Association between serum uric acid and metabolic syndrome components in prepubertal obese children (Tanner Stage I) from Nuevo León, Mexico - a preliminary study

Impact of body mass index on the association between kidney function and insulin resistance in diabetic and nondiabetic populations

AIMS/INTRODUCTION

The kidneys play a role in regulating insulin metabolism, and kidney function may indicate the progression to insulin resistance (IR) in individuals with obesity and diabetes. We evaluated the relationship between kidney function biomarkers and IR in diabetic and nondiabetic adults categorized by body mass index (BMI).

METHODS

A total of 8,272 adults from the China Health and Nutrition Survey 2009 were categorized into four groups based on BMI (overweight/obesity vs underweight/normal weight) and diabetes status (diabetes vs non-diabetes). Univariable and multivariable linear regression, along with restricted cubic spline regression, were used to determine the relationship between estimated glomerular filtration rate (eGFR), creatinine, urea nitrogen, uric acid (UA), and homeostasis model assessment for insulin resistance (HOMA-IR).

RESULTS

The relationship between kidney function biomarkers and IR only existed in the overweight/obese populations and varied by diabetic status. In diabetic patients, linear associations were observed: eGFR was negatively associated with HOMA-IR, and creatinine was positively associated. In nondiabetic individuals, nonlinear associations were found. The relationship between eGFR and HOMA-IR followed an L-shaped curve: HOMA-IR decreased as eGFR increased up to 100 mL/min/1.73 m2, then slightly increased. The UA-HOMA-IR association showed an inverted L-shape: HOMA-IR increased with higher UA levels, plateauing after UA exceeded 360 μmol/L.

CONCLUSIONS

Kidney function biomarkers are associated with IR in overweight/obese populations, with and without diabetes. eGFR and creatinine can be indicators of IR in overweight/obese subjects with diabetes, while eGFR and UA may be used in those without diabetes.

Salivary uric acid across child development and associations with weight, height, and body mass index

Introduction

Obesity during childhood is a serious and growing chronic disease with consequences for lifelong health. In an effort to advance research into the preclinical indicators of pediatric obesity, we examined longitudinal assessments of uric acid concentrations in saliva among a cohort of healthy children from age 6-months to 12-years (n's per assessment range from 294 to 727).

Methods

Using data from a subsample of participants from the Family Life Project (an Environmental influences on Child Health Outcomes Program cohort), we: (1) characterized salivary uric acid (sUA) concentrations from infancy to early adolescence by sex and race; (2) assessed changes in sUA levels across development; and (3) evaluated associations between sUA concentrations and measures of child weight, height, and body mass index (BMI). Across four assessments conducted at 6-, 24-, 90-, and 154-months of age, 2,000 saliva samples were assayed for UA from 781 participants (217 participants had sUA data at all assessments).

Results

There were no significant differences in sUA concentrations by sex at any assessment, and differences in sUA concentrations between White and non-White children varied by age. At the 90- and 154-month assessments, sUA concentrations were positively correlated with measures of child weight, height, and BMI (90-month: weight- ρ(610) = 0.13, p < 0.01; height- ρ(607) = 0.10, p < 0.05; BMI- ρ(604) = 0.13, p < 0.01; 154-month: weight- ρ(723) = 0.18, p < 0.0001; height- ρ(721) = 0.10, p < 0.01; BMI- ρ(721) = 0.17, p < 0.0001). Group based trajectory modeling identified two groups of children in our sample with distinct patterns of sUA developmental change. The majority (72%) of participants showed no significant changes in sUA across time ("Stable" group), while 28% showed increases in sUA across childhood with steep increases from the 90- to 154-month assessments ("Increasing" group). Children in the Increasing group exhibited higher sUA concentrations at all assessments (6-month: t(215) = -5.71, p < 0.001; 24-month: t(215) = -2.89, p < 0.01; 90-month: t(215) = -3.89, p < 0.001; 154-month: t(215) = -19.28, p < 0.001) and higher weight at the 24- and 90-month assessments (24-month: t(214) = -2.37, p < 0.05; 90-month: t(214) = -2.73, p < 0.01).

Discussion

Our findings support the potential utility of sUA as a novel, minimally-invasive biomarker that may help advance understanding of the mechanisms underlying obesity as well as further surveillance and monitoring efforts for pediatric obesity on a large-scale.

Glycemia and associated factors in a pediatric population in Mexico

Aims

In this study, we evaluated the association of sociodemographic, lifestyle and cardiometabolic factors with blood glucose levels in children and adolescents in Mexico.

Methods

An analytical cross-sectional study of 642 children and adolescents aged 6 to 19 years from different educational centers located in municipalities of the state of San Luis Potosí, Mexico, was carried out. Pearson χ2 and Spearman correlation tests and multiple linear regression models were used to evaluate the associations of the variables with glycemia.

