Associations Between Low Serum Urate, Body Composition, and Mortality

U-shaped association of uric acid to HDL cholesterol ratio (UHR) with ALL-cause and cardiovascular mortality in diabetic patients: NHANES 1999-2018

OBJECTIVE

To investigate the relationship between the uric acid to high-density lipoprotein cholesterol ratio (UHR) and ALL-cause and cardiovascular mortality among diabetic patients.

METHODS

This study utilized health data from diabetic patients included in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. The Kaplan-Meier curves was employed to preliminarily explore the association between UHR, its components, and all-cause and cardiovascular mortality in diabetic patients, as well as to analyze UHR levels and mortality across different genders. Subsequently, the Cox proportional hazards model was used to further investigate the relationship between UHR, its components, and mortality in diabetic patients. Restricted cubic spline (RCS) curves were applied to examine the nonlinear relationship between UHR, its components, and mortality, with a particular focus on the association between UHR and mortality across different genders.

RESULTS

This longitudinal cohort study included a total of 6,370 participants, comprising 3,268 males and 3,102 females. Kaplan-Meier analysis revealed a positive correlation between UHR, UA, and mortality in diabetic patients, while the association between HDL and mortality was negligible. The Cox proportional hazards model demonstrated a positive association between UHR and mortality in the diabetic population, while the statistical effects of UA and HDL on mortality were less pronounced compared to UHR. When analyzed by gender, no significant linear relationship was observed between UHR and mortality in either males or females. Subsequently, RCS analysis indicated a U-shaped nonlinear relationship between UHR and mortality in the overall diabetic population and among female patients, with a similar trend observed in males. Furthermore, stratified RCS analysis confirmed the persistence of the U-shaped relationship between UHR and prognosis across most subgroups.

CONCLUSION

This study found a U-shaped relationship between UHR and both ALL-cause and cardiovascular mortality in diabetic population. This suggests that clinicians should control UHR around 9-10 to improve the long-term prognosis of diabetic patients.

Impact of Early Life Famine Exposure on Body Composition and Metabolic Profiles in Adulthood

The relationship between the famine and metabolic syndrome has been reported, but there is a lack of more detailed changes in metabolic profiles. It is unclear how famine affects body composition. This study included 21,142 participants from the China National Health Survey. The body mass index (BMI), fat mass index (FMI), and fat-free mass index (FFMI) were calculated. Systolic blood pressure (SBP), diastolic blood pressure (DBP), blood lipids, and fasting blood glucose (FBG) were measured. Multivariate adjusted linear regression models were used to assess the association between famine and outcome. Our results shown that fetal-exposed group had higher BMI and FMI (β > 0). Childhood-exposed group showed an average decrease of 0.08 standard deviation (SD) in FFMI, and adolescence-exposed group had lower BMI and FFMI than non-exposed group. SBP were 0.38 SD higher in fetal-exposed group, 0.58 SD higher in childhood-exposed group and 0.85 SD higher in adolescence-exposed group than non-exposed group. Famine-exposed groups had higher total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and FBG levels (β > 0). For females with famine exposure, they had a higher BMI, FMI, LDL-C, TG, and TC than males. Overall, early famine exposure is associated with increased blood pressure, LDL-C, TC, and FBG. Muscle mass loss in adulthood associated with childhood and adolescence famine exposure. Famine-exposed females appear to have higher levels of body fat and blood lipids.

Inverse association between uric acid levels and muscle quality index in adults: a cross-sectional analysis of NHANES 2011-2014

OBJECTIVE

The objective of this study was to delineate the association between serum uric acid (UA) levels and Muscle Quality Index (MQI), assessing muscle strength relative to mass, in adults aged 20 to 59 years.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, this study examined the association between UA levels and MQI-a ratio of muscle strength to mass. Weighted linear models, adjusted for potential confounders, assessed the relationship, with a generalized additive model (GAM) probing for non-linear patterns. Subgroup analyses and interaction effects were conducted using weighted linear regression across diverse demographic and clinical groups to ensure the robustness and reliability of our findings.

RESULTS

Among 5,277 participants, a significant inverse association was observed between UA levels and MQI, with a 0.08 decrease in MQI per 1 mg/dL increase in UA (95% CI: -0.11 to -0.06, p < 0.001). The negative trend was dose-dependent across UA quartiles, which was most pronounced in the highest quartile (Q4: -0.28, 95% CI: -0.36 to -0.19, p < 0.001). Curve-fitting analysis revealed a consistent inverse relationship without evidence of non-linearity. Stratified analyses reinforced the core findings across all examined subgroups, highlighting the universal relevance of the observed association.

