Socioeconomic Status, Individual Behaviors and Risk for Mental Disorders: A Mendelian Randomization Study

NSAID medication mediates the causal effect of genetically predicted major depressive disorder on falls: Evidence from a Mendelian randomization study

BACKGROUND

Increasing evidence supports that depression including major depressive disorder (MDD) is associated with an increased risk of falls. However, some studies suggest no association between MDD and falls. Therefore, the specific causal relationship whereby MDD affects the risk of falls remains elusive, and the potential mediators are unclear.

METHODS

Summary-level data for MDD and falls were collected from the Genome-wide association studies (GWAS) in this study. Mendelian randomization (MR) and multivariable MR (MVMR) analyses were performed to evaluate the causal associations between MDD and falls. A Two-step MR analysis was employed to analyze the mediating effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the causal association between MDD and the risk of falls.

RESULTS

Using the inverse-variance weighted (IVW) method, genetically predicted MDD was associated with an increased risk of falls (β = 0.15, SE = 0.034; P = 1.61E-5). MVMR and two-step MR analyses demonstrated that MDD was a causal determinant of increased falls independent of body mass index (BMI), smoking initiation, and alcohol consumption and that this causal relationship was mediated by NSAID medication.

LIMITATIONS

Extracted GWAS summary statistics are from European ancestry. Stratified analyses by sex and age were not included in our study. Therefore, it is unclear whether the results are the same for other ethnic groups, genders, and ages.

CONCLUSIONS

Our results demonstrate that MDD is independently associated with an increased risk of falls, in which NSAIDs mediate the association. This study suggests that avoiding the use of NSAIDs may reduce the risk of falls in patients diagnosed with MDD.

Causal effect of the age at first birth with depression: a mendelian randomization study

BACKGROUND

This study aimed to explore the causal relationship between age at first birth (AFB) and depression.

METHODS

Using the univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) methods to examine the potential correlation between age at first birth (AFB) and major depressive disorder and postpartum depression. A public database was used to obtain the genome-wide association studies (GWAS) summary data. We put inverse-variance-weighted (IVW) as the primary method in Mendelian randomization (MR) analysis and used sensitivity analysis to confirm the robustness of our result.

RESULTS

We found a significant causal association between AFB and major depressive disorder by using the IVW algorithm (odd ratio [OR] 0.826; 95% confidence interval [CI] 0.793 - 0.861; P = 4.51 × 10- 20). MR-Egger, weighted median, simple mode and weighted mode method concluded the same result (P < 0.05). During the sensitivity analysis, the heterogeneity test (Q-value = 55.061, df = 48, P = 2.81 × 10- 01, I2 = 12.82%) and the leave-one-out plot analysis confirmed the stability of the results. The outcomes of the pleiotropy test (MR-Egger intercept = 8.932 × 10- 3. SE = 6.909 × 10- 3. P = 2.02 × 10- 01) and MR_PRESSO global test (P = 2.03 × 10- 01) indicated there is no pleiotropy.

CONCLUSION

There is solid evidence that a higher age at first birth is associated with a lower risk of major depressive disorder.

Birth Weight and Risk of Cerebral Aneurysm: A Multivariable Mendelian Randomization Study

BACKGROUND

Birth weight has been linked with various health outcomes. The association between birth weight and cerebral aneurysm remains unknown.

METHODS

The two-sample Mendelian randomization (MR) approach was used to evaluate the causal effect of birth weight on cerebral aneurysm based on genome-wide association studies (GWAS), comprising 261,932 UKB participants for birth weight and 204,060 FinnGen participants for cerebral aneurysm. The inverse variance weighted (IVW) method was used as the primary method. Alternative methods were used for comparison. Sensitivity analysis was conducted to evaluate the robustness of the results. Multivariable MR (MVMR) was further conducted to evaluate the direct effect of the birth weight on cerebral aneurysm.

RESULTS

The IVW detected a causal association between higher birth weight and increased risk of cerebral aneurysm (OR = 0.521, 95% CI = 0.356 ∼ 0.763, P = 7.88 × 10-4), which was supported by alternative MR models. Sensitivity analysis did not find any evidence of heterogeneity or pleiotropy. MVMR further identified a direct effect of birth weight on cerebral aneurysm, independent of obesity-related traits or smoking.

CONCLUSION

This MR study found evidence of the association between birth weight and cerebral aneurysm, providing novel insight into the etiology of cerebral aneurysm, indicating the promising role of birth weight as a marker for screening populations at higher risk of cerebral aneurysm.

Associations of Socioeconomic Status Inequity with Incident Age-related Macular Degeneration in Middle-Aged and Elderly Population

Background: The relationship between socioeconomic status (SES) inequity and incident age-related macular degeneration (AMD) remains unclear. We aim to investigate whether low SES increases the risk of AMD and to explore the effect of a healthy lifestyle on this association. Methods: This prospective cohort study included 316,663 UK Biobank individuals. SES inequity was identified via latent class analysis using education, household income, and occupational status. Healthy lifestyle score was calculated based on smoking, alcohol drinking, and physical activity (PA). Incident AMD was defined according to diagnosis records. Cox proportional hazards models were used to evaluate the relationship of low SES and AMD. Interrelationships of healthy lifestyle score on SES-AMD association were explored, including modification, mediation, and joint effects. Results: During the average 12.2 years of follow-up, 6,355 AMD cases were diagnosed. Participants with medium SES (hazard ratio: 1.10 [95% confidence interval (CI) 1.01 to 1.21]) and low SES (hazard ratio: 1.22 [95% CI 1.11 to 1.34]) had an increased risk of incident AMD compared to participants with high SES. PA significantly affected this association. Moreover, the association between low SES and AMD was significantly mediated (11.3%, 95% CI: 6.56 to 23.0) by smoking. Similarly, alcohol drinking suppressed (9.59%, 95% CI: 4.00 to 23.2) the association between high SES and AMD. Besides, a significant joint effect of SES and healthy lifestyle score was found. Conclusions: We provide further evidence for the relationship of socioeconomic inequity, healthy lifestyle, and incident AMD. Future public health strategies should aim to reduce socioeconomic inequity to prevent AMD.

