Social resources and cognitive decline in a population of older African Americans and whites.

To examine the relation of social resources and cognitive decline in older adults. Data are from the Chicago Health and Aging Project, an epidemiologic study of risk factors for Alzheimer disease (AD) and other common conditions in a geographically defined population of older persons. The sample consisted of 6,102 non-Hispanic African Americans (61.2%) and whites, aged > or = 65, who underwent up to three interviews during an average of 5.3 years of follow-up. Each interview included administration of four cognitive function tests from which a composite measure of cognition was formed. Social networks were based on the number of children, relatives, and friends seen at least once a month. Social engagement was measured with four items related to social and productive activity. Higher number of social networks and level of social engagement were positively correlated with initial level of cognitive function (networks estimate = 0.003, engagement estimate = 0.060, both p < 0.001). Both resources were also associated with a reduced rate of cognitive decline. A high (90th percentile) number of networks reduced the rate of decline by 39% compared to a low level (10th percentile), and high social engagement reduced decline by 91%. These relations remained after controlling for socioeconomic status, cognitive activity, physical activity, depressive symptoms, and chronic medical conditions. Greater social resources, as defined by social networks and social engagement, are associated with reduced cognitive decline in old age.