CONCLUSION

Our findings demonstrate a significant inverse association between elevated serum UA levels and MQI, highlighting the potential importance of uric acid management in enhancing muscle quality among young and middle-aged adults. The consistency of this relationship across different subgroups underscores the need for targeted strategies and interventions to manage UA levels. Future research should explore longitudinal impacts and intervention outcomes to further elucidate the potential benefits of uric acid management on muscle health.

Association of serum uric acid levels with risk of epilepsy: A national population-based study

BACKGROUND

Uric acid (UA) serves as a crucial endogenous antioxidant in the body, offering protection against oxidative stress, whichmaycontributetoepilepsypathogenesis. The association between serum UA levels and epilepsy remains uncertain. This study aimed to examine the potential connections between serum UA levels and epilepsy in US adults.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2013-2018, a cross-sectional analysis was conducted. Weighted logistic regression analyses were employed to assess the potential link between serum UA levels and the risk of epilepsy. Additionally, sensitivity analyses were conducted to evaluate the reliability of the results.

RESULTS

We included 15,373 participants, of whom 136 (0.79 %) had epilepsy. Following adjustment for multiple variables, participants with serum UA levels <4.1 mg/dl had an odds ratio of 2.24 (95 % CI: 1.12-4.47, P = 0.023) for epilepsy compared to those with serum UA levels of 5.8-6.5 mg/dl. The results of the sensitivity analyses corroborated the initial findings.

CONCLUSIONS

Our study revealed a significant association between lower serum UA levels and heightened risks of epilepsy, suggesting that low UA levels may serve as an independent risk factor for epilepsy. A marginal increase in UA levels within the normal range may act as a protective factor against epilepsy.

Skeletal muscle mass and quality in gout patients versus non-gout controls: A computed tomography imaging study

OBJECTIVE

Patients with gout are at elevated risk of multiple vascular and metabolic comorbidities. Whether they are also at risk of sarcopenia, which is known to affect patients with other rheumatic diseases, has not been previously assessed. We examined whether patients with gout have decreased lumbar muscle quality and quantity, indicating an association between gout and sarcopenia.

METHODS

Fifty gout subjects and 25 controls, ages 45-80, underwent computed tomography imaging of the lumbosacral spine. We measured muscle quantity (skeletal muscle area [SMA] and index [SMI]) and quality (skeletal muscle radiation attenuation [SMRA] and intermuscular adipose tissue [IMAT] area and index [IMATI]) of the psoas and erector spinae muscles at the L3 level.

RESULTS

Seventy subjects (45 gout and 25 controls) were included in the analysis. Gout subjects had higher BMI, more kidney disease and hypertension, lower exercise frequency, and higher mean serum urate and creatinine vs. controls. Lumbar SMRA was significantly lower in gout subjects vs. controls, indicating reduced muscle quality. Lumbar IMAT area was significantly higher in gout subjects vs. controls, as was lumbar IMATI, indicating increased muscle adiposity. These differences persisted after adjusting for potential confounders. In contrast, there was no significant difference between gout and control groups in lumbar SMA or lumbar SMI, suggesting that muscle quantity may not be routinely affected by the diagnosis of gout.

CONCLUSIONS

Gout patients exhibit decreased lumbar muscle quality compared with controls, consistent with an association between gout and sarcopenia.

Geriatric nutrition risk index in the prediction of all-cause and cardiovascular mortality in older adults with hyperlipidemia: NHANES 1999-2018

BACKGROUND

Malnutrition is linked to a higher risk of unfavorable outcomes in various illnesses. The present investigation explored the correlation between inadequate nutritional condition and outcomes in older individuals diagnosed with hyperlipidemia.

METHODS

The geriatric nutritional risk index (GNRI) was used to evaluate the nutritional status. All patients were divided into two groups according to GNRI. A Kaplan-Meier analysis was used to assess the survival rates of different groups at risk of malnutrition. In addition, GNRI was used in COX proportional risk regression models to evaluate its predictive effect on both overall mortality and cardiovascular mortality among patients with hyperlipidemia. Furthermore, the study employed restricted cubic splines (RCS) to examine the nonlinear correlation between GNRI and mortality.

