scholarly journals Using genetics to understand the causal influence of higher BMI on depression

2018 ◽  
Vol 48 (3) ◽  
pp. 834-848 ◽  
Author(s):  
Jessica Tyrrell ◽  
Anwar Mulugeta ◽  
Andrew R Wood ◽  
Ang Zhou ◽  
Robin N Beaumont ◽  
...  
Keyword(s):  
Risk Score ◽  
Genetic Risk ◽  
Mendelian Randomization ◽  
Genetic Risk Score ◽  
Self Report ◽  
Uk Biobank ◽  
Men And Women ◽  
Statistical Confidence ◽  
The Uk ◽  
Genetically Determined

Abstract Background Depression is more common in obese than non-obese individuals, especially in women, but the causal relationship between obesity and depression is complex and uncertain. Previous studies have used genetic variants associated with BMI to provide evidence that higher body mass index (BMI) causes depression, but have not tested whether this relationship is driven by the metabolic consequences of BMI nor for differences between men and women. Methods We performed a Mendelian randomization study using 48 791 individuals with depression and 291 995 controls in the UK Biobank, to test for causal effects of higher BMI on depression (defined using self-report and Hospital Episode data). We used two genetic instruments, both representing higher BMI, but one with and one without its adverse metabolic consequences, in an attempt to ‘uncouple’ the psychological component of obesity from the metabolic consequences. We further tested causal relationships in men and women separately, and using subsets of BMI variants from known physiological pathways. Results Higher BMI was strongly associated with higher odds of depression, especially in women. Mendelian randomization provided evidence that higher BMI partly causes depression. Using a 73-variant BMI genetic risk score, a genetically determined one standard deviation (1 SD) higher BMI (4.9 kg/m2) was associated with higher odds of depression in all individuals [odds ratio (OR): 1.18, 95% confidence interval (CI): 1.09, 1.28, P = 0.00007) and women only (OR: 1.24, 95% CI: 1.11, 1.39, P = 0.0001). Meta-analysis with 45 591 depression cases and 97 647 controls from the Psychiatric Genomics Consortium (PGC) strengthened the statistical confidence of the findings in all individuals. Similar effect size estimates were obtained using different Mendelian randomization methods, although not all reached P < 0.05. Using a metabolically favourable adiposity genetic risk score, and meta-analysing data from the UK biobank and PGC, a genetically determined 1 SD higher BMI (4.9 kg/m2) was associated with higher odds of depression in all individuals (OR: 1.26, 95% CI: 1.06, 1.50], P = 0.010), but with weaker statistical confidence. Conclusions Higher BMI, with and without its adverse metabolic consequences, is likely to have a causal role in determining the likelihood of an individual developing depression.

scholarly journals Mendelian randomization provides evidence for a causal effect of higher serum IGF-1 concentration on risk of hip and knee osteoarthritis

Rheumatology ◽  
2020 ◽  
Author(s):  
April Hartley ◽  
Eleanor Sanderson ◽  
Lavinia Paternoster ◽  
Alexander Teumer ◽  
Robert C Kaplan ◽  
...  
Keyword(s):  
Risk Score ◽  
Genetic Risk ◽  
Odds Ratio ◽  
Genome Wide Association Study ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Genetic Risk Score ◽  
Uk Biobank ◽  
Knee Oa ◽  
Increased Risk

