Serum uric acid is associated with bone health in older men: a cross-sectional population-based study

Influence of serum uric acid on bone and fracture risk in postmenopausal women

AIMS

Uric acid has been associated with several metabolic conditions, including bone diseases. Our objective here was to consider the relationship between serum uric acid levels and various bone parameters (bone mineral density, ultrasonographic parameters, vitamin D, PTH and serum calcium), as well as the prevalence and risk of fragility fracture.

METHODS

An observational and cross-sectional study carried out on 679 postmenopausal women, classified into 3 groups according to their serum uric acid levels, in whom bone densitometry, calcaneus ultrasounds, PTH, vitamin D and serum calcium analysis were done. Bone fractures were collected through the clinical history and lateral spinal X-ray.

RESULTS

Higher uric acid levels were found in women with older age, high BMI, diabetes, and high blood pressure. Higher levels of PTH and serum calcium were also observed, but did not effect on vitamin D. Serum uric acid was positively related to densitometric and ultrasonic parameters and negatively associated with vertebral fractures.

CONCLUSIONS

In the population of postmenopausal women studied, sUA levels were correlated with BMD, BUA, and QUI-Stiffness, and this correlation was independent of age and BMI. In addition, sUA was associated with a decrease in vertebral fractures. These results imply a beneficial influence of sUA on bone metabolism, with both a quantitative and qualitative positive effect, reflected in the lower prevalence of vertebral fractures.

Elevated uric acid is associated with a low bone mineral density in pre- but not post-menopausal women with rheumatoid arthritis: a pilot study

INTRODUCTION

The role of uric acid (UA) on bone metabolism is controversially discussed. Higher UA levels have been associated with higher T-scores and a reduced incidence of fractures in postmenopausal women. However, in the context of rheumatoid arthritis (RA), the role of UA remains unclear. This pilot study aimed to investigate the association of UA levels with bone mineral density in RA female and male patients.

METHODS

This pilot study analyzed patients with RA to explore preliminary associations. We utilized data from the Rh-GIOP cohort, a prospective monocentric observational study focusing on bone health in chronic rheumatic diseases. To assess the association between UA levels and the lowest T-scores measured at the lumbar spine, hip, or femur, we used linear regression with adjustment for various confounders. An interaction term was included to evaluate differential associations in pre- and postmenopausal women.

RESULTS

Data on dual X-ray absorptiometry (DXA) measurements and serum UA levels were analyzed in a total of 206 patients. Among the 167 women 16 were premenopausal (age 40 ± 8 years) and 149 postmenopausal (age 65 ± 10 years). As expected, postmenopausal had lower T-scores than premenopausal patients (-1.53 ± 1.01 versus - 0.41 ± 1.29, respectively). No association of UA levels with T-scores was found when analyzing the whole cohort (Slope β: -0.04; p = 0.45). However, a significant negative correlation of UA with T-scores in premenopausal (Slope β: -0.98; p = 0.014), but not postmenopausal (Slope β: -0.04; p > 0.05) women was found.

CONCLUSION

Uric acid appears to be negatively associated with bone mineral density in premenopausal but not in postmenopausal women with RA. Thus, the impact of UA on bone health seems to depend on the hormonal status of women. Further investigations are required to validate these results in a larger cohort of patients and to investigate the underlying mechanisms.

BMI mediates the association of serum uric acid with bone health: a cross-sectional study of the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

The associations between serum uric acid and osteoporosis or osteopenia remain controversial, and few studies have explored whether BMI acts as a mediators in the association between the SUA and OP/ osteopenia.

OBJECTIVE

To explore the relationship between serum uric acid and osteoporosis or osteopenia among US adults.

METHODS

A cross-sectional study was conducted to examine the association between serum uric acid and osteoporosis or osteopenia from four cycles of NHANES. Binary logistic regression models and restricted cubic spline models were used to evaluate the association between serum uric acid and osteoporosis or osteopenia, and interaction analysis was used to test the differences between subgroups. Mediation analysis was utilized to investigate whether BMI acts as a mediator in the association between SUA and OP/ osteopenia.

RESULTS

12581 participants aged ≥ 18 years were included. A U-shape nonlinear relationship between SUA and osteoporosis or osteopenia in all people was found (P < 0.0001, P for nonlinear = 0.0287). There were significant interactions in age subgroups (P for interaction = 0.044), sex subgroups (P for interaction = 0.005), and BMI subgroups (P for interaction = 0.017). We further assessed the subgroups and found the optimal range of serum uric acid levels with a lower risk of osteoporosis or osteopenia was 357-535 µmol/L in males, 327-417 µmol/L in people aged ≥ 50 years, above 309 µmol/L in people aged < 50 years, 344-445 µmol/L in people with BMI ≥ 30, and above 308 µmol/L in people with BMI < 30. BMI fully mediated the association of SUA and OP/osteopenia, with a value of -0.0024(-0.0026--0.0021). These results were robust in sensitivity analyses.

CONCLUSIONS

A complicated relationship between SUA and bone health in different populations was observed. Maintaining SUA within a specific range may be beneficial to bone health. In addition, BMI may play an important role in the association between SUA and bone health, but considering the limitations of this study, further prospective research is required.

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 polymorphisms and mutations at rs7125942 and rs3736228 of LRP5 gene and bone metabolism in postmenopausal women

OBJECTIVE

To analyze the relationship between the polymorphism and mutation of rs7125942 and rs3736228 locus in the low-density lipoprotein receptor-related protein 5 (LRP5) genotype and bone mineral density (BMD) in postmenopausal women in Xinjiang, China, to provide a basis for prevention and treatment of the disease.

METHODS

According to the results of dual-energy X-ray (DEXA) determination of BMD, the 136 subjects were divided into three groups: Group A: normal bone mass, Group B: osteopenia, Group C: osteoporosis. 1. Age, body, mass index (BMI), and menopause of all subjects were recorded. 2. Fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), and clinical biochemical data were determined. 3. LRP5 locus polymorphisms were determined by time-of-flight mass spectrometry.

RESULTS

1. Compared with group A, the age, ALP, Cr, and BUN levels in group B and group C were increased, but UA levels were lower (P < 0.05), and Serum P was higher in the group C (P < 0.05). 2. There was no statistically significant difference in the prevalence of diabetes between the three groups (P > 0.05). 3. The ROC curves for different BMD sites such as L1, L2, L3, L4, L total, and femoral neck were 0.929, 0.955, 0.901, 0.914, 0.885, and 0.873 (P < 0.01). 4. At rs7125942 locus, there was statistically significant difference in the distribution of wild-type (CC) and mutant (CG) with the normal bone mass (NBM) group and the abnormal bone mass (ABM) group (P < 0.05). 5. At rs7125942 locus, compared with wild-type (CC), mutant (CG) had lower LDL and FPG in NBM group (P < 0.05), and lower serum ALP in the ABM group (P < 0.05). At rs3736228 locus, the BMD (Femoral neck) of mutant (CT/TT) was lower than that of wild-type (CC) in the NBM group (P < 0.05). 6. Age and menopausal years were negatively correlated with BMD of the femoral neck and L1-4 (P < 0.05), and BMI and TG were positively (P < 0.05), and the results of multiple linear regression analysis showed that age, BMI, and TG were both independent factors affecting BMD (P < 0.05).

Low vitamin D and uric acid status in patients with benign paroxysmal positional vertigo

PURPOSE

Growing evidence reported that vitamin D and uric acid metabolism played roles in the occurrence of benign paroxysmal positional vertigo, an otoconia-related vestibular disorder. We aimed to investigate the serum 25-hydroxy vitamin D (25(OH)D) and uric acid in patients with benign paroxysmal positional vertigo and to determine the risk factor for benign paroxysmal positional vertigo.

