Coffee, tea, and caffeine consumption and serum uric acid level: the third national health and nutrition examination survey

Metabolite profiling reveals new insights into the regulation of serum urate in humans

Serum urate, the final breakdown product of purine metabolism, is causally involved in the pathogenesis of gout, and implicated in cardiovascular disease and type 2 diabetes. Serum urate levels highly differ between men and women; however the underlying biological processes in its regulation are still not completely understood and are assumed to result from a complex interplay between genetic, environmental and lifestyle factors. In order to describe the metabolic vicinity of serum urate, we analyzed 355 metabolites in 1,764 individuals of the population-based KORA F4 study and constructed a metabolite network around serum urate using Gaussian Graphical Modeling in a hypothesis-free approach. We subsequently investigated the effect of sex and urate lowering medication on all 38 metabolites assigned to the network. Within the resulting network three main clusters could be detected around urate, including the well-known pathway of purine metabolism, as well as several dipeptides, a group of essential amino acids, and a group of steroids. Of the 38 assigned metabolites, 25 showed strong differences between sexes. Association with uricostatic medication intake was not only confined to purine metabolism but seen for seven metabolites within the network. Our findings highlight pathways that are important in the regulation of serum urate and suggest that dipeptides, amino acids, and steroid hormones are playing a role in its regulation. The findings might have an impact on the development of specific targets in the treatment and prevention of hyperuricemia.

Gout: a critical analysis of scientific development

In recent years, scientific efforts on the topic "gout" have focused on pathogenetic aspects. This has opened new strategies of anti-inflammatory therapy and has improved urate-lowering therapy. So far, a scientometric analysis of the topic "gout" has not been generated despite an increased need for it in times of modified evaluation criteria for academic personnel and a subsequent tendency to co-authorship and author self-citation. The study aims to evaluate quality and quantity of scientific research dealing with the topic "gout" and to contribute to distinguish relevant research output. The current study uses scientometric methods and large-scale data analysis to evaluate quality and quantity of scientific efforts in the field of "gout." Data were gained from PubMed and ISI-Web. In the last 22 years (1990–2012), 4,424 items were published by 71 countries, of which the USA have been the most productive supplier with 32 % of all publications, followed in considerable distance by the United Kingdom, Japan, Spain and Germany, respectively. The USA have established their position as center of international cooperation. The most prolific journals in the field of gout were "Arthritis and Rheumatism," "Annals of the Rheumatic diseases" and the "Journal of Rheumatology." Our analysis specifies the most productive authors and institutions engaged with the topic, the most successful international and national cooperation and the most prolific journals and subject areas. Nevertheless, scientometric indicators, such as h-index, citation rate and impact factor, commonly used for assessment of scientific quality, should be seen critically due to distortion by bias of self-citation and co-authorship.

Serum uric acid and metabolic risk

OBJECTIVES

This review presents the information available on the role of uric acid (UA) on metabolic risk and on the link between hyperuricemia and metabolic syndrome.

METHODS

Key papers for inclusion were identified by a PubMed search and articles were selected according to their relevance for the topic, according to the authors' judgment.

RESULTS AND CONCLUSIONS

An elevated UA is both strongly associated and predictive of the metabolic syndrome, and increasing evidence suggests that UA may have a causal role. The classical viewpoint that UA is simply an innocuous marker of metabolic syndrome that should not even be measured will likely have to be modified. Lowering UA may be a novel treatment target for preventing diabetes and justify prospective clinical trials on the possible benefits of the measurement and lowering of serum UA on multiple chronic disease end points.

Prevalence of gout and hyperuricemia in the US general population: the National Health and Nutrition Examination Survey 2007-2008

OBJECTIVE

To estimate the prevalence of gout and hyperuricemia based on the latest nationally representative sample of US men and women (National Health and Nutrition Examination Survey [NHANES] 2007-2008).

METHODS

Using data from 5,707 participants in NHANES 2007-2008, we estimated the prevalence of gout and hyperuricemia. During home interviews for NHANES 2007-2008, all participants were asked about a history of health professional- or physician-diagnosed gout. Our primary definition of hyperuricemia was a serum urate level of >7.0 mg/dl for men and >5.7 mg/dl for women. We explored potential secular trends in these estimates and their possible explanations by comparing them with estimates based on 18,825 participants in NHANES-III (1988-1994).

RESULTS

The prevalence of gout among US adults in 2007-2008 was 3.9% (8.3 million individuals). The prevalence among men was 5.9% (6.1 million), and the prevalence among women was 2.0% (2.2 million). The mean serum urate levels were 6.14 mg/dl among men and 4.87 mg/dl among women, corresponding to hyperuricemia prevalences of 21.2% and 21.6%, respectively. These estimates were higher than those in NHANES-III, with differences of 1.2% in the prevalence of gout (95% confidence interval [95% CI] 0.6, 1.9), 0.15 mg/dl in the serum urate level (95% CI 0.07, 0.24), and 3.2% in the prevalence of hyperuricemia (95% CI 1.2, 5.2). These differences were substantially attenuated after adjusting for body mass index and/or hypertension.

CONCLUSION

These findings from nationally representative samples of US adults suggest that the prevalence of both gout and hyperuricemia remains substantial and may have increased over the past 2 decades, which is likely related to increasing frequencies of adiposity and hypertension.

Dietary, anthropometric, and biochemical determinants of uric acid in free-living adults

BACKGROUND

High plasma uric acid (UA) is a prerequisite for gout and is also associated with the metabolic syndrome and its components and consequently risk factors for cardiovascular diseases. Hence, the management of UA serum concentrations would be essential for the treatment and/or prevention of human diseases and, to that end, it is necessary to know what the main factors that control the uricemia increase. The aim of this study was to evaluate the main factors associated with higher uricemia values analyzing diet, body composition and biochemical markers.

