The role of age at menarche and age at menopause in Alzheimer's disease: evidence from a bidirectional mendelian randomization study.
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ABSTRACT:
SUBMITTER: Li M
PROVIDER: S-EPMC8386554 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundHormonal reproductive factors have been suggested to play an important role in the etiology of rheumatoid arthritis (RA), an autoimmune inflammatory disorder affecting primarily women. We conducted a two-sample Mendelian randomization (MR) study examining three relevant exposures, age at menarche (AAM), age at natural menopause (ANM), and age at first birth (AFB) with the risk of RA.MethodsWe collected summary statistics from the hitherto largest GWAS conducted in AAM (N = 329,345), ANM (N = 69,360), AFB (N = 251,151), and RA (Ncase = 14,361, Ncontrol = 43,923), all of European ancestry. We constructed strong instruments using hundreds of exposure-associated genetic variants and estimated causal relationship through different MR approaches including an inverse-variance weighted method, an MR-Egger regression and a weighted median method. We conducted a multivariable MR to control for pleiotropic effect acting in particular through obesity and socioeconomic status. We also performed important sensitivity analyses to verify model assumptions.ResultsWe did not find any evidence in support for a causal association between genetically predicted reproductive factors and risk of RA (ORper-SD increment in AAM = 1.06 [0.98-1.15]; ORper-SD increment in ANM = 1.05 [0.98-1.11], OR per-SD increment in AFB = 0.85 [0.65-1.10]). Results remained consistent after removing palindromic SNPs (ORper-SD increment in AAM = 1.06 [0.97-1.15], ORper-SD increment in ANM = 1.05 [0.98-1.13], ORper-SD increment in AFB = 0.81 [0.61-1.07]) or excluding SNPs associated with potential confounding traits (ORper-SD increment in AAM = 1.03 [0.94-1.12], ORper-SD increment in ANM = 1.04 [0.95-1.14]). No outlying instrument was identified through the leave-one-out analysis.ConclusionsOur MR study does not convincingly support a casual effect of reproductive factors, as reflected by age at menarche, age at menopause, and age at first birth, on the development of RA. Despite the largely augmented set of instruments we used, these instruments only explained a modest proportion of phenotypic variance of exposures. Our knowledge regarding this topic is still insufficient and future studies with larger sample size should be designed to replicate or dispute our findings.
| S-EPMC8034136 | biostudies-literature
Project description:BackgroundThe roles of age at menarche and age at menopause in the etiology of lung and colorectal cancers are unclear.ObjectiveWe aimed to investigate potential causal associations between age at menarche, age at natural menopause, and risk of lung and colorectal cancers using a Mendelian randomization (MR) approach.MethodsFrom the Trøndelag Health Study in Norway, we defined two cohorts of 35 477 and 17 118 women to study the effects of age at menarche and age at natural menopause, respectively. We ran univariable MR to evaluate the potential causal associations. We performed multivariable MR adjusting for genetic variants of adult body mass index (BMI) to estimate the direct effect of age at menarche.ResultsGenetically predicted 1-year increase in age at menarche was associated with a lower risk of lung cancer overall (hazard ratio [HR, 0.64; 95% CI, 0.48-0.86), lung adenocarcinoma (HR, 0.61; 95% CI, 0.38-0.99), and lung non-adenocarcinoma (HR, 0.66; 95% CI, 0.45-0.95). After adjusting for adult BMI using a multivariable MR model, the direct effect estimates reduced to HR 0.72 (95% CI, 0.54-0.95) for lung cancer overall, HR 0.67 (95% CI, 0.43-1.03) for lung adenocarcinoma, and HR 0.77 (95% CI, 0.54-1.09) for lung non-adenocarcinoma. Age at menarche was not associated with colorectal cancer. Moreover, genetically predicted age at natural menopause was not associated with lung and colorectal cancers.ConclusionOur MR study suggested that later age at menarche was causally associated with a decreased risk of lung cancer overall and its subtypes, and adult BMI might be a mediator.