METHODS

This case-control study comprised 182 patients with benign paroxysmal positional vertigo and 182 age- and gender-matched controls. All subjects' age, body mass index, systolic blood pressure, diastolic blood pressure, 25-hydroxyvitamin D (25(OH)D), uric acid and serum calcium measurements were analyzed.

RESULTS

We found a female preponderance of benign paroxysmal positional vertigo patients, with a median of 60 (52-66) years old. The results showed low vitamin D status both in benign paroxysmal positional vertigo and controls, with no significant difference of 25(OH)D levels between benign paroxysmal positional vertigo patients and controls (P > 0.05). Compared with the control group, patients with benign paroxysmal positional vertigo had a higher prevalence of vitamin D deficiency and a lower prevalence of vitamin D sufficiency (P < 0.05). Uric acid was significantly lower in the benign paroxysmal positional vertigo groups (P < 0.05). Logistic regression analysis revealed that age and uric acid were considered higher risk predictors for benign paroxysmal positional vertigo.

CONCLUSION

Our study observed low vitamin D status in patients with benign paroxysmal positional vertigo, with no significant differences of the 25(OH)D level in patients with benign paroxysmal positional vertigo and controls. Elderly, vitamin D deficiency and low uric acid levels may be risk factors for benign paroxysmal positional vertigo occurrence.

Moderate elevation of serum uric acid levels improves short-term functional outcomes of ischemic stroke in patients with type 2 diabetes mellitus

BACKGROUND

Serum uric acid (SUA), an end-product of purine catabolism diffused in the blood, is positively associated with the risk of type 2 diabetes mellitus (T2DM). However, in the T2DM population, the association of SUA fluctuation ([Formula: see text]SUA) with the functional outcome of ischemic stroke (IS) is still unclear. Accordingly, this study aimed to assess the correlation between [Formula: see text]SUA and short-term IS functional outcomes in T2DM patients.

METHODS

All T2DM patients diagnosed with IS in the China National Stroke Registry III were included. [Formula: see text]SUA, which was defined as the difference between the SUA levels at baseline and 3 months after symptom onset, was classified into two groups, i.e., elevated [Formula: see text]SUA ([Formula: see text]SUA > 0) and reduced [Formula: see text]SUA ([Formula: see text]SUA [Formula: see text] 0). The outcomes measured using the Modified Rankin Scale (mRS) were scored from 0 to 6, and poor functional outcome was defined as an mRS score of 3-6 at 3 months after IS.

RESULTS

Among the 1255 participants (mean age: 61.6 ± 9.8 years), 64.9% were men. Patients with elevated [Formula: see text]SUA had a lower incidence of poor functional outcomes at 3 months. Compared with reduced [Formula: see text]SUA, elevated [Formula: see text]SUA at 0-50 μmol/L (odds ratio [OR] = 0.46, 95% confidence interval [CI] = 0.28-0.78, p = 0.004) and 50-100 μmol/L (OR = 0.40, 95% CI = 0.21-0.77, p = 0.006) was significantly correlated with a reduced risk of poor functional outcomes at 3 months.

CONCLUSION

This study showed that a moderate increase in [Formula: see text]SUA in the range of 0-100 μmol/L at 3 months after IS might be beneficial in T2DM adults and more studies are warranted to confirm this.

Interplay between fat, muscle, bone mass, and oteophytes and risk for tophaceous gout

Tophaceous gout is a common arthritis caused by the deposition of urate crystals and is related to limited joint function. Although there are reports that uric acid (UA) is associated with bone mineral density (BMD), little is known about the relationship between UA, osteophytes, and muscle. This cross-sectional case-control study was performed in patients with tophaceous gout. The control group included patients without gout. All subjects underwent BMD and body composition analyses. Age, sex, alcohol consumption, smoking, and radiography of both knees were recorded. Adjusted ORs for tophaceous gout were calculated using the logistical regression models. A total of 150 male patients were enrolled, including 65 individuals with tophaceous gout and 85 without gout. The mean age of the patients with tophaceous gout was 59.94±12.40 years, while that of individuals without gout was 61.29±11.57 years (p=0.492). Patients with tophaceous gout have a higher mean body mass index, fat mass, appendicular lean mass, BMD, and osteophytes. Multiple logistic regression analysis revealed that fat mass (OR 2.01, 95% CI 1.27 to 3.18), appendicular lean mass (OR 4.27, 95% CI 1.86 to 9.83), and osteophytes (OR 5.88, 95% CI 1.72 to 20.13) were significantly associated with tophaceous gout. In the current study, higher fat mass, high muscle mass, and osteophyte formation were found to increase the risk of tophaceous gout, as the association is the most than can be inferred from a cross-sectional study. Therefore, reducing body fat and weight management may prevent tophaceous gout.

Association between serum uric acid level and bone mineral density at multiple skeletal sites in middle-aged and elderly men: a cross-sectional study of a healthy population in Taiwan

This study revealed that serum uric acid (sUA) levels were not associated with bone mineral density (BMD) at different skeletal sites in middle-aged and elderly men, even adjusting for confounding variables. Nevertheless, a positive association was only found between sUA levels and BMD at all skeletal sites in the normal BMI group.

INTRODUCTION

Previous studies have reported an association between serum uric acid (sUA) levels and bone mineral density (BMD). However, their findings are controversial and limited to adult men in the general population. This study was aimed at examining the association between sUA levels and BMD at multiple skeletal sites in middle-aged and elderly men.

METHODS

A cross-sectional analysis of BMD at different skeletal sites and sUA levels was conducted on 918 men (age: 50.83 ± 7.95) using data from the Ditmanson Research Database. The participants were categorized into four groups based on quartiles of the sUA level, and BMD were assessed using dual-energy X-ray absorptiometry. Multivariate linear regression models were utilized to investigate the association between sUA levels and BMD. Further, subgroup analyses were performed.

RESULTS

After adjusting for potential confounding factors, sUA as a continuous variable was significantly associated with BMD at the femoral neck only (β, 95% confidence interval: 0.007 [0.001-0.013]). However, in the categorical analysis, no significant differences were detected in terms of BMD at different skeletal sites across the different sUA quartile groups. Moreover, if the body mass index (BMI) was < 24 kg/m² for each unit increase in sUA level, the spine, femoral neck, and total hip BMD increased by 0.014, 0.013, and 0.015 g/cm², respectively.

CONCLUSION

The sUA level was not associated with BMD at different skeletal sites in middle-aged and elderly men. Nevertheless, a positive association was only found between sUA levels and BMD at all skeletal sites in the normal weight group.

Alterations in bone metabolites with age in C57BL/6 mice model

Understanding the pathophysiology behind age-related diseases is an urgent need as the elderly population continues to grow. With age, there is a high risk of musculoskeletal deterioration and associated morbidity and mortality. Although the exact mechanism behind age-related degeneration is unknown, it is well established that alteration in cellular metabolism is one of the important contributing factors. Alteration in signaling pathways with age leads to the accumulation or depletion of several metabolites that play a vital role in musculoskeletal pathophysiology. This study aimed to identify age-related changes in bone tissue metabolites in C57BL/6 mice. We then correlated the differentially expressed metabolites with their functions in bone biology. In both aged males and females, hydroxyproline, glutamine, and alpha-linolenic acid levels were decreased. In aged females, Ornithine (p value = 0.001), L-Proline (p value = 0.008), Uridine (p value = 0.001), Aspartic Acid (p value = 0.004) levels were significantly decreased, and glutamate (p value = 0.002) was elevated. In aged males, N-acetyl-D-glucosamine (pvalue = 0.010), Adrenic acid (pvalue = 0.0099), Arachidonic acid (p value = 0.029) and Allantoin (p value = 0.004) levels were decreased. Metabolic pathway analysis revealed that purine and D-glutamine and D-glutamate metabolism were significantly altered in both sexes, while arginine biosynthesis in females and lipid metabolism in males were highly affected. These differences in metabolic signaling might be one of the reasons for the discrepancy in musculoskeletal disease manifestation between the two sexes. Understanding the role of these metabolites play in the aging bone will allow for new sex-specific targeted therapies against the progression of musculoskeletal diseases.

