Elevated uric acid and obesity-related cardiovascular disease risk factors among hypertensive youth

Skeptical Look at the Clinical Implication of Metabolic Syndrome in Childhood Obesity

Metabolic syndrome (MetS) is defined by a cluster of several cardio-metabolic risk factors, specifically visceral obesity, hypertension, dyslipidemia, and impaired glucose metabolism, which together increase risks of developing future cardiovascular disease (CVD) and type 2 diabetes mellitus (T2D). This article is a narrative review of the literature and a summary of the main observations, conclusions, and perspectives raised in the literature and the study projects of the Working Group of Childhood Obesity (WGChO) of the Italian Society of Paediatric Endocrinology and Diabetology (ISPED) on MetS in childhood obesity. Although there is an agreement on the distinctive features of MetS, no international diagnostic criteria in a pediatric population exist. Moreover, to date, the prevalence of MetS in childhood is not certain and thus the true value of diagnosis of MetS in youth as well as its clinical implications, is unclear. The aim of this narrative review is to summarize the pathogenesis and current role of MetS in children and adolescents with particular reference to applicability in clinical practice in childhood obesity.

Challenges in choosing the appropriate guidelines for use in children and adolescents with hypertension

BACKGROUND

This study was designed to observe the effect of antihypertensive treatment on blood pressure (BP) and target organ damage in patients followed up according to the American Academy of Pediatrics Hypertension Guidelines (AAPG). The results were also assessed in comparison with the definitions and target organ damage according to the European Society of Hypertension Guidelines 2016 (ESHG).

MATERIALS AND METHODS

A total of 44 (34 male) out of 140 patients were enrolled in the study and the mean age was 14±3.19years. The follow-up period was at least 12months. All patients underwent the following assessments: anthropometrical measurements of body mass index (BMI), left ventricular mass index (LVMI), and biochemical parameters according to the relevant guidelines. The pre-treatment and post-treatment datasets collected were compared.

RESULTS

The frequency of symptomatic patients decreased from 88% to 30%. After treatment, 29.4% (n=13) of patients still had elevated and stage 1 hypertension (HT) according to the AAPG. These patients were older and had higher BMI z-scores, LVMI z-scores, mean BP indices, and also had longer symptom duration than normotensive patients (P<0.001). When patients were assessed according to the ESHG, 34.1% (n=15) of patients had high-normal stage 1 and stage 2 HT. While 53.3% (n=8) of the patients aged 13-15years were classified as having high-normal stage 1 and stage 2 HT according to the ESHG, 33.3% (n=5) were classified as having elevated BP and stage 1 HT according to the AAPG. Additionally, 36.4% (n=4) of the patients aged≥16years were classified as having high-normal and stage 1 HT according to the ESHG, whereas 45.5% (n=5) were classified as having elevated BP and stage 1 HT according to the AAPG.

CONCLUSION

To control HT in children with higher BMI z-scores, higher LVMI z-scores, and higher BP indices, an earlier and more intensive approach is needed. Considering that the duration of exposure to HT may also affect the LVMI, adjusting age and gender or decreasing the current thresholds for LVMI may lead to an earlier diagnosis for more patients. According to the present classifications, the ESHG covers more children aged between 13 and 15years in contrast to the AAPG, which covers more patients aged≥16years. However, further studies are needed to confirm these results.

Impact of Pediatric Obesity on Diurnal Blood Pressure Assessment and Cardiovascular Risk Markers

Background: The prevalence of hypertension is increasing particularly among obese children and adolescents. Obese children and adolescents with hypertension are likely to remain hypertensive as they reach adulthood and hypertension is linked to an increased risk for cardiovascular disease. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has become one of the most important tools in diagnosing hypertension in children and adolescents and circadian patterns of blood pressure may be important disease-risk predictors. Methods: A retrospective chart review was conducted in patients aged 6-21 years who underwent 24-h ABPM at Kentucky Children's Hospital (KCH) from August 2012 through June 2017. Exclusion criteria included conditions that could affect blood pressure including chronic kidney disease and other renal abnormalities, congenital heart disease, cancer, and thyroid disease. Subjects were categorized by body mass index into normal (below 85th percentile), overweight (85th-95th percentile), stage I obesity (95th-119th percentile), stage II obesity (120th-139th) and stage III obesity (>140th). Non-dipping was defined as a nocturnal BP reduction of <10%. Results: Two hundred and sixty-three patients (156 male patients) were included in the analysis, of whom 70 were normal weight, 33 overweight, 55 stage I obesity, 53 stage II, and 52 stage III obesity. Although there was no significant difference between normal weight and obese groups for prevalence of hypertension, there was a greater prevalence of SBP non-dipping in obese patients as BMI increased (p = 0.008). Furthermore, non-dippers had a significantly elevated LVMI as well as abnormal lab values for uric acid, blood lipid panel, creatinine, and TSH (p < 0.05). Conclusions: These findings demonstrate that obese children and adolescents constitute a large proportion of hypertensive children and adolescents and the severity of pediatric obesity is associated with nocturnal BP non-dipping. Additionally, obesity in children is linked to several cardiovascular risk factors including left ventricular hypertrophy, dyslipidemia, and elevated uric acid levels. Further studies utilizing ABPM measures on risk stratification in this very high-risk population are warranted.

