Gout and the risk of Alzheimer's disease: a population-based, BMI-matched cohort study

D-glucaro-1,4-lactone improves Diethylnitrosamine induced hepatocellular carcinoma in rats via the uric acid-ROS pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Liuwei dihuang pills is a famous Traditional Chinese Medicine with various anti-cancer properties. Over 50 pharmaceutical manufacturers produce Liuwei dihuang pills in China and an estimated millions of people around the world orally take it every day. D-glucaro-1,4-lactone (1,4-GL) was quantified to be about 12.0 mg/g in Liuwei dihuang pills and a primary bioactive component of it inhibiting the activity of β-glucuronidase in vivo. 1,4-GL can prevent and effectively inhibit various types of cancer. However, its exact mechanism of action remains unknown. The study would justify the traditional usage of Liuwei dihuang pills against cancers.

AIM OF THE STUDY

1,4-GL, a bioactive ingredient derived from Liuwei dihuang pills, a famous Traditional Chinese Medicine, could delay the progression of diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats. The mechanism underpinning the effect, however, remains poorly understood.

MATERIALS AND METHODS

Healthy and HCC rats were treated with or without 1,4-GL (40.0 mg/kg) and 1HNMR-based metabonomic analysis was employed. 10 metabolites in uric acid pathway were quantitatively determined by UPLC-MS/MS. The expression of xanthine dehydrogenase (XDH), SLC2A9 mRNA, and SLC2A9 protein was determined using RT-qPCR and Western Blot. The effect of 1,4-GL on HCC-LM3 cells was verified in vitro. The alterations of ROS activity, SLC2A9 and XDH gene levels were observed in NCTC-1469 cells induced by lipopolysaccharide (LPS) after 1,4-GL treatment.

RESULTS

After the intervention of 1,4-GL, improved pathological morphology, liver lesions in HCC rats was observed with restored serum levels of AFP, AST, ALP, γ-GGT and Fisher's ratio. Hepatic metabonomics revealed that puring metabolism were significantly regulated by 1,4-GL in HCC rats. Uric acid, xanthine and hypoxanthine levels were quantified by UPLC-MS/MS and found to be nearly restored to control levels after 1,4-GL treatment in HCC rats. Changes in xanthine oxidase activity, XDH mRNA expression, and SLC2A9 mRNA and protein expression were also reversed. 1,4-GL treatment in LM3 HCC cells were consistent with the results in vivo. Furthermore, oxidative stress indicators such as T-SOD, GSH, CAT and MDA in serum and liver were improved after HCC rats treated with 1,4-GL. In vitro, 1,4-GL was observed to reduce lipopolysaccharide-induced ROS levels in NCTC-1469 cells with enhanced mRNA and protein expression of SLC2A9 and decreased mRNA level of XDH.

CONCLUSION

The protective effects of 1,4-GL against DEN-induced HCC by reducing uric acid and ROS levels due to down-regulation of uric acid production and up-regulation of SLC2A9 expressions. 1,4-GL may represent a novel treatment that improves recovery from HCC by targeting uric acid-ROS pathway.

Biological constraint, evolutionary spandrels and antagonistic pleiotropy

Maximum lifespan differs greatly between species, indicating that the process of senescence is largely genetically determined. Senescence evolves in part due to antagonistic pleiotropy (AP), where selection favors gene variants that increase fitness earlier in life but promote pathology later. Identifying the biological mechanisms by which AP causes senescence is key to understanding the endogenous causes of aging and its attendant diseases. Here we argue that the frequent occurrence of AP as a property of genes reflects the presence of constraint in the biological systems that they specify. This arises particularly because the functionally interconnected nature of biological systems constrains the simultaneous optimization of coupled traits (interconnection constraints), or because individual traits cannot evolve (impossibility constraints). We present an account of aging that integrates AP and biological constraint with recent programmatic aging concepts, including costly programs, quasi-programs, hyperfunction and hypofunction. We argue that AP mechanisms of costly programs and triggered quasi-programs are consequences of constraint, in which costs resulting from hyperfunction or hypofunction cause senescent pathology. Impossibility constraint can also cause hypofunction independently of AP. We also describe how AP corresponds to Stephen Jay Gould's constraint-based concept of evolutionary spandrels, and argue that pathologies arising from AP are bad spandrels. Biological constraint is a conceptual missing link between ultimate and proximate causes of senescence, including diseases of aging.

No causal relationship between serum urate and neurodegenerative diseases: A Mendelian randomization study

OBJECTIVE

Observational studies have shown that increased serum urate is associated with a lower risk of neurodegenerative diseases (NDs), but the causality remains unclear. We employed a two-sample Mendelian randomization (MR) approach to assess the causal relationship between serum urate and four common subtypes of NDs, including Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS).

METHODS

Serum urate data came from the CKDGen Consortium. GWAS data for PD, AD, ALS, and MS were obtained from four databases in the primary analysis and then acquired statistics from the FinnGen consortium for replication and meta-analysis. Inverse variance weighted (IVW), weighted median (WM), and MR-Egger regression methods were applied in the MR analyses. Pleiotropic effects, heterogeneity, and leave-one-out analyses were evaluated to validate the results.

RESULTS

There was no evidence for the effect of serum urate on PD (OR: 1.00, 95 % CI: 0.90-1.11, P = 0.97), AD (OR: 1.02, 95 % CI: 1.00-1.04, P = 0.06), ALS (OR: 1.05, 95 % CI: 0.97-1.13, P = 0.22), and MS (OR: 1.01, 95 % CI: 0.89-1.14, P = 0.90) risk when combined with the FinnGen consortium, neither was any evidence of pleiotropy detected between the instrumental variables (IVs).

CONCLUSION

The MR analysis suggested that serum urate may not be causally associated with a risk of PD, AD, ALS, and MS.

[Association between serum uric acid and airflow obstruction based on the health-checkup population]

OBJECTIVE

To investigate the association between serum uric acid, pulmonary function and airflow obstruction in Chinese Taiwan healthy subjects.

METHODS

All the cross-sectional analysis was performed in the population over 40 years old using the physical examination data of Chinese Taiwan MJ Health Resource Center between 1996 and 2016 stratification by gender. The correlation analyses between serum uric acid were done and multivariate Logistic regression analysis was used to explore the effect of serum uric acid on airflow obstruction.

RESULTS

A total of 35 465 people were included in the study, including 16 411 men and 19 054 women. Among them, the serum uric acid concentration of men was higher than that of women, and the serum uric acid concentration of the people with airflow obstruction was higher than that of the people without airflow obstruction. There was a negative correlation between serum uric acid level and the forced expiratory volume in one second (FEV1) and the force vital capacity (FVC) in women (P < 0.05), but in men the correlation didn' t exist (P>0.05). After adjusting for age, education, smoking status, drinking status, work strength, body mass index, history of cough, history of hypertension, history of diabetes, history of dyslipidemia, white blood cells and blood albumin, the airflow obstruction in women was more likely to exist with the serum uric acid elevated (OR=1. 12, 95%CI: 1.02-1.22, P < 0.05). The results showed that women with hyperuricemia were more likely to have airflow obstruction than those without hyperuricemia (OR=1.36, 95%CI: 1.06-1.75, P < 0.05). There was no correlation between serum uric acid concentration and airflow obstruction in men (OR=1.04, 95%CI: 0.96-1.13, P>0.05), also the hyperuricemia and airflow obstruction (OR=1.12, 95%CI: 0.89-1.39, P>0.05).

CONCLUSION

There is a negative correlation between serum uric acid and FEV1 and FVC in relatively healthy women, and there is an association between elevated serum uric acid and airflow obstruction in women, but not in men. Further prospective studies are needed to explore whether high serum uric acid level can increase the risk of airflow obstruction.

Assessing Risk Factors for Cognitive Decline Using Electronic Health Record Data: A Scoping Review

Background

The data and information contained within electronic health records (EHR) provide a rich, diverse, longitudinal view of real-world patient histories, offering valuable opportunities to study antecedent risk factors for cognitive decline. However, the extent to which such records' data have been utilized to elucidate the risk factors of cognitive decline remains unclear.

Methods

A scoping review was conducted following the PRISMA guideline, examining articles published between January 2010 and April 2023, from PubMed, Web of Science, and CINAHL. Inclusion criteria focused on studies using EHR to investigate risk factors for cognitive decline. Each article was screened by at least two reviewers. Data elements were manually extracted based on a predefined schema. The studied risk factors were classified into categories, and a research gap was identified.

Results

From 1,593 articles identified, 80 were selected. The majority (87.5%) were retrospective cohort studies, with 66.3% using datasets of over 10,000 patients, predominantly from the US or UK. Analysis showed that 48.8% of studies addressed medical conditions, 31.3% focused on medical interventions, and 17.5% on lifestyle, socioeconomic status, and environmental factors. Most studies on medical conditions were linked to an increased risk of cognitive decline, whereas medical interventions addressing these conditions often reduced the risk.

Conclusions

EHR data significantly enhanced our understanding of medical conditions, interventions, lifestyle, socioeconomic status, and environmental factors related to the risk of cognitive decline.

Serum Uric Acid Levels Associated with Outcomes of Neurodegenerative Disorders and Brain Health: Findings from the UK Biobank

BACKGROUND

The relationship between serum uric acid (SUA) levels and brain-related health remains uncertain.

