Association between vitamin D insufficiency and elevated serum uric acid among middle-aged and elderly Chinese Han women

Association between 25 hydroxyvitamin D and serum uric acid level in the Chinese general population: a cross-sectional study

BACKGROUD

The relationship between serum uric acid (SUA) and 25-hydroxyvitamin D (25(OH)D) has been variably characterized in existing literature, with inconsistent results regarding its nature and implications in the Chinese population. This study aims to clarify this association, considering the potential impact of vitamin D levels on SUA.

METHODS

This cross-sectional study involved 7,086 individuals from the Second Affiliated Hospital of Zhejiang University School of Medicine, screened throughout 2020. We collected data on 25(OH)D, SUA, and other metabolic markers. Logistic regression models adjusted for confounding factors were utilized to analyze the relationships.

RESULTS

Our findings illustrate a statistically significant inverted U-shaped relationship between 25(OH)D and SUA. The identified threshold effect at 28.82 ng/ml is pivotal; with 25(OH)D levels below this point associated with an increased risk of hyperuricemia (odds ratio: 1.0146, p = 0.0148), and levels above it offering protective benefits (odds ratio: 0.9616, p = 0.0164).

CONCLUSIONS

Our findings confirm a nonlinear, inverted U-shaped correlation between 25(OH)D and SUA, emphasizing the importance of maintaining vitamin D levels within a specific range to effectively manage hyperuricemia. These results support the implementation of personalized vitamin D supplementation strategies to optimize metabolic health outcomes, highlighting the complex interplay between vitamin D status and uric acid levels.

Vitamin D Reduces the Activity of Adenosine Deaminase and Oxidative Stress in Patients with Type Two Diabetes Mellitus

SCOPE

Patients with Type 2 diabetes mellitus (T2DM) have lower levels of vitamin D. An elevation in uric acid (UA) contributes to T2DM via an increase in oxidative stress. Adenosine deaminase (ADA) is an enzyme of the purine degradation pathway. It is hypothesized that a reduction of ADA activity via vitamin D supplementation reduces UA and oxidative stress.

METHODS AND RESULTS

A total of 162 participants (81 with T2DM and 81 controls) are enrolled in a case-control study. A follow-up interventional study is performed on 30 patients with vitamin D deficiency. These patients receive 50 000 IU (international units) of vitamin D3 on a weekly basis for 12 weeks. This intervention is followed by the measurement of several markers. T2DM patients has higher ADA activity, UA, and lipid peroxidation but lower 25-hydroxy-vitamin D (25 (OH) vitamin D) and GSH/GSSG ratio (p < 0.05). Vitamin D supplementation results in a reduction of ADA activity and UA levels (p < 0.05) along with an increase in GSH/GSSG ratio (p < 0.05).

CONCLUSION

The results highlight the presence of an axis in T2DM patients between ADA, UA, and oxidative stress. Modulation of this axis can be achieved by clinically approved vitamin D supplementation protocols.

The Inverted U-Shaped Association between Serum Vitamin D and Serum Uric Acid Status in Children and Adolescents: A Large Cross-Sectional and Longitudinal Analysis

BACKGROUND

Serum vitamin D is associated with hyperuricemia. However, previous studies have been controversial, with limited focus on children and adolescents.

OBJECTIVE

This study aimed to examine the cross-sectional and longitudinal associations between serum vitamin D and serum uric acid (SUA) levels in children and adolescents.

METHODS

The cross-sectional survey comprised 4777 participants aged 6 to 18 years, while the longitudinal survey involved 1641 participants aged 6 to 12 years, all derived from an ongoing cohort study in Shenzhen, China. Restricted cubic splines were used to visualize the dose-response relationship between vitamin D and SUA and the risk of higher SUA status. Two-segment generalized linear models (GLM) and logistic models were used to assess the association between vitamin D and SUA and higher SUA status, respectively. The longitudinal analysis used GLM.

RESULTS

We observed an inverted U-shaped relationship between vitamin D and SUA (p-overall < 0.0001, p-nonlinear = 0.0002), as well as the risk of higher SUA status (p-overall = 0.0054, p-nonlinear = 0.0015), with the vitamin D inflection point at 24.31 and 21.29 ng/mL, respectively. A 10 ng/mL increment in 25(OH)D3 levels, when below 20.92 ng/mL, was associated with a 68% rise in the risk of higher SUA status (OR: 1.68, 95%CI: 1.07-2.66). Conversely, when 25(OH)D3 levels were above or equal to 20.92 ng/mL, a 10 ng/mL increment was associated with a 45% reduction risk of higher SUA status (OR: 0.55, 95%CI: 0.36-0.84). Longitudinal analysis indicated that the annual change of SUA was from -4.80 (β, 95%CI: -10.74, 1.13) to -9.00 (β, 95%CI: -15.03, -2.99) and then to -6.77 (β, 95%CI: -12.83, -0.71, p for trend = 0.0212) μmol/L when increasing the quartile of vitamin D3.

CONCLUSIONS

An inverse U-shaped relationship was observed between vitamin D and SUA as well as the risk of higher SUA status. Sufficient vitamin D levels appear to play a preventative role against the age-related increase in SUA. Ensuring adequate vitamin D levels may be beneficial in improving uric acid metabolism.

Relationship between serum uric acid levels and osteoporosis

Osteoporosis (OP) is a systemic bone disease in which bone density and quality decrease and bone fragility increases due to a variety of causes, making it prone to fractures. The development of OP is closely related to oxidative stress. Uric acid (UA) is the end product of purine metabolism in the human body. Extracellular UA has antioxidant properties and is thought to have a protective effect on bone metabolism. However, the process of UA degradation can lead to intracellular oxidative stress, which together with UA-induced inflammatory factors, leads to increased bone destruction. In addition, UA can inhibit vitamin D production, resulting in secondary hyperparathyroidism and further exacerbating UA-associated bone loss. This review summarizes the relationship between serum UA levels and bone mineral density, bone turnover markers, and so on, in the hope of providing new insights into the pathogenesis and treatment of OP.

Are serum uric acid levels predictors of cardiovascular risk? An update

PURPOSE OF REVIEW

The aim of this review was to update the evidence regarding the link between serum uric acid and cardiovascular risk, as well as the role of nutrition in the prevention and management of hyperuricaemia.

RECENT FINDINGS

The review focuses on recent epidemiological evidence concerning the role of elevated serum uric acid levels in cardiovascular risk prediction. The dietary prevention and management of hyperuricaemia is also discussed with an emphasis on the adoption of prudent dietary patterns.

SUMMARY

There is evidence supporting that elevated serum uric acid levels are positively associated with cardiovascular disease risk and might represent a useful additional marker for risk stratification. The association of serum uric acid with all-cause and cardiovascular mortality seems to be U-shaped, suggesting that both very low and very high serum uric acid levels might be detrimental for survival, the former being mediated by malnutrition. Apart from medication, the dietary management of hyperuricaemia should focus on the adoption of a prudent dietary pattern, such as the Mediterranean diet, which can both prevent gout and mitigate cardiometabolic risk.

