A methodological study of exposome based on an open database: Association analysis between exposure to metal mixtures and hyperuricemia.

BACKGROUND: Exposome recognizes that humans are constantly exposed to multiple environmental factors, and elucidating the health effects of complex exposure mixtures places greater demands on analytical methods. OBJECTS: We aimed to explore the association between mixed exposure to metals and hyperuricemia (HUA), and highlight the potential of explainable machine learning (EML) and causal mediation analysis (CMA) for application in the analysis of exposome data. METHODS: Pre-pandemic data from the National Health and Nutrition Examination Survey (NHANES) 2011-2020 and a total of 13780 individuals were included. We first used traditional statistical models (multiple logistic regression (MLR) and restricted cubic spline regression (RCS)) and EML to explore associations between mixed metals exposures and HUA, followed by the CMA using the 4-way decomposition method to analyze the interaction and mediation effects among BMI or estimated glomerular filtration rate (eGFR), metals and HUA. RESULTS: The prevalence of HUA was 18.91% (2606/13780). The MLR showed that mercury (Q4 vs Q1: OR = 1.08, 95% CI:1.02-1.14) and lead (Q4 vs Q1: OR = 1.23, 95% CI:1.13-1.34) were generally positively associated with HUA. Higher concentrations of lead, mercury, selenium and manganese were associated with the increased odds of HUA, and BMI and eGFR were the top two variables attributable to the risk of developing HUA in the EML. Subgroup analyses from the MLR and EML consistently demonstrated the positive relationship between exposure to lead, mercury and selenium in participants with BMI <25 kg/m2 and BMI ≥30 kg/m2. BMI mediated 32.12% of the association between lead exposure and HUA, and the interaction between BMI and lead accounted for 3.88% of the association in the CMA. CONCLUSIONS: Heavy metals can increase the HUA risk and BMI or eGFR can mediate and interact with metals to cause HUA. Future studies based on exposome can attempt to utilize the EML and CMA.

Association between dietary approaches to stop hypertension (DASH) diet and hyperuricemia among Chinese adults: findings from a nationwide representative study.

BACKGROUND: Certain foods and food groups could positively or negatively impact serum uric acid (SUA) levels. However, evidence on the holistic dietary strategy to prevent and control hyperuricemia (HUA) development remains limited. OBJECTIVE: The aim of this research work was to explore the association of dietary approaches to stop hypertension (DASH) diet with SUA levels and odds of HUA among Chinese adults. METHODS: This research premise included 66,427 Chinese adults aged 18 and above who were part of the China Adult Chronic Disease and Nutrition Surveillance in 2015. Dietary consumptions were assessed via the household condiment weighing approach and a three-day, 24-hour dietary recall. Total fat, saturated fat, calcium, protein, potassium, cholesterol, magnesium, fiber, and sodium were all adopted to calculate the DASH score (score range, 0-9). The associations of DASH score with SUA levels and odds of HUA were evaluated using multiple linear and logistic regression models, respectively. RESULTS: We established that a higher DASH score was linked with a lower SUA levels (ß = - 0.11; 95% CI: - 0.12, - 0.1; p < 0.001) and odds of HUA (OR = 0.85; 95% CI: 0.83, 0.87; p < 0.001) after adjustment for age, sex, ethnicity, education status, marital status, health behaviours and health factors. The association of the DASH diet with odds of HUA was stronger among men (p-interaction = 0.009), non-Han Chinese (p-interaction< 0.001) as well as rural residents (p-interaction< 0.001). CONCLUSIONS: Our results illustrate that the DASH diet was remarkably negatively with SUA levels and odds of HUA in the Chinese adult population.

Hyperuricemia: an unrecognized risk factor for kidney-related sequelae in children with hemolytic uremic syndrome.