| S-EPMC10315561 | biostudies-literature
Project description:BackgroundThere is increasing evidence that sex hormones are involved in the development of lung cancer, but the correlation between the reproductive behavior that changes sex hormone levels and lung cancer is not yet clear. Many previous studies have investigated the association between reproductive factors and lung cancer risk, but the results have been inconsistent. Therefore, we conducted a two-sample Mendelian randomization (MR) analysis to explore the potential relationship between age at first sexual intercourse (AFS), age at menarche, and age at menopause, and lung cancer.MethodsWe performed a MR analysis of the data from the genome-wide association study (GWAS) of European ancestry to evaluate the independent effects of three reproductive behaviors on lung cancer overall (LUCA), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and small cell lung cancer (SCLC). We mainly used the inverse-variance weighting method for the MR analysis. Sensitivity was determined by a MR-pleiotropy residual sum and outlier analysis, a weighted median analysis, a MR-Egger analysis, and a leave-one-out analysis.ResultsThe MR analysis results revealed that older AFS had a causal relationship with LUCA [odds ratio (OR) =0.6283, 95% confidence interval (CI): 0.4959-0.7961, P=0.0001), LUAD (OR =0.7042, 95% CI: 0.4967-0.9984, P=0.049), and LUSC (OR =0.6231, 95% CI: 0.4386-0.8853, P=0.0083).ConclusionsOur results revealed a causal relationship between older AFS and a lower risk of lung cancer. Our findings emphasize the importance of providing sex education, as early sexual intercourse may have undesirable effects. In addition, early psychological treatment is also essential.
| S-EPMC11304150 | biostudies-literature
Project description:ObjectivesTo determine whether the age at menarche (AAM) and the age at menopause (ANM) are causally related to the development of sepsis.MethodsWe performed a two-sample Mendelian randomization (MR) analysis by utilizing summary statistics from genome-wide association study (GWAS) datasets for both the exposure and outcome variables. Single nucleotide polymorphisms (SNPs) that exhibited significant associations with AAM and ANM were chosen as instrumental variables to estimate the causal effects on sepsis. Our study employed a variety of methods, including MR-Egger regression, weighted median estimation, inverse variance weighting, a simple model, and a weighted model. Odds ratios (ORs) along with their corresponding 95% confidence intervals (CIs) were used as the primary indicators for assessing causality. Furthermore, we conducted sensitivity analyses to explore the presence of genetic heterogeneity and validate the robustness of the tools employed.ResultOur analysis revealed a significant negative causal relationship between AAM and the risk of sepsis (IVW: OR = 0.870, 95% CI = 0.793-0.955, P = 0.003). However, our Mendelian randomization (MR) analysis did not yield sufficient evidence to support a causal link between ANM and sepsis (IVW: OR = 0.987, 95% CI = 0.971-1.004, P = 0.129).ConclusionsOur findings suggest that an earlier AAM may be associated with an increased risk of sepsis. However, we did not find sufficient evidence to support a causal relationship between ANM and sepsis.
| S-EPMC10849219 | biostudies-literature
Project description:Recent experimental studies indicated that a periodontitis-causing bacterium might be a causal factor for Alzheimer's disease (AD). We applied a two-sample Mendelian randomization (MR) approach to examine the potential causal relationship between chronic periodontitis and AD bidirectionally in the population of European ancestry. We used publicly available data of genome-wide association studies (GWAS) on periodontitis and AD. Five single-nucleotide polymorphisms (SNPs) were used as instrumental variables for periodontitis. For the MR analysis of periodontitis on risk of AD, the causal odds ratio (OR) and 95% confidence interval (CI) were derived from the GWAS of periodontitis (4,924 cases vs. 7,301 controls) and from the GWAS of AD (21,982 cases vs. 41,944 controls). Seven non-overlapping SNPs from another latest GWAS of periodontitis was used to validate the above association. Twenty SNPs were used as instrumental variables for AD. For the MR analysis of liability to AD on risk of periodontitis, the causal OR was derived from the GWAS of AD including 30,344 cases and 52,427 controls and from the GWAS of periodontitis consisted of 12,289 cases and 22,326 controls. We employed multiple methods of MR. Using the five SNPs as instruments of periodontitis, there was suggestive evidence of genetically predicted periodontitis being associated with a higher risk of AD (OR 1.10, 95% CI 1.02 to 1.19, P = 0.02). However, this association was not verified using the seven independent SNPs (OR 0.97, 95% CI 0.87 to 1.08, P = 0.59). There was no association of genetically predicted AD with the risk of periodontitis (OR 1.00, 95% CI 0.96 to 1.04, P = 0.85). In summary, we did not find convincing evidence to support periodontitis being a causal factor for the development of AD. There was also limited evidence to suggest genetic liability to AD being associated with the risk of periodontitis.
