Education and physical activity mediate the relationship between ethnicity and cognitive function in late middle-aged adults

Objective. Minority status has been implicated as a risk factor for disparate scores on cognitive function tests in older adults. Research on ethnicity and cognitive function has yielded socioeconomic status, particularly education, as a primary reason for the discrepancy. Other factors, such as physical activity may provide insight into the relationship. Despite this knowledge, few studies have thoroughly examined the mediating characteristics of education or physical activity in the relationship between ethnicity and cognitive function in younger aged groups. Most research conducted focuses only on older adults during a time when degeneration of brain tissue may complicate the exploration of the relationships among ethnicity and cognitive function. The current research will expand existing knowledge about education, physical activity, and cognitive function in minority groups. Design. The study presents data from the Health and Retirement Study, a nationally representative sample of late middle-aged White, Black, and Hispanic adults (n=9204, mean age +/- SD = 55.8 +/- 3.1). Regression and mediation testing determined the mediating effects of education and physical activity in the relationship between ethnicity and cognitive function. Results. Significant association between White ethnicity and higher scores on cognitive tests was evident as early as late middle age. The magnitude of the association significantly diminished on adjusting for education and leisure time physical activity. Conclusion. Our data suggest a potential mediating role of education and physical activity on the ethnic differences in cognitive tests in late middle-aged White, Black, and Hispanic adults. Our findings suggest a need for studies to understand if adult education and culturally appropriate physical activity interventions in middle age influence ethnic disparities in prevalence of cognitive impairment in old age.