Menopause, postmenopausal hormone use and serum uric acid levels in US women--the Third National Health and Nutrition Examination Survey

Uric acid as one of the important factors in multifactorial disorders--facts and controversies

With considering serum concentration of the uric acid in humans we are observing hyperuricemia and possible gout development. Many epidemiological studies have shown the relationship between the uric acid and different disorders such are obesity, metabolic syndrome, hypertension and coronary artery disease. Clinicians and investigators recognized serum uric acid concentration as very important diagnostic and prognostic factor of many multifactorial disorders. This review presented few clinical conditions which are not directly related to uric acid, but the concentrations of uric acid might have a great impact in observing, monitoring, prognosis and therapy of such disorders. Uric acid is recognized as a marker of oxidative stress. Production of the uric acid includes enzyme xanthine oxidase which is involved in producing of radical-oxigen species (ROS). As by-products ROS have a significant role in the increased vascular oxidative stress and might be involved in atherogenesis. Uric acid may inhibit endothelial function by inhibition of nitric oxide-function under conditions of oxidative stress. Down regulation of nitric oxide and induction of endothelial dysfunction might also be involved in pathogenesis of hypertension. The most important and well evidenced is possible predictive role of uric acid in predicting short-term outcome (mortality) in acute myocardial infarction (AMI) patients and stroke. Nephrolithiasis of uric acid origin is significantly more common among patients with the metabolic syndrome and obesity. On contrary to this, uric acid also acts is an “antioxidant”, a free radical scavenger and a chelator of transitional metal ions which are converted to poorly reactive forms.

Reproductive factors and serum uric acid levels in females from the general population: the KORA F4 study

Objective

Hyperuricemia is associated with an increased risk of metabolic and cardiovascular diseases. There are pronounced sex differences in the levels of uric acid. It is largely unknown whether or not reproductive parameters which induce hormonal changes are responsible for this. We examined if there are associations between reproductive parameters and uric acid levels in a female population-based sample.

Methods

In this cross-sectional analysis, data of 1530 women aged 32 to 81 years participating in the KORA F4 study, conducted between 2006 and 2008 in Southern Germany were used. Reproductive parameters were obtained by standardized interviews. Uric acid levels were tested by the uricase method. The whole study sample and stratified in pre- and postmenopausal women was analyzed.

Results

Menopausal status and earlier age at menarche were associated with higher serum uric acid levels (age-adjusted: p-values 0.003, <0.001 respectively; after multivariable adjustment, including BMI: p-values 0.002, 0.036). A history of oral contraceptive use showed an association with uric acid levels only after multivariable adjustment (p-value 0.009). Hot flushes showed an association with uric acid levels only after age-adjustment (p-value 0.038), but lost significance after adding other confounders. Other reproductive factors, including parity, current or ever use of hormone replacement therapy, current use of oral contraceptives, hysterectomy, bilateral oophorectomy, or depressive mood related to menopausal transition were not associated with uric acid levels.

Conclusions

Postmenopausal status, earlier age at menarche and a history of oral contraceptive use were independently associated with higher serum uric acid concentrations in women from the general population. Further studies, especially longitudinal population-based studies investigating the relationship of female reproductive parameters with uric acid levels are necessary to confirm our findings.

The relationship between the regional abdominal adipose tissue distribution and the serum uric acid levels in people with type 2 diabetes mellitus

BACKGROUND

Hyperuricemia is associated with obesity. The visceral adiposity and subcutaneous adiposity may be associated with the differential metabolic risk, and the distribution of abdominal adipose tissue was significantly altered in people with type 2 diabetes mellitus (DM) compared to healthy people. Our study was performed to determine to the association between the regional abdominal adipose tissue distribution and serum uric acid levels in people with type 2 DM.

METHODS

A total of 699 people with type 2 DM and who had undergone abdominal computed tomography assessment of the visceral fat area and subcutaneous fat area were included. The serum uric acid levels were measured by the uricase method. Hyperuricemia was defined by cut-off value of > 7 mg/dl for men and > 6 mg/dl for women.