BACKGROUND: Chronic kidney-related sequelae after STEC-HUS occur in 20-40% of patients. Hyperuricemia (HU) may cause acute and chronic toxicity involving the kidneys. We retrospectively assessed if there was an association between the presence of HU during the acute illness and that of kidney-related sequelae in children with STEC-HUS. METHODS: Children with STEC-HUS who had clinical and laboratory data at 2 years of follow-up were included in this case-control study. Univariate and multivariate analyses were performed between patients with (cases) or without (controls) kidney-related sequelae to identify factors associated with outcomes, including different measures of serum uric acid (sUA) (baseline level, peak, and duration of HU). HU was defined as sUA > 8 mg/dL. RESULTS: Of 86 patients included, 77.9% had HU. Patients with sequelae (n = 41) had a higher prevalence of HU (41/41 vs. 26/45, p < 0.01), higher baseline leukocyte count, serum creatinine (sCr), and sUA levels as well as lower sodium than controls. During hospitalization, cases also had higher sCr peak, sUA peak and duration of HU, requirement and duration of dialysis, extrarenal complications, and hypertension. By multivariate analysis, after adjusting for length of dialysis, only duration of HU (p = 0.0005; OR 1.7, 95% CI 1.27-2.36) remained as an independent predictor of sequelae, with a best cutoff of 5.5 days (AUC 0.95, specificity 80%, sensitivity 100%). CONCLUSIONS: The presence of HU is a common finding in children with STEC-HUS and its duration during the acute stage was associated with kidney-related sequelae, regardless of the duration of dialysis. A higher resolution version of the Graphical abstract is available as Supplementary Information.

Impact of Coffee/Green Tea/Soft Drink Consumption on the Risk of Hyperuricemia: A Cross-Sectional Study.

This cross-sectional study aimed to investigate the association between hyperuricemia and the frequency of coffee, tea, and soft drink consumption, based on data from the Korean Genome and Epidemiology Study (KoGES) (2004-2016). We used the KoGES health examinee data, obtained from urban residents aged ≥ 40 years. Information on the participants' medical history, nutrition (total calorie, protein, fat, and carbohydrate intake), frequency of alcohol consumption, smoking status, household income, and frequency of coffee/green tea/soft drink intake was collected. A logistic regression model was used to analyze the data. Subgroup analyses were performed according to the participant's age and sex. Among 173,209 participants, there were 11,750 and 156,002 individuals with hyperuricemia and non-hyperuricemia controls, respectively. In an adjusted model, frequent coffee and green tea consumption did not increase the risk of hyperuricemia, compared to the "no intake" reference group. However, an adjusted odds ratio of hyperuricemia was 1.23 (95% confidence interval, 1.11-1.35, p < 0.001) for participants who reported consuming soft drinks ≥ 3 times per day, compared to the respective "no drink" reference group. Even after adjusting for nutritional and sociodemographic factors, frequent soft drink intake was associated with an increased risk of hyperuricemia. Meanwhile, neither coffee nor green tea intake was associated with an increased risk of hyperuricemia.

[Gout]. / La maladie goutteuse.

Gout is a chronic disease due to the deposition of monosodium urate microcrystals in joints and tissues. Its incidence and prevalence are increasing worldwide in close relation with the epidemic of obesity and metabolic syndrome. Gout is related to chronic hyperuricemia that should be treated to ensure the reduction or even the disappearance of acute attacks ("gout flares") and to reduce the size and number of tophi. If arthritis of the first metatarsophalangeal joint is the most typical form, other joints may be affected, including the spine. Demonstration of urate microcrystals arthritis allows diagnosis of gout but, in the absence of possibility of performing joint puncture, imaging may be useful for providing complementary diagnostic elements. Appropriate care is essential to reduce the number of flares and the evolution towards gouty arthropathy but also in terms of public health in order to reduce costs related to this pathology.

The Associations Between Gonadal Hormones and Serum Uric Acid Levels in Men and Postmenopausal Women With Diabetes.