Body mass index, smoking behavior, and depression mediated the effects of schizophrenia on chronic obstructive pulmonary disease: trans-ethnic Mendelian-randomization analysis

Background

Previous studies have highlighted the association between schizophrenia (SCZ) and chronic obstructive pulmonary disease (COPD), yet the causal relationship remains unestablished.

Methods

Under the genome-wide significance threshold (P<5×10-8), data from individuals of European (EUR) and East Asian (EAS) ancestries with SCZ were selected for analysis. Univariable Mendelian randomization (MR) explored the causal relationship between SCZ and COPD. Linkage disequilibrium score (LDSC) regression was used to calculate genetic correlation, while multivariable and mediation MR further investigated the roles of six confounding factors and their mediating effects. The primary method utilized was inverse-variance weighted (IVW), complemented by a series of sensitivity analyses and false discovery rate (FDR) correction.

Results

LDSC analysis revealed a significant genetic correlation between SCZ and COPD within EUR ancestry (rg = 0.141, P = 6.16×10-7), with no such correlation found in EAS ancestry. IVW indicated a significant causal relationship between SCZ and COPD in EUR ancestry (OR = 1.042, 95% CI 1.013-1.071, P = 0.003, PFDR = 0.015). Additionally, replication datasets provide evidence of consistent causal associations(P < 0.05 & PFDR < 0.05). Multivariable and mediation MR analyses identified body mass index (BMI)(Mediation effect: 50.57%, P = 0.02), age of smoking initiation (Mediation effect: 27.42%, P = 0.02), and major depressive disorder (MDD) (Mediation effect: 60.45%, P = 6.98×10-5) as partial mediators of this causal relationship. No causal associations were observed in EAS (OR = 0.971, 95% CI 0.875-1.073, P = 0.571, PFDR = 0.761) ancestry. No causal associations were found in the reverse analysis across the four ancestries (P > 0.05 & PFDR > 0.05).

Conclusions

This study confirmed a causal relationship between SCZ and the risk of COPD in EUR ancestry, with BMI, smoking, and MDD serving as key mediators. Future research on a larger scale is necessary to validate the generalizability of these findings across other ancestries.

Socioeconomic status, individual behaviors and risk for Lymphomas: a Mendelian randomization study

Background: The association of socioeconomic status and individual behavior (SES/IB) with human health is receiving increasing attention. However, the causal effects between SES/IB and lymphomas remain unclear. Methods: A two-sample Mendelian randomization (MR) study was used to assess the causal effects of 25 SES/IB traits (dietary habits, physical activity, smoking/drinking behaviors, sleeping behaviors, leisure sedentary behaviors, risky behaviors, and reproductive behaviors) on six distinct types of lymphomas, including Hodgkin lymphoma (HL), follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), mature T/NK-cell lymphomas, marginal zone B-cell lymphoma (MZL), and mantle cell lymphoma (MCL). The inverse variance weighted (IVW) method was the primary approach used for the MR analysis. A series of sensitivity analyses were also conducted to ensure the robustness of the findings. Results: Two-sample MR revealed six SES/IB traits causally associated with lymphomas, including relative fat intake, drive time, television watching time, computer use time, vigorous physical activity, and number of children ever born. After false discovery rate (FDR) correction, the causal associations between longer television watching time and DLBCL (OR: 4.048, 95% CI: 1.688 to 9.708, P fdr=0.009), and the number of children ever born with both FL (OR: 0.008, 95% CI: 1.412E-04 to 0.484, P fdr=0.021) and DLBCL (OR: 0.001, 95% CI:1.587E-05 to 0.081, P fdr=0.002) were identified. Conclusions: These findings suggest that certain lifestyle and behavioral factors have a measurable impact on specific lymphoma types.

The Humanistic and Economic Burden Associated with Major Depressive Disorder: A Retrospective Cross-Sectional Analysis

INTRODUCTION

Major depressive disorder (MDD) is a debilitating and costly condition. This analysis characterized the health-related quality of life (HRQoL), health care resource utilization (HCRU), and costs between patients with versus without MDD, and across MDD severity levels.

METHODS

The 2019 National Health and Wellness Survey was used to identify adults with MDD, who were stratified by disease severity (minimal/mild, moderate, moderately severe, severe), and those without MDD. Outcomes included HRQoL (Short Form-36v2 Health Survey, EuroQol Five-Dimension Visual Analogue Scale, utility scores), HCRU (hospitalizations, emergency department [ED] visits, health care provider [HCP] visits), and annualized average direct medical and indirect (workplace) costs. A subgroup analysis was conducted in participants with MDD and prior medication treatment failure. Participant characteristics and study outcomes were evaluated using bivariate analyses and multivariable regression models, respectively.

RESULTS

Cohorts comprised 10,710 participants with MDD (minimal/mild = 5905; moderate = 2206; moderately severe = 1565; severe = 1034) and 52,687 participants without MDD. Participants with MDD had significantly lower HRQoL scores than those without (each comparison, P < 0.001). Increasing MDD severity was associated with decreasing HRQoL. Relative to participants without MDD, participants with MDD reported more HCP visits (2.72 vs 5.64; P < 0.001) and ED visits (0.18 vs 0.22; P < 0.001) but a similar number of hospitalizations. HCRU increased with increasing MDD severity. Although most patients with MDD had minimal/mild to moderate severity, total direct medical and indirect costs were significantly higher for participants with versus without MDD ($8814 vs $6072 and $5425 vs $3085, respectively, both P < 0.001). Direct and indirect costs were significantly higher across all severity levels versus minimal/mild MDD (each comparison, P < 0.05). Among patients with prior MDD medication treatment failure (n = 1077), increasing severity was associated with significantly lower HRQoL and higher total indirect costs than minimal/mild MDD.

CONCLUSION

These results quantify the significant and diverse burdens associated with MDD and prior MDD medication treatment failure.

