A lack of access to healthcare, nutritious food, and safe places to exercise all contribute to healthcare inequities. In the United States, people living in lower-income households have an increased risk for developing many chronic health conditions, including heart disease, diabetes, and obesity. But can earning less money, year after year, take a different kind of toll, and negatively affect our brains and memory? Unfortunately, that answer may be yes, according to new research presented at the Alzheimer’s Association 2022 Addressing Health Disparities conference.
Researchers from Columbia University found a link between a below-average paycheck and cognitive function down the road. “Our research provides new evidence that sustained exposure to low wages during peak earning years is associated with accelerated memory decline later in life,” said first author Katrina Kezios, PhD, postdoctoral researcher at Columbia Mailman School of Public Health in New York City, in a release.
Earning a Lower Wage Linked to Faster Memory Decline
Researchers used data gathered from 1992–2016 from 2,879 individuals enrolled in the Health and Retirement Study, a longitudinal survey of nationally representative samples of Americans aged 50 years and older.
Low-wage was defined as hourly wage lower than two-thirds of the federal median wage for the corresponding year. Researchers focused on participants’ earnings between 1992 to 2004, which were considered “peak earning years.” Subjects were placed into one of three categories: those who never earned low wages, people who intermittently earned low wages, or those who always earned low wages.
Study participants were interviewed every two years and provided, among other things, information on work-related factors, including hourly wages. Memory function was measured at each visit over a 12-year period from 2004 to 2016 using a memory composite score, which included immediate and delayed word recall memory assessments. On average, participants completed 4.8 memory assessments over the course of the study.
The researchers found that, compared with workers never earning low wages, sustained low-wage earners experienced significantly faster memory decline in older age. They experienced approximately one “extra” year of cognitive aging per a 10-year period; in other words, the level of cognitive aging experienced over a 10-year period by people who always earned a low-wage would be what those who never earned low wages experienced in 11 years.
“This association was observed in our primary sample as well as in a validation cohort,” says Dr. Kezios. A validation cohort is a separate group within the study that undergoes the same analysis. If the results are confirmed in the validation cohort, it strengthens the findings of the research.
The findings held true when researchers adjusted for several factors including age, sex, race or ethnicity, education, place of birth, marital status, parental education, lower skilled occupations, household wealth in 1992, and retirement status at first memory assessment.
More Than 1 in 10 Americans Live Below the Poverty Threshold
While economic growth has increased since the period when the study data was collected, wage and salary growth for employees — particularly those in low-wage jobs — have slowed over time, and the minimum wage has not kept up with inflation, according to the authors. In the United States, the federal minimum wage has remained $7.25 per hour since 2009.
One gauge of how many people are struggling to afford the basic necessities, the poverty threshold, indicates that the situation has worsened in the last few years. In 2020, the poverty threshold for an individual was $12,760; for a family of four, it was $26,200. The number of people living below this threshold rose significantly from 2019 to 2020, from 33.9 million to 37.2 million Americans (11.4 percent), according to the U.S. Census.
“Our findings suggest that social policies that enhance the financial well-being of low-wage workers may be especially beneficial for cognitive health,” said senior author Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at Columbia Mailman School in New York City, in the release. “Future work should rigorously examine the number of dementia cases and excess years of cognitive aging that could be prevented under different hypothetical scenarios that would increase the minimum hourly wage.”