Introduction: In assessing the development of hyperuricemia in diabetic adults, the role of the sex steroid axis is underappreciated. Furthermore, dehydroepiandrosterone (DHEA) has been recommended as a nutritional supplement. However, is DHEA suitable for diabetic adults with hyperuricemia? This issue has received little attention. Aim: The objective of this study was to investigate the associations between gonadal hormones and uric acid (UA) levels in diabetic adults, paying particular attention to the association between DHEA and UA levels. Methods: We analyzed 4,426 participants out of 4,813 diabetic adults enrolled from seven communities in a cross-sectional survey conducted in 2018. Participants underwent several examinations, including assessments of anthropometric parameters, blood pressure, glucose, lipid profiles, UA, total testosterone (TT), estradiol (E2), the follicle-stimulating hormone (FSH), the luteinizing hormone (LH), and dehydroepiandrosterone (DHEA). Results: Among men and compared with individuals in the first quartile, participants in the fourth quartile of TT and FSH had odds of hyperuricemia that were significantly decreased by so much as 48 and 34%, respectively (both P < 0.05). However, participants in the fourth quartile of DHEA had 79% increased odds of hyperuricemia (P < 0.05). Among postmenopausal women, participants in the fourth quartile of DHEA, TT, and LH had odds of hyperuricemia that were significantly increased by 155, 99, and 76%, respectively (all P < 0.05). These associations were adjusted for potential confounding factors. Conclusions: Sex differences were found in the associations between gonadal hormones and UA levels in diabetic men and postmenopausal women, which should be monitored to prevent hyperuricemia when sex hormone treatment, especially DHEA, is administered. Further studies are needed.

Association between dyslipidemia and serum uric acid levels in Korean adults: Korea National Health and Nutrition Examination Survey 2016-2017.

OBJECTIVES: Despite the growing pieces of evidence linking hyperuricemia with metabolic syndrome and cardiovascular disease, the relationship between dyslipidemia and serum uric acid has not yet been established. This study aimed to investigate the association between individual components of dyslipidemia and serum uric acid by using the nationally representative Korea National Health and Nutrition Examination Survey 2016-2017. METHODS: A total of 8,722 participants (age ≥ 19 years) without missing values were analyzed for this study. Serum uric acid levels according to the presence of individual dyslipidemia components were calculated using multivariable-adjusted general linear models (GLM). Odds ratios of individual dyslipidemia components to hyperuricemia were calculated using unadjusted and multivariable-adjusted logistic regression analysis. RESULTS: A total of 1,061 participants were identified as having hyperuricemia, with a prevalence of 12.2%. Multivariable-adjusted GLM demonstrated a significant trend between individual dyslipidemia components and serum uric acid levels (P < 0.05). A positive association between the numbers of dyslipidemia components and the increments of serum uric acid levels was also observed (P < 0.001). In multivariable-adjusted logistic regression analysis, odds ratios (OR) and 95% confidence interval (CI) of all dyslipidemia components to hyperuricemia were shown to be statistically significant (P < 0.05). When further adjusted for the combined components themselves, each 10 mg/dL increments of total cholesterol (OR 1.053; 95% CI 1.028-1.079), triglycerides (OR 1.017; 95% CI 1.009-1.026) and HDL-C (OR 0.804; 95% CI 0.729-0.887), retained significant correlation with hyperuricemia. CONCLUSION: Our study demonstrated that the dyslipidemia components of serum total cholesterol, triglycerides and LDL-C levels are positively associated with serum uric acid levels, whereas serum HDL-C levels are inversely related. Further complementary studies regarding other lipid parameters are needed to confirm the accurate association between dyslipidemia and serum uric acid levels.

Association between vitamin C intake and risk of hyperuricemia in US adults.

