Relationship between serum uric Acid levels, metabolic syndrome, and arterial stiffness in korean

Uric acid and metabolic syndrome: Importance of hyperuricemia cut-off

BACKGROUND

The relationship between HyperUricemia (HU) and Metabolic Sindrome (MS) and if Uric Acid (UA) should be inserted into MS definitions is a matter of debate. Aim of our study was to evaluate the correlation between UA and HU with Insulin Resistance (IR) and MS in a population of hypertensive patients. HU was defined with two cut-offs (the classic one of ≥6 mg/dL for women and ≥ 7 for men; the newly proposed URRAH one with ≥5.6 mg/dL for both sexes).

METHODS

We enrolled 473 Hypertensive patients followed by the Hypertension Unit of San Gerardo Hospital (Monza, Italy). IR was defined through TG/HDL ratio and NCEP-ATP-III criteria were used for MS diagnosis.

RESULTS

MS was found in 33.6 % while HU affected 14.8 % of subjects according to the traditional cut-off and 35.9 % with the URRAH cut-off. 9.7 % (traditional cut-off) and 17.3 % (URRAH's threshold) of the subjects had both HU and MS. UA level was significantly higher in MS group (5.7 vs 4.9 mg/dL, p < 0.0001) as well as for HU (29.0 vs 7.6 % and 51.6 vs 28.0 %, for classic and URRAH cut-off respectively, p < 0.0001 for both comparison). Logistic multivariable regression models showed that UA is related to MS diagnosis (OR = 1.608 for each 1 mg/dL), as well as HU with both cut-off (OR = 5.532 and OR = 3.379, p < 0.0001 for all comparison, for the classic cut-off and the URRAH one respectively).

CONCLUSIONS

The main finding of our study is that UA and HU significantly relate to IR and MS. The higher the values of UA and the higher the cut-off used, the higher the strength of the relationship.

Burden of Metabolic Syndrome Among a Low-Income Population in China: A Population-Based Cross-Sectional Study

INTRODUCTION

Metabolic syndrome (MetS) is a chronic and complex disease associated with all-cause mortality, cardiovascular disease, and type 2 diabetes. The present study aimed to evaluate the prevalence of MetS and its risk factors among middle-aged and older adults in low-income, low-education rural areas with a high incidence of stroke.

METHODS

This cross-sectional study of the general population was performed from April 2019 to June 2019 in rural areas of Tianjin, China. All eligible residents aged ≥ 45 years and without active malignant tumors, hepatic failure, and severe renal disease underwent routine medical examinations, which included a questionnaire, physical examination, and routine blood and biochemical tests. The modified International Diabetes Federation criteria for the Asian population was used to identify patients with MetS.

RESULTS

A total of 3175 individuals (44.8% men, 55.2% women) were included in the final analysis. The prevalence of MetS was 52.8%, with higher prevalence in women than in men (62.4%and 40.9%, respectively). Of the five MetS components, high blood pressure and abdominal obesity were the two most prevalent in both women and men, accounting for 89.3% and 62.0%, respectively, followed by elevated fasting plasma glucose, low high-density lipoprotein cholesterol, and elevated triglycerides. Multivariate logistic regression analysis revealed the following traits to be risk factors for MetS: female sex, self-reported smoking, self-reported snoring, high body mass index, high waist-to-hip ratio, and high serum urate level.

CONCLUSION

The prevalence of MetS was quite high in rural areas with a low-income, low-education population. Implementing preventive and therapeutic interventions based on these risk factors is essential to prevent metabolic abnormalities.

Can biomarkers be used to improve diagnosis and prediction of metabolic syndrome in childhood cancer survivors? A systematic review

Childhood cancer survivors (CCS) are at increased risk to develop metabolic syndrome (MetS), diabetes, and cardiovascular disease. Common criteria underestimate adiposity and possibly underdiagnose MetS, particularly after abdominal radiotherapy. A systematic literature review and meta-analysis on the diagnostic and predictive value of nine newer MetS related biomarkers (adiponectin, leptin, uric acid, hsCRP, TNF-alpha, IL-1, IL-6, apolipoprotein B (apoB), and lipoprotein(a) [lp(a)]) in survivors and adult non-cancer survivors was performed by searching PubMed and Embase. Evidence was summarized with GRADE after risk of bias evaluation (QUADAS-2/QUIPS). Eligible studies on promising biomarkers were pooled. We identified 175 general population and five CCS studies. In the general population, valuable predictive biomarkers are uric acid, adiponectin, hsCRP and apoB (high level of evidence), and leptin (moderate level of evidence). Valuable diagnostic biomarkers are hsCRP, adiponectin, uric acid, and leptin (low, low, moderate, and high level of evidence, respectively). Meta-analysis showed OR for hyperuricemia of 2.94 (age-/sex-adjusted), OR per unit uric acid increase of 1.086 (unadjusted), and AUC for hsCRP of 0.71 (unadjusted). Uric acid, adiponectin, hsCRP, leptin, and apoB can be alternative biomarkers in the screening setting for MetS in survivors, to enhance early identification of those at high risk of subsequent complications.

Independent association of serum uric acid levels with arterial stiffness in the absence of established cardiovascular disorders

BACKGROUND

The impact of serum uric acid (SUA) on atherosclerosis has been suspected to be epiphenomenal owing to its close relationship with metabolic abnormalities. The aim of the present study was to evaluate the association between SUA levels and arterial stiffness in the absence of established cardiovascular (CV) disorders.

METHODS

The relationship between SUA levels and brachial-ankle pulse wave velocity (baPWV) was examined in 353 asymptomatic adults (57 ± 8 years, 11.9% men) without established CV disorders defined as systolic blood pressure (BP) ≥140 mmHg or diastolic BP ≥ 90 mmHg; total cholesterol ≥240 mg/dL; low-density lipoprotein cholesterol ≥160 mg/dL; high-density lipoprotein cholesterol <40 mg/dL; fasting glucose ≥126 mg/dL; body mass index ≥25.0 kg/m² ; current smoking; and history of medication for hypertension, diabetes, and dyslipidemia. Subjects were stratified into four groups based on the quartiles of their SUA levels.

RESULTS

Mean baPWV was significantly different in all groups: group I, 1320 ± 195 cm/s; group II, 1336 ± 195 cm/s; group III, 1404 ± 199 cm/s; and group IV, 1483 ± 248 cm/s (P < .001). SUA levels were significantly correlated with baPWV (r = .364) (P < .001). Multivariate linear regression analysis showed that SUA (β: 32.93; 95% confidence interval [CI]: 18.99-54.87), together with age (β: 11.44; 95% CI: 9.36-13.53) and systolic BP (β: 8.98; 95% CI: 6.80-11.16), was significantly associated with baPWV (P < .001).

CONCLUSIONS

High SUA levels have an independent association with increased arterial stiffness even in subjects without established CV disorders.

Incidence and Risk Factors of Hypogonadism in Male Patients With Latent Autoimmune Diabetes and Classic Type 2 Diabetes

OBJECTIVES

This study aimed to compare the prevalence of hypogonadism between male patients with latent autoimmune diabetes (LADA) and type 2 diabetes (T2DM) and investigate the risk factors for hypogonadism in these patients.

METHODS

This cross-sectional study evaluated 367 male patients with LADA (n=73) and T2DM (n=294) who visited the endocrinology department of Shanghai Tenth People's Hospital between January 2016 and October 2019 for diabetes management. Sex hormones, lipid profiles, sex hormone-binding globulin (SHBG), glycosylated hemoglobin A1c, beta-cell function, uric acid, and osteocalcin were determined in serum samples. Hypogonadism was defined as calculated free testosterone (cFT) less than 220 pmol/L along with the presence of symptoms (positive ADAM score).

