Project description:BackgroundObservational 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).MethodsWe 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.ResultsThe 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.ConclusionsOur 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.
Project description:Previous observational studies have shown that the serum uric acid (UA) level is decreased in persons with multiple sclerosis (MS). We used the two-sample Mendelian randomization (MR) method to determine whether the serum UA level is causally associated with the risk of MS. We screened 26 single-nucleotide polymorphisms (SNPs) in association with serum UA level (p < 5 × 10-8) from a large genome-wide meta-analysis involving 110,347 individuals. The SNP outcome effects were obtained from two large international genetic studies of MS involving 38,589 individuals and 27,148 individuals. A total of 18 SNPs, including nine proxy SNPs, were included in the MR analysis. The estimate based on SNP rs12498742 that explained the largest proportion of variance showed that the odds ratio (OR) of UA (per mg/dl increase) for MS was 1.00 [95% confidence interval (CI) 0.90-1.11; p = 0.96]. The main MR analysis based on the random effects inverse variance weighted method showed that the pooled OR was 1.05 (95% CI 0.92-1.19; p = 0.50). Although there was no evidence of net horizontal pleiotropy in MR-Egger regression (p = 0.48), excessive heterogeneity was found via Cochran's Q statistic (p = 9.6 × 10-4). The heterogeneity showed a substantial decrease after exclusion of two outlier SNPs (p = 0.17). The pooled ORs for the other MR methods ranged from 0.89 (95% CI 0.65-1.20; p = 0.45) to 1.05 (95% CI 0.96-1.14; p = 0.29). The results of sensitivity analyses and additional analyses all showed similar pooled estimates. MR analyses by using 81 MS -associated SNPs as instrumental variables showed that genetically predicted risk of MS was not significantly associated with serum UA level. The pooled OR was 1.00 (95% CI 0.99-1.02; p = 0.74) for the main MR analysis. This MR study does not support a causal effect of genetically determined serum UA level on the risk of MS, nor does it support a causal effect of genetically determined risk of MS on serum UA level.
Project description:The relationship between serum uric acid (UA) levels and cancer risk remains controversial. Here, a two-sample Mendelian randomization analysis was performed to identify a causal effect of serum UA levels on cancer risk. Twenty-six single nucleotide polymorphisms strongly associated with serum UA levels were screened as genetic variants from large-scale meta-analysis data of a genome-wide association study of 110,347 European individuals. Genetic associations with eight common site-specific cancers were subsequently explored. A total of six Mendelian randomization methods were used to estimate the potential effect of serum UA levels on cancer risk, including random effects inverse variance weighting, fix effects inverse variance weighting, MR-Egger, median weighting, mode weighting, and simple mode analysis. Our primary random effects inverse variance weighted analysis revealed that no significant associations with cancers was found (all p > 0.05). Sensitivity analyses and additional analyses also showed similar pooled results. In conclusion, no significant causality between serum UA levels and cancer risk was evidenced.
Project description:ObjectiveThe effects of coffee consumption on serum uric acid (SUA) levels and gout risk are controversial. There have hitherto been no reports based on Mendelian randomization (MR) analysis of its effects that consider pleiotropy. Here, we evaluated the effects of coffee consumption across ancestry populations, taking pleiotropy into account.MethodsWe performed the first MR analyses for coffee consumption on SUA levels and gout, considering pleiotropy. We used the following summary statistics of genome-wide association studies from a Japanese population: habitual coffee consumption (152,634 subjects), gout (3053 cases and 4554 controls), and SUA levels (121,745 subjects). In addition to fixed-effect inverse variance weighted (IVW) meta-analysis, we performed a robust evaluation of heterogeneity and removed several instruments for reasons of possible pleiotropy. Previous European datasets were also reevaluated while heterogeneity was considered.ResultsHabitual coffee consumption was significantly and inversely associated with gout (odds ratio [OR] = 0.29, 95% confidence interval [95% CI]: 0.16-0.51, P = 1.9 × 10-5 ) in random-effect IVW (Phet = 5.5 × 10-19 ). Excluding pleiotropic instruments, the protective effect on gout was confirmed in fixed-effect IVW analysis (OR = 0.75, 95% CI: 0.58-0.97, P = 0.026) without heterogeneity (Phet = 0.39). However, we observed no significance in the previous European datasets when heterogeneity was considered. Associations were not observed between coffee consumption and SUA levels in either ancestry in MR analyses that considered pleiotropy. Multivariable MR analysis showed that increased coffee consumption significantly reduced gout risk, even after adjusting for SUA levels (OR = 0.50, 95% CI: 0.31-0.81, P = 0.0046).ConclusionWith pleiotropy taken into account, our MR analyses revealed that coffee consumption can causally reduce gout risk, and that it may reduce gout risk independently of SUA levels.