Abstract Objectives How insulin-like growth factor-1 (IGF-1) is related to OA is not well understood. We determined relationships between IGF-1 and hospital-diagnosed hand, hip and knee OA in UK Biobank, using Mendelian randomization (MR) to determine causality. Methods Serum IGF-1 was assessed by chemiluminescent immunoassay. OA was determined using Hospital Episode Statistics. One-sample MR (1SMR) was performed using two-stage least-squares regression, with an unweighted IGF-1 genetic risk score as an instrument. Multivariable MR included BMI as an additional exposure (instrumented by BMI genetic risk score). MR analyses were adjusted for sex, genotyping chip and principal components. We then performed two-sample MR (2SMR) using summary statistics from Cohorts for Heart and Aging Research in Genetic Epidemiology (CHARGE) (IGF-1, N = 30 884) and the recent genome-wide association study meta-analysis (N = 455 221) of UK Biobank and Arthritis Research UK OA Genetics (arcOGEN). Results A total of 332 092 adults in UK Biobank had complete data. Their mean (s.d.) age was 56.5 (8.0) years and 54% were female. IGF-1 was observationally related to a reduced odds of hand OA [odds ratio per doubling = 0.87 (95% CI 0.82, 0.93)], and an increased odds of hip OA [1.04 (1.01, 1.07)], but was unrelated to knee OA [0.99 (0.96, 1.01)]. Using 1SMR, we found strong evidence for an increased risk of hip [odds ratio per s.d. increase = 1.57 (1.21, 2.01)] and knee [1.30 (1.07, 1.58)] OA with increasing IGF-1 concentration. By contrast, we found no evidence for a causal effect of IGF-1 concentration on hand OA [0.98 (0.57, 1.70)]. Results were consistent when estimated using 2SMR and in multivariable MR analyses accounting for BMI. Conclusion We have found evidence that increased serum IGF-1 is causally related to higher risk of hip and knee OA.

scholarly journals Blood Eosinophil Count and Metabolic, Cardiac and Pulmonary Outcomes: A Mendelian Randomization Study

2018 ◽  
Vol 21 (2) ◽  
pp. 89-100 ◽  
Author(s):  
Marzyeh Amini ◽  
Judith M. Vonk ◽  
Ali Abbasi ◽  
Bram P. Prins ◽  
Marcel Bruinenberg ◽  
...  
Keyword(s):  
Risk Score ◽  
Genetic Risk ◽  
Eosinophil Count ◽  
Genome Wide Association Study ◽  
Mendelian Randomization ◽  
Genetic Risk Score ◽  
Blood Eosinophil ◽  
Summary Statistics ◽  
Blood Eosinophil Count ◽  
Genetically Determined

Blood eosinophil count is associated with a variety of common complex outcomes in epidemiological observation. The aim of this study was to explore the causal association between determined blood eosinophil count and 20 common complex outcomes (10 metabolic, 6 cardiac, and 4 pulmonary). Through Mendelian randomization, we investigated genetic evidence for the genetically determined eosinophil in association with each outcomes using individual-level LifeLines cohort data (n = 13,301), where a weighted eosinophil genetic risk score comprising five eosinophil associated variants was created. We further examined the associations of the genetically determined eosinophil with those outcomes using summary statistics obtained from genome-wide association study consortia (6 consortia and 14 outcomes). Blood eosinophil count, by a 1-SD genetically increased, was not statistically associated with common complex outcomes in the LifeLines. Using the summary statistics, we showed that a higher genetically determined eosinophil count had a significant association with lower odds of obesity (odds ratio (OR) 0.81, 95% confidence interval (CI) [0.74, 0.89]) but not with the other traits and diseases. To conclude, an elevated eosinophil count is unlikely to be causally associated to higher risk of metabolic, cardiac, and pulmonary outcomes. Further studies with a stronger genetic risk score for eosinophil count may support these results.

scholarly journals A Mendelian randomisation study of smoking causality in IPF compared with COPD

2020 ◽  
Author(s):  
Anna Duckworth ◽  
Michael A. Gibbons ◽  
Robin N Beaumont ◽  
Andrew R Wood ◽  
Howard Almond ◽  
...  
Keyword(s):  
Risk Score ◽  
Genetic Risk ◽  
Genetic Risk Score ◽  
Disease Status ◽  
Disease Prevalence ◽  
Mendelian Randomisation ◽  
Uk Biobank ◽  
Genetic Technique ◽  
Never Smokers ◽  
The Uk

