Persistent low wages linked to faster memory decline in later life

Sustained low wages are associated with significantly faster memory decline, according to a new study by Columbia University Mailman School of Public Health. While low-wage jobs have been associated with health outcomes such as depressive symptoms, obesity, and hypertension, which are risk factors for cognitive aging, until now no prior studies had examined the specific relationship between low wages during working years and later-life cognitive functioning.

The findings are published in the American Journal of Epidemiology and were reported today at the 2022 Alzheimer's Association International Conference® (AAIC®) 2022 Promoting Diverse Perspectives: Addressing Health Disparities Related to Alzheimer's and All Dementias.

"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 Katrina Kezios, PhD, postdoctoral researcher in the Department of Epidemiology at Columbia University Mailman School of Public Health and first author. "This association was observed in our primary sample as well as in a validation cohort."

Research into the effects of lower income on health is rapidly expanding. Using records from the national Health and Retirement Study (HRS) of adults for the years 1992-2016, the researchers analyzed data from 2,879 individuals born between 1936 and 1941. Low-wage was defined as hourly wage lower than two-thirds of the federal median wage for the corresponding year.

Kezios and colleagues categorized study participants' history of low wages into those who never earned low wages, intermittently earned low wages, or always earned low wages based on wages earned from 1992 to 2004 and then examined the relationship with memory decline over the next 12 years from 2004-2016.

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 excess year of cognitive aging per a 10-year period; in other words, the level of cognitive aging experienced over a 10-year period by sustained low-wage earners would be what those who never earned low wages experienced in 11 years.

In the U.S., the federal minimum wage has remained $7.25 per hour since 2009. While economic growth has increased since then, 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.

"Increasing the federal minimum wage, for example to $15 per hour, remains a gridlock issue in Congress, "said Kezios.

"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 and the Columbia Butler Aging Center.

"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."

Reference:

Katrina L. Kezios, PhD; Adina Zhang, MS; Soohyun Kim, PhD; Peiyi Lu, PhD; M. Maria Glymour, PhD; Tali Elfassy, PhD; and Adina Zeki Al Hazzouri, PhD.