Correlation between Vitamin D and Uric Acid in Menopausal Women

Background : Vitamin D deficiency and hyperuricemia are global health problems in post-menopausal women in which parathyroid hormone increases hyperuricemia incidence. Aim : This research purpose to  determine correlation between vitamin D and uric acid levels in postmenopausal women Methods: This research is an observational analytic study with a cross-sectional study design conducted at University of North Sumatra Hospital and Network Hospital in Medan for 12 months on 40 postmenopausal women who met inclusion and exclusion criteria. The data will be analyzed descriptively to determine variables frequency distribution. Previously, normality test of numerical data is carried out. If the data is normally distributed, Pearson correlation test will be carried out, and if the data is not normally distributed, then Spearman correlation test will be used. Results : Mean vitamin D of the sample was 23.11 ng/mL with a standard deviation 4.43 and median value 23.5 ng/mL. while the mean uric acid was 7.52 mg/dL with a standard deviation 0.92 and median value 7.45 mg/dL. There is an inverse relationship between uric acid levels and Vitamin D, as evidenced by Pearson test correlation coefficient of -0.541 with p value = 0.001. Conclusion : There is an inverse correlation between Vitamin D and uric acid levels.

Serum 25-hydroxyvitamin D might be negatively associated with hyperuricemia in U.S. adults: an analysis of the National Health and Nutrition Examination Survey 2007-2014

PURPOSE

The results of previous studies on the relationship between serum 25-hydroxyvitamin D [25(OH)D] and hyperuricemia are controversial. We hypothesized that serum 25(OH)D concentrations of U.S. adults would negatively correlate with the risk of hyperuricemia.

METHOD

Data came from the National Health and Nutrition Examination Survey 2007-2014 were used, after excluding those who met at least one of the exclusion criteria, a total of 9096 male individuals and 9500 female individuals aged 18 years or older were included. Binary logistic regression analysis and restricted cubic spline with fully adjusted confounding factors were applied to evaluate the association between serum 25(OH)D and hyperuricemia. We further performed stratified analysis and sensitivity analysis to minimize the influence of gender, metabolic syndrome, obesity and renal dysfunction on the above association.

RESULTS

We found a negative correlation between serum 25(OH)D and hyperuricemia. In the binary logistic regression analysis, compared with the highest serum 25(OH)D quartile [Q4: 25(OH)D > 77.10 nmol/L] group, the odds ratios (95% confidence intervals) in the lowest quartile [Q1: 25(OH)D ≤ 43.20 nmol/L] was 1.46 (1.22-1.75) in the fully adjusted model. Restricted cubic spline analysis showed L-shaped and non-linear relationships between 25(OH)D and hyperuricemia. In sensitivity analysis, after restricting to participants without significant renal dysfunction and obesity, the above association remained significant. After restricting to participants who were diagnosed as metabolic syndrome, above association remained significant in the fully adjusted model. In stratified analysis by gender, the association remained significant among males and females.

CONCLUSIONS

Serum 25(OH)D might be inversely associated with hyperuricemia in general U.S. adults. From our study, for people with unexplained hyperuricemia, screening for serum Vitamin D concentration might be necessary.

Hyperuricemia is associated with secondary hyperparathyroidism in patients with chronic kidney disease

PURPOSE

Hyperuricemia is common among patients with chronic kidney disease (CKD). In the general population, hyperuricemia is associated with secondary hyperparathyroidism (SHPT), in a mechanism that involves vitamin D metabolism. Data for patients with CKD, however, are scarce. We aimed to evaluate the relationship between hyperuricemia and mineral and bone metabolism, particularly hyperparathyroidism.

METHODS

This is a retrospective study that included 922 adult patients with stages 3, 4, or 5 CKD, not on dialysis. Clinical, demographic, and biochemical data were collected from charts and included uric acid, parathyroid hormone (PTH), 25(OH)-vitamin D, calcium, phosphate, renal function (estimated glomerular filtration rate-eGFR), and medications such as allopurinol, furosemide, and cholecalciferol. SHPT was defined as PTH > 65 pg/ml.

RESULTS

Our patients were mostly Caucasian women, with a mean age of 64 ± 16 years. SHPT and hyperuricemia were observed in 70% and 62.4% of patients, respectively. Patients with SHPT presented higher levels of uric acid (7.2 ± 1.8 vs. 6.6 ± 1.7 mg/dL, p = 0.0001) and a higher frequency of hyperuricemia (66% vs. 33%, p = 0.0001). Patients with hyperuricemia were mostly female, with lower eGFR, higher phosphate, and higher PTH. The risk of hypovitaminosis D was higher among patients with SHPT (69.7% vs. 53.1%, p = 0.0001). Hyperuricemia remained independently associated with hyperparathyroidism, (p = 0.033) even after adjustments for eGFR, calcium, phosphate, hypovitaminosis D, and use of allopurinol, calcitriol, furosemide, and cholecalciferol.

CONCLUSION

Hyperuricemia seems to be a contributing factor for SHPT in patients with CKD. The mechanisms behind this finding have yet to be elucidated.

The relationship between uric acid and total femur bone mineral density in hypertensive and non-hypertensive populations

OBJECTIVE

This study aimed to explore the association between uric acid (UA) and total femur bone mineral density (BMD) in hypertensive and non-hypertensive groups.

METHODS

We conducted a cross-sectional study of 13,108 participants in the NHANES database, including 4,679 hypertensive and 8,429 non-hypertensive subjects. A weighted multiple linear regression analysis was conducted to explore the association between UA and total femur BMD.

RESULTS

In the hypertensive group, the relationship between UA and total femur BMD was positive [β, 3.02 (95% CI, -0.44 to 6.48), p = 0.0962). In the non-hypertensive group, the association was significantly positive [β, 5.64 (95% CI, 2.06-9.22), p = 0.0038]. In gender-stratified analysis, UA was analyzed as a continuous variable and a categorical variable (quartile). The significantly positive association was present in both the hypertensive male group [β, 5.10 (95% CI, 0.98-9.21), p for trend = 0.0042] and non-hypertensive male group [β, 10.63 (95% CI, 6.32-14.94), p for trend = 0.0001]. A smooth curve fitting showed that in the hypertensive male group, the relationship between UA and total femur BMD was an inverted U-shaped curve. In the hypertensive female group, the relationship was basically negative. In the non-hypertensive population, the relationship between UA and total femur BMD was an inverted U curve in both men and women.

CONCLUSION

In the hypertensive male group, the association between UA and total femur BMD was an inverted U-shaped curve. As to women, the relationship was basically negative. In the non-hypertensive group, the association between UA and total femur BMD was an inverted U-shaped curve in different genders.

Prevalence of Hyperuricemia and the Relationship Between Serum Uric Acid and Hypertension in New Onset Diabetic Patients: A Cross-Sectional Indian Study

OBJECTIVE

Prevalence of hyperuricemia (HU) is increasing and it is associated with hypertension, metabolic syndrome, diabetes mellitus (DM), obesity, chronic kidney disease, gout and cardiovascular disease. Elevated level of serum uric acid (SUA) has been shown to be associated with hypertension and diabetes in many countries but there is lack of evidence from India. The aim of this study is to know the prevalence of HU and to know the relationship between SUA and hypertension in newly onset DM.

