The relation of education and income to cognitive function among professional women

We investigated the relation of educational attainment and annual household income to cognitive function and cognitive decline in community-dwelling women aged 66 years or older. Subjects were 6,314 health professionals participating in the Women's Health Study, among whom information on education and income was self-reported. From 1998 to 2000, we administered five cognitive tests, measuring general cognition, episodic memory and verbal fluency, using a validated telephone interview. Second cognitive assessments were conducted approximately 2 years later; information was complete for 5,573 women at the time of analysis, with 94% follow-up. We used linear and logistic regression to calculate multivariate-adjusted mean differences as well as odds of cognitive impairment (defined as worst 10% of test distribution) and of substantial decline in performance (worst 10% of distribution), across various levels of education and income. After adjusting for numerous potential confounding factors, we found strong trends of increasing mean cognitive performance with increasing level of education (p trend<0.0005 on all cognitive measures). Odds of cognitive impairment also consistently decreased with increasing education. For income, we found significant trends of increasing mean cognitive performance with increasing income on the summary score and on episodic memory (p trends<0.0001). Results were generally similar for cognitive decline over 2 years, although slightly weaker. Thus, in these well-educated, professional women, educational attainment and income both predicted cognitive function and decline.