Socioeconomic status, personality, and major mental disorders: a bidirectional Mendelian randomization study

Previous research has suggested a correlation between socioeconomic status (SES) and mental diseases, while personality traits may be associated with SES and the risk of mental disorders. However, the causal nature of these associations remains largely uncertain. Our Mendelian randomization (MR) study aims to explore the bidirectional causality between SES and mental disorders, as well as to evaluate the potential mediating role of personality in these associations. Using bidirectional MR approach, we assessed the causality between SES indicators and mental disorders. We then used a two-step MR method to further investigate whether and to what extent personality mediates the causal associations in Caucasians. The forward MR analyses identified that years of education, household income, age at first birth and the Townsend deprivation index had a causal association with at least one mental disorder. The reverse MR analyses identified causal effects of genetically predicted schizophrenia, bipolar disorder, and attention deficit/hyperactivity disorder on five SES indicators. Importantly, mediation analysis showed that neuroticism partly mediated the causality of household income and years of education on major depressive disorder, respectively. In brief, our study confirmed the bidirectional relationship between SES and mental disorders. We also revealed the role of neuroticism in mediating the association between SES and major depressive disorder, highlighting the importance of considering both socioeconomic and personality factors in mental health research and interventions.

The causal impact of maternal smoking around birth on offspring ADHD: A two-sample Mendelian randomization study

BACKGROUND

The previous literature highlights a relationship between maternal smoking around birth (MSAB) and offspring attention-deficit/hyperactivity disorder (ADHD). These studies have focused on the causal effects of MSAB on offspring ADHD.

METHOD

A Mendelian randomization analysis was conducted using summary statistics. Data on MSAB were obtained from a recent study including 391,992 participants. ADHD data were obtained from six sources for 246,888 participants. The present study used five methods to examine the causal impact from outcomes on exposures. The inverse variance weighted (IVW) was the main method of analysis, while the other four methods were supplementary methods.

RESULT

The IVW revealed that MSAB was a risk factor for offspring ADHD (OR: 2.54; 95 % confidence interval [CI]: 1.61-4.00, p = 6.04 × 10-5). Concerning ADHD in both sexes, MSAB was associated with females (OR = 3.96, 95 % CI: 1.99-7.90, p = 8.98 × 10-5) and males (OR = 3.74, 95 % CI: 1.74-5.72, p = 1.48 × 10-4). In different diagnosis periods for ADHD, MSAB increased the risk of childhood (OR = 3.63, 95 % CI: 2.25-5.87, p = 1.31 × 10-7), late-diagnosed (OR = 2.99, 95 % CI: 1.74-5.14, p = 7.33 × 10-5), and persistent (OR = 4.77, 95 % CI: 1.88-12.14, p = 1.03 × 10-3) ADHD. The final analysis did not reveal heterogeneity.

CONCLUSIONS

A causal impact of MSAB on offspring ADHD was observed. These findings highlight the need for careful consideration of prenatal exposure (MSAB) during the assessment of offspring ADHD. Additionally, it can provide targeted guidance for prenatal interventions. Future studies should analyze the effects of different doses of maternal smoking on ADHD.

Causal association between gut microbiomes and different types of aneurysms: a Mendelian randomization study

Background

Previous studies suggests that gut microbiomes are associated with the formation and progression of aneurysms. However, the causal association between them remains unclear.

Methods

A two-sample Mendelian randomization was conducted to investigate whether gut microbiomes have a causal effect on the risk of intracerebral aneurysm (IA), thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA), and aortic aneurysm (AA). Single nucleotide polymorphisms (SNPs) smaller than the locus-wide significance level (1 × 10-5) were selected as instrumental variables. We used inverse-variance weighted (IVW) test as the primary method for the evaluation of causal association. MR-Egger, weighted median, weighted mode, and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO) methods were conducted for sensitive analysis. The p-value was adjusted by the false discovery rate (FDR) which adjust the results of multiple comparisons, a p < 0.05 and q < 0.1 was considered a significant causal association. Additionally, a p < 0.05 and q > 0.1 was considered a suggestive causal effect. Additionally, reverse MR was also performed to exclude the possibility of reverse causality.

Results

The phylum Firmicutes (OR = 0.62; 95% CI, 0.48-0.81), class Lentisphaeria (OR = 0.75; 95% CI, 0.62-0.89), and order Victivallales (OR = 0.75; 95% CI, 0.62-0.89) have a causal protective effect on the risk of AAA. Additionally, class Verrucomicrobia, class Deltaproteobacteria, order Verrucomicrobiale, family Verrucomicrobiacea, genus Eubacterium rectale group, genus Akkermansia, and genus Clostridium innocuum group were negatively associated with the risk of different types of aneurysms, whereas class Negativicutes, order Selenomonadales, and genus Roseburia had positive causal association with different types of aneurysms (p < 0.05; q > 0.1). Further sensitivity analysis validated the robustness of our MR results, and no reverse causality was found with these gut microbiomes (p > 0.05).

Conclusion

Our MR analysis confirmed the causal association of specific gut microbiomes with AAA, and these microbiomes were considered as protective factors. Our result may provide novel insights and theoretical basis for the prevention of aneurysms through regulation of gut microbiomes.

Associations between benign paroxysmal positional vertigo and seven mental disorders: a two-sample Mendelian randomization study

Background

The association between benign paroxysmal positional vertigo (BPPV) and various mental disorders is still controversial. This study used the Mendelian randomization (MR) method to clarify the correlation between BPPV and seven mental disorders (bipolar disorder, depression, anxiety disorder, schizophrenia, suicidality, neuroticism, and mood swings) to aid in the exploration of BPPV complications and prevention and early treatment of mental disorders.

Methods

The datasets for BPPV and seven mental disorders were obtained from genome-wide association studies (GWASs). Two-sample MR was used to analyze the correlation between exposure (BPPV) and various outcomes (bipolar disorder, depression, anxiety disorder, schizophrenia, suicidality, neuroticism, and mood swings). A reverse MR study was also performed. The inverse variance weighting (IVW) method, the MR-Egger method, the simple mode method, the weighted mode method, and the weighted median method were selected.

Results

The MR analysis and the reverse MR analysis results did not reveal significant associations between BPPV and bipolar disorder, depression, anxiety disorder, schizophrenia, suicidal tendencies, neuroticism, and mood swings. Interestingly, neuroticism (IVW: OR = 1.142, 95% CI: 1.059-1.231, P = 0.001; P-MR-PRESSO adjustment = 0.0002) and mood swings (IVW: OR = 3.119, 95% CI: 1.652-5.884, P = 0.0004) may have a significant association with BPPV. After MR-PRESSO adjustment, there was no horizontal pleiotropy or heterogeneity, and a significant association between neuroticism, mood swings, and BPPV has still been suggested.