RESULTS

The rate of hypogonadism in the LADA and T2DM group were 8.2, and 21.7%, respectively (p=0.017). After adjusting possible confounders, the rate of hypogonadism in the LADA group was comparable to those of the T2DM group. Univariate logistic regressions demonstrated that age, BMI, fasting C-peptide, triglycerides, total cholesterol and uric acid were associated with hypogonadism in men with diabetes, BMI, triglycerides and estradiol were independent risk for hypogonadism in men with diabetes.

CONCLUSION

This is the first evidence to explore the rate of hypogonadism in male patients with latent autoimmune diabetes (LADA). In the population requiring admission to a large urban hospital in China, the rate of hypogonadism was comparable to those of the T2DM group after adjusting for possible confounders. BMI, triglycerides and estradiol were independently associated with the presence of HH in male diabetic patients.

Uric acid and its correlation with hypertension in postmenopausal women: A multi-ethnic study (Observational study)

We investigate the association of uric acid with hypertension among Han, Uygur, and Kazakh populations in the Xinjiang Province of Western China. Our study aims to evaluate the relationships of serum uric acid (SUA) with hypertension in the Chinese population according to the menopausal status. Medical data of 1684 Han, 1895 Uygur, and 294 Kazakh people was examined. The prevalence of hypertension was calculated by the quartiles of SUA. Correlation between hypertension-related risk factors calculated and compared between men and women. SUA was higher in men than in women. The level was significantly higher in postmenopausal than premenopausal women (4.40 ± 1.75 v.s 4.06 ± 1.63 mg/dl, P < .01). Logistic regression analysis showed Body mass index (BMI) [OR = 1.08, P < .01]; and eGFR<60 vs.≥60 [OR = 1.22, P = .04] were independent risk factors for hypertension in women. Age and diabetes were independent risk factors for the participants with hypertension [OR = 1.04, P < .01] and [OR = 2.24, P < .01]. High quartile SUA group has increased the risk for hypertension in postmenopausal women [OR = 1.34, P = .048]. We found that postmenopausal women have high SUA compared to premenopausal women. The high SUA quartiles uric acid may be an independent risk for hypertension in postmenopausal women.

High Concentrations of Uric Acid and Angiotensin II Act Additively to Produce Endothelial Injury

Renin angiotensin (Ang) system (RAS) activation in metabolic syndrome (MS) patients is associated with elevated uric acid (UA) levels, resulting in endothelial system dysfunction. Our previous study demonstrated that excessive UA could cause endothelial injury through the aldose reductase (AR) pathway. This study is the first to show that a high concentration of Ang II in human umbilical vein endothelial cells (HUVECs) increases reactive oxygen species (ROS) components, including O₂^·- and H₂O₂, and further aggravates endothelial system injury induced by high UA (HUA). In a MS/hyperuricemia model, nitric oxide (NO) production was decreased, followed by a decrease in total antioxidant capacity (TAC), and the concentration of the endothelial injury marker von Willebrand factor (vWF) in the serum was increased. Treatment with catalase and polyethylene glycol covalently linked to superoxide dismutase (PEG-SOD) to individually remove H₂O₂ and O₂^·- or treatment with the AR inhibitor epalrestat decreased ROS and H₂O₂, increased NO levels and TAC, and reduced vWF release. Taken together, these data indicate that HUA and Ang II act additively to cause endothelial dysfunction via oxidative stress, and specific elimination of O₂^·- and H₂O₂ improves endothelial function. We provide theoretical evidence to prevent or delay endothelial injury caused by metabolic diseases.

Prevalence of hyperuricaemia in an Eastern Chinese population: a cross-sectional study

OBJECTIVES

In the past decade, China has been characterised by large-scale urbanisation as well as rapid economic growth. The aim of this study was to further investigate the prevalence of hyperuricaemia (HUA) in an Eastern Chinese population.

DESIGN

Cross-sectional study.

SETTING

Survey of Prevalence in East China of Metabolic Diseases and Risk Factors China study.

PARTICIPANTS

In this study, 12 770 residents from 22 sites in Eastern China were recruited. Finally, 9225 subjects were included.

MAIN OUTCOME MEASURES

The serum levels of uric acid (UA), fasting plasma glucose (FPG), glycated haemoglobin and other metabolic parameters were tested. Waist circumference, weight, height and blood pressure were also measured. Questionnaires regarding smoking, drinking, education were collected from the subjects. HUA was defined as serum UA >420 µmol/L for men and >360 µmol/L for women.

RESULTS

The prevalence of HUA in this Eastern Chinese population was 11.3% (9.9, 12.7) overall, 20.7% (17.7, 23.7) in men and 5.6% (4.3, 6.7) in women. The prevalence of HUA in urban subjects was higher than that in rural subjects (12.9 vs 10.8%, p<0.01). The prevalence of HUA was negatively and positively associated with age in men and women, respectively. Residents with high body mass index levels had a higher prevalence of HUA. In the logistic regression analysis, male sex, urban residency, total cholesterol, triglyceride, overweight, obesity, systolic blood pressure and low economic status were independently correlated with HUA.

CONCLUSIONS

The estimated prevalence of HUA in this Eastern Chinese population was 11.3% (9.9, 12.7) overall and 20.7% (17.7, 23.7) and 5.6% (4.3, 6.7) in men and women, respectively. HUA has gradually become an important public health issue in China.

TRIAL REGISTRATION NUMBER

ChiCTR-ECS-14005052.

The relationship between elevated serum uric acid and arterial stiffness in a healthy population

OBJECTIVE

This study aims to investigate the relationship between serum uric acid and arterial stiffness in a healthy population.

METHODS

Among the 979 participants, baPWV was non-invasively measured, the circulating levels of uric acid were tested, and the uric acid polymorphisms (rs2231142 and rs11722228) were genotyped. Then, the Mendelian randomization method was employed to test the relationship between serum uric acid and arterial stiffness in a healthy population.

RESULTS

After adjusting for age, gender, antihypertensive medication, body mass index, waist-to-hip ratio, urea nitrogen, creatinine and diabetic mellitus, there was a significant allelic difference in uric acid levels for each genotype (P < 0.0001 for rs2231142; P = 0.007 for rs11722228). However, there were no differences on the potential confounders between the genotypes of rs2231142 and rs11722228 (P > 0.05). The baPWV was significantly associated with circulating levels of uric acid after adjusting for cardiovascular risk factors and other potential confounders (P = 0.002). However, neither the single polymorphism, nor the accumulation of culprit alleles was associated with baPWV (P = 0.92 for rs2231142; P = 0.60 for rs11722228; P for trend = 0.77 for the combined analysis of culprit alleles).

CONCLUSION

These results do not support the causal role of circulating levels of uric acid in the development of arterial stiffness.

Association between uric acid and brachial-ankle pulse wave velocity: secondary analysis of data from a cross-sectional study

At present, the association between uric acid (UA) and brachial-ankle pulse wave velocity (baPWV) has not been well clarified. This study is the second analysis based on a cross-sectional study. 912 participants (average age is 51.5 ± 9.6 years) who underwent medical health examinations were included in this study, UA levels and baPWV were measured. Participants were divided into four groups according to UA levels (Quantile 1: 2.00-4.10 mg/dL; Quantile 2: 4.20-5.20 mg/dL; Quantile 3: 5.30-6.00 mg/dL and Quantile 4: 6.10-9.80 mg/dL), and the differences of baPWV between the four groups were compared. Univariate analysis showed a positive correlation between UA and baPWV [(Quantile 2 vs Quantile 1: 8.85 (-36.05, 53.75); Quantile 3 vs Quantile 1: 60.32 (13.22, 107.42) and Quantile 4 vs Quantile 1: 80.34 (36.19, 124.49)]. After adjusting for confounding factors, the positive correlation between UA and baPWV still exists [(Quantile 2 vs Quantile 1: -9.92 (-60.16, 40.32); Quantile 3 vs Quantile 1: 82.34 (4.00, 160.68) and Quantile 4 vs Quantile 1: 143.13 (0.75, 285.51)]. Furthermore, curve fitting showed that UA and baPWV had a non-linear positive correlation. In conclusion, elevated UA were associated with baPWV, suggesting that UA could be used as a predictor of atherosclerosis.