Identification of Cardiovascular Risk Factors in Obese Adolescents With Metabolic Syndrome

Objective: There are studies that show different associations between metabolic syndrome (MS) and cardiovascular disease in adolescent. This study is aimed to identify probable cardio-vascular risk factors in obese adolescents with MS. Methods: Sixty-five obese adolescents with a body mass index (BMI) > 95 percentile were enrolled and divided into two groups with MS or without MS. Left ventricular mass (LVM), left ventricular mass index, ejection fraction, epicardial fat thickness, visceral fat thickness (VFT) and carotid intima-media thickness were measured. Anthropometric and blood chemistry parameters were estimated. Above parameters were compared based on presence or absence of MS. Results: The prevalence of MS was 23.1% in obese adolescents. LVM showed significant correlation with body mass index (BMI), hip circumference (HC), fat mass, total cholesterol (TC), LDL-cholesterol (LDL-C) and waist circumference (WC). VFT significantly correlated with WC, BMI, hip circumflex (HC), obesity index (OI), fat %, fat mass, insulin, TC, LDL-C, insulin, triglyceride (TG), glucose, homeostatic model assessment for insulin resistance (HOMA-IR) and leptin. Conclusions: Screening for the MS in overweight adolescents may help to predict risk of future cardiovascular disease. These data suggest that LVMI and VFT are significant parameters for predicting cardiovascular disease risk in obese adolescents.

Uric acid and progression of chronic kidney disease

The association between serum uric acid levels and human disease has garnered intense interest over the last decade including chronic kidney disease. Animal studies have provided evidence for a potential mechanistic role of uric acid in promoting progression of chronic kidney disease. Epidemiologic studies have also suggested an association between elevated serum uric acid levels and worsening renal function in the general population as well as in patients with chronic kidney disease. However, there is currently insufficient evidence to recommend the use of uric acid-lowering therapy to delay progression of chronic kidney disease in this patient population. Adequately powered, randomized, placebo-controlled trials are required to more precisely evaluate the risk and benefits of uric acid-lowering therapy in pediatric patients.

Lack of Associations between Elevated Serum Uric Acid and Components of Metabolic Syndrome Such as Hypertension, Dyslipidemia, and T2DM in Overweight and Obese Chinese Adults

The overweight and obese population experiences a higher occurrence of both hyperuricemia and metabolic syndrome. The present study was to explore the relationship between serum uric acid and metabolic syndrome-related risk factors among 409 obese Chinese adults (254 women and 155 men) with >24 kg/m² BMI. Based on sex-specific reference ranges, 233 (57%) patients showed elevated serum uric acid. A total of 15 attributes were selected to assess the associations between elevated serum uric acid and components of metabolic syndrome, including serum uric acid, total cholesterol, HDL-C, LDL-C, triglyceride, systolic blood pressure, fasting blood glucose, glycosylated hemoglobin, HOMA-IR, alanine aminotransferase, creatinine, urine microalbumin, muscle mass amount, BMI, and age. Among the participants stratified into three groups of grade I, grade II, and grade III obesity, as well as among the participants stratified into male and female groups, univariate correlation analysis identified a negative association (P < 0.01) for age, positive associations (P < 0.01) for BMI, muscle mass, alanine aminotransferase, and creatinine. The stepwise multivariate logistic regression proved similar associations for age, BMI, creatinine, and alanine aminotransferase. No significant associations were testified between serum uric acid levels and cholesterol, HDL-C, LDL-C, triglyceride, fasting blood glucose, glycosylated hemoglobin, HOMA-IR, and urine microalbumin. Factor analysis illustrated that 15 attributes could be grouped into two common factors and five individual factors. A common underlying factor was identified among uric acid, muscle mass, creatinine, alanine aminotransferase, and BMI. The results indicate that serum uric acid has no apparent association with metabolic syndromes that are commonly characterized by hypertension, dyslipidemia, and T2DM.

