Food Sources of Protein and Risk of Incident Gout in the Singapore Chinese Health Study

Effects of Dietary Fiber Supplementation on Modulating Uremic Toxins and Inflammation in Chronic Kidney Disease Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Emerging evidence supports the beneficial effects of dietary fiber supplementation in alleviating gut dysbiosis, which leads to a reduction in uremic toxins and inflammatory markers in chronic kidney disease (CKD) patients. However, current evidence-based renal nutrition guidelines do not provide recommendations regarding dietary fiber intake. We performed a systematic review and meta-analysis to investigate and highlight the effects of dietary fiber supplementation on modulating uremic toxins and inflammatory markers in individuals with CKD, with or without dialysis. The eligible randomized controlled trials (RCTs) were identified from PubMed, Scopus, and Cochrane Central Register of Controlled trials until 27 November 2024. The results were synthesized using a random-effects model and presented as standardized mean differences (SMDs) with a 95% confidence interval (CI). A total of 21 studies with 700 patients were included. When compared with the control group, dietary fiber supplementation ranging from 6 to 50 g/day, for typically more than 4 weeks, could significantly reduce the levels of serum uremic toxins, including p-cresyl sulfate, indoxyl sulfate, and blood urea nitrogen (SMD -0.22, -0.34, -0.25, respectively, with p-values < 0.05), as well as biomarkers of inflammation, including interleukin-6 and tumor necrosis factor alpha (SMD -0.44, -0.34, respectively, with p-values < 0.05). These beneficial effects were consistent across different types of fibers and CKD status (with or without dialysis). However, no significant reduction in serum trimethylamine N-oxide, uric acid, and high-sensitivity C-reactive protein levels was observed with dietary fiber intervention. This study would pave the way for prioritizing dietary quality, particularly a fiber-rich diet, beyond the traditional focus on the quantities of protein, energy, and electrolyte restrictions among individuals with CKD.

The cross-sectional and longitudinal associations between fruit intake and cognitive performance: the Chinese Healthy Dance Study

OBJECTIVE

To analyse the association between fruit consumption and cognitive performance in middle-aged and older adults in China.

METHODS

Participants were drawn from the Chinese Square Dance Cohort. The cross-sectional dataset included 4316 individuals, with their first visit from August 2020 to August 2023. The longitudinal dataset included 1465 participants, with their first visit from August 2020 to December 2021 and follow-up visits from August 2022 to December 2023. Fruit consumption was assessed using a food frequency questionnaire. Standardised neuropsychological assessments were used to measure composite z-scores of cognitive performance, and prevalent and incident mild cognitive impairment.

RESULTS

In the cross-sectional analysis, higher quartiles of citrus fruit, drupe, berry, and tropical fruit consumption were associated with higher composite z-scores for cognitive performance and lower odds of prevalent mild cognitive impairment. In the longitudinal analysis, there was a positive association between higher quartiles of citrus fruit intake and the annual rate of change in the composite z-scores for cognitive performance; standardised regression coefficient (95 % confidence interval) for the highest compared with the lowest quartile was 0.05 (0.02-0.08). Moreover, an association between higher quartiles of citrus fruit intake and a lower risk of incident mild cognitive impairment was detected; in the comparison of the highest with the lowest quartile, the risk ratio (95 % confidence interval) was 0.56 (0.36-0.88).

CONCLUSIONS

The relationship between fruit consumption and cognition varies across the different categories of fruit. Cognitive benefits of citrus fruit consumption were found for middle-aged and older adults. Ascertaining this association might enhance comprehensive dietary recommendations for fruit consumption.

Effects of dietary factors on hyperuricaemia and gout: a systematic review and meta-analysis of observational studies

This study aimed to gather the best evidence on the relationship between dietary factors and hyperuricaemia and gout. We searched databases including PubMed, Embase, Cochrane, and Web of Science from database creation to July 2023. Meta-analysis showed that consumption of alcohol (OR: 1.41, 95% CI: 1.29-1.55; 1.60, 95% CI: 1.33-1.93, respectively), red meat (OR:1.27, 95% CI: 1.18-1.37; 1.32, 95% CI: 1.18-1.47, respectively), fructose (OR: 1.29, 95% CI: 1.21-1.38; 1.65, 95% CI: 1.36-2.01, respectively) and seafoods (OR: 1.40, 95% CI: 1.20-1.64; 1.29, 95% CI: 1.00-1.67, respectively) were positively associated with the risk of hyperuricaemia and gout, while vegetables (OR: 0.78, 95% CI: 0.71-0.85; 0.96,95% CI 0.74-1.24, respectively) were inversely associated. Dairy products (OR: 0.69, 95% CI: 0.61-0.78) and nuts (OR: 0.75, 95% CI: 0.60-0.93) were also inversely associated with the risk of hyperuricaemia. Soy products (OR: 0.86, 95% CI: 0.75-0.98) and coffee (OR: 0.56, 95% CI: 0.39-0.81) were negatively associated with the risk of gout.

The association between Chinese adapted MIND diet and cognitive function in Chinese middle-aged and older adults: results from the Chinese Square Dance Cohort

PURPOSE

This study aimed to assess the relationship between Chinese adapted MIND diet and cognitive functioning and performance in different cognitive domains across a cross-section of Chinese middle-aged and older adults.

METHODS

This cross-sectional study used baseline data from the Lifestyle and Healthy Ageing in Chinese Square Dancers study. Chinese adapted MIND diet scores were calculated from a detailed retrospective semi-quantitative food frequency questionnaire assessment. By averaging the z-scores of Auditory Verbal Learning Test (AVLT), Verbal Fluency Test (VFT), Digital Symbol Substitution Test (DSST), and Trail Making Test-B (TMT-B), a comprehensive z-score is obtained to represent global cognition. Mild cognitive impairment (MCI) was diagnosed based on Petersen's criteria. Multiple linear regression models were used to analyze the relationship between Chinese adapted MIND diet scores and z-scores of cognitive functions, and multiple logistic regression models were used to assess the association between diet scores and MCI.

RESULTS

In this study, a total of 4335 participants were included, whose mean age was 63.61 years (SD = 5.15), 85.07% were female, and 13.33% (578/4335) of them had MCI. In the fully adjusted model, the group with the highest diet scores had the best cognitive function compared to the group with the lowest diet scores (P < 0.05), including global cognitive function (β = 0.10, 95% CI: 0.05, 0.15), AVLT (β = 0.12, 95% CI: 0.03, 0.20), VFT (β = 0.12, 95% CI: 0.03, 0.20), DSST (β = 0.07, 95% CI: 0.00, 0.14), and TMT-B (β =-0.10, 95% CI: -0.18, -0.01). In addition, compared to the lowest group, the highest diet scores group were associated with lower odd ratio of MCI (OR = 0.69, 95% CI: 0.51, 0.93).

CONCLUSIONS

Our findings support that higher adherence to Chinese adapted MIND diet is associated with better cognitive function and lower prevalence odds ratio for MCI in a Chinese middle-aged and older population.

