Evidence for causal effects of lifetime smoking on risk for depression and schizophrenia: a Mendelian randomisation study

Causal association and shared genetics between telomere length and COVID-19 outcomes: New evidence from the latest large-scale summary statistics

Background

Observational studies suggested that leukocyte telomere length (LTL) is shortened in COVID-19 patients. However, the genetic association and causality remained unknown.

Methods

Based on the genome-wide association of LTL (N = 472,174) and COVID-19 phenotypes (N = 1086,211-2597,856), LDSC and SUPERGNOVA were used to estimate the genetic correlation. Cross-trait GWAS meta-analysis, colocalization, fine-mapping analysis, and transcriptome-wide association study were conducted to explore the shared genetic etiology. Mendelian randomization (MR) was utilized to infer the causality. Upstream and downstream two-step MR was performed to investigate the potential mediating effects.

Results

LDSC identified a significant genetic association between LTL and all COVID-19 phenotypes (rG < 0, p < 0.05). Six significant regions were observed for LTL and COVID-19 susceptibility and hospitalization, respectively. Colocalization analysis found rs144204502, rs34517439, and rs56255908 were shared causal variants between LTL and COVID-19 phenotypes. Numerous biological pathways associated with LTL and COVID-19 outcomes were identified, mainly involved in -immune-related pathways. MR showed that longer LTL was significantly associated with a lower risk of COVID-19 severity (OR [95% CI] = 0.81 [0.71-0.92], p = 1.24 ×10-3) and suggestively associated with lower risks of COVID-19 susceptibility (OR [95% CI] = 0.96 [0.92-1.00], p = 3.44 ×10-2) and COVID-19 hospitalization (OR [95% CI] = 0.89 [0.80-0.98], p = 1.89 ×10-2). LTL partially mediated the effects of BMI, smoking, and education on COVID-19 outcomes. Furthermore, six proteins partially mediated the causality of LTL on COVID-19 outcomes, including BNDF, QPCT, FAS, MPO, SFTPB, and APOF.

Conclusions

Our findings suggested that shorter LTL was genetically associated with a higher risk of COVID-19 phenotypes, with shared genetic etiology and potential causality.

Alcohol Use Disorder-Associated DNA Methylation in the Nucleus Accumbens and Dorsolateral Prefrontal Cortex

Background

Alcohol use disorder (AUD) has a profound public health impact. However, understanding of the molecular mechanisms that underlie the development and progression of AUD remains limited. Here, we investigated AUD-associated DNA methylation changes within and across 2 addiction-relevant brain regions, the nucleus accumbens and dorsolateral prefrontal cortex.

Methods

Illumina HumanMethylation EPIC array data from 119 decedents (61 cases, 58 controls) were analyzed using robust linear regression with adjustment for technical and biological variables. Associations were characterized using integrative analyses of public annotation data and published genetic and epigenetic studies. We also tested for brain region-shared and brain region-specific associations using mixed-effects modeling and assessed implications of these results using public gene expression data from human brain.

Results

At a false discovery rate of ≤.05, we identified 105 unique AUD-associated CpGs (annotated to 120 genes) within and across brain regions. AUD-associated CpGs were enriched in histone marks that tag active promoters, and our strongest signals were specific to a single brain region. Some concordance was found between our results and those of earlier published alcohol use or dependence methylation studies. Of the 120 genes, 23 overlapped with previous genetic associations for substance use behaviors, some of which also overlapped with previous addiction-related methylation studies.

Conclusions

Our findings identify AUD-associated methylation signals and provide evidence of overlap with previous genetic and methylation studies. These signals may constitute predisposing genetic differences or robust methylation changes associated with AUD, although more work is needed to further disentangle the mechanisms that underlie these associations and their implications for AUD.

Inflammatory cytokines and carpal tunnel syndrome: A causal relationship revealed

OBJECTIVES

Carpal tunnel syndrome (CTS) and certain inflammatory cytokines have been linked in observational studies; however, the exact causative linkages remain unknown. The purpose of this study is to investigate any possible link between the onset of CTS and 91 inflammatory cytokines.

METHODS

A two-sample bidirectional Mendelian randomization (MR) approach was used in this investigation. 91 circulating inflammatory cytokines' genetic variants were retrieved from the European ancestry genome-wide association study (GWAS) database. From germline GWAS, summary data for 24,766 CTS patients and 360,538 controls were gathered. The instrumental variables were single nucleotide polymorphisms (SNPs) that were highly correlated with the 91 inflammatory cytokines. The random-effects inverse-variance weighted (IVW) approach was employed in the primary analysis, and multiple comparisons were subjected to the Bonferroni correction. Sensitivity analysis was performed to evaluate the validity of the causal relationship.

RESULTS

Our findings showed a negative correlation between CCL19, FGF-19, IL-5, TGF-alpha, TRAIL, and the risk of CTS. Specifically, CCL19 (odds ratio [OR]: 0.944, 95 % confidence interval [CI]: 0.894-0.996, p = 0.0349), FGF-19 (OR: 0.940, 95 % CI: 0.894-0.987, p = 0.0133), IL-5 (OR: 0.936, 95 % CI: 0.885-0.990, p = 0.0212), TGF-alpha (OR: 0.902, 95 % CI: 0.838-0.970, p = 0.0057), and TRAIL (OR: 0.926, 95 % CI: 0.881-0.974, p = 0.0026) were inversely related to CTS risk. Conversely, CCL20, IL-2RB, and IL-6 were positively associated with an increased risk of CTS. Specifically, CCL20 (OR: 1.072, 95 % CI: 1.005-1.142, p = 0.0334), IL-2RB (OR: 1.067, 95 % CI: 1.001-1.137, p = 0.0463), and IL-6 (OR: 1.088, 95 % CI: 1.005-1.177, p = 0.0365) were positively correlated with CTS risk. Reverse Mendelian randomization analyses indicated no evidence of a reverse causal relationship between CTS and inflammatory cytokines.

CONCLUSION

According to this study, there is a causal link between CTS and certain inflammatory cytokines, which suggests that these cytokines may be important in the pathophysiology of CTS. To confirm these results and investigate the specific function of these cytokines in the beginning and development of CTS, more investigation is necessary.

History of tobacco smoking and alcohol use can predict the effectiveness of electroconvulsive therapy in individuals with schizophrenia: A multicenter clinical trial

BACKGROUND

Current research has found that factors such as gender, age, and family history can predict the efficacy of electroconvulsive therapy (ECT) in individuals with schizophrenia. In our clinical practice, we anecdotally observed that tobacco smokers and alcohol drinkers with schizophrenia seemed to respond more effectively to ECT than non-smokers and non-drinkers. The current study aimed to examine whether history of tobacco smoking or alcohol consumption serve as indicators for predicting therapeutic efficacy of ECT in individuals with schizophrenia.

METHODS

A total of 481 individuals receiving ECT combined with antipsychotic medication (ECT + AP medication) completed a two-week (six sessions of ECT) follow-up; 106 individuals receiving only antipsychotic medication (AP medication) also completed a two-week follow-up. Smoking, alcohol consumption, and AP medication usage was recorded for these individuals. Severity of psychotic symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

ECT + AP medication: Compared to schizophrenic individuals without a history of smoking (non-smokers), those with a history of smoking (smokers) showed a high decrease in negative symptoms (36.96% vs 24.76%; F = 5.974, p = 0.015). While, compared to individuals without a history of alcohol consumption (non-drinkers), those with a history of alcohol consumption (drinkers) showed a high decrease in positive symptoms (48.90% vs 41.47%; F = 5.074, p = 0.025). AP medication: No differences were found in symptom reduction between smokers and non-smokers or between drinkers and non-drinkers (p > 0.05).

CONCLUSIONS

Smoking history in schizophrenic individuals independently predicts better improvement in negative symptoms after ECT, while alcohol consumption history independently predicts better improvement in positive symptoms after ECT. This is a clinically significant finding.

The causality between smoking and intervertebral disc degeneration mediated by IL-1β secreted by macrophage: A Mendelian randomization study

There is still a lack of high-level evidence regarding the causal relationship between smoking and intervertebral disc degenerative diseases. This study utilized data from genome wide analysis studies and conducted two-sample Mendelian randomization analyses across multiple heterogeneous datasets. We evaluated the causal relationships between smoking behavior, serum inflammatory factors, serum chemokines, and intervertebral disc degeneration. Sensitivity analysis was performed to examine data heterogeneity and the pleiotropy of causal effects. The results indicated that smokers were liable to develop intervertebral disc degeneration (OR 1.770; 95 % CI, 1.519-2.064; p = 2.992 × 10-13), and long-term smoking behavior increased the risk of intervertebral disc degeneration (OR 1.715; 95 % CI 1.475-1.994; P = 2.220 × 10-12). Additionally, a causal relationship was confirmed between serum IL-1β level and intervertebral disc degeneration (OR 1.087; 95 % CI, 1.023-1.154; p = 0.007). The "smoking index" representing lifelong smoking habit was also found to be causally related to serum MCP-3 level(β = 0.292; SE = 0.093; p = 0.002). All of the causality mentioned above remained stable in sensitivity tests. Based on the analysis results and fundamental medicine theories around macrophage-induced inflammation in degenerative intervertebral discs, we have constructed a new mechanism that long-term smoking could induce an increase in serum MCP-3 level, promoting the gathering and activation of monocyte macrophages. Furthermore, the recruited macrophages led to an increase in local IL-1β within the intervertebral disc, ultimately exacerbating the process of intervertebral disc degeneration. What we have found is expected to accelerate the development of prevention and treatment of intervertebral disc degeneration.

Exploring the effect of lifestyle behaviors and socioeconomic status on atrial fibrillation: the mediating role of 91 inflammatory cytokines

Background

Atrial fibrillation (AF) is one of the most prevalent cardiac arrhythmias and has a significant economic and social burden. Whether it is associated with lifestyle behaviors and socioeconomic status is currently poorly understood. This study aimed to explore the relationship among these factors and determine the role of inflammatory cytokines.

Method

We investigated the causal effects of lifestyle behaviors and socioeconomic status on AF using bidirectional two-sample Mendelian randomization (MR). Instrumental variables were obtained from a publicly available genome-wide association study. A two-step MR was conducted to determine the mediating role of 91 inflammatory cytokines. Inverse variance weighted was used as the main method with four supplementary MR methods. To obtain more robust results, several sensitivity analyses were conducted.