BACKGROUND AND OBJECTIVES: The relationship between vitamin C intake and hyperuricemia among the general US adult population has seldom been reported; thus, the present study examined the associations of total vitamin C (dietary vitamin C plus supplementary vitamin C) and dietary vitamin C intake with the risk of hyperuricemia. METHODS AND STUDY DESIGN: Pooled data from three 2-year cycles (2007-2012) of the cross-sectional National Health and Nutrition Examination Survey were used in the present study. Dietary intake data were extracted from two 24-hour dietary recall interviews. Logistic regression models were used to determine the associations between vitamin C intake and hyperuricemia risk. RESULTS: A total of 14885 adults aged 20 years or older (7269 men and 7616 women) were registered in the present study. The prevalence of hyperuricemia was 19.1%. Based on the lowest quartile of dietary vitamin C intake, multivariate adjusted odds ratios with 95% confidence intervals of hyperuricemia for quartiles 2-4 were 0.84 (0.74-0.95), 0.83 (0.73-0.94), and 0.72 (0.63-0.82), and those for total vitamin C intake were 0.87 (0.77-0.99), 0.85 (0.75-0.96), and 0.66 (0.58-0.76). Inverse associations between vitamin C intake and hyperuricemia were discovered in both men and women, even with or without covariate adjustments. CONCLUSIONS: Total vitamin C and dietary vitamin C intake are inversely associated with hyperuricemia in the general US adult population.

Dietary factors and risk of gout and hyperuricemia: a meta-analysis and systematic review.

BACKGROUND AND OBJECTIVES: To evaluate the associations of dietary factors and the risk of gout and hyperuricemia. METHODS AND STUDY DESIGN: PubMed and Embase databases were searched from inception to June 2017 for eligible studies. Nineteen prospective cohort or cross-sectional studies with adequate sample sizes are included, all involving red meat, seafoods, alcohol, fructose, dairy products, soy foods, high-purine vegetables and coffee. RESULTS: Meta-analysis revealed several dietary associations with gout risk: red meat: OR 1.29 (95% CI 1.16-1.44); seafoods: OR 1.31 (95% CI 1.01-1.68); alcohol: OR 2.58 (95% CI 1.81-3.66); fructose: OR 2.14 (95% CI 1.65- 2.78); dairy products: OR 0.56 (95% CI 0.44-0.70); soy foods: OR 0.85 (95% CI 0.76-0.96); high-purine vegetables: OR 0.86 (95% CI 0.75-0.98); coffee: OR 0.47 (95% CI 0.37-0.59).Dietary association with hyperuricemia risk (red meat: OR 1.24 (95% CI 1.04-1.48); seafoods: OR 1.47 (95% CI 1.16-1.86); alcohol: OR 2.06 (95% CI 1.60-2.67); fructose: OR 1.85 (95% CI 1.66-2.07); dairy products: OR 0.50 (95% CI 0.37-0.66); soy foods: OR 0.70 (95% CI 0.56-0.88); high-purine vegetables ingestion: OR 1.10 (95% CI 0.88-1.39), P=0.39; coffee:OR0.76 in men (95% CI 0.55-1.06), OR 1.58 in women (95% CI 1.16-2.16). CONCLUSION: The risk of hyperuricemia and gout is positively correlated with the intake of red meat, seafoods, alcohol or fructose, and negatively with dairy products or soy foods. High-purine vegetables showed no association with hyperuricemia, but negative association with gout. Coffee intake is negatively associated with gout risk, whereas it may be associated with increased hyperuricemia risk in women but decreased risk in men.

Hyperuricemia and Acute Renal Failure in Renal Transplant Recipients Treated With High-Dose Mizoribine.