The paradoxical relation between serum uric acid and outcomes of hip fracture in older patients after surgery: A 1-year follow-up study

BACKGROUND

The relation between serum uric acid and bone metabolism has been reported in many studies, but few studies have focused on serum uric acid and fracture rehabilitation. We aimed to explore the potential relationships between serum uric acid and outcomes of hip fractures.

METHODS

A total of 742 patients with hip fractures who underwent surgeries between December 2017 and February 2021 and met the inclusion criteria were included. The data of male and female patients were analyzed separately. Cox models with different adjusted forms were performed to explore the potential risk factors, and restricted cubic splines were used to determine the nonlinear relationships between serum uric acid and outcomes and optimal cutoff points of serum uric acid. Then, the outcomes were analyzed in the groups divided by cutoff points mentioned above, as well as groups divided by the diagnosis of hyperuricemia or gout.

RESULTS

Cox analysis showed that hyperuricemia or gout was associated with increased death risk, and a typical J-shaped curve was observed in the restricted cubic spline. For male patients, a serum uric acid of high level may relate to a high risk of 6-month (P = .008) and 1-year (P = .016) mortality, and a serum uric acid of low level may predict a poor 6-month free walking ability. For female patients, both a serum uric acid of high level and low level were associated with poor 1-year survival (all P < .05), and a serum uric acid of high level may relate to poor 6-month (P = .001) and 1-year (P = .001) free walking ability.

CONCLUSION

Patients with hyperuricemia or gout or patients with high and low levels of serum uric acid may face poor outcomes of hip fractures.

Hyperuricemia and Its Association with Osteoporosis in a Large Asian Cohort

In this paper, we aimed to examine the protective role of hyperuricemia in the prevalence of osteoporosis in a large Asian cohort. A total of 119,037 participants from 29 recruitment centers in Taiwan were enrolled onto our study. Participants with serum uric acid greater than 7.0 mg/dL in men and 6.0 mg/dL in women were classified as the hyperuricemia group whereas the others were the control group. The mean age of all participants was 50; there were 23,114 subjects (19%) with hyperuricemia. Osteoporosis was observed in 8243 (9%) and 1871 (8%) participants in the control and hyperuricemia groups, respectively. After adjusting for confounders, a lower risk of osteoporosis was found in the hyperuricemia group compared with the control group (odds ratio, 0.916; 95% confidence interval, 0.864 to 0.970). A subgroup analysis showed that hyperuricemia was associated with a lower risk of osteoporosis in females, but not in males. Women with serum uric acid greater than 8.0 mg/dL were not associated with a greater risk of osteoporosis. Our study suggests that hyperuricemia decreases the risk of osteoporosis in females, but not in males. The protective role was no longer apparent when the serum uric acid level was greater than 8 mg/dL.

Prevalence of hyperuricemia and the relationship between serum uric acid concentrations and lipid parameters among King Abdulaziz University Hospital patients

Background

Several studies have associated uric acid with dyslipidemia. However, no previous studies have examined patients without chronic illness.

Aim

: The aim of this study is to assess the relationship between serum uric acid concentration and lipid profile parameters and to estimate the prevalence of hyperuricemia in the city of Jeddah.

Patients and Methods

A retrospective study was conducted on 1206 patients who undergone laboratory blood testing over a 3-year period (2018-2020) at King Abdulaziz University Hospital, which was ethically approved. We used a predesigned checklist to collect data from electronic hospital records using Google Forms. Bivariate analysis, tables, and graphs were used to represent and identify the relationships between variables. A P value of <0.05 was considered significant.

Results

Our study revealed a prevalence of 12% for hyperuricemia in the study population. Males were more frequently affected than females (8.13% vs. 3.73%, respectively). There was no association between serum uric acid concentration and lipid profile parameters, including total cholesterol (P = 0.92), triglyceride (P = 0.42), high-density lipoprotein (P = 0.47), and low-density lipoprotein (P = 0.66). There was a strong association between serum uric acid concentration and high body mass index (P < 0.001), older age (P = 0.002), male sex (P < 0.001), and nationality (P < 0.001). Furthermore, there was an association between sex and mean erythrocyte sedimentation rate (P = 0.02) and mean triglyceride concentration (P = 0.02).

Conclusion

We observed a low prevalence of hyperuricemia, and our results indicate no association between serum uric acid concentration and lipid profile parameters.

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.

Gout in Primary Hyperparathyroidism, connecting crystals to the minerals

Musculoskeletal manifestations in primary hyperparathyroidism (PHPT) range from 13% to 93% encompassing pseudogout, vertebral fracture, myopathy, and cord compression. Though pseudogout has been the most prevalent musculoskeletal condition in PHPT, rarely reports of acute gouty attacks in large joints including the knee have been reported in the literature. Here we detail a unique case of PHPT presenting with acute severe bilateral knee joint inflammatory arthritis accompanied by occasional abdominal pain. Joint aspiration fluid study revealed extracellular monosodium urate crystals exhibiting strong negative birefringence on polarized light microscopy suggestive of acute gouty arthritis. Hypercalcemia and hypophosphatemia with high intact parathyroid hormone (iPTH) confirmed the diagnosis of PHPT and a right inferior parathyroid adenoma was localized. Parathyroidectomy resulted in statistically significant clinical improvement of the debilitating joint manifestations, and the patient was able to walk again without support. Although the incidence of gout is increasing because of an overall increase in metabolic syndrome prevalence, a higher prevalence than in the general population is reported in PHPT. Serum uric acid levels positively correlate with serum iPTH levels in PHPT, and parathyroidectomy leads to a reduction in levels. Acute inflammatory joint pain due to urate crystal deposition in a large joint like the knee is an uncommonly reported condition in PHPT. Identifying the correct etiology in such a case can result in marked clinical improvement in the joint manifestations following surgical cure of hyperparathyroidism.

Assessment of causal associations between uric acid and 25-hydroxyvitamin D levels

BACKGROUND

Previous observational studies have revealed the association between serum uric acid and 25-hydroxyvitamin D. However, the causality and the direction of the associations remain unknown. Thus, we performed a two-sample bidirectional Mendelian Randomization (MR) analysis to investigate the causal association between uric acid and 25-hydroxyvitamin D and to determine the direction of the association.

METHOD

Based on the summary-level GWAS data from large genome-wide association studies, several steps were taken in our analysis to select eligible single-nucleotide polymorphisms (SNPs), which were strongly related to exposure as the instrumental variables. We used different analytical methods, such as inverse-variance weighting (IVW) method, weighted median, MR-Egger regression, and weighted mode method, to make our result more robust and reliable. The IVW method was used as the primary analysis. The Cochran's Q test, MR-Egger intercept test, MR-PRESSO method, and "leave-one-out" sensitivity analysis was performed to evaluate the heterogeneities, horizontal pleiotropy, and robustness of the results. MR analyses were also conducted using genetic risk scores (GRS) as instrumental variables in both directions by using the same summary-level GWAS data.

RESULTS

Our two-sample MR analysis suggested a causal association of genetically predicted uric acid on 25-hydroxyvitamin D [IVW method: β(SE), -0.0352(0.0149); p = 0.0178], which suggested that a per mg/dl increase in uric acid was associated with a decrease of 0.74 nmol/L of 25-hydroxyvitamin D, and the above results remained stable in the sensitivity analysis. By contrast, four MR methods suggested no causal relationship of 25-hydroxyvitamin D on serum uric acid [IVW β(SE), 0.0139 (0.0635); p = 0.826; MR-Egger β(SE), 0.0671 (0.108); p = 0.537; weighted median β(SE), 0.0933 (0.0495); p = 0.0598; weighted mode β(SE), 0.0562 (0.0463); p = 0.228, respectively]. After excluding the SNPs, which were associated with confounding factors and outlier SNPs, the IVW method suggested that there was still no causal association of 25-hydroxyvitamin D on serum uric acid. The GRS approach showed similar results.

