Causal relationships between blood lipids and depression phenotypes: A Mendelian randomization analysis

2018 ◽  
Author(s):  
Hon-Cheong So ◽  
Carlos Kwan-long Chau ◽  
Yu-ying Cheng ◽  
Pak C. Sham
Keyword(s):  
Causal Relationship ◽  
Large Scale ◽  
Blood Lipids ◽  
Mendelian Randomization ◽  
Blood Lipid ◽  
Lipid Lowering ◽  
Causal Relationships ◽  
Low Mood ◽  
Moderate Evidence ◽  
Mechanistic Basis

AbstractBackgroundThe etiology of depression remains poorly understood. Changes in blood lipid levels were reported to be associated with depression and suicide, however study findings were mixed.MethodsWe performed a two-sample Mendelian randomization (MR) analysis to investigate the causal relationship between blood lipids and depression phenotypes, based on large-scale GWAS summary statistics (N=188,577/480,359 for lipid/depression traits respectively). Five depression-related phenotypes were included, namely major depressive disorder (MDD; from PGC), depressive symptoms (DS; from SSGAC), longest duration and number of episodes of low mood, and history of deliberate self-harm (DSH)/suicide (from UK Biobank). MR was conducted with inverse-variance weighted (MR-IVW), Egger and Generalized Summary-data-based MR(GSMR) methods.ResultsThere was consistent evidence that triglyceride (TG) is causally associated with DS (MR-IVW beta for one-SD increase in TG=0.0346, 95% CI=0.0114-0.0578), supported by MR-IVW and GSMR and multiple r2 clumping thresholds. We also observed relatively consistent associations of TG with DSH/suicide (MR-Egger OR= 2.514, CI: 1.579-4.003). There was moderate evidence for positive associations of TG with MDD and the number of episodes of low mood. For HDL-c, we observed moderate evidence for causal associations with DS and MDD. LDL-c and TC did not show robust causal relationships with depression phenotypes, except for weak evidence that LDL-c is inversely related to DSH/suicide. We did not detect significant associations when depression phenotypes were treated as exposures.ConclusionsThis study provides evidence to a causal relationship between TG, and to a lesser extent, altered cholesterol levels with depression phenotypes. Further studies on its mechanistic basis and the effects of lipid-lowering therapies are warranted.

Causal relationships between blood lipids and depression phenotypes: a Mendelian randomisation analysis

2020 ◽  
pp. 1-13 ◽  
Author(s):  
Hon-Cheong So ◽  
Carlos Kwan-long Chau ◽  
Yu-ying Cheng ◽  
Pak C. Sham
Keyword(s):  
Causal Relationship ◽  
Large Scale ◽  
Blood Lipids ◽  
Blood Lipid ◽  
Lipid Lowering ◽  
Mendelian Randomisation ◽  
Causal Relationships ◽  
Low Mood ◽  
Moderate Evidence ◽  
Mechanistic Basis

Abstract Background The etiology of depression remains poorly understood. Changes in blood lipid levels were reported to be associated with depression and suicide, however study findings were mixed. Methods We performed a two-sample Mendelian randomisation (MR) analysis to investigate the causal relationship between blood lipids and depression phenotypes, based on large-scale GWAS summary statistics (N = 188 577/480 359 for lipid/depression traits respectively). Five depression-related phenotypes were included, namely major depression (MD; from PGC), depressive symptoms (DS; from SSGAC), longest duration and number of episodes of low mood, and history of deliberate self-harm (DSH)/suicide (from UK Biobank). MR was conducted with inverse-variance weighted (MR-IVW), Egger and Generalised Summary-data-based MR (GSMR) methods. Results There was consistent evidence that triglyceride (TG) is causally associated with DS (MR-IVW β for one-s.d. increase in TG = 0.0346, 95% CI 0.0114–0.0578), supported by MR-IVW and GSMR and multiple r2 clumping thresholds. We also observed relatively consistent associations of TG with DSH/suicide (MR-Egger OR = 2.514, CI 1.579–4.003). There was moderate evidence for positive associations of TG with MD and the number of episodes of low mood. For HDL-c, we observed moderate evidence for causal associations with DS and MD. LDL-c and TC did not show robust causal relationships with depression phenotypes, except for weak evidence that LDL-c is inversely related to DSH/suicide. We did not detect significant associations when depression phenotypes were treated as exposures. Conclusions This study provides evidence to a causal relationship between TG, and to a lesser extent, altered cholesterol levels with depression phenotypes. Further studies on its mechanistic basis and the effects of lipid-lowering therapies are warranted.