BACKGROUND: Hyperuricemia is a common adverse event frequently found in renal transplant recipients with mizoribine (MZ). Hyperuricemia itself will be a cause of renal dysfunction, and renal dysfunction also will be a cause of hyperuricemia simultaneously. This study investigates frequency of hyperuricemia and renal failure in renal transplant recipients treated with high-dose MZ. PATIENTS AND METHODS: From December 2007 to October 2015, there was a total of 32 living related renal transplant recipients treated with high-dose MZ. Of the 32 patients, 28 were treated with urate-lowering medications. RESULTS: One patient received allopurinol (AP) and 13 patients received benzbromarone (BB). For 6 of them, their urate-lowering medications were converted to febuxostat (FX) form AP or BB. In the remaining 14 patients, FX was administered from the beginning. In 2 cases of ABO-incompatible living related renal transplant recipients who were maintained with high-dose MZ and BB, severe hyperuricemia and acute renal failure occurred. One patient was a 48-year-old man, and his creatinine (Cr) level increased to 8.14 mg/dL and his serum uric acid (UA) was 24.6 mg/dL. Another patient was a 57-year-old man, and his Cr level increased to 3.59 mg/dL and his UA was 13.2 mg/dL. In both cases Cr and UA were improved, and no finding of acute rejection and drug toxicity was observed in graft biopsy specimens. BB was switched to FX and discontinuance or reduction of MZ was done. CONCLUSION: Combination of MZ and BB has the risk of acute renal dysfunction after renal transplantation. Latent renal dysfunction should be watched for in renal transplant recipients receiving high-dose MZ.

Is coffee consumption associated with a lower risk of hyperuricaemia or gout? A systematic review and meta-analysis.

OBJECTIVES: To examine the associations of coffee consumption with the serum uric acid (SUA) level, hyperuricaemia (HU) and gout. DESIGN: Systematic review and meta-analysis. DATA SOURCES AND STUDY ELIGIBILITY CRITERIA: A comprehensive literature search up to April 2015, using PubMed and EMBASE databases, was conducted to identify the observational researches that examined the associations of coffee consumption with the SUA level, HU and gout. The standard mean difference (SMD), OR, relative risk (RR) and their corresponding 95% CIs for the highest and the lowest categories of coffee intake were determined. RESULTS: A total of 11 observational studies (6 cross-sectional, 3 cohort and 2 case-control studies) were included in this systematic review and meta-analysis. The combined SMD suggested that there was no significant difference between the highest and the lowest coffee intake categories in terms of the SUA level (SMD=-0.09, 95% CI -0.23 to 0.05; p=0.21). Meanwhile, the overall multivariable adjusted OR for HU showed no significant difference between the highest and the lowest coffee intake categories (OR=0.84, 95% CI 0.65 to 1.09; p=0.20). However, the overall multivariable adjusted RR for gout showed a significant inverse association between coffee consumption and the incidence of gout (RR=0.43, 95% CI 0.31 to 0.59, p<0.001). CONCLUSIONS: Current evidences are insufficient to validate the association between coffee consumption and a lower risk of HU. Owing to the limited number of studies, the available data show that coffee consumption may be associated with a lower risk of incident gout. Further well-designed prospective researches and randomised controlled trials are therefore needed to elaborate on these issues.

Association between low dietary zinc and hyperuricaemia in middle-aged and older males in China: a cross-sectional study.

OBJECTIVE: To examine the associations between dietary zinc intake and hyperuricaemia. DESIGN: Cross-sectional study. SETTING: This study was conducted in a health examination centre of China. PARTICIPANTS: A total of 5168 middle-aged and older participants (aged 40 years or above) (2697 men and 2471 women) were included. OUTCOME MEASURES: Dietary zinc intake was assessed using a validated semiquantitative food frequency questionnaire. Hyperuricaemia was defined as uric acid ≥416 µmol/L for males and ≥360 µmol/L for females. RESULTS: For males, the prevalence of hyperuricaemia was 22.9%. After adjusting for age, body mass index (BMI) and energy intake, the ORs were 0.68 (95% CI 0.45 to 0.92) in the second quintile, 0.63 (95% CI 0.45 to 0.89) in the third quintile, 0.68 (95% CI 0.46 to 1.00) in the fourth quintile and 0.55 (95% CI 0.35 to 0.87) in the fifth quintile comparing the lowest quintile of Zn intake, respectively (p for trend=0.03). In the multivariable adjusted model, the relative odds of hyperuricaemia were significantly decreased by 0.71 times in the second quintile of zinc intake (OR 0.71, 95% CI 0.52 to 0.98), 0.64 times in the third quintile (OR 0.65, 95% CI 0.44 to 0.94) and 0.55 times in the fifth quintile (OR 0.56, 95% CI 0.32 to 0.97) compared with those in the lowest quintile, and p for trend was 0.064. For females, the prevalence of hyperuricaemia was 10.0%, and unadjusted, minimally adjusted as well as multivariable adjusted ORs all suggested no significant association between dietary zinc intake and hyperuricaemia. CONCLUSIONS: The findings of this cross-sectional study indicated that dietary zinc intake was inversely associated with hyperuricaemia in middle-aged and older males, but not in females. The association was significant after considering the influence of age, BMI and energy intake, and after that, minimum adjustment remained independent of further confounding factors such as vitamin C intake, alcohol drinking status and nutrient supplementation.

