Does cognitive functioning mediate the well-documented link between education and functional disability in middle-aged adults?

Wide bodies of literature document gradients in the experience of disease and function by levels of education and other measures of socioeconomic status: The lower a person’s education, the more likely the person will suffer from a greater variety and severity of diseases as well as functional disability arising from those diseases. It is unclear whether education proxies for other indicators of SES (income, net worth) or measures all the knowledge and skills accumulated over the life course that may be health protective. For example, because education and cognitive functioning are often perceived as two sides of the same coin, cognitive functioning may also measure life course knowledge and skills. The dimension of cognitive functioning that reflects a person’s fluid or basic processing abilities promotes the acquisition of new information that, in turn, is reflected in the dimension of crystallized or knowledge-based abilities. Both dimensions of cognitive functioning are likely to influence the amount of education that a person achieves; conversely, the amount of education achieved (as well as other life course experiences) may influence a person’s cognitive functioning. The moderate correlation between education and cognitive functioning ( r = 0.44) in middle-aged adults suggests that although they are complementary, they may tap into different conceptual realms. Earlier research by the authors 1 demonstrated that high levels of cognitive functioning behave like high levels of education in associations with enhanced health outcomes in middleaged adults. Further, cognitive functioning—like education—moderates the effects of some diseases on the reporting of functional disability. 2