Association of the serum levels of saturated fatty acids and mild cognitive impairment: a cross-sectional study

OBJECTIVES

To investigate the association of serum saturated fatty acids (SFAs) and prevalent mild cognitive impairment (MCI) among middle-aged and elderly Chinese.

METHODS

A total of 607 Chinese adults aged at least 45 years were included in the baseline survey of The Lifestyle and Healthy Aging of Chinese Square Dancer Study. Serum concentrations of individual SFAs including 6 even-chain SFAs (C14:0, C16:0, C18:0, C20:0, C22:0, and C24:0) and 4 odd-chain SFAs (C15:0, C17:0, C21:0, and C23:0), were quantified by Gas chromatography system with a mass spectrometer. According to Petersen's criteria, prevalent MCI was diagnosed by neurologists through uniformed neuropsychological tests, including trail-making test-part B (TMT-B), auditory verbal learning test (AVLT), digit symbol substitution test (DSST), and verbal fluency test (VFT).

RESULTS

The median age was 62 years with an interquartile range of 57.0 to 67.0 years, and 86 (14.17%) participants were living with MCI. Higher levels of either even-chain or odd-chain individual SFAs were associated with the higher odds of MCI, and their odds ratios (ORs) and 95% confidence intervals (95%CIs) were 2.054 (1.012 to 4.171) for C14:0, 2.246 (1.061 to 4.755) for C16:0, 2.789 (1.321 to 5.886) for C18:0, and 2.329 (1.136 to 4.778) for C15:0, and 2.761 (1.310 to 5.820) for C17:0, respectively.

CONCLUSIONS

The serum concentration of SFAs was positively related to the odds of MCI in middle-aged and elderly adults. Determining the link between SFAs profiles and MCI may inform a better understanding of the potential role of saturated fat intake on cognitive function.

Dietary Carbohydrates, Genetic Susceptibility, and Gout Risk: A Prospective Cohort Study in the UK

This study aimed to investigate the associations between carbohydrate intake and gout risk, along with interactions between genetic susceptibility and carbohydrates, and the mediating roles of biomarkers. We included 187,387 participants who were free of gout at baseline and completed at least one dietary assessment in the UK Biobank. Cox proportional hazard models were used to estimate the associations between carbohydrate intake and gout risk. Over a median follow-up of 11.69 years, 2548 incident cases of gout were recorded. Total carbohydrate intake was associated with a reduced gout risk (Q4 vs. Q1: HR 0.67, 95% CI 0.60-0.74), as were total sugars (0.89, 0.80-0.99), non-free sugars (0.70, 0.63-0.78), total starch (0.70, 0.63-0.78), refined grain starch (0.85, 0.76-0.95), wholegrain starch (0.73, 0.65-0.82), and fiber (0.72, 0.64-0.80), whereas free sugars (1.15, 1.04-1.28) were associated with an increased risk. Significant additive interactions were found between total carbohydrates and genetic risk, as well as between total starch and genetic risk. Serum urate was identified as a significant mediator in all associations between carbohydrate intake (total, different types, and sources) and gout risk. In conclusion, total carbohydrate and different types and sources of carbohydrate (excluding free sugars) intake were associated with a reduced risk of gout.

Relationship between dietary diversity and sleep quality: a Chinese community-based study

OBJECTIVES

The objective of this study was to examine the association between dietary diversity and sleep quality among Chinese middle-aged and older adults.

METHODS

The Lifestyle and Healthy Aging of Chinese Square Dancer Study is a prospective, community-based cohort study that enrolled participants aged 45 years and above from 2020 to 2021. Using the semiquantitative food frequency questionnaire to investigate the diets of study participants, and using the Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. Dietary diversity was assessed using two scoring methods covering ten food groups and 66 food items, respectively: the dietary diversity score (DDS) and the food variety score (FVS). The higher scores of DDS and FVS indicated greater dietary diversity and higher dietary quality. Logistic regression analysis explored the associations between these scores and sleep quality.

RESULTS

A total of 2409 individuals with completed information on PSQI and FFQ were included in this study, of whom 767 (31.8%) had poor sleep quality. Participants with higher DDS were associated with an 18% lower odds of poor sleep quality compared to those with low DDS (OR = 0.82, 95% CI, 0.68-0.98). Participants in the highest quartile of the FVS had a 32% lower odds of poor sleep quality than those in the lowest quartile (OR = 0.68, 95% CI, 0.52-0.89).

CONCLUSIONS

There was a positive correlation between higher FVS and DDS with better sleep quality. Therefore, ensuring a diverse diet may be beneficial for maintaining good sleep quality among middle-aged and older adults.

Association between combined exposure to ambient air pollutants, genetic risk, and incident gout risk: A prospective cohort study in the UK Biobank

BACKGROUND

Limited research has been conducted on the association between long-term exposure to air pollutants and the incidence of gout.

OBJECTIVES

This study aims to assess the individual and combined effects of prolonged exposure to five air pollutants (NO2, NOx, PM10, PMcoarse and PM2.52) on the incidence of gout among 458,884 initially gout-free participants enrolled in the UK Biobank.

METHODS

Employing a land use regression model, we utilized an estimation method to ascertain the annual concentrations of the five air pollutants. Subsequently, we devised a weighted air pollution score to facilitate a comprehensive evaluation of exposure. The Cox proportional hazards model was utilized to investigate the association between ambient air pollution and gout risk. Interaction and stratification analyses were conducted to evaluate age, sex, BMI, and genetic predisposition as potential effect modifiers in the air pollution-gout relationship. Furthermore, mediation analyses were conducted to explore the potential involvement of biomarkers in mediating the association between air pollution and gout.

RESULTS

Over a median follow-up time of 12.0 years, 7,927 cases of gout were diagnosed. Significant associations were observed between the risk of gout and a per IQR increase in NO2 (HR3: 1.05, 95 % CI4: 1.02-1.08, p = 0.003), NOx (HR: 1.04, 95 % CI: 1.01-1.06, p = 0.003), and PM2.5 (HR: 1.03, 95 % CI: 1.00-1.06, p = 0.030). Per IQR increase in the air pollution score was associated with an elevated risk of gout (p = 0.005). Stratified analysis revealed a significant correlation between the air pollution score and gout risk in participants ≥60 years (HR: 1.05, 95 % CI: 1.02-1.09, p = 0.005), but not in those <60 years (p = 0.793), indicating a significant interaction effect with age (p-interaction=0.009). Mediation analyses identified five serum biomarkers (SUA:15.87 %, VITD: 5.04 %, LDLD: 3.34 %, GGT: 1.90 %, AST: 1.56 %5) with potential mediation effects on this association.

CONCLUSIONS

Long-term exposure to air pollutants, particularly among the elderly population, is associated with an increased risk of gout. The underlying mechanisms of these associations may involve the participation of five serum biomarkers.

