Education and Literacy as Risk Factors of Dementia after Stroke and Transient Ischemic Attack: NEDICES Study.

BACKGROUND A protective effect of education on cognitive decline after stroke has been claimed, but evidence from prospective population-based cohorts is very limited. The differential role of literacy and education on dementia after stroke remains unexplored. OBJECTIVE This research addresses the role of education and literacy in dementia incidence after stroke and transient ischemic attack (TIA). METHODS 131 participants with stroke or TIA were identified within the population-based NEDICES study (N = 5,278 persons). Participants were fully assessed at baseline (1994-1995) and incident dementia diagnosis was made by expert neurologists (DSM-IV criteria) after a mean follow-up of 3.4 years. Adjusted Cox regression analyses were applied to test the association between education, literacy, and dementia risk. RESULTS Within the 131 subjects with stroke or TIA, 19 (14%) developed dementia at follow-up. The Cox's regression model (age and sex adjusted) showed that low education (HR = 3.48, 95% CI = 1.28, 9.42, p = 0.014) and literacy (HR = 3.16, 95% CI = 1.08, 9.22, p = 0.035) were significantly associated with a higher dementia risk. Low education was also associated with dementia when main confounders (i.e., cognitive/functional performance) were considered in the Cox's model. However, after including stroke recurrence, only low/null literacy (versus education) remained as significant predictor of dementia. Finally, low/null literacy showed an effect over-and-above education on dementia risk when both factors were introduced in the adjusted Cox's regression. CONCLUSION These findings underline the importance of literacy to estimate cognitive decline after stroke in low-educated populations.