Young adults who experience periods of unsteady income are at risk of developing thinking problems and reductions in total brain volume later in life, reported authors of a recent study published in Neurology.
"Income volatility is at a record level since the early 1980s and there is growing evidence that it may have pervasive effects on health," said Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at Columbia Mailman School of Public Health, in a statement.
As part of the Coronary Artery Risk Development in Young Adults (CARDIA) study, Hazzouri et al. enrolled 3,287 participants who were 23 to 35 years old at the outset of the study. The subjects reported their annual pre-tax household income every three to five years for a total of 20 years, beginning in 1990.
Hazzouri and colleagues analyzed how often income dropped and the percentage of change in income per-patient during the study period. Participants were categorized into three groups: 1,780 who experienced no income drop; 1,108 who had one drop of 25% or more; and 399 who had two or more drops.
A total of 707 people received a brain MRI at the start of the study and then 20 years later to determine total brain volume along with other areas of the brain.
Those who experienced two or more fluctuations in income had smaller total brain volumes compared to participants with no income drops. Additionally, people with one or more drops had “reduced” connectivity in the brain.
Participants also completed thinking and memory tests, measuring how well they did and how quickly they were completed. In one test, for example, participants used a key that paired numbers with symbols; they were then given a list of numbers and asked to write down the associated symbols.
Results showed that those with two or more income drops performed 2.8% worse in the thinking and memory tests compared to those with no drops. Those with more drops also took longer to complete the tests.
"For reference, this poor performance is greater than what is normally seen due to one year in aging, which is equivalent to scoring worse by only 0.71 points on average or 0.53 percent," Hazzouri added.
The researchers speculated that those with an unstable income may have limited access to high quality healthcare, which may limit their ability to deal with diseases or unhealthy behaviors. Although the study doesn’t connect drops in income to reduced brain health, the authors noted, it does suggest more research is needed to understand how financial factors impact brain aging.