Racial differences in the progression of cognitive decline in Alzheimer disease

Objective: Alzheimer disease ( AD) is the leading cause of dementia in older persons, but little is known about racial differences in its clinical manifestations. The purpose of the current study was to examine the association of race with rate of cognitive decline in AD. Methods: Older persons with clinically diagnosed AD were recruited from healthcare settings. At 6-month intervals for up to 4 years, they completed a battery of nine cognitive tests from which a previously established measure of global cognition was derived. Follow-up data were available on 452 participants ( 27.6% African American, 68.8% women), 88.1% of those eligible. Results: A growth curve approach was used to estimate individual paths of change in global cognition. In a model that controlled for age and education, African Americans had a lower level of global cognition at baseline than non-African Americans, but declined at a 25% slower rate on average. In additional models, there was no indication that the association of race with cognitive decline varied by age, gender, or education. Conclusion: The rate of cognitive decline in AD appears to be slower in African Americans than non-African Americans.