Project description:Limited Mendelian randomization (MR) studies have assessed the causal relationship between serum uric acid levels and diabetes risk. Here we investigated causality between the serum uric acid concentration and diabetes risk in Chinese population. The observational analysis, based on the Dongfeng-Tongji prospective cohort (n=15 195) we tested the association of serum uric acid levels with incident diabetes risk. In the instrumental variable analysis, we examined the association of the genetic risk score (GRS) of serum uric acid with diabetes risk in case-control design (2539 cases and 4595 controls) via MR analysis. During a mean (SD) follow-up of 4.5 (0.5) years, 1156 incident diabetes cases were identified. Compared with those in the lowest quintile of serum uric acid levels, the HRs of incident diabetes were 1.19 (95% CI 0.96 to 1.48), 1.12 (95% CI 0.90 to 1.40), 1.38 (95% CI 1.12 to 1.70), and 1.51 (95% CI 1.23 to 1.87) for Q2, Q3, Q4 and Q5, respectively (P-trend <0.001). The GRS was strongly associated with serum uric acid levels (β=0.17, 95% CI 0.15 to 0.19; P=2.81×10-67). However, no significant association was observed between the GRS and diabetes risk (OR=1.01, 95 CI 0.95 to 1.06; P=0.75). Even though serum uric acid levels were significantly associated with increased incident diabetes risk, the results did not provide evidence for a causal relationship between them.
Project description:BackgroundAlthough the relationship between serum uric acid (SUA) and adiposity is well established, the direction of the causality is still unclear in the presence of conflicting evidences. We used a bidirectional Mendelian randomization approach to explore the nature and direction of causality between SUA and adiposity in a population-based study of Caucasians aged 35 to 75 years.Methods and findingsWe used, as instrumental variables, rs6855911 within the SUA gene SLC2A9 in one direction, and combinations of SNPs within the adiposity genes FTO, MC4R and TMEM18 in the other direction. Adiposity markers included weight, body mass index, waist circumference and fat mass. We applied a two-stage least squares regression: a regression of SUA/adiposity markers on our instruments in the first stage and a regression of the response of interest on the fitted values from the first stage regression in the second stage. SUA explained by the SLC2A9 instrument was not associated to fat mass (regression coefficient [95% confidence interval]: 0.05 [-0.10, 0.19] for fat mass) contrasting with the ordinary least square estimate (0.37 [0.34, 0.40]). By contrast, fat mass explained by genetic variants of the FTO, MC4R and TMEM18 genes was positively and significantly associated to SUA (0.31 [0.01, 0.62]), similar to the ordinary least square estimate (0.27 [0.25, 0.29]). Results were similar for the other adiposity markers.ConclusionsUsing a bidirectional Mendelian randomization approach in adult Caucasians, our findings suggest that elevated SUA is a consequence rather than a cause of adiposity.
Project description:ObjectivesThis study aimed to explore the potential causal associations between serum uric acid (SUA) and the risk of colorectal cancer, colon cancer and rectal cancer.MethodsTwenty-six SUA-related single nucleotide polymorphisms which were identified by a large meta-analysis of genome-wide association studies (GWASs) were used as instrumental variables in the two-sample Mendelian randomization (MR) study. Meta-analyses were used to synthesize the results of multiple GWASs which were extracted from the MRC Integrative Epidemiology Unit GWAS database for each type of cancer. The inverse variance weighted (IVW) method was used as the primary MR method to analyze the association between SUA and colorectal cancer risk. Several sensitivity analyses were performed to test the robustness of results.ResultsThe IVW method showed that there were no causal relationships between SUA and the risk of colorectal cancer [odds ratio (OR): 1.0015; 95% confidence interval (CI): 0.9975-1.0056] and colon cancer (OR: 1.0015; 95% CI: 0.9974-1.0055). The SUA levels were negative correlated with rectal cancer risk (OR: 0.9984; 95% CI: 0.9971-0.9998). The similar results were observed in both males (OR: 0.9987; 95% CI: 0.9975-0.9998) and females (OR: 0.9985; 95% CI: 0.9971-0.9999). The sensitivity analyses suggested no evidence of heterogeneity or horizontal pleiotropy. The leave-one-out analyses showed that one SNP (rs1471633) significantly drove the causal effect of SUA on rectal cancer risk. The MR-Egger regression and weighted median both showed that there were no causal relationships between SUA and the risk of colorectal cancer and its subtypes.ConclusionOverall, there was no linear causal association between SUA and the risk of colorectal cancer. However, further research is needed to investigate the role of higher SUA levels such as hyperuricemia or gout in the occurrence of colorectal cancer.