Result

The results indicated that seven of the lifestyle behaviors [smoking initiation, vegetable intake, coffee consumption (cups/day), dozing, lifetime smoking index, napping, and alcohol abuse] were potential risk factors for AF. One socioeconomic status, education attainment (years of education), was causally associated with a decreased risk of AF. Moreover, we found that thymic stromal lymphopoietin, CD40l receptor, C-X-C motif chemokine 6, and C-X-C motif chemokine 11 levels mediated the causal effect, at proportions of 13.6%, 4.1%, 4.3%, and 6.9%, respectively.

Conclusion

Our findings provide insight into the relationship between lifestyle behaviors, socioeconomic status, and AF. Inflammatory cytokines are potential mediators of this relationship.

Association of Genetically Predicted Anxiety and Depression With Functional Outcome After Ischemic Stroke: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVES

Anxiety and depression have implications for ischemic stroke recovery. This study explored the association of genetically predicted anxiety and depression with functional outcome after ischemic stroke using Mendelian randomization (MR) approach.

METHODS

Independent genetic variants associated with anxiety and depression at genome-wide significance level (p < 5 × 10-8) were obtained from large-scale genome-wide association studies (Nmax = 1,306,354). Genetic results of poststroke outcome were obtained from Genetics of Ischemic Stroke Functional Outcome meta-analysis (N = 6,021). Three months after ischemic stroke event, the functional outcome was appraised with the modified Rankin Scale (mRS) score, and a mRS >2 was defined as worse functional outcome. Odds ratios (ORs) and 95% CIs are reported for the association of genetically predicted anxiety and depression with functional outcome after ischemic stroke. The inverse-variance weighted method was adopted to pool estimates. Alternative MR methods such as the weighted median and MR using the Robust Adjusted Profile Score were used as sensitivity analyses. The intercept of MR-Egger regression was also adopted to assess pleiotropy. The heterogeneity among variants was assessed by I2 and Q statistics.

RESULTS

Genetic liability to depression was associated with worse functional outcome after stroke (mRS 3-6, OR 2.30; 95% CI 1.18-4.49, p = 0.015). Sensitivity analyses produced consistent results. The bidirectional MR analysis indicates that poststroke outcome did not influence liability to depression (OR 1.01, 95% CI 0.99-1.03; p = 0.436). By comparison, genetic liability to anxiety was not related with poststroke outcome (OR 1.03; 95% CI 0.71-1.50; p = 0.869). Analyses in models without adjustment for stroke severity also indicated that genetic liability to depression was related with poor functional outcome after ischemic stroke (OR 2.54; 95% CI 1.41-4.58; p = 0.002). No evidence of heterogeneity or directional pleiotropy was observed (p > 0.05).

DISCUSSION

Our MR study provides evidence to support detrimental effects of depression on ischemic stroke functional outcome. Future studies are warranted to explore whether clinical intervention on depression can ameliorate functional outcome after ischemic stroke.

Smoking and alcohol by HPV status in head and neck cancer: a Mendelian randomization study

HPV-positive and HPV-negative head and neck squamous cell carcinoma (HNSCC) are recognized as distinct entities. There remains uncertainty surrounding the causal effects of smoking and alcohol on the development of these two cancer types. Here we perform multivariable Mendelian randomization (MR) to evaluate the causal effects of smoking and alcohol on the risk of HPV-positive and HPV-negative HNSCC in 3431 cases and 3469 controls. Lifetime smoking exposure, as measured by the Comprehensive Smoking Index (CSI), is associated with increased risk of both HPV-negative HNSCC (OR = 3.03, 95%CI:1.75-5.24, P = 7.00E-05) and HPV-positive HNSCC (OR = 2.73, 95%CI:1.39-5.36, P = 0.003). Drinks Per Week is also linked with increased risk of both HPV-negative HNSCC (OR = 7.72, 95%CI:3.63-16.4, P = 1.00E-07) and HPV-positive HNSCC (OR = 2.66, 95%CI:1.06-6.68, P = 0.038). Smoking and alcohol independently increase the risk of both HPV-positive and HPV-negative HNSCC. These findings have important implications for understanding the modifying risk factors between HNSCC subtypes.

Major Psychiatric Disorders, Substance Use Behaviors, and Longevity

Importance

Observational studies suggest that major psychiatric disorders and substance use behaviors reduce longevity, making it difficult to disentangle their relationships with aging-related outcomes.

Objective

To evaluate the associations between the genetic liabilities for major psychiatric disorders, substance use behaviors (smoking and alcohol consumption), and longevity.

Design, Settings, and Participants

This 2-sample mendelian randomization (MR) study assessed associations between psychiatric disorders, substance use behaviors, and longevity using single-variable and multivariable models. Multiomics analyses were performed elucidating transcriptomic underpinnings of the MR associations and identifying potential proteomic therapeutic targets. This study sourced summary-level genome-wide association study (GWAS) data, gene expression, and proteomic data from cohorts of European ancestry. Analyses were performed from May 2022 to November 2023.

Exposures

Genetic susceptibility for major depression (n = 500 199), bipolar disorder (n = 413 466), schizophrenia (n = 127 906), problematic alcohol use (n = 435 563), weekly alcohol consumption (n = 666 978), and lifetime smoking index (n = 462 690).

Main Outcomes and Measures

The main outcome encompassed aspects of health span, lifespan, and exceptional longevity. Additional outcomes were epigenetic age acceleration (EAA) clocks.

Results

Findings from multivariable MR models simultaneously assessing psychiatric disorders and substance use behaviorsm suggest a negative association between smoking and longevity in cohorts of European ancestry (n = 709 709; 431 503 [60.8%] female; β, -0.33; 95% CI, -0.38 to -0.28; P = 4.59 × 10-34) and with increased EAA (n = 34 449; 18 017 [52.3%] female; eg, PhenoAge: β, 1.76; 95% CI, 0.72 to 2.79; P = 8.83 × 10-4). Transcriptomic imputation and colocalization identified 249 genes associated with smoking, including 36 novel genes not captured by the original smoking GWAS. Enriched pathways included chromatin remodeling and telomere assembly and maintenance. The transcriptome-wide signature of smoking was inversely associated with longevity, and estimates of individual smoking-associated genes, eg, XRCC3 and PRMT6, aligned with the smoking-longevity MR analyses, suggesting underlying transcriptomic mediators. Cis-instrument MR prioritized brain proteins associated with smoking behavior, including LY6H (β, 0.02; 95% CI, 0.01 to 0.03; P = 2.37 × 10-6) and RIT2 (β, 0.02; 95% CI, 0.01 to 0.03; P = 1.05 × 10-5), which had favorable adverse-effect profiles across 367 traits evaluated in phenome-wide MR.

Conclusions

The findings suggest that the genetic liability of smoking, but not of psychiatric disorders, is associated with longevity. Transcriptomic associations offer insights into smoking-related pathways, and identified proteomic targets may inform therapeutic development for smoking cessation strategies.

Correlations among nicotine dependence, health-related quality of life, and depression in current smokers: a cross-sectional study with a mediation model

Background

Although the negative impact of smoking and health-related quality of life (HRQoL) on depression has been confirmed in various studies, There has been little exploration of how HRQoL mediates the relationship between smoking and depression. The purpose of the current study was to examine the relationship between smoking and depression in the Chinese current smokers with nicotine dependence and the mediating role of HRQoL.

Methods

A cross-sectional study named "Psychology and Behavior Investigation of Chinese Residents" was conducted from July 10 to September 15, 2021 in China. Nicotine dependence, HRQoL and depression were measured by Fagerstrom Test for Nicotine Dependence (FTND), the European Five Dimensional Five Level Health scale (EQ-5D-5L) and the 9-item Patient Health Questionnaire (PHQ-9) respectively. Information on age, gender, place of residence, household registration, education level, marital status, employment status, average family monthly income, drinking frequency, living status, BMI, multiple chronic conditions were also collected. Pearson's correlation test and logistic regression analysis were conducted to explore the association between nicotine dependence, HRQoL and depression and a mediation analysis was applied to explore the mediating effect of the HRQoL on this relationship.

Results

A total of 1,381 current smokers were included in the study. The participants showed a moderate level of nicotine dependence with a mean of 1.36(SD=1.50), a relatively high level of HRQoL scores (Mean=0.94, SD=0.13), and a depression score with a mean of 6.48(SD=6.09). Approximately 22.74% (314/1,381) of the participants were considered to indicate depression. In the univariable regression model, it was found that nicotine dependence was positively associated with depression (OR:1.094, 95%CI: 1.008-1.187), while HRQoL was negatively associated with depression (OR:0.011, 95%CI: 0.004-0.033). In the multivariable regression model, HRQoL was still notably associated with depression (OR:0.008, 95%CI: 0.002-0.027), however, the positive association was not observed between nicotine dependence and depression. The Pearson's correlation test demonstrated that nicotine dependence was negatively correlated with HRQoL(rs= -0.147, P<0.001) and HRQoL was negatively correlated with depression(rs= -0.275, P<0.001). In contrast, nicotine dependence was positively correlated with depression(rs= 0.136, P<0.001). Mediation analysis found that HRQoL moderated the relationship between nicotine dependence and depression with a mediating effect of 26.49%.

Conclusions

The findings support that nicotine dependence is positively associated with depression and HRQoL is negatively associated with depression in current smokers. HRQoL mediated the relationship between nicotine dependence and depression. The well-established imperative interventions aimed at promoting smoking cessation and improving quality of life may benefit for alleviation of depression in current smokers.