Conclusion

We conducted MR analysis on genetic data from European populations and discovered a causal relationship between BPPV and the seven mental disorders. Our research findings suggest that BPPV may not have a significant causal relationship with bipolar disorder, depression, anxiety disorder, schizophrenia, or suicidal tendencies. However, neuroticism and mood swings may be risk factors for BPPV.

Blood metabolites mediate the impact of lifestyle factors on the risk of urolithiasis: a multivariate, mediation Mendelian randomization study

Urolithiasis is closely linked to lifestyle factors. However, the causal relationship and underlying mechanisms remain unclear. This study aims to investigate the relationship between lifestyle factors and the onset of urolithiasis and explore potential blood metabolite mediators and their role in mediating this relationship. In this study, we selected single nucleotide polymorphisms (SNPs) as instrumental variables if they exhibited significant associations with our exposures in genome-wide association studies (GWAS) (p < 5.0 × 10-8). Summary data for urolithiasis came from the FinnGen database, including 8597 cases and 333,128 controls. We employed multiple MR analysis methods to assess causal links between genetically predicted lifestyle factors and urolithiasis, as well as the mediating role of blood metabolites. A series of sensitivity and pleiotropy analyses were also conducted. Our results show that cigarettes smoked per day (odds ratio [OR] = 1.159, 95% confidence interval [CI] = 1.004-1.338, p = 0.044) and alcohol intake frequency (OR = 1.286, 95% CI = 1.056-1.565, p = 0.012) were positively associated with increased risk of urolithiasis, while tea intake (OR = 0.473, 95% CI = 0.299-0.784, p = 0.001) was positively associated with reduced risk of urolithiasis. Mediation analysis identifies blood metabolites capable of mediating the causal relationship between cigarettes smoked per day, tea intake and urolithiasis. We have come to the conclusion that blood metabolites serve as potential causal mediators of urolithiasis, underscoring the importance of early lifestyle interventions and metabolite monitoring in the prevention of urolithiasis.

Schizophrenia and Types of Stroke: A Mendelian Randomization Study

BACKGROUND

Previous studies suggest an association between schizophrenia and stroke, but no studies have investigated stroke subtypes. We examined potential causal associations between schizophrenia and a range of atherosclerotic, embolic, and hemorrhagic stroke outcomes.

METHODS AND RESULTS

Two-sample Mendelian randomization analyses were conducted. The summary-level data (restricted to European ancestry) were obtained for schizophrenia and stroke: ischemic stroke, large-artery stroke, small-vessel stroke, cardioembolic stroke, and intracerebral hemorrhage. The associations between schizophrenia and each outcome were analyzed by an inverse variance weighting method primarily and Mendelian randomization Egger, weighted median, and weighted mode subsequently. The presence of pleiotropy was also tested by Cochran Q statistic, I2 index, and Mendelian randomization Egger intercept with scatter and funnel plots. We found associations between schizophrenia and cardioembolic stroke (odds ratio [OR], 1.070 [95% CI, 1.023-1.119]) and intracerebral hemorrhage (OR, 1.089 [95% CI, 1.005-1.180]) using inverse variance weighting. Little evidence of associations with the other stroke subtypes was found. Different Mendelian randomization methods corroborated the association with cardioembolic stroke but not intracerebral hemorrhage.

CONCLUSIONS

We have provided evidence of a potentially causal association between schizophrenia and cardioembolic stroke. Our findings suggest that cardiac evaluation should be considered for those with schizophrenia.

Determinants and outcomes of health-promoting lifestyle among people with schizophrenia

BACKGROUND

Healthy lifestyle is an important protective factor of developing cardiovascular disease in people with schizophrenia. However, little is known about the determinants of lifestyle and its contribution to metabolic syndrome. This study aimed to explore the influencing factors of health-promoting lifestyle (HPL) and its association with metabolic syndrome among people with schizophrenia.

METHODS

A cross-sectional study was conducted in twenty-two primary health centers of Guangzhou, China between December 2022 and April 2023. A total of 538 patients with schizophrenia were recruited through convenience sampling. Self-administered scales, questionnaires, and clinical data were collected. Scales and questionnaires included social-demographic information, Health-Promoting Lifestyles Profile (HPLP-C), UCLA Loneliness Scale (ULS), and International Physical Activity Questionnaire-Short Form (IPAQ-SF). Cluster analyses were used to divide participants into two groups based on the distribution characteristics of HPLP-C scores. Logistic regression models were used to identify factors associated with HPL and the association between HPL and metabolic syndrome.

RESULTS

There were 271 participants in the high HPL group and 267 participants in the low HPL group. Logistic regression analysis revealed that loneliness posed a risk factor for high HPL, while high education and moderate-vigorous physical activity served as protective factors for high HPL. Low HPL was a risk factor for the prevalence of metabolic syndrome.

CONCLUSIONS

Promotion of high education literacy and a physically active lifestyle should be priority targets in the health management of schizophrenia. Primary healthcare providers can play a pivotal role in assisting patients to mitigate metabolic syndrome by reinforcing healthy lifestyle strategies.

Exploring the influences of education, intelligence and income on mental disorders

Background

Previous studies have shown that educational attainment (EA), intelligence and income are key factors associated with mental disorders. However, the direct effects of each factor on major mental disorders are unclear.

Aims

We aimed to evaluate the overall and independent causal effects of the three psychosocial factors on common mental disorders.

Methods

Using genome-wide association study summary datasets, we performed Mendelian randomisation (MR) and multivariable MR (MVMR) analyses to assess potential associations between the 3 factors (EA, N=766 345; household income, N=392 422; intelligence, N=146 808) and 13 common mental disorders, with sample sizes ranging from 9907 to 807 553. Inverse-variance weighting was employed as the main method in the MR analysis.

Results

Our MR analysis showed that (1) higher EA was a protective factor for eight mental disorders but contributed to anorexia nervosa, obsessive-compulsive disorder (OCD), bipolar disorder (BD) and autism spectrum disorder (ASD); (2) higher intelligence was a protective factor for five mental disorders but a risk factor for OCD and ASD; (3) higher household income protected against 10 mental disorders but confers risk for anorexia nervosa. Our MVMR analysis showed that (1) higher EA was a direct protective factor for attention-deficit/hyperactivity disorder (ADHD) and insomnia but a direct risk factor for schizophrenia, BD and ASD; (2) higher intelligence was a direct protective factor for schizophrenia but a direct risk factor for major depressive disorder (MDD) and ASD; (3) higher income was a direct protective factor for seven mental disorders, including schizophrenia, BD, MDD, ASD, post-traumatic stress disorder, ADHD and anxiety disorder.

