Uric acid level, gout and bone mineral density: A Mendelian randomization study

The causal relationship between anti-diabetic drugs and gastrointestinal disorders: a drug-targeted mendelian randomization study

BACKGROUND

The incidence of diabetic gastrointestinal diseases is increasing year by year. This study aimed to investigate the causal relationship between antidiabetic medications and gastrointestinal disorders, with the goal of reducing the incidence of diabetes-related gastrointestinal diseases and exploring the potential repurposing of antidiabetic drugs.

METHODS

We employed a two-sample Mendelian randomization (TSMR) design to investigate the causal association between antidiabetic medications and gastrointestinal disorders, including gastroesophageal reflux disease (GERD), gastric ulcer (GU), chronic gastritis, acute gastritis, Helicobacter pylori infection, gastric cancer (GC), functional dyspepsia (FD), irritable bowel syndrome (IBS), ulcerative colitis (UC), Crohn's disease (CD), diverticulosis, and colorectal cancer (CRC). To identify potential inhibitors of antidiabetic drug targets, we collected single-nucleotide polymorphisms (SNPs) associated with metformin, GLP-1 receptor agonists, SGLT2 inhibitors, DPP-4 inhibitors, insulin, and its analogs, thiazolidinediones, sulfonylureas, and alpha-glucosidase inhibitors from published genome-wide association study statistics. We then conducted a drug-target Mendelian randomization (MR) analysis using inverse variance weighting (IVW) as the primary analytical method to assess the impact of these inhibitors on gastrointestinal disorders. Additionally, diabetes was selected as a positive control.

RESULTS

Sulfonylureas were found to significantly reduce the risk of CD (IVW: OR [95% CI] = 0.986 [0.978, 0.995], p = 1.99 × 10- 3), GERD (IVW: OR [95% CI] = 0.649 [0.452, 0.932], p = 1.90 × 10- 2), and chronic gastritis (IVW: OR [95% CI] = 0.991 [0.982, 0.999], p = 4.50 × 10- 2). However, they were associated with an increased risk of GU development (IVW: OR [95%CI] = 2 0.761 [1.259, 6.057], p = 1 0.12 × 10- 2).

CONCLUSIONS

The results indicated that sulfonylureas had a positive effect on the prevention of CD, GERD, and chronic gastritis but a negative effect on the development of gastric ulcers. However, our research found no causal evidence for the impact of metformin, GLP-1 agonists, SGLT2 inhibitors, DPP 4 inhibitors, insulin and its analogs, thiazolidinediones, or alpha-glucosidase inhibitors on gastrointestinal diseases.

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.

Long-Term Differential Effects of Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density

Context

The association of obesity with bone fragility fractures is complex and non-linear. Despite good efficacy on weight loss, bariatric surgery (BS) is also associated with bone loss. However, we lack information on risk factors of the long-term deleterious effects of BS on the skeleton.

Objective

We aimed to assess the factors associated with low bone mineral density (BMD) performed a long time after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG).

Methods

This cross-sectional study involved patients at a long distance from their BS that underwent dual-energy x-ray absorptiometry (DXA) with biological factors (vitamins, micronutrients, bone and inflammation biomarkers). Simple and multiple linear models (stepwise and parsimony approach) were developed.

Results

A total of 131 patients (91 RYGB, 40 SG) underwent DXA (51.8 ± 11.08 years, 87.8% women). At a mean of 6.8 ± 3.7 years after surgery, the mean weight loss was -28.6 ± 9.6%, and only 6 patients (5.7%) had a T-score less than or equal to -2.5. On univariate analysis, BMD was lower in the RYGB than in the SG group (P < .001) at all sites, despite similar fat and fat-free mass and weight loss. Serum parathyroid hormone and phosphate levels were higher in RYGB than SG patients. A total of 10.1% of patients showed vascular calcifications. On multivariable analysis, BMD remained different between surgery groups after adjustment for age, body mass index, ethnicity, and sex. The model-adjusted R 2 values were 0.451 for the total hip; 0.462 the femoral neck, and 0.191 the lumbar spine for the inflammation model; 0.458, 0.462, and 0.254, respectively, for the bone marker model; and 0.372, 0.396, and 0.142 for the vitamin model. Serum zinc, ferritin, and uric acid levels were the markers associated with BMD to a low extent.

