Poverty collides with health every day.
“Socioeconomic status is the most powerful predictor of
disease, disorder, injury and mortality we have,” says Tom Boyce, MD, chief of University
of California San Francisco’s Division of Developmental Medicine within the
Department of Pediatrics. Socioeconomic status is a term that often includes
measurements of income, education, and job prestige – individually or in
combination. The predictive power of income alone is perhaps most obvious when
considering life expectancy. Impoverished adults live seven to eight years less
than those who have incomes four or more times the federal poverty level, which
is $11,770 for a one-person household, whether you live in Silicon Valley, the
Rust Belt or the rural South.
Discrepancies in life span grow significantly when race
enters the equation. Paula Braveman, MD ’79, MPH, director of UCSF’s Center on
Social Disparities in Health, points to a recent life-expectancy study that
used education to reflect socio-economic status and that also considered race.
“They found that white people with more than 16 years of education lived 14.2
years longer than black people with less than 12 years of education,” says
Braveman, who has published extensively on social disparities for more than two
decades. “It’s shocking. It reflects the combined effects of socioeconomic
disadvantage and additional racial inequities.”
Poverty and its effects on mental and physical health are
the subtext of many of the year’s headlines, be they on stories about the Black
Lives Matter movement, about rising levels of violent crime or about efforts to
establish a living wage. An expansion of Medicaid and an increase in the
minimum wage were among the top recommendations of the Ferguson Commission
report, compiled by a panel of experts to help heal the Missouri town torn by
the fatal shooting of an unarmed black teen. The panel supported its
recommendations with a chilling statistic: The average life expectancy in the
mostly black Missouri suburb of Kinloch is more than three decades less than in
the mostly white suburb of Wildwood.
Boyce and his colleagues put electroencephalogram (EEG) caps
on 8- to 12-year-old kids from low-income and affluent families as they played
a game. The EEG caps tracked the kids’ brain activity while the game directed
them to select a unique stimulus from a group of similar-looking stimuli. The
researchers found fundamental differences in brain function. “The kids from
poor families had lower IQs and less effective executive functioning, which
takes place in the prefrontal part of the brain – things like working memory,
semantic fluency and cognitive flexibility, the capacity to readily switch
tasks,” reports Boyce. All are essential for academic achievement and advancement.
Boyce points to a recent study in Nature Neuroscience showing that the further
you go up the scale in parental education, the more folding – or cortical
surface area – is evident in a child’s brain. Cortical surface area sets humans
apart from other species; our brains fold inward to squeeze more surface area
into our skulls. The kids with the better-educated moms had literally more
brain in regions supporting language, reading, executive functions and spatial
skills. “These differences are the central nervous system underpinnings of
growing up in poverty,” says Boyce. “It is especially important to understand
that finding neurobiological differences among children from disadvantaged
communities does not imply that the differences are genetic in origin. Rather,
many or even most such socioeconomic disparities in brain structure and
function are the direct consequences of early rearing in impoverished, chaotic
and stressful conditions.”
Chronic disease – which accounts for 70 percent of deaths in
the US– is also deeply rooted in poverty. UCSF’s Center for Vulnerable
Populations (CVP) is devoted to helping populations at risk for poor health and
inadequate health care because of social vulnerabilities. Researchers at CVP
report that chronic conditions are striking minority communities earlier and
more often. Take diabetes: 10 years ago, one in 11 kids had prediabetes; now
it’s one in four. “If you look at minority populations, 50 percent of African
American and a third of Latino children will develop diabetes in their
lifetime. Those are staggering numbers, and if you look at the poor among them,
they are even more so,” says Kirsten Bibbins-Domingo, PhD ’94, MD ’99, director
of the CVP. “These diseases usually happen in middle age, but we are already
seeing real chronic disease manifestations in people in their 20s, teens, and
even younger.”