| S-EPMC6980529 | biostudies-literature
Project description:IntroductionObservational studies have indicated widespread comorbidity of white matter (WM) lesions and Alzheimer's disease (AD) in the elderly, but the causality and direction of their relationship remained unclear. Our study aims to examine the bidirectional causal relationship between WM change and AD using a genetically informed method.MethodsWe performed a bidirectional two-sample mendelian randomization (MR) study to investigate the correlation of three WM phenotypes-white matter hyperintensities (WMH, N = 18,381), fractional anisotropy (FA, N = 17,673), and mean diffusivity (MD, N = 17,467)-with AD (N = 63,926) using summary statistics from genome-wide association studies (GWAS). The inverse variance weighted method (IVW) was used to evaluate the causal estimate and alternative methods to test the heterogeneity, horizontal pleiotropy, and outliers.ResultsThere was no significant causal evidence of WM MRI markers on AD across all MR methods. We identified significant evidence of causal effects of AD on the risk of WMH (OR 1.06, 95% CI 1.03-1.10, p < 0.01). The same direction of effects was observed in MR-Egger, weighted median, and weighted mode analysis. Besides, we also observed a risk causal relationship between AD with MD in MR-Egger, weighted median, and weighted mode-based methods (MR-Egger OR 1.38, 95% CI 1.07-1.79, p = 0.02; weighted median OR 1.21, 95% CI 1.02-1.45, p = 0.03; weighted mode-based OR 1.32, 95% CI 1.14-1.53, p < 0.01). However, the general significance of the causal effect of AD on WMH and MD disappeared when we removed the single nucleotide polymorphisms (SNPs) near the APOE regions, revealing that the ability of AD to increase the risk of white matter damage might be mediated by APOE to some extent. Unfortunately, we did not observe significant causal evidence of AD on FA across all MR analyses.ConclusionsIn this bidirectional MR study, we did not observe that WM injuries were associated with a higher risk of AD. Likewise, genetically predicted AD did not result in a causal effect on white matter damage. However, our research revealed that underlying mechanisms linking AD and white matter lesions might be related to the SNPs near APOE regions.
| S-EPMC9095794 | biostudies-literature
Project description:Background: Although earlier menarche age has been associated with ischemic heart disease in previous observational studies, the relationship's causation has not been shown. Through two-sample Mendelian randomization (MR), we were able to define the causal connection. Methods: We performed Mendelian Randomization (MR) analysis to explore the associations between genetically predicted AAM and IHD. Summary-level databases for exposure and outcome were selected from the MR-Base database (https://gwas.mrcieu.ac.uk/). Single-nucleotide polymorphisms (SNPs) connected to AAM at genome-wide significance level (p < 5 × 10-8) were considered as instrumental variables (IVs). We used four methods to pool MR estimates, including fixed-effects inverse variance weighting (fe-IVW), multiplicative random-effects inverse variance weighting (mre-IVW), weighted median (WM), and MR-Egger regression methods. Sensitivity analyses were performed to evaluate the robustness of the results. PhenoScanner searches and Multivariable Mendelian randomization (MVMR) analysis was used for assessing confounders. Results: 117 SNPs significantly correlated with AAM were screened as instruments, the results of three main methods showed that genetically earlier AAM may have a causal effect on the higher risk of IHD (fe-IVW: OR = 0.80, 95% CI: 0.72-0.88, p < 0.001; mre-IVW: OR = 0.80, 95% CI: 0.70-0.90, p < 0.001; WE: OR = 0.79, 95% CI: 0.66-0.93, p = 0.006). These results were consistent across sensitivity analyses. MR analysis revealed that there was still a relationship between AAM and IHD even when pleiotropic SNPs of confounders were removed employing PhenoScanner searches. In MVMR, the significant association remained after adjusting for biological sex, but it was attenuated with adjustment of body mass index including childhood and adult. Conclusion: Our MR analysis revealed a substantial genetically determined confounder-mediated relationship between an increase in genetically predicted AAM and a lower risk of IHD. By addressing the intervention of body mass index, the risk of IHD may be lowered.
