摘要：Objectives. We tested whether social integration protects against memory loss and other cognitive disorders in late life in a nationally representative US sample of elderly adults, whether effects were stronger among disadvantaged individuals, and whether earlier cognitive losses explained the association (reverse causation). Methods. Using data from the Health and Retirement Study (N = 16 638), we examined whether social integration predicted memory change over 6 years. Memory was measured by immediate and delayed recall of a 10-word list. Social integration was assessed by marital status, volunteer activity, and frequency of contact with children, parents, and neighbors. We examined growth-curve models for the whole sample and within subgroups. Results. The mean memory score declined from 11.0 in 1998 to 10.0 in 2004. Higher baseline social integration predicted slower memory decline in fully adjusted models ( P <.01). Memory among the least integrated declined at twice the rate as among the most integrated. This association was largest for respondents with fewer than 12 years of education. There was no evidence of reverse causation. Conclusions. Our study provides evidence that social integration delays memory loss among elderly Americans. Future research should focus on identifying the specific aspects of social integration most important for preserving memory. Memory loss is a prominent feature of aging and is associated with substantial declines in quality of life and increased risk of dementia, 1 , 2 institutionalization, 3 and mortality. 4 Few effective strategies for prevention or treatment have been identified. 5 Several studies have suggested that features of the social environment are important predictors of cognitive outcomes among the elderly (those aged 50 and older; for a review, see Fratiglioni et al. 6 ). For example, Fratiglioni et al. reported that limited social networks were associated with increased risk of incident dementia, 7 Barnes et al. found that high social networks and high social engagement reduced the rate of cognitive decline, 8 Bassuk et al. reported that individuals with many social ties were at lower risk of incident cognitive decline than were individuals with few social ties, 9 and results from Zunzunegui et al. indicated that elderly men and women with few social ties, poor social integration, and social disengagement were at greater risk of cognitive decline. 10 These strong studies clearly indicate the importance of social relations in shaping cognitive decline. We examined the association between social integration and memory loss in a large, representative sample of US residents born before 1948. We explored 3 related issues: whether the associations found in previous studies would be generalizable to a nationally representative sample of elderly in the United States, whether the effects would be stronger among individuals in socially and economically disadvantaged conditions, and whether the results could be attributable to reverse causation. Although it has limited clinical data, the Health and Retirement Study (HRS) provided an excellent opportunity to address these 3 issues.
