Higher serum uric acid is associated with increased arterial stiffness in Japanese individuals

Abstract

Hyperuricemia is postulated to be a risk factor for atherosclerotic diseases, although whether it is independent of classical atherogenic risk factors is controversial. The automatic computer-assisted measurement of brachial-ankle pulse wave velocity (baPWV) is a valid and reproducible method by which to assess arterial stiffness, a potential surrogate marker of early atherosclerosis. By analyzing cross-sectional data from 982 individuals who underwent health screening, we have investigated whether serum uric acid is associated with high baPWV, which was determined as the highest quartile of baPWV values, in a sex-specific manner. Multivariate analysis showed that the odds ratios (95% CI) of the highest baPWV quartile across the sex-specific quartiles of serum uric acid were 1.0, 2.80 (0.93–8.40), 2.13 (0.74–6.19), and 2.76 (1.01–7.55) in women, and 1.0, 1.10 (0.55–2.20), 1.97 (1.04–3.75), and 2.24 (1.10–4.56) in men after adjusting for age, total and HDL-cholesterol, BMI, systolic blood pressure, triglycerides, fasting glucose and smoking status. The association between uric acid and high baPWV was observed in both subjects with metabolic syndrome and those without. These data suggest that in both genders, serum uric acid level is associated with increased baPWV, a marker of arterial stiffness, and is in part independent of other conventional risk factors for atherosclerosis and metabolic syndrome.

Introduction

Aortic pulse wave velocity (PWV) and augmentation index are indices of arterial stiffness, and are a predictor for cardiovascular diseases, stroke, and cognitive impairment [1], [2], [3]. Recent studies have shown that brachial-ankle PWV (baPWV), which can be measured fairly reproducibly by an automated device [4], well correlates well with aortic stiffness determined by an invasive method [5]. Because of their non-invasive nature, both baPWV measurements and carotid artery ultrasonography are used to assess arteriosclerosis during health screening. Several risk factors for increased PWV have been reported, including raised C-reactive protein (CRP) levels [6], menopause [7], and increased vascular calcification observed in patients with end-stage renal disease (ESRD) [8].

Several previous studies have suggested that hyperuricemia is a risk factor for cardiovascular diseases [9], [10]. Hyperuricemia increases the risk for metabolic syndrome, which has reported to be a risk factor for cardiovascular disease [11], [12]. Therefore, it is possible that observed association between uric acid (UA) and atherosclerotic disease may be in part attributed to the link between hyperuricemia and metabolic syndrome. On the other hand, however, recent studies also suggested that association between serum UA and death from cardiovascular disease and that between serum UA and carotid plaque may be independent of variables related to metabolic syndrome [13], [14].

It has recently been reported that metabolic syndrome is a strong risk factor for increased baPWV [15]. Thus, in the present study, we have investigated whether serum UA is associated with increased baPWV, and the independency of this association from metabolic syndrome as well as classical risk factors.