parent, having a mentally ill, incarcerated or drug-
addicted parent, witnessing domestic violence, and sexual, physical or
emotional abuse. The researchers then searched for correlations
between these experiences and adult health and the risk of disease.
The connections became clear: compared with a person with no adverse
childhood experiences, or ACEs, a person with four or more has almost
double the risk of obesity. Having four or more ACEs more than doubles
the risk of heart attack and stroke, and nearly quadruples the risk of
emphysema. The risk for depression is more than quadrupled. Although
many of these outcomes could reflect the influences of genes and other
environmental influences - beyond those occurring in childhood - the
tight relationship between increasing ACE numbers and increasing
health risks makes the role of child trauma clear. Dr. Jack Shonkoff,
director of Harvard's Center on the Developing Child, calls the
research "a tremendous contribution."
But how does the psychological experience of childhood neglect cause
physical effects like obesity, heart attack or stroke? There are at
least two interconnected pathways - one physiological, the other
psychological.
The psychology is relatively straightforward: being abused or
otherwise traumatized is painful, and food can be a numbing or
comforting escape. Hence, abused children may turn to overeating,
which causes obesity. Indeed, ACEs are also strongly linked with other
types of unhealthy "self-medication": for instance, cigarette smoking
(which accounts for the increased rate of emphysema among high ACE
scorers) and drug abuse (having four or more ACEs increases the risk
of injectable-drug use by a factor of 10). As Felitti puts it, "Being
fat [or having other unhealthy behaviors] is not the problem. It's the
solution."
The psychological effects often exacerbate health problems that the
physiological stress response has already caused. High ACE scorers who
do not overeat, smoke or take drugs still have high rates of obesity,
heart disease, depression and diabetes. The mechanism for these risks
appears to lie in the biology of the stress-response system and in the
way environment affects a person's genetic activity.
For most of human evolution, a stressful world would have been marked
by famines or periods of starvation, and that environment might have
resulted in a particular pattern of gene expression that would have
prompted the body to store more fat in preparation for the next bout
of scarcity. Today, of course, the same response to stress would
result in obesity. This theory of a thrifty fat-storing system that
kicks in under high levels of early stress was originally proposed by
British physician David Barker.
If, for instance, a modern child's early life experience - in the womb
and during the first five years, particularly - is constantly
stressful, it would be incredibly energy-consuming, says Dr. Bruce
Perry, senior fellow at the ChildTrauma Academy. "If your genes get
the message that you are entering a stressful world, it makes complete
adaptive sense to take the existing metabolism and tune it up to
deposit fat and store energy to prepare for what the body is expecting
will be a challenging and stressful life," he says.
"Early adverse experience can disrupt the body's metabolic systems,"
says Shonkoff. "One of the cornerstones of biology is that our body's
systems when they are young are reading the environment and
establishing patterns to be maximally adaptive."
Researchers also posit that high levels of stress hormones caused by
ACEs can wear down the body over time. A temporary spike in blood
pressure in response to a stressful event may be useful to power an
adaptive fight-or-flight response, but over the long term constant
high blood pressure could raise a person's risk for heart attack and
stroke. Studies have also found that consistently elevated levels of
stress hormones, like cortisol, can lead to permanent damage in
certain brain regions linked to depression.
Recently, scientists have discovered that these changes can themselves
be passed down from one generation to the next - a burgeoning new area
of study called epigenetics. Such research may have significant and
long-term implications for the prevention of obesity, addiction and
other illnesses related to early life stress. After all, reducing
childhood exposure to trauma in one generation may further benefit
that generation's children and grandchildren.
Some initiatives, such as the nurse home-visiting program and
President Obama's proposed Promise Neighborhoods program, already put
this theory into practice, by offering support and services to low-
income parents in order to reduce child abuse, increase access to
prenatal care and provide parenting education and high-quality day
care.
The goal is not only to improve conditions for the current
participants of such programs, but also hopefully to reduce the risk
of problems in successive generations, including major causes of death
and disability like obesity, heart disease and stroke. "It's not a
secret that there is a growing epidemic of obesity and there's no
question that the way we eat and the way we exercise, or do not
exercise, is contributing to it. But it's a huge mistake to attribute
it just to the need to close down fast-food restaurants and turn off
the TV. There's important biology here early in life that needs
attention," says Shonkoff.
- Szalavitz is co-author, with Dr. Bruce Perry, of the forthcoming
Born for Love: Why Empathy Is Essential and Endangered