Relationship between oxidative stress and inflammation in hyperuricemia: Analysis based on asymptomatic young patients with primary hyperuricemia

The average age of hyperuricemia patients has gradually decreased, but young patients with primary hyperuricemia often do not exhibit clinical symptoms and have not received sufficient attention. However, a lack of symptoms with primary hyperuricemia does not mean that high serum uric acid (UA) levels cannot lead to pathological effects, such as oxidative stress and inflammation, and the specific damage is still unclear. We aimed to determine the relationship between oxidative stress and inflammation to explore the possible role of pathological damage in asymptomatic young patients with primary hyperuricemia.A total of 333 participants were enrolled in our study: 158 asymptomatic young patients with primary hyperuricemia and 175 healthy persons from a health check-up population. Malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and general biochemical markers were measured.We found no differences in biochemical markers (fasting glucose, TG, TC, LDL-C, HDL-C, SCr, BUN, AST, and ALT) between the patients and healthy persons. Subsequent analyses of oxidative stress and inflammation revealed that the serum levels of MDA, IL-6, and TNF-α in the patients were significantly higher than those in the healthy control group (P < .001), and the SOD activity was significantly lower (P < .001). As the UA levels increased, MDA increased significantly and SOD decreased significantly; likewise, IL-6 and TNF-α increased significantly as the UA level increased. MDA showed a significant positive correlation with IL-6 (r = 0.367, P < .001) and TNF-α (r = 0.319, P < .001), and SOD was negatively correlated with IL-6 (r = -0.241, P < .01) and TNF-α (r = -0.308, P < .001). Multivariable logistic regression analysis showed that UA (OR: 2.379, 95% CI: 1.698-3.286, P < .001; OR: 3.261, 95% CI: 1.729-3.857, P < .001; for IL-6 and TNF-α, respectively) and MDA (OR: 1.836, 95% CI: 1.283-2.517, P < .01; OR: 2.532, 95% CI: 1.693-3.102, P < .001; for IL-6 and TNF-α, respectively) were risk factors for high IL-6 and TNF-α and that SOD (OR: 0.517, 95% CI: 0.428-0.763, P < .01; OR: 0.603, 95% CI: 0.415-0.699, P < .001; for IL-6 and TNF-α, respectively) was a protective factor.In our study, some abnormal pathological effects were found in asymptomatic young patients with hyperuricemia, suggesting that in young hyperuricemia patients, oxidative stress, inflammation and the inflammatory response may be related to the oxidative stress induced by UA. Therefore, we should pay more attention to the pathological damage caused by these alterations.

Serum Uric Acid Is Independently Associated with Coronary Calcification in an Asymptomatic Population

Detecting early-stage atherosclerosis is an important step towards cardiovascular disease prevention. Coronary artery calcium (CAC) score is a sensitive and non-invasive tool for detecting coronary atherosclerosis. Higher serum uric acid (SUA) levels are known to be associated with cardiovascular diseases. However, there is inconsistency regarding the independence of the association. The aim of our study was to assess the association of CAC and SUA in an asymptomatic population. CAC scans of 281 participants were analyzed in a voluntary screening program. A health questionnaire, physical examination, and laboratory tests were also performed. Participants with a history of cardiovascular disease were excluded from the analysis. 36.3% (n = 102) of the participants had no detectable CAC and 13.9% (n = 39) had a CAC score of > 300. SUA showed positive correlation with CAC score (0.175, p < 0.01). SUA was independently associated with Ca score > 300 (OR 5.17, p = 0.01) after the effects of conventional risk factors were eliminated.

Differential analysis of disease risk assessment using binary logistic regression with different analysis strategies

Objective

To investigate the importance of controlling confounding factors during binary logistic regression analysis.

Methods

Male coronary heart disease (CHD) patients (n = 664) and healthy control subjects (n = 400) were enrolled. Fourteen indexes were collected: age, uric acid, cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, apolipoprotein A1, apolipoprotein B100, lipoprotein a, homocysteine, total bilirubin, direct bilirubin, indirect bilirubin, and γ-glutamyl transferase. Associations between these indexes and CHD were assessed by logistic regression, and results were compared by using different analysis strategies.

Results

1) Without controlling for confounding factors, 14 indexes were directly inputted in the analysis process, and 11 indexes were finally retained. A model was obtained with conflicting results. 2) According to the application conditions for logistic regression analysis, all 14 indexes were weighed according to their variances and the results of correlation analysis. Seven indexes were finally included in the model. The model was verified by receiver operating characteristic curve, with an area under the curve of 0.927.

Conclusions

When binary logistic regression analysis is used to evaluate the complex relationships between risk factors and CHD, strict control of confounding factors can improve the reliability and validity of the analysis.

Insulin resistance, serum uric acid and metabolic syndrome are linked to cardiovascular dysfunction in pediatric obesity

INTRODUCTION

Childhood obesity is associated with cardiovascular abnormalities but little is known on the potential correlation between early cardiovascular and metabolic alterations.

AIM

Aims of this study were 1) to evaluate early cardiovascular abnormalities in a large population of obese children and adolescents compared with a normal weight counterpart, 2) to investigate their potential association with insulin resistance (IR), serum uric acid (sUA) and metabolic syndrome (MetS).