RESULTS

The visceral fat area was positively associated with the serum uric acid levels after adjustment for age, sex, systolic blood pressure, diastolic blood pressure, serum creatinine, hemoglobin, serum albumin, serum high-density lipoprotein, serum triglyceride and hemoglobin A1c (β-coefficient = 0.117, p < 0.001). The logistic regression analysis showed that the visceral fat area was the significant independent predictor of hyperuricemia (OR 2.33, 95% CI, 1.21-4.50, p = 0.012). But there was no significant association between the subcutaneous fat area and the serum uric acid levels (β-coefficient = 0.061, p = 0.255).

CONCLUSIONS

our data shows that the visceral fat area was positively associated with the serum uric acid levels, but the subcutaneous fat area was not in people with type 2 DM.

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.

Increased risk of cancer among gout patients: a nationwide population study

OBJECTIVE

Few studies have investigated the association between gout and cancer. The present study examined the relative risk of cancer in a nationwide cohort.

METHODS

The primary data source was the National Health Insurance database of Taiwan. Data recorded between 2000 and 2008 for subjects ≥20 years and with no history of malignancy were included for the analysis. A gout case definition was defined by records of gout diagnosis and anti-gout treatment (urate-lowering drugs, including allopurinol, benzbromazone, probenacid and sulfinpyrazone, and colchicine). Cox proportional hazards models were used to examine the association between gout and cancer.

RESULTS

A total of 694,361 patients (355,278 men, 339,083 women) were included; among them, 25,943 had a history of gout. Mean age (±standard deviation) was 42.3±16.3 years. During 5,471,272 patient-years of follow-up, cancer was detected in 24,088 patients (1745 with gout and 22,343 controls). The most cancers were liver, lung, and colonic cancers. The overall incidence of cancer was significantly higher among gout patients than controls (8.7 vs. 4.2 cases per 1000 patient-years, P<0.001). After adjustment for age and sex, gout was found to be associated with a hazard ratio (HR) of 1.15 (95% confidence interval [CI], 1.10-1.21; P<0.001) for cancer. Gout was most closely associated with prostate cancer, with an age- and sex-adjusted HR of 1.71 (1.45-2.02). On the other hand, gout tended to have an inverse, albeit insignificant, association with breast cancer (adjusted HR, 0.81; 95% CI, 0.63-1.04).

CONCLUSION

Gout was associated with increased risk of cancer, particularly that of prostate cancer in males.

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.

Significant association of serum uric acid levels with SLC2A9 rs11722228 among a Japanese population

Genome-wide association studies identified that SLC2A9 (GLUT9) gene polymorphisms were associated with serum uric acid (SUA) levels. Among the Japanese, a C/T polymorphism in intron 8 (rs11722228) was reported to be highly significant, though the function and strength of association were unknown. This study aimed to confirm the association, estimating the means of SUA according to the genotype, as well as OR of the genotype. Subjects were 5024 health checkup examinees (3413 males and 1611 females) aged 35 to 69 years with creatinine <2.0 mg/dL. Since SLC22A12 258X allele and ABCG2 126X allele are known to influence SUA levels strongly, the subjects with SLC22A12 258WW and ABCG2 126QQ (3082 males and 1453 females, in total 4535 subjects) were selected. The genotype frequency of SLC2A9 rs11722228 was 2184 for CC, 1947 for CT, and 404 for TT, being in Hardy-Weinberg equilibrium (p=0.312). Mean SUA was 6.10 mg/dL for CC, 6.25 mg/dL for CT, and 6.45 mg/dL for TT among males (p=1.5E-6), and 4.34 mg/dL, 4.59 mg/dL, and 4.87 mg/dL among females (p=4.6E-11), respectively. Males with SUA less than 5.0 mg/dL were 14.7% for CC, 10.6% for CT, and 7.8% for TT (p=2.3E-4), and females with SUA less than 4.0 mg/dL were 34.1%, 25.5%, and 15.4% (p=3.7E-6), respectively. This study was the first report to estimate the impact of SLC2A9 rs11722228 on SUA levels. Since the allele frequency of rs11722228 is similar among different ethnic groups, the impact remains to be examined in other ethnic groups.