METHODS

This is a cross-sectional study from a tertiary center. A total of 305 (males: 212; females: 93) newly diagnosed diabetic patients were enrolled. All patients were categorized as normotensive (<140/90) and hypertensive (≥140/90) based on ADA criteria. Based on SUA level participants were grouped into 3 tertile (T1: <4.52; T2: 4.52-5.64; T3: >5.64 mg/dl).

RESULTS

The mean age, systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the patients were 46.76 ±0.61 years, 130.6±1.06 mmHg and 84.11±0.63 mmHg, respectively. The mean level of SUA was 5.14±0.073 mg/dl and level was significantly higher in males compared with females (P <0.000). Overall prevalence of HU and hypertension was 12.13% and 44.59%, respectively. There was an increase in the prevalence of hypertension across the SUA tertile. SBP and DBP significantly increased across the SUA tertile (P <0.014 and <0.001, respectively). A multiple logistic regression analysis revealed that SUA tertile was independently associated with presence of hypertension (P <0.01).

CONCLUSION

This first report on the population of the eastern part of India indicates a significant positive relationship between SUA and hypertension among the newly onset Indian diabetic patients. Therefore, routine measurement of SUA is recommended in newly onset hypertensive diabetic patients to prevent HU and its related complications.

Effect of androgen on bone metabolism in hyperuricemic rats

INTRODUCTION

This study aimed to investigate the effect of androgen on bone metabolism in hyperuricemic rats.

MATERIAL AND METHODS

Forty male Wistar rats were randomly divided into four groups: sham operation group, simple hyperuricemic group, hyperuricemic castration group, and simple castration group. A rat model of chronic hyperuricemia was established using potassium oxonate and ethambutol. Blood was sampled from the vena angularis at week 0, 4, 6, 8 and 12 after surgery to detect for uric acid, calcium, phosphorus and alkaline phosphatase, and investigate the effect of androgen on bone metabolism in hyperuricemic rats.

RESULTS

From the 4^th week, compared with the sham operation group, the differences in uric acid levels between the simple hyperuricemic group and hyperuricemia castration group were statistically significant (p < 0.05), suggesting the successful establishment of the model of hyperuricemia. At the 6^th week, uric acid levels decreased in the two hyperuricemic groups, and the difference from the sham operation group decreased (p = 0.05), showing that the modeling method had deteriorated. At the 8^th week, the differences in uric acid levels between the two castration groups and sham operation group were statistically significant (p < 0.05). At the 12^th week, the differences in serum levels of phosphorus between the simple hyperuricemic group and hyperuricemic castration group were statistically significant (p < 0.05).

CONCLUSIONS

Androgen can induce bone metabolism changes in rats with hyperuricemia.

Vitamin D pathway gene variation rs3740165 is associated with serological uric acid levels in healthy Chinese women

AIM

To investigate the relationship between gene polymorphisms involved in the vitamin D metabolic pathway and serum uric acid (UA) levels in Chinese women.

METHODS

Fifteen key genes within the vitamin D metabolic pathway were screened using 96 single nucleotide polymorphisms in a group of 1,206 (37.96 ± 13.08 years) unrelated healthy Chinese women (aged 20-85 years). Blood and urine tests were performed at the same time. The Wilcoxon Mann-Whitney test was used to compare groups aged ≤50 years and >50 years. The mean serum UA values were computed within each group of homozygous referent, heterozygous, and homozygous variant genotypes for each single nucleotide polymorphism.

RESULTS

The exclusion process left 1,169 participants (38.16 ± 13.13 years) for analysis. One single nucleotide polymorphism in the CUBN gene (rs3740165) was identified as being significantly associated with serum UA levels in the group aged over 50 years. The wild type (C/C) population had higher serum UA levels in this group (P<0.001). In women aged over 50 years, allele C was associated with a higher risk of hyperuricemia than allele T (odds ratio 2.752, 95% confidence interval 1.458-5.192; P = 0.002). There was also a higher risk of hyperuricemia in genotype TC + CC compared with genotype TT (odds ratio 3.326, 95% confidence interval 1.513-7.313; P = 0.003) in women over 50 years of age.

CONCLUSION

The results suggest that the CUBN gene contributes to variability in serum UA levels in healthy Chinese Han women over 50 years of age.

Calcitriol Treatment Attenuates Uric Acid-Induced Kidney Injury via Super Oxide Dismutase-1 (SOD-1) Upregulation and Fibrosis Reduction

Background

Hyperuricemia induces nephropathy through the mediation of oxidative stress, tubular injury, inflammation, and fibrosis. The high uric acid level is associated with the reduction of vitamin D levels. However, the reno-protective effects of this vitamin in hyperuricemia condition remain unknown. This study aimed to elucidate calcitriol treatment in a uric acid-induced hyperuricemia mice model.

Methods

: Uric acid (125 mg/kg body weight [BW]) was administered intraperitoneally for 7 (UA7) and 14 (UA14) days. Calcitriol (0.5 g/kg BW) was intraperitoneally injected for the following seven days, after 14 days of uric acid induction (UA14VD7 group). The control group received NaCl 0.9%, by the same route. Serum creatinine was measured using calorimetric method, and uric acid levels were assessed using enzymatic calorimetric assay. Tubular injury and fibrosis were assessed using PAS and Sirius red staining. RT-PCR and real-time reverse transcription PCR were carried out for the analyses of SOD-1, Collagen-1, and TGF-1 mRNA expression in the kidney. Immunostaining of super oxide dismutase type 1 (SOD-1) was performed to detect its expression in the kidney.

Results

Uric acid and creatinine levels markedly increased in UA14 groups, followed by an exacerbation of tubular injury. RT-PCR revealed the upregulation of Collagen-1 and TGF-1, along with the downregulation of SOD-1. Calcitriol treatment attenuated the injury with reducing uric acid and creatinine levels, as well as tubular injury. This was associated with lower Collagen-1 and TGF-1 mRNA expression compared to the UA7 and UA14 groups. SOD-1 was upregulated in epithelial cells in the UA14VD7 group.

Conclusion

Calcitriol treatment after uric acid induction may attenuate kidney injury through upregulation of SOD-1 and downregulation of Collagen-1 and TGF-1 gene expression.

The geriatric nutritional risk index mediated the relationship between serum uric acid and hypertension: a mediation analysis

Background

The elevated serum uric acid (SUA) is associated with an increased risk of hypertension and nutritional status. Malnutrition might modify the association of SUA with hypertension. Therefore, the aims of this study were to examine the mediation effect of malnutrition on the association of SUA with the risk of hypertension in Chinese population.

Methods

The study was based on the China Health and Nutrition Survey in 2009. Participants aged ≥ 60 years with complete analyzed data were eligible. The Geriatric Nutritional Risk Index (GNRI) was calculated by serum albumin (ALB) and BMI. Participants were identified as hypertension if systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg or receiving antihypertensive drug.

Results

There were 2371 participants included in the final analysis. In total, there was a significant mediation effect of the GNRI on the relationship between SUA level with hypertension (P < 0.001; OR: 1.096; and 95 % CI: 1.048–1.146). And the proportion mediated was 17.77 %. The results stratified by sex were consistent with those of total population. The significant mediation effects of the GNRI were found in the 60–69 years and 70–79 years groups (P = 0.002 and 0.032; OR: 1.099 and 1.075; and 95 % CI: 1.036–1.165 and 1.006–1.148, respectively) but not in the 80–99 years group (P = 0.303). The proportions mediated were16.22 % and 18.36 %, respectively.

