NEW YORK: Young adults who do not earn the same amount of money from year to year, or who weather substantial pay cuts, do worse on brain health assessments in midlife compared to those with steady income, a recent study suggests.
Researchers collected income data over two decades for 3,287 adults, starting in 1990 when they were 23 to 35 years old. They assessed income volatility based on how much earnings rose or fell from one year to the next, and also tallied how many times participants' income dropped by at least 25 per cent.
People who experienced greater income volatility and more pay cuts had worse scores for processing speed and executive functioning in cognitive tests in 2010. Brain scans that year also showed reduced connective white matter and worse structural integrity for people who experienced more income volatility and pay cuts.
"Overall, income volatility and unfavorable socioeconomic conditions may increase exposure to several risk factors of poor brain health," said Adina Zeki Al Hazzouri, a researcher at the Mailman School of Public Health at Columbia University in New York City.
"Individuals who experience important income fluctuations may be more at risk for cardiovascular risk factors, depression or perceived stress, which are in turn associated with poor cognitive health," Zeki Al Hazzouri said by email. "In addition, they may have lower access to high-quality healthcare, which may result in worse management of these risk factors, and potentiate their impact on brain health."
Changes in cognitive test scores and brain scans did not appear to differ when researchers only looked at participants with the most education.
Almost half of the participants, 1,780 people, didn't have any income drops of 25 per cent or more during the study period. People in this group had average annual income of US$39,681.
Another 1,108 people experienced one major income decline during the study period, and this group had average annual income of US$32,253. And 399 individuals with average annual income of US$33,326 experienced two or more substantial income reductions.
Having multiple income drops appeared worse for brain health than having a single large drop during the study period.
The study wasn't designed to prove whether earnings volatility directly impacts brain health.
However, economic struggles have been associated with unhealthy habits like smoking, drinking and inactivity that could in turn contribute to worse brain health, poor cognitive function and dementia, the study team writes in Neurology.
"It's well established that lower socioeconomic status is linked with poorer health," said Dr. Joel Salinas, an associate professor of neurology at Harvard Medical School and Massachusetts General Hospital in Boston who wrote an editorial accompanying the study.
"Factors like income volatility are especially significant when a recession looms," Salinas said by email. "Times of individual and societal instability can have tremendous and enduring consequences - far beyond the economic, extending into the long term potential for entire communities to thrive."