Does physical activity mediate the association of health literacy with cognition in older adults?

BACKGROUND: Health literacy (HL), defined as the ability to find, understand, and use health-related information and services, is positively associated with global cognitive functioning and healthy behaviours. Also, current evidence suggests that physical activity may prevent or delay cognitive decline and dementia. This study explores the mediating role of physical activity in the relationship between HL and cognition in a representative sample of older adults aged 58+ living in Switzerland. METHODS: We used data from 1,603 respondents to Wave 8 (2019/2020) of the Survey on Health, Ageing, and Retirement in Europe (SHARE) in Switzerland. HL was assessed using the HLS-EU-Q16 questionnaire. Mild cognitive impairment (MCI) was defined as 1.5-standard deviation below the mean of the age- and education-specific global cognition score. Physical activity was self-reported based on a question on the frequency of engagement in activities requiring a moderate level of energy. The associations between these three variables were assessed using separate probit regression models, controlling for social, health, and regional characteristics. A causal mediation analysis with parametric regression models was used to test the mediation hypothesis. RESULTS: Preliminary results showed that lower levels of HL were associated with a lower likelihood of being engaged in physical activity (p < 0.05) and with a higher likelihood of having MCI (p < 0.05). In addition, being engaged in physical activity was associated with a lower probability of having MCI (p < 0.01). Causal mediation analysis indicated that 30% of the association between low HL and MCI was mediated by physical activity. CONCLUSIONS: Given the mediating role of physical activity in the relationship between low HL and MCI, improving HL in older adults may foster engagement in physical activity, which could act as a protective factor in MCI. KEY MESSAGES: • Improving health literacy may have the potential to foster engagement in physical activity and may contribute to the prevention of mild cognitive impairment. • Healthy aging programs should not only promote physical activity as a preventive measure to reduce or delay cognitive decline but focus on strengthening individuals’ health literacy skills.