Smoking behaviors, physical activities, pulmonary diseases and COVID-19 severity: A Mendelian randomization study

Smoking behaviors, physical activities, and pulmonary diseases have been revealed to be associated with COVID-19 severity through observational research. The possible causative effect remains undetermined. To investigate this, we thus carried out a Mendelian randomization (MR) analysis. We chose genetic variants from genome-wide association studies that are strongly linked to 5 exposures related to smoking, 1 exposure related to drinking, 3 levels of physical activity, and 3 pulmonary diseases. The COVID-19 Host Genetics Initiative provided summary-level data for severe COVID-19 (13,769 cases and 1,072,442 noncases), hospitalized COVID-19 (32,519 cases and 2,062,805 noncases), and COVID-19 susceptibility (122,616 cases and 2,475,240 noncases). Univariate and multivariate MR analyses were carried out. Significant associations were found between severe COVID-19 and cigarette smoking per day (OR = 1.357, 95% CI: 1.087-1.694), lifetime smoking index (OR = 2.277, 95% CI: 1.602-3.325), and interstitial lung disease (OR = 1.23, 95% CI: 1.112-1.362), hospitalized COVID-19 and lifetime smoking index (OR = 2.199, 95% CI: 1.738-2.781), smoking initiation (OR = 1.419, 95% CI: 1.230-1.637), and interstitial lung disease (OR = 1.146, 95% CI: 1.082-1.214), as well as COVID-19 susceptibility and lifetime smoking index (OR = 1.39, 95% CI: 1.252-1.543), smoking initiation (OR = 1.235, 95% CI: 1.163-1.311), and duration of vigorous activity per day (OR = 0.733, 95% CI: 0.574-0.935). Duration of vigorous activity per day was suggestively inversely linked to hospitalized COVID-19 (OR = 0.434, 95% CI: 0.221-0.853) and severe COVID-19 (OR = 0.323, 95% CI: 0.123-0.850). The association for lifetime smoking index remained consistent with severe COVID-19, hospitalized COVID-19, and COVID-19 susceptibility in multivariable MR analysis. Genetic liability to lifetime smoking index mediated the interstitial lung disease effects on severe COVID-19 risk (21.0%) and hospitalized COVID-19 risk (14.4%). This study identified several smoking behaviors, duration of vigorous activity per day, and interstitial lung disease that may be causally related to COVID-19 severity.

Exploring genetic associations in systemic lupus erythematosus through Mendelian randomization: implications for novel biomarkers and therapeutic targets

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a significant health burden. There is an essential need for novel biomarkers and therapeutic targets to improve diagnosis and management. Mendelian randomization (MR) was applied to explore causal links between SLE and various biomarkers like immune cells, metabolites, and inflammatory cytokines using multiple databases. Initially, biomarkers significantly associated with SLE were identified. Bidirectional MR helped clarify these relationships, and a two-step mediation MR examined their effects on SLE risk. Intersection analysis was used to identify biomarkers with consistent effects across datasets. Four biomarkers were identified as having significant associations with SLE risk: 1-palmitoyl-2-arachidonoyl-GPI levels [odds ratio (OR), 1.379; 95% confidence interval (CI), 1.180 to 1.613; FDR, 0.046], IL-17A levels (OR, 2.197; 95% CI, 1.412 to 3.418; FDR, 0.044), N-acetyl-aspartyl-glutamate (NAAG) levels (OR, 0.882; 95% CI, 0.831 to 0.936; FDR, 0.030), and ribitol levels (OR, 0.743; 95% CI, 0.644 to 0.857; FDR, 0.012). Bidirectional MR showed an inverse effect of NAAG on IL-17A levels (OR, 0.978; 95% CI, 0.962 to 0.994; p = 0.006). Mediation analysis indicated that NAAG influenced SLE risk both directly (beta =  - 0.108) and indirectly through IL-17A (beta =  - 0.018), highlighting the potential mediating role of IL-17A. After expanding the significance criteria to p < 0.05, intersection analysis across multiple datasets revealed 29 biomarkers with consistent beta directions, including 19 potential risk factors (beta > 0) and 10 protective factors (beta < 0) for SLE. This research has revealed significant genetic associations with SLE and demonstrated that IL-17A mediates the relationship between NAAG levels and SLE risk, highlighting potential new targets for personalized therapeutic interventions. Key Points • This study employs MR to identify significant genetic associations between various biomarkers and SLE, providing novel insights into potential biomarkers and therapeutic targets. • Four key biomarkers were identified as significantly associated with SLE risk: 1-palmitoyl-2-arachidonoyl-GPI, IL-17A, N-acetyl-aspartyl-glutamate (NAAG), and ribitol. • The findings suggest that NAAG levels have a protective effect against SLE, partly mediated through IL-17A, indicating a complex interplay between these biomarkers in the pathogenesis of SLE. • Intersectional analysis across multiple datasets revealed 29 biomarkers with consistent effects on SLE risk, highlighting new directions for future research and potential personalized therapeutic strategies.

Circulating micronutrient levels and respiratory infection susceptibility and severity: a bidirectional Mendelian randomization analysis

Background

Limited and inconclusive data from observational studies and randomized controlled trials exist on the levels of circulating micronutrients in the blood and their association with respiratory infections.

Methods

A Mendelian randomization (MR) analysis was conducted to assess the impact of 12 micronutrients on the risk of three types of infections [upper respiratory tract infections (URTI), lower respiratory tract infections (LRTI), and pneumonia] and their 14 subtypes. This study utilized a bidirectional MR approach to evaluate causal relationships and included a range of sensitivity analyses and multivariable MR to address potential heterogeneity and pleiotropy. The threshold for statistical significance was set at p < 1.39 × 10-3.

Results

Meta-analysis revealed that higher levels of circulating copper were significantly associated with a reduced risk of URTI (odds ratio (OR) = 0.926, 95% CI: 0.890 to 0.964, p = 0.000195). Additionally, copper demonstrated a suggestive association with a reduced risk of LRTI (p = 0.0196), and Vitamin B6 was nominally associated with a reduced risk of pneumonia (p = 0.048). Subtype analyses further indicated several suggestive associations: copper reduces the risk of acute pharyngitis (p = 0.029), vitamin C increases the risk of critical care admissions for pneumonia (p = 0.032) and LRTI (p = 0.021), and folate reduces the risk of viral pneumonia (p = 0.042). No significant connections were observed for other micronutrients.

Conclusion

We observed a genetically predicted potential protective effect of copper in susceptibility to upper respiratory infections. This provides new insights for further research into the role of micronutrients in the prevention and treatment of infection.

Smoking as a mediator in the association between major depressive disorder and schizophrenia on lung cancer risk: a bidirectional/multivariable and mediation Mendelian randomization study

Background & Aims

Major depressive disorder and schizophrenia have been hypothesized to be closely associated with cancer. However, the associations between these psychiatric conditions and the development of lung cancer remain uncertain. This study aimed to explore the causal relationship among major depressive disorder, schizophrenia, and the risk of lung cancer.

Methods

Two-sample bidirectional/multivariable and mediation Mendelian randomization (MR) analyses were conducted. Genome-wide summary data on major depressive disorder (N=500,199) and schizophrenia (N=127,906) were utilized. Data on the risk of lung cancer (overall, adenocarcinoma, and squamous cell) were collected from a cohort of individuals of European ancestry (N=27,209). Three smoking-related behaviors (smoking initiation, pack years of smoking, and cigarettes smoked per day) were included in the multivariable and mediation MR analyses.

Results

Patients with schizophrenia had a significantly greater risk of developing lung cancer (odds ratio (OR) = 1.144, 95% confidence interval (95% CI): 1.048-1.248, P = 0.003). The number of cigarettes smoked per day partially mediated the relationship between schizophrenia and the overall risk of lung cancer (OR = 1.185, 95% CI: 1.112-1.264, P = 0.021, proportion of mediation effect: 61.033%). However, there is no reliable evidence indicating an association between major depressive disorder and the risk of lung cancer (overall, adenocarcinoma, and squamous cell cancer).

Conclusions

The findings indicated an association between schizophrenia and an increased risk of lung cancer, with smoking served as a partial mediator. When smoking was included in the regression analysis, the explanatory power of schizophrenia diagnosis was reduced, suggesting that smoking may be an important causal contributor to lung cancer in this population. Given the high prevalence of smoking among individuals with schizophrenia, these results underscore the need for further research to explore the underlying mechanisms of smoking's impact. Consequently, greater emphasis should be placed on monitoring the respiratory health of individuals with schizophrenia and implementing early interventions to address smoking-related behaviors.

Short-Term Blood Pressure Variability among Young Adults at High or Low Risk for Depression

Background: Depression has been shown to have adverse effects on blood pressure (BP) and is associated with high blood pressure variability (BPV). In turn, high short-term BPV has been related to eventual cardiovascular risk. But it is not clear how early in adulthood the detrimental effects of depression on BPV may be discerned, if being at high risk for depression also compromises BPV, and whether the clinical features of depression moderate its adverse effects. We investigated these three issues among young adults using an office-like setting. Methods: In total, 218 subjects with a history of childhood-onset major depressive episodes (probands), 206 never-depressed full biological siblings of the probands (high-risk siblings), and 166 emotionally healthy unrelated controls received a psychiatric evaluation and three standardized-sitting BP measurements 5 min apart. Short-term BPV was defined as the maximum difference between measures (range) for each case. The statistical methods included analyses of variance/covariance, chi-square tests, and multiple regression. Results: Systolic and diastolic BP decreased over consecutive measurements (p < 0.001). After controlling for age, the probands, siblings, and controls did not differ significantly in terms of BPV. However, the number of lifetime depressive episodes did predict the diastolic BP range (p = 0.005): probands with the highest number of depressive episodes had the largest short-term diastolic BPV. Conclusions: On a group level, the adverse effects on BPV of having experienced or being at high risk for depression are not yet evident during young adulthood. However, the number of major depressive episodes, which is an index of lifetime depression burden, predicts higher BPV. Thus, BPV monitoring for young adults with clinical depression histories could be part of an early intervention program to reduce the risk of eventual cardiovascular disease.