Association of aquatic food consumption, long-chain polyunsaturated n-3 fatty acid intake, and blood mercury levels with cognitive function in middle-aged and older adults

BACKGROUND & AIMS

Aquatic food is rich in nutrients which benefit the human brain and cognitive health; however, concerns about heavy metal accumulation in aquatic food remain. This study evaluated the associations between aquatic food consumption, long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs) intake, and blood mercury levels with cognition in middle-aged and older adults.

METHODS

This cross-sectional study used baseline data from the Lifestyle and Healthy Aging of Chinese Square Dancer Study. Aquatic food consumption and LC n-3 PUFAs intake were obtained from a food frequency questionnaire. Blood mercury levels were measured using inductively coupled plasma mass spectrometry. A composite z-score was developed to represent global cognition by averaging the z-scores for each cognitive domain. Participants with mild cognitive impairment (MCI) were diagnosed according to Petersen's criteria. Multivariate linear and logistic regression models were used to examine the association between the exposure factors and cognitive performance including cognitive scores and MCI.

RESULTS

Of 2621 middle-aged and older adults, the mean (SD) age was 63.71 (5.15) years, and 85.73% were females. Compared with the lowest quartile, those in the highest quartile for aquatic food consumption were associated with higher composite z-scores (β = 0.156, 95% CI: 0.088-0.225) and lower MCI odds (OR = 0.598, 95% CI: 0.425-0.841). A similar positive relationship between LC n-3 PUFAs intake and composite z-score and an inverse association between LC n-3 PUFAs intake and MCI were also observed. In addition, the participants in the highest quartile for blood mercury levels had higher composite z-scores than those in the lowest quartile.

CONCLUSIONS

In this cross-sectional study, higher aquatic food consumption, LC n-3 PUFAs intake, and blood mercury levels were related to better cognitive function. Further studies in Chinese populations are required to confirm these findings.

Dissecting the risk factors for hyperuricemia in vegetarians in Taiwan

BACKGROUND

Vegetarian diets have been shown to lower the risks of hyperuricemia and gout. Little is known about the risk factors of hyperuricemia in vegetarians.

METHODS

This community-based retrospective case-control study was conducted to establish prediction models for hyperuricemia. From September 5, 2005, to December 31, 2016, 7331 adult vegetarians were recruited at Taipei Tzu Chi Hospital. Hyperuricemia was defined as a serum uric acid concentration greater than 7 mg/dL.

RESULTS

There were 593 (8.1%) vegetarians with hyperuricemia and 6738 (91.9%) without hyperuricemia. We stepwise built up three models for predicting hyperuricemia in vegetarians. The full model (model 3) has the highest area under the receiver operating characteristic curve (AUROC, 85.52%). Additionally, the AUROC of model 3 is 77.97% and 84.85% in vegetarians with or without prior gout history, respectively. Moreover, male gender, hyperlipidemia, body mass index, and serum albumin are independent risk factors for hyperuricemia in vegetarians. In contrast, estimated glomerular filtration rate and proteinuria are independently associated with lower risks of hyperuricemia in vegetarians.

CONCLUSION

Our study revealed that risk factors for hyperuricemia, which includes clinical characteristics, account for more than 85% of discriminatory performance in Taiwanese vegetarians. This model may be helpful for monitoring and preventing hyperuricemia in the population.

The Management of Diabetes with Hyperuricemia: Can We Hit Two Birds with One Stone?

Serum urate (SU) is an independent predictor for the incidence of diabetes. In current diabetes treatment regimens, there is insufficient appreciation of the importance of hyperuricemia (HU) in disease control and prevention. To summarize the updated knowledge on the effects of SU on β-cell function, insulin resistance and chronic diabetic complications, as well as to evaluate the management of patients with both HU and diabetes, we searched the MEDLINE PubMed database, and included 285 journal articles. An inverted U-shaped relationship between fasting plasma glucose and SU levels was established in this review. Elevated SU levels may enhance the development of chronic diabetic complications, including macrovascular and microvascular dysfunction. Diet and exercise are essential parts of the lifestyle changes necessary for HU and diabetes management. Glucose- and urate-lowering drug selection and combination should be made with the principle of ameliorating, and at least not deteriorating, diabetes and HU. Medical artificial intelligence technology and monitoring systems can help to improve the effectiveness of long-term management of HU and diabetes through digital healthcare. This study comprehensively reviews and provides a scientific and reliable basis for and viewpoints on the clinical management of diabetes and HU.

Diet and metabolism are back: The oldest known Islamic medical manuscript bridges the gap from ancient to modern gout management

Gout is a chronic disease frequently associated with lifestyle; its prevalence is increasing in Western societies, as well as in the Middle East. Apart from its partial genetic features, diet accounts for 12% of the causality of the disease, while purine-rich foods contribute decisively to its development and evaluation. The influential Persian physician of the medieval ages, Abu Bakr Muhammad Ibn Zakariya al-Razi (or by his Latin name Rhazes; 860-925 AD), wrote a short book (20 chapters) entitled 'Treatise on gout'. Rhazes adopted the Hippocratic humoralism, and suggested that the disease results from metabolic excess in the peripheral blood, presenting sex dimorphism and age-dependence. His therapeutic guidelines include a diet prescribed by a physician, the use of laxatives and emetics, counter-balancing excess or deficiency of bile or phlegm and analgesics, bloodletting, foot and steam baths, as well as salves and poultices as preventive measures. He appends differential dietary restrictions/suggestions for phlegmatic or choleric patients: Small rations and intake of good quality foods low in purine by 20% for phlegmatic and 28% for choleric patients, as well as the restriction of foods high in purine by 27% for phlegmatic and 22% for the choleric patients. Finally, the acidic to alkaloid food intake ratio suggested is 2/5 for choleric and 3/7 for phlegmatic patients. His suggested foods and drugs are vitamin C and B-rich complexes, thereby inhibiting the accumulation of tophi.

The relationship between mushroom consumption and cognitive performance among middle-aged and older adults: a cross-sectional study

Objectives: Bioactive compounds in mushrooms may protect the brain from neurodegeneration by inhibiting the production of amyloid-β and playing an antioxidant role. This study aimed at examining the associations of mushroom consumption with cognitive function and mild cognitive impairment (MCI) among middle-aged and older adults in China. Design: A cross-sectional study. Setting and participants: This study was conducted in seven cities in China and included 2203 middle-aged and older adults. Methods: Data on mushroom consumption were collected using a semi-quantitative food frequency questionnaire. Cognitive function was evaluated by the Auditory Verbal Learning Test (AVLT), Verbal Fluency Test (VFT), Digit Symbol Substitution Test (DSST), and Trail Making Test-B (TMT-B). The composite z score was used to reflect global cognition. MCI was determined according to the Petersen criteria. Multiple linear regression and logistic regression were used to examine the relationship between mushroom consumption and cognitive performance. Results: This study included 2203 participants aged 55 years and above (mean age = 63.43 years). After controlling demographic characteristics, lifestyle factors, other dietary factors, and history of chronic disease, higher mushroom consumption was associated with better global cognition. Compared to the lowest quartile (Q1, 0-4.00 g day-1), the βs (95% confidence intervals, 95% CIs) were 0.10 (0.03, 0.18) for Q2 (4.01-10.42 g day-1), 0.13 (0.06, 0.20) for Q3 (10.43-20.84 g day-1), and 0.13 (0.06, 0.20) for Q4 (>20.84 g day-1). The higher mushroom consumption was positively related to better performance in DSST and TMT-B (P-values < 0.05). A 10 g day-1 increment in mushroom consumption was related to 12% lower odds of MCI (odds ratio = 0.88, 95% CI: 0.80-0.97). Conclusions: Higher mushroom consumption was positively related to better cognitive function and associated with lower odds of MCI. Further studies are needed to replicate our findings in other populations and determine the underlying mechanisms.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Environmental Triggers of Hyperuricemia and Gout