scholarly journals Using a Two-Sample Mendelian Randomization Method in Assessing the Causal Relationships Between Human Blood Metabolites and Heart Failure

2021 ◽  
Vol 8 ◽  
Author(s):  
Zixian Wang ◽  
Shiyu Chen ◽  
Qian Zhu ◽  
Yonglin Wu ◽  
Guifeng Xu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Human Blood ◽  
Large Scale ◽  
Genome Wide Association Study ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Meta Analysis ◽  
Sensitivity Analyses ◽  
Blood Metabolites ◽  
Causal Relationships

Background: Heart failure (HF) is the main cause of morbidity and mortality worldwide, and metabolic dysfunction is an important factor related to HF pathogenesis and development. However, the causal effect of blood metabolites on HF remains unclear.Objectives: Our chief aim is to investigate the causal relationships between human blood metabolites and HF risk.Methods: We used an unbiased two-sample Mendelian randomization (MR) approach to assess the causal relationships between 486 human blood metabolites and HF risk. Exposure information was obtained from Sample 1, which is the largest metabolome-based genome-wide association study (mGWAS) data containing 7,824 Europeans. Outcome information was obtained from Sample 2, which is based on the results of a large-scale GWAS meta-analysis of HF and contains 47,309 cases and 930,014 controls of Europeans. The inverse variance weighted (IVW) model was used as the primary two-sample MR analysis method and followed the sensitivity analyses, including heterogeneity test, horizontal pleiotropy test, and leave-one-out analysis.Results: We observed that 11 known metabolites were potentially related to the risk of HF after using the IVW method (P < 0.05). After adding another four MR models and performing sensitivity analyses, we found a 1-SD increase in the xenobiotics 4-vinylphenol sulfate was associated with ~22% higher risk of HF (OR [95%CI], 1.22 [1.07–1.38]).Conclusions: We revealed that the 4-vinylphenol sulfate may nominally increase the risk of HF by 22% after using a two-sample MR approach. Our findings may provide novel insights into the pathogenesis underlying HF and novel strategies for HF prevention.

scholarly journals Causal Association Between Heart Failure and Alzheimer’s Disease: A Two-Sample Bidirectional Mendelian Randomization Study

2022 ◽  
Vol 12 ◽  
Author(s):  
Chenglin Duan ◽  
Jingjing Shi ◽  
Guozhen Yuan ◽  
Xintian Shou ◽  
Ting Chen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Sensitivity Analysis ◽  
Causal Relationship ◽  
Observational Studies ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Causal Relationships ◽  
Simple Mode