OBJECTIVES

This study aimed to investigate the relationship between SUA levels and some neurodegenerative disorders and brain structure.

DESIGN

A longitudinal study.

SETTING AND PARTICIPANTS

384,517 participants who did not have stroke, dementia, and Parkinsonism, with complete urate testes and covariates were included.

MEASUREMENTS

Cox proportional hazards models, competing risk models, and restricted cubic spine models were applied.

RESULTS

During the median follow-up time of 12.7 years (interquartile range [IQR]:12.0, 13.5), 7821 (2.0%) participants developed stroke, 5103 (1.3%) participants developed dementia, and 2341 (0.6%) participants developed Parkinsonism. Nonlinear relationships were identified between SUA levels and stroke (J-shaped), dementia, and Parkinsonism (U-shaped). SUA levels of 4.2 mg/dl, 6.4 mg/dl, and 6.6 mg/dl yielded the lowest risk of stroke, dementia, and Parkinsonism, respectively. Besides, we found high SUA levels reduced the volumes of total brain, grey matter, white matter, grey matter in the hippocampus, and hippocampus, but increased lateral-ventricle volume. Inflammation accounted for 9.1% and 10.0% in the association of SUA with stroke and lateral-ventricle volume.

CONCLUSIONS

Lower SUA levels increased the risk of Parkinsonism, while both lower and higher SUA levels were positively associated with increased risk of stroke and dementia. Moreover, high SUA levels reduced brain structure volumes. Our findings suggest the association between SUA levels and brain-related disorders and highlight the importance of SUA management.

Uric acid in health and disease: From physiological functions to pathogenic mechanisms

Owing to renal reabsorption and the loss of uricase activity, uric acid (UA) is strictly maintained at a higher physiological level in humans than in other mammals, which provides a survival advantage during evolution but increases susceptibility to certain diseases such as gout. Although monosodium urate (MSU) crystal precipitation has been detected in different tissues of patients as a trigger for disease, the pathological role of soluble UA remains controversial due to the lack of causality in the clinical setting. Abnormal elevation or reduction of UA levels has been linked to some of pathological status, also known as U-shaped association, implying that the physiological levels of UA regulated by multiple enzymes and transporters are crucial for the maintenance of health. In addition, the protective potential of UA has also been proposed in aging and some diseases. Therefore, the role of UA as a double-edged sword in humans is determined by its physiological or non-physiological levels. In this review, we summarize biosynthesis, membrane transport, and physiological functions of UA. Then, we discuss the pathological involvement of hyperuricemia and hypouricemia as well as the underlying mechanisms by which UA at abnormal levels regulates the onset and progression of diseases. Finally, pharmacological strategies for urate-lowering therapy (ULT) are introduced, and current challenges in UA study and future perspectives are also described.

Gout or Hyperuricemia and Dementia Risk: A Meta-Analysis of Observational Studies

Background

As a natural antioxidant, uric acid has neuroprotective effects. The association between uric acid levels and dementia risk was reported by previous studies. However, recently published studies showed that the relationship between uric acid and dementia risk might be heterogeneous in dementia subtypes.

Objective

This study aimed to clarify the relationship between hyperuricemia (or gout) and dementia.

Methods

The PubMed and Web of Science databases were systematically searched up to April 2024 to identify relevant studies. A meta-analysis was conducted using hazard ratios (HR) or odds ratios (OR) and 95% confidence interval (CI) as pooled indicators. Heterogeneity between the studies was examined using Cochran's Q statistic and I2 statistic. Subgroup analyses were conducted for gender and age. Stratification analysis, sensitivity analyses and meta-regression were conducted to explore possible explanations for heterogeneity. Publication bias was assessed by funnel plot and Egger's test.

Results

A total of 11 studies met the inclusion criteria including 2,928,152 participants were abstracted. Hyperuricemia (or gout) did not reduce the overall risk of dementia (OR/HR = 0.92, 95% CI: 0.81-1.05) and vascular dementia (OR/HR = 0.74, 95% CI: 0.53-1.05), but may have a protective effect against Alzheimer's disease (OR/HR = 0.82, 95% CI: 0.70-0.96). Subgroup analysis showed that a lower risk of dementia was observed in men (OR/HR = 0.83, 95% CI: 0.77-0.90) and patients whose age under 65 (OR/HR = 0.83, 95% CI: 0.72-0.95).

Conclusions

Patients with gout or hyperuricemia have a low risk of Alzheimer's disease.

Dysuricemia

Gout results from elevated serum urate (SU) levels, or hyperuricemia, and is a globally widespread and increasingly burdensome disease. Recent studies have illuminated the pathophysiology of gout/hyperuricemia and its epidemiology, diagnosis, treatment, and complications. The genetic involvement of urate transporters and enzymes is also proven. URAT1, a molecular therapeutic target for gout/hyperuricemia, was initially derived from research into hereditary renal hypouricemia (RHUC). RHUC is often accompanied by complications such as exercise-induced acute kidney injury, which indicates the key physiological role of uric acid. Several studies have also revealed its physiological role as both an anti-oxidant and a pro-oxidant, acting as both a scavenger and a generator of reactive oxygen species (ROSs). These discoveries have prompted research interest in SU and xanthine oxidoreductase (XOR), an enzyme that produces both urate and ROSs, as status or progression biomarkers of chronic kidney disease and cardiovascular disease. The notion of "the lower, the better" is therefore incorrect; a better understanding of uric acid handling and metabolism/transport comes from an awareness that excessively high and low levels both cause problems. We summarize here the current body of evidence, demonstrate that uric acid is much more than a metabolic waste product, and finally propose the novel disease concept of "dysuricemia" on the path toward "normouricemia", or optimal SU level, to take advantage of the dual roles of uric acid. Our proposal should help to interpret the spectrum from hypouricemia to hyperuricemia/gout as a single disease category.

Association of visceral adipose tissue with gout: Observational and Mendelian randomization analyses

BACKGROUND

The causal relationship between visceral adipose tissue (VAT) and gout is still unclear. We aimed to examine the potential association between them using observational and Mendelian randomization (MR) analyses.

METHODS

In the observational analyses, a total of 11,967 participants (aged 39.5 ± 11.5 years) were included from the National Health and Nutrition Examination Survey. Logistic regression models were used to investigate the association between VAT mass and the risk of gout. In two-sample MR analyses, 211 VAT mass-related independent genetic variants (derived from genome-wide association studies in 325,153 UK biobank participants) were used as instrumental variables. The random-effects inverse-variance weighted (IVW) method was used as the primary analysis. Additional sensitivity analyses were also performed to validate our results.

RESULTS

Observational analyses found that an increase in VAT mass (per standard deviation) was associated with a higher risk of gout after controlling for confounding factors (odds ratio [OR] = 1.27, 95% confidence intervals [CI] = 1.11-1.45). The two-sample MR analyses demonstrated a causal relationship between increased VAT mass and the risk of gout in primary analyses (OR = 1.78, 95% CI = 1.57-2.03). Sensitivity analyses also showed similar findings, including MR-Egger, weighted median, simple mode, weighted mode, and leave-one-out analyses.

CONCLUSIONS

Observational analyses showed a robust association of VAT mass with the risk of gout. Meanwhile, MR analyses also provided evidence of a causal relationship between them. In summary, our findings suggested that targeted interventions for VAT mass may be beneficial to prevent gout.

The Role of Uric Acid in Human Health: Insights from the Uricase Gene

Uric acid is the final product of purine metabolism and is converted to allantoin in most mammals via the uricase enzyme. The accumulation of loss of function mutations in the uricase gene rendered hominoids (apes and humans) to have higher urate concentrations compared to other mammals. The loss of human uricase activity may have allowed humans to survive environmental stressors, evolution bottlenecks, and life-threatening pathogens. While high urate levels may contribute to developing gout and cardiometabolic disorders such as hypertension and insulin resistance, low urate levels may increase the risk for neurodegenerative diseases. The double-edged sword effect of uric acid has resurrected a growing interest in urate's antioxidant role and the uricase enzyme's role in modulating the risk of obesity. Characterizing both the effect of uric acid levels and the uricase enzyme in different animal models may provide new insights into the potential therapeutic benefits of uric acid and novel uricase-based therapy.

Uric acid and neurological disease: a narrative review

Hyperuricemia often accompanies hypertension, diabetes, dyslipidemia, metabolic syndrome, and chronic renal disease; it is also closely related to cardiovascular disease. Moreover, several epidemiological studies have linked hyperuricemia and ischemic stroke. However, uric acid may also have neuroprotective effects because of its antioxidant properties. An association between low uric acid levels and neurodegenerative diseases has been suggested, which may be attributed to diminished neuroprotective effects as a result of reduced uric acid. This review will focus on the relationship between uric acid and various neurological diseases including stroke, neuroimmune diseases, and neurodegenerative diseases. When considering both the risk and pathogenesis of neurological diseases, it is important to consider the conflicting dual nature of uric acid as both a vascular risk factor and a neuroprotective factor. This dual nature of uric acid is important because it may help to elucidate the biological role of uric acid in various neurological diseases and provide new insights into the etiology and treatment of these diseases.