Uric Acid and Arterial Stiffness

Hyperuricemia is usually associated with hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Accumulating data from epidemiological studies indicate an association of increased uric acid (UA) with cardiovascular diseases. Possible pathogenic mechanisms include enhancement of oxidative stress and systemic inflammation caused by hyperuricemia. Arterial stiffness may be one of the possible pathways between hyperuricemia and cardiovascular disease, but a clear relationship between increased UA and vascular alterations has not been confirmed. The review summarizes the epidemiological studies investigating the relationship between UA and arterial stiffness and highlights the results of interventional studies evaluating arterial stiffness parameters in patients treated with UA-lowering drugs.

Uric acid association with pulsatile and steady components of central and peripheral blood pressures

OBJECTIVE

Whether the cardiovascular risk attributed to elevated uric acid levels may be explained by changes in central and peripheral pulsatile and/or steady blood pressure (BP) components remains controversial.

METHODS

In a cross-sectional analysis of normotensive and untreated hypertensive participants of the CARTaGENE populational cohort, we examined the relationship between uric acid, and both pulsatile and steady components of peripheral and central BP, using sex-stratified linear regressions.

RESULTS

Of the 20 004 participants, 10 161 individuals without antihypertensive or uric acid-lowering drugs had valid pulse wave analysis and serum uric acid levels. In multivariate analysis, pulsatile components of BP were not associated with uric acid levels, whereas steady components [mean BP (MBP), peripheral and central DBP] were all associated with higher levels of uric acid levels in women and men (all P < 0.001). Furthermore, there was a gradual increase of central SBP (cSBP), DBP and MBP from the lowest to the highest quintiles of uric acid levels but not for MBP-adjusted cSBP. Peripheral and cSBP, which are aggregate measures of pulsatile and steady BP, were also associated with uric acid levels in women (β = 0.063 and 0.072, respectively, both P < 0.001) and men (β = 0.043 and 0.051, both P ≤ 0.003). After further adjustments for MBP to account for the concomitant increase in steady component of BP, SBPs were no longer associated with uric acid levels.

CONCLUSION

Serum uric acid levels appear to be associated with both central and peripheral steady but not pulsatile BP, regardless of sex.

Association between serum uric acid and arterial stiffness in a low-risk, middle-aged, large Korean population: A cross-sectional study

We investigated the association between serum uric acid (SUA) and brachial ankle pulse wave velocity (baPWV) in an apparently healthy population. We performed a cross-sectional study on middle-aged Koreans who completed a yearly health-screening program between January and December 2014. Subjects with coronary artery disease, diabetes, or hypertension were excluded. Linear regression analyses were used to study the relationship between SUA and baPWV. Multiple adjustments were made for variables based on clinical or statistical significance. Of 66,917 study participants (38,170 men and 28,747 women), the mean age was 39.4 ± 6.7 years and the average SUA level was 5.23 ± 1.4 mg/dL. SUA values were higher in men than in women (6.1 ± 1.2 mg/dL vs. 4.1 ± 0.8 mg/dL). SUA was linearly associated with baPWV in women and in men (P < .001, respectively). Multiple regression analyses remained significant for women with a positive association with baPWV across SUA quintiles in a dose-response manner (P < .001) while no longer for men with a J-shaped association between SUA quintiles and baPWV. When SUA modeled continuously, baPWV rose by 12.413 cm/s in women (P < .001) and by 6.588 cm/s in men (P < .001) for each 1 mg/dL increase of SUA. In a low-risk, middle-aged, large Korean population, higher SUA levels could have an unfavorable impact on arterial stiffness as measured by baPWV, and this association was stronger in women than in men.

Uric acid and blood pressure: exploring the role of uric acid production in The Maastricht Study

OBJECTIVE

Accumulation of reactive oxygen species by increased uric acid production has been suggested as a possible underlying mechanism for the association between uric acid and high blood pressure (BP). We, therefore, investigated the association between serum uric acid concentration and 24-h urinary uric acid excretion, as proxy for uric acid production, with ambulatory 24-h blood pressure and hypertension.

METHODS

Cross-sectional analyses were conducted among 2555 individuals [52% men, mean age 60.0 ± 8.2 years; 27% type 2 diabetes (by design)] from The Maastricht Study. Multivariable regression analyses were performed to investigate the association of serum uric acid and 24-h urinary uric acid excretion with 24-h pulse pressure, 24-h mean arterial pressure (MAP), and hypertension.

RESULTS

After adjustment for traditional hypertension risk factors, serum uric acid concentration (per SD of 81 μmol/l) was associated with higher 24-h MAP [β 0.63 mmHg; confidence interval (CI) 0.27-1.00] and positively associated with hypertension (odds ratio 1.43; CI 1.27-1.61). Urinary uric acid excretion (per SD of 140 mg/day/1.73 m) was associated with higher 24-h MAP (β 0.79 mmHg; CI 0.46-1.12) and with hypertension (odds ratio 1.13; CI 1.02-1.25). There was no significant association between serum and 24-h urinary uric acid excretion with 24-h pulse pressure. There was no interaction with sex or age for the aforementioned associations.

CONCLUSION

Higher serum and urinary uric acid concentrations were associated with higher 24-h MAP and hypertension. These results suggest that serum and 24-urinary uric acid concentrations, the latter as proxy for uric acid production are, independent of each other, associated with BP and hypertension.

Gender-related association between uric acid, homocysteine, γ-glutamyltransferase, inflammatory biomarkers and metabolic syndrome in subjects affected by obesity

AIM

Evaluation of gender-related differences in uric acid (UA), homocysteine and inflammatory biomarkers as metabolic syndrome (MetS) determinants.

PATIENTS & METHODS

Anthropometric and routine data were obtained from 825 obese subjects (591 F, mean age 54 ± 14 years).

RESULTS

Hyperuricemia was 24% in both genders. Waist circumference, creatinine, triglycerides, C-reactive protein and γ-glutamyltransferase were identified as UA-independent determinants in females and creatinine and insulin in males. Hyperuricemia increased MetS risk in both genders (2.8-fold and 1.5-fold in males and females).

CONCLUSION

UA and γ-glutamyltransferase positively relate to MetS in both genders, although inflammatory abnormalities are closer related to UA and MetS in females. These differences in gender physiology may account for epidemiologic gender disparities and help to develop gender-targeted clinical strategies.

Uric Acid Level Has a U-shaped Association with Clinical Outcomes in Patients with Vasospastic Angina

No data are available on the association of serum uric acid and vasospastic angina (VSA) which has endothelial dysfunction as a possible pathophysiologic mechanism. Low uric acid level might cause adverse outcomes in VSA in connection with endothelial dysfunction. We enrolled 818 VSA patients whose uric acid level was measured at admission. Patients were categorized according to tertiles of uric acid level: group I, ≤ 4.8 mg/dL; group II, 4.9-5.9 mg/dL; and group III, ≥ 6.0 mg/dL. Primary outcome was major adverse cardiac events (MACEs), defined as a composite of cardiac death, acute myocardial infarction (MI), ischemic stroke, coronary revascularization, and rehospitalization for angina. Median follow-up duration was 49.2 months. Median uric acid values were 4.1 mg/dL for group I, 5.4 mg/dL for group II, and 6.7 mg/dL for group III. In the overall population, group II had a significantly lower incidence of MACE compared to group I (47 [17.1%] vs. 66 [24.6%]; hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.02-2.26; P = 0.040) and a tendency of lower incidence of MACEs compared to Group III (47 [17.1%] vs. 62 [22.5%]; HR, 1.44; 95% CI, 0.98-2.13; P = 0.067). Among group I patients, those who received nitrates had a higher incidence of MACEs than those without nitrate therapy (P < 0.001). Low uric acid level was associated with adverse clinical outcomes, while high uric acid level had a trend toward an increase in it. Use of nitrate in patients with low uric acid level might have adverse effects on clinical outcomes of VSA.

