scholarly journals Serum iron status and the risk of breast cancer in the European population: a two-sample Mendelian randomisation study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chenyang Hou ◽  
Qingzhi Hou ◽  
Xing Xie ◽  
Huifeng Wang ◽  
Yueliang Chen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Instrumental Variables ◽  
Serum Iron ◽  
Iron Status ◽  
Mendelian Randomisation ◽  
Nucleotide Polymorphisms ◽  
European Descent ◽  
Simple Mode ◽  
Liberal Approach ◽  
Mr Study

Abstract Background Previous observational studies have provided conflicting results on the association between serum iron status and the risk of breast cancer. Considering the relevance of this relationship to breast cancer prevention, its elucidation is warranted. Object We used a two-sample Mendelian randomisation (MR) study to explore the causal relationship between serum iron status and the risk of breast cancer. Method To select single nucleotide polymorphisms (SNPs) that could be used as instrumental variables for iron status, we used the Genetics of Iron Status consortium, which includes 11 discovery and 8 replication cohorts, encompassing 48,972 individuals of European descent. Moreover, we used the OncoArray network to select SNPs that could be considered instrumental variables for the outcome of interest (breast cancer); this dataset included 122,977 individuals of European descent with breast cancer and 105,974 peers without breast cancer. Both conservative (SNPs associated with overall iron status markers) and liberal (SNPs associated with the levels of at least one iron status marker) approaches were used as part of the MR analysis. For the former, we used an inverse-variance weighted (IVW) method, whereas for the latter, we used the IVW, MR-Egger regression, weighted median and simple mode methods. Results When the conservative approach was used, iron status showed no significant association with the risk of breast cancer or any of its subtypes. However, when the liberal approach was used, transferrin levels were found to be positively associated with the risk of ER-negative breast cancer based on the simple mode method (OR for MR, 1.225; 95% CI, 1.064, 1.410; P = 0.030). Nevertheless, the levels of the other iron status markers showed no association with the risk of breast cancer or its subtypes (P > 0.05). Conclusion In our MR study, the liberal approach suggested that changes in the concentration of transferrin could increase the risk of ER-negative breast cancer, although the levels of other iron status markers had no effect on the risk of breast cancer or its subtypes. This should be verified in future studies.

scholarly journals Serum Iron Status and the Risk of Breast Cancer in Europeans: A 2-Sample Mendelian Randomisation Study

2020 ◽  
Author(s):  
Chenyang Hou ◽  
Qingzhi Hou ◽  
Xing Xie ◽  
Huifeng Wang ◽  
Yueliang Chen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Instrumental Variables ◽  
Serum Iron ◽  
Iron Status ◽  
Mendelian Randomisation ◽  
Nucleotide Polymorphisms ◽  
Simple Mode ◽  
Inverse Variance ◽  
Liberal Approach ◽  
Mr Study

Abstract Background: Previous observational studies showed that there was a conflict about serum iron status and the risk of breast cancer, which could have an impact on the prevention of breast cancer.Object: We used a two sample Mendelian randomisation (MR) study to explore the causal relationship between iron status and the risk of breast cancer.Method: To select single nucleotide polymorphisms (SNPs) which could be used as instrumental variables for iron status, we used the Genetics of Iron Status consortium. Moreover, we used the OncoArray network to select SNPs of instrumental variables for the outcome (breast cancer). The conservative instruments (SNPs were all consistent with iron status) and liberal instruments (SNPs was associated with at least one of iron status) were used in MR analysis. In the conservative instruments set we used an inverse-variance weighted (IVW) approach, and in the liberal instruments set we used the IVW, MR-Egger regression, weighted median and simple mode approach. Results: In the conservative approach, none of the iron status were statistically significant for breast cancer or its subtypes. And in the liberal approach, transferrin was positively associated with ER-negative breast cancer by simple mode (OR for MR: 1.225; 95% CI: 1.064, 1.410; P=0.030). However, other iron statuses had no association with breast cancer or its subtypes (P>0.05).Conclusion: Our MR study, in the liberal approach, suggested that changes in the concentration of transferrin could increase the risk of ER-negative breast cancer, and other iron statuses had no effect on breast cancer or its subtypes. This could be verified in future studies.

scholarly journals Maternal iron status during pregnancy and respiratory and atopic outcomes in the offspring: a Mendelian randomisation study

