scholarly journals Epidemiological and Mendelian Randomization Studies of Dihydrotestosterone and Estradiol and Leukocyte Telomere Length in Men

2016 ◽  
Vol 101 (3) ◽  
pp. 1299-1306 ◽  
Author(s):  
Bu B. Yeap ◽  
Matthew W. Knuiman ◽  
Mark L. Divitini ◽  
Jennie Hui ◽  
Gillian M. Arscott ◽  
...  
Keyword(s):  
Telomere Length ◽  
Mendelian Randomization ◽  
Leukocyte Telomere Length

scholarly journals Association of leukocyte telomere length with chronic kidney disease in East Asians with type 2 diabetes: A Mendelian randomization study

2021 ◽  
Author(s):  
Resham L Gurung ◽  
Rajkumar Dorajoo ◽  
Yiamunaa M ◽  
Ling Wang ◽  
Sylvia Liu ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Telomere Length ◽  
Mendelian Randomization ◽  
Random Effect ◽  
Leukocyte Telomere Length ◽  
Increased Risk ◽  
Genetically Determined

Abstract Background Chronic kidney disease (CKD) is common among type 2 diabetes (T2D) and increases the risk of kidney failure and cardiovascular diseases. Shorter leukocyte telomere length is associated with CKD in patients with T2D. We previously reported single nucleotide polymorphisms (SNPs) associated with leukocyte telomere length in Asian population. In this study, we elucidated the association of these SNPs with CKD in patients with T2D using Mendelian randomization (MR) approach. Methods The cross-sectional association of 16 leukocyte telomere length SNPs with CKD, defined as an estimated glomerular filtration rate of less than 60 ml/min/1.73m2 was assessed among 4,768 (1,628 cases, 3,140 controls) participants in the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes and Diabetic Nephropathy cohorts. MR analysis was performed using the random-effect inverse-variance weighted (IVW) method, the weighted median, MR-Egger and Radial MR adjusted for age and sex-stratified by cohorts and ethnicity (Chinese and Malays), then meta-analysed. Results Genetically determined shorter leukocyte telomere length was associated with increased risk of CKD in patients with T2D (meta-IVW adjusted odds ratio = 1.51 [95% confidence interval, 1.12 - 2.12; P = 0.007; Phet= 0.547]). Similar results were obtained following sensitivity analysis. MR-Egger analysis (intercept) suggested no evidence of horizontal pleiotropy (β  =  0.010, P = 0.751). Conclusions Our findings suggest that genetically determined leukocyte telomere length is associated with CKD in patients with T2D. Further studies are warranted to elucidate the causal role of telomere length in CKD progression.

scholarly journals Leukocyte telomere length and amyotrophic lateral sclerosis: a Mendelian randomization study

2021 ◽  
Author(s):  
Kailin Xia ◽  
Linjing Zhang ◽  
Gan Zhang ◽  
Yajun Wang ◽  
Tao Huang ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Telomere Length ◽  
Causal Relationship ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
Genome Wide Association Studies ◽  
Leukocyte Telomere Length ◽  
Weighted Median ◽  
Lateral Sclerosis

Abstract Background Observational studies have suggested that telomere length is associated with amyotrophic lateral sclerosis (ALS). However, it remains unclear whether this association is causal. We employed a two-sample Mendelian randomization (MR) approach to explore the causal relationship between leukocyte telomere length (LTL) and ALS based on the most cited and most recent and largest LTL genome-wide association studies (GWASs) that measured LTL with the Southern blot method (n = 9190) and ALS GWAS summary data (n = 80,610). We adopted the inverse variance weighted (IVW) method to examine the effect of LTL on ALS and used the weighted median method, simple median method, MR Egger method and MR PRESSO method to perform sensitivity analyses. Results We found that genetically determined longer LTL was inversely associated with the risk of ALS (OR = 0.846, 95% CI: 0.744–0.962, P = 0.011), which was mainly driven by rs940209 in the OBFC1 gene, suggesting a potential effect of OBFC1 on ALS. In sensitivity analyses, that was confirmed in MR Egger method (OR = 0.647,95% CI = 0.447–0.936, P = 0.050), and a similar trend was shown with the weighted median method (OR = 0.893, P = 0.201) and simple median method (OR = 0.935 P = 0.535). The MR Egger analyses did not suggest directional pleiotropy, showing an intercept of 0.025 (P = 0.168). Neither the influence of instrumental outliers nor heterogeneity was found. Conclusions Our results suggest that genetically predicted longer LTL has a causal relationship with a lower risk of ALS and underscore the importance of protecting against telomere loss in ALS.