Gout is the most prevalent type of inflammatory arthritis worldwide and environmental factors contribute to hyperuricemia and risk for gout flare. Causes of hyperuricemia include increased purine consumption from meat, alcohol, and high fructose corn syrup as well as medications such as cyclosporine, low-dose aspirin, or diuretics. Triggers for gout flares include increased purine consumption and medication use such as urate lowering therapy and diuretics. Environmental exposures including lead exposure, particulate matter exposure, temperature fluctuations, and physiologic stress have been found to trigger flares. In the right clinical scenario, these factors should be considered when treating gout patients.

Soy consumption and serum uric acid levels: A systematic review and meta-analysis

Background

Soy consumption has health benefits, but the relationship between soy and uric acid remains uncertain. This meta-analysis and systematic review evaluated the effects of soy intake on plasma uric acid.

Methods

PubMed, Embase, CNKI, and the Cochrane Library were searched for studies evaluating the effects of soy, soy products, soy protein, and soy isoflavones on uric acid levels. The primary outcome was serum or plasma uric acid concentration. Study quality was evaluated by the Cochrane Collaboration and SYRCLE risk-of-bias tools.

Results

A total of 17 studies were included. Qualitative analysis of three human clinical studies of acute effects revealed that soy consumption increased serum uric acid concentration; however, soy-derived products, including tofu, bean curd cake, and dried bean curd sticks, had no significant effect on serum uric acid. A meta-analysis of five long-term human studies (10 data sets) revealed that soy protein and soy isoflavones had no significant effects on uric acid levels [weighted mean difference (WMD) = -2.11; 95% confidence interval (CI): -8.78, 4.55; p = 0.53]. However, most epidemiological data revealed that soy intake is inversely associated with uric acid levels. Meta-analysis of nine animal trials (29 data sets) revealed that soy protein and soy isoflavones significantly reduced serum uric acid concentrations (vs. controls; MD = -38.02; 95% CI: -50.60, -25.44; p < 0.001).

Conclusion

Soy and its products have different effects on serum uric acid. Soy products like tofu, bean curd cake, and dried bean curd sticks could be high-quality protein sources for individuals with hyperuricemia or gout. It can be beneficial to nutritionists and healthcare decision-makers reconsider their conceptions about the relationship between soy and uric acid levels according to the latest and further scientific study results.

Systematic review registration

[www.crd.york.ac.uk/PROSPERO], identifier [CRD42022331855].

Moving the Needle in Gout Management: The Role of Culture, Diet, Genetics, and Personalized Patient Care Practices

Gout is a metabolic disorder, and one of the most common inflammatory arthritic conditions, caused by elevated serum urate (SU). Gout is globally rising, partly due to global dietary changes and the growing older adult population. Gout was known to affect people of high socioeconomic status. Currently, gout disproportionately affects specific population subgroups that share distinct racial and ethnic backgrounds. While genetics may predict SU levels, nongenetic factors, including diet, cultural traditions, and social determinants of health (SDOH), need to be evaluated to optimize patient treatment outcomes. This approach would allow clinicians to assess whether certain cultural norms, or some SDOH, could be contributing to their patient's risk of developing gout or recurrent gout flares. A cultural assessment may inform the development of culturally tailored dietary recommendations for patients with gout. Causal and association studies investigating the interaction between diet, genetics, and gout, should be cautiously interpreted due to the lack of reproducibility in different racial groups. Optimal gout management could benefit from a multidisciplinary approach, involving pharmacists and nurses. While data on the effect of specific dietary recommendations on managing hyperuricemia and gout may be limited, counseling patients with gout on the role of a healthy diet to optimally control their gout flares and other comorbidities should be part of patient education. Future research investigating the role of a gene-diet interaction in the context of hyperuricemia and gout is needed. Optimal care for patients with gout needs to include a holistic assessment for gout and gout-related comorbidities. Additionally, addressing health beliefs and culture-specific lifestyle factors among patients with gout may reduce their risk of gout flare, improve adherence to urate-lowering therapy (ULT), and achieve health equity in gout management.

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

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

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

The Association between Dietary Purine Intake and Mortality: Evidence from the CHNS Cohort Study

Objectives: To investigate the association between dietary purine intake and mortality among Chinese adults. Methods: Based on data from the 2004−2015 China Health and Nutrition Survey (CHNS) and the corresponding edition of China Food Composition, the average purine intake per day (mg/day) from 2004 to 2011 was calculated, and the surveyed population was divided into five groups by quintiles. The outcome event and timepoint of concern were defined as death and time, respectively, as reported by family members, recorded until the 2015 survey. Cox proportional hazards regression was used to estimate the hazard ratios (HRs) with 95% confidence intervals (CIs) for death. The possibly nonlinear relationship between purine intake and mortality was examined with restricted cubic splines. Results: We included 17,755 subjects, and the average purine intake among them was 355.07 ± 145.32 mg/day. Purine intake was inversely associated with mortality (Ptrend < 0.001). Compared with the lowest quintiles of purine intake, the highest quintiles (HR = 0.60; 95% CI: 0.46, 0.77) showed a significant association with lower mortality. The negative association with mortality was mainly found in plant-derived purine (Ptrend = 0.001) and, weakly, in animal-derived purine (Ptrend = 0.052). In addition, a U-shaped relationship between purine intake and mortality was observed in males; however, there was no statistically significant dose−response relationship in females. Conclusion: Considering the low-purine-intake levels of the Chinese population, we observed a U-shaped relationship between purine intake and mortality in males, but purine intake may not relate to mortality in females. Future studies should investigate the causal relationship between purine intake and disease burden in China.