Shared genetic basis connects smoking behaviors and bone health: insights from a genome-wide cross-trait analysis

Although the negative association of tobacco smoking with osteoporosis is well-documented, little is known regarding the shared genetic basis underlying these conditions. In this study, we aim to investigate a shared genetic architecture between smoking and heel estimated bone mineral density (eBMD), a reliable proxy for osteoporosis. We conducted a comprehensive genome-wide cross-trait analysis to identify genetic correlation, pleiotropic loci and causal relationship of smoking with eBMD, leveraging summary statistics of the hitherto largest genome-wide association studies conducted in European ancestry for smoking initiation (Nsmoker = 1 175 108, Nnonsmoker = 1 493 921), heaviness (cigarettes per day, N = 618 489), cessation (Ncurrent smoker = 304 244, Nformer smoker = 843 028), and eBMD (N = 426 824). A significant negative global genetic correlation was found for smoking cessation and eBMD (${r}_g$ = -0.051, P = 0.01), while we failed to identify a significant global genetic correlation of smoking initiation or heaviness with eBMD. Partitioning the whole genome into independent blocks, we observed 6 significant shared local signals for smoking and eBMD, with 22q13.1 showing the strongest regional genetic correlation. Such a genetic overlap was further supported by 71 pleiotropic loci identified in the cross-trait meta-analysis. Mendelian randomization identified no causal effect of smoking initiation (beta = -0.003 g/cm2, 95% CI = -0.033 to 0.027) or heaviness (beta = -0.017 g/cm2, 95% CI = -0.072 to 0.038) on eBMD, but a putative causal effect of genetic predisposition to being a current smoker was associated with a lower eBMD compared to former smokers (beta = -0.100 g/cm2, 95% CI = -0.181 to -0.018). Our study demonstrates a pronounced biological pleiotropy as well as a putative causal link between current smoking status and eBMD, providing novel insights into the primary prevention and modifiable intervention of osteoporosis by advocating individuals to avoid, reduce or quit smoking as early as possible.

Exploring pleiotropy in Mendelian randomisation analyses: What are genetic variants associated with 'cigarette smoking initiation' really capturing?

Genetic variants used as instruments for exposures in Mendelian randomisation (MR) analyses may have horizontal pleiotropic effects (i.e., influence outcomes via pathways other than through the exposure), which can undermine the validity of results. We examined the extent of this using smoking behaviours as an example. We first ran a phenome-wide association study in UK Biobank, using a smoking initiation genetic instrument. From the most strongly associated phenotypes, we selected those we considered could either plausibly or not plausibly be caused by smoking. We examined associations between genetic instruments for smoking initiation, smoking heaviness and lifetime smoking and these phenotypes in UK Biobank and the Avon Longitudinal Study of Parents and Children (ALSPAC). We conducted negative control analyses among never smokers, including children. We found evidence that smoking-related genetic instruments were associated with phenotypes not plausibly caused by smoking in UK Biobank and (to a lesser extent) ALSPAC. We observed associations with phenotypes among never smokers. Our results demonstrate that smoking-related genetic risk scores are associated with unexpected phenotypes that are less plausibly downstream of smoking. This may reflect horizontal pleiotropy in these genetic risk scores, and we would encourage researchers to exercise caution this when using these and genetic risk scores for other complex behavioural exposures. We outline approaches that could be taken to consider this and overcome issues caused by potential horizontal pleiotropy, for example, in genetically informed causal inference analyses (e.g., MR) it is important to consider negative control outcomes and triangulation approaches, to avoid arriving at incorrect conclusions.

Association between primary biliary cholangitis with diabetes and cardiovascular diseases: A bidirectional multivariable Mendelian randomization study

BACKGROUND AND AIMS

Primary biliary cholangitis (PBC) is an autoimmune disease often accompanied by multisystem damage. This study aimed to explore the causal association between genetically predicted PBC and diabetes, as well as multiple cardiovascular diseases (CVDs).

METHODS

Genome-wide association studies (GWAS) summary data of PBC in 24,510 individuals of European ancestry from the European Association for the Study of the Liver was used to identify genetically predicted PBC. We conducted 2-sample single-variable Mendelian randomization (SVMR) and multivariable Mendelian randomization (MVMR) to estimate the impacts of PBC on diabetes (N = 17,685 to 318,014) and 20 CVDs from the genetic consortium (N = 171,875 to 1,030,836).

RESULTS

SVMR provided evidence that genetically predicted PBC is associated with an increased risk of type 1 diabetes (T1D), type 2 diabetes (T2D), myocardial infarction (MI), heart failure (HF), hypertension, atrial fibrillation (AF), stroke, ischemic stroke, and small-vessel ischemic stroke. Additionally, there was no evidence of a causal association between PBC and coronary atherosclerosis. In the MVMR analysis, PBC maintained independent effects on T1D, HF, MI, and small-vessel ischemic stroke in most models.

CONCLUSION

Our findings revealed the causal effects of PBC on diabetes and 7 CVDs, and no causal relationship was detected between PBC and coronary atherosclerosis.

Causal association between cardiovascular proteins and membranous nephropathy: a bidirectional Mendelian randomization

PURPOSE

Multiple circulating proteins have been reported to participate in human diseases. However, the association between cardiovascular proteins and membranous nephropathy (MN) remained profoundly elusive.

METHODS

A bidirectional Mendelian randomization (MR) analysis was conducted to explore the causal correlation between ninety cardiovascular proteins and MN. Genome-wide association study (GWAS) data of cardiovascular proteins and MN were all from European research. Inverse variance weighted (IVW) was used as the main approach. Moreover, MR-Egger, weighted median, weighted mode, and simple mode were also performed. Cochrane's Q test, MR-Egger, and MR-PRESSO were conducted for sensitivity analysis.

RESULTS

According to IVW method, fatty acid-binding protein and thrombomodulin (TM) were identified as risk factors for MN, while a protective role was detected in tissue-type plasminogen activator. Additionally, MN was associated with an elevated level of macrophage colony-stimulating factor 1, stem cell factor, TM, and tissue factor. Reversely, MN was also correlated with a downregulated level of beta-nerve growth factor, Cathepsin D, hepatocyte growth factor, interleukin-6 receptor subunit alpha, macrophage colony-stimulating factor 1, and myeloperoxidase. In the sensitivity analysis, no significant pleiotropy and heterogeneity was detected.

CONCLUSION

This was the first study to reveal the causal association between cardiovascular proteins and MN. These specific cardiovascular proteins could be novel biomarkers for MN, and is helpful for timely identify the risk of other diseases that might result from MN. However, further clinical studies are needed to confirm our results.

Mendelian randomization identifies causal effects of major depressive disorder on accelerated aging

BACKGROUND

Evidence links major depressive disorder (MDD) with aging, but it's unclear if MDD accelerates aging and what factors mediate this transition.

METHODS

Two-sample Mendelian randomization (MR) analyses were applied to estimate the causal association between MDD and frailty index (FI), telomere length (TL), and appendicular lean mass (ALM) from available genome-wide association studies in populations of European ancestry. Furthermore, we conducted mediation MR analyses to assess the mediating effects of 31 lifestyle factors or diseases on the causal relationship between MDD and aging.

RESULTS

MDD was significantly causally associated with increased FI (βIVW = 0.23, 95 % CI = 0.18 to 0.28, p = 1.20 × 10-17), shorter TL (βIVW = -0.04, 95 % CI = -0.07 to -0.01, p = 0.01), and decreased ALM (βIVW = -0.07, 95 % CI = -0.11 to -0.03, p = 3.54 × 10-4). The mediation analysis through two-step MR revealed smoking initiation (9.09 %), hypertension (6.67 %) and heart failure (5.36 %) mediated the causal effect of MDD on FI. Additionally, alcohol use disorders and alcohol dependence on the causal relationship between MDD and TL were found to be 17.52 % and 17.13 % respectively.

LIMITATIONS

Confounding, statistical power, and Euro-centric focus limit generalization.

CONCLUSION

Overall, individuals with MDD may be at a higher risk of experiencing premature aging, and this risk is partially influenced by the pathways involving smoking, alcohol use, and cardiovascular health. It underscores the importance of early intervention and comprehensive health management in individuals with MDD to promote healthy aging and overall well-being.

Gene × environment effects and mediation involving adverse childhood events, mood and anxiety disorders, and substance dependence

Adverse childhood events (ACEs) contribute to the development of mood and anxiety disorders and substance dependence. However, the extent to which these effects are direct or indirect and whether genetic risk moderates them is unclear. We examined associations among ACEs, mood/anxiety disorders and substance dependence in 12,668 individuals (44.9% female, 42.5% African American/Black, 42.1% European American/white). Using latent variables for each phenotype, we modelled direct and indirect associations of ACEs with substance dependence, mediated by mood/anxiety disorders (the forward or 'self-medication' model) and of ACEs with mood/anxiety disorders, mediated by substance dependence (the reverse or 'substance-induced' model). In a subsample, we tested polygenic scores for the substance dependence and mood/anxiety disorder factors as moderators in the mediation models. Although there were significant indirect paths in both directions, mediation by mood/anxiety disorders (the forward model) was greater than that by substance dependence (the reverse model). Greater genetic risk for substance use disorders was associated with a weaker direct association between ACEs and substance dependence in both ancestry groups (reflecting gene × environment interactions) and a weaker indirect association in European-ancestry individuals (reflecting moderated mediation). We found greater evidence that substance dependence reflects self-medication of mood/anxiety disorders than that mood/anxiety disorders are substance induced. Among individuals at higher genetic risk for substance dependence, ACEs were less associated with that outcome. Following exposure to ACEs, multiple pathways appear to underlie the associations between mood/anxiety disorders and substance dependence. Specification of these pathways could inform individually targeted prevention and treatment approaches.

Impact of healthy lifestyle on the incidence and progression trajectory of mental disorders: A prospective study in the UK Biobank

BACKGROUND

Healthier lifestyle decreased the risk of mental disorders (MDs) such as depression and anxiety. However, research on the effects of a comprehensive healthy lifestyle on their progression is lacking.

METHODS

385,704 individuals without baseline MDs from the UK Biobank cohort were included. A composite healthy lifestyle score was computed by assessing alcohol intake, smoking status, television viewing time, physical activity, sleep duration, fruit and vegetable intake, oily fish intake, red meat intake, and processed meat intake. Follow-up utilized hospital and death register records. Multistate model was used to examine the role of healthy lifestyle on the progression of specific MDs, while a piecewise Cox regression model was utilized to assess the influence of healthy lifestyle across various phases of disease progression.

RESULTS

Higher lifestyle score reduced risks of transitions from baseline to anxiety and depression, as well as from anxiety and depression to comorbidity, with corresponding hazard ratios (HR) and 95 % confidence intervals (CI) of 0.94 (0.93, 0.95), 0.90 (0.89, 0.91), 0.94 (0.91, 0.98), and 0.95 (0.92, 0.98), respectively. Healthier lifestyle decreased the risk of transitioning from anxiety to comorbidity within 2 years post-diagnosis, with HR 0.93 (0.88, 0.98). Higher lifestyle scores at 2-4 years and 4-6 years post-depression onset were associated with reduced risk of comorbidity, with HR 0.93 (0.87, 0.99) and 0.92 (0.86, 0.99), respectively.