Conclusions

The GNRI can mediate and account for approximately 17.77 % of the relationship between SUA level and the risk of hypertension. And this mediation effect was fully observed in both males and females, especially in the 60–79 years population.

Associations between Serum Vitamins and Serum Uric Acid in a Population of Shenyang, China

Previous studies have demonstrated that serum vitamins are associated with serum uric acid (SUA) level. However, no study has comprehensively investigated whether various serum vitamins are associated with SUA level in a general population. Thus, a cross-sectional study was designed to explore the associations between SUA level and serum vitamins. The data of this study for SUA levels were collected from participants aged ≥18 y. Serum vitamin and other baseline information, including age and body mass index, was determined. Moreover, associations between SUA level and serum vitamins were explored using analysis of covariance. Higher levels of SUA were significantly associated with a higher level of serum vitamins A, B9 and B5 (p<0.05). Higher level of SUA were associated with a lower level of serum vitamins C, and D2 (p<0.05). No significant associations were found between vitamins C, and D2 and SUA levels after adjustment. Study results suggested that serum vitamins A, B9 and B5 were positively associated, whereas serum vitamins C, and D2 were inversely associated with SUA levels.

Vitamin D supplementation is associated with serum uric acid concentration in patients with prediabetes and hyperuricemia

Aims

Vitamin D deficiency is associated with a number of noncommunicable conditions. We conducted a randomised controlled trial to determine the effect of vitamin D supplementation on serum uric acid concentration in patients with prediabetes, in whom hyperuricaemia is common.

Methods

Seventy-one volunteers (35–80 years), with impaired fasting glucose and/or impaired glucose tolerance were randomised to three groups, vitamin D₃, vitamin D₂ and control, and followed for 12 months.

Results

After 12 weeks, vitamin D supplementation was associated with a reduction in serum uric acid concentration in participants with baseline uric acid concentration > 6 mg/dL, but no significant change was observed in controls. We then assessed the dose–response relationship between vitamin D supplementation and the change in serum uric acid concentration and found that the change in serum total 25-hydroxyvitamin D did not correlate with the change in serum uric acid that occurred during vitamin D supplementation. The factors associated with larger reductions in serum uric acid were a higher baseline serum uric acid and a larger increase in serum 1,25-dihydroxyvitamin D.

Conclusions

Vitamin D supplementation lowers serum uric acid in prediabetic patients with hyperuricaemia, and supplementation might be considered to help alleviate hyperuricaemia in these patients.

Vitamin D Effect on Ultrasonography and Laboratory Indices and Biochemical Indicators in the Blood: an Interventional Study on 12 to 18-Year-Old Children with Fatty Liver

PURPOSE

The rising prevalence of childhood obesity in the past decades has caused non-alcoholic fatty liver disease (NAFLD) to become the most common cause of pediatric chronic liver disease worldwide. This study was aimed at determining the effect of vitamin D (Vit D) on ultrasonography and laboratory indices of NAFLD and some blood biochemical indicators in children.

METHODS

In this interventional study liver ultrasonography was performed in 200 children with overweight and obesity. A 108 had fatty liver among which 101 were randomly divided into two groups of study (n=51) and control (n=50). The study group was treated with Vit D, 50000 U once a week whereas the control group received placebo with the same dose and package, both for 12 weeks. At the end of the intervention lab tests and ultrasound study was performed once again to evaluate the response to treatment.

RESULTS

It was found out that Vit D supplementation improved the fatty liver grade in the study group. The mean changes in hemoglobin (Hb), uric acid, highdensity lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), insulin, albumin and alanine aminotransferase (ALT) was significantly higher in the study group compared to controls (p<0.05). After the intervention and means adjustment, a significant difference was obtained in HDL-C, insulin, LDL-C and homeostasis model assessment of insulin resistance (HOMA-IR) between the two groups.

CONCLUSION

Vit D supplementation in addition to improving the fatty liver grade in ultrasonography and increasing the blood Vit D level, increases the HDL and Hb level besides decreasing uric acid, LDL, HOMA-IR, insulin and ALT levels.

Serum uric acid and mortality thresholds among men and women in the Irish health system: A cohort study

BACKGROUND

Elevation of serum uric acid (SUA) is associated with increased mortality; however, controversy exists regarding the nature of the relationship and differences between men and women. We explored relationships of SUA levels with all-cause mortality in a large cohort of patients within the Irish health system.

METHODS

A retrospective cohort study of 26,525 participants was conducted using data from the National Kidney Disease Surveillance System. SUA was modelled in increments of 59.48 µmol/L (1 mg/dL), Cox's proportional hazards model estimated hazard ratios (HRs) and 95% Confidence Intervals (CI), median lifetimes were also computed separately for men and women. Mortality patterns were further explored using penalised splines.

RESULTS

There were 1,288 (4.9%) deaths over a median follow-up of 5.1 years. In men, the risk of mortality was greatest for the lowest (<238 µmol/L) and highest (>535 µmol/L) categories [HR 2.35 (1.65-3.14) and HR 2.52 (1.87-3.29) respectively]; the corresponding median lifetimes for men were reduced by 9.5 and 11.7 years respectively compared to the referent. In women, mortality risks were elevated for SUA >416 mol/L [HR 1.69 (1.13-2.47) and beyond; the corresponding median lifetime for women were reduced by 5.9 years compared to the referent. Spline analysis revealed a U-shaped association between SUA and mortality in men, while for women, the pattern of association was J-shaped.

CONCLUSION

Mortality patterns attributed to SUA differ between men and women. Optimal survival was associated with SUA concentrations of 304-454 µmol/L for men and < 409 µmol/L for women.

Serum Uric Acid Levels, but Not rs7442295 Polymorphism of SCL2A9 Gene, Predict Mortality in Clinically Stable Coronary Artery Disease

Serum uric acid (SUA) has been associated with cardiovascular disease, but up to now whether SUA is an independent cardiovascular risk factor or merely a disease-related epiphenomenon remains still controversial. within the framework of the Verona Heart Study, we prospectively followed 703 subjects with angiographically demonstrated and clinically stable coronary artery disease between May 1996 and March 2007. At baseline, SUA levels were measured in all the patients. Genotype data of SCL2A9 rs7442295 polymorphism, which has been associated with SUA by genome-wide association studies, were available for 686 subjects (97.6%). After a median follow-up of 57 months, 116 patients (16.5%) had died, 83 (11.8%) because of cardiovascular causes. Patients with hyperuricemia, defined by SUA levels above the 75th percentile (≥0.41 mmol/L), had an increased total and cardiovascular mortality rate than those with SUA below this threshold level (23.3% vs 14.1%, P = 0.048 and 19.4% vs 9.2%, P = 0.001, respectively, by Kaplan-Meier with Log-Rank test). These associations were confirmed by Cox regression after adjustment for sex, age, other predictors of mortality, coronary revascularization, and drug therapies at discharge (hazard ratio for total mortality 1.87 [1.05-3.34], P = 0.033; hazard ratio for cardiovascular mortality 2.09 [1.03-4.25], P = 0.041). Although associated with SUA levels, rs7442295 polymorphism did not predict total or cardiovascular mortality. our data support that SUA may be a prognostic cardiovascular biomarker, predicting total and cardiovascular mortality in the setting of secondary prevention of coronary artery disease. On the other hand, SCL2A9 gene polymorphism, notwithstanding a clear influence on SUA levels, was not associated with mortality.

