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

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.

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

10.21203/rs.3.rs-522773/v2 ◽

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.

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

10.21203/rs.3.rs-522773/v1 ◽

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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Assessing the role of blood pressure in amyotrophic lateral sclerosis: a Mendelian randomization study

10.21203/rs.3.rs-885601/v1 ◽

2021 ◽

Author(s):

Kailin Xia ◽

Linjing Zhang ◽

Lu Tang ◽

Tao Huang ◽

Dongsheng Fan

Keyword(s):

Blood Pressure ◽

Amyotrophic Lateral Sclerosis ◽

Protective Factor ◽

Mendelian Randomization ◽

Association Studies ◽

Sensitivity Analyses ◽

Genome Wide Association Studies ◽

Inverse Variance ◽

High Level ◽

Lateral Sclerosis

Abstract Background Observational studies have suggested a close but controversial relationship between blood pressure (BP) and amyotrophic lateral sclerosis (ALS). However, it remains unclear whether this association is causal. The authors employed a bidirectional two-sample Mendelian randomization (MR) approach to investigate whether there is a causal relationship between BP and ALS. Genetic proxies for systolic blood pressure (SBP), diastolic blood pressure (DBP), antihypertension drugs (AHDs), ALS, and their corresponding genome-wide association studies (GWAS) summary datasets were obtained from the updated largest studies. Inverse variance weighted (IVW) method was adopted as the main approach to examine the effect of BP on ALS and four other MR methods for sensitivity analyses. To exclude the interference between SBP and DBP, multivariable MR was used. Results We found that genetically determined increased DBP was a protective factor for ALS (OR = 0.978, 95% CI 0.960–0.996, P = 0.017), and increased SBP was an independent risk factor for ALS (OR = 1.014, 95% CI 1.003–1.025, P = 0.015). The high level of targeted protein of Calcium channel blocker (CCB) showed a causative relationship with ALS (OR = 0.985, 95% CI 0.971-1.000, P = 0.049). No evidence was revealed that ALS caused results change of BP measurements. Conclusions This study demonstrated that an increase in DBP is a protective factor for ALS, and increased SBP is independently risk for ALS, which may be related to sympathetic excitability. Blood pressure management is important in ALS, in which CCB may be a promising candidate.

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Causal Effects of Blood Lipids on Amyotrophic Lateral Sclerosis: A Mendelian Randomization Study

10.1101/447581 ◽

2018 ◽

Author(s):

Ping Zeng ◽

Xiang Zhou

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Causal Relationship ◽

Mendelian Randomization ◽

East Asian ◽

Density Lipoprotein ◽

Causal Effects ◽

Sensitivity Analyses ◽

Genome Wide Association Studies ◽

Asian Populations ◽

Lateral Sclerosis

AbstractAmyotrophic lateral sclerosis (ALS) is a late-onset fatal neurodegenerative disorder that is predicted to increase across the globe by ~70% in the following decades. Understanding the disease causal mechanism underlying ALS and identifying modifiable risks factors for ALS hold the key for the development of effective preventative and treatment strategies. Here, we investigate the causal effects of four blood lipid traits that include high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC), and triglycerides (TG) on the risk of ALS. By leveraging instrument variables from multiple large-scale genome-wide association studies in both European and East Asian populations, we carry out one of the largest and most comprehensive Mendelian randomization analyses performed to date on the causal relationship between lipids and ALS. Among the four lipids, we found that only LDL is causally associated with ALS and that higher LDL level increases the risk of ALS in both the European and East Asian populations. Specifically, the odds ratio of ALS per one standard deviation (i.e. 39.0 mg/dL) increase of LDL is estimated to be 1.14 (95% CI 1.05 - 1.24, p = 1.38E-3) in the European and population and 1.06 (95% CI 1.00 - 1.12, p = 0.044) in the East Asian population. The identified causal relationship between LDL and ALS is robust with respect to the choice of statistical methods and is validated through extensive sensitivity analyses that guard against various model assumption violations. Our study provides important evidence supporting the causal role of higher LDL on increasing the risk of ALS, paving ways for the development of preventative strategies for reducing the disease burden of ALS across multiple nations.

