Women's reproductive traits and major depressive disorder: A two-sample Mendelian randomization study

Deciphering the genetic interplay between depression and dysmenorrhea: a Mendelian randomization study

BACKGROUND

This study aims to explore the link between depression and dysmenorrhea by using an integrated and innovative approach that combines genomic, transcriptomic, and protein interaction data/information from various resources.

METHODS

A two-sample, bidirectional, and multivariate Mendelian randomization (MR) approach was applied to determine causality between dysmenorrhea and depression. Genome-wide association study (GWAS) data were used to identify genetic variants associated with both dysmenorrhea and depression, followed by colocalization analysis of shared genetic influences. Expression quantitative trait locus (eQTL) data were analyzed from public databases to pinpoint target genes in relevant tissues. Additionally, a protein-protein interaction (PPI) network was constructed using the STRING database to analyze interactions among identified proteins.

RESULTS

MR analysis confirmed a significant causal effect of depression on dysmenorrhea ['odds ratio' (95% confidence interval) = 1.51 (1.19, 1.91), P = 7.26 × 10-4]. Conversely, no evidence was found to support a causal effect of dysmenorrhea on depression (P = .74). Genetic analysis, using GWAS and eQTL data, identified single-nucleotide polymorphisms in several genes, including GRK4, TRAIP, and RNF123, indicating that depression may impact reproductive function through these genetic pathways, with a detailed picture presented by way of analysis in the PPI network. Colocalization analysis highlighted rs34341246(RBMS3) as a potential shared causal variant.

CONCLUSIONS

This study suggests that depression significantly affects dysmenorrhea and identifies key genes and proteins involved in this interaction. The findings underline the need for integrated clinical and public health approaches that screen for depression among women presenting with dysmenorrhea and suggest new targeted preventive strategies.

Causal relationship between Women's reproductive traits and postpartum depression: a multivariate mendelian randomization analysis

Purpose

The relationship between women's reproductive traits and postpartum depression (PPD) has not been clarified. We reveal the association between genetically predicted modifiable women's reproductive traits and PPD using two-sample Mendelian randomization (MR).

Methods

We used genome-wide association studies (GWASs) to obtain instrumental variables (IVs) of 9 women's reproductive traits. Univariate and multivariate MR analyses were used to examine the association between traits and the risk of PPD (13,657 cases and 236,178 controls). The primary causal effect assessment employed the IVW method. Heterogeneity was assessed using Cochran's Q test. Multiple horizontal effects were assessed using the MR-PRESSO and MR-Egger intercept. Leave-one-out and LASSO regression analyses were used to check the robustness of the UVMR and MVMR results, respectively.

Results

In the UVMR result, genetic prediction showed that age at first sexual intercourse (AFS) (OR = 0.474, 95% CI 0.396-0.567; p = 4.6 × 10-16), age at first birth (AFB) (OR = 0.865, 95% CI 0.805-0.930; p = 8.02 × 10-5), and age at last live birth (ALLB) (OR = 0.296, 95% CI 0.138-0.636; p = 0.002) were significantly inversely associated with PPD, while a higher lifetime number of sexual partners (LNSP) (OR = 1.431, 95% CI 1.009-2.031; p = 0.045) and a greater number of spontaneous miscarriages (OR = 1.519, 95% CI 1.021-2.262; p = 0.039) are suggested to be associated with an increased risk of PPD. In the MVMR result, only AFB (OR = 0.804, 95% CI 0.661-0.978; p = 0.029) retained a direct causative relationship with PPD.

Conclusion

The study indicates that AFB is a significant risk factor for PPD. Furthermore, the likelihood of developing PPD appears to decrease with increasing gestational age at the time of the first childbirth.

Associations between reproductive factors and the prevalence of depression: findings from the National Health and Nutrition Examination Survey (NHANES) 2005-2018

BACKGROUND

This study aims to explore the relationship between female reproductive factors (age at first birth (AFB), age at last birth (ALB), gravidity, and number of live birth (NLB)) and prevalence of depression among the US women.

METHODS

The relationship between AFB, ALB, gravidity, and NLB with the prevalence of depression was explored using publicly available data from the National Health and Nutrition Examination Survey 2005-2018. This cross-sectional study included female participants aged 20 years and older, with reproductive factors and depressive symptoms reported by the participants. Depression was evaluated using the Patient Health Questionnaire-9, with a score of ≥ 10 representing major depression disorder. Weighted multivariable logistic regression and restricted cubic splines (RCS) were utilized to explore the association of AFB, ALB, gravidity and NLB with depression.

RESULTS

In this study of 11,488 US women, 1,332 (11.6%) women had depression. Compared to the reference group of women with AFB under 18 years, the fully adjusted ORs and 95% CIs for depression were 0.83 (95% CI: 0.68-0.99), 0.75 (95% CI: 0.60-0.95), and 0.69 (95% CI: 0.51-0.93) for women with AFB of 21-23, 24-26, and 27-29 years, respectively. Furthermore, women with five or more pregnancies had a significantly higher prevalence of depression compared to those with two or fewer pregnancies (OR = 1.20, 95% CI: 1.01-1.42). RCS models demonstrated linear associations of ALB, gravidity and NLB with the prevalence of depression. Additionally, the RCS analysis revealed a roughly L-shaped relationship between AFB and prevalence of depression.