RESULTS

The study included 4,532 elderly individuals diagnosed with hyperlipidemia. During a median follow-up duration of 139 months, a total of 1498 deaths from all causes and 410 deaths from cardiovascular causes occurred. The Kaplan-Meier analysis demonstrated significantly poorer survival among individuals at risk of malnutrition, as indicated by the GNRI. In the malnutrition risk group, the modified COX proportional hazards model revealed that a decrease in GNRI was associated with a higher risk of all-cause mortality (HR=1.686, 95% CI 1.212-2.347) and cardiovascular mortality (HR=3.041, 95% CI 1.797-5.147). Furthermore, the restricted cubic splines revealed a non-linear association between GNRI and both all-cause mortality and cardiovascular mortality (p-value for non-linearity = 0.0039, p-value for non-linearity=0.0386).

CONCLUSIONS

In older patients with hyperlipidemia, lower levels of GNRI are associated with mortality. The GNRI could potentially be used to predict all-cause mortality and cardiovascular mortality.

Relationship between serum uric acid and sarcopenia in geriatric heart failure patients with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) presents a serious risk to human health. The increased prevalence of sarcopenia in the HFpEF population has a negative impact on patient prognosis. Uric acid (UA) is the byproduct of purine metabolism and is harmful to the cardiovascular system. This study aims to establish the potential relationship between sarcopenia and serum UA in HFpEF patients.

METHODS

Data were obtained from 180 individuals (aged ≥60 years) with HFpEF admitted to the Geriatric Department of Jiangsu Province Hospital between January 2021 and December 2022. The UA values were grouped into 4 quartiles (Q1-Q4). Logistic generalized linear models and restricted cubic spline (RCS) regression were used to analyze the relationship between sarcopenia and UA. Subgroups based on gender were utilised for further analysis.

RESULTS

After adjusting for covariates, odds ratios (ORs) and 95 % confidence intervals (CIs) for sarcopenia prevalence in the 2nd, 3rd, and 4th quartiles were 2.56 (0.57-12.65), 4.94 (1.10-24.49), and 6.95 (1.30-44.25), respectively, unlike the 1st quartile (P for trend = 0.022). The RCS plot demonstrated a positive linear relationship between serum UA levels and sarcopenia (P for non-linearity = 0.190). A sex-based subgroup analysis revealed a statistically significant relationship between UA and sarcopenia in males (P < 0.05).

CONCLUSIONS

In summary, the prevalence of sarcopenia is positively related to serum UA levels among the elderly diagnosed with HFpEF. Due to the cross-sectional nature of the study design, additional investigations are necessary to validate our findings and identify the optimal range for UA reduction.

Phthalate and gallstones: the mediation of insulin

Background

Exposure to a mixture of environmental chemicals may cause gallstone, but the evidence remains equivocal. The current study aims to investigate the association between phthalate metabolites and gallstones, and to explore their mediators.

Methods

Data from the National Health and Nutrition Examination Survey 2017-2018 on U.S. adults (≥20 years) were analyzed to explore the association between phthalate metabolites and gallstones by employed survey-weighted logistic regression, restricted cubic spline (RCS), weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR). Mediation analyses examined the role of oxidative stress markers, inflammatory markers, metabolic syndrome, body composition, diabetes, and insulin.

Results

The current study included 1,384 participants, representing 200.6 million U.S. adults. Our results indicated a significant association between phthalate metabolites, particularly high molecular weight metabolites such as Di(2-ethylhexyl) phthalate (DEHP) and 1,2-Cyclohexane dicarboxylic acid diisononyl ester (DINCH), and gallstones. Furthermore, mediation analyses indicated that phthalate metabolites may play a role in the development of gallstones by influencing insulin secretion. Subgroup analyses did not reveal significant interaction.

Conclusion

The association between exposure to phthalates and the occurrence of gallstones, potentially mediated by hyperinsulinemia from a nationally representative epidemiological perspective. These insights contribute to a better understanding of the potential health implications of plasticizers, emphasizing the need for proactive management measures.

Uric acid formation is driven by crosstalk between skeletal muscle and other cell types

Hyperuricemia is implicated in numerous pathologies, but the mechanisms underlying uric acid production are poorly understood. Using a combination of mouse studies, cell culture studies, and human serum samples, we sought to determine the cellular source of uric acid. In mice, fasting and glucocorticoid treatment increased serum uric acid and uric acid release from ex vivo-incubated skeletal muscle. In vitro, glucocorticoids and the transcription factor FoxO3 increased purine nucleotide degradation and purine release from differentiated muscle cells, which coincided with the transcriptional upregulation of AMP deaminase 3, a rate-limiting enzyme in adenine nucleotide degradation. Heavy isotope tracing during coculture experiments revealed that oxidation of muscle purines to uric acid required their transfer from muscle cells to a cell type that expresses xanthine oxidoreductase, such as endothelial cells. Last, in healthy women, matched for age and body composition, serum uric acid was greater in individuals scoring below average on standard physical function assessments. Together, these studies reveal skeletal muscle purine degradation is an underlying driver of uric acid production, with the final step of uric acid production occurring primarily in a nonmuscle cell type. This suggests that skeletal muscle fiber purine degradation may represent a therapeutic target to reduce serum uric acid and treat numerous pathologies.

