Thursday, January 07, 2016

Poverty Becomes Disease

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?

U.S. Ranks Second to Last in Child Poverty