Biometals in Alzheimer disease: emerging therapeutic and diagnostic potential of molybdenum and iodine

The current ageing trend of the world population has, in part, accounted for Alzheimer disease (AD) being a public health issue in recent times. Although some progress has been made in clarifying AD-related pathophysiological mechanisms, effective intervention is still elusive. Biometals are indispensable to normal physiological functions of the human body-for example, neurogenesis and metabolism. However, their association with AD remains highly controversial. Copper (Cu) and zinc (Zn) are biometals that have been investigated at great length in relation to neurodegeneration, whereas less attention has been afforded to other trace biometals, such as molybdenum (Mo), and iodine. Given the above context, we reviewed the limited number of studies that have evidenced various effects following the usage of these two biometals in different investigative models of AD. Revisiting these biometals via thorough investigations, along with their biological mechanisms may present a solid foundation for not only the development of effective interventions, but also as diagnostic agents for AD.

Gout and risk of dementia, Alzheimer's disease or vascular dementia: a meta-epidemiology study

Objectives

The association between gout and dementia, Alzheimer's disease (AD), or vascular dementia (VD) is not fully understood. The aim of this meta-analysis was to evaluate the risk of all-cause dementia, AD, and VD in gout patients with or without medication.

Methods

Data sources were PubMed, Embase, the Cochrane Library, and reference lists of included studies. This meta-analysis included cohort studies assessing whether the risk of all-cause dementia, AD, and VD was associated with gout. The risk of bias was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to access the overall certainty of evidence. Risk ratios (RR) with 95% confidence intervals (CI) were pooled using a random-effects model, and publication bias was assessed with funnel plots and Egger's test.

Results

A total of six cohort studies involving 2,349,605 individuals were included in this meta-analysis, which were published between 2015 and 2022. The pooling analysis shows that the risk of all-cause dementia was decreased in gout patients [RR = 0.67, 95% CI (0.51, 0.89), I2 = 99%, P = 0.005, very low quality], especially in gout patients with medication [RR = 0.50, 95% CI (0.31, 0.79), I2 = 93%, P = 0.003, low quality]. The risk of AD [RR = 0.70, 95% CI (0.63, 0.79), I2 = 57.2%, P = 0.000, very low quality] and VD [RR = 0.68, 95% CI (0.49, 0.95), I2 = 91.2%, P = 0.025, very low quality] was also decreased in gout patients. Despite the large heterogeneity, the sensitivity analysis indicated that the results were robust, and there was little evidence of publication bias.

Conclusion

The risk of all-cause dementia, AD, and VD is decreased in gout patients, but the quality of evidence is generally low. More studies are still needed to validate and explore the mechanisms of this association.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022353312.

Dysuricemia-A New Concept Encompassing Hyperuricemia and Hypouricemia

The importance of uric acid, the final metabolite of purines excreted by the kidneys and intestines, was not previously recognized, except for its role in forming crystals in the joints and causing gout. However, recent evidence implies that uric acid is not a biologically inactive substance and may exert a wide range of effects, including antioxidant, neurostimulatory, proinflammatory, and innate immune activities. Notably, uric acid has two contradictory properties: antioxidant and oxidative ones. In this review, we present the concept of "dysuricemia", a condition in which deviation from the appropriate range of uric acid in the living body results in disease. This concept encompasses both hyperuricemia and hypouricemia. This review draws comparisons between the biologically biphasic positive and negative effects of uric acid and discusses the impact of such effects on various diseases.

n-3 PUFA poor seafood consumption is associated with higher risk of gout, whereas n-3 PUFA rich seafood is not: NHANES 2007–2016

Background and aims

Gout, the most prevalent inflammatory arthritis, has undesirable effects on the quality of life. Omega-3 polyunsaturated fatty acids (n-3 PUFA) has a strong link with anti-inflammatory impacts. However, whether the harmful effects of seafood in relation to gout may vary owing to different levels of n-3 PUFA in seafood is still unclear. It was the goal of this study to examine the relationship between n-3 PUFA poor/rich seafood consumption and gout.

Methods

Between 2007 and 2016, five NHANES cycles were performed, with 12,505 subjects having complete data for gout and two 24-h dietary intake interviews. The 24-h dietary recalls were utilized to evaluate dietary habits. Gout was defined based on questionnaires. Weighted logistic regression models were conducted to investigate the association between n-3 PUFA poor/rich seafood consumption and gout. Moreover, subgroup analysis was utilized to estimate the stability of results. Covariates including age, gender, race/ethnicity, income, education, body mass index, chronic kidney disease, diabetes mellitus, hypertension, smoking status, and drinking status were stratified in different models.

Results

In the fully adjusted model, each unit of increase of n-3 PUFA poor seafood intake was associated with an 8.7% increased risk of gout (OR = 1.087, 95% CI: 1.039, 1.138, P &lt; 0.001), whereas, no correlation was found between n-3 PUFA rich seafood consumption and gout. It also provided a proof-of-concept regarding the potential for n-3 PUFA rich seafood to counteract harmful effects of purines in relation to gout. A dose-response analysis showed that there was a non-linear relationship between n-3 PUFA rich seafood intake and the risk of gout in the female group.

Conclusion

Findings suggest that n-3 PUFA poor seafood consumption is associated with higher risk of gout, whereas n-3 PUFA rich seafood is not.

Association between gout at midlife and cognitive impairment at late life - The Singapore Chinese Health Study

OBJECTIVES

The association between gout and risk of cognitive impairment or dementia is not well established. We examined the relationship between having gout at midlife and the risk of developing cognitive impairment later on.

METHODS

We used data of 16,948 participants from the population-based Singapore Chinese Health Study cohort. Participants were recruited from 1993 to 1998 at mean age of 53 years and re-contacted for three follow-up interviews: 1999 to 2004 for follow-up 1, 2006 to 2010 for follow-up 2, and 2014 to 2016 for follow-up 3. History of physician-diagnosed gout was self-reported at follow-up 1 and follow-up 2, while cognitive function was assessed with the Singapore modified Mini-Mental State Examination during follow-up 3, when participants had a mean age of 73.2 years.

RESULTS

Gout was reported by 1281 (7.6%) participants at either follow-up 1 or 2, and 2243 (14.4%) had cognitive impairment at follow-up 3. A history of gout was associated with reduced risk of cognitive impairment (OR 0.78, 95% CI 0.65-0.93). This risk was reduced in a stepwise manner with either increased duration of gout or lower age at first diagnosis of gout (P_trend <0.001). Compared to those without gout, those with gout for ≥20 years (OR 0.56, 95% CI 0.39-0.80) and those with age of onset of gout <50 years old (OR 0.59, 95% CI 0.37-0.94) had a lower risk of developing cognitive impairment.

CONCLUSION

A young age of onset or a long history of gout was associated with reduced risk of cognitive impairment in late life.

Longitudinal follow-up study of the association with gout and Alzheimer's disease and Parkinson's disease in Korea

To date, no clear conclusion on the relationships of gout with the occurrence of typical neurodegenerative diseases, Alzheimer's disease (AD) and Parkinson's disease (PD), has been reached. This study aimed to determine whether the patients with gout are at a lower or higher probability of developing AD or PD than those without gout. Longitudinal follow-up data of a representative sample of Korean adults were assessed. 18,079 individuals diagnosed with gout between 2003 and 2015 were enrolled in the gout group. The comparison group comprised 72,316 demographics-matched individuals not diagnosed with gout. Longitudinal associations of gout with AD or PD were estimated using Cox proportional hazard regression adjusting for potential confounders. The adjusted hazard ratios (HRs) of AD and PD in the gout group were 1.01 and 1.16 times higher than controls, but these differences were not statistically significant (95% confidence interval [CI] = 0.92-1.12 and 95% CI = 0.97-1.38, respectively). Although there was no significant association in the entire sample, AD and PD probabilities in patients with gout were significantly higher in participants < 60 years, and PD probabilities in patients with gout were significantly higher in overweight participants. Our findings identify significant correlations of gout with AD and PD in participants < 60 years and gout with PD in those with overweight, indicating that gout may play a role in the development of neurodegenerative diseases in younger or overweight populations. Further investigations should be performed to corroborate these findings.

Prevalence of motor neuron diseases in gout patients: a nationwide population-based cohort study

BACKGROUND

Increased uric acid may have a protective effect in motor neuron diseases (MNDs). The association between gout, characterized by hyperuricemia, and MNDs was not investigated previously. To estimate the prevalence of MNDs in gout patients using the Health Insurance and Review Assessment (HIRA) database, a nationwide database of South Korea.

METHODS

The current descriptive study was conducted using the HIRA database. Subjects diagnosed with gout from 2011 to 2018 were included in this study. Among them, the annual prevalence of MNDs was analyzed, stratified by age and sex. Comorbidities including the Charlson Comorbidity Index score and type of prescribed gout-related drug were also demonstrated.

RESULTS

The age-adjusted prevalence of MNDs per 10⁵ persons ranged from 0.598 (95% confidence interval (CI): - 0.231-1.426) to 2.534 (95% CI: 1.100-3.968) between 2011 and 2018. Compared to previous reports, the prevalence of MNDs, especially amyotrophic lateral sclerosis (ALS), in gout patients was significantly lower than in the general population. None of the female gout patients were diagnosed with MNDs. Cerebrovascular accidents, vascular risk factors including hypertension, dyslipidemia, and diabetic complications, and the use of uric acid-lowering agents were more common in gout patients with MNDs than in those without MNDs.