LIMITATION

The generalizability to other ethnic groups is limited.

CONCLUSION

This study observed a protective role of holistic healthy lifestyle in the trajectory of MDs and contributed to identifying critical progression windows.

A Causal Model for Primary Prevention of Cardiovascular Disease: The Health Economic Model for the Primary Prevention of Cardiovascular Disease

OBJECTIVES

Our objective was to design and develop an open-source model capable of simulating interventions for primary prevention of cardiovascular disease (CVD) that incorporated the cumulative effects of risk factors (eg, cholesterol years or blood-pressure years) to enhance health economic modeling in settings which clinical trials are not possible.

METHODS

We reviewed the literature to design the model structure by selecting the most important causal risk factors for CVD-low-density lipoprotein-cholesterol (LDL-C), systolic blood pressure (SBP), smoking, diabetes, and lipoprotein (a) (Lp(a))-and most common CVDs-myocardial infarction and stroke. The epidemiological basis of the model involves the simulation of risk factor trajectories, which are used to modify CVD risk via causal effect estimates derived from Mendelian randomization. LDL-C, SBP, Lp(a), and smoking all have cumulative impacts on CVD risk, which were incorporated into the health economic model. The data for the model were primarily sourced from the UK Biobank study. We calibrated the model using clinical trial data and validated the model against the observed UK Biobank data. Finally, we performed an example health economic analysis to demonstrate the utility of the model. The model is open source.

RESULTS

The model performed well in all validation tests. It was able to produce interpretable and plausible (consistent with expectations of the existing literature) results from an example health economic analysis.

CONCLUSIONS

We have constructed an open-source health economic model capable of incorporating the cumulative effect of LDL-C (ie, cholesterol years), SBP (SBP-years), Lp(a), and smoking on lifetime CVD risk.

Association between periodontal disease and schizophrenia: a bidirectional two-sample Mendelian randomization study

The connection between periodontal disease (PD) and schizophrenia (SCZ) has been reported in observational studies, but it remains unclear. This research aims to examine the bidirectional causal impacts between PD and SCZ. The FinnGen consortium supplied summarized data on PD for 346,731 individuals (87,497 cases and 259,234 controls) of Finnish ancestry, and information on SCZ was acquired from the OpenGWAS repository, encompassing 127,906 individuals (52,017 cases and 75,889 controls) of European ancestry. Next, we conducted Mendelian randomization (MR) analysis to establish a causal inference relationship between PD and SCZ. The inverse variance weighted (IVW) method was utilized as the primary analysis. Additionally, some sensitivity analyses were utilized to verify the stability of the results. The analysis of IVW results indicated no impact of PD on SCZ (IVW OR = 1.10, 95% CI 0.97-1.24, P = 0.14). Nevertheless, the inverse relationship between PD and SCZ was identified through reverse MR analysis (IVW OR = 1.03, 95% CI 1.01-1.05, P = 0.002). The findings from MR-Egger, weighted median, simple mode, and weighted mode approaches aligned with the outcomes of the IVW method. Based on sensitivity analyses, horizontal pleiotropy is unlikely to distort causal estimates. This study presented the initial proof of a genetic causal relationship between SCZ and PD, albeit with a minimal impact. Further exploration is needed to gain a deeper understanding of this relationship. Furthermore, no genetic causal relationship between PD and SCZ was identified.

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.

Bidirectional Mendelian Randomization of Causal Relationship between Inflammatory Cytokines and Different Pathological Types of Lung Cancer

Prior research has proposed a potential association between lung cancer and inflammatory cytokines, yet the specific causal relationship remains unclear, especially across various lung cancer pathologies. This study utilized bidirectional Mendelian randomization (MR) to explore these causal connections, unveiling novel insights. Our research revealed distinctive inflammatory cytokine profiles for each subtype of lung cancer and identified potential biomarkers that could refine diagnostic and therapeutic approaches. We applied two-sample Mendelian randomization, leveraging genetic variance data from three extensive genome-wide association studies (GWAS) focusing on different lung cancer types (lung adenocarcinoma: 1590 cases and 314,193 controls of healthy individuals of European descent; lung squamous cell carcinoma: 1510 cases and 314,193 controls of European ancestry; small cell lung cancer: 717 cases and 314,193 controls of European ancestry). A separate GWAS summary on inflammatory cytokines from 8,293 healthy participants was also included. The inverse variance weighting method was utilized to examine causal relationships, with robustness confirmed through multiple sensitivity analyses, including MR-Egger, weighted median, and MR-PRESSO. Our analysis revealed that elevated levels of IL_1RA were associated with an increased risk of lung adenocarcinoma (OR: 1.29, 95% CI: 1.02-1.64, p = 0.031), while higher MCP_1_MCAF levels correlated with a decreased risk of lung squamous cell carcinoma (OR: 0.77, 95% CI: 0.61-0.98, p = 0.031). Furthermore, IL_10, IL_13, and TRAIL levels were positively associated with lung squamous cell carcinoma risk (IL_10: OR: 1.27, 95% CI: 1.06-1.53, p = 0.012; IL_13: OR: 1.15, 95% CI: 1.06-1.53, p = 0.036; TRAIL: OR: 1.15, 95% CI: 1.06-1.53, p = 0.043). No association was found between inflammatory cytokine levels and small cell lung cancer development, whereas SDF_1A and B-NGF were linked to an increased risk of this cancer type (SDF_1A: OR: 1.13, 95% CI: 1.05-1.21, p = 0.001; B-NGF: OR: 1.13, 95% CI: 1.01-1.27, p = 0.029). No significant relationship was observed between the 41 circulating inflammatory cytokines and lung adenocarcinoma or squamous cell carcinoma development. Our findings indicate distinct associations between specific inflammatory cytokines and different types of lung cancer. Elevated IL_1RA levels are a risk marker for lung adenocarcinoma, whereas higher MCP_1_MCAF levels appear protective against lung squamous cell carcinoma. Conversely, elevated levels of IL_10, IL_13, and TRAIL are linked with an increased risk of lung squamous cell carcinoma. The relationships of SDF_1A and B-NGF with small-cell lung cancer highlight the complexity of inflammatory markers in cancer development. This study provides a nuanced understanding of the role of inflammatory cytokines in lung cancer, underscoring their potential in refining diagnosis and treatment strategies.

Exploring causal correlations between circulating cytokines and atopic dermatitis: a bidirectional two-sample Mendelian randomization study

Objectives

Numerous observational studies have reported associations between circulating cytokines and atopic dermatitis (AD); however, the causal relationships between them remain unclear. To explore the causal correlations and direction of causal effects between AD and levels of 91 circulating cytokines.

Methods

Two-sample Mendelian randomization (MR) analyses were conducted to examine the causal relationships between 91 circulating cytokines and AD using summary statistics from genome-wide association studies (GWAS). Reverse MR analyses were performed to investigate reverse causation. Pleiotropy and heterogeneity tests were conducted to assess the robustness of the findings. Additional transcriptome database and clinical peripheral blood mononuclear cells (PBMCs) samples were utilized to validate the results of MR analyses.

Results

Levels of interleukin (IL)-13, IL-18 Receptor 1, Tumor necrosis factor ligand superfamily member 14 (TNFSF14), TNF-related activation-induced cytokine (TRANCE), C-X-C motif chemokine (CXCL)11, IL-33, TNF-beta and CD5 were suggestively associated with the risk of AD (odds ratio, OR: 1.202, 95% CI: 1.018-1.422, p = 0.030; OR: 1.029, 95% CI: 1.029-1.157, p = 0.004; OR: 1.159, 95% CI: 1.018-1.320, p = 0.026; OR: 1.111, 95% CI: 1.016-1.214, p = 0.020; OR: 0.878, 95% CI: 0.783-0.984, p = 0.025; OR: 0.809, 95% CI: 0.661-0.991, p = 0.041; OR: 0.945, 95% CI: 0.896-0.997, p = 0.038; OR: 0.764, 95% CI: 0.652-0.895, p = 8.26e-04). In addition, levels of cytokines including Axin-1, CXCL5, CXCL10, Oncostatin-M (OSM), Sulfotransferase 1A1 (SULT1A1) and TNFSF14 were suggested to be consequences of AD (Beta: -0.080, p = 0.016; Beta: -0.062, p = 0.036; Beta: -0.066, p = 0.049; Beta: -0.073, p = 0.013; Beta: -0.089, p = 0.008; Beta: -0.079, p = 0.031). IL-13, IL-18R1, TNFSF14, and TRANCE were upregulated in both lesional skin biopsies and PBMCs from AD patients.

Conclusion

The study indicates that several cytokines, including IL-13, IL-18R1, TNFSF14, TRANCE, CXCL11, IL-33, TNF-beta, and CD5, are upstream of AD development, whereas a few circulating cytokines are potentially downstream in the development of AD.

Genetic Associations of Anhedonia: Insights into Overlap of Mental and Somatic Disorders

BACKGROUND

Anhedonia is characterized by a reduced ability to anticipate, experience, and/or learn about pleasure. This phenomenon has a transdiagnostic nature and is one of the key symptoms of mood disorders, schizophrenia, addictions, and somatic conditions.

AIM

To evaluate the genetic architecture of anhedonia and its overlap with other mental disorders and somatic conditions.

METHODS

We performed a genome-wide association study of anhedonia on a sample of 4,520 individuals from a Russian non-clinical population. Using the available summary statistics, we calculated polygenic risk scores (PRS) to investigate the genetic relationship between anhedonia and other psychiatric or somatic phenotypes.

RESULTS

No variants with a genome-wide significant association were identified. PRS for major depression, bipolar disorder, and schizophrenia were significantly associated with anhedonia. Conversely, no significant associations were found between PRS for anxiety and anhedonia, which aligns well with existing clinical evidence. None of the PRS for somatic phenotypes attained a significance level after correction for multiple comparisons. A nominal significance for the anhedonia association was determined for omega-3 fatty acids, type 2 diabetes mellitus, and Crohn's disease.