Visceral fat mass: is it the link between uric acid and diabetes risk?

BACKGROUND

Uric acid (UA) has been suggested as a novel risk factor for diabetes. However, its definite role in this prevalent disease is still the subject of much discussion because it is always accompanied with other major risk factors such as obesity and high visceral adiposity. In order to clarify the role of UA in diabetes, this study aimed to investigate the associations between plasma UA and fasting plasma glucose, HbA1c, lipid profile and inflammatory markers after accounting for the contribution of other diabetes risk factors such as BMI and VAT fat mass.

METHODS

In the present cross-sectional study, 100 non-diabetic middle-aged males (n = 48) and females (n = 52) were recruited. Central fat distribution measures including android to gynoid fat ratio, VAT and subcutaneous adipose tissue (SAT) fat mass were determined using dual-energy X-ray absorptiometry (DXA). Biochemical analysis was done using methods well established for clinical and research laboratories. Multiple linear regression analysis was performed to analyse the association between plasma UA and the biochemical and central fat distribution measures.

RESULTS

UA was positivly associated with body mass index (BMI) (r (98) = 0.42, P ≤ 0.001), android to gynoid fat ratio (r (98) = 0.62, P ≤ 0.001) and VAT fat mass (r (96) = 0.55, P ≤ 0.001). UA was also positively associated with plasma glucose (r (98) = 0.33, P ≤ 0.001), hemoglobin A1c (r (93) = 0.25, P = 0.014), plasma triglyceride (r _s (95) = 0.40, P ≤ 0.001), HDL cholesterol (r (98) = - 0.61, P ≤ 0.001) and CRP (r _s (98) = 0.23, P = 0.026). However, these associations were no longer significant after accounting for BMI or/and VAT fat mass. No significant association was observed between UA and SAT fat mass (r (97) = 0.02, P ≥ 0.05), Total cholesterol (r (98) = 0.03, P ≥ 0.05), LDL cholesterol (r (98) = 0.13, P ≥ 0.05), TNF-α (r (97) = 0.12, P ≥ 0.05) and IL-6 (r (96) = -0.02, P ≥ 0.05).

CONCLUSION

Results from this study suggest, for the first time, that the association between plasma UA and glucose in a non-diabetic population is not direct but rather dependent on VAT fat mass.

Does the serum uric acid level have any relation to arterial stiffness or blood pressure in adults with congenital renal agenesis and/or hypoplasia?

BACKGROUND

The relationship between serum uric acid and arterial stiffness or blood pressure is not clear. The serum uric acid level and its association with cardiovascular risk is not well known in patients with reduced renal mass. We aimed to investigate the relation between serum uric acid levels and arterial stiffness and also blood pressure in patients with congenital renal agenesis and/or hypoplasia.

MATERIAL AND METHODS

In this single center, cross-sectional study, a total of 55 patients (39 (% 70.9) with unilateral small kidney and 16 (%29.1) with renal agenesis) were included. The median age was 35 (21-50) years. The study population was divided into tertiles of serum uric acid (according to 2.40-3.96, 3.97-5.10, and 5.11-9.80 mg/dl cut-off values of serum uric acid levels). Official and 24-h ambulatory non-invasive blood pressures of all patients were measured. The arterial stiffness was assessed by pulse wave velocity (PWV).

RESULTS

PWV values were increased from first to third tertile (5.5 ± 0.6, 5.7 ± 0.8, 6.1 ± 0.7, respectively), but this gradual increase between tertiles did not reach significance. Linear regression analyses showed a positive correlation between serum uric acid levels and PWV (β = 0.40, p = 0.010), but no correlation was found between uric acid and daytime systolic blood pressure (β = 0.24, p = 0.345).

CONCLUSION

In congenital renal agenesis/hypoplasia, the serum uric acid level was positively correlated with arterial stiffness, but there was no correlation with blood pressure.

A higher baseline plasma uric acid level is an independent predictor of arterial stiffness: A community-based prospective study

Hyperuricemia has been demonstrated to be a risk factor for cardiovascular diseases. Though the association between uric acid (UA) and arterial stiffness has been investigated previously in patients with basic diseases, the predictive value of baseline UA level for arterial stiffness has not been conducted. We aimed at identifying the predictive role of UA for arterial stiffness prospectively.A longitudinal follow-up study in a routine health check-up population was performed with an average follow-up of 4.8 years. The demographic information, baseline and follow-up anthropometric parameters, arterial stiffness (pulse-wave velocity, PWV), and biomarker variables including UA have been measured and analyzed.A total of 1447 valid follow-ups were available for the final analysis. Both of the baseline and follow-up UA levels were significantly higher in the arterial stiffness groups than that in the nonarterial stiffness groups (all P values <0.001). The follow-up carotid-femoral PWV [(cf-PWV), r = 0.161, P < 0.001] was strongly correlated with baseline UA. At the follow-up cross-section, cf-PWV was also closely associated with UA (r = 0.101, P < 0.001). Logistic regressions revealed that a higher baseline UA level was an independent predictor of follow-up arterial stiffness assessed by cf-PWV [odds ratio (OR): 1.824; P = 0.046].A higher baseline level of UA is closely related to arterial stiffness and is an independent predictor of arterial stiffening.

Peripheral arterial stiffness is associated with higher baseline plasma uric acid: A prospective cohort study

This prospective cohort study aimed at identifying association between uric acid (UA) and peripheral arterial stiffness. A prospective cohort longitudinal study was performed according to an average of 4.8 years’ follow-up. The demographic data, anthropometric parameters, peripheral arterial stiffness (carotid-radial pulse-wave velocity, cr-PWV) and biomarker variables including UA were examined at both baseline and follow-up. Pearson’s correlations were used to identify the associations between UA and peripheral arterial stiffness. Further logistic regressions were employed to determine the associations between UA and arterial stiffness. At the end of follow-up, 1447 subjects were included in the analyses. At baseline, cr-PWV (r = 0.200, p < 0.001) was closely associated with UA. Furthermore, the follow-up cr-PWV (r = 0.145, p < 0.001) was also strongly correlated to baseline UA in Pearson’s correlation analysis. Multiple regressions also indicated the association between follow-up cr-PWV (β = 0.493, p = 0.013) and baseline UA level. Logistic regressions revealed that higher baseline UA level was an independent predictor of arterial stiffness severity assessed by cr-PWV at follow-up cross-section. Peripheral arterial stiffness is closely associated with higher baseline UA level. Furthermore, a higher baseline UA level is an independent risk factor and predictor for peripheral arterial stiffness.

Uric Acid, Vascular Stiffness, and Chronic Kidney Disease: Is There a Link?

Controversy exists with regard to the causal role of hyperuricemia in chronic kidney disease. Vascular stiffness may be the link that explains the relation between hyperuricemia and kidney disease. Hyperuricemia is associated with a number of effects on the vascular endothelium and vascular smooth muscle cells, including an increase in oxidative stress, production of vasoconstrictors, and changes on the structural properties of the large artery wall. Observational evidence in large epidemiological cross-sectional studies suggests that there is an independent association between uric acid and arterial stiffness. The limited evidence from cohort studies or clinical trials does not support treatment of hyperuricemia to reduce vascular stiffness in order to prevent kidney disease. Nevertheless, vascular stiffness may be a valid, reproducible, and useful surrogate endpoint. At this point there seems to be sufficient evidence to warrant larger clinical trials to determine whether lowering uric acid concentrations would be useful for prevention or treatment of vascular stiffness and, subsequently, of cardiovascular and kidney diseases. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=452726.