CONCLUSION

This study adds to the evidence of MND prevalence in gout patients. Gout might have a protective effect against the risk of MNDs.

Biologic targets of prescription medications and risk of neurodegenerative disease in United States Medicare beneficiaries

OBJECTIVE

To identify prescription medications associated with a lower risk of three neurodegenerative diseases: Parkinson disease, Alzheimer disease, and amyotrophic lateral sclerosis.

METHODS

We conducted a population-based, case-control study of U.S. Medicare beneficiaries in 2009 (42,885 incident neurodegenerative disease cases, 334,387 randomly selected controls). Using medication data from 2006-2007, we categorized all filled medications according to their biological targets and mechanisms of action on those targets. We used multinomial logistic regression models, while accounting for demographics, indicators of smoking, and health care utilization, to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for 141 target-action pairs and each neurodegenerative disease. For target-action pairs inversely associated with all three diseases, we attempted replication in a cohort study that included an active comparator group. We constructed the cohort by following controls forward for incident neurodegenerative disease from the beginning of 2010 until death or end of 2014, i.e., up to five years after the two-year exposure lag. We used Cox proportional hazards regression while accounting for the same covariates.

RESULTS

The most consistent inverse association across both studies and all three neurodegenerative diseases was for xanthine dehydrogenase/oxidase blockers, represented by the gout medication, allopurinol. Allopurinol was associated with a 13-34% lower risk for each neurodegenerative disease group in multinomial regression, and a mean reduction of 23% overall, as compared to individuals who did not use allopurinol. In the replication cohort we observed a significant 23% reduction for neurodegenerative disease in the fifth year of follow-up, when comparing allopurinol users to non-users, and more marked associations with an active comparator group. We observed parallel associations for a related target-action pair unique to carvedilol.

DISCUSSION/CONCLUSION

Xanthine dehydrogenase/oxidase blockade might reduce risk of neurodegenerative disease. However, further research will be necessary to confirm that the associations related to this pathway are causal or to examine whether this mechanism slows progression.

Gout and the Prevalence of Dementia: A Nationwide Population-Based Study

BACKGROUND

Hyperuricemia in patients with gout is associated with a low risk of neurodegenerative diseases, including dementia. However, the prevalence of dementia in patients with gout has not yet been reported.

OBJECTIVE

To analyze the prevalence of dementia among patients diagnosed with gout by utilizing the Health Insurance and Review Assessment database, a nationwide registry of the South Korean population.

METHODS

Data from the Health Insurance and Review Assessment database of patients diagnosed with gout between 2011 and 2018 were extracted. The annual prevalence of dementia according to age and sex was analyzed. We investigated whether there was an association between comorbidities and gout medication in patients with both gout and dementia and in patients with only gout.

RESULTS

Between 2011 and 2018, the age-adjusted prevalence of dementia per 100,000 persons ranged from 54.0 (95% confidence interval: 47.7-60.2) to 69.9 (95% confidence interval: 65.3-74.5). Compared to previous studies, the prevalence of dementia was lower in patients with gout than in the general population. Patients with both gout and dementia were more likely to be women, have a wide range of comorbidities, and be prescribed gout-related drugs, including allopurinol, febuxostat, nonsteroidal anti-inflammatory drugs, and steroids than patients with gout without dementia.

CONCLUSIONS

This study demonstrated a relatively low prevalence of dementia in patients with gout. Gout, characterized by hyperuricemia, might be associated with a reduced risk of dementia.

Phenotype-based screening rediscovered benzopyran-embedded microtubule inhibitors as anti-neuroinflammatory agents by modulating the tubulin-p65 interaction

Neuroinflammation is one of the critical processes implicated in central nervous system (CNS) diseases. Therefore, alleviating neuroinflammation has been highlighted as a therapeutic strategy for treating CNS disorders. However, the complexity of neuroinflammatory processes and poor drug transport to the brain are considerable hurdles to the efficient control of neuroinflammation using small-molecule therapeutics. Thus, there is a significant demand for new chemical entities (NCEs) targeting neuroinflammation. Herein, we rediscovered benzopyran-embedded tubulin inhibitor 1 as an anti-neuroinflammatory agent via phenotype-based screening. A competitive photoaffinity labeling study revealed that compound 1 binds to tubulin at the colchicine-binding site. Structure-activity relationship analysis of 1's analogs identified SB26019 as a lead compound with enhanced anti-neuroinflammatory efficacy. Mechanistic studies revealed that upregulation of the tubulin monomer was critical for the anti-neuroinflammatory activity of SB26019. We serendipitously found that the tubulin monomer recruits p65, inhibiting its translocation from the cytosol to the nucleus and blocking NF-κB-mediated inflammatory pathways. Further in vivo validation using a neuroinflammation mouse model demonstrated that SB26019 suppressed microglial activation by downregulating lba-1 and proinflammatory cytokines. Intraperitoneal administration of SB26019 showed its therapeutic potential as an NCE for successful anti-neuroinflammatory regulation. Along with the recent growing demands on tubulin modulators for treating various inflammatory diseases, our results suggest that colchicine-binding site-specific modulation of tubulins can be a potential strategy for preventing neuroinflammation and treating CNS diseases.

Elevated serum uric acid is associated with cognitive improvement in older American adults: A large, population-based-analysis of the NHANES database

Background

The many studies revealing a connection between serum uric acid (SUA) and dementia have reported conflicting results. This study sought to investigate the relations between SUA and cognitive function in older adults.

Materials and methods

The sample was 2,767 American adults aged ≥60 years from the National Health and Nutrition Examination Survey 2011-2014. Cognitive performance was evaluated by the Consortium to Establish a Registry for Alzheimer's Disease test, animal fluency test, digit symbol substitution test, and composite z-score. Multivariate linear regression analyses were conducted to estimate the association between SUA and cognitive function.

Results

SUA level and cognitive function were significantly, positively correlated. Age significantly correlated with the association between SUA and cognitive function.

Conclusion

These findings support a connection between SUA and cognition, showing a positive link between SUA and cognitive scores among older American adults. We contend that a slight rise in uric acid within the normal range is advantageous for enhanced cognition. To confirm the precise dose-time-response relation, more tests will be needed.

Association between urate-lowering therapies and cognitive decline in community-dwelling older adults

Long-term use of urate-lowering therapies (ULT) may reduce inflammaging and thus prevent cognitive decline during aging. This article examined the association between long-term use of ULT and cognitive decline among community-dwelling older adults with spontaneous memory complaints. We performed a secondary observational analysis using data of 1673 participants ≥ 70 years old from the Multidomain Alzheimer Preventive Trial (MAPT Study), a randomized controlled trial assessing the effect of a multidomain intervention, the administration of polyunsaturated fatty acids (PUFA), both, or placebo on cognitive decline. We compared cognitive decline during the 5-year follow-up between three groups according to ULT (i.e. allopurinol and febuxostat) use: participants treated with ULT during at least 75% of the study period (PT ≥ 75; n = 51), less than 75% (PT < 75; n = 31), and non-treated participants (PNT; n = 1591). Cognitive function (measured by a composite score) was assessed at baseline, 6 months and every year for 5 years. Linear mixed models were performed and results were adjusted for age, sex, body mass index (BMI), diagnosis of arterial hypertension or diabetes, baseline composite cognitive score, and MAPT intervention groups. After the 5-year follow-up, only non-treated participants presented a significant decline in the cognitive composite score (mean change - 0.173, 95%CI - 0.212 to - 0.135; p < 0.0001). However, there were no differences in change of the composite cognitive score between groups (adjusted between-group difference for PT ≥ 75 vs. PNT: 0.144, 95%CI - 0.075 to 0.363, p = 0.196; PT < 75 vs. PNT: 0.103, 95%CI - 0.148 to 0.353, p = 0.421). Use of ULT was not associated with reduced cognitive decline over a 5-year follow-up among community-dwelling older adults at risk of dementia.

Higher HEI-2015 scores are associated with lower risk of gout and hyperuricemia: Results from the national health and nutrition examination survey 2007-2016

Gout, the most prevalent inflammatory arthritis, is becoming increasingly prevalent in the United States and across the world, and it adversely impacts people’s quality of life and their health. Few studies have focused on the relationship between daily dietary quality and gout, so the topic requires further exploration. Data were derived from the National Health and Nutrition Examination Survey 2007–2016, and the inclusion criteria of the analytic sample were (1) adults, age ≥20 years, with complete information about HEI-2015, gout, and uric acid; (2) complete information of demographics, lifestyle (BMI, smoking, drinking), and disease history [hypertension, chronic kidney disease (CKD), diabetes]. The quality of the daily diet was reflected using the Healthy Eating Index 2015 (HEI-2015). The baseline features of different groups were examined using the Scott-Rao chi-square tests, and the association between the HEI-2015 score and the risk of gout/hyperuricemia (HUA) was investigated using weighted logistic regression models. The effects of different dietary components in the HEI-2015 on reducing the risk of gout/HUA were evaluated by weighted quantile sum (WQS) regression models. After adjusting for demographic characteristics, behavioral covariates, and disease history, higher HEI-2015 scores were associated with a significantly lower risk of gout (OR: 0.878, 95% CI: 0.876–0.880) and HUA (OR: 0.978, 95% CI: 0.976–0.979) in weighted logistic regression. Dairy, whole grains, plant proteins, and added sugar contributed greatly in HEI-2015 to reducing gout risk (weights of WQS index: 42, 17.18, 16.13, and 7.93%, respectively). Dairy, total fruits, greens and beans, and plant proteins contributed greatly in HEI-2015 to reducing HUA risk (weights of WQS index: 28.9, 17.13, 16.84, and 11.39%, respectively). As the result, adherence to the American Dietary Guidelines may assist to decrease the risk of gout/HUA in American adults, and greater emphasis should be placed on dairy products, whole grains, fruits, legumes, and added sugars.