[The epidemiology and genetic of gout]

Gout 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 the prevalence of gout. Diet and genetic predisposition 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. Genetic studies have found that variants of GLUT9 and ABCG2 were associated with urate levels.

The independent impact of congestive heart failure status and diuretic use on serum uric acid among men with a high cardiovascular risk profile: a prospective longitudinal study

OBJECTIVE

To evaluate the independent impact of congestive heart failure (CHF) status (compensation or decompensation) on serum uric acid levels among men with high cardiovascular risk profile.

METHOD

We analyzed 11,681 men from the Multiple Risk Factor Interventional Trial, using data prospectively collected at baseline and annually over 6 years (64,644 visits). We evaluated the impact of change in CHF status during study follow-up, as compared with study baseline, on hyperuricemia (serum uric acid ≥7 mg/dL) and serum uric acid levels, using generalized estimating equations, adjusting for age, race, weight, weight change, education, alcohol intake, diuretic use, hypertension, serum creatinine level, and dietary factors. Similarly, we evaluated the independent impact of change in diuretic use (initiation or discontinuation).

RESULTS

At baseline, mean serum uric acid was 6.88 mg/dL. Compared with no change in CHF status, odds ratios of hyperuricemia were 1.67 (95% CI, 1.21 to 2.32) for CHF decompensation and 0.21 (95% CI, 0.08 to 0.55) for compensation. The corresponding uric acid differences were 0.41 (95% CI, 0.20 to 0.62) and -1.00 (95% CI, -1.72 to -0.27), respectively. The odds ratios for initiation and discontinuation of diuretic were 3.32 (95% CI, 3.06 to 3.61) and 0.39 (95% CI, 0.35 to 0.44).

CONCLUSIONS

CHF decompensation and diuretic use are both independently associated with increased odds of hyperuricemia among men with a high cardiovascular risk profile, whereas CHF recovery and diuretic discontinuation are associated with substantially lower odds of hyperuricemia.

Contemporary epidemiology of gout in the UK general population

Introduction

The objective of this study was to investigate the contemporary incidence of gout, examine potential risk factors, and evaluate specific gout treatment patterns in the general population.

Methods

Using the health improvement network (THIN) UK primary care database, we estimated the incidence of gout based on 24,768 newly diagnosed gout patients among a cohort of 1,775,505 individuals aged 20 to 89 years between 2000 and 2007. We evaluated potential risk factors for incident gout in a nested case-control study with 50,000 controls frequency-matched by age, sex and calendar time. We calculated odds ratios (OR) by means of unconditional logistic regression adjusting for demographic variables, lifestyle variables, relevant medical conditions and drug exposures.

Results

The incidence of gout per 1,000 person-years was 2.68 (4.42 in men and 1.32 in women) and increased with age. Conventional risk factors were significantly and strongly associated with the risk of gout, with multivariate ORs of 3.00 (95% confidence interval (CI)) for excessive alcohol intake (that is, more than 42 units per week), 2.34 (95% CI 2.22 to 2.47) for obesity (body mass index > = 30 kg/m²), 2.48 (95% CI 2.19 to 2.81) for chronic renal impairment, and 3.00 (95% CI 2.85 to 3.15) for current diuretic use. For other medical conditions the multivariate OR were 1.84 (95% CI 1.70 to 2.00) for heart failure, 1.45 (95% CI 1.18 to 1.79) for hypertriglyceridemia and 1.12 (95% CI 1.04 to 1.22) for psoriasis. Use of cyclosporine was associated with an OR of 3.72 (95% CI, 2.17 to 6.40). Among gout-specific therapies, allopurinol was the most frequently used with a one-year cumulative incidence of 28% in a cohort of incident gout diagnosed from 2000 to 2001. Use of gout-specific treatment has not changed over recent years except for an increase of colchicine.

Conclusions

The contemporary incidence of gout in UK remains substantial. In this general population cohort, associations with previously purported risk factors were evident including psoriasis, heart failure, hypertriglyceridemia, and cyclosporine therapy. Use of gout-specific treatment has remained relatively constant in recent years except for an increase of colchicine.

