Ethnic Differences in Cognitive Function Over Time

PURPOSE: Minority group membership in old age has been implicated as a risk factor for lower scores on cognitive function tests, independent of education level. In addition, differential rates of cognitive decline by ethnic group have been identified in several epidemiologic studies. However, others have not been able to detect differences. METHODS: In order to determine if health disparities in cognitive function scores extend to rates of decline, the current research examined rates of change in memory and mental status over the course of 9 years (1996-2004) in a nationally representative sample of late middle-aged and older white, black, and Hispanic adults who were part of the nationally representative Health and Retirement Study. Change in cognitive function was measured by separate indices of memory and mental status items and analyzed with multivariable mixed modeling. RESULTS: Results indicated that, after controlling for demographic, social, and health-related variables, ethnicity was associated with cognitive function scores across waves (P < 0.01), but did not greatly impact rates of decline. Furthermore, although education was associated with cognitive function scores across waves (P < 0.01), education level did not impact decline rates. CONCLUSIONS: Some health disparities in cognitive function exist even in late middle age, but ethnic differences in rates of decline are mixed. Ann Epidemiol 2009; 19:778-783. (C) 2009 Elsevier Inc. All rights reserved.