METHODS

415 both gender individuals aged 21 to 82 years who participated in a lifestyle modification project were studied. Anthropometric evaluation consisted of weight and height measurements with later BMI estimation. Waist circumference was also measured. The muscle mass (Muscle Mass Index - MMI) and fat percentage were measured by bioimpedance. Dietary intake was estimated by 24-hour recalls with later quantification of the servings on the Brazilian food pyramid and the Healthy Eating Index. Uric acid, glucose, triglycerides (TG), total cholesterol, urea, creatinine, gamma-GT, albumin and calcium and HDL-c were quantified in serum by the dry-chemistry method. LDL-c was estimated by the Friedewald equation and ultrasensitive C-reactive protein (CRP) by the immunochemiluminiscence method. Statistical analysis was performed by the SAS software package, version 9.1. Linear regression (odds ratio) was performed with a 95% confidence interval (CI) in order to observe the odds ratio for presenting UA above the last quartile (♂UA > 6.5 mg/dL and ♀ UA > 5 mg/dL). The level of significance adopted was lower than 5%.

RESULTS

Individuals with BMI ≥ 25 kg/m2 OR = 2.28(1.13-4.6) and lower MMI OR = 13.4 (5.21-34.56) showed greater chances of high UA levels even after all adjustments (gender, age, CRP, gamma-gt, LDL, creatinine, urea, albumin, HDL-c, TG, arterial hypertension and glucose). As regards biochemical markers, higher triglycerides OR = 2.76 (1.55-4.90), US-CRP OR = 2.77 (1.07-7.21) and urea OR = 2.53 (1.19-5.41) were associated with greater chances of high UA (adjusted for gender, age, BMI, waist circumference, MMI, glomerular filtration rate, and MS). No association was found between diet and UA.

CONCLUSIONS

The main factors associated with UA increase were altered BMI (overweight and obesity), muscle hypotrophy (MMI), higher levels of urea, triglycerides, and CRP. No dietary components were found among uricemia predictors.

Plasma uric acid is associated with increased risk of type 2 diabetes independent of diet and metabolic risk factors

Current evidence suggests a direct association of uric acid with diabetes risk, but it is still unclear whether this is independent of risk factors such as obesity and diet. We aimed to investigate whether plasma uric acid concentrations are independently associated with incident type 2 diabetes and to investigate the role of a uric acid-related dietary pattern in this association. We used a case-cohort nested in the European Prospective Investigation into Cancer and Nutrition-Netherlands study. The study included 2318 subcohort members and 845 incident diabetes cases, with a mean follow-up of 10 y. At baseline, blood samples were taken and diet was assessed using a validated FFQ. A uric acid-related dietary pattern was derived with reduced rank regression. Diabetes was mainly self-reported and verified against general practitioner records. Plasma uric acid was (mean ± SD) 231 ± 54.6 μmol/L in the subcohort. After adjustment for established diabetes risk factors such as age, the HR (highest vs. lowest quartile of uric acid) for diabetes was 4.36 (95% CI: 3.22, 5.90). Further adjustment for adiposity attenuated the HR to 1.86 (95% CI: 1.32, 2.62). Additional adjustment for hypertension and biochemical markers, such as TG, slightly attenuated the association [HR = 1.43 (95% CI: 0.97, 2.10)]. A uric acid-related dietary pattern did not confound the association. In conclusion, this study supports that high uric acid concentrations are associated with increased diabetes risk, although a large part of the association can be explained by the degree of adiposity.

Alcohol intake and the risk of hyperuricaemia: a 6-year prospective study in Japanese men

BACKGROUND AND AIMS

Since there is little information derived from prospective studies on the amount of alcohol drinking required to induce hyperuricaemia, we attempted to address this issue in a Japanese population.

METHODS AND RESULTS

A total of 3310 Japanese men aged 20-54 years that were free of hyperuricaemia were classified according to their alcohol intake per week at baseline. Incident hyperuricaemia, defined as >7.0 mg/dl and/or taking medication for hyperuricaemia, was assessed through annual heath examinations for 6 years after the baseline examination. During follow-up, 529 incident cases of hyperuricaemia occurred. There was a positive, dose-response relationship between alcohol intake and the risk of incident hyperuricaemia. The hazard ratio (95% confidence interval) for hyperuricaemia in drinkers compared with non-drinkers was 1.10 (0.85-1.42) for <10.0 drinks/week, 1.40 (1.07-1.84) for 10.0-19.9 drinks/week, 1.64 (1.23-2.21) for 20.0-29.9 drinks/week and 1.98 (1.40-2.80) for ≥30.0 drinks/week (one drink contained 11.5 g of ethanol) after adjusting for age, baseline serum uric acid, body mass index, smoking habits, exercise habits, serum creatinine, blood pressure, serum cholesterol and blood glucose. The fraction of hyperuricaemia in the population attributable to alcohol intake was 21.6%. A clear dose-response pattern was observed for both beer and sake, when the consumption of these two beverages was analysed separately.

CONCLUSION

Habitual alcohol intake significantly contributed to the development of hyperuricaemia in Japanese men, regardless of type of alcoholic beverage consumed. Therefore, it is essential to reduce excessive alcohol intake to prevent and manage hyperuricaemia.

Caffeine intake and risk of urinary incontinence progression among women

OBJECTIVE

To estimate the association between long-term caffeine intake and risk of urinary incontinence (UI) progression over 2 years among women with moderate UI.