CONCLUSIONS

Serum uric acid may causally affect the 25-hydroxyvitamin D levels, whereas the causal role of 25-hydroxyvitamin D on uric acid was not supported in our MR analysis. Our findings suggest that increased levels of uric acid should prompt investigation for vitamin D deficiency.

Relationship of Bone Turnover Markers with Serum Uric Acid-to-Creatinine Ratio in Men and Postmenopausal Women with Type 2 Diabetes

PURPOSE

Accumulating evidence has shown that serum uric acid (UA) is associated with some chronic diseases owing to its antioxidant capacity; however, previous research has discrepant results regarding the relationship between UA and bone health. UA normalized by renal function can reflect endogenous UA levels more precisely than SUA levels. This study assessed the relationship between serum UA-to-creatinine (SUA/Cr) ratio and bone turnover markers (BTMs) in men and postmenopausal women with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

Overall, 1691 patients (1028 males and 663 postmenopausal females) with T2DM admitted to Hebei General Hospital between January and December 2020 were selected and divided into two groups according to their SUA/Cr ratio. One-way analysis of variance was used to compare groups. The relationship between the SUA/Cr ratio and BTMs (including osteocalcin [OC], procollagen I N-terminal peptide [PINP], and β-isomerized type I collagen C-telopeptide breakdown products [β-CTX]) was analyzed using multiple linear regression. Furthermore, subgroup analyses were performed to explore the differences between men and women in the relationship between SUA/Cr and BTMs. Mediation analysis was used to explore whether insulin resistance mediated the association between SUA/Cr and BTMs.

RESULTS

β-CTX and PNIP levels of patients with T2DM in the low SUA/Cr group were significantly higher than those in the high SUA/Cr group, and the difference between the two groups was statistically significant (P < 0.05). Correlation analysis showed that SUA/Cr was negatively correlated with β-CTX and PNIP. After adjusting for confounding factors, multivariate linear regression analysis revealed that the SUA/Cr level was negatively correlated with PINP and β-CTX in male patients and postmenopausal women with T2DM. Stronger correlations were found in patients with 25(OH)D3 < 20ng/mL, course ≥ 5 years, HbA1c > 7%, or BMI < 28 kg/m2.

CONCLUSION

SUA/Cr ratio was an independent influencing factor of BTMs in patients with T2DM.

Increased Glycemic Variability Evaluated by Continuous Glucose Monitoring is Associated with Osteoporosis in Type 2 Diabetic Patients

BACKGROUND

Subjects with type 2 diabetes mellitus (T2DM) are susceptible to osteoporosis. This study was conducted to evaluate the association between glycemic variability evaluated by continuous glucose monitoring (CGM) and osteoporosis in type 2 diabetic patient.

METHODS

A total of 362 type 2 diabetic subjects who underwent bone mineral density (BMD) measurement and were monitored by a CGM system from Jan 2019 to May 2020 were enrolled in this cross-sectional study. Glycemic variability was calculated with the Easy GV software, including 24-hour mean blood glucose (24-h MBG), the standard deviation of 24-h MBG (SDBG), coefficient of variation (CV), mean amplitude of glycemic excursions (MAGE), and time in range between 3.9 and 10.0 mmol/L (TIR). Other potential influence factors for osteoporosis were also examined.

RESULTS

Based on the T-scores of BMD measurement, there were 190 patients with normal bone mass, 132 patients with osteopenia and 40 patients with osteoporosis. T2DM patients with osteoporosis showed a higher 24-h MBG, SDBG, CV, and MAGE, but a lower TIR (all p < 0.05). Multivariate logistic regression analysis revealed that age, female gender, body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), serum uric acid (SUA) and MAGE independently contribute to osteoporosis, and corresponding odds ratio [95% confidence interval (CI)] was 1.129 (1.072-1.190), 4.215 (1.613-11.012), 0.801 (0.712-0.901), 2.743 (1.385-5.431), 0.993 (0.988-0.999), and 1.380 (1.026-1.857), respectively. Further receiver operating characteristic analysis with Youden index indicated that the area under the curve and its 95% CI were 0.673 and 0.604-0.742, with the optimal cut-off value of MAGE predicting osteoporosis being 4.31 mmol/L.

CONCLUSION

In addition to conventional influence factors including age, female gender, BMI, LDL-C and SUA, increased glycemic variability assessed by MAGE is associated with osteoporosis in type 2 diabetic patients.

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.

Association between Serum Uric Acid Levels and Bone Mineral Density in Postmenopausal Women: A Cross-Sectional and Longitudinal Study

Background: Uric acid is one of natural antioxidants in human body. There have been several studies on the correlation between uric acid with oxidative stress and osteoporosis. However, the data are insufficient and results are controversial. In this regard, we determined the association between uric acid levels and bone mineral density (BMD) during the postmenopausal period. Methods: We analyzed data from 328 postmenopausal women (mean age, 57.3 ± 6.5 years; mean serum uric acid level, 4.6 ± 1.0 mg/dL). The participants were divided into three groups based on tertiles of the serum uric acid level. The participants receiving hormone replacement therapy (HRT), bisphosphonates, or lipid-lowering agents were included. Results: Blood urea nitrogen, serum creatinine, and serum triglyceride levels were significantly higher in the upper tertiles of uric acid levels. No significant difference was found in the mean uric acid levels between medication users and non-users. Each HRT regimen had a different mean serum uric acid level. A cross-sectional analysis showed no significant correlation between the serum uric acid levels and BMD in the spine and femoral neck (spine BMD: 1.050 ± 0.131, 1.060 ± 0.160, 1.084 ± 0.140, p = 0.22; femoral neck BMD: 0.837 ± 0.110, 0.849 ± 0.096, 0.863 ± 0.115, p = 0.28 for each tertile of uric acid). Longitudinal analysis of data from 186 women with follow-up examinations at a mean interval of 14.6 months also revealed no difference in reduction in both spine and femoral neck BMD between tertile groups of serum uric acid (the median BMD reduction for spine: −0.02, 0.01, −0.04, p = 0.95; the median BMD reduction for femoral neck: 0.008, 0.005, −0.003, p = 0.34). Conclusions: Serum uric acid level is not associated with BMD in postmenopausal women.

No association between serum uric acid and lumbar spine bone mineral density in US adult males: a cross sectional study

Available evidence linking serum uric acid (SUA) and bone mineral density (BMD) remains controversial, and data on this association are limited among adult men in the general population. Thus, the aim of this study was to evaluate the association of SUA with lumbar spine BMD in US adult males. A cross-sectional study was conducted based on the National Health and Nutrition Examination Survey (NHANES, 1999–2006) database. Multivariate linear regression analyses were employed to assess the association of SUA with lumbar spine BMD, considering complex survey design and sampling weights. Through rigorous eligibility criteria, a total of 6704 individuals were yielded for final data analysis (average age, 40.5 years; 70.6% white). After fully adjusting potential confounders, no associations were detected between SUA and lumbar spine BMD [β (95% confidence interval, CI), − 0.003 (− 0.007, 0.002)]. Additionally, similar results were observed in all stratification analyses, and no interactions were found based on all priori specifications. In brief, our findings did not provide an inspiring clue for the hypothesis that SUA may be beneficial to lumbar spine BMD. Future more prospective studies are needed to further explore the causal relationship of SUA with lumbar spine BMD.

