Association Between Serum Uric Acid and Vitamin C Levels in Adults With Metabolic Syndrome

Metabolic syndrome (MetS) comprises several interrelated cardiometabolic abnormalities, including central obesity, elevated blood pressure, dyslipidemia, and impaired glucose metabolism. Serum uric acid (SUA) concentrations are frequently elevated in individuals with MetS, while vitamin C is a water-soluble antioxidant that may be associated with urate metabolism. Limited evidence is available concerning the relationship between circulating vitamin C and SUA among Pakistani adults with MetS. This cross-sectional study investigated the correlation between serum vitamin C and SUA and evaluated the association after adjustment for selected cardiometabolic factors. The study was conducted in the Department of Medicine at Hameed Latif Hospital, Lahore, between April and July 2026. A total of 120 adults aged 18–80 years were recruited using consecutive sampling. Demographic, anthropometric, clinical, and biochemical information was obtained. Fasting venous blood samples were collected to measure SUA and serum vitamin C, and dietary vitamin C intake was estimated with a food-frequency questionnaire. Pearson correlation coefficients and multivariable linear regression were used for analysis. The mean age was 49.6 ± 11.2 years, and the mean BMI was 31.4 ± 4.7 kg/m2. Mean SUA and serum vitamin C concentrations were 6.41 ± 1.38 mg/dL and 0.42 ± 0.18 mg/dL, respectively. Hyperuricemia was identified in 41.7% of participants, while vitamin C deficiency and insufficiency were observed in 28.3% and 46.7%, respectively. Serum vitamin C and SUA were inversely correlated in the total sample (r = -0.34, p < 0.001), among men (r = -0.37, p = 0.003), and among women (r = -0.29, p = 0.027). Following adjustment for age, sex, BMI, blood pressure, triglycerides, HDL cholesterol, and fasting glucose, every 0.1 mg/dL higher serum vitamin C concentration was associated with an estimated 0.19 mg/dL lower SUA (reported coefficient = -0.19; 95% CI: -0.28 to -0.10; p < 0.001). These findings identify a significant inverse association between serum vitamin C and SUA in the selected study population. Because the design was cross-sectional and no treatment was assigned, the findings do not establish a urate-lowering effect of vitamin C. Larger prospective and interventional investigations are needed to clarify the clinical implications.