Association between Sex Hormone and Blood Uric Acid in Male Patients with Type 2 Diabetes

The association between serum uric acid (SUA) level and sexual dysfunction in patients with diabetes is not well characterized. Type 2 diabetes mellitus (T2DM) causes metabolic disorders, including abnormal serum uric acid (SUA) levels. In this study, we enrolled 205 male patients with T2DM and investigated the relationship between sex hormone levels and SUA. Patients were divided into four groups based on SUA quartiles. On the other hand, based on the total testosterone (TT) level, patients were divided into three groups; SUA and other laboratory indices were determined. Increase in SUA level was significantly associated with decreased levels of TT, luteinizing hormone, follicle-stimulating hormone, sex hormone-binding globulin, and increased levels of dehydroepiandrosterone, age, body mass index (BMI), waist circumference, glycated hemoglobin, serum creatinine, and HOMA-IR levels. SUA, waist circumference, BMI, and HOMA-IR showed a negative correlation with TT level, while age showed a positive correlation with TT level. SUA and body mass index were found to be risk factors for gonadal dysfunction. Therefore, we conclude that hypogonadism of male patients with T2DM is related to SUA level.

Association between serum uric acid (SUA) levels and metabolic syndrome (MetS) components in personnel of Shahroud University of Medical Sciences

AIMS

Serum uric acid level has been suggested to be associated with metabolic syndrome risk factors. However, the association between metabolic syndrome and serum uric acid is still controversial and challenging. This study was aimed to investigate the association between serum uric acid levels and metabolic syndrome components in personnel of the Shahroud University of Medical Sciences.

MATERIAL AND METHODS

This case-control study was conducted on 499 personnel aged 30-60 years old who were working in Shahroud University of Medical Sciences, in 2015. MetS was defined according to the National Cholesterol Education Program (NCEP) criteria. The relationship between serum UA level and the number of metabolic components was determined by linear regression analysis.

RESULT

In this study, the mean concentration of serum uric acid in men with the syndrome was higher than that in women. Mean serum UA level increased as the number of metabolic factors increased. The mean serum uric acid levels was 4.98±1.64 in patients with metabolic syndrome and 4.5±1.28 in non-patients (p=0.005). Subject with abnormal uric acid were almost 2.62 times more likely than other subject to develop the syndrome.

CONCLUSIONS

The results of this study showed that only hypertriglyceridemia is a component which increases the risk of hyperuricemia. In addition, hyperuricemia increases the risk of metabolic syndrome by more than two fold. It seems that high uric acid can be considered as a predisposing factor for metabolic syndrome; thus, it is recommended to measure serum uric acid in routine tests.

Association between serum uric acid level and metabolic syndrome components

Background

Serum uric acid levels is reported to be associated with a variety of cardiometabolic risk factors; however, its direct association with metabolic syndrome (MetS) remains controversial. Thus, we examined the association of serum uric acid concentrations with the MetS components.

Methods

MetS was defined according to the National Cholesterol Education Program (NCEP) criteria. This case–control study comprised 101 non-smoking individuals (41 in the MetS group and 60 in the non-MetS group). Blood pressure, fasting plasma glucose, insulin, HOMA-IR, lipid profiles, uric acid, and anthropometric measures were determined, and body composition was assessed by using bioelectrical impedance analysis (BIA).

Results

After adjustment for confounding factors, serum uric acid was significantly higher in MetS group than non-MetS group (5.70 ± 1.62 vs 4.97 ± 1.30 mg/dL, respectively, P = 0.001). After controlling for age, sex and body mass index in partial correlation analysis, uric acid was positively correlated with triglycerides, and negatively with HDL-C. In multiple logistic regression analysis, every 1 mg/dl elevation in the serum uric acid level increased the risk of MetS approximately by 2-folds (OR: 2.11, 95 % CI: 1.30-3.41).

Conclusion

This study showed that those individuals with MetS have higher uric acid levels; the association of uric acid and MetS components supports that it might be an additional components of MetS.

Serum Uric Acid and Pulse Wave Velocity Among Healthy Adults: Baseline Data From the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND

We aimed to evaluate a possible association between serum uric acid (SUA) levels and carotid-to-femoral pulse wave velocity (cf-PWV) among healthy participants of the ELSA-Brasil.

METHODS

We excluded subjects using antihypertensive medication, diuretics, allopurinol, binge drinkers, body mass index (BMI) >35 kg/m2, and those with history of cardiovascular diseases (CVD). In a cross-sectional and sex-specific analysis, linear regression models were built having cf-PWV as dependent variable and SUA as independent variable. Multiple adjustments were subsequently made for age, heart rate and blood pressure, BMI, and fasting glucose levels as covariates. Product interaction terms were built to test interaction between SUA and other covariates.

RESULTS

We analyzed 1,875 men and 1,713 women (mean ages, 48.9±8.4 and 50.2±8.7 years, respectively). SUA was linearly associated with cf-PWV in men (P = 0.01) and in women (P = 0.01). After full adjustment, the association remained significant for men (P = 0.01) and no longer significant for women (P = 0.10). Fully adjusted linear coefficients β (95% CI) were 0.06 (0.015; 0.112) and 0.04 (-0.01; 0.12) in men and women, respectively. Significant interaction between SUA and age (P = 0.02) fasting glucose (P < 0.01) and BMI (P = 0.02) was found only for women.

CONCLUSION

In an apparently healthy population, SUA was significantly associated to cf-PWV in men but not in women.

Association of Uric Acid With Vascular Stiffness in the Framingham Heart Study

BACKGROUND

Uric acid is associated with increased risk of cardiovascular disease and arterial stiffness in patients with hypertension or stroke. It remains unknown if uric acid is associated with arterial stiffness in the general population.

METHODS

We analyzed the association between serum uric acid levels and measures of arterial stiffness such as carotid-femoral pulse wave velocity (CF PWV), carotid-radial pulse wave velocity (CR PWV) and augmentation index (AI) in 4,140 participants from the Generation 3 Framingham cohort using linear regression.

RESULTS

Mean (SD) age was 40.0 (8.8) years and mean (SD) serum uric acid levels were 5.3 (1.5) mg/dl. Mean (SD) CF PWV was 7.0 (1.4) m/s. Individuals in the highest quartile of uric acid were more likely to be male, have a higher prevalence of hypertension, higher BMI, fasting glucose and insulin, and lower estimated glomerular filtration rate (eGFR). Multivariate adjusted means of CF PWV were 6.90, 6.94, 7.06, and 7.15 m/s for uric acid quartile 1, 2, 3, and 4 respectively. In unadjusted analysis each 1mg/dl increase in uric acid was associated with higher CF-PWV (β = 0.27; 95% CI = 0.25, 0.29; P < 0.0001). This was attenuated but remained significant after adjusting for age, sex, smoking, hypertension, BMI, fasting glucose, insulin, animal protein intake, and eGFR (β= 0.06; 95% CI = 0.02, 0.09; P < 0.0007). There was no association between serum uric acid levels and AI upon adjustment for cardiovascular risk factors.

CONCLUSIONS

Serum uric acid levels are significantly associated with CF PWV and CR PWV in a younger Caucasian population.

Multimarker Analysis for New Biomarkers in Relation to Central Arterial Stiffness and Hemodynamics in a Chinese Community-Dwelling Population

Central arterial stiffness and hemodynamics independently reflect the risk of cardiovascular events. This Chinese community-based analysis was performed to evaluate the relationships of new biomarkers with central arterial stiffness and hemodynamics by a multimarker method. This analysis consisted of 1540 participants who were fully tested for the new biomarkers including N-terminal prohormone of brain natriuretic peptide, lipid accumulation product, triglyceride-high-density lipoprotein cholesterol (TG-HDL-c) ratio, uric acid, high-sensitivity C-reactive protein, and homocysteine. Carotid-femoral pulse wave velocity (cfPWV), central pulse pressure (cPP), and central augmentation index (cAIx) were measured. The median (range) age of entire cohort was 62 years (21-96 years), and 40.5% were males. The median (interquartile range) of cfPWV, cPP, and cAIx was 11.0 m/s (9.6-13.0 m/s), 42 mm Hg (35-52 mm Hg), and 28% (21%-33%), respectively. In multivariate analysis, participants with higher cfPWV had significantly higher age, peripheral pulse pressure, TG, TG-HDL-c ratio, and homocysteine levels compared with others (P < .05 for all). Multimarker analysis in a Chinese community-dwelling population reinforced the potential clinical value of plasma TG-HDL-c ratio and homocysteine levels as the biomarkers of increased arterial stiffness.