The Association of Serum Uric Acid Level, Gout, and Alzheimer's Disease: A Bidirectional Mendelian Randomization Study

BACKGROUND

The relationship between serum uric acid (UA) and Alzheimer's disease (AD) risk still remained ambiguous despite extensive attempts.

OBJECTIVE

Via the two-sample Mendelian randomization (MR) design, we aimed to examine the bidirectional causal relationships of serum UA, gout, and the risk of AD.

METHODS

Genetic variants of UA, gout, and AD were extracted from published genome-wide association summary statistics. The inverse-variance weighted (IVW, the primary method), and several sensitivity methods (MR-Egger, weighted median, and weighted mode) were used to calculate the effect estimates. Egger regression, MR-PRESSO and leave-one-SNP-out analysis were performed to identify potential violations.

RESULTS

Genetic proxies for serum UA concentration [odds ratio (ORIVW) = 1.09, 95% confidence interval (CI) = 1.01-1.19, p = 0.031] were related with an increased risk of AD using 25 single nucleotide polymorphisms (SNPs). This causal effect was confirmed by sensitivity analyses including MR-Egger (1.22, 1.06-1.42, p = 0.014), weighted median (1.18, 1.05-1.33, p = 0.006), and weighted mode (1.20, 1.07-1.35, p = 0.005) methods. No evidence of notable directional pleiotropy and heterogeneity were identified (p >  0.05). Three SNPs (rs2078267, rs2231142, and rs11722228) significantly drove the observed causal effects. Supportive causal effect of genetically determined gout on AD risk was demonstrated using two SNPs (ORIVW = 1.05, 95% CI = 1.00-1.11, p = 0.057). No reverse causal effects of AD on serum UA levels and gout risk were found.

CONCLUSION

The findings revealed a causal relationship between elevated serum UA level and AD risk. However, further research is still warranted to investigate whether serum UA could be a reliable biomarker and therapeutic target for AD.

The association of serum uric acid with cognitive impairment and ATN biomarkers

Background

Cognitive impairment (CI) has become a worldwide health problem. The relationship between CI and uric acid (UA) is contradictory.

Objective

We included participants with a full spectrum of CI, from cognitively unimpaired (CU) to dementia, from the Chongqing Ageing & Dementia Study (CADS).

Methods

First, we identified the relationships between serum UA (sUA) and cognitive function in different stages of CI. Second, we analyzed these relationships among different stages and types of CI. Finally, we explored the association between sUA and amyloid/tangle/neurodegeneration (ATN) biomarkers.

Results

We recruited 427 participants from the CADS, including 382 participants with mini-mental state examination (MMSE) evaluation. The levels of sUA were positively correlated with MMSE scores (p < 0.001), and the correlation was prominent in the course of dementia and in the type of Alzheimer’s disease (AD). The levels of UA had a positive correlation with plasma amyloid-β 42 (Aβ42) (p = 0.004). Higher levels of sUA weakened the correlation of MMSE scores with CSF ATN biomarkers and the correlation of CSF Aβ42 with tau.

Conclusion

UA is positively correlated with cognitive function, especially in the advanced stage of AD. The probable neuroprotective effects of sUA mainly act on Aβ42 and the downstream pathological cascade.

Reference range of serum uric acid and prevalence of hyperuricemia: a cross-sectional study from baseline data of ELSA-Brasil cohort

Background

Most of the few studies that have established reference ranges for serum uric acid (SUA) have not taken into account factors which may interfere with its levels and followed rigorous laboratory quality standards. The aim of this study was to establish reference ranges for SUA and determine the prevalence of hyperuricemia.

Method

Cross-sectional study including 15,100 participants (all sample) aged 35 to 74 years from baseline data of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicentric cohort of volunteer civil servants from five universities and one research institute located in different regions of Brazil. It was established a reference sample excluding participants with factors that directly influence SUA levels: glomerular filtration rate lower than 60 ml/min, excessive alcohol intake, use of diuretics, aspirin, estrogen or urate-lowering therapy. SUA was measured using the uricase method and following rigorous international quality standards. Reference ranges were defined as values between percentiles 2.5 (P2.5) and 97.5 (P97.5) of SUA distribution in the reference sample, stratified by sex. Hyperuricemia was defined as SUA ≥ 7 mg/100 ml in the all sample.

Results

The reference sample was composed of 10,340 individuals (55.3% women, median age 50 years). Reference ranges (P2.5 to P97.5) for SUA were: 4.0 to 9.2 mg/100 ml for men and 2.8 to 6.9 mg/100 ml for women. Sex was a major determinant for SUA levels (median [IQR], mg/100 ml: 6.1 [5.3–7.0] for men versus 4.5 [3.9–5.3] for women, p < 0.001). Higher levels of SUA were found in patients with higher BMI. Higher age had (a modest) influence only for women. The prevalence of hyperuricemia for all sample (N = 15,100) was 31.9% (95% confidence interval [CI] 30.8–33.0%) in men and 4.8% (95% CI 4.3–5.3%) in women.

Conclusion

SUA reference ranges were 4.0 to 9.2 mg/100 ml for men and 2.8 to 6.9 mg/100 ml for women. Prevalence of hyperuricemia was 31.9% in men and 4.8% in women. Updated SUA reference ranges and prevalence of hyperuricemia are higher nowadays and might be used to guide laboratories and the screening for diseases related to SUA.

Body surface area affected by psoriasis and the risk for psoriatic arthritis: a prospective population-based cohort study

OBJECTIVE

Increasing psoriasis severity has been associated with comorbidities including cardiovascular disease. The objective of this study was to examine the association of psoriasis severity with the development of PsA.

METHODS

A prospective population-based cohort study was performed within The Health Improvement Network, a UK medical record database. Patients aged 25-60 years with a code for psoriasis were randomly selected between 2008 and 2011. Questionnaires were sent to their general practitioners to confirm the diagnosis of psoriasis and provide the patient's approximate body surface area (BSA). Incidence of PsA was calculated by BSA, and Cox proportional hazard ratios were used to examine the risk of developing PsA by BSA category after adjusting for other covariates.

RESULTS

Among 10 474 questionnaires sent, 9987 (95%) were returned, 9069 (91%) had confirmed psoriasis, and BSA was provided for 8881 patients: 52% had mild psoriasis, 36% moderate psoriasis and 12% severe psoriasis. The mean age was 46, and 49% were female. Mean follow-up time was 4.2 years (s.d. 2.1); the incidence of PsA was 5.4 cases per 1000 person-years. After adjusting for age and sex, BSA >10% [hazard ratio (HR) 2.01, 95% CI: 1.29, 3.13], BSA 3-10% (HR 1.44, 95% CI: 1.02, 2.03), obesity (HR 1.64, 95% CI: 1.19, 2.26) and depression (HR 1.68, 95% CI: 1.21, 2.33) were associated with incident PsA.

CONCLUSIONS

In this large prospective cohort study, BSA assessed by general practitioners was a strong predictor of developing PsA, and obesity and depression were additive risk factors.

Uric Acid and Oxidative Stress-Relationship with Cardiovascular, Metabolic, and Renal Impairment

Background: The connection between uric acid (UA) and renal impairment is well known due to the urate capacity to precipitate within the tubules or extra-renal system. Emerging studies allege a new hypothesis concerning UA and renal impairment involving a pro-inflammatory status, endothelial dysfunction, and excessive activation of renin–angiotensin–aldosterone system (RAAS). Additionally, hyperuricemia associated with oxidative stress is incriminated in DNA damage, oxidations, inflammatory cytokine production, and even cell apoptosis. There is also increasing evidence regarding the association of hyperuricemia with chronic kidney disease (CKD), cardiovascular disease, and metabolic syndrome or diabetes mellitus. Conclusions: Important aspects need to be clarified regarding hyperuricemia predisposition to oxidative stress and its effects in order to initiate the proper treatment to determine the optimal maintenance of UA level, improving patients’ long-term prognosis and their quality of life.