Diet and exercise play a big role in determining a person’s
health status; however, research shows that health behaviors like these are
largely driven by the context of where people live. Poor neighborhoods are more
likely to have higher crime rates, lower-performing schools, and little access
to healthy foods. “It’s difficult to exercise in an unsafe neighborhood, or to
eat well in a neighborhood where healthy foods are either not sold or are more
expensive than unhealthy options,” says Nancy Adler, PhD, director of UCSF’s
Center for Health and Community. Transportation and time also factor into
health behaviors. A person who has strung together three jobs to make ends meet
for his or her family, and who must travel by bus to each job, likely does not
have the luxury of time for exercise. Then imagine layering on top of poverty a
sick child. Take, for instance, a family with a child just diagnosed with
severe asthma – a chronic condition commonly found in children living in areas
exposed to high levels of automobile exhaust. “The mom may not have a job that
lets her leave to take care of her child. She has to deal with health
insurance, accessing specialists, and getting and affording medications,” says
Anda Kuo, MD ’98, a resident alumna, and the founding director of UCSF’s
Pediatric Leadership for the Underserved, a residency training program. “All of
that is incredibly stressful, and we know that, ultimately, impoverished
children with a chronic disease or cancer diagnosis face higher rates of
morbidity and mortality than others.”
In fact, the sheer stress and adversity of poverty itself is
perhaps its most toxic component, impacting multiple systems in the body. “We know
that kids growing up in poverty are more exposed to toxins, noise, turmoil and
violence,” says Boyce. “These exposures damage the capacity of the brain to
develop optimally.” They provoke the body to produce the hormone cortisol,
which sets the body on high alert so that people can maximize their capacity to
escape a threat. Put in evolutionary terms, this means that if you encounter a
lion, your body releases cortisol so you can get away.
“Cortisol basically shuts down functions you don’t need in a
moment of extreme stress, like reproduction or digestion. Your blood pressure
goes up, it mobilizes glucose, so you have energy for the escape,” says Adler.
That’s fine when you encounter a lion every once in a while. But when you
encounter stress every day at home or work, it takes a toll. People who have a
continually heightened response to stress can acquire an allostatic load – wear
and tear on the body caused by stress – that permanently throws off their
endocrine system and causes it to overproduce cortisol. Their cortisol level
goes up and doesn’t come down, putting them at lifelong risk of cardiovascular
disease. Others exposed to constant stress have a “hypo-response,” a flattening
effect, and they don’t produce cortisol even when it is needed, creating a
heightened risk for autoimmune diseases like arthritis, explains Adler.
“Poverty gets under our skin and leads to biological changes
that can last into adulthood, even when circumstances change, and, in some
cases, affect the next generation through maternal health,” says
Bibbins-Domingo. There is emerging evidence that the stresses of poverty could
create a lasting effect through what are called epigenetic changes in how our
genes are expressed, and that these effects may even happen in utero. “So,
cyclically, poverty leads to poor health and poor health leads to poverty,”
says Bibbins-Domingo, who holds the Lee Goldman, MD, Endowed Chair in Medicine.
“If that cycle happens across generations, then you are talking about major,
seemingly intractable effects on communities living in poverty.”
“I want to see the children of the Bay Area leading lives
determined by their own efforts and talents, not the incomes of their parents.
That is the essence of the American dream.” says Anda Kuo, MD, the founding
director of UCSF’s Pediatric Leadership for the Underserved.
According to Adler we must shift the focus of health care
away from how we treat disease to acknowledging why the disease happened in the
first place. “The analogy I like to use is this: If you are hit by a truck, you
are going to want to be treated at SFGH; it’s San Francisco’s only Level I
trauma center,” she says. “But, in the end, your health is going to be more
affected by the fact that you were hit by the truck than by how the health care
system managed your care. Poverty is that truck.”
How does a clinician prevent or treat disease in poor
patients if unstable housing, low-performing schools, and exposure to toxins
and violence conspire to undermine their health?
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U.S. Ranks Second to Last in Child Poverty |
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