Conclusion

BMD differed depending on the BS procedure. A few biological markers may be associated weakly with BMD well after the surgery.

A Mendelian randomization study of serum uric acid with the risk of venous thromboembolism

BACKGROUND

Observational studies have linked hyperuricemia with venous thromboembolism (VTE). We aimed to investigate whether there are causal relationships between uric acid levels and VTE and its subtypes, including deep venous thrombosis (DVT) of the lower extremities and pulmonary embolism (PE).

METHODS

We utilized Mendelian randomization (MR) analysis to estimate the causal association in European individuals. We extracted two sets of polygenic instruments strongly associated (p < 5 × 10^-8) with uric acid from the CKDGen consortium and UK biobank, respectively. Genetic associations with the risk of VTE, DVT, and PE were obtained from the FinnGen biobank. We used the inverse-variance weighted method as the preliminary estimate. Additionally, we employed MR-Egger, weighted median, and Mendelian randomization pleiotropy residual sum and outlier method as complementary assessments. Sensitivity analyses were performed to test for pleiotropic bias.

RESULTS

The genetically instrumented serum uric acid levels had no causal effects on VTE, DVT, and PE. Two sets of polygenic instruments used for exposure, along with three complementary MR methods, also yielded no significant association.

CONCLUSIONS

Our MR analysis provided no compelling evidence for a causal relationship of serum uric acid with the risk of VTE. This suggests that uric acid-lowering therapies in patients with hyperuricemia may not be effective in reducing the likelihood of developing VTE.

Epidemiology and treatment-related concerns of gout and hyperuricemia in Korean

Gout is the most common form of inflammatory arthritis that affects mainly middle-aged men, and there is clear evidence of an association between hyperuricemia and the risk for gout. Increasing prevalence of gout and hyperuricemia has been reported in many countries. The prevalence of gout and hyperuricemia are constantly increasing in Korea with the patients at risk for developing a variety of comorbidities. Although there have been studies on the association between gout or serum uric acid level and several neurodegenerative diseases, cancer, and cardiovascular mortality, the causal relationship between gout and these comorbidities are still unclear. The associations of substantial economic burden with hyperuricemia, gout attack, and suboptimal treatment are well known. Gout is a disease that requires lifelong management including lifestyle modification. However, gout is poorly managed worldwide although effective urate-lowering drugs exist. In this review, we addressed epidemiological studies and treatment-related problems in the Korean population with gout or hyperuricemia to obtain the best clinical outcomes and reduce their medical burden.

Causal relationship between particulate matter 2.5 and hypothyroidism: A two-sample Mendelian randomization study

Background

Epidemiological surveys have found that particulate matter 2.5 (PM_2.5) plays an important role in hypothyroidism. However, due to the methodological limitations of traditional observational studies, it is difficult to make causal inferences. In the present study, we assessed the causal association between PM_2.5 concentrations and risk of hypothyroidism using two-sample Mendelian randomization (TSMR).

Methods

We performed TSMR by using aggregated data from genome-wide association studies (GWAS) on the IEU Open GWAS database. We identified seven single nucleotide polymorphisms (SNPs) associated with PM_2.5 concentrations as instrumental variables (IVs). We used inverse-variance weighting (IVW) as the main analytical method, and we selected MR-Egger, weighted median, simple model, and weighted model methods for quality control.

Results

MR analysis showed that PM_2.5 has a positive effect on the risk of hypothyroidism: An increase of 1 standard deviation (SD) in PM_2.5 concentrations increases the risk of hypothyroidism by ~10.0% (odds ratio 1.10, 95% confidence interval 1.06-1.13, P = 2.93E-08, by IVW analysis); there was no heterogeneity or pleiotropy in the results.

Conclusion

In conclusion, increased PM_2.5 concentrations are associated with an increased risk of hypothyroidism. This study provides evidence of a causal relationship between PM_2.5 and the risk of hypothyroidism, so air pollution control may have important implications for the prevention of hypothyroidism.