Results

The prevalence of prediabetes was 8.0% in both sexes. Male participants were more likely to develop hyperglycemia than female participants (OR 2.7, 95% CI: 1.5-5.0). The variables associated with glucose levels were male sex, high socioeconomic status, inadequate diet, high blood pressure, and increased total cholesterol, LDL cholesterol, and triglycerides, which also explained up to 15.6% (p < 0.05) of the variability in glucose concentrations.

Conclusion

The detection of sociodemographic, lifestyle and cardiometabolic factors in children and adolescents will contribute to the implementation of prevention strategies for cardiometabolic diseases, among which prediabetes is common.

Decreased level of soluble receptor activator of nuclear factor-κβ ligand (sRANKL) in overweight and obese children

INTRODUCTION

Childhood obesity contributes to the development of cardiovascular diseases. The molecular pathway - receptor activator of nuclear factor-κβ ligand (RANKL), its receptor RANK and osteoprotegerin (OPG) - takes part not only in bone metabolism but is also involved in the atherosclerosis process. RANKL stimulates osteogenic differentiation and calcification of vascular smooth cells. The associations between the OPG-sRANKL system and various cardiovascular risk factors were displayed. We aimed to evaluate the relationships between serum sRANKL (soluble RANKL) levels and the OPG/sRANKL ratio with cardiometabolic risk factors in overweight and obese children.

MATERIAL AND METHODS

The study included 70 children with overweight and obesity (mean age 13.0 ± 2.8) and 35 age-matched normal weight, healthy peers as a control group. In all patients, anthropometric measurements and laboratory tests were performed. Additionally, an oral glucose tolerance test (OGTT) was made only in overweight and obese children. Atherogenic and insulin resistance indices were calculated.

RESULTS

Overweight and obese children had lower sRANKL levels compared to the control group (median 276.95 vs 325.90, p=0.011), and consequently a higher OPG/sRANKL ratio (0.02 vs 0.01, p = 0.013). The studied children in the lowest quartile of sRANKL levels had higher body weight, Body Mass Index, waist circumference and increased glucose and insulin levels 60 minutes after OGTT and higher uric acid values compared to children in the highest quartile. In multivariable linear regression analysis sRANKL negatively correlated only with uric acid (β = - 0.508, p = 0.041). No association was found for the OPG/sRANKL ratio.

CONCLUSION

Excess fat mass seems to alter the OPG/RANKL ratio mainly by reducing serum sRANKL levels. The correlation between sRANKL and uric acid may suggest a contribution of the OPG-sRANKL system in the cardiometabolic process, but that observation should be confirmed in future studies.

Antihyperuricemic Effect of Dendropanax morbifera Leaf Extract in Rodent Models

Dendropanax morbifera is a well-known traditional medicine used in China and Korea to treat intestinal disorders, urosis, diuresis, and chronic glomerulonephritis. Hyperuricemia is a metabolic disorder characterized by a high uric acid level in serum due to an imbalance between uric acid production and excretion and causes gout. Recently, the prevalence of hyperuricemia worldwide has been continuously increasing. Xanthine oxidase (XOD) inhibitors (allopurinol (ALP) and febuxostat) and uricosuric agents (benzbromarone and probenecid) are used to treat hyperuricemia clinically. However, because these drugs are poorly tolerated and cause side effects, such as kidney diseases, hepatotoxicity, gastrointestinal symptoms, and hypersensitivity syndrome, only a limited number of drugs are available. We investigated the antihyperuricemic effects of Dendropanax morbifera leaf ethanol extract (DMLE) and its underlying mechanisms of action through in vitro and in vivo studies. We evaluated uric acid levels in serum and urine, and xanthine oxidase (XOD) inhibition activity in the serum and liver tissue of a hyperuricemic rat model of potassium oxonate (PO)-induced hyperuricemic rats. In vitro study, XOD-inhibitory activity was the lowest among the test substances at the IC50 of ALP. However, the IC50 of DMLE-70 was significantly low compared with that of other DMLEs (p < 0.05). In PO-induced hyperuricemic rats, uric acid (UA) levels in serum and urine were significantly reduced in all DMLE-70 and allopurinol-treated (ALT) groups than in the PC group (p < 0.05). UA levels in urine were lower than those in serum in all DME groups. In PO-induced hyperuricemic rats, DMEE-200 reduced UA concentration in serum and increased UA excretion in the urine. These findings suggest that DMLE exerts antihyperuricemic and uricosuric effects on promoting UA excretion by enhanced secretion and inhibition of UA reabsorption in the kidneys. Thus, DMLE may be a potential treatment for hyperuricemia and gout.

Association of serum uric acid concentration with components of pediatric metabolic syndrome: A systematic review and meta-analysis

Background:

Hyperuricemia is implicated in the pathogenesis of inflammatory diseases and metabolic disorders. Metabolic syndrome (MetS) in childhood is one of the most important causes of different noncommunicable diseases in adulthood. This study aimed to systematically review the association between serum uric acid (UA) concentration and components of pediatric MetS.