AbstractIn a normal year, the fatal lung disease Idiopathic Pulmonary Fibrosis (IPF) accounts for ∼1% of UK deaths. Smoking is a recognised risk factor for IPF but the question of causality remains unanswered. Here, we used data from the UK Biobank (UKBB) and the well-established genetic technique of Mendelian randomisation (MR) methods to investigate whether smoking is causal for IPF compared with COPD, where causality is established.We looked at observational associations in unrelated Europeans, with 871 IPF cases, 11,413 COPD cases and 366,942 controls. We performed analyses using one-sample MR to test for inferred smoking causality in ever smokers using genetic variants that have a previously demonstrated association with smoking heaviness.Strong associations between disease status and ever having smoked were found in both IPF (OR = 1.52; 95%CI:1.32-1.74; P=2.4×10−8) and COPD (OR= 5.77; 95%CI:5.48-6.07; P<1×10−15). Using MR, a one allele increase in smoking volume genetic risk score was associated with higher odds of COPD in ever smokers, (OR = 4.32; 95%CI:3.37-5.54; P<1×10−15), but no association was seen in IPF (OR=0.55; 95%CI: 0.17-1.81; P=0.33). No association was found between the genetic risk score and disease prevalence in never smokers with IPF (OR = 1.00; 95%CI:0.98-1.02; P=1.00) or COPD (OR = 1.00; 95%CI:0.99-1.01; P=0.53).Although both IPF and COPD are observationally associated with smoking, our analysis provides evidence inferring that the association is causal in COPD but there is no such evidence in IPF. This suggests that other environmental exposures also need consideration in IPF.

Mendelian Randomization Focused Analysis of Vitamin D on the Secondary Prevention of Ischemic Stroke

Stroke ◽  
2021 ◽  
Author(s):  
Yap-Hang Chan ◽  
C. Mary Schooling ◽  
Jie Zhao ◽  
Shiu-Lun Au Yeung ◽  
Jo Jo Hai ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Vitamin D ◽  
Ischemic Stroke ◽  
Risk Score ◽  
Genetic Risk ◽  
Odds Ratio ◽  
Mendelian Randomization ◽  
De Novo ◽  
Genetic Risk Score ◽  
Ischemic Disease

Background and Purpose: Experimental studies showed vitamin D (Vit-D) could promote vascular regeneration and repair. Prior randomized studies had focused mainly on primary prevention. Whether Vit-D protects against ischemic stroke and myocardial infarction recurrence among subjects with prior ischemic insults was unknown. Here, we dissected through Mendelian randomization any effect of Vit-D on the secondary prevention of recurrent ischemic stroke and myocardial infarction. Methods: Based on a genetic risk score for Vit-D constructed from a derivation cohort sample (n=5331, 45% Vit-D deficient, 89% genotyped) via high-throughput exome-chip screening of 12 prior genome-wide association study–identified genetic variants of Vit-D mechanistic pathways ( rs2060793 , rs4588 , and rs7041 ; F statistic, 73; P <0.001), we performed a focused analysis on prospective recurrence of myocardial infarction (MI) and ischemic stroke in an independent subsample with established ischemic disease (n=441, all with prior first ischemic event; follow-up duration, 41.6±14.3 years) under a 2-sample, individual-data, prospective Mendelian randomization approach. Results: In the ischemic disease subsample, 11.1% (n=49/441) had developed recurrent ischemic stroke or MI and 13.3% (n=58/441) had developed recurrent or de novo ischemic stroke/MI. Kaplan-Meier analyses showed that genetic risk score predicted improved event-free survival from recurrent ischemic stroke or MI (log-rank, 13.0; P =0.001). Cox regression revealed that genetic risk score independently predicted reduced risk of recurrent ischemic stroke or MI combined (hazards ratio, 0.62 [95% CI, 0.48–0.81]; P <0.001), after adjusted for potential confounders. Mendelian randomization supported that Vit-D is causally protective against the primary end points of recurrent ischemic stroke or MI (Wald estimate: odds ratio, 0.55 [95% CI, 0.35–0.81]) and any recurrent or de novo ischemic stroke/MI (odds ratio, 0.64 [95% CI, 0.42–0.91]) and recurrent MI alone (odds ratio, 0.52 [95% CI, 0.30–0.81]). Conclusions: Genetically predicted lowering in Vit-D level is causal for the recurrence of ischemic vascular events in persons with prior ischemic stroke or MI.

scholarly journals Genetic Risk Score for Predicting Schizophrenia Using Human Chromosomal-Scale Length Variation

2021 ◽  
Author(s):  
Christopher Toh ◽  
James P. Brody
Keyword(s):  
Risk Score ◽  
Genetic Risk ◽  
Germ Line ◽  
Genetic Risk Score ◽  
Single Gene ◽  
Characteristic Curve ◽  
Machine Learning Algorithms ◽  
Length Variation ◽  
Uk Biobank ◽  
Scale Length

