Associations of sedentary behavior and physical activity with serum uric acid in middle-aged and older adults with and without chronic kidney disease.

BACKGROUND: Elevated serum uric acid (UA) level is a major health risk, and its accumulation is exacerbated by impaired renal function. Physical activity is a modifiable determinant of serum UA levels. This study used an isotemporal substitution model to examine the associations of reallocating time between activity behaviors with serum UA levels in middle-aged and older adults with and without chronic kidney disease (CKD). METHODS: A total of 294 middle-aged and older adults with and without CKD (45-85 years) were recruited. Sedentary behavior (SB), light-intensity physical activity (LPA), and moderate-to-vigorous-intensity physical activity (MVPA) were objectively measured using a triaxial accelerometer. Serum UA levels were assessed from fasting blood samples. RESULTS: Higher SB and lower LPA were significantly associated with elevated serum UA levels. In contrast, MVPA was not significantly associated with serum UA levels. In isotemporal substitution models, replacing 30 min/day of SB with an equivalent duration of LPA was associated with lower serum UA levels (β = -0.057, P = 0.008). Substituting SB with MVPA was not significantly associated with serum UA levels (β = 0.048, P = 0.466). Stratified analyses revealed that the substitution of SB with LPA was significantly associated with lower serum UA levels among participants with CKD, whereas no significant association was observed among those without CKD. CONCLUSIONS: SB was associated with higher serum UA levels, whereas LPA demonstrated a favorable association. Replacing 30 min/day of SB with LPA was associated with lower serum UA levels, particularly among individuals with CKD.