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.

Increased blood oxidative stress in experimental menopause rat model: the effects of vitamin A low-dose supplementation upon antioxidant status in bilateral ovariectomized rats

Menopause has been reported to be associated with increased oxidative stress and metabolic disorders among women worldwide. Disarrangements in the redox state similar to those observed in women during the decline of ovarian hormonal activity can be obtained experimentally through rat bilateral ovariectomy. The search for alternative treatments to improve life quality in postmenopausal woman is really important. The aim of this study was to evaluate biochemical and oxidative stress parameters that distinguish sham-operated female rats from Wistar rats bilaterally ovariectomized (OVX). Additionally, we have also investigated the effects of retinol palmitate (a vitamin A supplement) low-dose supplementation (500 or 1500 IU/kg/day, during 30 days) upon blood and plasma antioxidant status in OVX rats. Ovariectomy caused an increase in body weight gain, pronounced uterine atrophy, decreased plasma triglycerides and increased total cholesterol levels, and reduced acid uric content. Moreover, we found increased blood peroxidase activities (catalase and glutathione peroxidase), decreased plasma non-enzymatic antioxidant defenses total reactive antioxidant potential and total antioxidant reactivity, decreased protein and non-protein SH levels, accompanied by increased protein oxidative damage (carbonyl). In addition, vitamin A low-dose supplementation was capable to ameliorate antioxidant status in OVX rats, restoring both enzymatic and non-enzymatic defenses, promoting reduction in plasma SH content, and decreasing protein oxidative damage levels. This is the first work in the literature showing that vitamin A at low dose may be beneficial in the treatment of menopause symptoms. Further studies will be made to better understand the effects of vitamin A supplementation in menopause rat model.

Plasma urate and Parkinson's disease in women

Plasma urate has been consistently associated with a lower risk of Parkinson's disease in men, but it is less clear if this relation exists in women. Between 1990 and 2004, the authors conducted a nested case-control study among participants of the female-only Nurses' Health Study. In controls (n = 504), plasma urate was positively associated with age, body mass index, alcohol consumption, hypertension, and use of diuretics and was inversely associated with physical activity and postmenopausal hormone use, as expected. Mean urate levels were 5.04 mg/dL for cases (n = 101) and 4.86 mg/dL for controls (P = 0.17). The age-, smoking-, and caffeine-adjusted rate ratio comparing women in the highest (≥5.8 mg/dL) with those in the lowest (<4.0 mg/dL) quartile was 1.33 (95% confidence interval: 0.69, 2.57; P(trend) = 0.4). Further adjustment for body mass index, physical activity, history of hypertension, and postmenopausal hormone use did not change the results. Unlike in men, these findings do not support the hypothesis that urate is strongly associated with lower rates of Parkinson's disease among women.

The serum urate-lowering impact of weight loss among men with a high cardiovascular risk profile: the Multiple Risk Factor Intervention Trial

OBJECTIVES

To evaluate the person-level impact of weight loss on serum urate levels among men with a high cardiovascular risk profile.

METHODS

We analysed 12,379 men (mean serum urate level=407 μmol/l) from the Multiple Risk Factor Intervention Trial, using data prospectively collected at baseline and annually over a 7-year period (78,881 visits). Our endpoint was normouricaemia, defined by serum urate levels≤360 μmol/l, a widely accepted therapeutic target. Person-level effects were estimated using conditional logistic regression models to adjust for time-varying covariates (age, congestive heart failure, hypertension, diuretic use, renal function, alcohol intake and dietary factors).

RESULTS

There was a graded relation between weight loss and achieving normouricaemia (P-value for trend<0.001). Compared with no weight change (-0.9 to 0.9 kg), the multivariate odds ratios of achieving normouricaemia for a weight loss of 1-4.9, 5-9.9 and ≥10 kg were 1.43 (95% CI: 1.33, 1.54), 2.17 (1.95, 2.40) and 3.90 (3.31, 4.61), respectively. The corresponding serum urate level changes were -7, -19 and -37 μmol/l (-0.12, -0.31 and -0.62 mg/dl). Similar levels of associations persisted among subgroups stratified by demographics, presence of gout, hypertension, diuretic use, renal insufficiency, alcohol intake, trial group assignment and adiposity categories (all P-values for trend<0.001).