The association of metabolic syndrome and its components with brachial-ankle pulse wave velocity in south China

BACKGROUND

Brachial-ankle pulse wave velocity (baPWV) can reflect both central and peripheral arterial stiffness. Metabolic syndrome (MS) and its components may increase arterial stiffness and the risks of cardiovascular diseases. However, the correlation of MS and its components with arterial stiffness has not been not well studied. The aim of this study was to investigate the correlation between MS/its components and arterial stiffness by the measurement of baPWV in south China population.

METHODS

A total of 8599 subjects were selected from those who underwent health examination in our hospital. MS was defined by Joint Scientific Statement. BaPWV, waist circumference, blood pressure (BP), fasting plasma glucose (FPG), lipid profile and serum uric acid (UA) were measured. The relationship between baPWV and MS/its components was analyzed.

RESULTS

BaPWV was significantly higher in the subjects with MS than in those without MS (P < 0.001 for both genders). By multivariate regression analysis, all the metabolic components were correlated to baPWV in the male and female subjects except low HDL-C and high UA in the male group. BP and FPG had the strongest correlation factors. The values of baPWV were positively correlated with the advanced age (P < 0.001) and the values of the MS components, and this correlation was stronger in the females than in the males (P < 0.001).

CONCLUSION

Metabolic syndrome and its individual components were positively correlated with baPWV. Monitoring baPWV is helpful to identify early stage of arterial stiffness in those people with MS.

Association of hyperuricemia with conventional cardiovascular risk factors in elderly patients

The relationship between serum uric acid (UA) and cardiovascular risk profile was investigated in 557 outpatients (415 women) aged 60 years and older. Patients were grouped according to a UA cutoff level of 5.5 mg/dL. Prevalence of obesity, hypertension, and impaired glucose metabolism was increased in women with higher UA, who had higher body mass index (37.7±6.9 vs 33.1±5.9 kg/m(2) , P<.001), waist circumference, and serum glucose and triglyceride concentrations than women with lower UA levels. Conversely, men with higher UA levels showed lower high-density lipoprotein cholesterol and higher left ventricular mass than men with lower UA levels. Estimated glomerular filtration rate was reduced in patients with high UA levels of both sexes (65±17 vs 72±16 mL/min/1.73 m(2) , P<.001, for women; 70±16 vs 76±15 mL/min/1.73 m(2) , P<.03, for men). Grouping patients by sex-specific median UA concentrations produced similar results. These data indicate that, even in the elderly, UA clusters in a sex-specific fashion with features of metabolic syndrome and signs of target organ damage.

Serum uric acid and its relationship with metabolic syndrome and cardiovascular risk profile in patients with hypertension: insights from the I-DEMAND study

BACKGROUND AND AIMS

The independent role of serum uric acid (SUA) as a marker of cardio-renal risk is debated. The aim of this study was to assess the relationship between SUA, metabolic syndrome (MS), and other cardiovascular (CV) risk factors in an Italian population of hypertensive patients with a high prevalence of diabetes.

METHODS AND RESULTS

A total of 2429 patients (mean age 62 ± 11 years) among those enrolled in the I-DEMAND study were stratified on the basis of SUA gender specific quartiles. MS was defined according to the NCEP-ATP III criteria, chronic kidney disease (CKD) as an estimated GFR (CKD-Epi) <60 ml/min/1.73 m(2) or as the presence of microalbuminuria (albumin-to-creatinine ratio ≥2.5 mg/mmol in men and ≥3.5 mg/mmol in women). The prevalence of MS, CKD, and positive history for CV events was 72%, 43%, and 20%, respectively. SUA levels correlated with the presence of MS, its components, signs of renal damage and worse CV risk profile. Multivariate logistic regression analysis revealed that SUA was associated with a positive history of CV events and high Framingham risk score even after adjusting for MS and its components (OR 1.10, 95% CI 1.03-1.18; P = 0.0060; OR 1.28, 95% CI 1.15-1.42; P < 0.0001). These associations were stronger in patients without diabetes and with normal renal function.

CONCLUSIONS

Mild hyperuricemia is a strong, independent marker of MS and high cardio-renal risk profile in hypertensive patients under specialist care. Intervention trials are needed to investigate whether the reduction of SUA levels favorably impacts outcome in patients at high CV risk.

Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Association of uric acid with metabolic syndrome in men, premenopausal women and postmenopausal women

OBJECTIVE

To explore the relationship between serum uric acid (SUA) and metabolic syndrome (MS) in men, premenopausal women and postmenopausal women.

METHODS

A cross-sectional study was conducted in 1,834 community-based Southern Chinese participants from June to October 2012. Sex-specific SUA quartiles were used as follows: <345, 345-<400, 400-<468, ≥ 468 µmol/L in males; and <248, 248-<288, 288-<328, ≥ 328 µmol/L in females. MS was defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) Criteria. The association between SUA and MS was then analyzed using the STATA software.

RESULTS

The odds ratio (OR) for having MS in the highest versus lowest quartiles of SUA levels was 2.46 (95% confidence interval [CI], 1.39 to 4.34, p = 0.002) in men after adjusting for age, sex, history of coronary heart disease, history of stroke, current current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.06 (95% CI, 1.64 to 5.70, p < 0.001). The OR for having MS in the highest versus lowest quartiles of SUA was 3.45 (95% CI, 1.38 to 8.64, p = 0.008) and 1.98 (95% CI, 1.16 to 3.37, p = 0.08) in premenopausal women and postmenopausal women after adjusting for age, sex, history of coronary heart disease, history of stroke, current smoking, current alcohol use, physical inactivity, education status, and BMI. Further adjusting for above confounders, hypertension and diabetes, the OR for having MS in the highest versus lowest quartiles of SUA was 3.42 (95% CI, 1.15 to 10.18, p = 0.03) and 1.87 (95% CI, 1.05 to 3.33, p = 0.03) in premenopausal women and postmenopausal women.

CONCLUSIONS

Higher SUA levels are positively associated with the presence of MS in males and females. Higher SUA levels had a higher risk of having MS in premenopausal women than in postmenopausal women.

High sodium intake in women with metabolic syndrome

Background and Objectives

Metabolic syndrome and high sodium intake are associated with frequent cardiovascular events. Few studies have estimated sodium intake in subjects with metabolic syndrome by 24-hour urine sodium excretion. We evaluated sodium intake in individuals with metabolic syndrome.

Subjects and Methods

Participants were recruited by random selection and through advertisement. Twenty four-hour urine collection, ambulatory blood pressure measurements, and blood test were performed. Sodium intake was estimated by 24-hour urine sodium excretion. Participants receiving antihypertensive medications were excluded from analysis.

Results

Among the 463 participants recruited, subjects with metabolic syndrome had higher levels of 24-hour urine sodium excretion than subjects without metabolic syndrome (p=0.0001). There was a significant relationship between the number of metabolic syndrome factors and 24-hour urine sodium excretion (p=0.001). The proportion of subjects with metabolic syndrome was increased across the tertile groups of 24-hour urine sodium excretion (p<0.0001). The association of high sodium intake and metabolic syndrome was significant only among women. Among the factors related to metabolic syndrome, body mass index had an independent association with 24-hour urine sodium excretion (p<0.0001).