scholarly journals Long Leukocyte Telomere Length Is Associated with Increased Risks of Soft Tissue Sarcoma: A Mendelian Randomization Study

Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 594 ◽  
Author(s):  
Yifan Xu ◽  
Junfeng Xu ◽  
Haidee Chancoco ◽  
Maosheng Huang ◽  
Keila E. Torres ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Telomere Length ◽  
Mendelian Randomization ◽  
Genetic Risk Score ◽  
Leukocyte Telomere Length ◽  
Nucleotide Polymorphisms ◽  
Individual Snps ◽  
Increased Risk ◽  
Weighted Genetic Risk Score

Background: Leukocyte telomere length (LTL) has been associated with the risks of several cancers in observational studies. Mendelian randomization (MR) studies, using genetic variants as instrumental variables, have also shown associations of genetically predicted LTL with cancer risks. In this study, we performed the first MR analysis on soft tissue sarcoma (STS) to investigate the causal relationship between LTL and the risk of STS. Methods: Genotypes from eleven LTL-associated single nucleotide polymorphisms (SNPs) in 821 STS cases and 851 cancer-free controls were aggregated into a weighted genetic risk score (GRS) to predict LTL. Multivariate logistic regression was used to assess the association of STS risk with individual SNPs and aggregated GRS. Results: Four SNPs displayed evidence for an individual association between long LTL-conferring allele and increased STS risk: rs7675998 (odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.02–1.43), rs9420907 (OR = 1.31, 95% CI = 1.08–1.59), rs8105767 (OR = 1.18, 95% CI = 1.02–1.37), and rs412658 (OR = 1.18, 95% CI = 1.02–1.36). Moreover, longer genetically predicted LTL, calculated as GRS, was strongly associated with an increased risk of STS (OR = 1.44, 95% CI = 1.18–1.75, p < 0.001), and there was a significant dose-response association (p for trend <0.001 in tertile and quartile analyses). The association of longer LTL with higher STS risk was more evident in women than in men. In stratified analyses by major STS subtypes, longer LTL was significantly associated with higher risks of leiomyosarcoma and gastrointestinal stromal tumors. Conclusions: Longer LTL is associated with increased risks of STS.

scholarly journals Leukocyte telomere length and amyotrophic lateral sclerosis: a Mendelian randomization study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Kailin Xia ◽  
Linjing Zhang ◽  
Gan Zhang ◽  
Yajun Wang ◽  
Tao Huang ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Telomere Length ◽  
Causal Relationship ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
Genome Wide Association Studies ◽  
Leukocyte Telomere Length ◽  
Weighted Median ◽  
Lateral Sclerosis

Abstract Background Observational studies have suggested that telomere length is associated with amyotrophic lateral sclerosis (ALS). However, whether this association is causal remains unclear. In this study, we aimed to explore the causal relationship between leukocyte telomere length (LTL) and ALS by a two-sample Mendelian randomization (MR) approach. Single-nucleotide polymorphisms (SNPs) for LTL were identified through high-quality genome-wide association studies (GWASs). The ALS GWAS summary data (20,806 cases; 59,804 controls) with largest sample size to date was obtained. We adopted the inverse variance weighted (IVW) method to examine the effect of LTL on ALS and used the weighted median method, simple median method, MR Egger method and MR-PRESSO method to perform sensitivity analyses. Results We found that genetically determined increased LTL was inversely associated with the risk of ALS (odds ratio (OR) = 0.846, 95% confidence interval (CI): 0.744–0.962, P = 0.011), which was mainly driven by rs940209 in the OBFC1 gene, suggesting a potential effect of OBFC1 on ALS. The results were further confirmed by sensitivity analysis with the MR Egger method (OR = 0.647, 95% CI = 0.447–0.936, P = 0.050). Analyses by the weighted median method (OR = 0.893, P = 0.201) and simple median method (OR = 0.935, P = 0.535) also showed a similar trend. The MR Egger analysis did not suggest directional pleiotropy, with an intercept of 0.025 (P = 0.168). Neither the influence of instrumental outliers nor heterogeneity was found. Conclusions Our results suggest that genetically predicted increased LTL has a causal relationship with a lower risk of ALS. Protecting against telomere loss may be of great importance in the prevention and treatment of ALS.