Conclusions

Our study reveals that education, intelligence and income intertwine with each other. For each factor, its independent effects on mental disorders present a more complex picture than its overall effects.

Causal Roles of Lifestyle, Psychosocial Characteristics, and Sleep Status in Sarcopenia: A Mendelian Randomization Study

BACKGROUND

Many studies reported that lifestyle, psychosocial characteristics, and sleep status related to sarcopenia, although few studies provided evidence of causal relationships between them.

METHODS

The data used in our study were from UK Biobank, FinnGen Release 8, and large genome-wide association study meta-analyses. Two-sample Mendelian randomization was conducted to identify the causal associations of 21 traits of lifestyle, psychosocial characteristics, and sleep status with 6 traits of sarcopenia. Benjamini-Hochberg correction was performed to reduce the bias caused by multiple tests. Risk factor analyses were performed to explore the potential mechanism behind the exposures.

RESULTS

Mendelian randomization analyses after adjustment proved the causal roles of coffee intake, education years, smoking, leisure screen time, and moderate-to-vigorous intensity physical activity during leisure time in sarcopenia was proven although providing no significant evidence for causal roles for carbohydrates intake, protein intake, alcohol, and sleep status in sarcopenia.

CONCLUSIONS

Our results strongly support that coffee intake, education years, smoking, leisure screen time, and moderate-to-vigorous intensity physical activity during leisure time played significantly causal roles in sarcopenia, which may provide new intervention strategies for preventing the development of sarcopenia.

Causal effects of potential risk factors on postpartum depression: a Mendelian randomization study

Background

Postpartum depression (PPD) is a type of depressive episode related to parents after childbirth, which causes a variety of symptoms not only for parents but also affects the development of children. The causal relationship between potential risk factors and PPD remains comprehensively elucidated.

Methods

Linkage disequilibrium score regression (LDSC) analysis was conducted to screen the heritability of each instrumental variant (IV) and to calculate the genetic correlations between effective causal factors and PPD. To search for the causal effect of multiple potential risk factors on the incidence of PPD, random effects of the inverse variance weighted (IVW) method were applied. Sensitivity analyses, including weighted median, MR-Egger regression, Cochrane's Q test, and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO), were performed to detect potential Mendelian randomization (MR) assumption violations. Multivariable MR (MVMR) was conducted to control potential multicollinearity.

Results

A total of 40 potential risk factors were investigated in this study. LDSC regression analysis reported a significant genetic correlation of potential traits with PPD. MR analysis showed that higher body mass index (BMI) (Benjamini and Hochberg (BH) corrected p = 0.05), major depression (MD) (BH corrected p = 5.04E-19), and schizophrenia (SCZ) (BH corrected p = 1.64E-05) were associated with the increased risk of PPD, whereas increased age at first birth (BH corrected p = 2.11E-04), older age at first sexual intercourse (BH corrected p = 3.02E-15), increased average total household income before tax (BH corrected p = 4.57E-02), and increased years of schooling (BH corrected p = 1.47E-11) led to a decreased probability of PPD. MVMR analysis suggested that MD (p = 3.25E-08) and older age at first birth (p = 8.18E-04) were still associated with an increased risk of PPD.

Conclusion

In our MR study, we found multiple risk factors, including MD and younger age at first birth, to be deleterious causal risk factors for PPD.

Socioeconomic status, obesity, individual behaviors, diabetes, and risk for frozen shoulder: A Mendelian randomization study

There are few studies on risk factors for frozen shoulder, and even fewer Mendelian randomization (MR) studies on frozen shoulder. Therefore, we conducted a two-sample MR study to explore whether socioeconomic status (years of schooling, average total household income before tax), obesity (body mass index and waist circumference), individual behaviors (smoking initiation, alcohol intake frequency, coffee intake, nonoily fish intake, tea intake, beef intake, bread intake, cheese intake, oily fish intake, and fresh fruit intake), and diabetes (type 1 and type 2 diabetes) are associated with frozen shoulder. The exposure datasets and the outcome dataset were extracted from the MRC Integrative Epidemiology Unit at the University of Bristol Open genome-wide association studies project (https://gwas.mrcieu.ac.uk/). We conducted MR analyses using the inverse variance weighted (primary method), MR-Egger, and weighted median methods and conducted heterogeneity and pleiotropy analyses. Type 1 diabetes (OR: 1.103; 95% CI: 1.053-1.156; P = .0000410) was associated with an increased risk of frozen shoulder. Cheese intake (OR: 0.490; 95% CI: 0.267-0.899; P = .0213), non-oily fish intake (OR: 0.0993; 95% CI: 0.0220-0.448; P = .00267), years of schooling (OR: 0.453; 95% CI: 0.349-0.588; P = .00000000277), and average total household income before tax (OR: 0.434; 95% CI: 0.253-0.743; P = .00236) were discovered as protective factors. No horizontal pleiotropy was found in all analyzes we performed (P > .05). Our study indicated that type 1 diabetes was a risk factor for frozen shoulder while cheese intake, non-oily fish intake, years of schooling, and average total household income before tax were considered as protective factors for frozen shoulder.

Circulating Biomarkers and Risk of Hypertension: A Two-Sample Mendelian Randomisation Study

OBJECTIVE

This study systematically assessed circulating proteins to identify new serum biomarkers and risk of hypertension using Mendelian randomisation.

METHODS

The associations between 4,782 human circulating proteins and the risk of hypertension were evaluated using two-sample Mendelian randomisation. The FinnGen study demonstrated a link between genetic predisposition and hypertension in 85,438 cases and 223,663 controls.

RESULTS

Inverse variance weighted and sensitivity analysis revealed nine proteins in circulation that have a causative effect on hypertension. SMOC1 and TIE1 were determined to be causative factors in the decreased likelihood of developing hypertension, with odds ratios of 0.86 (95% CI 0.81-0.91; p=1.06e-06) and 0.96 (95% CI 0.94-0.98; p=9.39e-05), respectively. NDUFB4, ETHE1, POFUT2, TRIL, ADAM23, GXYLT1, OXT, TPST2, and TMCC3 showed a possible connection to hypertension.