The effect of coffee, tea, and caffeine consumption on serum uric acid and the risk of hyperuricemia in Korean Multi-Rural Communities Cohort.

Caffeine, a commonly consumed food constituent, is known to exert beneficial physiological effects in humans. There is a lack of comprehensive population data for the effects of caffeine intake on urate metabolism. Therefore, the aim of this study was to determine whether coffee, tea, and caffeine intake influences serum uric acid and the risk of hyperuricemia in the Korean Multi-Rural Communities Cohort. We enrolled 9,400 participants in this study. An assessment of various dietary intake amounts of substances such as coffee and tea was performed using a food frequency questionnaire. The content of caffeine was calculated from coffee (74 mg/cup) and tea (15 mg/cup) intake information from the past year. Multivariate logistic regression models, multiple linear regression models, and analysis of covariance were applied to identify any association of dietary intake with serum uric acid levels or the risk of hyperuricemia. No trends for coffee, tea, or caffeine intake were found according to each quintile with serum uric acid in males, although there were weak, marginally significant trends between the content of coffee and caffeine intake and serum uric acid level in females (p = 0.07 for both). Tea intake in males and caffeine intake in females were significantly different between non-hyperuricemia and hyperuricemia (p = 0.04 and p = 0.04, respectively). In addition, a significant association of serum uric acid level with tea intake in males (ß = 0.0006, p = 0.02) and with tea intake and caffeine intake in females (ß = 0.0003, p = 0.04 and ß = 0.0006, p = 0.02, respectively) was observed. There was no effect of coffee, tea, or caffeine intake on the risk of hyperuricemia in either males or females. This study suggests that caffeine consumption might have an effect on serum uric acid in females. However, coffee, tea, and caffeine intake amounts were not associated with the risk of hyperuricemia.

Hyperuricemia and the risk of ischemic stroke in patients with atrial fibrillation--could it refine clinical risk stratification in AF?

BACKGROUND: Although hyperuricemia has been reported to be a risk factor of stroke, the relationship between hyperuricemia and stroke in patients with atrial fibrillation (AF) remains uncertain. The goal of the present study was to investigate whether hyperuricemia could potentially refine clinical risk stratification in AF. METHODS: This study used the "National Health Insurance Research Database" in Taiwan. A total of 7601 AF patients who did not receive antiplatelet agents or oral anticoagulants were identified as the study population. Hyperuricemia was defined as having at least one episode of gout attack necessitating long-term treatment with uric acid-lowering agents. The association between hyperuricemia and ischemic stroke was analyzed. RESULTS: During the follow up of 3.0±2.7 years, 1116 patients (14.7%) experienced ischemic stroke with an annual rate of around 4.9%. Hyperuricemia significantly predicts stroke, with a hazard ratio (HR) of 1.280 after adjusting for CHA2DS2-VASc score and other comorbidities. Among the 376 patients with a CHA2DS2VASc score of 0, hyperuricemia can further stratify them into 2 groups with different stroke rates (7.1% versus 1.3%, p=0.020). The adjusted HR of hyperuricemia in predicting ischemic stroke diminished from 7.491 for patients with a CHA2DS2-VASc score of 0 to 1.659 for those with a score of 3, and became insignificant for patients with a score ≥4. CONCLUSIONS: Hyperuricemia was a significant risk factor of stroke which could potentially refine the clinical risk stratification in AF. It deserves a prospective trial to investigate whether it would change the current strategy for stroke preventions using oral anticoagulants.

