Experiences at Every Stage of Life Influence Mental Function in Advanced Age
Most people will experience a decline in their mental abilities as they reach advanced age, but the rate and severity of decline differ tremendously from one person to another. Understanding the factors that explain these differences is of interest because they may provide insight into strategies for extending the healthy life span of the aging population.
Although diseases such as Alzheimer's disease undoubtedly drive the severe decline that some people experience, there is reason to think that an individual's life circumstances, experiences, and lifestyle behaviors may also play a role in determining his or her cognitive function in advanced age.
Because ethnicity and race are associated with large average differences in multiple aspects of life — economic, educational, recreational — studying diverse populations offers a way to better understand the effects of life experience on cognitive aging.
Previous studies have reported increased risk of cognitive impairment and dementia in ethnic minorities, whereas other studies have suggested that this finding may reflect differences in socioeconomic status (SES), educational experience, and patterns of physical and mental activity in adulthood. However, the relative contributions of lifestyle factors that are experienced over the course of a person's life to his or her subsequent late-life cognition are not known.
In 2012, an international group of researchers with an interest in aging and diversity convened a workshop to study this issue. Using data from the University of California, Davis, the group examined demographic factors along with broader reflectors of life experience, including measures of childhood SES, adult literacy (a measure of educational attainment), and engagement in lifelong physical and mental activity.
The results of this study, published recently in Neuropsychology (Brewster et al., 2014), indicate support for the notion that demographic differences in cognitive ability reflect broader socioeconomic factors and behavior patterns throughout life.
For example, although non-Latino Whites scored higher on cognitive tests than did the other ethnic groups, much of this effect disappeared when childhood SES, adult literacy, and extent of physical activity during adulthood were considered.
Predictors of change in patterns of recreational activity emerged as important. Less decline was experienced by persons who reported doing more of these activities in late life and who maintained their level of activities better from middle age to old age. Older persons and persons who carried a gene related to Alzheimer's disease declined more quickly.
This study shows that multiple factors — from every stage of life — influence cognitive ability in advanced age. Thus, the results suggest that ethnically related disparities in cognitive disorders of aging might be reduced by improvements in education and the economic circumstances of children.
At the same time, the choices adults make regarding their leisure time in middle age, and even in old age, continue to make a difference in cognitive function.
Citation:
Brewster, P. W. H., Melrose, R. J., Marquine, M. J., Johnson, J. K., Napoles, A., MacKay-Brandt, A., Farias, S., Reed, B., & Mungas, D. (2014). Life experience and demographic influences on cognitive function in older adults. Neuropsychology. Advance online publication. doi: 10.1037/neu0000098opens in new window
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