Conclusion

Women with metabolic syndrome exhibited significantly higher sodium intake, suggesting that dietary education to reduce sodium consumption should be emphasized for women with metabolic syndrome.

Metabolic syndrome, diabetes, and hyperuricemia

PURPOSE OF REVIEW

To explore the causal relationship between metabolic syndrome, type 2 diabetes and hyperuricemia.

RECENT FINDINGS

The prevalence of hyperuricemia in male adults with metabolic syndrome was increased and a large difference in prevalence of metabolic syndrome also existed in those with hyperuricemia compared with normouricemia. Even in those with normouricemia, higher serum uric acid levels were associated with metabolic syndrome. Serum uric acid was an independent risk factor for incident diabetes, and evidence showed that the patients with both gout and type 2 diabetes exhibited a mutual inter-dependent effect on higher incidences. Furthermore, obese patients often demonstrated insulin resistance and adipose tissue macrophage with low-grade inflammation, which is suggested to be the major contributor. Although alcohol intake is considered a risk for developing hyperuricemia, moderate alcohol intake showed a lower risk for developing type 2 diabetes and insulin resistance. Hyperinsulinemia reduces renal excretion of uric acid on the proximal tubular of the kidney leading to hyperuricemia, which has deleterious effects on endothelial function and on nitric oxide bioavailability, thus causing hyperinsulinemia.

SUMMARY

We found evidence to suggest that insulin resistance plays a potentially key role in the causal relationship between metabolic syndrome, type 2 diabetes and hyperuricemia. Furthermore, it is likely that hyperuricemia and insulin resistance share a bidirectional causal effect.

Relationship between uric acid and vascular structure and function in hypertensive patients and sex-related differences

BACKGROUND

We sought to analyze the relationship between uric acid (UA) and vascular structure and function based on the carotid intima-media thickness, the pulse-wave velocity (PWV), the central arterial pressure, and the augmentation index in hypertensive patients and to evaluate the sex-related differences.

METHODS

A cross-sectional study was performed with 366 hypertensive individuals aged 34-75 years (men = 61.74%). The vascular structure was assessed based on the carotid intima-media thickness, the arterial stiffness was assessed by PWV, and the vascular function was assessed using hemodynamic parameters such as the central and peripheral augmentation index and the ambulatory arterial stiffness index (AASI).

RESULTS

In the bivariable analysis, the PWV (r = 0.28; P < 0.01) and AASI (r = 0.25; P < 0.01) were positively correlated with UA in women. The central augmentation index (r = -0.16; P < 0.05) and peripheral augmentation index (r = -0.18; P < 0.05) were negatively correlated with UA, whereas the maximum carotid intima-media thickness (r = 0.11; P < 0.05) was positively correlated with UA in the global analysis. In the multiple linear regression analysis, a positive association between PWV and UA was observed after adjusting for classical risk factors (β = 0.27; P = 0.01) in women only. In turn, a negative association was observed between the AASI and UA after adjusting for confounders in men (β = -0.06; P = 0.04), with a positive association in women (β = 0.11; P = 0.03).

CONCLUSIONS

Serum UA showed a positive correlation with the mean maximum intima-media thickness and PWV, and this parameter showed a negative correlation with the central and peripheral augmentation indices, although this relationship was lost after adjusting for confounding factors. AASI showed a positive association in women and a negative association in men after adjusting for confounding factors.

CLINICAL TRIALS REGISTRATION

Clinical Trials.gov Identifier: NCT01325064.

The Impacts of Serum Uric Acid on arterial hemodynamics and Cardiovascular Risks

Hyperuricemia, and its clinical manifestation gout, is a metabolic disease process that has been recognized since the dawn of medical inquiry. Uric acid was hypothesized to be a mediator of cardiovascular disease for period of time. Epidemiological correlations of hyperuricemia with hypertension and cardiovascular events were evident for two centuries' studies. With recent animal studies shedding light on the causal mechanisms of hypertension, and clinical trials suggesting that urate-lowering therapy can lower blood pressure, there appears to be growing evidence of a connection between hyperuricemia and cardiovascular disease. To help bring this recent uric acid research into context, we have undertaken this narrative review of hyperuricemia, hypertension, its hemodynamics and its outcomes, and the risk for cardiovascular diseases.

KEY WORDS

Cardiovascular risk; Hemodynamics; Uric acid.

Associations of serum uric acid levels with arterial wave reflections and central systolic blood pressure

BACKGROUND

Uric acid may be involved in the pathogenesis of hypertension. We investigated the roles of four major hemodynamic parameters of blood pressure, including arterial stiffness, wave reflections, cardiac output (CO), and total peripheral resistance (TPR), in the association between uric acid and central systolic blood pressure (SBP-c).

METHODS

A sample of 1303 normotensive and untreated hypertensive Taiwanese participants (595 women, aged 30-79 years) was drawn from a community-based survey. Study subjects' baseline characteristics, biochemical parameters, carotid-femoral pulse wave velocity (cf-PWV), amplitude of the backward pressure wave decomposed from a calibrated tonometry-derived carotid pressure waveform (Pb), CO, TPR, and SBP-c were analyzed.

RESULTS

In multi-variate analyses adjusted for age, waist circumference, body mass index, creatinine, total cholesterol, smoking, and heart rate, uric acid significantly correlated with Pb and cf-PWV in men, and Pb and TPR in women. The correlation between uric acid and Pb remained significant in men and women when cf-PWV was further adjusted. In the final multi-variate prediction model (model r(2)=0.839) for SBP-c, the significant independent variables included uric acid (partial r(2)=0.005), Pb (partial r(2)=0.651), cf-PWV (partial r(2)=0.005), CO (partial r(2)=0.062), TPR (partial r(2)=0.021), with adjustment for age, sex, waist circumference, body mass index, creatinine, total cholesterol, smoking, and heart rate.

CONCLUSIONS

Uric acid was significantly independently associated with wave reflections, which is the dominant determinant of SBP-c. Uric acid was also significantly associated with SBP-c independently of the major hemodynamic parameters.

Alkalizer administration improves renal function in hyperuricemia associated with obesity

We evaluated the combination effect of the alkalizer citrate with the xanthine oxidase inhibitor allopurinol on renal function and uric acid in patients with hyperuricemia associated with obesity and/or metabolic syndrome (MetS), who were extracted from among the subjects enrolled in a prospective randomized controlled study aimed at assessing the efficacy of such a combination for improving renal function. We also conducted a post hoc analysis to examine influences on lipid profiles.

Patients who consented to participate in the study were randomly allocated to receive either allopurinol alone (monotherapy) or in combination with a citrate preparation (combination therapy). The analysis population consisted of 31 obese patients with a body mass index greater than 25 kg/m² (monotherapy, 15 patients; combination therapy, 16 patients). The creatinine clearance rate (Ccr), serum uric acid levels, and lipid profiles were measured before and at 12 weeks after the start of treatment.

In the combination therapy group, Ccr increased significantly and serum uric acid levels decreased significantly in obese patients, while Ccr tended to increase and serum uric acid levels decreased, though not significantly, in patients with MetS-related clinical parameters. Overall, blood triglyceride levels tended to improve in the combination therapy group as compared with the monotherapy group.

Association between Uric Acid and Metabolic Syndrome in Qazvin Metabolic Diseases Study (QMDS), Iran

Background:

The prevalence of Metabolic Syndrome (MS) has been increasing worldwide. Although Uric Acid (UA) Levels are often increased in subjects with MS, it is still unclear whether uric acid plays a causal role for MS or is a marker. The purpose of this study was to examine the association between UA and the MS in Qazvin, Iran.