Associations between concentrations of uric acid with concentrations of vitamin A and beta-carotene among adults in the United States.

Our objective was to examine the cross-sectional associations between concentrations of vitamin A and beta-carotene, a major source of vitamin A, with concentrations of uric acid in a nationally representative sample of adults from the United States. We conducted a cross-sectional study using data from up to 10893 participants aged ≥ 20 years of National Health and Nutrition Examination Survey from 2001 to 2006. Concentrations of uric acid adjusted for numerous covariates increased from 305.8 µmol/L in the lowest quintile of vitamin A to 335.3 µmol/L in the highest quintile (p for linear trend <0.001). The prevalence ratio for hyperuricemia also increased progressively across quintiles of serum vitamin A reaching 1.82 (95% confidence interval [CI]: 1.52, 2.16; p for linear trend <0.001) in the top quintile in the maximally adjusted model. Adjusted mean concentrations of uric acid decreased progressively from quintile 1 (333.8 µmol/L) through quintile 4 of concentrations of beta-carotene and were similar for quintiles 4 (313.5 µmol/L) and 5 (313.8 µmol/L). Concentrations of beta-carotene were inversely associated with hyperuricemia (adjusted prevalence ratio comparing highest with lowest quintile = 0.61; 95% CI: 0.52, 0.72; p for linear trend <0.001). Concentrations of uric acid were significantly and positively associated with concentrations of vitamin A and inversely with concentrations of beta-carotene. These cross-sectional findings require confirmation with experimental studies of vitamin A and beta-carotene supplementation.

The interplay between diet, urate transporters and the risk for gout and hyperuricemia: current and future directions.

Diet plays a significant role in the development of gout and hyperuricemia. Gout and hyperuricemia have likewise been associated with the development of cardiovascular disease and metabolic syndrome. Epidemiological studies have shown that certain foods influence levels of serum uric acid and the risk for development of gout.This article reviews the influence of dietary factors on serum uric acid levels and risk of gout, as well as the role of urate transporters in the development of hyperuricemia and gout.Various epidemiological studies have shown the effects of certain foods on the risk of developing gout and hyperuricemia. Low-fat dairy products, purine-rich vegetables, whole grains, nuts and legumes, and less sugary fruits, coffee and vitamin C supplements decrease the risk, whereas intake of red meat, fructose-containing beverages and alcohol increase the risk of gout. There is also an increased although basic understanding of the effects of vitamin C, alcohol and fructose on urate transporters. Certain foods can lead to a decreased or increased risk of development of gout and hyperuricemia. Advances have established the interplay of certain foods on urate transporters and renal handling of urate. More studies, especially prospective ones, are needed to increase our understanding of the roles of foods and urate transporters and other molecular mechanisms on the risk of developing gout and hyperuricemia.

Trends in hyperuricemia and gout prevalence: Nutrition and Health Survey in Taiwan from 1993-1996 to 2005-2008.