Project description:Increased serum urate predicts chronic kidney disease independent of other risk factors. The use of xanthine oxidase inhibitors coincides with improved renal function. Whether this is due to reduced serum urate or reduced production of oxidants by xanthine oxidase or another physiological mechanism remains unresolved. Here we applied Mendelian randomization, a statistical genetics approach allowing disentangling of cause and effect in the presence of potential confounding, to determine whether lowering of serum urate by genetic modulation of renal excretion benefits renal function using data from 7979 patients of the Atherosclerosis Risk in Communities and Framingham Heart studies. Mendelian randomization by the two-stage least squares method was done with serum urate as the exposure, a uric acid transporter genetic risk score as instrumental variable, and estimated glomerular filtration rate and serum creatinine as the outcomes. Increased genetic risk score was associated with significantly improved renal function in men but not in women. Analysis of individual genetic variants showed the effect size associated with serum urate did not correlate with that associated with renal function in the Mendelian randomization model. This is consistent with the possibility that the physiological action of these genetic variants in raising serum urate correlates directly with improved renal function. Further studies are required to understand the mechanism of the potential renal function protection mediated by xanthine oxidase inhibitors.
Project description:Purpose:Although increasing lines of evidence showed associations between serum uric acid (UA) levels and schizophrenia, the causality and the direction of the associations remain uncertain. Thus, we aimed to assess whether the relationships between serum UA levels and schizophrenia are causal and to determine the direction of the association. Patients and Methods:Two-sample bidirectional Mendelian randomization (MR) analyses and various sensitivity analyses were performed utilizing the summary data from genome-wide association studies within the Global Urate Genetics Consortium and the Psychiatric Genomics Consortium. Secondary MR analyses in both directions were conducted within summary data using genetic risk scores (GRSs) as instrumental variables. Results:Three MR methods provided no causal relationship between serum UA and schizophrenia. Furthermore, GRS approach showed similar results in the three MR methods after adjustment for heterogeneity. By contrast, inverse variance weighted method, weighted median and GRS approach suggested a causal effect of schizophrenia risk on serum UA after adjustment for heterogeneity (per 10-symmetric percentage increase in schizophrenia risk, beta: -0.039, standard error (SE): 0.013, P = 0.003; beta: -0.036, SE: 0.018, P = 0.043; beta: -0.039, SE: 0.013, P = 0.002; respectively). Moreover, in both directions' analyses, the heterogeneity and sensitivity tests suggested no strong evidence of bias due to pleiotropy. Conclusion:Schizophrenia may causally affect serum UA levels, whereas the causal role of serum UA concentrations in schizophrenia was not supported by our MR analyses. These findings suggest that UA may be a useful potential biomarker for monitoring treatment or diagnosis of schizophrenia rather than a therapeutic target for schizophrenia.
Project description:BackgroundThe role of uric acid on metabolic syndrome (MetS) has always been controversial. This study aims to explore associations between uric acid with MetS and its components in Chinese female health check-up population.Methods1381 subjects constituted the longitudinal health check-up cohort. Health examination and genotyping were performed. Unadjusted and adjusted observational analyses were implemented to evaluate observational associations between uric acid with MetS and its components. Mendelian randomization analysis was performed to estimate the causal effect using variation at rs11722228 (SLC2A9) as an instrument for uric acid.ResultsAn increase of 65% in risk of MetS per standard deviation increase in uric acid was found using unadjusted observational analyses. This association attenuated on adjustment for potential confounders. Similar patterns were found in the association analyses of uric acid with hyperglycemia, hypertension, and dyslipidemia. Neither by performing unadjusted nor adjusted analysis did we see evidence for association of uric acid on overweight and obesity. Mendelian randomization analyses showed no evidence of causal association between uric acid and MetS and MetS components.ConclusionsWe found no causal evidence to support that increased serum uric acid is a causal risk factor for MetS or its components. Hence, there remains no strong evidence for the effeteness of undergoing urate-lowering therapy to prevent the onset of MetS or cardiovascular disease in health management.