Data Tie Stress of Poverty to Brain

Children raised in poverty suffer many ill effects: They often have health problems and tend to struggle in school, which can create a cycle of poverty across generations. Now, research is providing what could be clues to explain how childhood poverty translates into dimmer chances of success: chronic stress from growing up poor appears to have a direct impact on the brain, leaving children with impairment in at least one key area - working memory.

"There's been lots of evidence that low-income families are under tremendous amounts of stress, and we know that stress has many implications," said Gary Evans, a professor of human ecology at Cornell University in Ithaca, N.Y., who led the research. "What this data raises is the possibility that it's also related to cognitive development."

Previous research into the possible causes of the achievement gap between poor and well-off children has focused on genetic factors that influence intelligence, on environmental exposure to toxins such as lead, and on the idea that disadvantaged children tend to grow up with less intellectual stimulation.

But Evans, who has been gathering detailed data about 195 children from households above and below the poverty line for 14 years, decided to examine whether chronic stress might also be playing a role. "We know low-socioeconomic-status families are under a lot of stress - all kinds of stress. When you are poor, when it rains it pours. You may have housing problems. You may have more conflict in the family. There's a lot more pressure in paying the bills. You'll probably end up moving more often. There's a lot more demands on low-income families. We know that produces stress in families, including on the children," Evans said.

For the new study, Evans and a colleague rated the level of stress each child experienced using a scale known as "allostatic load." The score was based on the results of tests the children were given when they were ages 9 and 13 to measure their levels of the stress hormones cortisol, epinephrine and norepinephrine, as well as their blood pressure and body mass index. "These are all physiological indicators of stress," said Evans, whose findings were published online by the Proceedings of the National Academy of Sciences.

When the researchers analyzed the relationships among how long the children lived in poverty, their allostatic load, and their later working memory, they found a clear relationship: The longer they lived in poverty, the higher their allostatic load and the lower they tended to score on working-memory tests.

-From “ Data tie stress of poverty to brain”, By Rob Stein, Washington Post, April 7, 2009, http://www.boston.com/news/health/articles/2009/04/07/data_tie_stress_of_poverty_to_brain/ retrieved 4/7/09.

 

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