Financial health is closely related to physical health. Research has shown this, and that there are a variety of reasons why people in poor neighborhoods are not as healthy as those in wealthier areas. People in poor neighborhoods have less access to healthy foods compared to those who live in more affluent neighborhoods. They also tend to have fewer parks and outdoor spaces in which to exercise and decompress.

It's clear that living in poverty is not good for physical health, but what about mental functioning? There has not been much research on any possible impact, though a few studies have looked at the cumulative effect of socioeconomic hardship on cognitive function in the elderly.

But poverty makes younger people vulnerable, too, according to a new study. Young adults who grow up in poverty, and go on to experience financial hardship over the years, show reduced cognitive function.

“The overall size of [the] associations [we found] suggests that economic adversities experienced in young adulthood are important determinants of cognitive health in midlife,” the authors write.

Lead investigator, Adina Zeki Al Hazzouri, and her team collected income data six times from 3,383 adults over a 25-year period, from 1985 to 2010. In 2010, at a mean age of 50 years old, participants took three commonly used tests of cognitive function that are considered reliable measures of cognitive aging.

Young adults who grow up in poverty and go on to experience financial hardship over the years, show reduced cognitive function.

The researchers found a strong, incremental association between poverty and perceived financial hardship and poor performance on these tests. Those who had always lived in poverty performed significantly worse on tests of cognitive functioning than those who had never lived in poverty. The effect was more pronounced among African-Americans and women.

People are likely to experience income changes and mobility, especially between young adulthood and midlife, said Al Hazzouri, an assistant professor of public health at the University of Miami in Florida. So monitoring these changes over an extended time period may have significant implications for public health policy.

The study is published online in the American Journal of Preventive Medicine.