Associations between serum uric acid and markers of subclinical atherosclerosis in young adults. The cardiovascular risk in Young Finns study

Background and methods: Serum uric acid (SUA) is a suggested biomarker for established coronary artery disease, but the role of SUA in early phases of atherosclerosis is controversial. The relations of SUA with vascular markers of subclinical atherosclerosis, including carotid artery intima-media thickness (cIMT), carotid plaque, carotid distensibility (Cdist) and brachial flow-mediated dilatation (FMD) were examined in 1985 young adults aged 30-45 years. In addition to ordinary regression, we used Mendelian randomization techniques to infer causal associations. Results: In women, the independent multivariate correlates of SUA included BMI, creatinine, alcohol use, triglycerides, glucose and adiponectin (inverse association) (Model R2 = 0.30). In men, the correlates were BMI, creatinine, triglycerides, C-reactive protein, alcohol use, total cholesterol and adiponectin (inverse) (Model R2 = 0.33). BMI alone explained most of the variation of SUA levels both in women and men (Partial R2 ∼ 0.2). When SUA was modeled as an explanatory variable for vascular markers, it directly associated with cIMT and inversely with Cdist in age- and sex-adjusted analysis. After further adjustments for BMI or glomerular filtration rate, these relations were reduced to non-significance. No associations were found between SUA and FMD or the presence of a carotid plaque. Mendelian randomization analyses using known genetic variants for BMI and SUA confirmed that BMI is causally linked to SUA and that BMI is a significant confounder in the association between SUA and cIMT. Conclusion: SUA is associated with cardiovascular risk markers in young adults, especially BMI, but we found no evidence that SUA would have an independent role in the pathophysiology of early atherosclerosis.