Hyperuricemia: Features of the Diet

The association of hyperuricemia (HU) with cardiovascular disease (CVD), diabetes, metabolic syndrome, and kidney disease has been demonstrated in numerous studies. НU is the main pathogenetic factor in the development of gout and is associated with an increase in overall and cardiovascular mortality. НU is included in the list of factors determining cardiovascular risk. According to epidemiological studies, there is a high prevalence of HU in the world and its increase in recent decades. A number of factors have been identified that contribute to the increased risk of НU. Non-modifiable factors include gender, age, genetic factors, and modifiable factors include diet and lifestyle. Nutritional unbalances, increased life expectancy, increased prevalence of obesity, and increased use of drugs (especially diuretics) are seen as contributing factors to the rise in НU. The review was carried out to summarize the available information on the effect of dietary habits, individual foods and nutrients on serum uric acid (SUA) levels and the risk of developing HU. The review presents the results of scientific studies demonstrating the relationship of НU with the consumption of foods rich in purines (offal, red meat, fish, seafood, legumes), alcohol consumption, drinks sweetened with fructose, coffee, dairy products, vegetables and fruits. Diet correction is an important and necessary step in the prevention and treatment of НU. The article reviews the basic principles of dietary management in HU and provides dietary recommendations for patients. For effective prevention and treatment of НU, a mandatory correction of the diet is required.

Diclofenac toxicity in susceptible bird species results from a combination of reduced glomerular filtration and plasma flow with subsequent renal tubular necrosis

Diclofenac caused the death of millions of vultures on the Asian subcontinent. Other non-steroidal anti-inflammatory drugs (NSAIDs) have since also been shown to be toxic to vultures with the exception of meloxicam. For this study, we evaluated the effect of diclofenac on renal uric acid transport and glomerulus filtration in an acute toxicity model. In a two-phase study with the same birds, healthy chickens (a validated model species) were treated intravenously with para-amino hippuric acid (PAH) and iohexol (IOH) in combination in phase 1. In phase 2, the same PAH and IOH combination was then combined with diclofenac (10 mg/kg). In both phases, blood and faeces were sequentially collected. In phase 1, the birds showed no signs of ill health. Moreover, PAH, IOH and uric acid clearance was rapid. In phase 2, two chickens showed early signs of hyperuricemia 8 hours after exposure and died approximately 24h later. Necropsy showed classic signs of renal damage and gout. Diclofenac had a rapid plasma half-life of elimination of less than 2 hours indicating that toxicity was likely due to an irreversible destruction of a physiological process. All the birds in phase 2 had decreased uric acid, PAH and IOH clearance in comparison to phase 1. The decrease in PAH clearance was variable between the birds (average of 71%) but was near 98% reduced in the two birds that died. It is concluded that diclofenac alters both renal perfusion and renal plasma flow, with death associated with tubular secretion being reduced to negligible functionality for a prolonged period. This would support previous in vitro findings of early cell death from ROS accumulation. However, further evaluation is needed to elucidate this final step.

Gout prevalence in the Hmong: a prime example of health disparity and the role of community-based genetic research

Individuals of distinct Asian backgrounds are commonly aggregated as Asian, which could mask the differences in the etiology and prevalence of health conditions in the different Asian subgroups. The Hmong are a growing Asian subgroup in the United States with a higher prevalence of gout and gout-related comorbidities than non-Hmong. Genetic explorations in the Hmong suggest a higher prevalence of genetic polymorphisms associated with an increased risk of hyperuricemia and gout. History of immigration, acculturation, lifestyle factors, including dietary and social behavioral patterns, and the use of traditional medicines in the Hmong community may also increase the risk of developing gout and lead to poor gout management outcomes. Engaging minorities such as the Hmong population in biomedical research is a needed step to reduce the burden of health disparities within their respective communities, increase diversity in genomic studies, and accelerate the adoption of precision medicine to clinical practice.

The Epidemiology and Genetics of Hyperuricemia and Gout across Major Racial Groups: A Literature Review and Population Genetics Secondary Database Analysis

Gout is an inflammatory condition caused by elevated serum urate (SU), a condition known as hyperuricemia (HU). Genetic variations, including single nucleotide polymorphisms (SNPs), can alter the function of urate transporters, leading to differential HU and gout prevalence across different populations. In the United States (U.S.), gout prevalence differentially affects certain racial groups. The objective of this proposed analysis is to compare the frequency of urate-related genetic risk alleles between Europeans (EUR) and the following major racial groups: Africans in Southwest U.S. (ASW), Han-Chinese (CHS), Japanese (JPT), and Mexican (MXL) from the 1000 Genomes Project. The Ensembl genome browser of the 1000 Genomes Project was used to conduct cross-population allele frequency comparisons of 11 SNPs across 11 genes, physiologically involved and significantly associated with SU levels and gout risk. Gene/SNP pairs included: ABCG2 (rs2231142), SLC2A9 (rs734553), SLC17A1 (rs1183201), SLC16A9 (rs1171614), GCKR (rs1260326), SLC22A11 (rs2078267), SLC22A12 (rs505802), INHBC (rs3741414), RREB1 (rs675209), PDZK1 (rs12129861), and NRXN2 (rs478607). Allele frequencies were compared to EUR using Chi-Square or Fisher’s Exact test, when appropriate. Bonferroni correction for multiple comparisons was used, with p < 0.0045 for statistical significance. Risk alleles were defined as the allele that is associated with baseline or higher HU and gout risks. The cumulative HU or gout risk allele index of the 11 SNPs was estimated for each population. The prevalence of HU and gout in U.S. and non-US populations was evaluated using published epidemiological data and literature review. Compared with EUR, the SNP frequencies of 7/11 in ASW, 9/11 in MXL, 9/11 JPT, and 11/11 CHS were significantly different. HU or gout risk allele indices were 5, 6, 9, and 11 in ASW, MXL, CHS, and JPT, respectively. Out of the 11 SNPs, the percentage of risk alleles in CHS and JPT was 100%. Compared to non-US populations, the prevalence of HU and gout appear to be higher in western world countries. Compared with EUR, CHS and JPT populations had the highest HU or gout risk allele frequencies, followed by MXL and ASW. These results suggest that individuals of Asian descent are at higher HU and gout risk, which may partly explain the nearly three-fold higher gout prevalence among Asians versus Caucasians in ambulatory care settings. Furthermore, gout remains a disease of developed countries with a marked global rising.

Shellfish consumption and health: A comprehensive review of human studies and recommendations for enhanced public policy

Shellfish, including various species of mollusks (e.g., clams, oysters, and mussels) and crustaceans (e.g., shrimp and crab), have been a cornerstone of healthy dietary recommendations. However, beyond providing basic nutrition needs, their health-promoting effects have been suggested to include inflammation reduction and prevention of various chronic non-communicable diseases. Currently, studies on the association between shellfish consumption and health outcomes have reported conflicting results. The present comprehensive review summarized the latest studies on shellfish consumption and synthesized the available evidence on the potential health benefits or risks of shellfish consumption. The findings demonstrated that shellfish consumption may increase the risk of hyperuricemia and gout but may not increase the risk of type 2 diabetes, cardiovascular diseases, and thyroid cancer. Adequate evidence is lacking on the association between shellfish consumption and the risk of colorectal cancer, pancreatic cancer, oral cancer, endometriosis, hip fracture, cognitive function, wheeze, eczema and food allergy. Raw shellfish consumption may cause gastroenteritis and other diseases infected by bacteria or viruses. This review thus provides consumers and other relevant stakeholders with the latest evidence-based information on the potential benefits and risks of shellfish consumption.