Background: Traditional observational studies have demonstrated an association between heart failure and Alzheimer’s disease. The strengths of observational studies lie in their speed of implementation, cost, and applicability to rare diseases. However, observational studies have several limitations, such as uncontrollable confounders. Therefore, we employed Mendelian randomization of genetic variants to evaluate the causal relationships existing between AD and HF, which can avoid these limitations.Materials and Methods: A two-sample bidirectional MR analysis was employed. All datasets were results from the UK’s Medical Research Council Integrative Epidemiology Unit genome-wide association study database, and we conducted a series of control steps to select the most suitable single-nucleotide polymorphisms for MR analysis, for which five primary methods are offered. We reversed the functions of exposure and outcomes to explore the causal direction of HF and AD. Sensitivity analysis was used to conduct several tests to avoid heterogeneity and pleiotropic bias in the MR results.Results: Our MR studies did not support a meaningful causal relationship between AD on HF (MR-Egger, p = 0.634 > 0.05; weighted median (WM), p = 0.337 > 0.05; inverse variance weighted (IVW), p = 0.471 > 0.05; simple mode, p = 0.454 > 0.05; weighted mode, p = 0.401 > 0.05). At the same time, we did not find a significant causal relationship between HF and AD with four of the methods (MR-Egger, p = 0.195 > 0.05; IVW, p = 0.0879 > 0.05; simple mode, p = 0.170 > 0.05; weighted mode, p = 0.110 > 0.05), but the WM method indicated a significant effect of HF on AD (p = 0.025 < 0.05). Because the statistical powers of IVW and MR-Egger are more than that of WM, we think that there is no causal effect of HF on AD. Sensitivity analysis and horizontal pleiotropy were not detected in the MR analysis.Conclusion: Our results did not provide significant evidence indicating any causal relationships between HF and AD in the European population. Therefore, more large-scale datasets or datasets related to similar factors are expected for further MR analysis.

scholarly journals Inferring Causal Direction Between Two Traits in the Presence of Horizontal Pleiotropy with GWAS Summary Data

2020 ◽  
Author(s):  
Haoran Xue ◽  
Wei Pan
Keyword(s):  
Causal Relationship ◽  
Statistical Power ◽  
Goodness Of Fit ◽  
Mendelian Randomization ◽  
Density Lipoprotein ◽  
Superior Performance ◽  
Causal Relationships ◽  
Goodness Of Fit Tests ◽  
Causal Direction ◽  
Instrument Variable

AbstractOrienting the causal relationship between pairs of traits is a fundamental task in scientific research with significant implications in practice, such as in prioritizing molecular targets and modifiable risk factors for developing therapeutic and interventional strategies for complex diseases. A recent method, called Steiger’s method, using a single SNP as an instrument variable (IV) in the framework of Mendelian randomization (MR), has since been widely applied. We report the following new contributions. First, we propose a single SNP-based alternative, overcoming a severe limitation of Steiger’s method in simply assuming, instead of inferring, the existence of a causal relationship. We also clarify a condition necessary for the validity of the methods in the presence of hidden confounding. Second, to improve statistical power, we propose combining the results from multiple, and possibly correlated, SNPs. as multiple instruments. Third, we develop three goodness-of-fit tests to check modeling assumptions, including those required for valid IVs. Fourth, by relaxing one of the three IV assumptions in MR, we propose methods, including one Egger regression-like approach and its multivariable version (analogous to multivariable MR), to account for horizontal pleiotropy of the SNPs/IVs, which is often unavoidable in practice. All our methods can simultaneously infer both the existence and (if so) the direction of a causal relationship, largely expanding their applicability over that of Steiger’s method. Although we focus on uni-directional causal relationships, we also briefly discuss an extension to bi-directional relationships. Through extensive simulations and an application to infer the causal directions between low density lipoprotein (LDL) cholesterol, or high density lipoprotein (HDL) cholesterol, and coronary artery disease (CAD), we demonstrate the superior performance and advantage of our proposed methods over Steiger’s method and bi-directional MR. In particular, after accounting for horizontal pleiotropy, our method confirmed the well known causal direction from LDL to CAD, while other methods, including bi-directional MR, failed.Author SummaryIn spite of its importance, due to technical challenges, orienting causal relationships between pairs of traits has been largely under-studied. Mendelian randomization (MR) Steiger’s method has become increasingly used in the last two years. Here we point out several limitations with MR Steiger’s method and propose alternative approaches. First, MR Steiger’s method is based on using only one single SNP as the instrument variable (IV), for which we propose a correlation ratio-based method, called Causal Direction-Ratio, or simply CD-Ratio. An advantage of CD-Ratio is its inference of both the existence and (if so) the direction of a causal relationship, in contrast to MR Steiger’s prior assumption of the existence and its poor performance if the assumption is violated. Furthermore, CD-Ratio can be extended to combine the results from multiple, possibly correlated, SNPs with improved statistical power. Second, we propose two methods, called CD-Egger and CD-GLS, for multiple and possibly correlated SNPs while allowing horizontal pleiotropy. Third, we propose three goodness-of-fit tests to check modeling assumptions for the three proposed methods. Finally, we introduce multivariable CD-Egger, analogous to multivariable MR, as a more robust approach, and an extension of CD-Ratio to cases with possibly bi-directional causal relationships. Our numerical studies demonstrated superior performance of our proposed methods over MR Steiger and bi-directional MR. Our proposed methods, along with freely available software, are expected to be useful in practice for causal inference.