CONCLUSIONS

Weight reduction could help achieve a widely accepted therapeutic urate target level (≤360 μmol/l) among men with a high cardiovascular risk profile. Although the urate-lowering effect appeared weaker than that of urate-lowering drugs, other associated health benefits would make weight reduction important, particularly in this population.

Is high serum uric acid a risk marker or a target for treatment? Examination of its independent effect in a large cohort with low cardiovascular risk

BACKGROUND

Cohort studies evaluating increased uric acid level as a cardiovascular disease (CVD) risk factor have shown variable results; studies are particularly lacking in lower risk populations.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

484,568 adults participating in a medical screening program in Taiwan since 1994 were followed up for a median of 8.5 years. Two subgroups were constructed: the first (n = 246,697; 51%) excluded participants with either overt CVD or overt CVD risk factors (including hypertension, diabetes, obesity, and hypertriglyceridemia) and the second (n = 157,238; 32%) further excluded individuals with early-stage CVD risk factors (including prehypertension, prediabetes, overweight, and borderline hypertriglyceridemia).

PREDICTOR

Serum uric acid.

OUTCOMES & MEASUREMENTS

All-cause and CVD mortality risk assessed using Cox proportional hazards models for categorical and continuous serum uric acid levels. As applicable, models adjusted for 14 variables. Population-attributable fraction was applied to compare contributions to mortality between high uric acid level and other CVD risk factors.

RESULTS

In the total cohort, mean age was 41.4 +/- 14.0 years and 26.2% had serum uric acid levels >or=7 mg/dL. Through 2007, there were 16,246 deaths (3.4% of all participants), with 35.2% of deaths occurring in individuals with hyperuricemia. Adjusted HRs associated with serum uric acid levels >or=7 mg/dL for all-cause and CVD mortality were 1.10 (95% CI, 1.04-1.17) and 1.38 (95% CI, 1.20-1.58), respectively. In individuals with hyperuricemia, 64.3% had overt CVD risk factors and 82.5% had either overt or early-stage CVD risk factors. Individuals with serum uric acid levels >or=8 mg/dL without overt CVD risk factors constituted 13.5% of the total study population with hyperuricemia; in analyses excluding those with overt CVD risk factors, serum uric acid level >or=8 mg/dL was significantly associated with all-cause and CVD mortality, with HRs of 1.37 (95% CI, 1.18-1.60) and 2.30 (95% CI, 1.51-3.49), respectively. In the subgroup of those with serum uric acid levels >or=8 mg/dL but who lacked both overt and early-stage CVD risk factors, the HRs for all-cause and CVD mortality were also significant and were 1.39 (95% CI, 1.08-1.78) and 2.38 (95% CI, 1.24-4.54), respectively. HRs for individuals with the same risk profiles but with serum uric acid of 7.0-7.9 mg/dL were not significant. In all groups, inclusion of proteinuria and glomerular filtration rate in models substantially attenuated the association between uric acid level and outcomes. High uric acid levels contributed a relatively insignificant portion to mortality (1.2%) and CVD deaths (4.5%) in this population.

LIMITATIONS

A single measurement of uric acid was used.

CONCLUSION

Increased serum uric acid level is a minor, but significant, risk factor for all-cause and CVD mortality. However, except for a small proportion (13.5%), increased serum uric acid level is more a risk marker than a target for treatment and is not an independent risk. Determining appropriate groups to target in clinical trials for uric acid-lowering therapy is critical.

Epidemiology of gout in women: Fifty-two-year followup of a prospective cohort

OBJECTIVE

Despite the recent doubling of the incidence of gout among women and its substantial prevalence particularly in the aging female population, the risk factors for gout among women remain unknown. We undertook this study to evaluate purported risk factors for incident gout among women and to compare them with those among men.