Systemic Investigation of Promoter-wide Methylome and Genome Variations in Gout

Current knowledge of gout centers on hyperuricemia. Relatively little is known regarding the pathogenesis of gouty inflammation. To investigate the epigenetic background of gouty inflammation independent of hyperuricemia and its relationship to genetics, 69 gout patients and 1455 non-gout controls were included. Promoter-wide methylation was profiled with EPIC array. Whole-genome sequencing data were included for genetic and methylation quantitative trait loci (meQTL) analyses and causal inference tests. Identified loci were subjected to co-methylation analysis and functional localization with DNase hypersensitivity and histone marks analysis. An expression database was queried to clarify biologic functions of identified loci. A transcription factor dataset was integrated to identify transcription factors coordinating respective expression. In total, seven CpG loci involved in interleukin-1β production survived genetic/meQTL analyses, or causal inference tests. None had a significant relationship with various metabolic traits. Additional analysis suggested gouty inflammation, instead of hyperuricemia, provides the link between these CpG sites and gout. Six (PGGT1B, INSIG1, ANGPTL2, JNK1, UBAP1, and RAPTOR) were novel genes in the field of gout. One (CNTN5) was previously associated with gouty inflammation. Transcription factor mapping identified several potential transcription factors implicated in the link between differential methylation, interleukin-1β production, and gouty inflammation. In conclusion, this study revealed several novel genes specific to gouty inflammation and provided enhanced insight into the biological basis of gouty inflammation.

Global epidemiology of gout: prevalence, incidence, treatment patterns and risk factors

Gout is the most common inflammatory arthritis and occurs when hyperuricaemia, sustained elevation of serum urate levels resulting in supersaturation of body tissues with urate, leads to the formation and deposition of monosodium urate crystals in and around the joints. Recent reports of the prevalence and incidence of gout vary widely according to the population studied and methods employed but range from a prevalence of <1% to 6.8% and an incidence of 0.58-2.89 per 1,000 person-years. Gout is more prevalent in men than in women, with increasing age, and in some ethnic groups. Despite rising prevalence and incidence, suboptimal management of gout continues in many countries. Typically, only a third to half of patients with gout receive urate-lowering therapy, which is a definitive, curative treatment, and fewer than a half of patients adhere to treatment. Many gout risk factors exist, including obesity, dietary factors and comorbid conditions. As well as a firmly established increased risk of cardiovascular disease and chronic kidney disease in those with gout, novel associations of gout with other comorbidities have been reported, including erectile dysfunction, atrial fibrillation, obstructive sleep apnoea, osteoporosis and venous thromboembolism. Discrete patterns of comorbidity clustering in individuals with gout have been described. Increasing prevalence and incidence of obesity and comorbidities are likely to contribute substantially to the rising burden of gout.

Dietary Interventions for Gout and Effect on Cardiovascular Risk Factors: A Systematic Review

Gout is one of the most prevalent inflammatory rheumatic disease. It is preceded by hyperuricemia and associated with an increased risk for cardiovascular disease, both related to unhealthy diets. The objective of this systematic review is to better define the most appropriate diet addressing both disease activity and traditional cardiovascular risk factors in hyperuricemic patients. We included clinical trials with patients diagnosed with hyperuricemia or gout, investigating the effect of dietary interventions on serum uric acid (SUA) levels, gout flares and—if available—cardiovascular risk factors. Eighteen articles were included, which were too heterogeneous to perform a meta-analysis. Overall, the risk of bias of the studies was moderate to high. We distinguished four groups of dietary interventions: Calorie restriction and fasting, purine-low diets, Mediterranean-style diets, and supplements. Overall, fasting resulted in an increase of SUA, whilst small (SUA change +0.3 to −2.9 mg/dL) but significant effects were found after low-calorie, purine-low, and Mediterranean-style diets. Studies investigating the effect on cardiovascular risk factors were limited and inconclusive. Since Mediterranean-style diets/DASH (Dietary Approach to Stop Hypertension) have shown to be effective for the reduction of cardiovascular risk factors in other at-risk populations, we recommend further investigation of such diets for the treatment of gout.

Cross-sectional association between non-soy legume consumption, serum uric acid and hyperuricemia: the PREDIMED-Plus study

PURPOSE

To assess the association between the consumption of non-soy legumes and different subtypes of non-soy legumes and serum uric acid (SUA) or hyperuricemia in elderly individuals with overweight or obesity and metabolic syndrome.

METHODS

A cross-sectional analysis was conducted in the framework of the PREDIMED-Plus study. We included 6329 participants with information on non-soy legume consumption and SUA levels. Non-soy legume consumption was estimated using a semi-quantitative food frequency questionnaire. Linear regression models and Cox regression models were used to assess the associations between tertiles of non-soy legume consumption, different subtypes of non-soy legume consumption and SUA levels or hyperuricemia prevalence, respectively.

RESULTS

Individuals in the highest tertile (T3) of total non-soy legume, lentil and pea consumption, had 0.14 mg/dL, 0.19 mg/dL and 0.12 mg/dL lower SUA levels, respectively, compared to those in the lowest tertile (T1), which was considered the reference one. Chickpea and dry bean consumption showed no association. In multivariable models, participants located in the top tertile of total non-soy legumes [prevalence ratio (PR): 0.89; 95% CI 0.82-0.97; p trend = 0.01, lentils (PR: 0.89; 95% CI 0.82-0.97; p trend = 0.01), dry beans (PR: 0.91; 95% C: 0.84-0.99; p trend = 0.03) and peas (PR: 0.89; 95% CI 0.82-0.97; p trend = 0.01)] presented a lower prevalence of hyperuricemia (vs. the bottom tertile). Chickpea consumption was not associated with hyperuricemia prevalence.

CONCLUSIONS

In this study of elderly subjects with metabolic syndrome, we observed that despite being a purine-rich food, non-soy legumes were inversely associated with SUA levels and hyperuricemia prevalence.

TRIAL REGISTRATION

ISRCTN89898870. Registration date: 24 July 2014.

Uric Acid and Plant-Based Nutrition

Plant-based diets (PBDs) are associated with decreased risk of morbidity and mortality associated with important noncommunicable chronic diseases. Similar to animal-based food sources (e.g., meat, fish, and animal visceral organs), some plant-based food sources (e.g., certain soy legume products, sea vegetables, and brassica vegetables) also contain a high purine load. Suboptimally designed PBDs might consequently be associated with increased uric acid levels and gout development. Here, we review the available data on this topic, with a great majority of studies showing reduced risk of hyperuricemia and gout with vegetarian (especially lacto-vegetarian) PBDs. Additionally, type of ingested purines, fiber, vitamin C, and certain lifestyle factors work in concordance to reduce uric acid generation in PBDs. Recent limited data show that even with an exclusive PBD, uric acid concentrations remain in the normal range in short- and long-term dieters. The reasonable consumption of plant foods with a higher purine content as a part of PBDs may therefore be safely tolerated in normouricemic individuals, but additional data is needed in hyperuricemic individuals, especially those with chronic kidney disease.