CONCLUSION

Anhedonia has a complex polygenic architecture, and its presence in somatic diseases or normal conditions may be due to a genetic predisposition to mood disorders or schizophrenia.

Association between tobacco smoke exposure and depression: the NHANES 2005-2018 and Mendelian randomization study

OBJECTIVE

The relationship between tobacco smoke exposure (TSE) and depression is controversial. This study combined observational research and Mendelian randomization (MR) to explore the relationship of depression with both smoking status and cotinine levels.

METHOD

We collected relevant data from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2018, and used weighted multifactorial logistic regression modelling to assess the correlation between TSE and depression, and assessed the causal relationship of depression with both smoking status and cotinine levels by MR.

RESULT

Current smokers had the highest risk of depression (OR 1.94; P < 0.01); there was a positive trend for correlation between daily smoking and depression (OR 1.66; P for trend < 0.01). Serum ketamine levels above 3.00 ng/ml had a higher risk of depression (OR 2.13; P < 0.001). MR results showed that current smoking (OR = 4.66; P < 0.001) and previous smoking (OR 2.09; P < 0.01) were risk factors for the onset of depression, and that there was no causal association between cotinine levels and depression.

CONCLUSION

Smoking is significantly associated with depression and plays a potential causal role in the development of depression. Cotinine was significantly associated with depression, however MR results showed no causal relationship between cotinine and depression.

Association between biological ageing and periodontitis: Evidence from a cross-sectional survey and multi-omics Mendelian randomization analysis

AIM

To investigate the relationship and potential causality between biological ageing and periodontitis.

MATERIALS AND METHODS

We obtained the National Health and Nutrition Examination Survey (NHANES) and genome-wide association study (GWAS) summary statistics as well as single-cell sequencing data. Multivariate regression analysis based on cross-sectional data, Mendelian randomization (MR) and multi-omics integration analysis were employed to explore the causal association and potential molecular mechanisms between biological ageing and periodontitis. Additionally, two-step MR mediation analysis explored the risk factors in biological ageing-mediated periodontitis.

RESULTS

We analysed data from 3189 participants in the NHANES data and found that higher biological age was associated with increased risk of periodontitis. MR analyses revealed causal associations between biological age measures and periodontitis risk. Frailty (odds ratio [OR] = 2.08, 95% confidence interval [CI]: 1.04-4.18, p = .039) and GrimAge acceleration (OR = 1.16, 95% CI: 1.01-1.32, p = .033) were causally associated with periodontitis risk, and these results were validated in a large-scale meta-periodontitis GWAS dataset. Additionally, the risk effects of body mass index, waist circumference and lifetime smoking on periodontitis were partially mediated by frailty and GrimAge acceleration.

CONCLUSIONS

Evidence from cross-sectional survey and MR analysis suggests that biological ageing increases the risk of periodontitis. Additionally, improving the associated risk factors can help prevent both ageing and periodontitis.

Gastroesophageal Reflux and Chronic Rhinosinusitis: A Mendelian Randomization Study

OBJECTIVE

Chronic rhinosinusitis (CRS) is associated with gastroesophageal reflux (GERD). However, the causal relationship is controversial. We conducted a two-sample Mendelian Randomization (MR) analysis to explore this potential association.

METHODS

Based on genome-wide association studies (GWAS), a univariable MR was performed to explore the causal relationship of GERD with CRS. Instrumental variables (IVs) pertinent to anti-GERD treatment were employed as a means of validation. The primary MR outcome was established using an inverse variance weighted (IVW) method, supplemented by multiple sensitivity analyses. Subsequently, a multivariable MR was conducted to account for potential confounding variables, thereby ascertaining a direct effect of GERD on CRS. Finally, a network MR analysis was carried out to elucidate the mediating role of asthma in the relationship between GERD and CRS.

RESULTS

The univariable MR demonstrated an association between GERD and an elevated risk of CRS (IVW OR = 1.30, 95% CI = 1.18-1.45, p = 4.19 × 10-7). Omeprazole usage was associated with a reduction in CRS risk (IVW OR = 0.64, 95% CI = 0.42-0.98, p = 0.039). The causal relationship between GERD and CRS remained after adjusting for potential confounders, such as smoking characteristics, body mass index, asthma, allergic rhinitis, in the multivariable MR analysis. Besides, the proportion of the causal effect of GERD on CRS mediated by asthma was 19.65% (95% CI = 2.69%-36.62%).

CONCLUSION

GERD was independently associated with an increased risk of CRS. The mediating role of asthma between GERD and CRS also reveals that GERD is one of the mechanisms underlying unified airway disease.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:3086-3092, 2024.

Risk Factors for Pelvic Organ Prolapse: Wide-Angled Mendelian Randomization Analysis

INTRODUCTION AND HYPOTHESIS

We hypothesized that some metabolic factors, lifestyle factors, and socioeconomic factors may have a causal effect on pelvic organ prolapse (POP).

METHODS

We selected instruments from corresponding genome-wide association studies (GWAS), which identified independent single nucleotide polymorphisms strongly associated with 12 potential risk factors. Summary statistics for POP were derived from two GWAS datasets, serving for discovery and replication stage. The primary analysis involved the use of the inverse-variance weighting mendelian randomization (MR) method, with additional sensitivity MR analyses conducted.

RESULTS

The univariable mendelian randomization (UVMR) analysis in both the discovery and replication stage provided evidence for significant causal effects between higher waist-to-hip ratio adjusted for body mass index (WHRadjBMI) levels, lower high-density lipoprotein cholesterol (HDL-C) levels, and lower educational attainment and higher POP risk, as well as a suggestive positive causal effect between triglycerides and POP. The multivariable mendelian randomization (MVMR) analysis showed that only HDL-C among the three blood lipid fractions could reduce the risk of POP. Mediation analysis indicated that HDL-C may partially mediate the effect of WHRadjBMI on POP risk, and the causal effect between educational attainment and POP may be mediated through WHRadjBMI and HDL-C.

CONCLUSIONS

Our study's evidence supported a causal relationship between WHRadjBMI, triglycerides, HDL-C, educational attainment, and POP risk. This highlights that clinicians may guide the general female population to control obesity and blood lipid levels to reduce the risk of POP.

Life-Course Associations Between Smoking and Depressive Symptoms. A 30-Year Finnish Follow-up Study

INTRODUCTION

Relatively little is known about whether the association between smoking and depressive symptoms changes with age and how the trajectories of smoking and depressive symptoms are intertwined during the life course. In this population-based study, these associations were examined from young adulthood to middle age.

METHODS

Participants of a Finnish cohort study (N = 1955) were assessed at the ages of 22, 32, 42, and 52 using questionnaires covering daily smoking (yes/no) and the short 13-item Beck Depression Inventory. Longitudinal latent class and longitudinal latent profile analyses were used to identify life course trajectories of smoking and depressive symptoms.

RESULTS

The proportions of daily smokers decreased, while levels of depressive symptoms increased among both females and males from age 22 to 52 years. Smoking was associated with higher levels of depressive symptoms from age 22 to 42 years, while not at 52. Associations among males prevailed when adjusting for education, marital status, and alcohol use. Four life course classes of daily smoking (nonsmokers, decreasing prevalence of smoking, persistent smokers, and increasing prevalence of smoking) and four trajectories of depressive symptoms (low, increasing/moderate, decreasing/moderate, and high) were identified. In males, persistent daily smokers (relative risk ratio (RRR) = 4.5, 95% confidence interval (CI): 2.2 to 9.2) and those in the class with increasing smoking prevalence (RRR = 3.2, 95% CI: 1.1 to 9.1) had an increased risk of belonging to the high depressive symptoms profile. In females these associations were nonsignificant.

CONCLUSIONS

Compared to females, the relationship between smoking and depressive symptoms seems more robust among males during adulthood. Specifically, males smoking persistently from young adulthood to middle age have an increased risk of high depressive symptoms trajectory.

IMPLICATIONS

This population-based cohort with 30 years of follow-up showed that the life course trajectories of daily smoking and depressive symptoms are associated. Persistent daily smokers and those starting late had an increased risk of belonging to the profile with constantly high levels of depressive symptoms during the life course. However, these associations were statistically significant only in males. Actions should be strengthened, especially in males, to prevent smoking initiation, to help smoking cessation, and to identify and treat depression in smokers with significant depressive symptoms.

Exploring the Bidirectional Causal Pathways Between Smoking Behaviors and Headache: A Mendelian Randomization Study

INTRODUCTION

Although observational data suggest a relationship between headache and smoking, there remain questions about causality. Smoking may increase headache risk, individuals may smoke to alleviate headaches, or smoking and headache may share common risk factors. Mendelian randomization (MR) is a method that uses genetic variants as instruments for making causal inferences about an exposure and an outcome.

AIMS AND METHODS

First, we conducted logistic regression of observational data in UK Biobank assessing the association between smoking behaviors (smoking status, cigarettes per day amongst daily smokers, and lifetime smoking score) on the risk of self-reported headache (in the last month and for more than 3 months). Second, we used genetic instruments for smoking behaviors and headache (identified in independent genome-wide association studies [GWAS]) to perform bidirectional MR analysis.

RESULTS

Observationally, there is a weak association between smoking behavior and experiencing headache, with increased cigarettes per day associated with increased headache risk. In the MR analysis, genetic liability to smoking initiation and lifetime smoking increased odds of headache in the last month but not odds of headaches lasting more than 3 months. In the opposite direction, there was weak evidence for higher genetic liability to headaches decreasing the chance of quitting.

CONCLUSIONS

There was weak evidence for a partially bidirectional causal relationship between smoking behaviors and headache in the last month. Given this relationship is distinct from smoking heaviness, it suggests headache and smoking may share common risk factors such as personality traits.

IMPLICATIONS

Using MR, this study addresses the uncertainty regarding the observed relationship between headache and smoking. There was evidence for weak causal effects of smoking initiation and lifetime smoking (but not smoking heaviness) on likelihood of experiencing headache in the last month, but not over a prolonged period of more than 3 months. Those with higher genetic liability to headaches were also less likely to successfully stop smoking. This partially bidirectional causal relationship distinct from smoking heaviness suggests that observed associations are unlikely due to biological effects of tobacco smoke exposure and may be explained by shared personality traits.