Analyses of the relationship between hyperuricemia and osteoporosis

The aim of the present study was to evaluate the association between hyperuricemia and osteoporosis in a Korean population. Data from participants of the Korean Genome and Epidemiology Study who were ≥ 40 years old were collected from 2004 to 2016. Among 173,209 participants, 11,781 with hyperuricemia (> 7.0 mg/dL in men and > 6.0 mg/dL in women) and 156,580 controls were selected based on serum measurements. Odds ratios (ORs) of osteoporosis between individuals with hyperuricemia and controls were analyzed using a logistic regression model. In the adjusted model, age, sex, income group, body mass index, smoking, alcohol consumption, hypertension, diabetes mellitus, hyperlipidemia history and nutritional intake were adjusted. The adjusted OR (aOR) of osteoporosis was 0.79 [95% confidence interval (CI) = 0.71–0.87, P < 0.001]. In subgroup analyses according to age and sex, statistical significance was observed in men > 60 years old and in women > 50 years old. In another subgroup analysis according to past medical history, significant differences were found according to hypertension (aOR = 0.83, 95% CI = 0.73–0.94, and 0.75, 95% CI = 0.64–0.87), diabetes mellitus (aOR = 0.77, 95% CI = 0.69–0.86), and hyperlipidemia (aOR = 0.74, 95% CI = 0.61–0.89, and 0.81, 95% CI = 0.72–0.91). This study demonstrated that hyperuricemia was associated with a decreased risk of osteoporosis.

Urine and Serum Electrolytes and Biochemical Values Associated with Osteoporosis in Premenopausal and Postmenopausal Women: A Longitudinal and Cross-Sectional Study Using Korean Genome and Epidemiology Study (KoGES) Cohort

Osteoporosis is a major public health concern, especially in women. This study aims to identify early biomarkers from biochemical measurements of serum and urine for recognizing the development of osteoporosis and osteopenia in premenopausal and postmenopausal women. From the Korean Genome and Epidemiology Study (KoGES) cohort, longitudinal study participants with normal bone density were enrolled and assessed for the association of baseline clinical and biochemical factors with osteoporosis development over 4 years. In addition, a cross-sectional study between normal bone density and osteopenia/osteoporosis was conducted to validate the risk factors found in the longitudinal cohort. Of the 5272 female participants in the KoGES cohort, 813 women (501 premenopausal and 312 menopausal) who had normal bone density at baseline were included in the longitudinal study. During the 4 years of follow-up, 64 patients developed osteoporosis and 354 developed osteopenia. In a multivariate logistic regression analysis, serum calcium and urine uric acid levels were significantly associated with elevated osteoporosis risk in premenopausal and postmenopausal women, respectively (risk of osteoporosis by serum calcium levels in premenopausal women: 4.03 (1.09–14.93), p = 0.037; risk of osteoporosis by urine uric acid levels in postmenopausal women: 24.08 (1.79–323.69), p = 0.016). For the cross-sectional study, serum and urine parameters were compared between women with osteopenia or osteoporosis at baseline and those with normal bone density. Urine uric acid levels were found to be significantly higher in both premenopausal and postmenopausal women with bone loss than in women with normal bone density (p < 0.001 and p = 0.004, respectively). Uric acid level in urine may be an early marker for the development of osteoporosis in women, especially after menopause.

Elevated Urate Levels Do Not Alter Bone Turnover Markers: Randomized Controlled Trial of Inosine Supplementation in Postmenopausal Women

OBJECTIVE

Observational studies have consistently demonstrated that serum urate level positively correlates with bone mineral density (BMD). We undertook this study to determine whether moderate hyperuricemia induced by inosine supplements influences bone turnover markers in postmenopausal women over a 6-month period.

METHODS

One hundred twenty postmenopausal women were recruited for a 6-month randomized, double-blind, placebo-controlled trial. Key exclusion criteria were osteoporosis, previous fragility fracture, bisphosphonate therapy, gout, kidney stones, and a urine pH level of ≤5.0. Participants were randomized in a 1:1 ratio to receive placebo or inosine. The coprimary end points were change in levels of N-propeptide of type I procollagen (PINP) and change in levels of β-C-telopeptide of type I collagen (β-CTX). Change in BMD, as measured by dual x-ray absorptiometry, was an exploratory end point.

RESULTS

Administration of inosine led to a significant increase in serum urate concentration over the study period (P < 0.0001 for all follow-up time points). At week 26, the mean change in serum urate concentration was +0.13 mmoles/liter (+2.2 mg/dl) in the inosine group and 0.00 mmoles/liter (0 mg/dl) in the placebo group. There was no difference in PINP or β-CTX levels between groups over the 6 months. There were no significant changes in bone density between groups over the 6 months. Adverse events and serious adverse events were similar between the 2 groups.

CONCLUSION

This clinical trial shows that although inosine supplementation leads to sustained increases in serum urate levels over a 6-month period, it does not alter markers of bone turnover in postmenopausal women. These findings do not support the concept that urate has direct biologic effects on bone turnover.

Serum Uric Acid Level Is Positively Associated With Higher Bone Mineral Density at Multiple Skeletal Sites Among Healthy Qataris

BACKGROUND

Oxidative stress has been implicated as a fundamental mechanism in the decline of bone mass. Although serum uric acid (SUA) has potent antioxidant properties, the findings of many epidemiological and experimental studies couldn't draw a clear conclusion on the relation between SUA and bone health. We aim to investigate the association between SUA and bone mineral density (BMD) at different skeletal sites among healthy Qataris.

METHODOLOGY

A cross-sectional analysis including total-body and site-specific bone mineral density scores and other serological markers of 2981 healthy Qatari adults (36.4 ± 11.1 years) from the Qatar biobank database was conducted. The study participants were divided into quartiles based on the level of SUA, and the BMD was measured using dual-energy X-ray absorptiometry (DXA). Multiple regression analyses were applied to investigate the association between SUA and BMD adjusting for multiple confounding factors.

RESULTS

High levels of SUA were significantly associated with the increased bone mineral density of the total body and at site-specific skeletal locations after adjusting for age and gender (p-value < 0.001). Further adjustment for body mass index (BMI), smoking, vitamin D, alkaline phosphatase, and estimated glomerular filtration rate (eGFR) levels attenuated the association but the association remained significant for individuals with high SUA levels (p-value ≤ 0.01).The association between SUA and BMD was not significant in non-obese, females, young adults, and smokers. However, no interaction was found between SUA and age, gender, BMI and smoking.

CONCLUSION

Higher SUA levels are associated with a high bone density among healthy Qatari adults. However, such observation demands further investigations to outline the underlying mechanisms.

Association between the metabolome and bone mineral density in a Chinese population

BACKGROUND

Osteoporosis is a common metabolic bone disease, which always leads to osteoporotic fractures. Biomarkers of bone mineral density (BMD) are helpful for prevention and early diagnosis of osteoporosis. This study aims to identify metabolomic biomarkers of low BMD.

METHODS

We included 701 participants who had BMD measures by dual-energy X-ray absorptiometry scans and donated fasting plasma samples from three clinical centres as a discovery set and another 278 participants from the fourth centre as an independent replication set. We used a liquid chromatography-mass spectrometry-based metabolomics approach to profile the global metabolites of fasting plasma.

FINDINGS

Among the 265 named metabolites identified in our study, six were associated with low BMD (FDR-adjusted P<0.05) in the discovery set and were successfully validated in the independent replication set. The circulating levels of five metabolites, i.e., inosine, hypoxanthine, PC (O-18:0/22:6), SM (d18:1/21:0) and isoleucyl-proline were associated with decreased odds of low BMD, and PC (16:0/18:3) level was associated with increased odds of low BMD. Per 1-SD increase in a composite metabolite score of these six metabolites was associated with about half decreased odds of low BMD (odds ratio 0.59, 95% confidence interval: 0.52-0.68). Furthermore, introduction of a panel of metabolites selected by elastic net regression to a prediction model of classical risk factors and plasma biomarker of bone resorption substantially improved the prediction performance for low BMD (AUCs: 0.782 vs. 0.698, P=0.002).

