Sustained Economic Hardship and Cognitive Function: The Coronary Artery Risk Development in Young Adults Study.
BACKGROUND
The relationship between low income and worse health outcomes is evident, yet its association with cognitive outcomes is less explored. Most studies have measured income at one time and none have examined how sustained exposure to low income influences cognition in a relatively young cohort. This study examined the effect of sustained poverty and perceived financial difficulty on cognitive function in midlife.


METHODS
Income data were collected six times between 1985 and 2010 for 3,383 adults from the Coronary Artery Risk Development in Young Adults prospective cohort study. Sustained poverty was defined by the percentage of time participants' household income was <200% of the federal poverty level-"never" in poverty, "0< to <1/3," "≥1/3 to <100%" or "all-time." In 2010, at a mean age of 50 years, participants underwent a cognitive battery. Data were analyzed in 2015.


RESULTS
In demographic-adjusted linear regression models, individuals with all-time poverty performed significantly worse than individuals never in poverty: 0.92 points worse on verbal memory (z-score, -0.28; 95% CI=-0.43, -0.13), 11.60 points worse on processing speed (z-score, -0.72; 95% CI=-0.85, -0.58), and 3.50 points worse on executive function (z-score, -0.32; 95% CI=-0.47, -0.17). Similar results were observed with perceived financial difficulty. Findings were robust when restricted to highly educated participants, suggesting little evidence for reverse causation.


CONCLUSIONS
Cumulative exposure to low income over 2 decades was strongly associated with worse cognitive function of a relatively young cohort. Poverty and perceived hardship may be important contributors to premature aging among disadvantaged populations.
Division of Epidemiology and Population Health Sciences, Department of Public Health Sciences, University of Miami, Miami, Florida. Electronic address: axz122@miami.edu.
Adina
A
Zeki Al Hazzouri
Division of Epidemiology and Population Health Sciences, Department of Public Health Sciences, University of Miami, Miami, Florida.
Tali
T
Elfassy
Kaiser Permanente Division of Research, Oakland, California.
Stephen
S
Sidney
Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota.
David
D
Jacobs
National Institute on Minority Health and Health Disparities, Bethesda, Maryland.
Eliseo J
EJ
Pérez Stable
Departments of Psychiatry, Neurology, and Epidemiology, University of California San Francisco, San Francisco, California;; San Francisco Veterans Affairs Medical Center, San Francisco, California.
Kristine
K
Yaffe
D003071:Cognition; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011203:Poverty / Q000523:psychology*
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