Gender-specific risk factors for gout: a systematic review of cohort studies

BACKGROUND

Though gout is more prevalent in men than women, it remains unclear whether gender influences risk factors for incident gout. We aimed to systematically review all cohort studies examining risk factors for the development of gout by gender.

METHODS

MEDLINE, EMBASE, CINAHL and the Cochrane Library were searched from inception to March 2019. Risk factors for gout examined were: age, ethnicity, consumption of alcohol, meat, seafood, dairy products, purine-rich vegetables, coffee and fructose, vitamin C intake, the Dietary Approaches to Stop Hypertension (DASH) diet, metabolic syndrome, BMI, waist and chest circumference, waist-to-hip ratio, weight change, diabetes mellitus, dyslipidaemias, renal disease, psoriasis, hypertension, diuretic use and anti-diabetic medication. Cohort studies were included if examining (at least) one of these risk factors for gout in either gender in the general population or primary care. Sample characteristics from included articles and their reported risk estimates were described using narrative synthesis.

RESULTS

Thirty-three articles were included, 20 (60.6%)directly compared risk factors by gender, 10 (30.3%) used men-only samples, 3 (9.1%) used women-only samples. Articles comparing risk across genders found similar increases in most risk factors. However, in men, metabolic syndrome (Hazard Ratio (95% CI) 1.37(1.20-1.58)) presented a risk of incident gout compared to none in women (> 50 years 1.15(0.85-1.54); ≤50 years 1.29(0.76-2.17)). Compared to men, women showed greater associated risk with higher consumption of fish and shellfish (HR (95% CI) Men: 1.02 (0.86-1.22); Women 1.36 (1.12-1.65)).

CONCLUSIONS

Risk factors for developing gout did not typically differ between genders and therefore similar preventative advice can be provided. Exceptions were metabolic syndrome in men and excessive seafood consumption in women, but these singular articles need further examination and in general more research into the risk factors for gout which includes women is required.

Vegetarian diet and risk of gout in two separate prospective cohort studies

BACKGROUNDS & AIMS

Plant-based diets may target multiple pathways in gout pathogenesis (uric acid reduction and anti-inflammation) while improving gout associated cardiometabolic comorbidities. We aim to prospectively examine the relationship between a vegetarian diet and gout, and to explore if this relationship is independent of hyperuricemia.

METHODS

We followed 4903 participants in the Tzu Chi Health Study (Cohort1, recruited in 2007-2009) and 9032 participants in the Tzu Chi Vegetarian Study (Cohort2, recruited in 2005) until end of 2014. Baseline serum uric acid was measured in Cohort1. Vegetarian status was assessed through a diet questionnaire that includes dietary habits and a food frequency questionnaire. Incidence of gout was ascertained by linkage to the National Health Insurance Database. Hazard Ratio of gout in vegetarians versus nonvegetarians was assessed by Cox regression, adjusted for age, sex, lifestyle and metabolic risk factors. Hyperuricemia was additionally adjusted in Cohort1.

RESULTS

In Cohort1, lacto-ovo vegetarians had the lowest uric acid concentration, followed by vegans, then nonvegetarians (men: 6.05, 6.19, 6.32 mg/dL, respectively; women: 4.92, 4.96, 5.11 mg/dL, respectively); 65 gout cases occurred in the 29,673 person-years of follow-up; vegetarians experienced a lower risk of gout (without adjustment for hyperuricemia: HR: 0.33; 95% CI: 0.14, 0.79; with adjustment for hyperuricemia: HR: 0.40; 95% CI: 0.17, 0.97). In Cohort2, 161 gout cases occurred in the 83,019 person-years follow-up, and vegetarians also experienced a lower risk of gout (HR: 0.61; 95% CI: 0.41, 0.88).

CONCLUSION

Taiwanese vegetarian diet is associated with lower risk of gout. This protective association may be independent of baseline hyperuricemia.

STUDY REGISTERED

URL: https://www.clinicaltrials.gov. Unique Identifier: NCT03470584.

The Daniel K. Inouye College of Pharmacy Scripts: Perspectives on the Epidemiology of Gout and Hyperuricemia

Gout is the most common inflammatory arthritic condition affecting more men than women. Hyperuricemia and the deposition of urate crystals into the joints are the hallmarks of gout. The prevalence of gout and hyperuricemia is rising in the United States and world-wide possibly due to the aging population, comorbidities, and other lifestyle factors. Gout and serum uric acid (SUA) levels are highly heritable, underscoring the role of genetics on disease risk and possibly the racial disparities in gout prevalence. However, high consumption of high fructose corn syrup, alcohol, select dietary lifestyles, and use of diuretics are associated with higher SUA levels and increased risk for developing gout. Adopting healthy diet and lifestyle modifications can lower SUA levels. Nonetheless, diet-based approaches for the management of gout should remain a secondary approach to urate lowering therapy.

Education and non-pharmacological approaches for gout

The objectives of this review are as follows: to highlight the gaps in patient and physician knowledge of gout and how this might impede optimal disease management; to provide recommended core knowledge points that should be conveyed to people with gout; and to review non-pharmacological interventions that can be used in gout management. MeSH terms were used to identify eligible studies examining patients' and health-care professionals' knowledge about gout and its management. A narrative review of non-pharmacological management of gout is provided. Many health-care professionals have significant gaps in their knowledge about gout that have the potential to impede optimal management. Likewise, people with gout and the general population lack knowledge about causes, consequences and treatment of this condition. Full explanation about gout, including the potential benefits of urate-lowering treatment (ULT), motivates people with gout to want to start such treatment, and there is evidence, albeit limited, that educational interventions can improve uptake and adherence to ULT. Additionally, several non-pharmacological approaches, such as rest and topical ice application for acute attacks, avoidance of risk factors that can trigger acute attacks, and dietary interventions that may reduce gout attack frequency (e.g. cherry or cherry juice extract, skimmed milk powder or omega-3 fatty acid intake) or lower serum uric acid (e.g. vitamin C), can be used as adjuncts to ULT. There is a pressing need to educate health-care professionals, people with gout and society at large to remove the negative stereotypes associated with gout, which serve as barriers to optimal gout management, and to perceive gout as a significant medical condition. Moreover, there is a paucity of high-quality trial evidence on whether certain simple individual dietary and lifestyle factors can reduce the risk of recurrent gout attacks, and further studies are required in this field.

The Dietary Fructose:Vitamin C Intake Ratio Is Associated with Hyperuricemia in African-American Adults

Background

A high fructose intake has been shown to be associated with increased serum urate concentration, whereas ascorbate (vitamin C) may lower serum urate by competing with urate for renal reabsorption.

Objective

We assessed the combined association, as the fructose:vitamin C intake ratio, and the separate associations of dietary fructose and vitamin C intakes on prevalent hyperuricemia.