CONCLUSIONS

This two-sample Mendelian randomisation study found that SMOC1 and TIE1 are causally linked to hypertension, making them a promising target for therapy.

Mendelian randomization studies of depression: evidence, opportunities, and challenges

BACKGROUND

Major depressive disorder (MDD) poses a significant social and economic burden worldwide. Identifying exposures, risk factors, and biological mechanisms that are causally connected to MDD can help build a scientific basis for disease prevention and development of novel therapeutic approaches.

METHODS

In this systematic review, we assessed the evidence for causal relationships between putative causal risk factors and MDD from Mendelian randomization (MR) studies, following PRISMA. We assessed methodological quality based on key elements of the MR design: use of a full instrumental variable analysis and validation of the three key MR assumptions.

RESULTS

We included methodological details and results from 52 articles. A causal link between lifestyle, metabolic, inflammatory biomarkers, particular pathological states and MDD is supported by MR investigations, although results for each category varied substantially.

CONCLUSIONS

While this review shows how MR can offer useful information for examining prospective treatment targets and better understanding the pathophysiology of MDD, some methodological flaws in the existing literature limit reliability of results and probably underlie their heterogeneity. We highlight perspectives and recommendations for future works on MR in psychiatry.

Causal associations between female reproductive behaviors and psychiatric disorders: a lifecourse Mendelian randomization study

BACKGROUND

The timings of reproductive life events have been examined to be associated with various psychiatric disorders. However, studies have not considered the causal pathways from reproductive behaviors to different psychiatric disorders. This study aimed to investigate the nature of the relationships between five reproductive behaviors and twelve psychiatric disorders.

METHODS

Firstly, we calculated genetic correlations between reproductive factors and psychiatric disorders. Then two-sample Mendelian randomization (MR) was conducted to estimate the causal associations among five reproductive behaviors, and these reproductive behaviors on twelve psychiatric disorders, using genome-wide association study (GWAS) summary data from genetic consortia. Multivariable MR was then applied to evaluate the direct effect of reproductive behaviors on these psychiatric disorders whilst accounting for other reproductive factors at different life periods.

RESULTS

Univariable MR analyses provide evidence that age at menarche, age at first sexual intercourse and age at first birth have effects on one (depression), seven (anxiety disorder, ADHD, bipolar disorder, bipolar disorder II, depression, PTSD and schizophrenia) and three psychiatric disorders (ADHD, depression and PTSD) (based on p<7.14×10-4), respectively. However, after performing multivariable MR, only age at first sexual intercourse has direct effects on five psychiatric disorders (Depression, Attention deficit or hyperactivity disorder, Bipolar disorder, Posttraumatic stress disorder and schizophrenia) when accounting for other reproductive behaviors with significant effects in univariable analyses.

CONCLUSION

Our findings suggest that reproductive behaviors predominantly exert their detrimental effects on psychiatric disorders and age at first sexual intercourse has direct effects on psychiatric disorders.

Association of Urinary Incontinence and Depression: Findings From the National Health and Nutrition Examination Survey

OBJECTIVE

To evaluate the association between urinary incontinence and depression. An estimated 21 million adults in the United States (U.S.) reported at least one major depressive episode. Urinary incontinence has a well-described negative impact on quality of life.

METHODS

We included respondents aged ≥20 who participated in the 2017 - March 2020 National Health and Nutrition Examination Survey cycles. Our dichotomous outcomes were depression and clinical depression. The predictor variable urinary incontinence was assessed using the validated incontinence severity index. We fitted an adjusted multivariable logistic regression and performed interaction analysis for urinary incontinence and our variable of interest.

RESULTS

Among a weighted sample of 233.5 million people (unweighted 8256), 19.9 million (8.5%) reported depression (P < .001). The weighted population was 48.6% male, 55.2% married, and 63.4% non-Hispanic White (all P < .001). Moderate and severe urinary incontinence was associated with depression (adjusted odds ratio [aOR] 2.3; 95%CI [1.5-3.3]; aOR 3.8; 95%CI [2.5-3.3]; P < .001). No association was observed between urinary incontinence and clinical depression. Interaction analysis showed that men (aOR 3.62; 95%CI [2.13-6.15]; Pint<.001) and participants at the lowest socioeconomic status (aOR 2.2; 95%CI [1.3-3.71]; Pint=.005) with moderate/severe urinary incontinence had higher odds of depression than their continent counterparts.

CONCLUSION

We report that urinary incontinence is an independent predictor of depression in a nationally representative survey for men and those in the lowest socioeconomic tier. The association is most prominent among men and the socioeconomically disadvantaged population. This suggests that treatment for urinary incontinence may be important tool to reduce depression in the general population.

Ankylosing spondylitis and psychiatric disorders in European population: a Mendelian randomization study

Background

Epidemiologic evidence has demonstrated a correlation between ankylosing spondylitis and psychiatric disorders. However, little is known about the common genetics and causality of this association. This study aimed to investigate the common genetics and causality between ankylosing spondylitis (AS) and psychiatric disorders.

Methods

A two-sample Mendelian Randomization (MR) analysis was carried out to confirm causal relationships between ankylosing spondylitis and five mental health conditions including major depressive disorder (MDD), anxiety disorder (AXD), schizophrenia (SCZ), bipolar disorder (BIP), and anorexia nervosa (AN). Genetic instrumental variables associated with exposures and outcomes were derived from the largest available summary statistics of genome-wide association studies (GWAS). Bidirectional causal estimation of MR was primarily obtained using the inverse variance weighting (IVW) method. Other MR methods include MR-Egger regression, Weighted Median Estimator (WME), Weighted Mode, Simple Mode, and Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO). Sensitivity analyses are conducted to estimate the robustness of MR results.

Results

The findings suggest that AS may be causally responsible for the risk of developing SCZ (OR = 1.18, 95% confidence interval = (1.06, 1.31), P = 2.58 × 10-3) and AN (OR = 1.32, 95% confidence interval = (1.07, 1.64), P = 9.43 × 10-3). In addition, MDD, AXD, SCZ, AN, and BIP were not inversely causally related to AS (all p > 0.05).

Conclusion

Our study provides fresh insights into the relationship between AS and psychiatric disorders (SCZ and AN). Furthermore, it may provide new clues for risk management and preventive interventions for mental disorders in patients with AS.