2018 ◽  
Vol 5 (1) ◽  
pp. e000275 ◽  
Author(s):  
Annabelle Bédard ◽  
Sarah J Lewis ◽  
Stephen Burgess ◽  
A John Henderson ◽  
Seif O Shaheen
Keyword(s):  
Birth Cohort ◽  
Iron Status ◽  
Transferrin Saturation ◽  
Late Pregnancy ◽  
Forced Expiratory Volume ◽  
Risk Scores ◽  
Mendelian Randomisation ◽  
Nucleotide Polymorphisms ◽  
Common Genetic Variants ◽  
Maternal Iron

IntroductionLimited evidence from birth cohort studies suggests that lower prenatal iron status may be a risk factor for childhood respiratory and atopic outcomes, but these observational findings may be confounded. Mendelian randomisation (MR) can potentially provide unconfounded estimates of causal effects by using common genetic variants as instrumental variables. We aimed to study the relationship between prenatal iron status and respiratory and atopic outcomes in the offspring using MR.MethodsIn the Avon Longitudinal Study of Parents and Children birth cohort, we constructed four maternal genotypic risk scores by summing the total number of risk alleles (associated with lower iron status) across single nucleotide polymorphisms known to be associated with at least one of four iron biomarkers (serum iron, ferritin, transferrin and transferrin saturation). We used MR to study their associations with respiratory and atopic outcomes in children aged 7–9 years (n=6002).ResultsWhen analyses were restricted to mothers without iron supplementation during late pregnancy, negative associations were found between the maternal transferrin saturation score and childhood forced expiratory volume in 1 s and forced vital capacity (difference in age, height and gender-adjusted SD units per SD increase in genotypic score: −0.05 (−0.09, −0.01) p=0.03, and −0.04 (−0.08, 0.00) p=0.04, respectively).ConclusionUsing MR we have found weak evidence suggesting that low maternal iron status during pregnancy may cause impaired childhood lung function.

scholarly journals Genetically predicted physical activity levels are associated with lower colorectal cancer risk: a Mendelian randomisation study

2021 ◽  
Author(s):  
Xiaomeng Zhang ◽  
Evropi Theodoratou ◽  
Xue Li ◽  
Susan M. Farrington ◽  
Philip J. Law ◽  
...  
Keyword(s):  
Physical Activity ◽  
Colorectal Cancer ◽  
Cancer Risk ◽  
Body Fat ◽  
Instrumental Variables ◽  
Sedentary Time ◽  
Colorectal Cancer Risk ◽  
European Ancestry ◽  
Mendelian Randomisation ◽  
Mr Study

Abstract Background We conducted a Mendelian randomisation (MR) study to investigate whether physical activity (PA) causes a reduction of colorectal cancer risk and to understand the contributions of effects mediated through changes in body fat. Methods Common genetic variants associated with self-reported moderate-to-vigorous PA (MVPA), acceleration vector magnitude PA (AMPA) and sedentary time were used as instrumental variables. To control for confounding effects of obesity, we included instrumental variables for body mass index (BMI), body fat percentage, waist circumference and arm, trunk and leg fat ratios. We analysed the effect of these instrumental variables in a colorectal cancer genome-wide association study comprising 31,197 cases and 61,770 controls of European ancestry by applying two-sample and multivariable MR study designs. Results We found decreased colorectal cancer risk for genetically represented measures of MVPA and AMPA that were additional to effects mediated through genetic measures of obesity. Odds ratio and 95% confidence interval (CI) per standard deviation increase in MVPA and AMPA was 0.56 (0.31, 1.01) and 0.60 (0.41, 0.88), respectively. No association has been found between sedentary time and colorectal cancer risk. The proportion of effect mediated through BMI was 2% (95% CI: 0, 14) and 32% (95% CI: 12, 46) for MVPA and AMPA, respectively. Conclusion These findings provide strong evidence to reinforce public health measures on preventing colorectal cancer that promote PA at a population level regardless of body fatness.

scholarly journals Mendelian randomisation study of smoking exposure in relation to breast cancer risk

2021 ◽  
Author(s):  
Hanla A. Park ◽  
Sonja Neumeyer ◽  
Kyriaki Michailidou ◽  
Manjeet K. Bolla ◽  
Qin Wang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Risk ◽  
Cancer Risk ◽  
Causal Effect ◽  
Association Studies ◽  
Sensitivity Analyses ◽  
Mendelian Randomisation ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Smoking Exposure