METHODS

This was a single-center case-control study. Eighty obese (OB) subjects (6-16years) and 20 normal weight (NW) matched controls were consecutively recruited. In the whole population we performed an anthropometric and a cardiovascular assessment. OB patients also underwent an OGTT and biochemical evaluations.

RESULTS

OB children showed greater left atrial (LA) and ventricular (LV) dimensions and mass and higher carotid artery intima-media thickness (CIMT), compared with NW controls. The BMI z-score, waist circumference, IR and sUA were positively related with LA and LV dimensions and mass. OB subjects with MetS (46.3%) showed greater LA diameter (p=0.001) and LV area (p=0.01) and volume (p=0.04) compared with OB children without MetS. LA diameter and LV dimensions and mass were significantly dependent on the number of criteria for MetS. Mets, sUA and IR were significant predictors of left heart dimensions and mass in obese children.

CONCLUSIONS

Obesity and MetS are associated with abnormal cardiovascular response during childhood. Hyperuricemia can be an early marker of cardiovascular dysfunction and the routine determination of circulating levels of sUA should be implemented during risk stratification among pediatric age.

Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents

These pediatric hypertension guidelines are an update to the 2004 "Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents." Significant changes in these guidelines include (1) the replacement of the term "prehypertension" with the term "elevated blood pressure," (2) new normative pediatric blood pressure (BP) tables based on normal-weight children, (3) a simplified screening table for identifying BPs needing further evaluation, (4) a simplified BP classification in adolescents ≥13 years of age that aligns with the forthcoming American Heart Association and American College of Cardiology adult BP guidelines, (5) a more limited recommendation to perform screening BP measurements only at preventive care visits, (6) streamlined recommendations on the initial evaluation and management of abnormal BPs, (7) an expanded role for ambulatory BP monitoring in the diagnosis and management of pediatric hypertension, and (8) revised recommendations on when to perform echocardiography in the evaluation of newly diagnosed hypertensive pediatric patients (generally only before medication initiation), along with a revised definition of left ventricular hypertrophy. These guidelines include 30 Key Action Statements and 27 additional recommendations derived from a comprehensive review of almost 15 000 published articles between January 2004 and July 2016. Each Key Action Statement includes level of evidence, benefit-harm relationship, and strength of recommendation. This clinical practice guideline, endorsed by the American Heart Association, is intended to foster a patient- and family-centered approach to care, reduce unnecessary and costly medical interventions, improve patient diagnoses and outcomes, support implementation, and provide direction for future research.

Uric acid in the pathogenesis of metabolic, renal, and cardiovascular diseases: A review

The association between uric acid (UA) on one side and systemic hypertension (Htn), dyslipidemia, glucose intolerance, overweight, fatty liver, renal disease and cardiovascular disease (CVD) on the other side is well recognized. However, the causal relationship between UA and these different clinical problems is still debatable. The recent years have witnessed hundreds of experimental and clinical trials that favored the opinion that UA is a probable player in the pathogenesis of these disease entities. These studies disclosed the strong association between hyperuricemia and metabolic syndrome (MS), obesity, Htn, type 2 diabetes mellitus (DM), non-alcoholic fatty liver disease, hypertriglyceridemia, acute kidney injury, chronic kidney disease (CKD), coronary heart disease (CHD), heart failure and increased mortality among cardiac and CKD patients. The association between UA and nephrolithiasis or preeclampsia is a non-debatable association. Recent experimental trials have disclosed different changes in enzyme activities induced by UA. Nitric oxide (NO) synthase, adenosine monophosphate kinase (AMPK), adenosine monophosphate dehydrogenase (AMPD), and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase are affected by UA. These changes in enzymatic activities can lead to the observed biochemical and pathological changes associated with UA. The recent experimental, clinical, interventional, and epidemiologic trials favor the concept of a causative role of UA in the pathogenesis of MS, renal, and CVDs.

Effect of Nutrition Counseling Program on Weight Control in Obese University Students

This study was conducted to investigate the effect of nutrition counseling program and related factors on weight control for obese university students. Subjects were 24 students with a body mass index (BMI) of 25 or above. The program was conducted from September 16th to November 18th, 2015. Change of body composition, blood index and nutrient intake were observed in subjects before and after the program. The average age of the subjects was 23.2 years old and the percentage of male and female was 66.7% and 33.0%, respectively. There were tendencies of decrease in weight, amount of body fat, BMI, and body fat percentage. The blood test showed that values of all biochemical parameters were in the normal range before and after the program. When the change of the nutrient intake was examined and compared with the Dietary Reference Intakes for Koreans (KDRIs), there was a tendency of decreased intake in most of the nutrients including protein. However, the nutrient quality index showed increasing tendency, which implies that the intake of micronutrients was getting balances simultaneously with the decrease of calorie intake.