ABC | Volume 111, Nº6, December 2018

Original Article Ferreira et al Uric acid and cardiovascular risk factors Arq Bras Cardiol. 2018; 111(6):833-840 Table 1 – Comparison of participants’ characteristics according to diagnosis of hyperuricemia Control group (n = 130) Hyperuricemia group (n = 19) p Male sex, n (%) 19 (14%) 6 (32%) 0.06 Alcohol intake, n (%) 44 (34%) 9 (47%) 0.30 Physical activity, n (%) 19 (14%) 2 (13%) 0.93 Non-white ethinicity, n (%) 83 (64%) 14 (74%) 0.40 Age (years) 34.00 (27.00 - 42.50) 31.00 (27.00 – 43.00) 0.93 Serum uric acid (mg/dL) 4.32 ± 1.09 7.18 ± 0.67 < 0.001 Serum urea (mg/dL) 29.31 ± 17.02 29.73 ± 8.28 0.84 Serum creatinine (mg/dL) 0.80 ± 0.17 0.83 ± 0.16 0.56 Values as mean ± standard deviation for normal distribution or as median (interquartile interval) for not normal distribution or absolute values (%). p: Control group vs.Hyperuricemia group. Statistical methods Participants were stratified into two groups according to their SUA levels: control group and hyperuricemia group. The control group was formed by men and women presenting SUA ≤ 7 and ≤ 6 mg/dL, respectively, whilst the hyperuricemia group consisted of men and women with SUA > 7 and > 6 mg/dL, respectively. Mean values and standard deviations were used to summarize continuous variables with normal distribution, while median and interquartile interval were used to summarize variables with non-normal distribution. Normality was tested by the Shapiro-Wilk test. The differences between groups were analyzed using unpaired Student’s t-test or Mann‑Whitney test, as appropriate. Multiple regression was used to adjust for confounding factors, including age, gender and BMI. Categorical variables were expressed as percentage and compared by X 2 test. 2 Pearson’s or Spearman’s correlation coefficient was performed to analyze the degree of association of SUA and anthropometric indices, laboratory variables, blood pressure and endothelial function among all participants. Partial correlations controlled for different confounders, including parameters of body adiposity, were also used. Statistical analyses were carried out through STATA version 12.0 (STATA Corp., College Station, TX, USA) and a P-value < 0.05 was considered statistically significant. Sample size was determined by convenience. Results A total of 149 volunteers were included in the statistical analysis. Their average age was 35.02 ± 9.57 years, mean BMI of 31.17 ± 5.87 kg/m 2 and mean SUA levels were 4.67 ± 1.41 mg/dL. Participants in control group (n = 130) and in hyperuricemia group (n = 19) were comparable in age, gender, alcohol intake, physical activity, ethnicity and serum levels of urea and creatinine (Table1). Dietary intake of energy and carbohydrates were significantly higher in hyperuricemia group than in control group, while the intake of monounsaturated fatty acids was significantly lower. However, after adjustments for age, sex and BMI these differences were no longer significant (Table 2). Individuals in hyperuricemia group compared with those in control group exhibited significantly higher BMI even after controlling for age and sex, regarded as variables able to interfere with theses parameters (Table 3). WC was higher in hyperuricemia group after controlling for age but not after further adjustment for sex. Comparative analysis of biochemical variables between hyperuricemia group and control group showed similar serum levels of glucose, insulin, HOMA-IR, total cholesterol, LDL-cholesterol, TG and hs-CRP. HDL-cholesterol was higher in control group only before adjustments for age, sex and BMI (Table 4). As compared to subjects in control group, those in hyperuricemia group still exhibited significantly lower levels of MDA, after adjustments for potential confounders (age, sex and BMI) (Table 4). The evaluation of endothelial function revealed significantly lower values of RHI in the hyperuricemia group than in control group even after adjustments for confounders. Mean values of systolic and diastolic blood pressure were similar in both study groups (Table 4). Considering data from all participants (n = 149), correlation analyses of SUA with laboratory variables, blood pressure and endothelial function revealed some significant associations (Table 5). SUA was directly associated with BMI, WC, glucose, total cholesterol, LDL-cholesterol, TG, MDA, systolic blood pressure and diastolic blood pressure. It was inversely correlated with HDL-cholesterol, adiponectin and RHI. After adjustment for age and sex the association of uric acid with BMI and WC remained significant. The positive associations of SUA with triglycerides and MDA, and negative associations with HDL-cholesterol, adiponectin, and RHI also remained significant after adjustment for age, sex and BMI (Table 5). Discussion In the present study carried out in healthy young and middle-aged adults, subjects with hyperuricemia, as 835