Phenome-Wide Association Study of Polygenic Risk Score for Alzheimer's Disease in Electronic Health Records

Alzheimer's disease (AD) is the most common form of dementia and a growing public health burden in the United States. Significant progress has been made in identifying genetic risk for AD, but limited studies have investigated how AD genetic risk may be associated with other disease conditions in an unbiased fashion. In this study, we conducted a phenome-wide association study (PheWAS) by genetic ancestry groups within a large academic health system using the polygenic risk score (PRS) for AD. PRS was calculated using LDpred2 with genome-wide association study (GWAS) summary statistics. Phenotypes were extracted from electronic health record (EHR) diagnosis codes and mapped to more clinically meaningful phecodes. Logistic regression with Firth's bias correction was used for PRS phenotype analyses. Mendelian randomization was used to examine causality in significant PheWAS associations. Our results showed a strong association between AD PRS and AD phenotype in European ancestry (OR = 1.26, 95% CI: 1.13, 1.40). Among a total of 1,515 PheWAS tests within the European sample, we observed strong associations of AD PRS with AD and related phenotypes, which include mild cognitive impairment (MCI), memory loss, and dementias. We observed a phenome-wide significant association between AD PRS and gouty arthropathy (OR = 0.90, adjusted p = 0.05). Further causal inference tests with Mendelian randomization showed that gout was not causally associated with AD. We concluded that genetic predisposition of AD was negatively associated with gout, but gout was not a causal risk factor for AD. Our study evaluated AD PRS in a real-world EHR setting and provided evidence that AD PRS may help to identify individuals who are genetically at risk of AD and other related phenotypes. We identified non-neurodegenerative diseases associated with AD PRS, which is essential to understand the genetic architecture of AD and potential side effects of drugs targeting genetic risk factors of AD. Together, these findings expand our understanding of AD genetic and clinical risk factors, which provide a framework for continued research in aging with the growing number of real-world EHR linked with genetic data.

Hyperuricemia, Gout, and the Brain-an Update

PURPOSE OF REVIEW

This review aims to summarize recent evidence regarding the complex relationship between uric acid (UA), gout, and brain diseases.

RECENT FINDINGS

Observational studies have suggested that patients with hyperuricemia or gout might have a decreased risk of neurodegenerative diseases. Conversely, they may be at increased risk of cerebrovascular disease. Mendelian randomization (MR) studies use a genetic score as an instrumental variable to address the causality of the association between a risk factor (here, UA or gout) and an outcome. So far, MR analyses do not support a causal relationship of UA or gout with Alzheimer's disease and dementia, and of UA with Parkinson's disease or stroke. Observation studies indicate a U-shaped association between UA and brain diseases, but MR studies do not support that this association is causal. Further studies should address the causal role of gout as well as the impact of urate-lowering therapy on these outcomes.

Association Between Gout and Dementia in the Elderly: A Nationwide Population-Based Cohort Study

OBJECTIVE

The data showing the association between gout and dementia are inconsistent. The objective of this study was to examine whether gout is associated with the risk of dementia in the elderly.

METHODS

This retrospective cohort study used population-based representative claims data from the National Health Insurance Service in Korea. We used the Elderly Cohort database which represents 10% of the elderly Koreans over the age of 60, from 2002 to 2013. We assessed the association of gout with a new diagnosis of dementia with Cox proportional hazard models and adjusted the data for potential covariates such as demographics (age, sex) and comorbidities.

RESULTS

We included 22,178 patients with gout and 113,590 without. In each group, 2,557 (11.53%) and 18,264 (16.08%) patients, respectively, had dementia. In multivariable analyses, gout was independently associated with a significantly lower hazard ratio of incident dementia, with an adjusted hazard ratio of 0.63 (95% CI, 0.60-0.66). A sub-group analysis conducted to find out the effects of gout medication showed that febuxostat use significantly decreased incident dementia.

CONCLUSION

Gout was independently associated with a 37% lower risk of dementia in the elderly.

High Blood Uric Acid Is Associated With Reduced Risks of Mild Cognitive Impairment Among Older Adults in China: A 9-Year Prospective Cohort Study

Background: It remains unsolved that whether blood uric acid (UA) is a neuroprotective or neurotoxic agent. This study aimed to evaluate the longitudinal association of blood UA with mild cognitive impairment (MCI) among older adults in China.

Methods: A total of 3,103 older adults (aged 65+ years) free of MCI at baseline were included from the Healthy Aging and Biomarkers Cohort Study (HABCS). Blood UA level was determined by the uricase colorimetry assay and analyzed as both continuous and categorical (by quartile) variables. Global cognition was assessed using the Mini-Mental State Examination four times between 2008 and 2017, with a score below 24 being considered as MCI. Cox proportional hazards models were used to examine the associations.

Results: During a 9-year follow-up, 486 (15.7%) participants developed MCI. After adjustment for all covariates, higher UA had a dose-response association with a lower risk of MCI (all P_{for  trend} < 0.05). Participants in the highest UA quartile group had a reduced risk [hazard ratio (HR), 0.73; 95% (CI): 0.55–0.96] of MCI, compared with those in the lowest quartile group. The associations were still robust even when considering death as a competing risk. Subgroup analyses revealed that these associations were statistically significant in younger older adults (65–79 years) and those without hyperuricemia. Similar significant associations were observed when treating UA as a continuous variable.

Conclusions: High blood UA level is associated with reduced risks of MCI among Chinese older adults, highlighting the potential of managing UA in daily life for maintaining late-life cognition.

Mortality of People with Parkinson's Disease in a Large UK-Based Cohort Study: Time Trends and Relationship to Disease Duration

Background

Parkinson’s disease (PD) is associated with increased mortality, but little is known about changes over time, and relationship to disease progression.

Objectives

To explore how PD mortality rates have changed over time and their relationship to disease duration and demographics using a large population-based cohort in the UK.

Methods

We included individuals aged 50+ years with a first recording of PD diagnosis and at least two prescriptions of any antiparkinsonian drug actively registered within a general practice from 2006 to 2016 and up to six frequency-matched controls from The Health Improvement Network (THIN) database. We estimated adjusted mortality rates using multivariable Poisson regression.

Results

A total of 10,104 people with a diagnosis of PD and 55,664 people without PD were included. Overall, PD was associated with slightly increased mortality compared to non-PD controls (adjusted mortality rate ratio: 1.14; 95% CI: 1.03 to 1.19). Adjusted mortality rates per 1000 person-years at risk for people with PD approximately doubled in the 5 years following diagnosis from 43 (95% CI: 38 to 48) to 75 (95% CI: 64 to 85). Following adjustments for age, gender, and time since diagnosis, mortality rates between 2007 and 2016 declined more slowly for people with PD (2% per year; 95% CI: 0%–4%) compared to people without PD (5% per year; 95% CI: 3%–6%).

Conclusions

Whilst mortality in PD is only slightly increased overall, it gradually increases with advancing disease. There has been a decline in mortality in PD over time, but this decrease was less pronounced than that in the general population.

Association between higher serum uric acid levels within the normal physiological range and changes of lumbar spine bone mineral density in healthy Chinese postmenopausal women: a longitudinal follow-up study

OBJECTIVES

The aim of this study was to investigate whether higher serum uric acid (SUA) levels within the physiological range were associated with changes in lumbar spine bone mineral density (LBMD) in postmenopausal women without existing lumbar spine osteoporosis after a longitudinal follow-up of 3.09 years, and to further confirm the relationship between SUA and bone mineral density (BMD) in other sites such as femoral neck, total hip, and trochanter at follow-up.

METHODS

A longitudinal study of 175 healthy postmenopausal women without osteoporosis was conducted in Shenyang, China. BMD of the lumbar spine, femoral neck, total hip, and trochanter were measured using dual-energy x-ray absorptiometry at each visit. Pearson's correlation analysis and regression analyses were performed to determine any associations.

RESULTS

There were positive correlations between baseline SUA and BMD of the lumbar spine (P = 0.03), total hip (P = 0.04), and trochanter (P = 0.04). Moreover, higher baseline SUA levels were independently associated with LBMD decline and the odds ratio of the baseline SUA of the third quartile group was 0.12 (95% confidence interval, 0.02-0.70, P < 0.05), with P = 0.23 for the trend in baseline SUA when compared with participants in the lowest, first quartile group after adjustment for many potential confounding variables.

CONCLUSIONS

Higher SUA levels within the normal physiological range were independently associated with decreased LBMD, and SUA levels were positively related to the BMD of the lumbar spine, total hip, and trochanter in healthy Chinese postmenopausal women.

Risk of dementia in gout and hyperuricaemia: a meta-analysis of cohort studies

OBJECTIVES

Gout, characterised by hyperuricaemia with monosodium urate crystal formation and inflammation, is the most common inflammatory arthritis in adults. Recent studies have found that elevated uric acid levels are related to the occurrence of dementia. We conducted a study to investigate the association between dementia and gout or hyperuricaemia.

DESIGN

Systematic review and meta-analysis of cohort studies.

DATA SOURCES

Studies were screened from inception to 28 June 2019 by searching Medline, Embase and the Cochrane Library databases.

ELIGIBILITY CRITERIA

Cohort studies comparing the risk of dementia in patients with gout and hyperuricaemia versus non-gout and non-hyperuricaemia controls were enrolled.

DATA EXTRACTION AND ANALYSIS

Two reviewers separately selected studies and extracted data using the Medical Subject Headings without restriction on languages or countries. The adjusted HRs were pooled using the DerSimonian and Laird random effects model. Sensitivity analyses were conducted to evaluate the stability of the results. Publication bias was evaluated using Egger's and Begg's tests. Quality assessment was performed according to the Newcastle-Ottawa Scale.

RESULTS

Four cohort studies that met the inclusion criteria were included in our meta-analysis. We found that gout and hyperuricaemia did not increase the risk of dementia, with a pooled HR of 0.94 (95% CI 0.69 to 1.28), but might decrease the risk of Alzheimer's disease (AD), with a pooled HR of 0.78 (95% CI 0.64 to 0.95). There was little evidence of publication bias. Quality assessment of the included studies was high (range: 6-8 points).