Comparison of caffeine consumption behavior with plasma caffeine levels as exposure measures in drug-target Mendelian randomization

Mendelian randomization is an epidemiological technique that can explore the potential effect of perturbing a pharmacological target. Plasma caffeine levels can be used as a biomarker to measure the pharmacological effects of caffeine. Alternatively, this can be assessed using a behavioral proxy, such as average number of caffeinated drinks consumed per day. Either variable can be used as the exposure in a Mendelian randomization investigation, and to select which genetic variants to use as instrumental variables. Another possibility is to choose variants in gene regions with known biological relevance to caffeine level regulation. These choices affect the causal question that is being addressed by the analysis, and the validity of the analysis assumptions. Further, even when using the same genetic variants, the sign of Mendelian randomization estimates (positive or negative) can change depending on the choice of exposure. Some genetic variants that decrease caffeine metabolism associate with higher levels of plasma caffeine, but lower levels of caffeine consumption, as individuals with these variants require less caffeine consumption for the same physiological effect. We explore Mendelian randomization estimates for the effect of caffeine on body mass index, and discuss implications for variant and exposure choice in drug target Mendelian randomization investigations.

The causal relationship between smoking, alcohol consumption, and renal clear cell carcinoma: a Mendelian randomization study

Introduction: Observational studies have found a correlation between the consumption of tobacco and alcohol and the likelihood of developing renal cell carcinoma. However, whether these associations indicate causal relationships is unclear. Methods: To establish if these connections indicate causal relationships, we performed a Mendelian Randomization (MR) analysis using a two-sample approach. For the number of daily cigarettes, lifetime smoking index, smoking initiation, and weekly drinking, we employed 44, 108, 174, and 76 single nucleotide polymorphisms (SNPs) as instrumental variables. Outcome data were obtained from the FinnGen Alliance, which included a combined total of 429,290 individuals. The MR analysis was conducted using the inverse-variance weighted (IVW) method to estimate causal effects. To address potential violations of MR assumptions due to directional pleiotropy, we performed MR-Egger regression and MR-PRESSO (Mendelian Randomization Pleiotropy RESidual Sum and Outlier) analysis. Results: Genetically influenced smoking initiation was directly associated with the risk of developing renal cell carcinoma (OR = 1.55, 95% CI: 1.04-2.33; p = 0.03). No causal relationship was found between daily cigarette consumption and lifetime smoking index with the risk of renal cell cancer. Genetic predisposition for weekly alcohol consumption showed a reduced risk of renal cell cancer (OR = 0.45, 95% CI: 0.26-0.81; p = 0.007). Discussion: Our study suggests a potential causal relationship between alcohol consumption and reduced risk of renal cell cancer, while no such association was observed with smoking. Further research is needed to confirm these findings.

Analysis of patient health questionnaire-9 (PHQ-9) based depression prevalence according to a discordance between quantitative urinary cotinine levels and self-report of second-hand smoke exposure among adults: A cross-sectional study

Background

Second-hand smoke (SHS) exposure appears to be more common among individuals with depression. However, self-report of SHS exposure is an inaccurate classification compared to confirming SHS exposure using urinary cotinine (UC). Additionally, the dose-response relationship between depression and UC is controversial.

Methods

The severe stress rate and depression prevalence was estimated among 14530 Korean participants aged ≥19 years using data patient health questionnaire-9 (PHQ-9) and on UC from the Korean National Health and Nutrition Examination Survey. Measured UCs were divided into four categories: UC- (≤0.3 μg/L), UC± (0.4 μg/L-0.9 μg/L), UC+ (1.0 μg/L-11.9 μg/L), and UC++ (≥12.0 μg/L).

Results

About 55.0 % participants were female and participants' mean age was 51.1 years. Non-smokers were 80.3 %. Among non-smokers, non-SHS exposure participants (SR-) and SHS exposure participants (SR+) were 83.0 % and 17.0 %, respectively. When UC- was used as the reference subgroup, the UC++ subgroup showed a higher depression prevalence, whereas the UC ± subgroup showed a lower prevalence. In the same UC categories, the depression prevalence and severe stress rate were higher among females than among males. Furthermore, the SR + subgroup had a higher severe stress rate than the SR- subgroup.

Conclusions

Our study showed a paradoxical reduction in the depression prevalence and severe stress rate in the UC ± subgroup compared to the UC- subgroup. Additionally, the dose-response relationship between the SHS exposure biomarker and the depression prevalence was not linear. Our study indicates that an emotional stress-based model may be more appropriate for explaining the relationship between depression and SHS exposure.

Genetically Informed Study Highlights Income-Independent Effect of Schizophrenia Liability on Mental and Physical Health

BACKGROUND AND HYPOTHESIS

Individuals with schizophrenia (SCZ) suffer from comorbidities that substantially reduce their life expectancy. Socioeconomic inequalities could contribute to many of the negative health outcomes associated with SCZ.

STUDY DESIGN

We investigated genome-wide datasets related to SCZ (52 017 cases and 75 889 controls) from the Psychiatric Genomics Consortium, household income (HI; N = 361 687) from UK Biobank, and 2202 medical endpoints assessed in up to 342 499 FinnGen participants. A phenome-wide genetic correlation analysis of SCZ and HI was performed, also assessing whether SCZ genetic correlations were influenced by the HI effect on SCZ. Additionally, SCZ and HI direct effects on medical endpoints were estimated using multivariable Mendelian randomization (MR).

STUDY RESULTS

SCZ and HI showed overlapping genetic correlations with 70 traits (P < 2.89 × 10-5), including mental health, substance use, gastrointestinal illnesses, reproductive outcomes, liver diseases, respiratory problems, and musculoskeletal phenotypes. SCZ genetic correlations with these traits were not affected by the HI effect on SCZ. Considering Bonferroni multiple testing correction (P < 7.14 × 10-4), MR analysis indicated that SCZ and HI may affect medical abortion (SCZ OR = 1.07; HI OR = 0.78), panic disorder (SCZ OR = 1.20; HI OR = 0.60), personality disorders (SCZ OR = 1.31; HI OR = 0.67), substance use (SCZ OR = 1.2; HI OR = 0.68), and adjustment disorders (SCZ OR = 1.18; HI OR = 0.78). Multivariable MR analysis confirmed that SCZ effects on these outcomes were independent of HI.

CONCLUSIONS

The effect of SCZ genetic liability on mental and physical health may not be strongly affected by socioeconomic differences. This suggests that SCZ-specific strategies are needed to reduce negative health outcomes affecting patients and high-risk individuals.

Effect of smoking on prostate cancer: Results from the National Health and Nutrition Examination Survey 2003-2018 and Mendelian randomization analyses

INTRODUCTION

The controversial relationship between smoking and prostate cancer (PCa) risk prompted us to conduct a cross-sectional study using the National Health and Nutrition Examination Survey (NHANES) database and apply Mendelian randomization (MR) analyses in order to clarify the possible causal effect of smoking on PCa risk.

METHODS

Using univariate and multivariate logistic regression methods, a secondary analysis of the pooled 2003-2018 NHANES dataset was performed to explore the association between smoking and PCa risk. Propensity-score matching was used to reduce selection bias. Then, we conducted subsequent MR analysis study to investigate the potential causal effect of smoking on PCa risk, with genetic variants of four exposure factors including the lifetime smoking index, light smoking, smoking initiation, and the amount of smoking per day obtained from genome-wide association studies, and PCa summary statistics obtained from three database populations. Inverse-variance weighting was the primary analytical method, and weighted median and MR-Egger regression were used for sensitivity analyses. The MR results for the three PCa databases were combined using meta-analysis.

RESULTS

The study included 16073 NHANES subjects, comprising 554 with PCa and 15519 without PCa. Logistic regression before and after matching did not reveal any significant association. Meta-analysis of the MR results also did not support an association of PCa risk with lifetime smoking index (OR=0.95; 95% CI: 0.83-1.09), light smoking (OR=1.00; 95% CI: 0.95-1.06), smoking initiation (OR=0.99, 95% CI=0.99-1.00), or the amount of smoking per day (OR=1.00; 95% CI: 0.99-1.00) and PCa risk.

CONCLUSIONS

There was no evidence for an association between smoking and the risk of PCa. Further studies are needed to determine if there are any associations of other forms of smoking with the risk of PCa at different stages.

Distinct biological signature and modifiable risk factors underlie the comorbidity between major depressive disorder and cardiovascular disease

Major depressive disorder (MDD) and cardiovascular disease (CVD) are often comorbid, resulting in excess morbidity and mortality. Here we show that CVDs share most of their genetic risk factors with MDD. Multivariate genome-wide association analysis of shared genetic liability between MDD and atherosclerotic CVD revealed seven loci and distinct patterns of tissue and brain cell-type enrichments, suggesting the involvement of the thalamus. Part of the genetic overlap was explained by shared inflammatory, metabolic and psychosocial or lifestyle risk factors. Our data indicated causal effects of genetic liability to MDD on CVD risk, but not from most CVDs to MDD, and showed that the causal effects were partly explained by metabolic and psychosocial or lifestyle factors. The distinct signature of MDD-atherosclerotic CVD comorbidity suggests an immunometabolic subtype of MDD that is more strongly associated with CVD than overall MDD. In summary, we identified biological mechanisms underlying MDD-CVD comorbidity and modifiable risk factors for prevention of CVD in individuals with MDD.

Estimating causality between smoking and abdominal obesity by Mendelian randomization

BACKGROUND AND AIMS

Smokers tend to have a lower body weight than non-smokers, but also more abdominal fat. It remains unclear whether or not the relationship between smoking and abdominal obesity is causal. Previous Mendelian randomization (MR) studies have investigated this relationship by relying upon a single genetic variant for smoking heaviness. This approach is sensitive to pleiotropic effects and may produce imprecise causal estimates. We aimed to estimate causality between smoking and abdominal obesity using multiple genetic instruments.

DESIGN

MR study using causal analysis using summary effect estimates (CAUSE) and latent heritable confounder MR (LHC-MR) methods that instrument smoking using genome-wide data, and also two-sample MR (2SMR) methods.

SETTING

Genome-wide association studies (GWAS) summary statistics from participants of European ancestry, obtained from the GWAS and Sequencing Consortium of Alcohol and Nicotine use (GSCAN), Genetic Investigation of Anthropometric Traits (GIANT) Consortium and the UK Biobank.