METHODS

We conducted a prospective cohort study in 21,564 women with moderate UI enrolled in the Nurses' Health Study and Nurses' Health Study II. Incontinence progression was identified from questionnaires during 2 years of follow-up. Baseline caffeine intake (ie, average intake during the previous year) and change in caffeine intake during the 4 years before baseline were measured using food frequency questionnaires. Odds ratios (ORs) for incontinence progression according to caffeine intake were calculated for each cohort separately, and then for both cohorts combined.

RESULTS

The percentage of women with UI progression was similar across categories of baseline level of caffeine intake and change in caffeine intake before baseline. For example, percentages were 21% compared with 22% comparing 450 mg or more to less than 150 mg of caffeine per day (adjusted OR 0.87, 95% confidence interval 0.70-1.08). Comparing women with increased caffeine intake to those with stable caffeine intake, percentages with progression were 22% compared with 20% (OR 1.08, 95% confidence interval 0.95-1.22). Results were similar in separate analyses of urge and stress UI.

CONCLUSION

Long-term caffeine intake over 1 year was not associated with risk of UI progression over 2 years among women with moderate incontinence, although we could not examine acute effects of caffeine. Improved understanding of the effect of caffeine on the bladder is needed to better-advise women with incontinence about caffeine intake.

LEVEL OF EVIDENCE

II.

Adherence to the Mediterranean diet and serum uric acid: the ATTICA study

OBJECTIVE

The present study aimed to explore potential associations between adherence to a Mediterranean diet and serum uric acid (UA) levels.

METHODS

The sample consisted of 2380 men and women free of cardiovascular or renal disease who participated in the ATTICA study. Dietary intake was assessed using a food frequency questionnaire (FFQ) and adherence to the Mediterranean diet was evaluated with the MedDietScore. Serum UA was measured and hyperuricaemia was defined as UA concentration > 7.0 mg/dL in men or > 6.0 mg/dL in women.

RESULTS

MedDietScore was inversely associated with UA levels (b-coefficient per quartile of the score = -0.07 ± 0.03, p = 0.02) independently of sex, presence of overweight, hypertension, or abnormal glucose metabolism, and alcohol or coffee intake. Those at the fourth quartile of MedDietScore had a 70% lower likelihood of having hyperuricaemia [odds ratio (OR) 0.30, 95% confidence interval (CI) 0.11-0.82] compared to those at the first quartile, after adjustment for several confounders. According to stratified analyses by sex, body mass index (BMI) status, hypertension, abnormal glucose, alcohol and coffee intake, the inverse association between serum UA and MedDietScore remained significant in women (b-coefficient = -0.194 ± 0.055, p < 0.001), overweight subjects (b-coefficient = -0.103 ± 0.047, p = 0.02), in those with normal glucose metabolism (b-coefficient = -0.074 ± 0.037, p = 0.04), and in those abstaining from alcohol (b-coefficient = -0.212 ± 0.073, p = 0.004) and coffee (b-coefficient = -0.221 ± 0.096, p = 0.02).

CONCLUSION

Adherence to the Mediterranean diet is associated with lower serum UA levels and lower likelihood of hyperuricaemia. These findings support a potential role of this dietary pattern in the prevention and treatment of hyperuricaemia and gout.

Caffeine attenuates metabolic syndrome in diet-induced obese rats

OBJECTIVE

Caffeine is a constituent of many non-alcoholic beverages. Pharmacological actions of caffeine include the antagonism of adenosine receptors and the inhibition of phosphodiesterase activity. The A₁ adenosine receptors present on adipocytes are involved in the control of fatty acid uptake and lipolysis. In this study, the effects of caffeine were characterized in a diet-induced metabolic syndrome in rats.

METHODS

Rats were given a high-carbohydrate, high-fat diet (mainly containing fructose and beef tallow) for 16 wk. The control rats were given a corn starch diet. Treatment groups were given caffeine 0.5 g/kg of food for the last 8 wk of the 16-wk protocol. The structure and function of the heart and the liver were investigated in addition to the metabolic parameters including the plasma lipid components.

RESULTS

The high-carbohydrate, high-fat diet induced symptoms of metabolic syndrome, including obesity, dyslipidemia, impaired glucose tolerance, decreased insulin sensitivity, and increased systolic blood pressure, associated with the development of cardiovascular remodeling and non-alcoholic steatohepatitis. The treatment with caffeine in the rats fed the high-carbohydrate, high-fat diet decreased body fat and systolic blood pressure, improved glucose tolerance and insulin sensitivity, and attenuated cardiovascular and hepatic abnormalities, although the plasma lipid concentrations were further increased.

CONCLUSION

Decreased total body fat, concurrent with increased plasma lipid concentrations, reflects the lipolytic effects of caffeine in adipocytes, likely owing to the caffeine antagonism of A₁ adenosine receptors on adipocytes.

Recent advances in management of gout

Incidence and prevalence of gout have markedly increased over the last few decades in keeping with the rise in prevalence of obesity and metabolic syndrome. Until recently, management of gout in patients with associated metabolic syndrome and comorbid illnesses such as renal impairment was difficult because of limited treatment options. However, significant progress has been made in the last few years, with introduction of new treatments such as interleukin-1 antagonists for management of acute gout, and febuxostat and pegloticase for chronic gout. The association of gout with alcohol, dietary purines and fructose ingestion has been confirmed in large prospective studies, thus enabling the clinician to now provide evidence-based advice to patients. Recent efficacy and safety data favour lower over higher doses of colchicine, and oral corticosteroids over non-steroidal anti-inflammatory drugs for patients with acute gout. Local ice therapy might help to differentiate gout from other forms of inflammatory arthritis, and supplementation with vitamin C help to reduce risk of gout. Several other drugs with rational mechanisms of action are in the pipeline, and likely to be introduced over the next few years. A new era has thus begun in the field of gout.

