ABCs or 123s? The independent contributions of literacy and numeracy skills on health task performance among older adults

OBJECTIVE: To investigate the relationship between literacy and numeracy and their association with health task performance. METHODS: Older adults (n = 304) completed commonly used measures of literacy and numeracy. Single factor literacy and numeracy scores were calculated and used to predict performance on an established set of health self-management tasks, including: (i) responding to spoken information; (ii) comprehension of print and (iii) multimedia information; and (iv) organizing and dosing medication. Total and sub-scale scores were calculated. RESULTS: Literacy and numeracy measures were highly correlated (rs = 0.68; ps < 0.001). In multivariable models adjusted for age, gender, race, education, and comorbidity, lower literacy (β = 0.44, p < 0.001) and numeracy (β = 0.44, p < 0.001) were independently associated with worse overall task performance and all sub-scales (literacy range, β = 0.23–0.45, ps < 0.001; numeracy range, β = 0.31–0.41, ps < 0.001). Multivariable analyses with both constructs entered explained more variance in overall health task performance compared with separate literacy and numeracy models (8.2% and 10% respectively, ps < 0.001). CONCLUSION: Literacy and numeracy were highly correlated, but independent predictors of health task performance. These skill sets are complementary and both are important for health self-management. PRACTICE IMPLICATIONS: Self-management interventions may be more effective if they consider both literacy and numeracy skills rather than focusing on one specific ability.