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Association of 25 hydroxyvitamin D concentration with risk of COVID-19: a Mendelian randomization study

10.1101/2020.08.09.20171280 ◽

2020 ◽

Author(s):

Di Liu ◽

Qiuyue Tian ◽

Jie Zhang ◽

Haifeng Hou ◽

Wei Wang ◽

...

Keyword(s):

Causal Relationship ◽

Mendelian Randomization ◽

Association Studies ◽

Sensitivity Analyses ◽

Genome Wide Association Studies ◽

Causal Association ◽

Hydroxyvitamin D ◽

Increased Risk ◽

25Ohd Concentration ◽

25 Hydroxyvitamin D

Background In observational studies, 25 hydroxyvitamin D (25OHD) concentration has been associated with an increased risk of Coronavirus disease 2019 (COVID-19). However, it remains unclear whether this association is causal. Methods We performed a two-sample Mendelian randomization (MR) to explore the causal relationship between 25OHD concentration and COVID-19, using summary data from the genome-wide association studies (GWASs) and using 25OHD concentration-related SNPs as instrumental variables (IVs). Results MR analysis did not show any evidence of a causal association of 25OHD concentration with COVID-19 susceptibility and severity (odds ratio [OR]=1.136, 95% confidence interval [CI] 0.988-1.306, P=0.074; OR=0.889, 95% CI 0.549-1.439, P=0.632). Sensitivity analyses using different instruments and statistical models yielded similar findings, suggesting the robustness of the causal association. No obvious pleiotropy bias and heterogeneity were observed. Conclusion The MR analysis showed that there might be no linear causal relationship of 25OHD concentration with COVID-19 susceptibility and severity.

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Genetically Predicted Circulating Concentrations of Micronutrients and Risk of Amyotrophic Lateral Sclerosis: A Mendelian Randomization Study

Frontiers in Genetics ◽

10.3389/fgene.2021.811699 ◽

2022 ◽

Vol 12 ◽

Author(s):

Changqing Mu ◽

Yating Zhao ◽

Chen Han ◽

Dandan Tian ◽

Na Guo ◽

...

Keyword(s):

Amyotrophic Lateral Sclerosis ◽

Large Scale ◽

Mendelian Randomization ◽

Association Studies ◽

Genome Wide Association Studies ◽

Nucleotide Polymorphisms ◽

Inverse Variance ◽

Effective Role ◽

Copper Zinc ◽

Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive and devastating neurodegenerative disease with increasing incidence and high mortality, resulting in a considerable socio-economic burden. Till now, plenty of studies have explored the potential relationship between circulating levels of various micronutrients and ALS risk. However, the observations remain equivocal and controversial. Thus, we conducted a two-sample Mendelian randomization (MR) study to investigate the causality between circulating concentrations of 9 micronutrients, including retinol, folate acid, vitamin B12, B6 and C, calcium, copper, zinc as well as magnesium, and ALS susceptibility. In our analysis, several single nucleotide polymorphisms were collected as instrumental variables from large-scale genome-wide association studies of these 9 micronutrients. Then, inverse variance weighted (IVW) approach as well as alternative MR-Egger regression, weighted median and MR-pleiotropy residual sum and outlier (MR-PRESSO) analyses were performed to evaluate causal estimates. The results from IVW analysis showed that there was no causal relationship of 9 micronutrients with ALS risk. Meanwhile, the three complementary approaches obtained similar results. Thus, our findings indicated that supplementation of these 9 micronutrients may not play a clinically effective role in preventing the occurrence of ALS.

