Uric acid and inflammatory markers in the elderly from the inCHIANTI study

Aim: The role of uric acid (UA) in the process of atherosclerosis and atherotrombosis is controversial. Epidemiological studies have recently shown that UA may be a risk factor for cardiovascular diseases and a negative prognostic marker for mortality in subjects with pre-existing heart failure. Methods: We evaluated a relationship between UA levels and several inflammatory markers in 957 subjects, free of severe renal failure, from a representative Italian cohort of persons aged 65-95. Plasma levels of UA and white blood cell (WBC) and neutrophil count, C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1ra), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6r), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) were measured. Complete information on potential confounders was collected using standard methods. Results: WBC (p = 0.0001), neutrophils (p > 0.0001), CRP (p < 0.0001), IL-1ra (p < 0.0001), IL-6 (p = 0.0004), sIL-6r (p = 0.002), IL-18 (p < 0.0001), TNF-α (p = 0.0008), and the percentage of subjects with abnormally high levels of CRP (p = 0.004) and IL-6 (p < 0.0001) were significantly higher across UA quintiles. After adjustment for age, sex, behaviour- and disease-related confounders, results were virtually unchanged. In subjects with UA within the normal range, UA was significantly and independently associated with neutrophil count, CRP, IL-6, IL-1ra, IL-18, and TNF-α, whereas non-significant trends were observed for WBC (p = 0.1) and sIL-6r (p = 0.2). Conclusion: A positive and significant association between UA and several inflammatory markers was found in a large population-based sample of older persons and in a sub-sample of participants with normal UA. Accordingly, the prevalence of abnormally high levels of C-reactive protein and IL-6 increased significantly across UA quintiles.