scholarly journals Association between telomere length in peripheral blood leukocytes and risk of ischemic stroke in a Han Chinese population: a linear and non-linear Mendelian randomization analysis

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Weijie Cao ◽  
Deqiang Zheng ◽  
Jie Zhang ◽  
Anxin Wang ◽  
Di Liu ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Telomere Length ◽  
Maximum Likelihood Method ◽  
Mendelian Randomization ◽  
Estimation Method ◽  
Likelihood Method ◽  
Leukocyte Telomere Length ◽  
Linear Effect ◽  
Inverse Variance ◽  
Non Linear

Abstract Background Many contradictory conclusions pertaining to the telomere length in peripheral leukocyte chromosomes as a potential biomarker for ischemic stroke (IS) risk have been reported by the various observational studies in previous years. This study aims to investigate whether the leukocyte telomere length is associated with an increased IS risk or not, based on the Mendelian randomization (MR) approach. Methods Based on the NHGRI-EBI GWAS Catalog database, the Chinese online genetic database as well as the previous published studies, twelve single nucleotide polymorphisms (SNPs) with minor allele frequency ≥ 0.05 were selected and the leukocyte telomere length was measured in 431 first-ever IS patients and 304 healthy controls (quantitative polymerase chain reaction). To explore linear and non-linear effect of telomere length on the IS risk, we preformed the linear MR analysis (the inverse-variance weighted method, the maximum likelihood method, and the mode-based estimation method), and the non-linear MR analysis (semiparametric method with three tests for non-linearity, including the quadratic test, Cochran’s Q test, and the fractional polynomial test). Results Two verified SNPs (rs11125529 and rs412658) were chosen as instrumental variables. In linear MR analysis, the adjusted odds ratios and 95% confidence intervals of IS for genetically predicted telomere lengths, based on the two SNPs, were 1.312 (0.979 to 1.759), 1.326 (0.932 to 1.888) and 1.226 (0.844 to 1.781) for the inverse-variance weighted method, the maximum likelihood method, and the mode-based estimation method, respectively. Three tests for nonlinearity failed to reject the null exactly, indicating that the relationship between telomere length and IS risk is unlikely to be non-linear. Conclusion This MR study based on individual data does not provide strong evidence for a positive linear or non-linear effect of telomere length on the IS risk.

scholarly journals Predicted Leukocyte Telomere Length and Risk of Myeloid Neoplasms

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1335-1335
Author(s):  
Jenny Poynter ◽  
Spencer Kelley ◽  
Marina Marcato ◽  
Erica Langer ◽  
Anthony J Hooten ◽  
...  
Keyword(s):  
Telomere Length ◽  
Myeloid Leukemia ◽  
Mendelian Randomization ◽  
Conflicts Of Interest ◽  
Case Control ◽  
Leukocyte Telomere Length ◽  
Case Control Studies ◽  
Myeloid Malignancy ◽  
Individual Snps ◽  
The Individual