Serum Urate Lowering Therapy Using Allopurinol Improves Serum 25 Hydroxy Vitamin D in Stage 3-5 CKD Patients: A Pilot Study

BACKGROUND

Recent studies have demonstrated negative associations of serum uric acid (SUA) with serum 25 hydroxy vitamin D (25 [OH] vit D) among CKD patients.

OBJECTIVE

The aim of the study was to look for the impact of hypouricemic therapy using allopurinol on serum level of 25 (OH) vit D in CKD patients.

CASES AND METHODS

Seventy-two CKD stage 3-5 patients were selected to this study. Patients with SUA above 7 mg/dL were allocated to hypouricemic therapy using allopurinol (group I). A control group of cases not suffering marked increase in SUA were included as control group (group II). All cases were followed up for 3 months. Serum Cr, SUA, ionized calcium (SiCa), phosphorus, 25 (OH) vitD, parathyroid hormone (PTH), and 24-h urine protein were estimated at entry and by the end of the study.

RESULTS

At least 20 cases completed the study in each group. Serum 25 (OH) vit D significantly increased in group I (26.4 [14.1] vs. 39.6 [14.8] at entry vs. at end of the study, p < 0.001). In addition, SUA, PTH, and urine protein significantly decreased (11 [1.6] vs. 3.95 [0.58] mg/dL, 267.5 [97.5] vs. 225.5 [153] ng/mL, and 2.7 [1.18] vs. 1.5 [1.08] gm/day, p < 0.001, = 0.043, and <0.001 respectively). SiCa and phosphorus significantly increased (4.4 [0.3] vs. 5.2 [0.5] mg/dL and 4.25 [0.72] vs. 4.9 [0.75] mg/dL, p < 0.001 and = 0.007, respectively).

CONCLUSION

This study supports a negative causal relationship between SUA and serum 25 (OH) vit D. Further studies are still needed to confirm this conclusion.

Association Between Vitamin D and Hyperuricemia Among Adults in the United States

Background: Serum uric acid can act as a risk factor for cardiovascular disease (CVD) and as antioxidant defense. Vitamin D deficiency can activate the parathyroid to induce the release of parathyroid hormone, which was thought to increase serum uric acid level, and low vitamin D status may also be associated with risk of CVD. No known studies have explored the association between serum 25(OH) D, vitamin D intake, and HU for the American population.

Methods: We extracted 15,723 US adults aged 20–85 years from the National Health and Nutrition Examination Survey (NHANES) in 2007–2014. All dietary intakes were evaluated through 24-h dietary recalls. Multivariable logistic regression analysis was performed to examine the associations after adjustment for confounders.

Results: Compared to the lowest quintile (Q1), for males, adjusted odds ratios (ORs) of HU in Q2 to Q4 of serum 25(OH) D levels were 0.78 (95% CI, 0.65–0.93), 0.97 (0.81–1.16), and 0.72 (0.60–0.88); ORs in Q2–Q5 of total vitamin D intake were 0.83 (0.69–0.98), 0.69 (0.58–0.83), 0.66 (0.55–0.79), and 0.59 (0.48–0.71), respectively. In females, OR was 0.80 (0.66–0.97) of serum 25(OH) D for Q3, and ORs in Q5 of total vitamin D intake were 0.80 (0.65–0.98).

Conclusions: Our findings indicated that the serum 25(OH) D intakes of dietary vitamin D, supplemental vitamin D, and total vitamin D were inversely associated with HU in males. In females, a lower risk of HU with higher serum 25(OH) D, dietary vitamin D, and total vitamin D intake was found, but with no association between supplemental vitamin D intake and the risk of HU.

Association Between Vitamin D and Uric Acid in Adults: A Systematic Review and Meta-Analysis

Association between vitamin D and uric acid is complex and might be bidirectional. Our study aimed to determine the bidirectional association between vitamin D and uric acid in adults. Using MEDLINE via PubMed and Scopus, we systematically searched for observational or interventional studies in adults, which assessed the association between serum vitamin D and serum uric acid, extracted the data, and conducted analysis by direct and network meta-analysis. The present review included 32 studies, of which 21 had vitamin D as outcome and 11 had uric acid as outcome. Meta-analysis showed a significant pooled beta coefficient of serum uric acid level on serum 25(OH)D level from 3 studies of 0.512 (95% confidence interval: 0.199, 0.825) and a significant pooled odds ratio between vitamin D deficiency and hyperuricemia of 1.496 (1.141, 1.963). The pooled mean difference of serum 25(OH)D between groups with hyperuricemia and normouricemia was non-significant at 0.138 (-0.430, 0.707) ng/ml, and the pooled mean difference of serum uric acid between categories of 25(OH)D were also non-significant at 0.072 (-0.153, 0.298) mg/dl between deficiency and normal, 0.038 (-0.216, 0.292) mg/dl between insufficiency and normal, and 0.034 (-0.216, 0.283) mg/dl between deficiency and insufficiency. In conclusion, increasing serum uric acid might be associated with increasing 25(OH)D level, while vitamin D deficiency is associated with hyperuricemia. These reverse relationships should be further evaluated in a longitudinal study.

Association between serum vitamin D and uric acid in the eastern Chinese population: a population-based cross-sectional study

BACKGROUND

Uric acid (UA) is the end product of purine metabolism, which is thought to be related to many human diseases, such as nephrolithiasis, gout, cardiovascular disease (CVD), type 2 diabetes mellitus, metabolic syndrome. However, the relationship between serum UA (SUA) and 25(OH) D is still unclear in the eastern Chinese population.

METHODS

We did a population-based observational investigation, which included 12,770 residents living in eastern China. Ultimately, data from 9220 subjects were analyzed. Serum 25(OH) D, SUA, fasting plasma glucose (FPG), fasting insulin, HbA1c and other metabolic parameters were tested. Waist circumference (WC), weight and height were also measured. Questionnaires were collected from these subjects for information on smoking and drinking status.

RESULTS

We enrolled 9220 Chinese adults, including 3681 males (age 55.57 ± 13.23 years) and 5539 females (age 54.31 ± 12.83 years). The levels of SUA were 352.07 ± 79.25 nmol/L and 269.29 ± 64.68 nmol/L in males and females, respectively. The proportion of adults with hyperuricemia (HUA) was 12.26% in the total population. Levels of SUA were positively associated with 25(OH) D, and the incidence of HUA increased 9.4% for every 10 nmol/L increase in 25(OH) D (P < 0.001).

CONCLUSIONS

SUA was positively associated with 25(OH) D in the eastern Chinese population. Higher levels of serum 25(OH) D may be a potential predictor of HUA.

Type 2 Diabetes Mellitus, Insulin Resistance, and Vitamin D

PURPOSE OF REVIEW

There is a growing, largely inconsistent, literature on the role of vitamin D in association with type 2 diabetes, insulin resistance/insulin secretion, glycemic indices, and complications of type 2 diabetes. Pathophysiologic, bystander, preventive, and treatment roles of vitamin D have all been proposed. In this focused review, we attempt to organize and clarify our current information in this area.