Methods

We conducted cross-sectional analyses of dietary intakes of fructose and vitamin C and serum urate concentrations among Jackson Heart Study participants, a cohort of African Americans in Jackson, Mississippi, aged 21-91 y. In the analytic sample (n = 4576), multivariable logistic regression was used to examine the separate associations of dietary intakes of fructose and vitamin C and the fructose:vitamin C intake ratio with prevalent hyperuricemia (serum urate ≥7 mg/dL), after adjusting for age, sex, smoking, waist circumference, systolic blood pressure, estimated glomerular filtration rate, diuretic medication use, vitamin C supplement use, total energy intake, alcohol consumption, and dietary intake of animal protein. Analyses for individual dietary factors (vitamin C, fructose) were adjusted for the other dietary factor.

Results

In the fully adjusted model, there were 17% greater odds of hyperuricemia associated with a doubling of the fructose:vitamin C intake ratio (OR: 1.17; 95% CI: 1.08, 1.28), 20% greater odds associated with a doubling of fructose intake (OR: 1.20; 95% CI: 1.08, 1.34), and 13% lower odds associated with a doubling of vitamin C intake (OR: 0.87; 95% CI: 0.78, 0.97). Dietary fructose and the fructose:vitamin C intake ratio were more strongly associated with hyperuricemia among men than women (P-interaction ≤ 0.04).

Conclusion

Dietary intakes of fructose and vitamin C are associated with prevalent hyperuricemia in a community-based population of African Americans.

Gout and risk of knee replacement for severe knee osteoarthritis in the Singapore Chinese Health Study

OBJECTIVE

While cross-sectional and retrospective case-control studies suggest that gout is associated with knee osteoarthritis (KOA), no prospective study has evaluated the risk of total knee replacement (TKR) for KOA in association with gout. We prospectively evaluated the association between gout and the risk of TKR due to severe KOA.

DESIGN

We used data from the Singapore Chinese Health Study (SCHS), a prospective cohort with 63,257 Chinese adults aged 45-74 years at recruitment (1993-1998). Self-report of physician-diagnosed gout was enquired at follow-up I interview (1999-2004) from 52,322 subjects. TKR cases for KOA after follow-up I were identified via linkage with nationwide hospital discharge database through 31 December 2011. Multivariable Cox proportional hazards regression model was applied with adjustment for potential risk factors of KOA.

RESULTS

Among 51,858 subjects (22,180 men and 29,678 women) included in this analysis, after average 9.7 follow-up years, there were 1,435 cases of TKR. Gout was associated with 39% higher risk of TKR in women [hazard ratio (HR) 1.39; 95% confidence interval (CI) 1.08-1.79] but not in men (HR 0.78; 95% CI 0.49-1.23). The positive gout-TKR association in women remained after excluding participants with self-reported history of arthritis (HR 1.57; 95% CI 1.04-2.37). This association was stronger in women who were lean (body mass index [BMI] < 23 kg/m²) (HR 2.17; 95% CI 1.30-3.64) compared to their heavier counterparts (P_interaction = 0.016).

CONCLUSION

Gout is associated with risk of severe KOA, especially in lean women, suggesting the crystal arthritis may play a role in the pathogenesis or progression of OA.

Tailoring of recommendations to reduce serious cutaneous adverse drug reactions: a pharmacogenomics approach

The Health Sciences Authority launched a pharmacogenetics initiative in 2008 to facilitate evaluation of pharmacogenetics associations pertinent for Chinese, Malays and Indians in Singapore. The aim was to reduce the incidence and unpredictability of serious adverse drug reactions, with a focus on serious skin adverse drug reactions. This paper describes the gathering of evidence and weighing of factors that led to different genotyping recommendations for HLA-B*15:02 with carbamazepine and HLA-B*58:01 with allopurinol, despite both having strong genetic associations. Translation of pharmacogenomics at a national level requires careful deliberation of the prevalence of at-risk allele, strength of genetic associations, positive predictive value, cost-effectiveness and availability of alternative therapies. Our experience provides a perspective on translating genomic discoveries in advancing drug safety.

Cigarette Smoking and the Risk of Incident Gout in a Prospective Cohort Study

OBJECTIVE

Cigarette smoking is shown to reduce serum urate. However, its impact on risk of gout is unknown. We prospectively examined the relationship between cigarette smoking and gout risk in this Asian cohort.

METHODS

We analyzed the data from the Singapore Chinese Health Study, a cohort of 63,257 Chinese ages 45-74 years at recruitment in 1993-1998. Information on cigarette smoking and other lifestyle factors was collected through in-person interviews at recruitment. This analysis included 53,213 participants who took part in either the first followup (1999-2004) and/or the second followup interviews (2006-2010). Cox proportional hazards models were used to assess the relationship between cigarette smoking and gout risk.

RESULTS

A total of 2,244 incident cases of physician-diagnosed gout were identified after a mean followup of 11.1 years. Among men, compared to never smokers, the risk of gout in current smokers was decreased by 27% (hazard ratio [HR] 0.73 [95% confidence interval (95% CI) 0.63-0.84]). This risk reduction was greater in lean male smokers (HR 0.69 [95% CI 0.57-0.83]) than overweight smokers (HR 0.87 [95% CI 0.67-1.13]) (P = 0.09 for interaction). This inverse association with smoking was rapidly attenuated to become null even in former smokers who had recently quit smoking. Conversely, there was no association between smoking and gout risk in women. In a companion cross-sectional study, current smokers had significantly lower levels of serum urate than former and never smokers, and this observation was present in men and not women.

CONCLUSION

Current smoking is associated with lower risk of gout in men in this Asian cohort.

Bidirectional Association between Diabetes and Gout: the Singapore Chinese Health Study

We aimed to prospectively investigate the bidirectional association between type 2 diabetes (T2D) and gout. We analyzed follow-up data from the Singapore Chinese Health Study, when self-reports of diagnosed diabetes and gout were enquired at follow-ups I and II. Individuals who participated in both follow-ups and were free of cardiovascular disease or cancer at follow-up I were included. For T2D to gout (analysis I), prevalent gout were further excluded (final n = 31,137). For gout to T2D (analysis II), prevalent diabetes were excluded (final n = 28,668). Cox regression models were used to estimate relative risks (RRs). In the analysis I, the RR of diabetes to incident gout (682 cases) was 0.77 (95% CI 0.60–0.97). In the analysis II, the RR of gout to incident diabetes (2223 cases) was 1.36 (1.12–1.63), but became insignificant after adjustment for hypertension and BMI (1.00; 0.83–1.21). The gout to diabetes association was modified by BMI (P_interaction = 0.04) and hypertension (P_interaction = 0.007), and it was marginally significant in adults with BMI<24 while significant among non-hypertensive participants, but not in their counterparts. In conclusion, our results suggest that diabetes is associated with a lower risk of incident gout, while gout is positively related to diabetes among normal weight and non-hypertensive adults.