The relationship between caffeine and its metabolites and bone mineral density in postmenopausal women: a cross-sectional analysis from the NHANES database

We aim to explore the association between caffeine and its metabolites and bone mineral density (BMD) in postmenopausal women. Data of 4286 postmenopausal women were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2009-14 in this cross-sectional study. Weighted linear regression and stepwise regression analyses were used to screen the covariates. Weighted univariate and multivariate linear regression analyses were used to explore the associations between caffeine and its metabolites and BMD. The evaluation index was estimated value (β) with 95 % confidence intervals (CIs). We also explored these relationships in age subgroups. The median BMD level among the eligible women was 0⋅7 gm/cm2. After adjusting for covariates including age, body mass index (BMI), fat intake, Calcium (Ca) supplements, diabetes mellitus (DM), angina pectoris, parental history of osteoporosis (OP), anti-osteoporosis therapy, poverty income ratio (PIR), vitamin D (VD) supplements, coronary heart disease (CHD), and previous fracture, we found that caffeine intake was not significantly related to the BMD reduction (β = 0, P = 0⋅135). However, caffeine metabolites, including MethyluricAcid3, MethyluricAcid7, MethyluricAcid37, Methylxanthine3, and Methylxanthine37, were negatively associated with the BMD (all P < 0⋅05). In addition, MethyluricAcid37 and Methylxanthine37 were negatively associated with BMD in females aged <65 years old, while MethyluricAcid3 and Methylxanthine3 were noteworthy in those who aged ≥65 years old. The roles of caffeine and its metabolites in BMD reduction and OP in postmenopausal women needed further exploration.

Association of serum uric acid with all-cause and cardiovascular mortality in obstructive sleep apnea

The study investigated the association between Serum Uric Acid (SUA) levels and all-cause as well as cardiovascular mortality in patients with Obstructive Sleep Apnea (OSA). This prospective cohort study enrolled participants with OSA from four cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2008, and 2015-2018. A weighted Cox proportional hazards model was used to assess adjusted hazard ratios (aHRs) and their corresponding 95% confidence intervals (CI) for all-cause and cardiovascular mortality. Additionally, multivariable logistic regression and restricted cubic splines (RCS) models were employed to examine nonlinear relationships between SUA and all-cause and cardiovascular mortality. Among the 5,584 OSA participants included in the study, covering the four NHANES cycles and with a median follow-up of 4.333 years, a total of 537 deaths were observed, including 108 deaths attributed to cardiovascular disease. Comparing the fourth quartile (Q4) of uric acid levels, both the fifth quartile (Q5) (aHRs = 1.51, 95% CI [1.08, 2.12]) and the second quartile (Q2) (aHRs = 1.53, 95% CI [1.04, 2.25]) of uric acid levels were independently associated with an increased risk of all-cause mortality. Furthermore, comparing the fourth quartile (Q4) of uric acid levels, the second quartile (Q2) (aHRs = 2.40, 95% CI [1.08, 5.35]) of uric acid levels were independently associated with an increased risk of cardiovascular mortality. The RCS model demonstrated a U-shaped pattern in the association between SUA and all-cause mortality in OSA, with an inflection point observed at 5.83 mg/dl. The findings of this study suggest a U-shaped association between serum SUA levels and all-cause mortality and nonlinearity association between serum SUA levels and all-cause mortality. Further studies are warranted to determine the causal relationship between SUA levels and all-cause and cardiovascular mortality.

Association between serum uric acid and prostate cancer mortality in androgen deprivation therapy: A population-based cohort study

OBJECTIVE

This population-based study examined the association between baseline uric acid (UA) and prostate cancer (PCa)-related mortality amongst PCa patients receiving androgen deprivation therapy (ADT).

METHODS

Adults with PCa who received ADT in Hong Kong between December 1999 and March 2021 were identified. Patients with missing baseline UA were excluded. Patients were followed up until September 2021. The outcome was PCa-related mortality.