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Association between premorbid body mass index and amyotrophic lateral sclerosis: causal inference through genetic approaches

10.1101/526186 ◽

2019 ◽

Cited By ~ 3

Author(s):

Ping Zeng ◽

Xinghao Yu ◽

Haibo Xu

Keyword(s):

Body Mass Index ◽

Amyotrophic Lateral Sclerosis ◽

Causal Relationship ◽

Body Mass ◽

European Population ◽

Sensitivity Analyses ◽

Genome Wide Association Studies ◽

Inverse Association ◽

Standard Deviation Increase ◽

Lateral Sclerosis

Background: Inverse association between premorbid body mass index (BMI) and amyotrophic lateral sclerosis (ALS) has been discovered in observational studies; however, whether this association is causal remains largely unknown. Methods: We employed a two-sample Mendelian randomization approach to evaluate the causal relationship of genetically increased BMI with the risk of ALS. The analyses were implemented using summary statistics obtained for the independent instruments identified from large-scale genome-wide association studies of BMI (up to ~770,000 individuals) and ALS (up to ~81,000 individuals). The causal relationship between BMI and ALS was estimated using inverse-variance weighted methods and was further validated through extensive complementary and sensitivity analyses. Findings: Using 1,031 instruments strongly related to BMI, the causal effect of per one standard deviation increase of BMI was estimated to be 1.04 (95% CI 0.97~1.11, p=0.275) in the European population. The null association between BMI and ALS discovered in the European population also held in the East Asian population and was robust against various modeling assumptions and outlier biases. Additionally, the Egger-regression and MR-PRESSO ruled out the possibility of horizontal pleiotropic effects of instruments. Interpretation: Our results do not support the causal role of genetically increased or decreased BMI on the risk of ALS.

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Causal association of adipokines with osteoarthritis: a Mendelian randomization study

Rheumatology ◽

10.1093/rheumatology/keaa719 ◽

2020 ◽

Author(s):

Jiayao Fan ◽

Jiahao Zhu ◽

Lingling Sun ◽

Yasong Li ◽

Tianle Wang ◽

...

Keyword(s):

Mendelian Randomization ◽

Association Studies ◽

Genome Wide Association ◽

Sensitivity Analyses ◽

European Ancestry ◽

Genome Wide Association Studies ◽

Knee Oa ◽

Genome Wide ◽

A Genome ◽

Weighted Median

Abstract Objective This two-sample Mendelian randomization study aimed to delve into the effects of genetically predicted adipokine levels on OA. Methods Summary statistic data for OA originated from a meta-analysis of a genome-wide association study with an overall 50 508 subjects of European ancestry. Publicly available summary data from four genome-wide association studies were exploited to respectively identify instrumental variables of adiponectin, leptin, resistin, chemerin and retinol-blinding protein 4. Subsequently, Mendelian randomization analyses were conducted with inverse variance weighted (IVW), weighted median and Mendelian randomization-Egger regression. Furthermore, sensitivity analyses were then conducted to assess the robustness of our results. Results The positive causality between genetically predicted leptin level and risk of total OA was indicated by IVW [odds ratio (OR): 2.40, 95% CI: 1.13–5.09] and weighted median (OR: 2.94, 95% CI: 1.23–6.99). In subgroup analyses, evidence of potential harmful effects of higher level of adiponectin (OR: 1.28, 95% CI: 1.01–1.61 using IVW), leptin (OR: 3.44, 95% CI: 1.18–10.03 using IVW) and resistin (OR: 1.18, 95% CI: 1.03–1.36 using IVW) on risk of knee OA were acquired. However, the mentioned effects on risk of hip OA were not statistically significant. Slight evidence was identified supporting causality of chemerin and retinol-blinding protein 4 for OA. The findings of this study were verified by the results from sensitivity analysis. Conclusions An association between genetically predicted leptin level and risk of total OA was identified. Furthermore, association of genetically predicted levels of adiponectin, leptin and resistin with risk of knee OA were reported.

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Genetic Evidence That Carbohydrate-Stimulated Insulin Secretion Leads to Obesity

Clinical Chemistry ◽

10.1373/clinchem.2017.280727 ◽

2018 ◽

Vol 64 (1) ◽

pp. 192-200 ◽

Cited By ~ 31

Author(s):

Christina M Astley ◽

Jennifer N Todd ◽

Rany M Salem ◽

Sailaja Vedantam ◽

Cara B Ebbeling ◽

...