METHODS

Using prospective data from the Framingham Heart Study, we examined over a 52-year period (1950-2002) the relationship between purported risk factors and the incidence of gout in 2,476 women and 1,951 men.

RESULTS

We documented 304 incident cases of gout, 104 of them among women. The incidence rates of gout for women per 1,000 person-years according to serum uric acid levels of <5.0, 5.0-5.9, 6.0-6.9, 7.0-7.9, and > or = 8.0 mg/dl were 0.8, 2.5, 4.2, 13.1, and 27.3, respectively (P for trend < 0.0001). The magnitude of this association was lower than that among men (P for interaction = 0.0002). Multivariate relative risks conferred by increasing age (per 5 years), obesity (body mass index > or = 30 kg/m(2)), alcohol intake (> or = 7 ounces of pure alcohol/week), hypertension, and diuretic use were 1.24, 2.74, 3.10, 1.82, and 2.39, respectively (all P < 0.05), for women.

CONCLUSION

These prospective data with long-term followup provide evidence that higher levels of serum uric acid increase the risk of gout in a graded manner among women, but the rate of increase is lower than that among men. Increasing age, obesity, alcohol consumption, hypertension, and diuretic use were associated with the risk of incident gout among women.

Inflammation, oxidative stress and lipids: the risk triad for atherosclerosis in gout

For many years, the relationship between cardiovascular disease risk and gout, though strong and consistent, was suspected of being coincidental rather than causative. In recent years, compelling epidemiological and clinical data have increasingly favoured an aetiological connection. However, that connection is notably complex, involving a multifaceted model that includes interactions between inflammatory processes, oxidative stress and potential genetic influences, as well as cardiovascular and renal components that remain only partly explained. Urate appears to be able to activate the immune response, and in that context has a mediating role in the inflammatory process via the inflammasome. This interaction of urate and inflammation is central to the inflammatory cascade associated with gout flares. In the arena of oxidative stress, urate has both antioxidant and pro-oxidant properties, and while potentially beneficial in scavenging free radicals, it can also impair endothelial function and thereby give rise to atherosclerotic risk. Human and animal studies have revealed associations between hyperuricaemia and a host of atherosclerotic risk factors, whereas a reduction in urate levels is frequently associated with improvement or even resolution of such risk factors. The degree to which reduction of serum urate can reliably improve cardiovascular risk remains uncertain. It is hoped that the introduction of newer urate-lowering agents may help to clarify this picture and improve treatment options for both gout and atherosclerosis.

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.

Changes in waist circumference and body mass index in relation to changes in serum uric acid in Japanese individuals

OBJECTIVE

Studies have shown that obesity is associated with an increase in serum uric acid; and few data are available on the relationship between changes in measures of obesity and changes in uric acid concentrations. We investigated the relationship among percentage changes in waist circumference (%dWC), body mass index (%dBMI), and serum uric acid (%dUA).

METHODS

The data of 3153 individuals [1968 men, 1185 women (536 premenopausal, 649 postmenopausal)] who underwent general health screening over a 2-year period and were not taking antihyperuricemic medication were analyzed.

RESULTS

Stepwise multiple regression analysis showed that %dBMI was associated positively with %dUA in postmenopausal women and men, and the association retained statistical significance after adjustment for changes in blood pressure and in renal function. Association between %dBMI and %dUA was not significant in premenopausal women. In men, %dWC was a predicting factor for %dUA, although it did not remain significant when %dBMI was used as a covariate in the statistical model. Multivariate logistic regression analysis showed that the odds ratio of the association between the lowest %dBMI quartile (%dBMI < -1.86) and the lowest %dUA quartile (%dUA < -7.41) was 2.04 (95% CI 1.35-3.07) in postmenopausal women and 1.46 (95% CI 1.14-1.86) in men.

CONCLUSION

Weight loss may represent an effective nonmedical strategy for reducing serum UA levels, especially in postmenopausal women and men.

Sex and age interaction with genetic association of atherogenic uric acid concentrations

BACKGROUND

High serum uric acid levels are associated with gout, atherosclerosis and cardiovascular disease. Three genes (SLC2A9, ABCG2, and SLC17A3) were reported to be involved in the regulation of uric acid levels.