High plasma uric acid concentration: causes and consequences

High plasma uric acid (UA) is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides) in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer) seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease.

Serum urate in chronic gout--will it be the first validated soluble biomarker in rheumatology?

OBJECTIVE

To summarize evidence for and endorsement of serum urate (SU) as having fulfilled the OMERACT filter as a soluble biomarker in chronic gout at the 2010 Outcome Measures in Rheumatology Meeting (OMERACT 10).

METHODS

Data were presented to support the use of SU as a soluble biomarker in chronic gout and specifically the ability to utilize it to predict future patient-reported outcomes.

RESULTS

SU was accepted as having fulfilled the OMERACT filter by 78% of voters. However, consensus was not obtained regarding its use as a soluble biomarker in chronic gout. Although the majority of the criteria for a soluble biomarker were fulfilled, the key criterion of association of the biomarker with outcomes was not agreed upon. It was agreed that the appropriate choice of endpoint must be linked to its clinical importance to the individual with the disorder and its temporal relationship to the intervention. Appropriate outcomes in chronic gout may therefore include gout flares, reduction in tophi, and patient-reported outcomes.

CONCLUSION

SU is a critical outcome measure. It has the potential to fulfil criteria for a soluble biomarker. Further analyses of existing data from randomized controlled trials will be required to determine whether SU can predict future important outcomes, in particular disability.

The epidemiology of uric acid and fructose

During the past few decades, the mean serum uric acid levels and the prevalence of hyperuricemia in the general population appear to have increased. Correspondingly, the prevalence and incidence of gout have doubled. Potential reasons behind these trends include the increasing prevalence of obesity and metabolic syndrome, Western lifestyle factors, increased prevalence of medical conditions (eg, renal conditions, hypertension, and cardiovascular disorders), and use of medications that increase uric acid levels (eg, diuretics and low-dose aspirin). The substantial increase in sugar-sweetened soft drinks and associated fructose consumption also has coincided with the secular trend of hyperuricemia and gout. Recently, several large-scale epidemiologic studies have clarified a number of these long-suspected risk factors in relation with hyperuricemia and gout. Furthermore, recent studies have illuminated the substantial comorbidities of hyperuricemia and gout, particularly metabolic-cardiovascular-renal conditions. Although many prospective studies have suggested an independent association between serum uric acid levels and the future risk of cardiovascular-metabolic morbidities and mortality, only a limited number of randomized clinical trials and observational studies recently have shown that the use of allopurinol can be beneficial against these outcomes. Because these data are scarce and the effects of allopurinol might not be limited to decreasing serum uric acid levels, the potential causal role of uric acid on these outcomes remains to be clarified with further studies.

Coffee consumption and cystatin-C-based estimated glomerular filtration rates in healthy young adults: results of a clinical trial

Recently it has been reported that the estimated glomerular filtration rate (eGFR) is higher in habitual coffee consumers than in noncoffee consumers. However, the causality remains unclear. Therefore, we conducted a clinical trial to investigate the effects of coffee consumption on kidney function. Nineteen asymptomatic nonsmokers aged 21-27 years old participated in this study. They consumed coffee (18 g coffee beans/450 mL per day) or green tea as a comparator for 2 weeks in a crossover design. Although creatinine-based eGFR was not affected after consuming either beverage, all cystatin-C-based eGFRs determined using five different equations were significantly increased after coffee consumption (means: 5.0-7.7%), but not after green tea consumption (means: 0.1-1.6%). Serum adiponectin and magnesium levels increased significantly after coffee consumption (means: 13.6% and 4.3%, resp.), but not after green tea consumption. These findings suggest that even a short period of coffee consumption may increase cystatin-C-based eGFR, along with favorable changes in serum adiponectin, in healthy young adults.

[Treatment of gout]

In France, colchicine remains the standard treatment for the acute flare of gout. The lowest dose currently used decreases digestive toxicity. Doses of colchicine should be adapted to renal function and age, and possible drug interactions should be considered. Non steroidal anti-inflammatory drugs are an alternative to colchicine, but their use is frequently limited by comorbidity. When these treatments are contraindicated, corticosteroid injections can be performed after excluding septic arthritis. Systemic corticosteroids could be used in severe polyarticular flares. Anti-IL1 should provide a therapeutic alternative for severe cortico dependant gout with tophus. To prevent acute flares and reduce tophus volume, uric acid serum level should be reduced and maintained below 60mg/L (360μmol/L). To achieve this objective, it is often necessary to increase the daily dose of allopurinol above 300mgs, but the need to adapt the dose to renal function is a frequent cause of therapeutic failure. In the absence of renal stone or renal colic and hyperuraturia, uricosuric drugs are the second-line treatment. Probenecid is effective when creatinine clearance is superior to 50mL/min Benzbromarone, which was withdrawn due to hepatotoxicity, can be obtained on an individualized patient basis in the case of failure of allopurinol and probenecid. Febuxostat, which was recently approved, is a therapeutic alternative. Diuretics should be discontinued if possible. Use of fenofibrate should be discussed in the presence of dyslipidemia and losartan in patient with high blood pressure. Uricolytic drugs (pegloticase), which are currently being investigated, may be useful for the treatment of serious gout with tophus, especially in the presence of renal failure. Education of patient, identification and correction of cardiovascular risk factors should not be forgotten.