Education is power: preserving cognition in the UK biobank

Introduction

Dementia is a debilitating syndrome characterized by the gradual loss of memory and cognitive function. Although there are currently limited, largely symptomatic treatments for the diseases that can lead to dementia, its onset may be prevented by identifying and modifying relevant life style risk factors. Commonly described modifiable risk factors include diet, physical inactivity, and educational attainment. Importantly, however, to maximize the utility of our understanding of these risk factors, tangible and meaningful changes to policy must also be addressed.

Objectives

Here, we aim to identify the mechanism(s) by which educational attainment influences cognition.

Methods

We investigated data from 502,357 individuals (Mage = 56.53, SDage = 8.09, 54.40% female) from the UK Biobank cohort via Structural Equation Modelling to illustrate links between predictor variables (i.e., Townsend Deprivation Index, coastal distance, greenspace, years of education), covariates (i.e., participant age) and cognitive function as outcome variables (i.e., pairs-matching, trail-making task B, fluid intelligence).

Results

Our model demonstrated that higher education was associated with better cognitive performance (ps < 0.001), and this relationship was mediated by indices of deprivation, and coastal distance.

Conclusion

Accordingly, our model evinces the mediating effect of socioeconomic and environmental factors on the relationship between years of education and cognitive function. These results further demonstrate the utility and necessity of adapting public policy to encourage equitable access to education and other supports in deprived areas.

Trends of mental health care utilization among US adults from 1999 to 2018

BACKGROUND

Mental health disorders affect millions of US adults, however, the trends and related factors for mental health care utilization in the US remain unknown.

AIMS

Our study aimed to assess the trend of mental health utilization and related socio-demographic factors in the US.

METHODS

The study included 55,052 individuals from the National Health and Nutrition Examination Survey (NHANES) in 1999-2018. Temporal trends in the percentages of mental health care utilizers were estimated across survey cycles. Trends and linked factors of mental health care utilization were assessed by a logistic regression model, while the non-linearity was estimated by restricted cubic splines.

RESULTS

From 1999 to 2018, the percentage of mental health care utilizers in the US adult population increased from 7.0 to 11.3% (P < 0.001); meanwhile, the trends in males and females were consistent. The percentage increased positively with age in individuals aged 20-39 (P < 0.001) or aged 60 and over (P = 0.003). The trends were consistent in three race/ethnicity groups (P < 0.05). The logistic regression analysis revealed that several disparities existed in the subpopulations. Older age, female, lower family poverty-income ratio (PIR), chronic diseases, higher educational level, and smoking were estimated to be associated with a higher percentage of mental health care.

CONCLUSIONS

The percentage of mental health care utilizers took on an increasing trend in the US adult population from 1999 to 2018. These trends were also observed in the subpopulations, but with disparities. Future research for exploring factors associated with mental health care utilizations is necessary.

Exploring the Relationship between Mood Disorders and Coexisting Health Conditions: The Focus on Nutraceuticals

Major depressive disorder and bipolar disorder are the leading causes of global disability. Approximately 50% of patients fail to attain remission, prompting a pronounced focus on the significance of dietary patterns and specific nutrients within the pathophysiology of mood disorders. The connection between chronic diseases and mood disorders follows a bidirectional pattern: physical ailments are interrelated with affective disorders, and, concurrently, mood symptoms often precede chronic diseases and have the potential to worsen their prognosis. Nutraceuticals affect factors that could potentially impact the onset of mood disorders: monoamines and brain-derived neurotrophic factor (BDNF) concentrations, neuroinflammation, oxidative stress, and sleep quality. Furthermore, mood disorders rarely manifest in isolation. Typically, such patients concurrently experience other mental disorders or somatic comorbidities: obesity, hypertension, diabetes, polycystic ovary syndrome (PCOS), etc., where providing nutritional support is also pertinent. To optimize the therapeutic approach for individuals with mood disorders, incorporating nutritional support may not solely ameliorate symptoms stemming directly from the mental condition, but also indirectly through interventions targeting comorbidities.

Identifying the mediating role of socioeconomic status on the relationship between schizophrenia and major depressive disorder: a Mendelian randomisation analysis

Depressive disorder prevalence in patients with schizophrenia has been reported to be 40%. People with low socioeconomic status (SES) are more likely to suffer from schizophrenia and major depressive disorder (MDD). However, the causal relationship between schizophrenia and depression and the potential mediating role of SES remains unclear. Two-sample Mendelian randomization (MR) analyses were conducted to explore the bidirectional causal relationship between schizophrenia and MDD with the largest sample size of European ancestry from public genome-wide association studies (sample size ranged from 130,644 to 480,359). Inverse variance weighted (IVW) method was used as the primary analysis, and several canonical MR methods were used as validation analyses. The mediating role of SES (educational years, household income, employment status, and Townsend deprivation index) was estimated by the two-step MR method. MR analyses showed that genetically predicted schizophrenia was associated with an increased risk of MDD (IVW odds ratio [OR] = 1.137 [95% CI 1.095, 1.181]). Reversely, MDD was also associated with an increased risk of schizophrenia (IVW OR = 1.323 [95% CI 1.118, 1.565]). The mediation analysis via the two-step MR method revealed that the causal effect of schizophrenia on MDD was partly mediated by the Townsend deprivation index with a proportion of 10.27%, but no significant mediation effect was found of SES on the causal effect of MDD on schizophrenia. These results suggest a robust bidirectional causal effect between schizophrenia and MDD. Patients with schizophrenia could benefit from the early and effective intervention of the Townsend deprivation index.