scholarly journals Positive effects of low LDL-C and statins on bone mineral density: an integrated epidemiological observation analysis and Mendelian Randomization study

2019 ◽  
Author(s):  
Gloria Hoi-Yee Li ◽  
Ching-Lung Cheung ◽  
Philip Chun-Ming Au ◽  
Kathryn Choon-Beng Tan ◽  
Ian Chi-Kei Wong ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Blood Lipids ◽  
Mendelian Randomization ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Blood Lipid ◽  
Nhanes Iii ◽  
Mineral Density ◽  
Positive Effects ◽  
Epidemiological Observation

AbstractBackgroundLow-density lipoprotein cholesterol (LDL-C) is suggested to play a role in osteoporosis but its association with bone metabolism remains unclear. Effects of LDL-C-lowering drugs on bone are also controversial. We aim to determine whether LDL-C is linked causally to BMD and assess the effects of LDL-C-lowering drugs on BMD.MethodsAssociation between blood lipid levels and BMD was examined by epidemiological observation analyses in US representative cohort NHANES III (N=3,638) and Hong Kong Osteoporosis Study (HKOS; N=1,128). Two-sample Mendelian Randomization (MR), employing genetic data from GWAS of blood lipids (N=188,577), total body BMD (TB-BMD) (N=66,628) and estimated BMD (eBMD) (N=142,487), was performed to infer causality between blood lipids and BMD. Genetic proxies for LDL-C-lowering drugs were used to examine the drugs’ effects on BMD.ResultsIn NHANES III cohort, each SD decrease in LDL-C was associated with 0.045 SD increase in femoral neck BMD (95% CI: 0.009 to 0.081; P=0.015). A similar increase in BMD was observed in HKOS at femoral neck and lumbar spine. In MR analysis, decrease in genetically predicted LDL-C was associated with increase in TB-BMD [estimate per SD decrease, 0.038 (95% CI: 0.002 to 0.074); P=0.038] and eBMD [0.076 (0.042 to 0.111); P=1.20×10−5]. Reduction of TB-BMD was causally associated with increased LDL-C [0.035 (0.033 to 0.066); P=0.034]. Statins’ LDL-C-lowering proxies were associated with increased TB-BMD [0.18 (0.044 to 0.316); P=9.600×10−3] and eBMD [0.143 (0.062 to 0.223); P=5.165×10−4].ConclusionsNegative causal association exists between LDL-C level and BMD. Statins’ LDL-C-lowering effect increases BMD, suggesting its protective effect on bone.

scholarly journals Apolipoprotein B underlies the causal relationship of circulating blood lipids with coronary heart disease

2019 ◽  
Author(s):  
Tom G Richardson ◽  
Eleanor Sanderson ◽  
Tom M. Palmer ◽  
Mika Ala-Korpela ◽  
Brian A Ference ◽  
...  
Keyword(s):  
Coronary Heart Disease ◽  
Heart Disease ◽  
Apolipoprotein B ◽  
Blood Lipids ◽  
Ldl Cholesterol ◽  
Mendelian Randomization ◽  
Hdl Cholesterol ◽  
Blood Lipid ◽  
Apolipoprotein A ◽  
Relationship Of