RECENT FINDINGS

Clinical study interpretation is difficult because of variability in dosage, dosage form, study duration, and populations studied, as well as recently reported normal human polymorphisms in vitamin D synthesis and catabolism, vitamin D-binding protein, and vitamin D receptors in addition to a host of potential epigenetic confounders. Low vitamin D status appears to be associated with type 2 diabetes and most other insulin resistance disorders reported to date. The extraskeletal benefits of supplementation/repletion in these disorders in our species, with a few highlighted exceptions, remain to be established. This focused review attempts to summarize our current knowledge in this burgeoning area through a review of key meta-analyses, observational studies, randomized control trials, and Mendelian randomization studies and will hopefully serve as a guide to indicate future research directions and current best practice.

The Paradoxical Role of Uric Acid in Osteoporosis

Because of its high prevalence worldwide, osteoporosis is considered a serious public health concern. Many known risk factors for developing osteoporosis have been identified and are crucial if planning health care needs. Recently, an association between uric acid (UA) and bone fractures had been explored. Extracellular UA exhibits antioxidant properties by effectively scavenging free radicals in human plasma, but this benefit might be disturbed by the hydrophobic lipid layer of the cell membrane. In contrast, intracellular free oxygen radicals are produced during UA degradation, and superoxide is further enhanced by interacting with NADPH oxidase. This intracellular oxidative stress, together with inflammatory cytokines induced by UA, stimulates osteoclast bone resorption and inhibits osteoblast bone formation. UA also inhibits vitamin D production and thereby results in hyper-parathyroidism, which causes less UA excretion in the intestines and renal proximal tubules by inhibiting the urate transporter ATP-binding cassette subfamily G member 2 (ABCG2). At normal or high levels, UA is associated with a reduction in bone mineral density and protects against bone fracture. However, in hyperuricemia or gout arthritis, UA increases bone fracture risk because oxidative stress and inflammatory cytokines can increase bone resorption and decrease bone formation. Vitamin D deficiency, and consequent secondary hyperparathyroidism, can further increase bone resorption and aggravated bone loss in UA-induced osteoporosis.

The Association of Serum Vitamin D Deficiency and Metabolic Risk Factors in Chinese Adults with Prediabetes: A Cross-Sectional Study

The association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with prediabetes (PreDM) has not been investigated. The present study aimed to investigate the association of serum vitamin D deficiency and metabolic risk factors in Chinese adults with PreDM. In this cross-sectional study, we stratified 412 PreDM patients into vitamin D sufficient, vitamin D insufficient and vitamin D deficient subgroups. The physical examination data was collected. Serum 25-hydroxyvitamin D₃ [25(OH)D₃] were measured by high performance liquid chromatography. The prevalence of vitamin D deficiency and insufficiency in PreDM patients were 30.58% and 26.70%, respectively. Compared with the vitamin D deficient group, the prevalence of metabolic syndrome, central obesity, hyperglycemia and hypertension were higher than those in the vitamin D insufficient or sufficient group (p<0.05). Moreover, the prevalence of dyslipidemia in the vitamin D deficient group was higher than those in the vitamin D sufficient group (p<0.05). We observed an inverse relationship between 25(OH)D₃ levels and waist circumference, triglyceride, and serum uric acid (β=-0.315; β=-0.134; β=-0.239), a positive relationship between 25(OH)D₃ levels and high-density lipoprotein cholesterol (β=0.197) after adjusting for age, sex and body mass index. Vitamin D deficiency is very common among PreDM patients in China and this deficiency is related to metabolic risk factors.

Urine albumin and serum uric acid are important determinants of serum 25 hydroxyvitamin D level in pre-dialysis chronic kidney disease patients

Low serum 25 hydroxyvitamin D (25 OH D) is common among chronic kidney disease (CKD) patients. This cross-sectional study is looking for the different factors associated with serum 25 OH D among pre-dialysis CKD. 1624 adult stage 3–5 CKD patients were studied beside 200 normal control subjects. All candidates were tested for body mass index (BMI), estimated glomerular filtration rate (eGFR), calcium (Ca), phosphorus (P), parathormone (PTH), 25 OH D, albumin, and uric acid (UA), and urine albumin/creatinine ratio (ACR). Multivariate linear regression analysis was done to determine predictors of 25 OH D. 98.6% of CKD patients have inadequate level of 25 OH D vs 48% of normal subjects. Serum 25 OH D was significantly lower in CKD patients (mean ± S.D = 16.54 ± 5.8 vs 37.79 ± 3.58 ng/mL for CKD vs control group respectively, p < .001). Serum level of 25 OH D has significant positive correlation with Ca (r = 0.337, p < .001), and significant negative correlation with P, PTH, UA, and ACR (r = −0.440, −0. 679, −0.724, and −0.781respectively, p < .001 in all). The independent predictors of 25 OH D were Ca, P, UA, PTH, and ACR (R square = 0.7, β = −0.087, −0.226, −0.313, −0.253, and −0.33 respectively, p < .001 in all). In conclusion, pre-dialysis CKD patients frequently suffer low 25 OH D. Among the different abnormalities related to CKD, urine albumin excretion rate and UA are the most important predictors of 25 OH D in these patients.

Relationship of Serum Uric Acid Level with Demographic Features, Risk Factors, Severity, Prognosis, Serum Levels of Vitamin D, Calcium, and Magnesium in Stroke

Introduction

Stroke is one of the most common neurological disorders with high mortality rates. A large financial burden is imposed on the families and health systems of countries in addition to the problems related to the disabilities caused by the disease for the patients. Extensive research is being conducted on the disease, including studies seeking possible relationships between some biomarkers such as uric acid and stroke.

Methods

This descriptive-analytic cross-sectional study was conducted on 170 stroke patients at Babol Ayatollah Rohani Hospital during 2015-2016. Serum uric acid (SUA) levels were measured and recorded at admission time. Patients' demographic data as well as the stroke type and some of their risk factors were entered in a checklist. The data were analyzed by SPSS.v.23 using chi-square and logistic regression tests. P < 0.05 was considered as significant in all analyses.

Results

Of the total 170 included patients, 57% had normal, 25% had low, and the remaining patients (18%) had high SUA levels. There was no significant difference in SUA levels in different types of stroke in both genders. Diabetic ischemic embolic patients had higher levels of SUA than diabetic ischemic thrombotic cases. Patients with low magnesium levels had higher rate of low levels of SUA in ischemic stroke.

Conclusion

Serum uric acid levels are not associated with stroke types and gender. Diabetic embolic ischemic stroke cases had high SUA levels than thrombotic types and in ischemic stroke patients with low serum levels of magnesium, SUA levels were also lower.

U-Shaped Association Between Serum Uric Acid Levels With Cardiovascular and All-Cause Mortality in the Elderly: The Role of Malnourishment

BACKGROUND

The link between elevated serum uric acid (SUA) levels and cardiovascular disease (CVD)-related mortality in the elderly population remains inconclusive. Nutritional status influences both SUA and CVD outcomes. Therefore, we investigated whether SUA-predicted mortality and the effect-modifying roles of malnourishment in older people.