Methods:

529 men and 578 women aged 20 – 78 years attended in cross sectional study from September 2010 to April 2011 in Qazvin, Iran. The criteria proposed by new joint Interim societies (JIS) were applied for diagnosis of MS. Hyperuricemia was defined as UA ≥ 7 mg/dL in men and UA ≥ 6 mg/dL in women. Logistic regression analysis was performed to evaluate the relationship between UA quartiles and MS.

Results:

The prevalence of MS was found to be 39.3%. Prevalence of hyperuricemia was 8.4% in males and 4.1% in females (P=0.004). Mean UA level was higher in males than in females (P<0.001). UA levels increased significantly with an increasing number of MS components in both genders. Prevalence of MS increased across UA quartiles in females; however the increasing trend began from second quartile in males. Using the lowest quartile of UA level as a reference, there were no significant association between UA quartile groups and MS.

Conclusion:

This study showed that UA levels are not an appropriate predictor of MS in Iranian population. More longitudinal studies are necessary to confirm the role of UA in MS occurrence.

Relationships between serum uric acid, adiponectin and arterial stiffness in postmenopausal women

OBJECTIVES

Cardiovascular disease (CVD) is a leading cause of death in postmenopausal women. Elevated serum uric acid levels, hypoadiponectinemia and arterial stiffness are strongly associated with cardiovascular diseases. We investigated the relationships among uric acid, adiponectin and arterial stiffness in postmenopausal women.

STUDY DESIGN

9555 subjects who had the routine health check-ups, 841 postmenopausal women aged 50 years or older who had not had a menstrual period for more than 12 consecutive months were included in this study.

MAIN OUTCOME MEASURES

BMI, WC, and serum concentrations of uric acid, adiponectin, glucose, lipids (total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol) were measured. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Pulse wave velocity (PWV) was evaluated to assess arterial stiffness.

RESULTS

The subjects were stratified into three groups according to uric acid values. PWV values gradually increased and adiponectin level decreased with uric acid tertiles. Serum uric acid levels in postmenopausal women correlated significantly with age, BMI, WC, TG, HDL-C, insulin, HOMA-IR, adiponectin and PWV. Multiple regression analysis showed that WC (β=0.141, P<0.01), HOMA (β=0.137, P<0.01), adiponectin (β=-0.104, P<0.01), and PWV (β=0.129, P<0.01) were independently correlated with uric acid levels. In multiple logistic regression analysis after adjusting for risk factors, uric acid was a significant contributor to increased PWV.

CONCLUSIONS

These findings indicate that serum uric acid is independently associated with adiponectin and arterial stiffness in postmenopausal women.

Serum uric Acid level and diverse impacts on regional arterial stiffness and wave reflection

BACKGROUND

Both increased arterial stiffness and hyperuricaemia are associated with elevated cardiovascular risks. Little is known about the relations of serum uric acid (UA) level to regional arterial stiffness and wave reflection. The aim of the study was to investigate the gender-specific association of serum UA and indices of arterial function in a community-based investigation in China.

METHODS

Cross-sectional data from 2374 adults (mean age 58.24 years) who underwent routine laboratory tests, regional pulse wave velocity (PWV) and pulse wave analysis measurements were analyzed in a gender-specific manner. None of the participants had atherosclerotic cardiovascular disease, chronic renal failure, systemic inflammatory disease, gout, or were under treatment which would affect serum UA level.

RESULTS

Men had higher serum UA level than women. Subjects with hyperuricaemia had significantly higher carotid-ankle PWV in both genders (P< 0.05), and the carotid-femoral PWV (PWVc-f) was higher in women (P< 0.001) while the augmentation index was marginally lower in men (P = 0.049). Multiple regression analysis showed that serum UA was an independent determinant only for PWVc-f in women (β = 0.104, P = 0.027) when adjusted for atherogenic confounders. No other independent relationship was found between UA level and other surrogates of arterial stiffness.

CONCLUSIONS

Serum UA levels are associated with alterations in systemic arterial stiffness that differ in men and women. Women might be more susceptible to large vascular damage associated with hyperuricaemia.

Significance of high-normal serum uric acid level as a risk factor for arterial stiffness in healthy Korean men

A high serum uric acid (SUA) level is a known risk factor for cardiovascular disease. However, little is known about the relationship between arterial stiffness and uric acid in healthy subjects with a normal SUA level. We assessed whether a high-normal uric acid level increased arterial stiffness by measuring brachial-ankle pulse wave velocity (ba-PWV) in healthy subjects. Among 779 subjects who visited the health promotion center, 393 men and 234 women with normal SUA levels (male: 3.5-8.0 mg/dl, female: 2.5-5.4 mg/dl) were divided into quartiles: in men, Q1 (n = 90, 3.5-4.3 mg/dl), Q2 (n = 94, 4.4-5.1 mg/dl), Q3 (n = 106, 5.2-5.9 mg/dl) and Q4 (n = 103, 6.0-8.0 mg/dl); in women, Q1 (n = 57, 2.5-3.6 mg/dl), Q2 (n = 49, 3.7-4.1 mg/dl), Q3 (n = 61, 4.2-4.6 mg/dl) and Q4 (n = 67, 4.7-5.4 mg/dl). The mean values of ba-PWV increased gradually by SUA quartile. The men's SUA had an independent, positive association with ba-PWV after correcting for age, glucose, body mass index, blood pressure, resting heart rate, high-sensitivity C-reactive protein (hs-CRP), high-density lipoprotein (HDL)-cholesterol and triglyceride (R (2) = 0.39, adjusted R (2) = 0.37, p < 0.001). The odds ratios (95% CI) for high ba-PWVs (> 75th percentile, 1473 cm/s) in men were 1.89 (0.69-5.20, Q2), 2.36 (1.10-5.08, Q3), and 2.91 (1.39-6.11, Q4), after adjusting for confounding factors (p < 0.001). In women, SUA showed no independent association with ba-PWV (p = 0.186). After adjusting for confounding factors, the mean ba-PWV values of Q3 (1418 cm/s) and Q4 (1421 cm/s) in men were higher than those of Q1 (1355 cm/s) (p < 0.05). Above the SUA level of 5.2 mg/dl, arterial stiffness was increased in healthy Korean men.

Association between serum uric acid level and metabolic syndrome

OBJECTIVES

Serum uric acid levels have been reported to be associated with a variety of cardiovascular conditions. However, the direct association between uric acid levels and metabolic syndrome remains controversial. Thus, we evaluated the association of serum uric acid levels and metabolic syndrome in a community-based cohort study in Korea.

METHODS

We performed cross-sectional analysis of baseline data of 889 males and 1491 females (aged 38 to 87) who participated in baseline examinations of the Korean Genome and Epidemiology Study: Kanghwa study. Blood samples were collected after at least an 8 hour fast. Uric acid quartiles were defined as follows: <4.8, 4.8-<5.6, 5.6-<6.5, ≥6.5 mg/dL in males; and <3.8, 3.8-<4.3, 4.3-<5.1, ≥5.1 mg/dL in females. Metabolic syndrome was defined by the National Cholesterol Education Program Adult Treatment Panel III Criteria with adjusted waist circumference cutoffs (90 cm for males; 80 cm for females). The association between serum uric acid quartiles and metabolic syndrome was assessed using multivariate logistic regression.

RESULTS

The odds ratio for having metabolic syndrome in the highest versus lowest quartiles of serum uric acid levels was 2.67 (95% confidence interval [CI], 1.60 to 4.46) in males and 2.14 (95% CI, 1.50 to 3.05) in females after adjusting for age, smoking, alcohol intake, body mass index, total cholesterol, HbA1c, albumin, γ-glutamyltransferase, blood urea nitrogen, and log C-reactive protein. The number of metabolic abnormalities also increased gradually with increasing serum uric acid levels (adjusted p for trend < 0.001 in both sexes).

CONCLUSIONS

Higher serum uric acid levels are positively associated with the presence of metabolic syndrome in Korean males and females.

Uric acid as one of the important factors in multifactorial disorders--facts and controversies

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.