Risk factors for gout and prevention: a systematic review of the literature

PURPOSE OF REVIEW

Our objective was to perform a systematic review of risk factors and prevention of gout. We searched Medline for fully published reports in English using keywords including but not limited to 'gout', 'epidemiology', 'primary prevention', 'secondary prevention', 'risk factors'. Data from relevant articles meeting inclusion criteria were extracted using standardized forms.

RECENT FINDINGS

Of the 751 titles and abstracts, 53 studies met the criteria and were included in the review. Several risk factors were studied. Alcohol consumption increased the risk of incident gout, especially beer and hard liquor. Several dietary factors increased the risk of incident gout, including meat intake, seafood intake, sugar sweetened soft drinks, and consumption of foods high in fructose. Diary intake, folate intake, and coffee consumption were each associated with a lower risk of incident gout and in some cases a lower rate of gout flares. Thiazide and loop diuretics were associated with higher risk of incident gout and higher rate of gout flares. Hypertension, renal insufficiency, hypertriglyceridemia, hypercholesterolemia, hyperuricemia, diabetes, obesity, and early menopause were each associated with a higher risk of incident gout and/or gout flares.

SUMMARY

Several dietary risk factors for incident gout and gout flares are modifiable. Prevention and optimal management of comorbidities are likely to decreased risk of gout. Research in preventive strategies for the treatment of gout is needed.

Coffee, alcohol, smoking, physical activity and QT interval duration: results from the Third National Health and Nutrition Examination Survey

Background

Abnormalities in the electrocardiographic QT interval duration have been associated with an increased risk of ventricular arrhythmias and sudden cardiac death. However, there is substantial uncertainty about the effect of modifiable factors such as coffee intake, cigarette smoking, alcohol consumption, and physical activity on QT interval duration.

Methods

We studied 7795 men and women from the Third National Health and Nutrition Survey (NHANES III, 1988–1994). Baseline QT interval was measured from the standard 12-lead electrocardiogram. Coffee and tea intake, alcohol consumption, leisure-time physical activities over the past month, and lifetime smoking habits were determined using validated questionnaires during the home interview.

Results

In the fully adjusted model, the average differences in QT interval comparing participants drinking ≥6 cups/day to those who did not drink any were −1.2 ms (95% CI −4.4 to 2.0) for coffee, and −2.0 ms (−11.2 to 7.3) for tea, respectively. The average differences in QT interval duration comparing current to never smokers was 1.2 ms (−0.6 to 2.9) while the average difference in QT interval duration comparing participants drinking ≥7 drinks/week to non-drinkers was 1.8 ms (−0.5 to 4.0). The age, race/ethnicity, and RR-interval adjusted differences in average QT interval duration comparing men with binge drinking episodes to non-drinkers or drinkers without binge drinking were 2.8 ms (0.4 to 5.3) and 4.0 ms (1.6 to 6.4), respectively. The corresponding differences in women were 1.1 (−2.9 to 5.2) and 1.7 ms (−2.3 to 5.7). Finally, the average differences in QT interval comparing the highest vs. the lowest categories of total physical activity was −0.8 ms (−3.0 to 1.4).

Conclusion

Binge drinking was associated with longer QT interval in men but not in women. QT interval duration was not associated with other modifiable factors including coffee and tea intake, smoking, and physical activity.

Coffee consumption could affect the activity of some liver enzymes and other biochemical parameters in healthy drinkers

OBJECTIVE

To investigate the effect of coffee consumption on some liver function indices in adult male and female Nigerians.

SUBJECTS AND METHODS

Thirty apparently healthy subjects, consisting of 18 men and 12 women, were made to consume 2 g of coffee daily for a total of 30 days. Activities of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and plasma concentrations of total and conjugated bilirubin, total protein and albumin were determined using standard methods.

RESULTS

Relative to baseline values, coffee consumption raised mean levels of ALT by 4 IU/l (p < 0.001), AST by 2.0 1 U/l (p < 0.001), ALP by 3.0 1 U/l (p < 0.01), total bilirubin by 0.90 mg/dl (p < 0.05) and total protein by 1.1 g/l (p < 0.05). Gender differences were observed. Significantly higher mean ALP concentration was only seen in male subjects, while mean bilirubin concentration was significantly raised in female volunteers alone. On the other hand, the mean total protein and albumin concentrations in individual male and female groups were not significantly altered (p > 0.05 in each case).

CONCLUSION

The result obtained from the study suggests that short-term consumption of coffee might have a significant effect on the integrity of the liver function tests studied.

Role of diet in rheumatic disease

Millions of people suffer from rheumatic diseases such as gout, fibromyalgia, osteoarthritis, and rheumatoid arthritis. These can be incapacitating and detrimental to quality of life. Diet, nutrition, and weight loss have shown promise in alleviating some of this disease burden. These lifestyle changes may give patients a feeling of control and ownership over their disease as well as a nonpharmacologic means of treatment. This article reviews the available research on the effects of diet and nutrition on rheumatoid disease.

Coffee consumption and risk of incident gout in women: the Nurses' Health Study

BACKGROUND

Coffee is one of the most widely consumed beverages in the world and may affect the risk of gout via various mechanisms, but prospective data on the relation between coffee intake and the risk of incident gout are limited.

DESIGN

Over a 26-y period, we prospectively examined the relation between coffee intake and risk of incident gout in 89,433 female participants in the Nurses' Health Study. We assessed the consumption of coffee, decaffeinated coffee, tea, and total caffeine in participants every 2-4 y through validated questionnaires. We used a supplementary questionnaire to ascertain whether participants met the survey criteria of the American College of Rheumatology for gout.