CONCLUSIONS

Our study shows that gout and hyperuricaemia do not increase the risk of dementia. However, gout and hyperuricaemia might have a protective effect against AD. Due to the limited number of research articles, more investigations are needed to demonstrate the potential relationship between dementia and gout or hyperuricaemia.

Effects of baseline serum uric acid and apolipoprotein E4 on longitudinal cognition and cerebral metabolism

Serum uric acid, a natural antioxidant, may have a protective effect on the progression of Alzheimer's disease (AD). To investigate the effect of serum uric acid on longitudinal cognitive and brain metabolic changes, we utilized data on baseline serum uric acid levels, APOE genotyping, and longitudinal cognitive scores from the Alzheimer's Disease Neuroimaging Initiative for 1,343 participants with normal cognition (NC), mild cognitive impairment (MCI), or dementia. In 979 participants, brain metabolism was measured using ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) images. Higher serum uric acid levels exhibited a detrimental effect on NC, whereas a protective trend was observed in individuals with cognitive impairment. Interestingly, higher uric acid levels were associated with a slower decline in cognitive scores and brain metabolism in females with MCI, and this effect was found in APOE4 carriers, but not in non-carriers. Longitudinal AD-like patterns of brain metabolism on FDG-PET images also appeared to mediate the effects of baseline uric acid levels on longitudinal cognitive decline. In summary, higher serum uric acid may interact with APOE4 to alleviate longitudinal metabolic changes and cognitive decline in female MCI patients.

Serum Uric Acid May Aggravate Alzheimer's Disease Risk by Affecting Amyloidosis in Cognitively Intact Older Adults: The CABLE Study

BACKGROUND

Serum uric acid (SUA) affects the reaction of oxidative stress and free radicals in the neurodegenerative processes. However, whether SUA impacts Alzheimer's disease (AD) pathology remains unclear.

OBJECTIVE

We aimed to explore whether high SUA levels can aggravate the neurobiological changes of AD in preclinical AD.

METHODS

We analyzed cognitively intact participants (n = 839, age 62.16 years) who received SUA and cerebrospinal fluid (CSF) biomarkers (amyloid-β [Aβ], total tau [t-Tau], and phosphorylated tau [p-Tau]) measurements from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) database using multivariable-adjusted linear models.

RESULTS

Levels of SUA in the preclinical AD elevated compared with the healthy controls (p = 0.007) and subjects with amyloid pathology had higher concentration of SUA than controls (p = 0.017). Roughly, equivalent levels of SUA displayed among cognitively intact individuals with or without tau pathology and neurodegeneration. CSF Aβ1 - 42 (p = 0.019) and Aβ1 - 42/Aβ1 - 40 (p = 0.027) were decreased and CSF p-Tau/Aβ1 - 42 (p = 0.009) and t-Tau/Aβ1 - 42 (p = 0.043) were increased with the highest (> 75th percentile) SUA when compared to lowest SUA, implying a high burden of cerebral amyloidosis in individuals with high SUA. Sensitivity analyses using the usual threshold to define hyperuricemia and precluding drug effects yielded robust associations. Nevertheless, the quadratic model did not show any U-shaped relationships between them.

CONCLUSION

SUA may aggravate brain amyloid deposition in preclinical AD, which corroborated the detrimental role of SUA.

Association between Anti-inflammatory Drug and Dementia in Patients with Gout: A Nationwide, Population-Based Nested Case-Control Study

Introduction: The interaction between hyperuricemia and the cognitive system is still under debate, with studies presenting somewhat conflicting results. Objectives: This study aimed to investigate the risk of dementia in patients with gout who are administered anti-inflammatory drug treatment. Methods: Gouty arthritis patients aged 50 years and older, who received at least one of the background therapy drugs (colchicine, corticosteroids, or nonsteroidal anti-inflammatory drugs for 6 months), were divided into the following groups and compared: patients who had dementia over a period of 5 years (n = 2,292) and matched patients without dementia (n = 2,292). Results: We found that the most significant risk factors for dementia were stroke (OR, 2.66; 95% C.I., 2.33-3.03; AOR, 2.39; 95% C.I., 2.08-2.75) and depression (OR, 3.72; 95% C.I., 3.01-4.6; AOR, 3.25; 95% C.I., 2.60-4.05). The results of anti-gout drug administration, which impacted the dementia risk among patients of all ages (but especially in 50-64-year-old patients), demonstrated a higher risk ratio after 90 days of corticosteroid use (OR, 3.39; 95% C.I., 1.15-9.99), which was further increased after 180 days (OR, 3.61; 95% C.I., 1.31-9.94). We revealed that female patients experienced a significant increase in dementia risk after 90 days of corticosteroid administration, whereas male patients experienced a significant increase only after 180 days (OR, 1.52; 95% C.I., 1.06-2.17). Conclusion: We had identified that > 90-day corticosteroid administration is a significant dementia risk factor in both female and male patients of all ages, especially in the 50-60-year-old group.

Serum Uric Acid and the Risk of Dementia: A Systematic Review and Meta-Analysis

Background: This meta-analysis aimed to evaluate the relationship between serum uric acid (UA) and the risk of dementia and its subtypes.

Methods: Embase, PubMed, and Web of Science were searched from inception to July 2020. Random-effect models were employed to analyze the standard mean difference (SMD) with the corresponding 95% confidence intervals (CI).

Results: Twenty-three eligible studies involving 5,575 participants were identified. The overall results showed lower levels of UA in dementia relative to non-dementia controls [SMD = −0.32 (−0.64; −0.01) p = 0.04]. The subgroup analysis of the type of dementia demonstrated a significant association of UA with Alzheimer's disease (AD) [SMD = −0.58 (−1.02; −0.15) p = 0.009] and Parkinson's disease with dementia (PDD) [SMD = −0.33 (−0.52; −0.14) p = 0.001] but not with vascular dementia (VaD). The stratification analysis of the concentrations of UA revealed that the UA quartile 1–2 was negatively correlated with dementia and neurodegenerative subtypes (p < 0.05), whereas a positive correlation of UA quartile 4 with dementia was noted (p = 0.028). Additionally, the meta-regression analysis on confounders showed that not age, body mass index, diabetes mellitus, hypertension, or smoking but education (p = 0.003) exerted an influence of the UA in the risk estimate of dementia.

Conclusions: Low concentrations of UA (< 292 μmol/L or 4.91 mg/dL) is a potential risk factor for AD and PDD but not for VaD. The mechanism of different concentrations of the UA in dementia needs to be confirmed through further investigation.

Quality of Life in Elders with Suspected Alzheimer Disease: An Urban Health Centers-Based Study from Iran

Background/Aims

Quality of life (QOL) and Alzheimer disease (AD) among older people have been recognized as public health challenges. Here, we investigated the association between QOL and AD in the elders.

Methods

In this cross-sectional study, elderly people were selected from urban health centers (Shiraz, Iran) by multistage cluster random sampling and were interviewed using LEIPAD (for QOL) and Montreal Cognitive Assessment (for AD) questionnaires. The data was analyzed using Mplus (version 6.12) and IBM SPSS (version 25) software.

Results

The participants consisted of 182 elderly with a mean age of 67 ± 5.05 years, and 95 (52.2%) of them were females. There were 161 (88.5%) and 130 (71.4%) cases educated up to 12 years and married, respectively. Furthermore, 46 (25.3%) had low-to-moderate QOL, and 132 (72.5%) were suspected to have AD. QOL was inversely associated with AD, and men (β = -0.310) were more affected than women (β = -0.290). AD (β = -0.298), age (β = -0.288), hypertension (β = -0.267), education (β = 0.260), and body mass index (β = -0.198) were determinants of QOL. Also, physical activity was indirectly associated with QOL (β = 0.076). AD was correlated with the cognitive functioning component of QOL (r = -0.72).

Conclusion

One elder out of 4, did not have desirable QOL and 3 elders out of 4 were suspected to have AD. AD can decrease QOL among the older people. Screening of the elders for AD is recommended to improve their QOL by health centers.

Association Between Use of Anti-gout Preparations and Dementia: Nested Case-Control Nationwide Population-Based Cohort Study

Objectives: Gout is the most common form of inflammatory arthritis and was found to be independently associated with incident dementia in the elderly. However, the associations between anti-gout preparations and dementia were not well-studied.

Methods: Data were collected from Taiwan's National Health Insurance Research Database (NHIRD). A 2005–2013 retrospective cohort study was conducted, and all investigated subjects were identified by International Statistical Classification of Diseases and Related Health Problems, 9th Revision, Clinical Modification. Conditional logistic regression was used to evaluate the odds ratio of dementia in relation to different gout preparations (benzbromarone, allopurinol, sulfinpyrazone, probenecid) and number of days of anti-gout preparation use, after adjustment for potential confounding variables.

Results: A total of 3,242 gout patients with and without dementia were selected from the NHIRD and included in the final analysis after 1:1 matching for age, gender, and diagnosis year of gout. In the anti-gout preparations, only use of Benzbromarone decreased the risk of dementia (adjusted OR, 0.81; 95% CI, 0.68–0.97). The result of the subgroup analysis revealed a trend toward a lower risk of dementia with longer use of benzbromarone. Use of benzbromarone for ≥180 days showed a significantly lower risk of dementia (adjusted OR, 0.72; 95% CI, 0.58–0.89). Moreover, the protective effect was more pronounced in males compared with females.