PARTICIPANTS

We used GWAS results for smoking initiation (n = 1 232 091), life-time smoking (n = 462 690) and smoking heaviness (n = 337 334) as exposure traits, and waist-hip ratio (WHR) and waist and hip circumferences (WC and HC) (n up to 697 734), with and without adjustment for body mass index (adjBMI), as outcome traits.

MEASUREMENTS

Smoking initiation, life-time smoking, smoking heaviness, WHR, WC, HC, WHRadjBMI, WCadjBMI and HCadjBMI.

FINDINGS

Both CAUSE and LHC-MR indicated a positive causal effect of smoking initiation on WHR (0.13 [95% confidence interval (CI) = 0.10, 0.16 and 0.49 (0.41, 0.57), respectively] and WHRadjBMI (0.07 (0.03, 0.10) and 0.31 (0.26, 0.37). Similarly, they indicated a positive causal effect of life-time smoking on WHR [0.35 (0.29, 0.41) and 0.44 (0.38, 0.51)] and WHRadjBMI [0.18 (0.13, 0.24) and 0.26 (0.20, 0.31)]. In follow-up analyses, smoking particularly increased visceral fat. There was no evidence of a mediating role by cortisol or sex hormones.

CONCLUSIONS

Smoking initiation and higher life-time smoking may lead to increased abdominal fat distribution. The increase in abdominal fat due to smoking is characterized by an increase in visceral fat. Thus, efforts to prevent and cease smoking can have the added benefit of reducing abdominal fat.

Multi-ancestry meta-analysis of tobacco use disorder identifies 461 potential risk genes and reveals associations with multiple health outcomes

Tobacco use disorder (TUD) is the most prevalent substance use disorder in the world. Genetic factors influence smoking behaviours and although strides have been made using genome-wide association studies to identify risk variants, most variants identified have been for nicotine consumption, rather than TUD. Here we leveraged four US biobanks to perform a multi-ancestral meta-analysis of TUD (derived via electronic health records) in 653,790 individuals (495,005 European, 114,420 African American and 44,365 Latin American) and data from UK Biobank (ncombined = 898,680). We identified 88 independent risk loci; integration with functional genomic tools uncovered 461 potential risk genes, primarily expressed in the brain. TUD was genetically correlated with smoking and psychiatric traits from traditionally ascertained cohorts, externalizing behaviours in children and hundreds of medical outcomes, including HIV infection, heart disease and pain. This work furthers our biological understanding of TUD and establishes electronic health records as a source of phenotypic information for studying the genetics of TUD.

Defining a vitamin A5/X specific deficiency - vitamin A5/X as a critical dietary factor for mental health

A healthy and balanced diet is an important factor to assure a good functioning of the central and peripheral nervous system. Retinoid X receptor (RXR)-mediated signaling was identified as an important mechanism of transmitting major diet-dependent physiological and nutritional signaling such as the control of myelination and dopamine signalling. Recently, vitamin A5/X, mainly present in vegetables as provitamin A5/X, was identified as a new concept of a vitamin which functions as the nutritional precursor for enabling RXR-mediated signaling. The active form of vitamin A5/X, 9-cis-13,14-dehydroretinoic acid (9CDHRA), induces RXR-activation, thereby acting as the central switch for enabling various heterodimer-RXR-signaling cascades involving various partner heterodimers like the fatty acid and eicosanoid receptors/peroxisome proliferator-activated receptors (PPARs), the cholesterol receptors/liver X receptors (LXRs), the vitamin D receptor (VDR), and the vitamin A(1) receptors/retinoic acid receptors (RARs). Thus, nutritional supply of vitamin A5/X might be a general nutritional-dependent switch for enabling this large cascade of hormonal signaling pathways and thus appears important to guarantee an overall organism homeostasis. RXR-mediated signaling was shown to be dependent on vitamin A5/X with direct effects for beneficial physiological and neuro-protective functions mediated systemically or directly in the brain. In summary, through control of dopamine signaling, amyloid β-clearance, neuro-protection and neuro-inflammation, the vitamin A5/X - RXR - RAR - vitamin A(1)-signaling might be "one of" or even "the" critical factor(s) necessary for good mental health, healthy brain aging, as well as for preventing drug addiction and prevention of a large array of nervous system diseases. Likewise, vitamin A5/X - RXR - non-RAR-dependent signaling relevant for myelination/re-myelination and phagocytosis/brain cleanup will contribute to such regulations too. In this review we discuss the basic scientific background, logical connections and nutritional/pharmacological expert recommendations for the nervous system especially considering the ageing brain.

Genetic liability to elevated circulating IP-10, IFNγ and SCGFβ levels in relation to thoracic aortic aneurysm: A mendelian randomization study

Inflammation is associated with thoracic aortic aneurysm (TAA) but the effects of each circulating inflammatory factor on TAA remain unclear. In this study, we explored the relationship between circulating inflammatory factors and TAA risk using Mendelian randomization (MR) approach based on summary statistics from the latest genome-wide association study (GWAS) of 41 circulating inflammatory factors in 8293 Finns and a GWAS involving 1351 TAA cases and 18,295 controls of European ancestry. In univariable MR, higher interferon gamma-induced protein 10 (IP-10) levels, higher interferon gamma (IFNγ) levels and higher stem cell growth factor beta (SCGFβ) levels were associated with an increased risk of TAA (OR = 1.37, 95 % CI = 1.17-1.59, p = 7.42 × 10-5; OR = 1.43, 95 % CI = 1.19-1.74, p = 2.04 × 10-4; OR = 1.27, 95 % CI = 1.09-1.48, p = 2.40 × 10-3, respectively). In multivariable MR, the patterns of associations for the three cytokines remained adjusting for each other or smoking, but were attenuated differently with adjustment for other cardiovascular risk factors, especially for lipids and body mass index. Bidirectional MR approach did not identify any significant associations between cytokines and risk factors. Our results indicated that circulating cytokines may play mediation roles in the pathogenesis of TAA. Further studies are needed to determine whether these biomarkers can be used to prevent and treat TAA.

Association of Residential Greenness Exposure with Depression Incidence in Adults 50 Years of Age and Older: Findings from the Cohort Study on Global AGEing and Adult Health (SAGE) in China

BACKGROUND

Depression is a social and public health problem of great concern globally. Identifying and managing the factors influencing depression are crucial for preventing and decreasing the burden of depression.

OBJECTIVES

Our objectives are to explore the association between residential greenness and the incidence of depression in an older Chinese population and to calculate the disease burden of depression prevented by greenness exposure.

METHODS

This study was the Chinese part of the World Health Organization Study on Global AGEing and Adult Health (WHO SAGE). We collected the data of 8,481 residents ≥ 50 years of age in China for the period 2007-2018. Average follow-up duration was 7.00 (± 2.51 ) years. Each participant was matched to the yearly maximum normalized difference vegetation index (NDVI) at their residential address. Incidence of depression was assessed using the Composite International Diagnostic Interview (CIDI), self-reports of depression, and/or taking depression medication. Association between greenness and depression was examined using the time-dependent Cox regression model with stratified analysis by sex, age, urbanicity, annual family income, region, smoking, drinking, and household cooking fuels. Furthermore, the prevented fraction (PF) and attributable number (AN) of depression prevented by exposure to greenness were estimated.

RESULTS

Residential greenness was negatively associated with depression. Each interquartile range (IQR) increase in NDVI 500 -m buffer was associated with a 40% decrease [hazard ratio  ( HR ) = 0.60 ; 95% confidence interval (CI): 0.37, 0.97] in the risk of depression incidence among the total participants. Subgroup analyses showed negative associations in urban residents (HR = 0.32 ; 95% CI: 0.12, 0.86) vs. rural residents, in high-income residents (HR = 0.28 ; 95% CI: 0.11, 0.71) vs. low-income residents, and in southern China (HR = 0.50 ; 95% CI: 0.26, 0.95) vs. northern China. Over 8.0% (PF = 8.69 % ; 95% CI: 1.38%, 15.40%) and 1,955,199 (95% CI: 310,492; 3,464,909) new cases of depression may be avoided by increasing greenness exposures annually across China.

DISCUSSION

The findings suggest protective effects of residential greenness exposure on depression incidence in the older population, particularly among urban residents, high-income residents, and participants living in southern China. The construction of residential greenness should be included in community planning. https://doi.org/10.1289/EHP13947.

Unraveling the links between circulating bioactive factors and epilepsy: A bidirectional Mendelian randomization study

Epidemiological research has shown that a variety of circulating bioactive factors are associated with epilepsy, including macrophage colony-stimulating factor, interleukin-1β, and tumor necrosis factor-α. To further investigate the associations between epilepsy and 41 inflammatory cytokines, this Mendelian randomization was performed. This study presents genome-wide association study summary data on 41 inflammatory cytokines and epilepsy. Epilepsy incorporates generalized and focal epilepsy. A two-sample Mendelian randomization method was used. In order to analyze causal relationships between exposures and outcomes, the inverse variance-weighted method was mainly used. The findings suggested that increased levels of interleukin-1 receptor antagonists and interleukin-5 may be significantly associated with increased risks of focal epilepsy (beta: 0.080, P = .043; beta: 0.083, P = .015). In addition, regulated upon activation normal T cell expressed and secreted factor and Macrophage colony-stimulating factor may be significantly associated with generalized epilepsy (beta: 0.110, P = .042; beta: -0.114, P = .024). Furthermore, inflammatory cytokines such as interleukin-10, interleukin-1β, interleukin-1Ra, interleukin-7, tumor necrosis factor-α, and interferon-γ may be identified as the result of focal epilepsy (beta: 0.152, P = .031; beta: 0.214, P = .037; beta: 0.214, P = .047; beta: 0.222, P = .031; beta: 0.224, P = .025; beta: 0.161, P = .018). This study suggests that interleukin-5 and interleukin-1 receptor antagonists are potentially correlated factors with focal epilepsy etiology, macrophage colony-stimulating factor and regulated upon activation normal T cell expressed and secreted factor are potentially correlated factors with generalized epilepsy etiology, while several inflammatory cytokines possibly contribute to focal epilepsy development downstream.