RESULTS

During the 26 y of follow-up, we documented 896 confirmed incident cases of gout. There was an inverse association between higher coffee intake and the risk of gout. The multivariate relative risks (RRs) for incident gout according to coffee-consumption categories [ie, 0, 1-237, 238-947, and ≥948 mL coffee/d (237 mL = one 8-ounce cup)] were 1.00, 0.97, 0.78 (95% CI: 0.64, 0.95), and 0.43 (95% CI: 0.30, 0.61; P for trend < 0.0001), respectively. For decaffeinated coffee, the multivariate RRs according to consumption categories (0, 1-237, and ≥237 mL decaffeinated coffee/d) were 1.00, 1.02, and 0.77 (95% CI: 0.63, 0.95; P for trend = 0.02), respectively. There was an inverse association between total caffeine from all sources and the risk of gout; the multivariate RR of the highest quintile compared with the lowest quintile was 0.52 (95% CI: 0.41, 0.68; P for trend <0.0001).

CONCLUSION

These prospective data suggest that long-term coffee consumption is associated with a lower risk of incident gout in women.

The relation of coffee consumption to serum uric Acid in Japanese men and women aged 49-76 years

Objective. Few studies have suggested an inverse relation between coffee intake and serum concentrations of uric acid (UA), but none has addressed the relation in men and women separately. We examined the relation between coffee intake and serum UA levels in free-living middle-aged and elderly men and women in Fukuoka, Japan. Methods. Study subjects were derived from the baseline survey of a cohort study on lifestyle-related diseases, and included 11.662 men and women aged 49–76 years; excluded were those with medication for gout and hyperuricemia, use of diuretic drugs, and medical care for cancer or chronic kidney disease. Statistical adjustment was made for body mass index, alcohol use, hypertension, diabetes mellitus, and other factors. Results. There were inverse associations of coffee consumption with serum UA concentrations and hyperuricemia in men regardless of adjustment for covariates. Women showed a statistically significant, but weaker, inverse association between coffee and serum UA levels after allowance for the confounding factors. Conclusion. The findings add to evidence for a protective association between coffee intake and hyperuricemia.

Interactions between genetic variants in glucose transporter type 9 (SLC2A9) and dietary habits in serum uric acid regulation

AIM

To investigate possible interactions between genetic variants in glucose transporter type 9 (SLC2A9) gene and dietary habits in serum uric acid regulation.

METHODS

Participants for this study were recruited from two isolated Croatian island communities of Vis (n=918) and Korcula (n=898). Three single nucleotide polymorphisms (SNP) from the SLC2A9 gene (rs1014290, rs6449213, rs737267) were correlated with dietary habits and uric acid.

RESULTS

A significant decrease in uric acid levels was recorded with increasing consumption of milk, sour cream, duck and turkey, and eggs. The only significant interaction was found between potato consumption and rs737267 and a near-significant interaction was found between soft drinks and rs1014290 (interaction P=0.068). Increased consumption of soft drinks interacting with the TT genotype at rs1014290 increased serum uric acid. No significant interactions were observed between food products consumption and rs6449213.

CONCLUSION

There is a certain extent of interaction between SLC2A9 and dietary patterns in serum uric acid determination. The metabolic effect of soft drinks seems to be determined by the underlying genotype of rs1014290.

A prescription for lifestyle change in patients with hyperuricemia and gout

PURPOSE OF REVIEW

This review summarizes the recent data on lifestyle factors that influence serum uric acid levels and the risk of gout and attempts to provide holistic recommendations, considering both their impact on gout as well as on other health implications.

RECENT FINDINGS

Large-scale studies have clarified a number of long-suspected relations between lifestyle factors, hyperuricemia, and gout, including purine-rich foods, dairy foods, various beverages, fructose, and vitamin C supplementation. Furthermore, recent studies have identified the substantial burden of comorbidities among patients with hyperuricemia and gout.

SUMMARY

Lifestyle and dietary recommendations for gout patients should consider overall health benefits and risk, since gout is often associated with the metabolic syndrome and an increased future risk of cardiovascular disease (CVD) and mortality. Weight reduction with daily exercise and limiting intake of red meat and sugary beverages would help reduce uric acid levels, the risk of gout, insulin resistance, and comorbidities. Heavy drinking should be avoided, whereas moderate drinking, sweet fruits, and seafood intake, particularly oily fish, should be tailored to the individual, considering their anticipated health benefits against CVD. Dairy products, vegetables, nuts, legumes, fruits (less sugary ones), and whole grains are healthy choices for the comorbidities of gout and may also help prevent gout by reducing insulin resistance. Coffee and vitamin C supplementation could be considered as preventive measures as these can lower urate levels, as well as the risk of gout and some of its comorbidities.