INTERPRETATION

Metabolomics profiling may help identify novel biomarkers of low BMD and be helpful for early diagnosis of osteoporosis beyond the current clinical index.

FUNDING

This study was supported by the National Key R&D Program of China [2018YFC2001500 to J.S.], Shanghai Municipal Science and Technology Major Project [2017SHZDZX01], the National Natural Science Foundation of China [Key Program, 91749204 to J.S.], the National Natural Science Foundation of China [General Program, 81771491 to J.S.], the Project of Shanghai Subject Chief Scientist [2017BR011 to J.S.], Grants from the TCM Supported Project [18431902300 to J.S.] from the Science and Technology Commission of Shanghai Municipality, and the National Natural Science Foundation of China [General Program, 81972089 to Z.X.]. Y.Z. was supported by the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, and the National Natural Science Foundation of China [81973032].

Relationships between serum uric acid concentrations, uric acid lowering medications, and vertebral fracture in community-dwelling elderly Japanese men: Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Cohort Study

PURPOSE

The association between serum concentrations of uric acid (UA), a potent endogenous antioxidant, and fracture risk has not yet been examined for morphometric vertebral fracture (VF). This study aimed to determine whether serum UA concentrations are associated with risks of clinical osteoporotic fracture (OPF) and morphometric VF after adjusting for confounding factors including UA-lowering medications (ULMs).

MATERIALS AND METHODS

A total of 2012 Japanese men aged ≥65 years completed the baseline study, which included serum UA measurement and X-ray absorptiometry-based VF assessment. We conducted a follow-up study five years later to identify incident OPFs and VFs. OPF was identified through interviews. Incident VF was defined as a vertebra which showed reduction in any of its anterior, central, or posterior heights by ≥20% during follow-up, and satisfied grade one or higher fracture criteria in Genant's method on follow-up images. Bone mineral density (BMD) of the hip and spine was measured by dual-energy X-ray absorptiometry at baseline and follow-up.

RESULTS

We identified 45 clinical OPFs from 2000 men and 39 VFs from 1530 men during a mean follow-up period of 4.3 years. Hip BMD was significantly higher in higher UA concentration groups after adjusting for age and body mass index. A significantly decreased multivariate-adjusted odds ratio (OR) of incident VF was observed for the highest quartile groups of serum UA concentrations compared with the lowest quartile group (OR: 0.17, 95% confidence interval: 0.05-0.62). This OR remained significant after further adjusting for ULM use. ULM users in the lowest quartile group of serum UA concentrations had a significantly higher incidence rate of VF compared to the other quartile groups.

CONCLUSIONS

Higher serum UA concentrations were associated with a lower risk of morphometric VF independently of ULM in Japanese elderly men. Excessive reduction of serum UA concentrations by ULM might increase VF risk.

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.

The urinary β2 microglobulin-creatinine ratio is inversely associated with lumbar spine bone mineral density in the elderly Chinese males

Renal tubule cells play a pivotal role in maintaining bone homeostasis. Hence, renal tubular function may be associated with bone mineral density. Our study found that urinary β₂ microglobulin-creatinine ratio (UBCR) levels correlated negatively with lumbar spine bone mineral density (BMD) and T and Z values, and may be a marker for osteoporosis in Chinese elderly male adults.

PURPOSE

To study the association of UBCR levels with BMD and the predictive value of UBCR for osteoporosis in elderly Chinese male adults.

METHODS

A cross-sectional study of 149 (65 to 85 years, 69.7 ± 4.6) Chinese male adults who underwent health checkups in Huadong Hospital in Shanghai China was conducted. BMD was measured by dual-energy X-ray absorptiometry. The clinical variables and BMD of the participants in the low UBCR group (B1, UBCR < 300 μg/g) and the high UBCR group (B2, UBCR ≥ 300 μg/g) were compared. Associations between UBCR with clinical variables and BMD were analyzed by Pearson's correlation coefficient and multiple regression analysis. BMD and T and Z values were compared between the B1 and B2 groups. The odds ratios (ORs) for dose-dependent increases in osteoporosis between B1 and B2 were analyzed by binary logistic regression analysis. The area under the receiver operating characteristic (ROC) curve was used to analyze the capacity of UBCR to predict osteoporosis.

RESULTS

UBCR was significantly higher in the osteoporosis group. After adjusting for multiple confounders, UBCR levels correlated negatively with BMD and T and Z values of the lumbar spine. Lumbar spine BMD and T and Z values were significantly lower in the B2 UBCR group than in the B1 UBCR group. Compared with the B1 participants, the ORs for "osteoporosis" were 12.401 times higher in B2 participants (P = 0.005) by binary logistic regression analysis after adjusting for potential confounders. The UBCR index (cutoff = 362.48 μg/g) had a sensitivity of 78.6% and a specificity of 68.7% for identifying osteoporosis, with an area under the ROC curve of 0.760.

CONCLUSIONS

These results suggest that UBCR levels correlate negatively with lumbar spine BMD and T and Z values and may serve as a marker for osteoporosis in Chinese elderly male adults.

Higher serum uric acid levels are associated with reduced risk of hip osteoporosis in postmenopausal women with rheumatoid arthritis

Although the positive correlation between serum uric acid (UA) levels and bone mineral density (BMD) has been reported in the general population, there are little data regarding the effect of serum UA levels on bone loss in patients with rheumatoid arthritis (RA).We investigated whether increased serum UA levels were associated with a reduced risk of osteoporosis in postmenopausal women with RA.In this retrospective cross-sectional study, 447 postmenopausal female patients with RA and 200 age-matched, postmenopausal healthy controls underwent BMD examination by dual energy x-ray absorptiometry and serum UA levels measurement. Osteoporosis was diagnosed when the T-score was <-2.5.The median UA level in postmenopausal RA patients was found to be significantly lower than that in the healthy women (4 vs 4.1 mg/dL, P = .012) and the frequency of osteoporosis incidence in the lumbar spine, hip, and either site in RA patients was 25.5%, 15.9%, and 32.5%, respectively; the values were significantly higher than those of the controls. After adjusting for confounding factors, a significantly lower risk for osteoporosis of the hip in RA patients was observed within the highest quartile (odds ratio [OR] = 0.37, 95% confidence interval [CI] = 0.16-0.72, P = .021) and the second highest quartile (OR = 0.44, 95% CI = 0.2-0.95, P = .038) of serum UA levels as compared with the lowest quartile, but this association was not found to be consistent with respect to the lumbar spine. Serum UA levels also showed an independently positive correlation with femoral neck BMD (β = 0.0104, P = .01) and total hip BMD (β = 0.0102, P = .017), but not with lumbar BMD.Our data suggest that UA may exert a protective effect on bone loss in RA, especially in the hip.

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.

Bone microstructure and volumetric bone mineral density in patients with hyperuricemia with and without psoriasis

We analyzed volumetric bone mineral density (vBMD) and bone microstructure using HR-pQCT in subjects with normouricemia (NU) and subjects with hyperuricemia (HU) with and without psoriasis (PSO). HU was associated with higher cortical vBMD and thickness. Differences in average and trabecular vBMD were found between patients with PSO + HU and NU.

INTRODUCTION

Hyperuricemia (HU) and gout are co-conditions of psoriasis and psoriatic arthritis. Current data suggest a positive association between HU and areal bone mineral density (BMD) and a negative influence of psoriasis on local bone, even in the absence of arthritis. However, the influence of the combination of HU and psoriasis on bone is still unclear. The aim of this study was to assess the impact of HU with and without psoriasis on bone microstructure and volumetric BMD (vBMD).

