Abstract and Introduction
Little research has investigated the long-term relationship between low wages and memory decline, despite the growing share of low-wage workers in the US labor market. Here, we examined whether cumulative exposure to low wages over 12 years in midlife is associated with memory decline in later life. Using 1992–2016 data from the Health and Retirement Study, we analyzed data from 2,879 individuals born in 1936–1941 using confounder-adjusted linear mixed-effects models. Low-wage work was defined as an hourly wage lower than two-thirds of the federal median wage for the corresponding year and was categorized into "never," "intermittent," and "sustained" based on wages earned from 1992 to 2004. Memory function was measured at each study visit from 2004 to 2016 via a memory composite score. The confounder-adjusted annual rate of memory decline among "never" low-wage earners was −0.12 standard units (95% confidence interval: −0.13, −0.10). Compared with this, memory decline among workers with sustained earning of low midlife wages was significantly faster (βtime×sustained = −0.014, 95% confidence interval: −0.02, −0.01), corresponding to an annual rate of −0.13 standard units for this group. Sustained low-wage earning in midlife was significantly associated with a downward trajectory of memory performance in older age. Enhancing social policies to protect low-wage workers may be especially beneficial for their cognitive health.
In the United States, 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—has slowed over time,[2–4] and the minimum wage has not kept up with inflation. Regularly earning low wages is potentially a public health problem, as lower socioeconomic status (SES) is a determinant of numerous adverse health outcomes.[7–10] However, limited literature has examined the relationship between low wages and health.[11,12]
Of particular concern is how low wages may affect cognitive health. Structural forces such as race- and sex-based discrimination and educational inequality drive certain groups of individuals into sustained low-wage employment, producing a low-wage workforce disproportionately composed of, for example, women, Black workers, and workers with low education; prior research has also documented inequalities in aging-related disorders among these groups.[14–18] However, whether sustained earning of low wages affects cognitive function is an open question. Low-wage jobs—particularly those also considered "low-skill"[19,20]—are often characterized by factors that may harm cognition, including toxic exposures,[21–23] injuries,[21,22,24] and work-related stress.[25,26] Low-wage jobs have been previously associated with health outcomes such as depressive symptoms, obesity, and hypertension,[29,30] which are risk factors for cognitive aging.[31–34] However, to our knowledge, no prior studies have examined the specific relationship between low wages during working years and later-life cognitive functioning.
To fill this gap, we estimated how low-wage employment history during the peak earning years in midlife affected subsequent longitudinal changes in memory function in older age among US adults in the Health and Retirement Study (HRS). We hypothesized that a prolonged history of low wages would be associated with faster memory decline in old age. Further, because women make up a disproportionate share of the low-wage workforce and have been shown to have a higher lifetime risk for cognitive disorders such as Alzheimer disease,[14–16] we explored whether the relationship varied by sex.
Am J Epidemiol. 2022;191(12):2051-2062. © 2022 Oxford University Press