RESEARCH

DESIGN AND METHODS

SNPs rs2231142 (ABCG2) and rs1165205 (SLC17A3) were genotyped in three cohorts (n=4492) and combined with previously genotyped SNPs within SLC2A9 (rs6855911, rs7442295, rs6449213, rs12510549).

RESULTS

Each copy of the minor allele decreased uric acid levels by 0.30-0.38 mg/dL for SLC2A9 (p values: 10(-20)-10(-36)) and increased levels by 0.34 mg/dL for ABCG2 (p=1.1x10(-16)). SLC17A3 influenced uric acid levels only modestly. Together the SNPs showed graded associations with uric acid levels of 0.111 mg/dL per risk allele (p=3.8x10(-42)). In addition, we observed a sex-specific interaction of age with the association of SLC2A9 SNPs with uric acid levels, where increasing age strengthened the association of SNPs in women and decreased the association in men.

CONCLUSIONS

Genetic variants within SLC2A9,ABCG2 and SLC17A3 show highly significant associations with uric acid levels, and for SNPs within SLC2A9 this association is strongly modified by age and sex.

Gout in young migrant Filipino women in Israel: a changing epidemiology. Case reports and review of the literature

Gout is rare among young women. The prevalence of gout is increasing in the western world and the Far East, probably owing to life style changes. The association between hyperuricemia and gout, the metabolic syndrome and atherosclerosis is stronger in women. 40 years ago, the increased prevalence of hyperuricemia and gout in Filipino men living in the United States was described. Recently, Filipino men and women living in the western world were found to have increased risk of the metabolic syndrome and atherosclerosis. We describe two unusual cases of gout in premenopausal Filipino women living in Israel, both of which suffered from hypertension. We also describe the current knowledge about gout in women, in general, and in migrant Asian women, in particular, with an emphasis on its relations to the metabolic syndrome and atherosclerosis. The occurrence of gout in relatively young migrant Filipino women might signal a change in the epidemiology of this disease, and might signal that these women are more prone to develop the metabolic syndrome and its complications.

Menopause, postmenopausal hormone use and risk of incident gout

OBJECTIVE

To prospectively study the relation between menopause, postmenopausal hormone use and risk of gout, since female sex hormones have been postulated to decrease gout risk among women.

METHODS

In the Nurses' Health Study, the association between menopause, age at menopause, postmenopausal hormone use and risk of self-reported physician-diagnosed incident gout among 92 535 women without gout at baseline was examined. Multivariate proportional hazards regression analysis was used to adjust for other risk factors for gout such as age, body mass index, diuretic use, hypertension, alcohol intake and dietary factors.

RESULTS

During 16 years of follow-up (1 240 231 person-years), 1703 incident gout cases were recorded. The incidence rate of gout increased from 0.6 per 1000 person-years in women <45 years of age to 2.5 in women > or =75 years of age (p for trend <0.001). Compared with premenopausal women, postmenopausal women had a higher risk of incident gout (multivariate-adjusted relative risk (RR)=1.26; 95% confidence interval (CI) 1.03 to 1.55). Among women with a natural menopause, women with age at menopause <45 years had a RR of 1.62 (95% CI 1.12 to 2.33) of gout compared with women with age at menopause 50-54 years. Postmenopausal hormone users had a reduced risk of gout (RR=0.82; 95% CI 0.70 to 0.96).

CONCLUSION

These prospective findings indicate that menopause increases the risk of gout, whereas postmenopausal hormone therapy modestly reduces gout risk.

Serum urate, menopause, and postmenopausal hormone use: from eminence to evidence-based medicine

The relationship between serum urate, menopause, and aging has not been clearly defined by scientific evidence. In the present issue of Arthritis Research and Therapy, Hak and Choi present a cross-sectional analysis to clarify the effect of menopause and hormone replacement therapy on serum urate in women within the Third National Health and Nutritional Examination Survey. Menopause increased serum urate and hormone replacement therapy significantly decreased serum urate, although the overall level of change was small. The implications of these urate changes on gout and cardiovascular disease outcomes require further study.