METHODS

Healthy individuals with uric acid levels within the normal range (NU), with hyperuricemia (HU), patients with hyperuricemia and psoriasis (PSO + HU), and patients with uric acid within the normal range and psoriasis (PSO + NU) were included in our study. Psoriasis patients had no current or past symptoms of arthritis. Average, trabecular, and cortical vBMD (mgHA/cm³); trabecular number (Tb.N, 1/mm) and thickness (Tb.Th, mm); inhomogeneity of the network (1/N.SD, mm); and cortical thickness (Ct.Th., mm) were carried out at the ultradistal radius using high-resolution peripheral quantitative computed tomography. In addition, bone turnover markers such as DKK-1, sclerostin, and P1NP were analyzed.

RESULTS

In total, 130 individuals were included (44 NU participants (34% female), 50 HU (24%), 16 PSO + HU (6%), 20 PSO + NU (60%)). Subjects were aged: NU 54.5 (42.8, 62.1), HU 57.5 (18.6, 65.1), PSO + HU 52.0 (42.3, 57.8), and PSO + NU 42.5 (34.8, 56.8), respectively. After adjusting for age, sex, BMI, and diabetes, patients in the HU group revealed significantly higher values of cortical vBMD (p < 0.001) as well as cortical thickness (p = 0.04) compared to the NU group. PSO + NU showed no differences to NU, but PSO + HU demonstrated both lower average (p = 0.03) and trabecular vBMD (p = 0.02). P1NP was associated with average, cortical, and trabecular vBMD as well as cortical thickness while sclerostin levels were related to trabecular vBMD.

CONCLUSION

Hyperuricemia in otherwise healthy subjects was associated with a better cortical vBMD and higher cortical thickness. However, patients with both psoriasis and hyperuricemia revealed a lower vBMD.

Association between Uric Acid and Bone Mineral Density in Postmenopausal Women with Type 2 Diabetes Mellitus in China: A Cross-Sectional Inpatient Study

OBJECTIVE

To analyze the association between uric acid levels and bone mineral density in postmenopausal women with type 2 diabetes mellitus.

METHODS

We retrospectively analyzed 262 postmenopausal women with type 2 diabetes mellitus, to assess uric acid levels and bone mineral density using the T score of dual-energy X-ray absorptiometry.

RESULTS

(1) Women in the osteoporosis group demonstrated higher uric acid levels and lower estimated glomerular filtration rate (p < 0.05, respectively). (2) Uric acid levels were positively correlated with the hip and lumbar spine bone mineral density and T score (r = 0.17, p < 0.05; r = 0.25, p < 0.05; r = 0.17, p < 0.05; and r = 0.28, p < 0.05, respectively). Meanwhile, there was a positive relation between estimated glomerular filtration rate and hip bone mineral density (r = 0.22, p < 0.05). (3) Logistic regression analysis showed that age, body mass index, and diabetic duration are independent risk factors for osteoporosis in postmenopausal women with type 2 diabetes mellitus. The level of estimated glomerular filtration rate and uric acid levels were not independent effect factors for osteoporosis in menopausal women.

CONCLUSION

Uric acid levels are neither a protective factor nor a risk factor for osteoporosis in women with type 2 diabetes mellitus.

Serum Uric Acid Shows Inverted "U" Type Correlation with Osteoporosis in Chinese Ankylosing Spondylitis Patients: A Retrospective Study

Background

This study was to investigate the correlation between osteoporosis and serum uric acid in ankylosing spondylitis (AS) patients, and to further identify potential factors that might be associated with osteoporosis in AS patients.

Material/Methods

We included 182 AS patients, consisted of 143 male patients and 39 female patients, who visited our hospital from January 1, 2014 to December 31, 2018. We used dual-energy x-ray absorptiometry to measure bone mineral density (BMD) of orthotopic lumbar vertebrae in patients with AS. The gender, age, disease duration, BMD, T-score, Z-score, uric acid, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), blood platelet (PLT), and status of treatment with biologics of the patients were collected. Then, the Spearman correlation coefficient and multivariate liner regression analysis were applied to identify the relationship between the factors and BMD, T-score, and Z-score in AS patients.

Results

Male AS patients between the ages of 16 and 30 years old had a higher risk of osteoporosis (P<0.05). AS patients with uric acid value between 300–360 μmol/L had the highest BMD, T-score, and Z-score. The BMD had a positive correlation with age and disease duration (P<0.01) while had a negative correlation with PLT (P<0.05). BMD in AS patients with elevated ESR was significantly (P<0.05) lower than in AS patients with normal ESR. There were no significant differences in BMD between AS patients with elevated CRP and the patients with normal CRP and PLT. Treatment with TNFi (tumor necrosis factor alpha inhibitor) did not improve BMD in AS patients.

Conclusions

The relationship between uric acid and BMD in AS patients was observed as inverted “U”-type. Keeping uric acid within 300–360 μmol/L might be helpful in preventing AS patients from developing osteoporosis.

Biomarkers of Osteoporosis: An Update

Background:

Osteoporosis, characterized by compromised bone quality and strength is associated with bone fragility and fracture risk. Biomarkers are crucial for the diagnosis or prognosis of a disease as well as elucidating the mechanism of drug action and improve decision making.

Objective:

An exhaustive description of traditional markers including bone mineral density, vitamin D, alkaline phosphatase, along with potential markers such as microarchitectural determination, trabecular bone score, osteocalcin, etc. is provided in the current piece of work. This review provides insight into novel pathways such as the Wnt signaling pathway, neuro-osseous control, adipogenic hormonal imbalance, gut-bone axis, genetic markers and the role of inflammation that has been recently implicated in osteoporosis.

Methods:

We extensively reviewed articles from the following databases: PubMed, Medline and Science direct. The primary search was conducted using a combination of the following keywords: osteoporosis, bone, biomarkers, bone turnover markers, diagnosis, density, architecture, genetics, inflammation.

Conclusion:

Early diagnosis and intervention delay the development of disease and improve treatment outcome. Therefore, probing for novel biomarkers that are able to recognize people at high risk for developing osteoporosis is an effective way to improve the quality of life of patients and to understand the pathomechanism of the disease in a better way.

Association between serum uric acid and bone health in adolescents

Previous studies are suggestive of the protective role of uric acid on bone in the middle-aged and elderly. Whether this association exists in younger individuals has not been examined. This investigation showed a significant positive association between serum uric acid and bone parameters among Iranian adolescents.

INTRODUCTION

Uric acid (UA) might be linked to bone health, but it is unclear whether its effects on bone are limited to certain population subgroups. This study is aimed at investigating the correlation between serum uric acid levels and bone mineral density (BMD) in Iranian adolescents.

METHODS

This cross-sectional study was conducted on 413 (221 girls and 192 boys) Iranian adolescents aged 9-19 years. An analysis of anthropometric, biochemical parameters and bone density was performed on the participants. Measurements included serum uric acid, calcium, phosphorus, alkaline phosphatase, albumin, and vitamin D. They were divided according to their serum UA into the low UA group who had UA ≤ 6 mg/dL and the high UA group with UA > 6 mg/dL. BMD and bone mineral content (BMC) were measured in the total body, lumbar spine, and left femoral neck, using dual energy X-ray absorptiometry (DXA), and bone mineral apparent density (BMAD) was calculated.

RESULTS

A Pearson correlation analysis revealed a significant correlation between UA and bone parameters. In multiple regression analyses adjusted for potential confounders, serum UA was proven to be associated with BMD and BMC at all sites. There was no association between UA, serum calcium, and vitamin D concentrations.

CONCLUSION

Our study, as the first research on adolescents, demonstrated a higher bone density in those who had higher UA levels.

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.

Serum Uric Acid Status and Its Association with Bone Mineral Density in the Elderly People Aged 60 Years and More

BACKGROUND

Osteoporosis is associated with decreased antioxidant defenses and serum uric acid (UA) as an antioxidant may exert a protective effect on bone mass.

OBJECTIVES

This study aimed to determine the association between serum UA and bone mineral density (BMD) in the elderly population.