CONCLUSIONS

Women with later AFB are associated with a decreased prevalence of depression, while multiple pregnancies are associated with an increased prevalence of depression. These findings suggest that reproductive factors should be considered when screening for and developing preventive strategies for depression.

Health condition and socioeconomic status mediate the causal effect of reproductive traits on nonalcoholic fatty liver disease: evidence from Mendelian randomization study

Background

Observational data posits a correlation between reproductive traits and nonalcoholic fatty liver disease (NAFLD), but their causal inference is still unclear. This investigation seeks to elucidate the causal influence of reproductive traits on NAFLD and determine the intervening role of health condition and socioeconomic status in these connections.

Methods

Utilizing a Mendelian Randomization (MR) approach, this research leveraged a comprehensive dataset from the Genome-wide Association Study (GWAS) database. The study incorporated body mass index, major depression, educational level, household income and Townsend deprivation index as intermediary variables. Initially, a bidirectional two-sample MR study was conducted to explore the genetic associations between reproductive traits and NAFLD. Then, two-step MR analyses were implemented to quantify the extent of mediation by these indicators. The weighted inverse variance method was the primary analytical approach, complemented by several sensitivity analyses to affirm the robustness of the MR assumptions. Finally, these findings were validated in the FinnGen research.

Results

The bidirectional MR analysis indicated that earlier reproductive traits (age at menarche, age at first sexual intercourse, and age at first birth) were associated with an elevated risk of NAFLD, absent any evidence of the reverse relationship. Body mass index accounted for 35.64% of the association between premature menarche and NAFLD. Additionally, body mass index, major depression, educational level and household income mediated 41.65%, 14.35%, 37.88%, and 18.59% of the connection between early sexual intercourse and NAFLD, respectively. Similarly, these same variables elucidated 36.36%, 15.58%, 41.56%, and 22.73% of the correlation between younger age at first birth and NAFLD.

Conclusion

Our study elucidated the causal relationships between reproductive traits and NAFLD. Potential underlying mechanisms may involve factors such as body mass index, major depression, educational attainment and household income.

Mendelian randomization analyses for the causal relationship between early age at first sexual intercourse, early age at first live birth, and postpartum depression in pregnant women

Introduction

There are insufficient epidemiological studies on the impact of age at first sexual intercourse (AFS) and age at first live birth (AFB) on postpartum depression (PPD) in pregnant women, and the conclusions of these studies are inconsistent.

Methods

We performed a Mendelian randomization (MR) study to determine the causal relationship between AFS or AFB and the risk of PPD. The summary data were extracted from genome-wide association study (GWAS) summary datasets. We selected the instrumental variables according to the P value of exposure-related single nucleotide polymorphisms (P<5 ×10-9 for AFS and P<5 ×10-8 for AFB) and estimated the linkage disequilibrium using the clump parameter (10,000 kb, r2 < 0.001). Single nucleotide polymorphisms were considered instrumental variables that were significantly associated with exposure factors without linkage disequilibrium. The F-statistics of the instrumental variables should all be larger than 10. A random-effects model of IVW was constructed as the main method in our study.

Results and discussion

MR studies based on GWAS data revealed that both AFS (OR = 0.4, P <0.001) and AFB (OR = 0.38, P <0.001) were negatively correlated with the risk of PPD. Early AFS and early AFB should be studied as possible risk factors for PPD in the future. Public health departments should attach importance to sex education for young girls. The results of our TSMR should be verified by high-quality prospective epidemiological studies in the future.

Causal analysis of gastroesophageal reflux disease and esophageal cancer

Patients with gastroesophageal reflux disease (GERD) are more likely to develop esophageal cancer (EC). However, a causal relationship between the 2 has been difficult to determine. Therefore, this study aimed to evaluate the impact of GERD on EC using the Mendelian randomization (MR) method. The causal association between GERD and EC was analyzed based on 2 publicly available genetic summary datasets for the GERD cohort (129,080 cases vs 473,524 controls) and the EC cohort (740 cases vs 372,016 controls). The causal inference was mainly evaluated by the inverse variance weighted MR. The MR-Egger regression, MR Pleiotropy Residual Sum and Outlier test, and leave-one-out test were used to confirm the sensitivity of the MR results. Possible interfering factors were excluded by multivariate MR (MVMR) analysis. We used 73 single nucleotide polymorphisms as instrumental variables. GERD was associated with increasing EC risk (odds ratio [OR], 1.001; 95% confidence interval, 1.001-1.002; P < .001), which was identified using the inverse variance weighted method. The sensitivity analysis also demonstrated similar results with the causal explanation, and major bias in genetic pleiotropy was not identified (intercept, 0.001; standard error, 0.001; P = .418). The multivariate MR analysis demonstrated the effect of GERD on EC even after excluding possible mediating factors (OR, 1.003; 95% confidence interval, 1.001-1.005; P = .012). This study confirmed that GERD has a causal effect on EC. Therefore, interventional measures are recommended to prevent EC.