Hyperuricemia and gout: effects on bone and articular cartilage (literature review)

Gout is a disease characterized by deposition of sodium monourate crystals in tissues which is the reason of inflammation among persons with hyperuricemia (HU). The prevalence of HU, which can be considered the first stage of gout formation, varies in different countries. Despite this, only a small number of persons with HU have been shown to develop symptoms of gout. Recent data suggest that HU is an independent risk factor for cartilage and bone damage. UA, both in the form of crystals and in a dissolved form, activates damage and potentiates cell death by releasing reactive oxygen species, activating the necroptosis pathway, neutrophil traps, synthesis of pro-inflammatory cytokines, and other pathogenetic mechanisms that cause the negative effects of HU and gout on articular cartilage and subchondral bone. The association of HU and osteoarthritis (OA) is well known and based on the common pathogenesis, but the direction of this relationship is still a debatable issue. The accumulated data suggest the need for a deeper study of the relationship of gout and asymptomatic HU with pathological processes leading to the development and progression of OA and disorders of bone metabolism.

Matrix Metalloproteinases in Relation to Bone Mineral Density: A Two-Sample Mendelian Randomization Study

Background: We aimed at investigating causal associations between matrix metalloproteinases (MMPs) and bone mineral density (BMD) by the Mendelian randomization (MR) analysis. Methods: From genome-wide association studies of European ancestry, we selected instrumental variables for MMP-1, MMP-3, MMP-7, MMP-8, MMP-10, and MMP-12. Accordingly, we retrieved summary statistics of three site-specific BMD, namely, forearm, femoral neck, and lumbar spine. We conducted an inverse variance weighted MR as the primary method to compute overall effects from multiple instruments, while additional MR approaches and sensitivity analyses were implemented. Bonferroni-adjusted significance threshold was set at p < 0.05/18 = 0.003. Results: Totally, there was no evidence for causal effects of genetically-predicted levels of MMPs on BMD measurement at three common sites. MR results indicated that there were no causal associations of circulating MMPs with forearm BMD (all p ≥ 0.023) by the inverse variance weighted method. Similarly, there were no causal effects of MMPs on femoral neck BMD (all p ≥ 0.120) and MR results did not support causal relationships between MMPs and lumbar spine BMD (all p ≥ 0.017). Multiple sensitivity analyses suggested the robustness of MR results, which were less likely to be biased by unbalanced pleiotropy or evident heterogeneity. Conclusion: We found no evidence for the causal relationship between MMPs and BMD in the European population.

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.

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 of Serum Uric Acid Status With Bone Mineral Density in Adolescents Aged 12-19 Years

Aims: Evidence linking serum uric acid (sUA) and bone mineral density (BMD) in adolescents is very limited. To the best of our knowledge, only one report has focused on the relationship between sUA and BMD in adolescents. Thus, this study aimed to determine the association between sUA and total BMD in adolescents aged 12-19 years. Methods: A cross-sectional study was conducted on a sample composed of non-institutionalized US population from the National Health and Nutrition Examination Survey. Weighted multivariate linear regression models were used to evaluate the association between sUA and total BMD. Subgroup analyses were further performed. Results: sUA positively correlated with total BMD in the multiple regression model after adjusting for potential confounders. However, in the subgroup analyses stratified by sex, age, or race/ethnicity, the association between sUA and total BMD followed an inverted U-shaped curve in female adolescents, adolescents aged 16-19 years, and other race/ethnicity. Conclusions: Our results suggested that the correlation between sUA level and total BMD differed by sex. The increased sUA level would be beneficial to bone health in adolescents with low sUA levels, but for female adolescents, a higher sUA level (turning point, 3.9 mg/dL) may have an adverse effect on bone health.

The Association between Serum Uric Acid and Bone Mineral Density in Older Adults

OBJECTIVES

Uric acid has been found to be potentially protective in bone metabolism. We investigated the relationship between serum uric acid (sUA) and lumbar bone mineral density (BMD) among 4156 participants aged 60 years and over from the National Health and Nutrition Examination Survey (NHANES).

METHODS

To estimate the association between sUA and lumbar BMD, multivariate logistic regression analyses were conducted. Fitted smoothing curves and generalized additive models were also performed.

RESULTS

We found sUA positively correlated with lumbar BMD after adjusting for other confounders. On subgroup analyses, stratified by sex and race/ethnicity, the positive correlation of sUA with lumbar BMD remained in both men and women, as well as in whites and Mexican Americans, but not in blacks. In blacks, the association of sUA with lumbar BMD was an inverted U-shaped curve (inflection point: 7.5 mg/dL).

CONCLUSIONS

Our study revealed a positive relationship between sUA and lumbar BMD among most old adults. This association followed an inverted U-shaped curve among blacks.