Background Maintenance of telomere length has long been established to play a role in the biology of cancer, and several lines of evidence suggest that it may be especially important in myeloid malignancy. Measuring leukocyte telomere length (LTL) directly in case control studies is problematic because telomere length is likely to be influenced by the disease process. Recent studies have led to the identification of a robust genetic predictor of LTL, which we have used to compare differences in predicted telomere length in case control studies of myeloid leukemia and myelodysplastic syndromes (MDS) using Mendelian randomization (MR). MR is a method used to measure the association between a trait (e.g. telomere length) and an outcome (e.g. myeloid malignancy) that can't be measured directly by utilizing genetic variants known to be associated with the trait as instrumental variables. The use of genetic predictors of telomere length reduces the possibility that the association is explained by reverse causation and confounding likely to be relevant in case-control studies where telomere length is measured directly because genotypes in the general population should be randomly distributed. Additionally, predicted telomere length has the added advantage of representing telomere length over the lifetime of the individual while measuring LTL directly will represent only one time point in an individual's life. Methods Myeloid leukemia (AML and CML) and MDS cases were identified by rapid case ascertainment through the Minnesota Cancer Surveillance System (MCSS). Centralized pathology and cytogenetics reviews were conducted to confirm diagnosis and classify by subtypes. Controls were identified through the Minnesota State driver's license/identification card list. We used the Sequenom platform to genotype seven SNPs that were validated predictors of LTL in a recently published meta-analysis. We estimated associations between individual SNPs and myeloid malignancy using multivariable logistic regression. Mendelian randomization was used to evaluate the association between predicted LTL and risk of myeloid malignancy. Results We included 253 AML cases, 353 MDS cases, 145 CML cases, and 1,042 controls. We observed a significant association between longer predicted telomere length and AML in analyses adjusted for sex and age (OR 4.82 per additional kilobase of average telomere length, 95% CI 1.32-17.63). The individual SNP analyses suggest that the association is largely driven by rs10936599, located in TERC (OR 1.47 per allele, 95% CI 1.14-1.90; Figure). We did not observe statistically significant associations between predicted LTL and MDS or CML. Discussion In this analysis of predicted telomere length and myeloid malignancy, we identified a significant association between longer predicted leukocyte telomere length and AML. In contrast, no significant association was observed for MDS or CML although we did observe an elevated OR for longer predicted telomere length and MDS that did not reach statistical significance. Figure Disclosures No relevant conflicts of interest to declare.

scholarly journals Leukocyte Telomere Length and Amyotrophic Lateral Sclerosis: A Mendelian Randomization Study

2021 ◽  
Author(s):  
Kailin Xia ◽  
Linjing Zhang ◽  
Gan Zhang ◽  
Yajun Wang ◽  
Tao Huang ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Telomere Length ◽  
Causal Relationship ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
Genome Wide Association Studies ◽  
Leukocyte Telomere Length ◽  
Weighted Median ◽  
Lateral Sclerosis

Abstract Observational studies have suggested that telomere length is associated with amyotrophic lateral sclerosis (ALS). However, it remains unclear whether this association is causal. We employed a two-sample Mendelian randomization (MR) approach to explore the causal relationship between leukocyte telomere length (LTL) and ALS based on the most cited and most recent and largest LTL genome-wide association studies (GWASs) that measured LTL with the Southern blot method (n=9190) and ALS GWAS summary data (n=80,610). We adopted the inverse variance weighted (IVW) method to examine the effect of LTL on ALS and used the weighted median method, simple median method, MR Egger method and MR PRESSO method to perform sensitivity analyses. We found that genetically determined longer LTL was inversely associated with the risk of ALS (OR=0.846, 95% CI: 0.744-0.962, P=0.011), which was mainly driven by rs940209 in the OBFC1 gene, suggesting a potential effect of OBFC1 on ALS. In sensitivity analyses, that was confirmed in MR Egger method (OR=0.647,95% CI=0.447-0.936, P=0.050), and a similar trend was shown with the weighted median method (OR=0.893, P=0.201) and simple median method (OR=0.935 P=0.535). The MR Egger analyses did not suggest directional pleiotropy, showing an intercept of 0.025 (P=0.168). Neither the influence of instrumental outliers nor heterogeneity was found. Our results suggest that genetically predicted longer LTL has a causal relationship with a lower risk of ALS and underscore the importance of protecting against telomere loss in ALS.

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