Association between low functional health literacy and mortality in older adults: longitudinal cohort study

Objective To investigate the association between low functional health literacy (ability to read and understand basic health related information) and mortality in older adults. Design Population based longitudinal cohort study based on a stratified random sample of households. Setting England. Participants 7857 adults aged 52 or more who participated in the second wave (2004-5) of the English Longitudinal Study of Ageing and survived more than 12 months after interview. Participants completed a brief four item test of functional health literacy, which assessed understanding of written instructions for taking an aspirin tablet. Main outcome measure Time to death, based on all cause mortality through October 2009. Results Health literacy was categorised as high (maximum score, 67.2%), medium (one error, 20.3%), or low (more than one error, 12.5%). During follow-up (mean 5.3 years) 621 deaths occurred: 321 (6.1%) in the high health literacy category, 143 (9.0%) in the medium category, and 157 (16.0%) in the low category. After adjusting for personal characteristics, socioeconomic position, baseline health, and health behaviours, the hazard ratio for all cause mortality for participants with low health literacy was 1.40 (95% confidence interval 1.15 to 1.72) and with medium health literacy was 1.15 (0.94 to 1.41) compared with participants with high health literacy. Further adjustment for cognitive ability reduced the hazard ratio for low health literacy to 1.26 (1.02 to 1.55). Conclusions A third of older adults in England have difficulties reading and understanding basic health related written information. Poorer understanding is associated with higher mortality. The limited health literacy capabilities within this population have implications for the design and delivery of health related services for older adults in England.