Abstract Background Despite a modest association between tobacco smoking and breast cancer risk reported by recent epidemiological studies, it is still equivocal whether smoking is causally related to breast cancer risk. Methods We applied Mendelian randomisation (MR) to evaluate a potential causal effect of cigarette smoking on breast cancer risk. Both individual-level data as well as summary statistics for 164 single-nucleotide polymorphisms (SNPs) reported in genome-wide association studies of lifetime smoking index (LSI) or cigarette per day (CPD) were used to obtain MR effect estimates. Data from 108,420 invasive breast cancer cases and 87,681 controls were used for the LSI analysis and for the CPD analysis conducted among ever-smokers from 26,147 cancer cases and 26,072 controls. Sensitivity analyses were conducted to address pleiotropy. Results Genetically predicted LSI was associated with increased breast cancer risk (OR 1.18 per SD, 95% CI: 1.07–1.30, P = 0.11 × 10–2), but there was no evidence of association for genetically predicted CPD (OR 1.02, 95% CI: 0.78–1.19, P = 0.85). The sensitivity analyses yielded similar results and showed no strong evidence of pleiotropic effect. Conclusion Our MR study provides supportive evidence for a potential causal association with breast cancer risk for lifetime smoking exposure but not cigarettes per day among smokers.

scholarly journals Urticaria and increased risk of rheumatoid arthritis: a two-sample Mendelian randomisation study in European population

2021 ◽  
Author(s):  
Xue Yu ◽  
Ming-Gang Deng ◽  
Zi-Ying Tang ◽  
Zhi-Jiang Zhang
Keyword(s):  
Rheumatoid Arthritis ◽  
Instrumental Variables ◽  
Meta Analysis ◽  
Sufficient Evidence ◽  
Mendelian Randomisation ◽  
Nucleotide Polymorphisms ◽  
Global Test ◽  
Increased Risk ◽  
Variant Analysis ◽  
Summary Data

ABSTRACT Background In recent years, a growing body of observational studies suggest that urticaria is associated with a higher risk of rheumatoid arthritis (RA). However, the causal association between urticaria and RA remains unknown. Objective To investigate the causal relationship of urticaria and RA in European populations by Mendelian randomisation (MR) approach. Methods We conducted two-sample MR analyses. Eleven single-nucleotide polymorphisms associated with urticaria were used as instrumental variables. The summary data on urticaria were derived from FinnGen Data Freeze 2. The summary data on RA were obtained from a published meta-analysis using European samples. Four MR methods were applied to the MR estimates. Three heterogeneity tests, including Cochran’s Q test, single variant analysis, and leave-one-out variant analysis, were used. The pleiotropy and horizontal pleiotropy among instrumental variables were assessed with MR-Egger regression intercept, MR pleiotropy residual sum and outlier global test, and PhenoScanner. Results The MR analysis suggested that urticaria was causally associated with RA (odds ratio = 1.114, 95% confidence interval = 1.024–1.211, p = .011). No genetic pleiotropy or horizontal pleiotropy was revealed by MR-Egger regression intercept and MR pleiotropy residual sum and outlier global test. The sensitivity analysis results were relatively robust. Conclusions The MR analysis suggested there was sufficient evidence to indicate urticaria is the cause of RA.

scholarly journals The association between low-density lipoprotein cholesterol predicted by HMGCR genetic variants and breast cancer risk may be mediated by body mass index

2018 ◽  
Author(s):  
Siddhartha P. Kar ◽  
Hermann Brenner ◽  
Graham G. Giles ◽  
Dezheng Huo ◽  
Roger L. Milne ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Lipoprotein Cholesterol ◽  
Low Density ◽  
Nucleotide Polymorphisms ◽  
Low Density Lipoprotein Cholesterol ◽  
Genome Wide ◽  
A Genome ◽  
Mr Study

Orho-Melander et al. recently reported that lower low-density lipoprotein cholesterol (LDLC) as predicted by the T-allele of the variant rs12916 in HMGCR is associated with a decreased risk of developing breast cancer [odds ratio (OR) = 0.89; 95% confidence interval (CI): 0.82–0.96].1 This analysis was embedded in a wider Mendelian randomization (MR) study performed using genotype data from a prospective cohort of 26,589 individuals that included 16,022 women and 1176 incident breast cancer cases. HMGCR encodes 3-hydroxy-3-methylglutaryl-coenzyme A reductase, the enzyme inhibited by statins. The T-allele of rs12916 is associated with reduced HMGCR expression and therefore, in principle, its effects should be analogous to the effects of lifelong statin administration starting at birth.2 The MR study of Orho-Melander et al. also found that a genome-wide LDLC score based on 32 independent LDLC-associated single nucleotide polymorphisms (SNPs) was not associated with breast cancer. In light of this finding, they suggest that the protective effect of the rs12916 T-allele on breast cancer may either be specific to LDLC lowering via genetic inhibition of HMGCR or be the result of a distinct mechanism that is regulated by rs12916 and HMGCR.

