An estimated 11% of U.S. adults aged 65 or older have dementia, and as the population ages, dementia cases are predicted to nearly double from 5.2 million in 2019 to 10.2 million by 2050. Understanding how education levels may affect cognitive decline and presumably dementia is important for projecting future dementia in the population and potentially helping individuals understand and possibly reduce their risk.

Prior research has suggested a link between more schooling and better later-life performance on cognitive tests. However, most of these studies provided suggestive associations rather than causal estimates. When prior studies did provide causal estimates, inferences were generally based on changes in educational levels after compulsory schooling laws were enacted. This limited estimated causal effects of schooling to the lower grade levels targeted by the laws and the individuals affected by them.

In this study, the authors expanded the evidence about causal effects of schooling on older adults to higher levels of schooling, such as attending college, and to a broader population. The authors applied advanced methods to data from a national, longitudinal cohort study representative of U.S. individuals over age 50.