Materials and Methods:

In this meta-analysis and systematic review, related articles were gathered by searching English databases including PubMed, Web of Science, Scopus, and Google Scholar. We used the following keywords: uric acid, metabolic syndrome, hypertension, fasting blood sugar (FBS), hyperglycemia; the search was limited to English language and included observational and cohort studies performed among children or adolescents. Pooled relative risks (odds ratio [OR]) and corresponding 95% confidence interval (95% CI) were extracted. A random-effect model was used.

Results:

On the basis of 34 eligible studies, the pooled correlation between UA with metabolic components including FBS (r = 0.24, 95% CI = 0.09–0.40), fasting insulin (r = 0.26, 95% CI = 0.15–0.37), and hyperglycemia (r for triglyceride and UA = 0.23, 95% CI = 0.19–0.38) (r for high-density lipoprotein and UA = −0.28, 95% CI = −0.37 to −0.20) was statistically significant. The association of both diastolic blood pressure (DBP) and systolic blood pressure (SBP) was statistically significant with UA (r for SBP and UA = 0.34, 95% CI = 0.24–0.43; r for DBP and UA = 0.18, 95% CI = 0.11–0.25). The OR between risk of abdominal obesity with UA was statistically significant (OR = 2.62, 95% CI = 1.41–3.84).

Conclusion:

Serum UA concentration is associated with major components of the pediatric MetS. Its measurement and control should be underscored in at-risk children and adolescents.

The roles of triglyceride/high-density lipoprotein cholesterol ratio and uric acid as predisposing factors for metabolic syndrome in healthy children

PURPOSE

To estimate the roles of triglyceride/high-density lipoprotein cholesterol (TG/HDL) ratio and uric acid in predisposition for metabolic syndrome (MetS) and its components in healthy children.

METHODS

Anthropometric and biochemical analyses were performed on 110 children, aged 5 to 12 years, from the Greek county of Laconia. The children were studied as a whole population and in separate groups according to age and predisposition to MetS after taking into consideration International Diabetes Federation criteria, body mass index, and lipid profile.

RESULTS

Seventeen percent of children exhibited predisposition to MetS, while 39.1% had TG/HDL ratio &gt;1, and 3.64% had high level of uric acid. According to a receiver operating characteristic curve analysis, the relative probability for MetS predisposition sextupled when TG/HDL ratio was ≥1 (odds ratio [OR], 5.986; 95% confidence interval [CI], 1.968-18.205). Children in the total population and those aged &lt; 9 years had a greater probability for increased low-density lipoprotein (LDL) cholesterol (OR, 3.614; 95% CI, 1.561-8.365) when TG/HDL ratio was ≥ 1. The TG/HDL ratio was positively correlated with body mass index (BMI) (P=0.035) in children without MetS, cholesterol in the total population (P=0.06) and children ≥9 years old (P=0.026), and with LDL in the total population and both age groups (P=0.001). The TG/HDL ratio was also positively correlated with alanine aminotransferase in the total population (P=0.033) and gamma-glutamyl transferase in most studied groups (P&lt;0.001). Uric acid was positively correlated with waist circumference in the total population (P=0.043) and in those without MetS (P=0.027). It was also positively correlated with BMI, TG, cholesterol, and TG/HDL ratio and negatively correlated with HDL in most studied groups (P&lt;0.005).

CONCLUSION

The studied parameters correlated with MetS components and could be characterized as effective indexes for childhood MetS, regardless of age and predisposition to MetS.

Influence of Genetic and Non-Genetic Risk Factors for Serum Uric Acid Levels and Hyperuricemia in Mexicans

Risk of hyperuricemia is modified by genetic and environmental factors. Our aim was to identify factors associated with serum uric acid levels and hyperuricemia in Mexicans. A pilot Genome-wide association study GWAS was performed in a subgroup of participants (n = 411) from the Health Workers Cohort Study (HWCS). Single nucleotide polymorphisms (SNPs) associated with serum uric acid levels were validated in all the HWCS participants (n = 1939) and replicated in independent children (n = 1080) and adult (n = 1073) case-control studies. The meta-analysis of the whole HWCS and replication samples identified three SLC2A9 SNPs: rs1014290 (p = 2.3 × 10⁻⁶⁴), rs3775948 (p = 8.2 × 10⁻⁶⁴) and rs11722228 (p = 1.1 × 10⁻¹⁷); and an ABCG2 missense SNP, rs2231142 (p = 1.0 × 10⁻¹⁸). Among the non-genetic factors identified, the visceral adiposity index, smoking, the metabolic syndrome and its components (waist circumference, blood pressure, glucose and hyperlipidemia) were associated with increased serum uric acid levels and hyperuricemia (p < 0.05). Among the female HWCS participants, the odds ratio for hyperuricemia was 1.24 (95% CI, 1.01–1.53) per unit increase in soft drink consumption. As reported in other studies, our findings indicate that diet, adiposity and genetic variation contribute to the elevated prevalence of hyperuricemia in Mexico.