METHODS AND RESULTS

A longitudinal Taiwanese cohort including 127 771 adults 65 years and older participating in the Taipei City Elderly Health Examination Program from 2001 to 2010 were stratified by 1-mg/dL increment of SUA. Low SUA (<4 mg/dL) strata was categorized by malnourishment status defined as Geriatric Nutritional Risk Index <98, serum albumin <38 g/L, or body mass index <22 kg/m2. Study outcomes were all-cause and CVD-related mortality. Cox models were used to estimate hazard ratios (HRs) of mortality, after adjusting for 20 demographic and comorbid covariates. Over a median follow-up of 5.8 years, there were 16 439 all-cause and 3877 CVD-related deaths. Compared with the reference SUA strata of 4 to <5 mg/dL, all-cause mortality was significantly higher at SUA <4 mg/dL (HR, 1.16; 95% confidence interval, 1.07-1.25) and ≥8 mg/dL (HR, 1.13; confidence interval, 1.06-1.21), with progressively elevated risks at both extremes. Similarly, increasingly higher CVD-related mortality was found at the SUA level <4 mg/dL (HR, 1.19; confidence interval, 1.00-1.40) and ≥7 mg/dL (HR, 1.17; confidence interval, 1.04-1.32). Remarkably, among the low SUA (<4 mg/dL) strata, only malnourished participants had greater all-cause and CVD-related mortality. This modifying effect of malnourishment remained consistent across subgroups.

CONCLUSIONS

SUA ≥8 or <4 mg/dL independently predicts higher all-cause and CVD-related mortality in the elderly, particularly in those with malnourishment.

An association of smoking with serum urate and gout: A health paradox

BACKGROUND

The potential effect of cigarette smoking on levels of serum urate and risk of gout has been considered by a large number of studies, either as the primary variable of interest or as a covariate.

METHODS

Here we systematically review the published evidence relating to the relationship of smoking with serum urate, hyperuricaemia, and gout.

RESULTS

Many studies have reported that smoking reduces serum urate, however, the evidence has not been conclusive with other studies pointing to the opposite or no effect. It has also been suggested that smoking reduces the risk of gout, although there is some evidence to contradict this finding.

CONCLUSION

A consensus has yet to be reached as to the effect of smoking on serum urate levels and the risk of gout.

Uric acid and bone mineral density in postmenopausal osteoporotic women: the link lies within the fat

The association between serum uric acid (SUA) levels and bone mineral density (BMD) is controversial. Fat accumulation is linked to SUA and BMD, thus possibly explaining the mixed results. We found that adiposity drives part of the association between SUA and BMD in women with postmenopausal osteoporosis.

INTRODUCTION

Both positive and negative associations between SUA and BMD have been reported. SUA levels and BMD increase with higher body weight and other indices of adiposity; hence, the association between SUA and BMD might be a consequence of the confounding effect of adiposity. We investigated in this cross-sectional study whether the association between SUA and BMD is independent of measures of fat accumulation and other potential confounders.

METHODS

SUA levels, femur BMD, markers of bone metabolism, body mass index (BMI), fat mass (FM), waist circumference (WC), and abdominal visceral fat area were measured in 180 treatment-naive postmenopausal osteoporotic women (mean age 66.3 ± 8.5 years, age range 48-81 years).

RESULTS

Women with higher SUA levels (third tertile) had significantly higher femur BMD and lower cross-linked C-terminal telopeptide of type I collagen (CTX) and bone alkaline phosphatase (bALP) levels. SUA levels were positively associated with all indices of adiposity. In multivariable analysis with femur BMD as dependent variable, the association between logarithmic (LG)-transformed SUA levels and BMD (beta = 0.42, p < 0.001) was lessened progressively by the different indices of adiposity, like LG-BMI (beta = 0.22, p = 0.007), LG-WC (beta = 0.21, p = 0.01), LG-FM (beta = 0.18, p = 0.01), and LG-abdominal visceral fat area (beta = 0.12, p = 0.05). The association between SUA levels and markers of bone metabolism was dependent on the effect of confounders.

CONCLUSION

In postmenopausal osteoporotic women, the strong univariable association between SUA levels and femur BMD is partly explained by the confounding effect of indices of adiposity.

The Association of Vitamin D Status and Vitamin D Replacement Therapy with Glycemic Control, Serum Uric Acid Levels, and Microalbuminuria in Patients with Type 2 Diabetes and Chronic Kidney Disease

OBJECTIVE

To evaluate the relationship of vitamin D status and vitamin D replacement therapy with glycemic control, serum uric acid (SUA) levels, and microalbuminuria (MAU) in patients with type 2 diabetes (T2DM) and chronic kidney disease (CKD). Subjectsand Methods: A total of 1,463 patients with T2DM and CKD (aged 14-88 years), 927 females and 536 males, were included in this study. The serum data of 25-hydroxyvitamin D, i.e., 25(OH)D, level, SUA, hemoglobin (Hb)A1c, creatinine, estimated glomerular filtration rate, and urine albumin-to-creatinine ratio (UACR) were obtained from the medical records. The Mann-Whitney U test, the χ2 test, the Mantel-Haenszel test, and linear regression models were used for data analysis.

RESULTS

Vitamin D deficiency and insufficiency were evident in 770 (52.0%) and 357 (24.0%) patients, respectively. Median HbA1c levels (7.3 [IQR 3.9] vs. 6.5 [IQR 2.3]%; p < 0.01) were significantly higher in patients deficient in vitamin D than in those with a normal vitamin D status. A significantly low level of vitamin D was noted with a high UACR (β -0.01; 95% CI -0.01 to -0.001; p = 0.017) and HbA1c (β -1.1; 95% CI -1.6 to -0.6; p < 0.001), but with low levels of SUA (β 1.3; 95% CI 0.5-2.2; p = 0.002). Vitamin D replacement was associated with a significantly low level of HbA1c (7.4 [2.7] vs. 6.7 [1.9]%; p < 0.001].

CONCLUSION

In this study, there was a high prevalence of hypovitaminosis D among T2DM patients with CKD, with a higher UACR, higher HbA1c, and lower SUA being noted as playing a role in predicting a decrease in vitamin D levels and potential benefits of vitamin D replacement therapy on glycemic control in T2DM management.

Relation of Age, Sex and Bone Mineral Density to Serum 25-Hydroxyvitamin D Levels in Chinese Women and Men

OBJECTIVE

To investigate the relation of circulating 25-hydroxyvitamin D (25[OH]D) levels to age, sex, and bone mineral density (BMD) in adults living in Guangzhou Province.

METHODS

This cross-sectional study comprised 188 women and 122 men aged 17-88 years who were randomly sampled among community-dwelling Guangzhou residents. BMD at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry, and serum concentrations of 25(OH)D, parathyroid hormone (PTH), procollagen I N-terminal peptide, and beta C-telopeptide of collagen were assayed by electrochemiluminescence immunoassay. Serum 25(OH)D concentrations were divided into four subgroups: severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (≥30 ng/mL).