AbstractBackgroundCirculating blood lipids cause coronary heart disease (CHD). However, the precise way in which one or more lipoprotein lipid-related entities account for this relationship remains unclear. We sought to explore the causal relationships of blood lipid traits with risk of CHD using multivariable Mendelian randomization.MethodsWe conducted GWAS of circulating blood lipid traits in UK Biobank (up to n=440,546) for LDL cholesterol, triglycerides and apolipoprotein B to identify lipid-associated SNPs. Using data from CARDIoGRAMplusC4D for CHD (consisting of 60,801 cases and 123,504 controls), we performed univariable and multivariable Mendelian randomization (MR) analyses. Similar analyses were conducted for HDL cholesterol and apolipoprotein A-I.FindingsGWAS identified multiple independent SNPs associated at P<5×10−8 for LDL cholesterol (220), apolipoprotein B (n=255), triglycerides (440), HDL cholesterol (534) and apolipoprotein AI (440). Between 56-93% of SNPs identified for each lipid trait had not been previously reported in large-scale GWAS. Almost half (46%) of these SNPs were associated at P<5×10−8 with more than one lipid related trait. Assessed individually using MR, each of LDL cholesterol (OR 1.66 per 1 standard deviation higher trait; 95%CI: 1.49; 1.86; P=2.4×10−19), triglycerides (OR 1.34; 95%CI: 1.25, 1.44; P=9.1×10−16) and apolipoprotein B (OR 1.73; 95%CI: 1.56, 1.91; P=1.5×10−25) had effect estimates consistent with a higher risk of CHD. In multivariable MR, only apolipoprotein B (OR 1.92; 95%CI: 1.31, 2.81; P=7.5×10−4) retained a robust effect with the estimate for LDL cholesterol (OR 0.85; 95%CI: 0.57; 1.27; P=0.44) reversing and that of triglycerides (OR 1.12; 95%CI: 1.02, 1.23; P=0.01) becoming markedly weaker.Individual MR analyses showed a 1-SD higher HDL-C (OR 0.80; 95%CI: 0.75, 0.86; P=1.7×10−10) and apolipoprotein A-I (OR 0.83; 95%CI: 0.77, 0.89; P=1.0×10−6) to lower the risk of CHD but these effect estimates weakened to include the null on accounting for apolipoprotein B.ConclusionsApolipoprotein B is of fundamental causal relevance in the aetiology of CHD, and underlies the relationship of LDL cholesterol and triglycerides with CHD.

scholarly journals Birthweight, Type 2 Diabetes and Cardiovascular Disease: Addressing the Barker Hypothesis with Mendelian randomization

2017 ◽  
Author(s):  
Daniela Zanetti ◽  
Emmi Tikkanen ◽  
Stefan Gustafsson ◽  
James Rush Priest ◽  
Stephen Burgess ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Type 2 Diabetes ◽  
Cardiovascular Disease ◽  
Causal Relationship ◽  
Mendelian Randomization ◽  
Large Population ◽  
Sensitivity Analyses ◽  
Lipid Lowering ◽  
Barker Hypothesis

