In one of the first studies to examine the effect of both socioeconomic status and neighborhoods on children's health, researchers at San Francisco State University and the University of California, San Francisco (UCSF) found that living in higher opportunity neighborhoods may protect children from some of the negative health impacts associated with growing up poor.

Children's health experts have long known that children from low-income families are more likely to experience lower birth weight, higher rates of injury, childhood obesity, chronic stress and poorer overall health. Researchers have also long known that broader environmental concerns -- such as polluted air -- can have negative health impacts, including diseases like asthma. But until recently, not as much has been known about the influence of neighborhoods.

"We know that income is one of the biggest social determinants of health and that it gets more impactful over the life span. So anything that can offset the negative effects of one's personal or family income -- besides raising your income -- is notable and important," said San Francisco State Assistant Professor of Psychology Melissa Hagan.

Hagan, UCSF lead author Danielle Roubinov and three other UCSF researchers studied 338 kindergarten-aged children from six public schools in the San Francisco Bay Area. They took saliva samples during the fall and spring to measure the children's levels of cortisol, a hormone associated with stress. They analyzed parent income and education to evaluate socioeconomic status and used the Childhood Opportunity Index (developed by Brandeis University and Ohio State University) to assess neighborhood quality and opportunities like green spaces, social services and schools.

In the fall, the researchers found that children from lower socioeconomic backgrounds living in neighborhoods with fewer opportunities had higher cortisol levels than children from neighborhoods with more opportunities. In the spring, they found that these same children were in poorer physical health -- as evaluated by teachers and parents -- than children who lived in higher opportunity neighborhoods, but their cortisol levels were not as high as in the fall. Hagan says that could be because many children experience higher stress levels at the beginning of the school year than at the end. Still, their cortisol levels were higher than in children from neighborhoods with more resources.

"What's most important is demonstrating the ways in which income and economic resources can act on health at different levels," said Hagan. "If children who are living in low-income families can be supported by being in a community that offers appropriate resources, it's pretty notable that their physical health can benefit."