N-acetyltransferase 2, exposure to aromatic and heterocyclic amines, and receptor-defined breast cancer

The role of N-acetyltransferase 2 (NAT2) polymorphism in breast cancer is still unclear. We explored the associations between potential sources of exposure to aromatic and heterocyclic amines (AHA), acetylation status and receptor-defined breast cancer in 1020 incident cases and 1047 population controls of the German GENICA study. Acetylation status was assessed as slow or fast. Therefore, NAT2 haplotypes were estimated using genotype information from six NAT2 polymorphisms. Most probable haplotypes served as alleles for the deduction of NAT2 acetylation status. The risks of developing estrogen receptor alpha (ER) and progesterone receptor (PR)-positive or negative tumors were estimated for tobacco smoking, consumption of red meat, grilled food, coffee, and tea, as well as expert-rated occupational exposure to AHA with logistic regression conditional on age and adjusted for potential confounders. Joint effects of these factors and NAT2 acetylation status were investigated. Frequent consumption of grilled food and coffee showed higher risks in slow acetylators for receptor-negative tumors [grilled food: ER-: odds ratio (OR) 2.57, 95% confidence interval (CI) 1.07-6.14 for regular vs. rare; coffee: ER-: OR 2.55, 95% CI 1.22-5.33 for >or=4 vs. 0 cups/day]. We observed slightly higher risks for never smokers that are fast acetylators for receptor-positive tumors compared with slow acetylators (ER-: OR 1.32, 95% CI 1.00-1.73). Our results support differing risk patterns for receptor-defined breast cancer. However, the modifying role of NAT2 for receptor-defined breast cancer is difficult to interpret in the light of complex mixtures of exposure to AHA.

Correlation of asymptomatic hyperuricaemia and serum uric acid levels with arterial stiffness in women with systemic lupus erythematosus without clinically evident atherosclerotic cardiovascular disease

The objective of this article was to evaluate whether serum uric acid (SUA) correlates with arterial stiffness and inflammation markers in a cohort of women with systemic lupus erythematosus (SLE) without overt atherosclerotic cardiovascular diseases, who attended a community hospital. One hundred and two women with SLE were assessed as part of this cross-sectional study. Carotid-femoral pulse wave velocity (PWV) was measured using an automatic device (Complior). C-reactive protein (CRP), fibrinogen and homocysteine levels as well as other metabolic results were recorded. Duration and activity of SLE, damage accrual and treatments were recorded. SLE women were categorized as having or not having hyperuricaemia (HU) according to SUA levels (greater than or up to 6.2 mg/dl, respectively). A multiple linear regression analysis was used to determine the independent link between SUA levels and other variables. Women with SLE and HU (n = 15, 15%) had a worse cardiovascular risk profile that included ageing, hypertension, obesity, higher total cholesterol levels, renal failure and presence of metabolic syndrome. Also, the duration of SLE was increased and damage accrual was greater. In the unadjusted analysis, SUA levels correlated with PWV, CRP, fibrinogen and homocysteine. However, in a multivariate linear regression analysis, SUA levels independently correlated with the duration of SLE, creatinine, total cholesterol and homocysteine levels but did not correlate with PWV. In conclusion, SUA was associated with arterial stiffness, but not independently of age and homocysteine levels. Nevertheless, SUA might be an ancillary indicator of subclinical atherosclerosis in SLE women without clinically evident atherosclerotic cardiovascular disease.

Update on gout and hyperuricemia

There have been recent advances in the understanding of underlying mechanisms and treatment of gout and chronic hyperuricemia, making this an important time to review the current state of the disease. The goal of this article is to provide a practical review of the current standard of care as well as discuss some new developments in the management. There is an increasing prevalence of gout and hyperuricemia worldwide. Gout confers a significant individual and societal burden and is often under-treated. Appropriate diagnosis and treatment of acute gout should be followed by aggressive and goal-oriented treatment of hyperuricemia and other risk factors. Allopurinol remains as a first-line treatment for chronic hyperuricemia, but uricosuric agents may also be considered in some patients. Febuxostat, a non-purine xanthine-oxidase inhibitor, is a new agent approved for the treatment of hyperuricemia in patients with gout, which may be used when allopurinol is contraindicated. Gout and hyperuricemia appear to be independent risk factors for incident hypertension, renal disease and cardiovascular disease. Physicians should consider cardiovascular risk factors in patients with gout and treat them appropriately and aggressively.

Gout

Gout is a common arthritis caused by deposition of monosodium urate crystals within joints after chronic hyperuricaemia. It affects 1-2% of adults in developed countries, where it is the most common inflammatory arthritis in men. Epidemiological data are consistent with a rise in prevalence of gout. Diet and genetic polymorphisms of renal transporters of urate seem to be the main causal factors of primary gout. Gout and hyperuricaemia are associated with hypertension, diabetes mellitus, metabolic syndrome, and renal and cardiovascular diseases. Non-steroidal anti-inflammatory drugs and colchicine remain the most widely recommended drugs to treat acute attacks. Oral corticosteroids could be an alternative to these drugs. Interleukin 1beta is a pivotal mediator of acute gout and could become a therapeutic target. When serum uric acid concentrations are lowered below monosodium urate saturation point, the crystals dissolve and gout can be cured. Patient education, appropriate lifestyle advice, and treatment of comorbidities are an important part of management of patients with gout.

Vitamin C intake and the risk of gout in men: a prospective study

BACKGROUND

Several metabolic studies and a recent double-blind, placebo-controlled, randomized trial have shown that higher vitamin C intake significantly reduces serum uric acid levels. Yet the relation with risk of gout is unknown.

METHODS

We prospectively examined, from 1986 through 2006, the relation between vitamin C intake and risk of incident gout in 46 994 male participants with no history of gout at baseline. We used a supplementary questionnaire to ascertain the American College of Rheumatology criteria for gout. Vitamin C intake was assessed every 4 years through validated questionnaires.