AbstractBackgroundLow birthweight (BW) has been associated with a higher risk of hypertension, type 2 diabetes (T2D) and cardiovascular disease (CVD) in epidemiological studies. The Barker hypothesis posits that intrauterine growth restriction resulting in lower BW is causal for these diseases, but causality and mechanisms are difficult to infer from observational studies. Mendelian randomization (MR) is a new tool to address this important question.MethodsWe performed regression analyses to assess associations of self-reported BW with CVD and T2D in 237,631 individuals from the UK Biobank, a large population-based cohort study aged 40-69 years recruited across UK in 2006-2010. Further, we assessed the causal relationship of such associations using the two- sample MR approach, estimating the causal effect by contrasting the SNP effects on the exposure with the SNP effects on the outcome using independent publicly available genome-wide association datasets.ResultsIn the observational analyses, BW showed strong inverse associations with systolic and diastolic blood pressure (β, −0.83 and −0.26; per raw unit in outcomes and SD change in BW; 95% CI, −0.90, −0.75 and −0.31, −0.22, respectively), T2D (odds ratio [OR], 0.83; 95% CI, 0.79, 0.87), lipid-lowering treatment (OR, 0.84; 95% CI, 0.81, 0.86) and CAD (hazard ratio [HR] 0.85; 95% CI, 0.78, 0.94); while the associations with adult body mass index (BMI) and body fat (β, 0.04 and 0.02; per SD change in outcomes and BW; 95% CI, 0.03, 0.04 and 0.01, 0.02, respectively) were positive. The MR analyses indicated inverse causal associations of BW with low density lipoprotein cholesterol, 2-hour glucose, CAD and T2D, and positive causal association with BMI; but no associations with blood pressure. Sensitivity analyses and robust MR methods provided consistent results and indicated no horizontal pleiotropy.ConclusionOur study indicates that lower BW is causally and directly related with increased susceptibility to CAD and T2D in adulthood. This causal relationship is not mediated by adult obesity or hypertension.

scholarly journals Longitudinal trajectories of blood lipid levels in an ageing population sample of Russian Western-Siberian urban population

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260229
Author(s):  
Jaroslav A. Hubacek ◽  
Yuri Nikitin ◽  
Yulia Ragino ◽  
Ekaterina Stakhneva ◽  
Hynek Pikhart ◽  
...  
Keyword(s):  
Blood Lipids ◽  
Population Sample ◽  
Age Groups ◽  
Serum Triglyceride ◽  
Blood Lipid ◽  
Lipid Lowering ◽  
Ageing Population ◽  
Mixed Effect ◽  
Over Time

This study investigated 12-year blood lipid trajectories and whether these trajectories are modified by smoking and lipid lowering treatment in older Russians. To do so, we analysed data on 9,218 Russian West-Siberian Caucasians aged 45–69 years at baseline participating in the international HAPIEE cohort study. Mixed-effect multilevel models were used to estimate individual level lipid trajectories across the baseline and two follow-up examinations (16,445 separate measurements over 12 years). In all age groups, we observed a reduction in serum total cholesterol (TC), LDL-C and non-HDL-C over time even after adjusting for sex, statin treatment, hypertension, diabetes, social factors and mortality (P<0.01). In contrast, serum triglyceride (TG) values increased over time in younger age groups, reached a plateau and decreased in older age groups (> 60 years at baseline). In smokers, TC, LDL-C, non-HDL-C and TG decreased less markedly than in non-smokers, while HDL-C decreased more rapidly while the LDL-C/HDL-C ratio increased. In subjects treated with lipid-lowering drugs, TC, LDL-C and non-HDL-C decreased more markedly and HDL-C less markedly than in untreated subjects while TG and LDL-C/HDL-C remained stable or increased in treatment naïve subjects. We conclude, that in this ageing population we observed marked changes in blood lipids over a 12 year follow up, with decreasing trajectories of TC, LDL-C and non-HDL-C and mixed trajectories of TG. The findings suggest that monitoring of age-related trajectories in blood lipids may improve prediction of CVD risk beyond single measurements.

scholarly journals Chromosome Xq23 is associated with lower atherogenic lipid concentrations and favorable cardiometabolic indices

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pradeep Natarajan ◽  
◽  
Akhil Pampana ◽  
Sarah E. Graham ◽  
Sanni E. Ruotsalainen ◽  
...  
Keyword(s):  
X Chromosome ◽  
Blood Lipids ◽  
Ldl Cholesterol ◽  
Blood Lipid ◽  
Lipid Lowering ◽  
High Coverage ◽  
Abdominal Mri ◽  
Males And Females ◽  
Atherogenic Lipid

AbstractAutosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min P = 8.5 × 10−72), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (P = 1.7 × 10−4), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (P = 1.4 × 10−5). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased CHRDL1 gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids.

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