Neurodevelopment and the Health-Wealth Gap

 

By Danielle Gerhard

 

The famous Roman poet Virgil said that the greatest wealth is health. But what if your actual wealth affects your access to health?

 

It is estimated that more than 45 million Americans, or 14.5% of the population, live below the poverty line, according to the most recent Census Bureau survey. Although slightly lower than previous years, the poverty rate for children under 18 is still startlingly high: 19.9%. Poverty dictates how an individual lives their life and most importantly, what resources they have easy access to. Proper nutrition, environmental stimulation, basic healthcare, and family nurturing are all resources shown to aid healthy development yet are lacking in low-income communities.

 

An individual’s zip code is considered to be as much of a risk to one’s health as their genetics. Dr. Melody Goodman of Washington University in St. Louis researches the contribution of social risk factors to health disparities in local communities. One particular area in St. Louis, known as the Delmar Divide, is a stark example of how location is predictive of education and health. To the south of Delmar Boulevard is a largely white community with an average income of $47,000 and 67% of residents having a bachelor’s degree. Directly north of Delmar Boulevard is a predominantly African American community with a lower average income of $22,000 and only 5% of residents have a bachelor’s degree. In addition to income and education following the so-called Delmar Divide, health is also negatively affected. Higher rates of cancer, heart disease and obesity are only a few of the diseases plaguing these neglected, low-income neighborhoods.

 

Because our brains are rapidly developing during childhood, this leaves them more vulnerable to stress and environmental changes. Recently scientists have extended their efforts to better understand the long-lasting effects of income and environment on the brain and behavior. There have been a number of studies that look at the behavioral consequences of growing up in disadvantaged families, including increased risk for behavioral disorders, developmental delays, and learning disabilities. Fewer human studies have looked into the long-lasting effects of childhood poverty on brain regions known to be critical for executive function, attention and memory. Two studies published recently attempt to investigate this very question using a large-scale, longitudinal design in children between 3 and 20 years of age coming from different socioeconomic backgrounds.

 

One longitudinal, multi-site study published in JAMA Pediatrics investigated whether or not childhood poverty caused significant structural impairments in brain regions known to be important for academic performance. Key regions targeted in the study include the frontal lobes, involved in behavioral inhibition and emotion regulation, the temporal lobes, important for language and memory, and the hippocampus, a region shown to be critical for long-term memory as well as spatial and contextual memory. Demographic information and neuroimaging data was collected from nearly 400 economically diverse participants who were controlled for potential confounding factors such as health problems during or after pregnancy, complicated medical histories, familial history of psychiatric disorders, and behavioral deficits.

 

As hypothesized, children raised in low-income families had lower scores on the Wechsler Abbreviated Scale of Intelligence (WASI), which measures intelligence via verbal and performance IQ, and the Woodcock-Johnson III Tests of Achievement (WJ-III), a test for math skills and reading comprehension. Anatomically, children raised in low-income families showed reductions in gray matter (or volume – where most of the brain’s cells are housed), in the frontal and temporal lobes as well as in the hippocampus, with the largest deficits seen in children living well below the federal poverty line.

 

Another study recently published in Nature Neuroscience reported similar findings. The authors investigated whether poverty, defined by a parent’s education level and income, is predictive of neurodevelopmental deficits in key brain regions. As hypothesized, income is related to structural impairments in brain regions important for reading, language, and other executive skills. Similar to the study published in JAMA Pediatrics, this study found the strongest interaction in children from the poorest families.

 

These studies highlight the importance of access to beneficial resources during childhood and adolescence and how income and environment can drastically affect the trajectory of health and development of brain regions key to success into adulthood. A number of different programs for social change that are guided by empirical data and public policy are being implemented in disadvantaged communities. Sending healthcare workers out of the clinic and into these communities is a step in the right direction. However, some clinicians argue that this is unsustainable and instead advocate taking further steps towards training individuals who live in these communities and/or have healthcare providers move into these communities.

 

Furthermore, initiatives focusing on children and adolescents, in particular, could prevent more problems, possibly irreversible ones, from occurring down the road. Interventions directed towards reducing income inequality, improving nutrition, and increasing access to educational opportunities could drastically redirect a child’s trajectory into adulthood. Early education programs targeting children aged 3-5 years of age have been shown to improve future education attainment and earnings as well as reduce crime and adult poverty.

 

An unhealthy, broken social support system nurses an unhealthy, broken environment in disadvantaged regions lacking basic resources. Scientific knowledge can help direct public policy initiatives towards programs that could have greater impacts on society. A continued dialogue among scientists, politicians, and community activists is vital to the health not only of the children growing up in low-income communities but arguably to the health of our society as a whole. Solely placing funds and resources towards ameliorating adult poverty is akin to placing a band-aid on the problem. Today’s children are tomorrow’s adults, thus helping today’s children help’s tomorrow’s adults.