scholarly journals Pro-inflammatory cytokine polymorphisms and interactions with dietary alcohol and estrogen, risk factors for invasive breast cancer using a post genome-wide analysis for gene–gene and gene–lifestyle interaction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Su Yon Jung ◽  
Jeanette C. Papp ◽  
Eric M. Sobel ◽  
Matteo Pellegrini ◽  
Herbert Yu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Breast Cancer Risk ◽  
Cancer Risk ◽  
Visceral Obesity ◽  
Cumulative Exposure ◽  
Environment Interaction ◽  
Dependent Manner ◽  
Nucleotide Polymorphisms ◽  
Genome Wide ◽  
Reduction Methods

AbstractMolecular and genetic immune-related pathways connected to breast cancer and lifestyles in postmenopausal women are not fully characterized. In this study, we explored the role of pro-inflammatory cytokines such as C-reactive protein (CRP) and interleukin-6 (IL-6) in those pathways at the genome-wide level. With single-nucleotide polymorphisms (SNPs) in the biomarkers and lifestyles together, we further constructed risk profiles to improve predictability for breast cancer. Our earlier genome-wide association gene-environment interaction study used large cohort data from the Women’s Health Initiative Database for Genotypes and Phenotypes Study and identified 88 SNPs associated with CRP and IL-6. For this study, we added an additional 68 SNPs from previous GWA studies, and together with 48 selected lifestyles, evaluated for the association with breast cancer risk via a 2-stage multimodal random survival forest and generalized multifactor dimensionality reduction methods. Overall and in obesity strata (by body mass index, waist, waist-to-hip ratio, exercise, and dietary fat intake), we identified the most predictive genetic and lifestyle variables. Two SNPs (SALL1 rs10521222 and HLA-DQA1 rs9271608) and lifestyles, including alcohol intake, lifetime cumulative exposure to estrogen, and overall and visceral obesity, are the most common and strongest predictive markers for breast cancer across the analyses. The risk profile that combined those variables presented their synergistic effect on the increased breast cancer risk in a gene–lifestyle dose-dependent manner. Our study may contribute to improved predictability for breast cancer and suggest potential interventions for the women with the risk genotypes and lifestyles to reduce their breast cancer risk.

scholarly journals The Investigation of Associations between TP53 rs1042522, BBC3 rs2032809, CCND1 rs9344, EGFR rs2227983 Polymorphisms and Breast Cancer Phenotype and Prognosis

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1419
Author(s):  
Justina Bekampytė ◽  
Agnė Bartnykaitė ◽  
Aistė Savukaitytė ◽  
Rasa Ugenskienė ◽  
Erika Korobeinikova ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Regression Analysis ◽  
Cox Regression ◽  
Cancer Prognosis ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Cox Regression Analysis ◽  
Pcr Rflp ◽  
Oncological Diseases ◽  
Cancer Phenotype

Breast cancer is one of the most common oncological diseases among women worldwide. Cell cycle and apoptosis—related genes TP53, BBC3, CCND1 and EGFR play an important role in the pathogenesis of breast cancer. However, the roles of single nucleotide polymorphisms (SNPs) in these genes have not been fully defined. Therefore, this study aimed to analyze the association between TP53 rs1042522, BBC3 rs2032809, CCND1 rs9344 and EGFR rs2227983 polymorphisms and breast cancer phenotype and prognosis. For the purpose of the analysis, 171 Lithuanian women were enrolled. Genomic DNA was extracted from peripheral blood; PCR-RFLP was used for SNPs analysis. The results showed that BBC3 rs2032809 was associated with age at the time of diagnosis, disease progression, metastasis and death. CCND1 rs9344 was associated with tumor size, however an association resulted in loss of significance after Bonferroni correction. In survival analysis, significant associations were observed between BBC3 rs2032809 and OS, PFS and MFS. EGFR rs2227983 also showed some associations with OS and PFS (univariate Cox regression analysis). However, the results were in loss of significance (multivariate Cox regression analysis). In conclusion, BBC3 rs2032809 polymorphism was associated with breast cancer phenotype and prognosis. Therefore, it could be applied as potential markers for breast cancer prognosis.

scholarly journals Causal Association between Periodontitis and Parkinson’s Disease: A Bidirectional Mendelian Randomization Study

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
João Botelho ◽  
Vanessa Machado ◽  
José João Mendes ◽  
Paulo Mascarenhas
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Instrumental Variables ◽  
Mendelian Randomization ◽  
Association Studies ◽  
European Ancestry ◽  
Genome Wide Association Studies ◽  
Nucleotide Polymorphisms ◽  
Genetic Liability ◽  
Bidirectional Association

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.

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