Associations of dietary patterns, dietary motivations, and nutritional status with skeletal muscle mass in Chinese older adults: A structural equation modeling study.

OBJECTIVES: This study aimed to explore the relationships between dietary patterns, motivation, nutritional status, and skeletal muscle mass guided by the Self-Determination Theory. METHODS: This study employed a cross-sectional design. We invited 249 older adults using the convenience sampling method from suburban and rural areas of Hunan Province from April to December 2023. Data were collected using the Eating Motivation Survey (TEMS), the Mini Nutritional Assessment-Short Form (MNA-SF), and the Chinese version of the Food Frequency Questionnaire (FFQ). Bioelectrical Impedance Analysis was used to assess body composition, with skeletal muscle mass standardized using the Relative Skeletal Muscle Index (RSMI). Principal component analysis (PCA) was employed to extract dietary patterns, and structural equation modeling (SEM) was used to assess interaction paths. RESULTS: Two distinct dietary patterns emerged. Dietary motivation-shaped by gender and educational background-exhibited significant direct effects on skeletal muscle mass (β = 0.162, P < 0.001), nutritional status (β = 0.278, P < 0.001), and dietary patterns (pattern 1: β = 0.124, P = 0.050; pattern 2: β = 0.272, P < 0.001). Dietary patterns also had direct effects skeletal muscle mass (pattern 1: β = 0.338, P < 0.001; pattern 2: β = 0.430, P < 0.001). Moreover, dietary patterns directly affect nutritional status (pattern 1: β = 0.064, P < 0.001; pattern 2: β = 0.649, P < 0.001), and nutritional status exerted a significant direct effect on skeletal muscle mass (β = 0.177, P = 0.008), supporting a further indirect pathway from dietary patterns to skeletal muscle mass via nutritional status. CONCLUSIONS: Dietary motivation can directly influence dietary patterns. Both dietary motivation and dietary patterns can directly affect skeletal muscle mass and also have indirect effects by improving nutritional status. These findings underscore the necessity for tailored, motivation-based interventions in older adults to enhance dietary adherence and muscle health outcomes.