Financial and Health Literacy Predict Incident Alzheimer’s Disease Dementia and Pathology

Abstract

Background Domain specific literacy is a multidimensional construct that requires multiple resources including cognitive and non-cognitive factors. Objective We test the hypothesis that domain specific literacy is associated with AD dementia and AD pathology after controlling for cognition. Methods Participants were community based older persons who completed a baseline literacy assessment, underwent annual clinical evaluations for up to 8 years and agreed to organ donation after death. Financial and health literacy was measured using 32 questions and cognition was measured using 19 tests. Annual diagnosis of AD dementia followed standard criteria. AD pathology was examined post-mortem by quantifying plaques and tangles. Cox models examined the association of literacy with incident AD dementia. Performance of model prediction for incident AD dementia was assessed using indices for integrated discrimination improvement and continuous net reclassification improvement. Linear regression models examined the independent association of literacy with AD pathology in autopsied participants. Results All 805 participants were free of dementia at baseline and 102 (12.7%) developed AD dementia during the follow-up. Lower literacy was associated with higher risk for incident AD dementia (p<0.001), and the association persisted after controlling for cognition (Hazard Ratio=1.50, p=0.004). The model including the literacy measure had better predictive performance than the one with demographics and cognition only. Lower literacy also was associated with higher burden of AD pathology after controlling for cognition (β=0.07, p=0.035). Conclusion Literacy predicts incident AD dementia and AD pathology in community-dwelling older persons, and the association is independent of traditional measures of cognition.

Genetic Contributions To Health Literacy

“…A strength of the current study is that we use GWAS summary results from a large number of cognitive and health-related traits which enabled a comprehensive investigation of the shared genetic influences between health literacy, cognitive function and health. Whereas phenotypic associations between health literacy and health-related traits such as type 2 diabetes 5 and Alzheimer's disease 7,8 have been identified, we did not find that genetic variants previously associated with these healthrelated traits were associated with health literacy in this study. One limitation of the current study is that the quality of the polygenic profile scores created depend on the quality of the original GWAS.…”

“…6 One study 5 found that individuals with inadequate health literacy were 48% more likely to report a diagnosis of diabetes and 69% more likely to report having heart failure, compared to those with adequate health literacy, after adjusting for sociodemographic variables and health behaviours. Using prospective studies, lower health literacy predicted incident dementia 7,8 and risk of dying. 4,9,10 Compared with those of health literacy, similar associations with health have been found for cognitive function.…”

“…Cognitive function has been consistently found to attenuate the size of the association between health literacy and health; however, whereas some studies have found that health literacy no longer predicted better health when controlling for cognitive GENETIC CONTRIBUTIONS TO HEALTH LITERACY 4 function, 33,[35][36][37] others have found that a small but significant association remained between higher health literacy scores and better health when also controlling for cognitive function. 7,10,33,38,39 Whereas there is a wealth of evidence reporting a relationship between health literacy, cognitive function and health, it is less well understood why these associations are found. One possibility is that they share genetic influences.…”

Genetic Contributions to Health Literacy

“…One study (Wolf et al, 2005) found that individuals with inadequate health literacy were 48% more likely to report a diagnosis of diabetes and 69% more likely to report having heart failure, compared to those with adequate health literacy, after adjusting for sociodemographic variables and health behaviors. Using prospective studies, lower health literacy predicted incident dementia (Kaup et al, 2014;Yu et al, 2017) and risk of dying (Baker et al, 2007;Berkman et al, 2011;Bostock & Steptoe, 2012).…”

Expanding the Toolkit for Studies of Aging

“…Notably, they complement an emerging body of data showing that aging affects a broad array of behaviors beyond those traditionally included in studies of aging (e.g., cognition). In particular, higher order adaptive skills such as financial and healthcare decision making that require coordination of diverse skills and resources are particularly vulnerable to early disease-related changes and have important prognostic implications among older persons (2, 3). Taken together with this study, these data suggest that assessment of complex IADLs and higher order abilities such as decision making that are essential for independence may aid in the early identification of persons likely to experience adverse cognitive and other health outcomes in old age.…”