Age, residential, and socioeconomic differences in the association between nutritional literacy and physical activity among adults

Nutrition literacy (NL) and physical activity (PA) are two crucial modifiable factors in the prevention of chronic disease. This research was designed to evaluate the potential associations between them. The cross-sectional investigation was carried out from May to July 2023 in Bengbu, China. NL was evaluated via the short-form nutrition literacy scale and categorized into four groups (Q1–Q4) based on score quartiles. PA was evaluated via the short version of the international physical activity questionnaire and classified as low, moderate, or high according to the IPAQ-SF scoring criteria for categories. An ordinal logistic regression model was applied to test the relationship between NL and PA. In addition, restricted cubic spline (RCS) analysis with continuous NL scores and continuous total PA was performed to assess the overall and potential nonlinear associations. Among the 2102 participants included in the survey, 36.8% performed high-level PA. The odds of high-level PA were significantly higher among participants in the highest quartile than those in the lowest quartile of NL (OR = 1.63, 95% CI: 1.24–2.14). Regarding dimensions, PA was associated with nutritional knowledge, understanding, and interactive and critical skills. RCS analysis showed a significant overall association between the NL scores and total PA (P-overall < 0.001), without statistically significant evidence of non-linearity (P-nonlinearity = 0.084). Subgroup analyses further revealed that the association remained significant only among adults aged 65 or older, urban residents, individuals with at least a junior high school education, and those earning less than 1000 RMB per month. NL is positively associated with high-level PA, particularly interactive NL and critical NL. Furthermore, this relationship varies significantly by age, residence, educational level, and monthly income level. The results underline the need for interventions on NL tailored to specific demographic characteristics to encourage people to engage in high-level PA.