RESULTS

The mean age of participants was 47.39 ± 19.32 years. Serum 25(OH)D levels were significantly lower in women than men (25.35 ± 6.59 ng/mL vs 27.25 ± 7.94 ng/mL, P < 0.05). The prevalence of 25(OH)D severe deficiency (<10 ng/mL) was 1.6% in men, zero in women; 25(OH)D deficiency (10-20 ng/mL) was 22.9% in women and 20.5% in men; and 25(OH)D insufficiency (20-30 ng/mL) was 73.4% in women and 65.6% in men. An inverse relationship between serum 25(OH)D levels and age (r = -0.249, P < 0.01) was observed in men, but no correlation was found in women (r = 0.130, P > 0.05). Serum 25(OH)D levels were positively associated with lumbar spine and femoral neck BMD (r = 0.382, P < 0.01; r = 0.384, P < 0.01, respectively) in elderly women and (r = 0.332, P < 0.05; r = 0.260, P < 0.05, respectively) and in young men. When adjustments were made for age, correlations between serum 25(OH)D levels and lumbar spine and femoral neck BMD persisted (r = 0.325, P < 0.05; r = 0.323, P < 0.05, respectively) in elderly women. However, age-adjusted serum 25(OH)D levels were positively correlated with BMD at lumbar spine (r = 0.278, P < 0.05) but not at femoral neck (r = 0.165, P > 0.05) in young men. No association between unadjusted or age-adjusted serum 25(OH)D levels and lumbar spine and femoral neck BMD was found in young and middle-aged women and in middle-aged and elderly men. Neither serum PTH levels nor bone turnover markers were related to unadjusted and age-adjusted serum 25(OH)D levels in our participants.

CONCLUSION

More than two-third of participants residing in Guangzhou had vitamin D insufficiency. Serum 25(OH)D level is an important biomarker for BMD in elderly women and young men.

Association of baseline vitamin D levels with clinical parameters and treatment outcomes in chronic hepatitis B

BACKGROUND & AIMS

The relationship between vitamin D levels and chronic hepatitis B (CHB) infection and treatment outcomes are poorly elucidated. We measured pre-treatment serum vitamin D (25-hydroxyvitamin D3; 25[OH]D3) levels and determined their association with clinical parameters and treatment outcomes in active CHB patients without advanced liver disease enrolled in a global clinical trial.

METHODS

Patients were randomly assigned to either 48 weeks of tenofovir disoproxil fumarate (TDF) plus peginterferon alfa-2a (PegIFN), TDF plus PegIFN for 16 weeks followed by TDF for 32 weeks, PegIFN for 48 weeks, or TDF for 120 weeks. Univariate and multivariate analyses were conducted to determine associations between vitamin D, baseline factors, and week 48 clinical outcome.

RESULTS

Of 737 patients, 35% had insufficient (⩾20 but <31 ng/ml) and 58% had deficient (<20 ng/ml) vitamin D levels. In univariate analysis, lower vitamin D levels were significantly associated with the following baseline parameters: younger age, lower uric acid levels, HBeAg-positive status, lower calcium levels, blood draw in winter or autumn, and HBV genotype D. On multivariate analysis, only HBV genotype, season of blood draw, calcium level, and age retained their association. High baseline level of vitamin D was associated with low HBV DNA, normal ALT and HBsAg at week 48 independent of treatment groups, but the association, with the exception of ALT, became statistically insignificant after adjusting for age, gender, HBeAg and HBV genotype.

CONCLUSIONS

Abnormally low vitamin D levels are highly prevalent among untreated, active CHB patients. Baseline vitamin D levels are not associated with treatment outcomes, but were associated with normal ALT.

Potential causal associations between vitamin D and uric acid: Bidirectional mediation analysis

Vitamin D deficiency, a major public-health worldwide, is associated with hyperuricemia but casual association is questioned. The study was conducted to determine potential causal associations between 25-hydroxy vitamin D (25(OH)D) and uric acid (UA). A cross-sectional study of the Electricity Generating Authority of Thailand (EGAT3) cohort was conducted. Subjects (n = 2,288) were used to genotype the group-specific component (GC) at rs2282679 and ATP-binding cassette subfamily G member 2 (ABCG2) at rs2231142. Mediation analysis with 1000-replication bootstrap was applied to construct causal pathways i.e., rs2282679 → 25(OH)D → UA and rs2231142 → UA → 25(OH)D: The mediator (i.e., 25(OH)D and UA) was firstly regressed on the studied gene (i.e., rs2282679 and rs2231142). A potential causal effect of C allele on UA through 25(OH)D was -0.0236 (95% CI: -0.0411, -0.0058), indicating every minor C allele resulted in decreasing the 25(OH)D and then significantly decreased the UA by 0.0236 unit. For the second pathway, the mediation effect was 0.0806 (95% CI: 0.0107, 0.1628); every T allele copy for rs2231142 increased UA and thus increased 25(OH)D by 0.0806 unit. Our study suggested potential causal associations between the GC gene and UA through the 25(OH)D mediator, and the ABCG2 and the 25(OH)D through the UA mediator but the absolute effects are very clinically small.

Serum urate levels and the risk of hip fractures: data from the Cardiovascular Health Study

PURPOSE

Uric acid inhibits vitamin D activation experimentally and higher serum urate levels are associated with higher parathyroid hormone levels in humans suggesting a link between uric acid and bone health. We hypothesized that hyperuricemia may increase the risk of fractures in older adults.

METHODS

1963 men and 2729 women ≥65 years of age who participated in the Cardiovascular Health Study and had baseline serum urate levels were included in the study. The primary outcome was incident hip fracture, assessed prospectively through June, 2008 by inpatient and outpatient records. The analysis was stratified by sex a priori.

RESULTS

There was a U-shaped relationship between serum urate levels and hip fractures in men. Men in the lowest and the highest urate quartiles (<4.88 and ≥6.88 mg/dL respectively) had a significantly higher rate of fractures in unadjusted analysis. However, upon multivariate adjustment, only the HR for hip fracture in highest quartile versus the reference remained significant (HR 1.9; 95% C.I. 1.1, 3.1; p value 0.02). High serum urate levels were not associated with hip fractures in women.

CONCLUSION

In this large prospective cohort of community-dwelling older adults, increased serum urate levels were associated with an increased risk of hip fractures in men. Further studies are needed to confirm these findings and to understand the mechanisms that underlie them.

The effects of uric Acid, serum vitamin d3, and their interaction on Parkinson's disease severity

Objectives. In current study, the relationships between serum vitamin D3 levels and serum UA concentrations as well as their interaction with severity of PD were evaluated in a sample of Iranian PD patients. Method. In a cross sectional study at the one of the main referral hospitals in central region of Iran, during September to November 2011, 112 patients were recruited. Severity of PD was evaluated sing H&R stages and UPDRS. Results. The Spearman rank correlation coefficient suggests the negative significant association between serum vitamin D3 and UPDRS in patients aged >62 (r = −0.34, P < 0.05). No statistically significant association was observed between the UA levels and severity of PD (represented by H&Y categories) in different levels of serum vitamin D3 not only in total sample but also in separate age and sex groups. The linear regression coefficients suggested positive association between UA and serum vitamin D3 with UPDRSIII scores while negative relationship between UA and serum vitamin D3 interaction with UPDRSIII; however it was only statistically significant in age group ≤62 (P < 0.05). Conclusion. Our study revealed a negative correlation between interaction of serum vitamin D3 and UA with severity of PD; other studies are required to confirm our findings.