Modifiable risk factors of major depressive disorder: A Mendelian randomization study

Identifying modifiable risk factors early on is essential to prevent major depressive disorder (MDD). This study systematically investigated the causal relationship between 19 modifiable risk factors and MDD. Single-nucleotide polymorphisms (SNPs) associated with 19 potentially modifiable risk factors were screened via the genome-wide association study (GWAS) enrolling individuals of European descent. Summary-level data for MDD (59,851 cases and 113,154 controls) were extracted from the UK Biobank. The inverse-variance-weighted (IVW) method was utilized as the primary analysis. Sensitivity analyses were performed using the MR-Egger method, the Maximum likelihood method, the MR-pleiotropy residual sum outlier (MR-PRESSO) method, and MR-robust adjusted profile score (MR-RAPS) method. MR-Egger regression, heterogeneity tests, pleiotropy tests, and leave-one-out tests were also performed to analyze sensitivity. The MR Steiger test was used to verify the directionality of the exposure to the outcome. Genetically predicted smoking initiation increased the risk of MDD (P = 6.00E-09), while smoking status: never and past tobacco smoking decreased the risk of MDD (all P < 0.01). In addition, education level was inversely associated with MDD risk (all P < 0.01). Genetically instrumented sleeplessness/insomnia, daytime naps, and nap during the day were positively related to the risk of MDD (all P < 0.01). Personal feelings, including guilt, hurt, tension, and worry too long after an embarrassing experience, had a suggestive increased risk for MDD (all P < 0.000). The remaining five modifiable risk factors were all causally associated with the risk of MDD, including neuroticism, neuroticism scores, body mass index (BMI), average total household income before tax, and types of physical activity in the last 4 weeks (all P < 0.01). All 19 potentially modifiable risk factors were causally associated with the risk of MDD. The main hypothesis of this MR study was that identifying and intervening in these 19 potentially modifiable risk factors could be beneficial to the prevention and treatment of MDD and further reduce mortality and economic burden.

Causal association between basal metabolic rate and risk of cardiovascular diseases: a univariable and multivariable Mendelian randomization study

Basal metabolic rate (BMR) is associated with cardiovascular health; however, the causal relationship between BMR and the risk of cardiovascular diseases (CVDs) remains unclear. This study aimed to investigate the potential causal relationship of BMR on common CVDs including aortic aneurysm (AA), atrial fibrillation and flutter (AFF), calcific aortic valvular stenosis (CAVS), heart failure (HF), and myocardial infarction (MI) by Mendelian randomization (MR). The univariable MR analysis using inverse variance weighted (IVW) model as the primary analysis method revealed that genetically predicted higher BMR causally increased the risk of AA [IVW odds ratio (OR) = 1.34, 95% confidence interval CI  1.09-1.65, p = 0.00527], AFF (IVW OR = 1.87, 95% CI  1.65-2.12, p = 1.697 × E-22), and HF (IVW OR = 1.35, 95% CI  1.20-1.51, p = 2.364 × E-07), while causally decreasing the risk of MI (IVW OR = 0.83, 95% CI  0.73-0.93, p = 0.00255). In the multivariable MR analysis, which controlled for common cardiovascular risk factors, direct effects of BMR on an increased risk of AA and AFF, as well as a decreased risk of MI, but an attenuated causal effect on HF, were observed. In conclusion, the current MR study provides evidence for a causal relationship between BMR and the risk of AA, AFF, HF, and MI.

Causal links between socioeconomic status, leisure sedentary behaviours and gastro-oesophageal reflux disease: a multivariable two-sample Mendelian randomisation study

INTRODUCTION

We implemented a two-sample multivariable Mendelian randomisation (MR) analyses to estimate the causal effect of socioeconomic status and leisure sedentary behaviours on gastro-oesophageal reflux disease (GERD).

METHODS

Independent single-nucleotide polymorphisms associated with socioeconomic status and leisure sedentary behaviours at the genome-wide significance level from the Medical Research Council Integrative Epidemiology Unit (MRC-IEU) UK Biobank were selected as instrumental variables. Summary-level data for GERD were obtained from a recent publicly available genome-wide association involving 78 707 GERD cases and 288 734 controls of European descent. Univariable and multivariable two-sample MR analyses, using inverse variance weighted method for primary analyses, were performed to jointly evaluate the effect of socioeconomic status and leisure sedentary behaviours on GERD risk.

RESULTS

Three socioeconomic status, including educational attainment (OR 0.46; 95% CI 0.30 to 0.69; p<0.001), average total household income before tax (OR 0.65; 95% CI 0.47 to 0.90; p=0.009) and Townsend Deprivation Index at recruitment (OR 1.60; 95% CI 1.06 to 2.41; p=0.026), were independently and predominately responsible for the genetic causal effect on GERD. In addition, one leisure sedentary behaviour, such as time spent watching television, was independently and predominately responsible for genetic causal effect on GERD (OR 3.74; 95% CI 2.89 to 4.84; p<0.001). No causal effects of social activities and driving on GERD were observed.

CONCLUSIONS

Genetically predicted Townsend Deprivation Index at recruitment and leisure watching television were causally associated with increased risk of GERD, and age at completion of full-time education and average total household income before tax were causally associated with decreased risk of GERD.

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

BACKGROUND

Evidence suggested strong associations between women's reproductive factors and major depressive disorder (MDD), but their causalities are unclear.

METHODS

Using female-specific SNPs as genetic instruments obtained from large-scale genome-wide association studies for women's reproductive traits, we designed two-sample univariable and multivariable Mendelian randomization (MR) analysis to evaluate the causal effects of women's reproductive traits on MDD. For both univariable MR (UVMR) and multivariable MR (MVMR), the inverse variance weighting estimates were reported as main results. MR-Egger, weighted median, and generalized summary-data-based MR (GSMR) methods for UVMR, and MVMR-Egger and MVMR-robust methods for MVMR were used as sensitivity analyses. Negative control analyses, MVMR of age at first birth (AFB) and age at first sexual intercourse (AFS) on MDD, and sex-combined genetic variants for AFB and AFS were performed to enhance the robustness of our study.

RESULTS

There was substantial evidence for associations of genetically predicted later age at menarche (AAM) (odds ratio (OR) = 0.97, 95 % confidence interval (CI) = 0.94-0.99, P = 0.007), AFB (OR = 0.91, 95 % CI = 0.86-0.97, P = 0.002) and AFS (OR = 0.70, 95 % CI = 0.60-0.80, P < 0.001) with lower MDD risk in UVMR. After adjustment of BMI and educational attainment using MVMR, we found consistently significant causal effects of AAM (OR = 0.95, 95 % CI = 0.92-0.99, P = 0.006), AFB (OR = 0.88, 95 % CI = 0.84-0.91, P < 0.001) and AFS (OR = 0.71, 95 % CI = 0.64-0.79, P < 0.001) on MDD.

CONCLUSIONS

Our results provide compelling evidence that early AAM, AFB, and AFS are risk factors for MDD. Promoting the cognition of reproductive health care for women may reduce the risk of MDD.