| S-EPMC9671358 | biostudies-literature
Project description:PURPOSE:Traditional epidemiological studies suggest that there is an association between age at menarche (years) (AAM) and bone mineral density (BMD) at the sites of the femoral neck and lumbar spine (FNK and LS BMD), indicating a potentially important relationship between AAM and the development of osteoporosis (OP). However, these findings may be influenced by unmeasured confounding factors that can obscure the true relationship between the phenotypic traits. Therefore, we performed Mendelian randomization (MR) analyses to determine whether there is a causal relationship between AAM and BMD (FNK and LS BMD), where late AAM may increase the risk of developing OP. METHODS:Adopting a two-sample MR approach we incorporated genome-wide association (GWAS) summary statistics from the Reproductive Genetics (ReproGen) Consortium (n?=?182,416) (females only) and the GEnetic Factors for OSteoporosis (GEFOS) Consortium (n?=?53,236) (both males and females). RESULTS:Using this MR approach we discovered that each additional year in AAM is associated with a modest reduction in FNK BMD (??=?-0.072 se?=?0.022, 95% CI (-0.115, -0.030), p?=?0.001) and LS BMD ((??=?-0.072, se?=?0.025, 95% CI (-0.121, -0.023), p?=?0.004), and therefore influences OP susceptibility. CONCLUSIONS:This study demonstrates that AAM in females may play a causal role in OP etiology and provides novel insights into the pathophysiology of bone related diseases like osteoporosis, osteopenia and fracture. SUMMARY:Our study demonstrates that AAM in females may play a causal role in OP etiology and provides novel insights into the pathophysiology of bone related diseases like osteoporosis, osteopenia and fracture. By adopting Mendelian Randomization approaches, our study was not susceptible to bias from unmeasured confounders or reverse causation.
| S-EPMC6346741 | biostudies-literature
Project description:Observational studies suggest that cardiovascular disease (CVD) increases the risk of developing Alzheimer's disease (AD). However, the causal relationship between the two is not clear. This study applied a two-sample bidirectional Mendelian randomization method to explore the causal relationship between CVD and AD. Genome-wide association study (GWAS) data from 46 datasets of European populations (21,982 cases of AD and 41,944 controls) were utilized to obtain genetic instrumental variables for AD. In addition, genetic instrumental variables for atrial fibrillation (AF), heart failure (HF), myocardial infarction (MI), coronary heart disease (CHD), angina pectoris (AP), and ischemic stroke (IS) (including large-artery atherosclerotic stroke [LAS] and cardioembolic stroke [CES]) were selected from GWAS data of European populations (P < 5E-8). The inverse variance weighting method was employed as the major Mendelian randomization analysis method. Genetically predicted AD odds ratios (OR) (1.06) (95% CI: 1.02-1.10, P = 0.003) were linked to higher AP analysis. A higher genetically predicted OR for CES (0.9) (95% CI 0.82-0.99, P = 0.02) was linked to a decreased AD risk. This Mendelian randomized study identified AD as a risk factor for AP. In addition, CES was related to a reduced incidence of AD. Therefore, these modifiable risk factors are crucial targets for preventing and treating AD.
| S-EPMC10522384 | biostudies-literature
Project description:Alzheimer's disease (AD) manifests with a higher rate of occurrence in women. Previous epidemiological studies have suggested a potential association between AD and gynecological cancers, but the causal relationship between them remains unclear. This study aims to explore the causal link between 12 types of gynecological cancers and AD using a bidirectional Mendelian randomization (MR) approach. We obtained genetic correlation tools for AD using data from the most extensive genome-wide association study. Genetic correlation data for 12 types of gynecological cancers were also sourced from the Finnish Biobank. These cancers include breast cancer (BC), cervical adenocarcinoma (CA), cervical squamous cell carcinoma (CSCC), cervical cancer (CC), endometrial cancer (EC), ovarian endometrioid carcinoma (OEC), ovarian cancer (OC), ovarian serous carcinoma (OSC), breast carcinoma in situ (BCIS), cervical carcinoma in situ (CCIS), endometrial carcinoma in situ (ECIS), and vulvar carcinoma in situ (VCIS). We used the inverse-variance weighted (IVW) model for causal analysis and conducted horizontal pleiotropy tests, heterogeneity tests, MR-PRESSO tests, and leave-one-out analyses to ensure the robustness of our results. We also applied replication analysis and meta-analysis to further validate our experimental results. The study found that EC (P_IVW =0.037, OR [95% CI] = 1.032 [1.002, 1.064]) and CCIS (P_IVW = 0.046, OR [95% CI] = 1.032 [1.011, 1.064]) increase the risk of AD, whereas OC was negatively correlated with AD (P_IVW = 0.016, OR [95% CI] = 0.974[0.954, 0.995]). In reverse MR analysis, AD increased the risk of CC (P_IVW = 0.039, OR [95% CI] = 1.395 [1.017, 1.914]) and VCIS (P_IVW = 0.041, OR [95% CI] = 1.761 [1.027, 2.021]), but was negatively correlated with OEC (P_IVW = 0.034, OR [95% CI] = 0.634 [0.417, 0.966]). Sensitivity analysis results demonstrated robustness. These findings were further substantiated through replication and meta-analyses. Our MR study supports a causal relationship between AD and gynecological cancers. This encourages further research into the incidence of gynecological cancers in female Alzheimer's patients and the active prevention of AD.
| S-EPMC11337634 | biostudies-literature