METHODS

All participants of the Amirkola Health and Ageing Project aged ≥ 60 years entered the study. BMD in the femoral neck (FN-BMD) and lumbar spine (LS-BMD) was determined by dual energy X-ray absorptiometry and osteoporosis was defined as BMD T-score < - 2.5 at either FN or LS. The patients were classified according to serum UA levels as < 4; 4 - 4.99; 5 - 5.99; 6 - 6.99 and > 7 mg/dL. In statistical analysis, the value of BMD as well as frequency of osteoporosis in each subgroup were compared with the control group (UA < 4 mg/dL).

RESULTS

A total of 1080 patients were studied. By increasing serum UA from < 4 mg/dL to > 7 mg/dL the BMD at both measurement sites increased as well. The serum UA was associated with decreased risk of osteoporosis. In multivariate analysis, the odds of osteoporosis in the subgroup with serum UA levels between 4 - 4.99 mg/dL was significantly lower than the control group (OR = 0.66, 95% CI, 0.44 - 0.99). Age and female sex were associated with increased odds of osteoporosis (OR = 1.08, 95% CI, 1.05 - 1.10 and OR = 10.62, 95% CI, 7.53 - 14.97 respectively).

CONCLUSIONS

These findings indicate a negative association between serum UA and osteoporosis in the elderly population aged ≥ 60 years.

Specific higher levels of serum uric acid might have a protective effect on bone mineral density within a Chinese population over 60 years old: a cross-sectional study from northeast China

Background and objective: Oxidative stress has been demonstrated to be a mechanism that leads to bone mass reduction, and according to many studies, serum uric acid (UA) is a strong endogenous antioxidant that can protect bone mineral density (BMD). To date, there have been no large-scale, cross-sectional studies based on the population in northeast China to assess the relationship between serum UA and BMD. Therefore, we examined the association between serum UA and BMD among a Chinese population older than 60 years old in northeast China.

Methods: This research was a cross-sectional study of 3465 Chinese individuals over 60 years old in nine communities from the city of Shenyang, which is the capital of northeast China’s Liaoning Province. Participants were stratified into three groups by serum UA or BMD levels, and then Pearson’s correlation analysis and multiple regression analysis were used to study the relationship between serum UA and BMD.

Results: We found that participants with higher serum UA levels had significantly greater BMD and T-values compared to those of participants with lower serum UA levels. After adjusting for confounding factors, Pearson’s correlation analysis and multiple regression analysis showed that higher serum UA levels remained associated with higher BMD levels (P<0.05). In different models, the prevalence of osteoporosis (OP) among participants with higher serum UA levels was reduced by 23% to 26% (P<0.05) compared to that in individuals with lower serum UA levels. In addition, serum UA levels were negatively correlated with estimated glomerular filtration rate (eGFR) and positively correlated with 25-hydroxy vitamin D₃ [25-(OH)D₃] (P<0.05).

Conclusion: We concluded that higher serum UA levels are associated with greater BMD, and serum UA might have a protective effect on bone metabolism due to its antioxidant properties.

Review of the Literature Examining the Association of Serum Uric Acid with Osteoporosis and Mechanistic Insights into Its Effect on Bone Metabolism

Background And Objective:

Osteoporosis is a common bone disorder that increases susceptibility to fragility bone fractures. The clinical and public health repercussions of osteoporosis are huge due to the morbidity, mortality, and cost of medical care linked with fragility fractures. Clinical assessment of osteoporotic risk factors can help to identify candidates at an early stage that will benefit from medical intervention and potentially lowering the morbidity and mortality seen with fractures and complications. Given this, research is ongoing to evaluate the association of osteoporosis with some novel or less well-studied risk factors/bio-markers such as uric acid (UA).

Discussion:

Uric acid’s antioxidant activity has been proposed to be one of the factors responsible for increasing longevity and lowering rates of age-related cancers during primate evolution, the level of which increased markedly due to loss of uricase enzyme activity (mutational silencing). Accumulated evidence shows that oxidative stress is the fundamental mechanism of age-related bone loss and acts via enhancing osteoclastic activity and increasing bone resorption. Antioxidant substances such as ascorbic acid scavenge free radicals are positively related to bone health. Thus, it is hypothesized that uric acid holds bone-protective potential owing to its potent antioxidative property. Several correlation studies have been conducted globally to investigate the relationship between serum uric acid with bone mineral density and osteoporosis. Few pre-clinical studies have tried to investigate the interaction between uric acid and bone mineral density and reported important role played via Runt-related transcription factor 2 (RUNX2)/core-binding factor subunit alpha-1 (CBF-alpha-1), Wingless-related integration site (Wnt)-3a/β-catenin signaling pathway and 11β Hydroxysteroid Dehydrogenase type 1.

Conclusion:

In this review, the authors provided a comprehensive summary of the literature related to association studies reported in humans as well work done until date to understand the potential cellular and molecular mechanisms that interplay between uric acid and bone metabolism.

Higher serum uric acid is associated with higher lumbar spine bone mineral density in male health-screening examinees: a cross-sectional study

Bone health has been associated with oxidative stress and antioxidants have received interest to this end. Serum uric acid (SUA), an end product of purine metabolism in humans, has recently shown antioxidant properties regarding bone health, but there are conflicting results. The aim of this study was to investigate the relationship between SUA levels and lumbar spine bone mineral density (BMD) in clinically apparently healthy males aged 40-60 years. We performed a cross-sectional study of 6588 Korean males who completed a health-screening program from January 2011 to December 2014. Of the study participants, the mean age was 48.2 ± 10.7 years. Multiple regression analyses resulted in a significant positive association with lumbar spine BMD across SUA quintiles in a dose-response manner after adjusting for various confounding factors (p = 0.013); for each 1 mg/dl increase of SUA, BMD rose by 0.0054 g/cm² (p = 0.004). Stratified analyses revealed that this association between SUA and lumbar spine BMD was consistently observed across all clinically relevant subgroups. The present study demonstrated a positive association in males between SUA and lumbar spine BMD, suggesting that SUA could have a profitable effect on bone metabolism.

Serum Uric Acid Could Differentiate Acute Myocardial Infarction and Unstable Angina Pectoris in Hyperuricemic Acute Coronary Syndrome Patients

Introduction:

Serum uric acid (SUA) is the final product of purine metabolism in humans.

Aim:

The present study aimed to identify a potential association between serum UA and cardiac troponin I (cTnI) levels and to find out whether uric acid could differentiate patients presenting with the acute myocardial infarction (AMI) and unstable angina pectoris (UAP) in hyperuricemic and normouricemic acute coronary syndrome (ACS) patients.

Methods:

Eighty ACS patients, aged 50-83 years, were enrolled in the study, 40 of them presenting with AMI and 40 with UAP. Frequency of patients with serum uric level over threshold for hyperuricemia was investigated and two groups of patients were formed such as hyperuricemic and normouricemic groups (A and B groups, respectively) independently of type of ACS. Those groups of patients were also subjected to cTnI measurement.

Results:

Levels of SUA are associated with the type of ACS in the hyperuricemic ACS patients (AMI versus UAP, 499(458-590), 425(400-447) mmol/L, p=0.007, respectively). Uric acid correlated significantly with cTnI, moderate positively in the group A (rho=0.358, p=0.038) and moderate negatively in the group B (r=-0.309, p=0.037) of ACS patients. Multiple logistic regression analysis revealed that cTnI and age were independently associated with the SUA levels in the group A of ACS patients.

Conclusions:

Serum uric acid differentiates AIM and UAP patients in hyperuricemic group of acute coronary syndrome. Therefore it can be used as nonspecific parameter for evaluation of the myocardial lesion extent only in hyperuricemic ACS patients. This is supported by finding that cTnI along with age predicts SUA level in hyperuricemic ACS patients.