Abstract Studies indicate that schizophrenia has a genetic component, however it cannot be isolated to a single gene. We aimed to determine how well one could predict that a person will develop schizophrenia based on their germ line genetics. We compared 1129 people from the UK Biobank dataset who had a diagnosis of schizophrenia to an equal number of age matched people drawn from the general UK Biobank population. For each person, we constructed a profile consisting of numbers. Each number characterized the length of segments of chromosomes. We tested several machine learning algorithms to determine which was most effective in predicting schizophrenia and if any improvement in prediction occurs by breaking the chromosomes into smaller chunks. We found that the stacked ensemble, performed best with an area under the receiver operating characteristic curve (AUC) of 0.545 (95% CI 0.539-0.550). We noted an increase in the AUC by breaking the chromosomes into smaller chunks for analysis. Using SHAP values, we identified the X chromosome as the most important contributor to the predictive model. We conclude that germ line chromosomal scale length variation data could provide an effective genetic risk score for schizophrenia which performs better than chance.

Abstract P254: Genetic Risk Score for Height and the Incidence of Venous Thromboembolism: A Prospective Study

Circulation ◽  
2016 ◽  
Vol 133 (suppl_1) ◽  
Author(s):  
Nicholas S Roetker ◽  
James S Pankow ◽  
Pamela L Lutsey ◽  
Weihong Tang ◽  
Michael A Rosenberg ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Causal Relationship ◽  
Risk Score ◽  
Genetic Risk ◽  
Mendelian Randomization ◽  
Genetic Risk Score ◽  
Statistical Significance ◽  
Body Height ◽  
Health Study ◽  
Cardiovascular Health Study

Introduction: Several observational studies have shown that taller body height is associated with greater risk of venous thromboembolism (VTE), but it is not known whether the association is causal. We used instrumental variable analysis (Mendelian randomization) to explore the causal relationship between height and VTE using a genetic risk score (GRS) for height as the instrument. Hypothesis: There is a causal relationship between taller standing height and greater risk of VTE, as demonstrated by a Mendelian randomization approach. Methods: We created a weighted GRS for height in white men and women in the Longitudinal Investigation of Thromboembolism Etiology [consisting of two longitudinal cohort studies: Atherosclerosis Risk in Communities (ARIC) and Cardiovascular Health Study (CHS)] using 668 single nucleotide polymorphisms from a recently published meta-analysis. Incident hospitalized VTE events were identified and verified by physician review of medical records. We estimated the association and causal risk differences (RD) and 95% confidence intervals (CI) for VTE incidence per standard deviation (SD) increment in height (9.4 cm). The association models were adjusted for age, sex, waist circumference, and study site. Results: There were 9,137 ARIC and 3,163 CHS participants at risk for VTE at baseline and with genetic data, and they experienced 367 (ARIC) and 105 (CHS) incident VTE events over a median 22.7 and 11.8 years of follow-up, respectively. Baseline age ranges were 45-64 and 65-98 years and mean heights were 169 and 165 cm in ARIC and CHS, respectively. The GRS was a strong instrument for height (R 2 =0.08 in ARIC and R 2 =0.07 in CHS) and had little to no correlation with other measured VTE risk factors (all R 2 ≤0.01). In ARIC, taller height was associated with greater risk of VTE [association VTE RD: 1.0% per SD in height (95% CI: 0.3 to 1.6%)]. The causal RD had the same magnitude as the association RD, but did not quite reach statistical significance [causal VTE RD per SD in height: 1.1% (95% CI: -0.3 to 2.5%)]. Predicted risks of VTE at the 10th and 90th percentiles of height (157 and 181 cm) were 2.6% and 5.4%, respectively, representing more than a doubling of risk. There was no association between height and VTE risk in CHS [association VTE RD per SD in height: 0.1% (95% CI: -1.0 to 1.2%); causal VTE RD per SD in height: -0.3% (95% CI: -2.5 to 1.9%)]. Conclusion: Taller height was associated with greater VTE risk with some supporting causal evidence in middle-aged adults from ARIC, but there was no relation between height and VTE in older adults from CHS. Future studies should further explore the causal relation between height and VTE among different age groups.

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