RESULTS

Altogether, 4126 patients (median follow-up 3.1[interquartile range 1.4-6.0] years) were included. A J-shaped association was observed between baseline UA level and PCa-related mortality risk, with a direct association in those with mean(0.401 mmol/L) or above-mean baseline UA levels (hazard ratio (HR) per standard deviation-increase 1.35 [95% confidence interval 1.21,1.51], p < 0.001), and an inverse association in those with below-mean baseline UA levels (HR 0.78[0.67,0.92], p = 0.003). The former remained significant on competing risk regression, but not the latter.

CONCLUSIONS

A J-shaped relationship between baseline UA level and PCa-related mortality risk was identified. This study was mainly limited by potential unmeasured and residual confounders. Further validation studies are warranted.

Relationship between serum uric acid and estimated glomerular filtration rate in adolescents aged 12-19 years with different body mass indices: a cross-sectional study

Background

Globally, chronic kidney disease (CKD) is a growing public health concern. Serum uric acid (SUA) is an easily detectable and readily available biochemical indicator that has long been recognized as an independent risk factor for CKD. In addition, studies have indicated a potential relationship between SUA and body mass index (BMI). However, studies on the effect of SUA levels on the estimated glomerular filtration rate (eGFR) in adolescents with different BMIs are very rare.

Methods

Weighted multiple regression analysis was used to estimate the independent relationship between SUA and log-transformed eGFR. Additionally, we used a weighted generalized additive model and smooth curve fitting to describe the nonlinear relationships in the subgroup analysis.

Results

First, SUA was negatively associated with log-transformed eGFR even after adjusting for all covariates (β=-0.0177, 95% CI: -0.0203-0.0151, P<0.0001). Second, the results of the stratified analysis found that after adjusting for all covariates, the decrease in log-transformed eGFR due to changes in per SUA levels (Per 1, mg/dL increase) was elevated in female adolescents (β=-0.0177, 95% CI: -0.0216, -0.0138, P<0.0001), adolescents aged 12-15 years (β=-0.0163, 95% CI: -0.0200, -0.0125, P<0.0001) and black (β=-0.0199, 95% CI: -0.0251, -0.0148, P<0.0001) adolescents. Furthermore, we found that adolescents with a higher BMI had higher SUA levels, and the effect of SUA on eGFR was significantly higher in underweight adolescents (β=-0.0386, 95% CI: (-0.0550, -0.0223), P<0.0001).

Conclusion

SUA was negatively associated with the eGFR in adolescents aged 12-19 years. Furthermore, we found for the first time that SUA affects the eGFR differently in adolescents with different BMIs. This effect was particularly significant in underweight adolescents.

U-shaped association of serum uric acid with all-cause mortality in patients with hyperlipidemia in the United States: a cohort study

Background

Serum uric acid (SUA) interferes with lipid metabolism and is considered an independent risk factor for atherosclerosis, a major complication in patients with hyperlipidemia. However, the effects of uric acid levels on mortality in hyperlipidemic patients has yet to be sufficiently determined. In this study, we aimed to assess the association between all-cause mortality and SUA in a hyperlipidemic population.

Methods

To determine mortality rates, we obtained data for 20,038 hyperlipidemia patients from the U.S. National Health and Nutrition Examination Surveys (NHANES) 2001-2018 and National Death Index. To examine the all-cause mortality effect of SUA, multivariable Cox regression models, restricted cubic spline models, and two pairwise Cox regression models were used.

Results

Over a median follow-up of 9.4 years, a total of 2079 deaths occurred. Mortality was examined according to SUA level quintiles: <4.2, 4.3-4.9, 5.0-5.7, 5.8-6.5, and >6.6 mg/dl. In multivariable analysis using 5.8-6.5 mg/dl SUA as a reference, the hazard ratios (95% confidence interval) of all-cause mortality across the five groups were 1.24 (1.06-1.45), 1.19 (1.03-1.38), 1.07 (0.94-1.23), 1.00 (reference), and 1.29 (1.13-1.48), respectively. According to a restricted cubic spline, we noted a U-shaped relationship between SUA and all-cause mortality. The inflection point was approximately 6.30 mg/dl, with hazard ratios of 0.91 (0.85-0.97) and 1.22 (1.10-1.35) to the left and right of the inflection point, respectively. In both sexes, SUA was characterized by a U-shaped association, with inflection points at 6.5 and 6.0 mg/dl for males and females, respectively.

Conclusion

Using nationally representative NHANES data, we identified a U-shaped association between SUA and all-cause mortality in participants with hyperlipidemia.