Identifying causal associations between women's reproductive traits and risk of schizophrenia: a multivariate validated two-sample Mendelian randomization analysis

BACKGROUND

A significant association between women's reproductive traits and the risk of schizophrenia (SCZ) has been discovered, but the causalities remain unclear. We designed a two-sample univariate Mendelian randomization (MR) study using female-specific SNPs collected from a large-scale genome-wide association study as a genetic tool to explore the causal effect of female reproductive traits on the risk of SCZ, and conducted a multivariate MR study to re-validate the above findings.

METHODS

From extensive genome-wide association studies (GWAS) of people with European ancestry (n = 176,881 to 418,758 individuals), summary-level data on five female reproductive variables were extracted. Summary-level information on SCZ was taken from a GWAS meta-analysis involving 320,404 people with European ancestry. The inverse variance weighting estimations for both univariable MR (UVMR) and multivariable MR (MVMR) were presented as the primary results. MR-Egger, weighted median, simple mode, and weighted mode regression methods for UVMR, and MVMR-Egger, MVMR-Lasso, and MVMR-median methods for MVMR were used for sensitivity analyses.

RESULTS

The UVMR produced compelling proof for a connection between genetically predicted later age at first sexual intercourse (AFS) (OR, 0.632; 95% CI, 0.512-0.777; P < 0.01) and decreased SCZ risk. Pleiotropy analysis of the AFS-SCZ association confirmed the robustness of the MR results (P > 0.05). Consistent, substantial causal effects of AFS (OR, 0.592; 95%CI, 0.407-0.862; P < 0.01) on the risk of SCZ were demonstrated after adjusting for body mass index, years of schooling, and smoking initiation using MVMR.

CONCLUSIONS

Our findings provide convincing evidence that early AFS is a risk factor for SCZ. SCZ risk may be decreased by raising awareness of reproductive healthcare for women.

Mendelian randomization and colocalization analyses reveal an association between short sleep duration or morning chronotype and altered leukocyte telomere length

Observational studies suggest certain sleep traits are associated with telomere length, but the causal nature of these associations is unclear. The study aimed to determine the causal associations between 11 sleep-related traits and leukocyte telomere length (LTL) through two-sample Mendelian randomization and colocalization analyses using the summary statistics from large-scale genome-wide association studies. Univariable Mendelian randomization indicates that genetically determined short sleep is associated with decreased LTL, while morning chronotype is associated with increased LTL. Multivariable Mendelian randomization further supports the findings and colocalization analysis identifies shared common genetic variants for these two associations. No genetic evidence is observed for associations between other sleep-related traits and LTL. Sensitivity MR methods, reverse MR and re-running MR after removing potential pleiotropic genetic variants enhance the robustness of the results. These findings indicate that prioritizing morning chronotype and avoiding short sleep is beneficial for attenuating telomere attrition. Consequently, addressing sleep duration and chronotype could serve as practical intervention strategies.

Identifying causal associations between early sexual intercourse or number of sexual partners and major depressive disorders: A bidirectional two-sample Mendelian randomization analysis

BACKGROUND

Early sexual intercourse and a greater number of sexual partners have been proved associated with depression. However, the causality of these associations is not clear.

METHODS

To unveil the causal associations between sexual factors and major depression disorder (MDD). The bidirectional, two-sample Mendelian randomization (MR) study was conducted, which used genetic variants associated with two sexual factors (age first had sexual intercourse, n = 406,457; lifetime number of sexual partners, n = 378,882) and MDD (n = 500,199) from the largest genome-wide association studies (GWASs) conducted by the UK biobank and the Psychiatric Genomics Consortium. The two-step MR analysis was applied to assess mediation. The Genetic predictors for five risky behaviors were also obtained from the most up-to-date GWAS conducted by the UK Biobank (ever self-harmed: 117,733; ever attempted suicide: 4933; psychoactive substance abuse, alcohol use, and tobacco use: 463,010).

RESULTS

MR analysis indicated a risky causal effect of age first had sexual intercourse (OR = 0.720, 95 % CI: 0.661-0.784, P = 2.45 × 10^-14) and lifetime number of sexual partners (OR = 1.656, 95 % CI: 1.356-2.022, P = 7.46 × 10^-7) on MDD. Mediation analysis showed the effects were mediated by tobacco use, with a proportion of 34.20 % on age first had sexual intercourse and 22.94 % on lifetime number of sexual partners separately.

LIMITATIONS

The overlap of participants in different traits and unclear gender.

CONCLUSIONS

Robust genetic evidence indicated that premature sexual intercourse and more sexual partners were risks for MDD. Risky behaviors, especially the tobacco use, mediated this effect.