Aging and Functional Health Literacy: A Systematic Review and Meta-Analysis

Objectives: To review the evidence on the association between age and limited health literacy, overall and by health literacy test, and to investigate the mediating role of cognitive function. Method: The Embase, MEDLINE, and PsycINFO databases were searched. Eligible studies were conducted in any country or language, included participants aged >= 50 years, presented a measure of association between age and health literacy, and were published through September 2013. Results: Seventy analyses in 60 studies were included in the systematic review; 29 of these were included in the meta-analysis. Older age was strongly associated with limited health literacy in analyses that measured health literacy as reading comprehension, reasoning, and numeracy skills (random-effects odds ratio [OR] = 4.20; 95% confidence interval [CI]: 3.13-5.64). By contrast, older age was weakly associated with limited health literacy in studies that measured health literacy as medical vocabulary (random-effects OR = 1.19; 95% CI: 1.03-1.37). Evidence on the mediating role of cognitive function was limited. Discussion: Health literacy tests that utilize a range of fluid cognitive abilities and mirror everyday health tasks frequently observe skill limitations among older adults. Vocabulary-based health literacy skills appear more stable with age. Researchers should select measurement tests wisely when assessing health literacy of older adults.