Keyword(s):

Body Weight ◽

Insulin Secretion ◽

Causal Relationship ◽

Mendelian Randomization ◽

Association Studies ◽

Sensitivity Analyses ◽

European Ancestry ◽

Oral Glucose ◽

Genome Wide Association Studies ◽

Genetically Determined

Abstract BACKGROUND A fundamental precept of the carbohydrate–insulin model of obesity is that insulin secretion drives weight gain. However, fasting hyperinsulinemia can also be driven by obesity-induced insulin resistance. We used genetic variation to isolate and estimate the potentially causal effect of insulin secretion on body weight. METHODS Genetic instruments of variation of insulin secretion [assessed as insulin concentration 30 min after oral glucose (insulin-30)] were used to estimate the causal relationship between increased insulin secretion and body mass index (BMI), using bidirectional Mendelian randomization analysis of genome-wide association studies. Data sources included summary results from the largest published metaanalyses of predominantly European ancestry for insulin secretion (n = 26037) and BMI (n = 322154), as well as individual-level data from the UK Biobank (n = 138541). Data from the Cardiology and Metabolic Patient Cohort study at Massachusetts General Hospital (n = 1675) were used to validate genetic associations with insulin secretion and to test the observational association of insulin secretion and BMI. RESULTS Higher genetically determined insulin-30 was strongly associated with higher BMI (β = 0.098, P = 2.2 × 10−21), consistent with a causal role in obesity. Similar positive associations were noted in sensitivity analyses using other genetic variants as instrumental variables. By contrast, higher genetically determined BMI was not associated with insulin-30. CONCLUSIONS Mendelian randomization analyses provide evidence for a causal relationship of glucose-stimulated insulin secretion on body weight, consistent with the carbohydrate–insulin model of obesity.

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Sleep, major depressive disorder, and Alzheimer disease

Neurology ◽

10.1212/wnl.0000000000010463 ◽

2020 ◽

Vol 95 (14) ◽

pp. e1963-e1970 ◽

Cited By ~ 1

Author(s):

Jian Huang ◽

Verena Zuber ◽

Paul M. Matthews ◽

Paul Elliott ◽

Joanna Tzoulaki ◽

...

Keyword(s):

Major Depressive Disorder ◽

Alzheimer Disease ◽

Depressive Disorder ◽

Causal Relationship ◽

Mendelian Randomization ◽

Association Studies ◽

Sensitivity Analyses ◽

Genome Wide Association Studies ◽

Sleep Patterns ◽

Major Depressive

ObjectiveTo explore the causal relationships between sleep, major depressive disorder (MDD), and Alzheimer disease (AD).MethodsWe conducted bidirectional 2-sample Mendelian randomization analyses. Genetic associations were obtained from the largest genome-wide association studies currently available in UK Biobank (n = 446,118), Psychiatric Genomics Consortium (n = 18,759), and International Genomics of Alzheimer's Project (n = 63,926). We used the inverse variance–weighted Mendelian randomization method to estimate causal effects and weighted median and Mendelian randomization–Egger for sensitivity analyses to test for pleiotropic effects.ResultsWe found that higher risk of AD was significantly associated with being a “morning person” (odds ratio [OR] 1.01, p = 0.001), shorter sleep duration (self-reported: β = −0.006, p = 1.9 × 10−4; accelerometer based: β = −0.015, p = 6.9 × 10−5), less likely to report long sleep (β = −0.003, p = 7.3 × 10−7), earlier timing of the least active 5 hours (β = −0.024, p = 1.7 × 10−13), and a smaller number of sleep episodes (β = −0.025, p = 5.7 × 10−14) after adjustment for multiple comparisons. We also found that higher risk of AD was associated with lower risk of insomnia (OR 0.99, p = 7 × 10−13). However, we did not find evidence that these abnormal sleep patterns were causally related to AD or for a significant causal relationship between MDD and risk of AD.ConclusionWe found that AD may causally influence sleep patterns. However, we did not find evidence supporting a causal role of disturbed sleep patterns for AD or evidence for a causal relationship between MDD and AD.

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