Conclusion: This cohort study reveals that gout patients taking benzbromarone are at a decreased risk of developing incident dementia, especially with longer use and in male. Further prospective trials are warranted to confirm our findings.

Associations of BMI and Serum Urate with Developing Dementia: A Prospective Cohort Study

CONTEXT

Recent studies have suggested that a higher body mass index (BMI) and serum urate levels were associated with a lower risk of developing dementia. However, these reverse relationships remain controversial, and whether serum urate and BMI confound each other is not well established.

OBJECTIVES

To investigate the independent associations of BMI and urate, as well as their interaction with the risk of developing dementia.

DESIGN AND SETTINGS

We analyzed a cohort of 502 528 individuals derived from the UK Biobank that included people aged 37-73 years for whom BMI and urate were recorded between 2006 and 2010. Dementia was ascertained at follow-up using electronic health records.

RESULTS

During a median of 8.1 years of follow-up, a total of 2138 participants developed dementia. People who were underweight had an increased risk of dementia (hazard ratio [HR] = 1.91, 95% confidence interval [CI]: 1.24-2.97) compared with people of a healthy weight. However, the risk of dementia continued to fall as weight increased, as those who were overweight and obese were 19% (HR = 0.81, 95%: 0.73-0.90) and 22% (HR = 0.78, 95% CI: 0.68-0.88) were less likely to develop dementia than people of a healthy weight. People in the highest quintile of urate were also associated with a 25% (HR = 0.75, 95% CI: 0.64-0.87) reduction in the risk of developing dementia compared with those who were in the lowest quintile. There was a significant multiplicative interaction between BMI and urate in relation to dementia (P for interaction = 0.004), and obesity strengthens the protective effect of serum urate on the risk of dementia.

CONCLUSION

Both BMI and urate are independent predictors of dementia, and there are inverse monotonic and dose-response associations of BMI and urate with dementia.

Relationship of Serum Uric Acid to Hematoma Volume and Prognosis in Patients with Acute Supratentorial Intracerebral Hemorrhage

BACKGROUND

Oxidative stress and inflammation play important roles in the neuronal injury caused by intracerebral hemorrhage (ICH). Uric acid (UA), an important natural antioxidant, might reduce the neuronal injury caused by ICH. Delineating the relationship between UA and ICH will enhance our understanding of antioxidative mechanisms in recovery from ICH.

METHODS

We conducted a retrospective study of 325 patients with acute supratentorial ICH to investigate the relationship between serum UA levels and hematoma volumes and prognosis. A hematoma volume of ≥30 mL was defined as a large hematoma. An unfavorable outcome was defined as a modified Rankin scale score of 4-6 on day 30.

RESULTS

The serum UA level was significantly lower in the patients with a large hematoma volume (median, 306 μmol/L; 25th to 75th percentile, 243-411 μmol/L) than in those with a small hematoma volume (median, 357 μmol/L; 25th to 75th percentile, 271-442 μmol/L; P = 0.012). Similarly, the unfavorable outcome group had had lower serum UA levels (median, 309 vs. 363 μmol/L; P = 0.009) compared with the favorable outcome group. The results of the multivariate logistic analysis indicated that a lower serum UA level was associated with a larger hematoma volume (odds ratio, 0.996; P = 0.006) and an unfavorable outcome (odds ratio, 0.997; P = 0.030).

CONCLUSIONS

The results from the present study have indicated that in patients with acute supratentorial ICH, a low serum UA level might indicate that the patient has a large hematoma volume and might be a risk factor for a poor day 30 functional prognosis.

Hypouricemia and Mortality Risk in the US General Population

OBJECTIVE

The most recent European Alliance of Associations for Rheumatology (EULAR) recommendations for gout advise against maintaining a serum urate (SU) level of <3 mg/dl for prolonged periods of time. While several Asian cohort studies have shown higher rates of mortality in individuals with extremely low SU levels, data from non-Asian cohort studies are scarce, and the relationship between hypouricemia, cardiovascular risk, and mortality remains unclear.

METHODS

Using data collected from the 1988-1994 and 1999-2008 National Health and Nutrition Examination Survey (NHANES), we examined the relationship between SU level and overall and cause-specific mortality in 41,807 adults in the US. We calculated multivariable hazard ratios (HRs) that were compared to a referent SU level of 5-6 mg/dl for SU categories <4, 4-5, 6-7, 7-8, and >8 mg/dl in men and SU categories <3, 3-4, 4-5, 6-7, and >7 mg/dl in women.

RESULTS

A higher mortality risk was not observed in women who had an SU level of <3 mg/dl (HR 1.09 [95% confidence interval (95% CI) 0.92-1.28]). A 28% higher mortality risk was observed in men who had an SU level of <4 mg/dl (HR 1.28 [95% CI 1.13-1.45]), with a nearly three-times higher mortality risk from diabetes mellitus also noted (HR 2.89 [95% CI 1.59-5.23]), but no increase in mortality from any other specific cause.

CONCLUSION

We found no long-term excess mortality risk among American women with SU levels as low as <3 mg/dl, a finding which is incompatible with the notion of a causal relationship between hypouricemia and premature mortality in women. We found excess all-cause mortality and diabetes mellitus-related mortality among hypouricemic American men, which may in part be attributable to the uricosuric effect of hyperglycemia in fatal uncontrolled diabetes mellitus (analogous to reverse causality).

Redox signaling and Alzheimer's disease: from pathomechanism insights to biomarker discovery and therapy strategy

Abstract

Aging and average life expectancy have been increasing at a rapid rate, while there is an exponential risk to suffer from brain-related frailties and neurodegenerative diseases as the population ages. Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide with a projected expectation to blossom into the major challenge in elders and the cases are forecasted to increase about 3-fold in the next 40 years. Considering the etiological factors of AD are too complex to be completely understood, there is almost no effective cure to date, suggesting deeper pathomechanism insights are urgently needed. Metabolites are able to reflect the dynamic processes that are in progress or have happened, and metabolomic may therefore provide a more cost-effective and productive route to disease intervention, especially in the arena for pathomechanism exploration and new biomarker identification. In this review, we primarily focused on how redox signaling was involved in AD-related pathologies and the association between redox signaling and altered metabolic pathways. Moreover, we also expatiated the main redox signaling-associated mechanisms and their cross-talk that may be amenable to mechanism-based therapies. Five natural products with promising efficacy on AD inhibition and the benefit of AD intervention on its complications were highlighted as well.

Graphical Abstract

Ankylosing spondylitis is associated with an increased risk of dementia: A systematic review and meta-analysis

OBJECTIVES

To investigate the relationship between ankylosing spondylitis (AS) and risk of dementia.

METHODS

Potentially eligible studies that compared the risk of developing dementia between patients with AS and individuals without AS were identified from MEDLINE and EMBASE databases from inception to May 2019 using a search strategy that comprised terms for "dementia" and "ankylosing spondylitis". Eligible studies could be either cohort studies or case-control studies. For cohort design, eligible studies included patients with AS and comparators without AS and followed them for incident dementia. For case-control design, eligible studies included cases with dementia and controls without dementia and explored prior history of AS in both groups. Effect estimate and standard error from each study were extracted and combined together using the random effect, generic inverse variance. Funnel plot was used to assess for publication bias.

RESULTS

A total of 7091 articles were identified using the aforementioned search strategy. After 2 rounds of independent review by 3 investigators, 4 studies fulfilled the inclusion criteria and were included into the meta-analysis. The risk of developing dementia was significantly higher among patients with AS than individuals without AS with the pooled relative risk of 1.19 (95% CI 1.01-1.41; I²  = 76%). The funnel plot was relatively symmetric and was not suggestive of presence of publication bias.

CONCLUSION

A significantly 1.2 fold higher risk of developing dementia among patients with AS was demonstrated by this systematic review and meta-analysis.

Gout and the risk of epilepsy: A population-based cohort study

Gout is a chronic disease related to uric acid metabolism. It involves crystals of uric acid accumulating in the joints, causing joint pain and releasing cytokines that trigger inflammation. Inflammation is a key component in the pathogenesis of epilepsy. Thus, we conducted a cohort study to investigate if epilepsy is associated with gout and determine the risk of epilepsy in patients with gout.The gout cohort was obtained from the Registry of Catastrophic Illnesses Patient Database (RCIPD). We identified 104,238 patients who were aged 20 years or more and newly diagnosed with gout between 2000 and 2011 and 3 outpatient visits or history of gout-specific hospitalization between 2000 and 2011. Patients without gout were frequency matched with the gout cohort at a 2:1 ratio according to age, sex, comorbidities, and year of gout diagnosis.The gout cohort showed a 1.27-fold higher overall crude hazard ratio (HR) for epilepsy compared with the control cohort. After we adjusted the analyses by age, sex, and comorbidities the gout patients displayed an increased risk of epilepsy compared with the control group (adjusted HR = 1.25, 95% confidence interval = 1.15-1.36).This study revealed a significantly higher risk of epilepsy in patients with gout. It provides further evidence for the debate around the effect of gout on brain health.