Hyperuricemia is a recognized risk factor for cardiovascular disease. This study investigated trends in uric acid levels, hyperuricemia and gout among adults in Taiwan from 1993-1996 to 2005-2008, using data collection from, Nutrition and health surveys in Taiwan (NAHSIT) conducted in 1993-1996 and 2005-2008. Information on food frequency, medical history, physical measures and fasting blood parameters were analyzed. Mean uric acid levels decreased between 1993-1996 and 2005-2008 in both genders (6.77 vs 6.59 mg/dL in men and 5.33 vs 4.97 mg/dL in women) and the prevalence of hyperuricemia declined from 25.3% to 22.0% in men (p<0.0001) and from 16.7% to 9.7% in women (p<0.0001). However, the prevalence of gout (self-reported) increased (4.74% vs 8.21% in men and 2.19% vs 2.33% in women, p<0.0001). Reduced rank regression was used to identify dietary patterns that explained significant amounts of variance in uric acid. Frequency of consumption of lean meat, soy products and soymilk, milk, eggs, vegetables, carrots, mushrooms, fruit and coffee were negatively associated with hyperuricemia, whereas consumption of organ meats, bamboo shoots, and soft drinks were positively associated with hyperuricemia. The dietary factor score (DFS) composed of the frequency of above food items decreased from -5.40 to -6.00 between the two surveys (p<0.0001). In conclusion, uric acid levels and prevalence of hyperuricemia both declined, whilst self-reported gout increased between 1993-1996 and 2005-2008. Changes in dietary patterns may in part explain the decrease in uric acid levels between the two national surveys.

Frequency, risk, and cost of gout-related episodes among the elderly: does serum uric acid level matter?

OBJECTIVE: We examined the association between serum uric acid (SUA) level and the frequency, risk, and cost of gout flares among the elderly. METHODS: Data were extracted from the Integrated Healthcare Information Services claims database (1999-2005). Patients were included if they had gout, were aged 65 years and older and had both medical and pharmacy benefits, and electronic laboratory data. Patients with gout and gouty episodes were identified using algorithms based on ICD-9-CM codes and medications. Logistic regression and negative binomial regressions were used to study the relationship between SUA concentration and the annual frequency and one-year risk of gout episodes. Generalized linear models were used to examine the direct healthcare costs associated with gout episodes in the 30 days following each episode. RESULTS: Elderly patients with gout (n = 2237) with high (6-8.99 mg/dl) and very high (> 9 mg/dl) SUA concentrations were more likely to develop a flare within 12 months compared to patients with normal (< 6 mg/dl) SUA levels (OR 2.1, 95% CI 1.7-2.6; OR 3.4, 95% CI 2.6-4.4, respectively). In multivariate regressions, the average annual number of flares increased by 11.9% (p < 0.001) with each unit-increase in SUA level above 6 mg/dl (p < 0.001). Among patients with very high SUA levels, average adjusted total healthcare and gout-related costs per episode were $2,555 and $356 higher, respectively, than those of patients with normal SUA levels (both p < 0.001). CONCLUSION: Higher SUA levels are associated with increased frequency and risk of gout episode, and with higher total and gout-related direct healthcare costs per episode.

Metabolic abnormalities are present in adults with elevated serum cystatin C.

Although metabolic anomalies are often seen in advanced chronic kidney disease (CKD), their presence in more mild states is unknown. We studied 6722 participants in the Third National Health and Nutrition Examination Survey, dividing them into three mutually exclusive groups consisting of those having a normal or mildly reduced estimated glomerular filtration rate (eGFR) (Modification of Diet in Renal Disease (MDRD) formula), those with normal or elevated serum cystatin C, and those with clinically relevant moderate or severely reduced eGFR (stage 3 or 4 of CKD). The prevalence of several metabolic abnormalities associated with moderate to advanced CKD was determined after standardization for age, race-ethnicity, and gender. In the absence of stage 3 or 4 CKD, patients with elevated serum cystatin C had a higher prevalence of low hemoglobin and elevated uric acid, homocysteine, phosphorus, fibrinogen, and C-reactive protein than patients with a normal serum cystatin C. Our results show that in adults with normal or mildly reduced eGFR, elevated serum cystatin C is associated with an increased prevalence of metabolic abnormalities traditionally found in moderate or severe CKD. Elevated serum cystatin C may identify patients with 'preclinical' kidney disease not detected by traditional serum creatinine measurements.