RESULTS

During the 20 years of follow-up, we documented 1317 confirmed incident cases of gout. Compared with men with vitamin C intake less than 250 mg/d, the multivariate relative risk (RR) of gout was 0.83 (95% confidence interval [CI], 0.71-0.97) for total vitamin C intake of 500 to 999 mg/d, 0.66 (0.52-0.86) for 1000 to 1499 mg/d, and 0.55 (0.38-0.80) for 1500 mg/d or greater (P < .001 for trend). The multivariate RR per 500-mg increase in total daily vitamin C intake was 0.83 (95% CI, 0.77-0.90). Compared with men who did not use supplemental vitamin C, the multivariate RR of gout was 0.66 (95% CI, 0.49-0.88) for supplemental vitamin C intake of 1000 to 1499 mg/d and 0.55 (0.36-0.86) for 1500 mg/d or greater (P < .001 for trend).

CONCLUSIONS

Higher vitamin C intake is independently associated with a lower risk of gout. Supplemental vitamin C intake may be beneficial in the prevention of gout.

Hypothesis: could excessive fructose intake and uric acid cause type 2 diabetes?

We propose that excessive fructose intake (>50 g/d) may be one of the underlying etiologies of metabolic syndrome and type 2 diabetes. The primary sources of fructose are sugar (sucrose) and high fructose corn syrup. First, fructose intake correlates closely with the rate of diabetes worldwide. Second, unlike other sugars, the ingestion of excessive fructose induces features of metabolic syndrome in both laboratory animals and humans. Third, fructose appears to mediate the metabolic syndrome in part by raising uric acid, and there are now extensive experimental and clinical data supporting uric acid in the pathogenesis of metabolic syndrome. Fourth, environmental and genetic considerations provide a potential explanation of why certain groups might be more susceptible to developing diabetes. Finally, we discuss the counterarguments associated with the hypothesis and a potential explanation for these findings. If diabetes might result from excessive intake of fructose, then simple public health measures could have a major impact on improving the overall health of our populace.

Lifestyle and gout

PURPOSE OF REVIEW

This review summarizes recent epidemiologic research findings on gout, and attempts to put them into the context of clinical and public health decision-making aimed at prevention and improved management of gout.

RECENT FINDINGS

A large prospective study found that coffee consumption was inversely associated with risk of gout and that consumption of sugar-sweetened soft drinks or fructose was strongly associated with an increased gout risk. Studies based on the Third National Health and Nutrition Examination Survey (NHANES III) suggest that these consumptions affect serum uric acid levels parallel to the direction of gout risk. Furthermore, data from NHANES III show a remarkably high prevalence of the metabolic syndrome among individuals with gout. Prospective studies found an increased risk of myocardial infarction and cardiovascular mortality in gout patients.

SUMMARY

Lifestyle and dietary recommendations for gout patients should consider other health benefits, since gout is often associated with major chronic disorders such as the metabolic syndrome and an increased risk for cardiovascular disease and mortality. In addition to recent dietary recommendations, gout patients should be advised to limit fructose intake. The inverse link between coffee and the risk of gout suggests that coffee could be allowed among gout patients.

Diet, urate, and Parkinson's disease risk in men

The authors examined whether a diet that increases plasma urate level is also related to reduced risk of Parkinson's disease (PD). The study population comprised 47,406 men in the Health Professionals Follow-up Study. The potential effect of diet on plasma urate level was estimated by regressing plasma urate on intakes of selected foods and nutrients in a subsample of 1,387 men. Coefficients of this regression model were then used to calculate a dietary urate index for all cohort participants. Multivariate relative risks of PD were estimated by means of Cox proportional hazards models. After 14 years of follow-up (1986-2000), the authors documented 248 incident cases of PD. A higher dietary urate index was associated with a lower risk of PD (top quintile vs. bottom: relative risk = 0.47, p-trend = 0.0008), after adjustment for age, smoking, caffeine intake, and other potential confounders. This association remained strong and significant after further adjustment for each component of the index individually (p-trend < 0.02 for each). These data support urate as a potentially protective factor in PD and suggest that dietary changes expected to increase plasma urate level may contribute to lower risk of PD. These potential benefits, however, should be weighed against expected adverse effects on risk of gout and other chronic diseases.

Soft drinks, fructose consumption, and the risk of gout in men: prospective cohort study

OBJECTIVE

To examine the relation between intake of sugar sweetened soft drinks and fructose and the risk of incident gout in men.

DESIGN

Prospective cohort over 12 years.

SETTING

Health professionals follow-up study.

PARTICIPANTS

46 393 men with no history of gout at baseline who provided information on intake of soft drinks and fructose through validated food frequency questionnaires.

MAIN OUTCOME MEASURE

Incident cases of gout meeting the American College of Rheumatology survey criteria for gout.

RESULTS

During the 12 years of follow-up 755 confirmed incident cases of gout were reported. Increasing intake of sugar sweetened soft drinks was associated with an increasing risk of gout. Compared with consumption of less than one serving of sugar sweetened soft drinks a month the multivariate relative risk of gout for 5-6 servings a week was 1.29 (95% confidence interval 1.00 to 1.68), for one serving a day was 1.45 (1.02 to 2.08), and for two or more servings a day was 1.85 (1.08 to 3.16; P for trend=0.002). Diet soft drinks were not associated with risk of gout (P for trend=0.99). The multivariate relative risk of gout according to increasing fifths of fructose intake were 1.00, 1.29, 1.41, 1.84, and 2.02 (1.49 to 2.75; P for trend <0.001). Other major contributors to fructose intake such as total fruit juice or fructose rich fruits (apples and oranges) were also associated with a higher risk of gout (P values for trend <0.05).

CONCLUSIONS

Prospective data suggest that consumption of sugar sweetened soft drinks and fructose is strongly associated with an increased risk of gout in men. Furthermore, fructose rich fruits and fruit juices may also increase the risk. Diet soft drinks were not associated with the risk of gout.