Genetically predicted elevated circulating 3,4-dihydroxybutyrate levels mediate the association between family Christensenellaceae and osteoporosis risk: a Mendelian randomization study.

Objective: To investigate the impact of gut microbiota on osteoporosis and identify the mediating role of blood metabolites in this process. Methods: This two-sample Mendelian randomization (MR) study utilized summary level data from genome-wide association studies (GWAS). Gut microbiota GWAS data were obtained from the MiBio-Gen consortium meta-analysis (n=13,266), while osteoporosis summary statistics were sourced from the FinnGen consortium R9 release data (7300 cases and 358,014 controls). Metabolite data, including 1400 metabolites or metabolite ratios, were derived from a study involving 8,299 unrelated individuals. The primary MR method employed was the inverse variance weighted (IVW) method. Reverse MR analysis was conducted on bacteria causally associated with osteoporosis in forward MR. The gut microbiota with the smallest p-value was selected as the top influencing factor for subsequent mediation analysis. A two-step MR approach quantified the proportion of the blood metabolite effect on gut microbiota influencing osteoporosis. IVW and Egger methods were used to assess heterogeneity and horizontal pleiotropy. Results: IVW estimates indicated a suggestive effect of family Christensenellaceae on osteoporosis (odds ratio(OR) = 1.292, 95% confidence interval(CI): 1.110-1.503, P =9.198 × 10-4). Reverse MR analysis revealed no significant causal effect of osteoporosis on family Christensenellaceae (OR = 0.947, 95% CI: 0.836-1.072, P =0.386). The proportion of the effect of family Christensenellaceae on osteoporosis mediated by circulating levels of 3,4-dihydroxybutyrate was 9.727%. No significant heterogeneity or horizontal pleiotropy was detected in the instrumental variables used for MR analysis. Conclusion: This study establishes a causal link between family Christensenellaceae and osteoporosis, with a minor proportion of the effect mediated by elevated circulating levels of 3,4-dihydroxybutyrate. Further randomized controlled trials (RCTs) are warranted to validate this conclusion.

Study approaches mediate associations between learning environment and academic performance.

BACKGROUND: While study approaches have been directly associated with students' academic performance, learning environment factors may play a more indirect role. The aim of this study was (i) to assess learning environment factors as predictors of students' average exam grades, and (ii) whether study approaches mediated associations between learning environment factors and exam grades. METHODS: Three annual surveys (2017-2019) yielded data from a total of 263 Norwegian occupational therapy students. Learning environment factors were assessed with the Course Experience Questionnaire, and the Approaches and Study Skills Inventory for Students were used to assess study approaches. Linear regression analyses and mediation analyses were performed. RESULTS: Higher levels of 'student autonomy' were directly associated with lower averaged grades whereas higher levels of 'appropriate workload' were associated with higher averaged grades. There were statistically significant total indirect effects of 'clear goals' and 'appropriate workload' on grades; these effects occurred through the study approach variables. However, all learning environment variables showed one or more relationships with academic performance that was mediated by study approach variables. CONCLUSION: Learning environment variables appear to be complexly associated with academic performance, both directly and indirectly.

Mediating effects of self-esteem and self-compassion on the relationship between body dissatisfaction and depression among adolescents with polycystic ovary syndrome.

Introduction: Body dissatisfaction significantly impacts depression among adolescents with polycystic ovary syndrome (PCOS). This relationship is compounded by various factors. Our study aims to explore the roles of self-esteem and self-compassion in the relationship between body dissatisfaction and depression in adolescent with PCOS. Methods: A cross-sectional study was conducted at the Shanghai First Maternity and Infant Hospital, involving 287 adolescents diagnosed with PCOS from January 2020 to December 2021. Participants completed validated questionnaires covering body dissatisfaction, self-esteem, self-compassion and depression. We utilized correlation and mediation analyses to examine the relationships and mediating effects among these variables. Results: Body dissatisfaction had a significant positive effect on depression (ß = 4.254, p < 0.001). Conversely, self-esteem (ß = -0.944, p < 0.001) and self-compassion (ß = -0.318, p < 0.001) were negative predictors of depression. Both self-esteem [ß = 3.405, 95% CI = (0.151, 0.305)] and self-compassion [ß = 1.525, 95% CI = (0.045, 0.165)] were shown to partially mediate the relationship between body dissatisfaction and depression, explaining 37.07% and 16.61% of the total effect, respectively. Conclusion: This study highlights the importance of fostering self-esteem and self-compassion among adolescents with PCOS to buffer the depressive effects of body dissatisfaction. Interventions aimed at promoting accurate and positive body perceptions, enhancing self-esteem, fostering a supportive attitude toward personal challenges, and maintaining positive emotional states are recommended to decrease the incidence of depression.

Exploring the Mediating Role of Multiple Organ Dysfunction in Sepsis-Induced Disseminated Intravascular Coagulation and Its Impact on Worsening Prognosis.

Disseminated intravascular coagulation (DIC) poses a high mortality risk, yet its exact impact remains contentious. This study investigates DIC's association with mortality in individuals with sepsis, emphasizing multiple organ function. Using data from the Peking University People's Hospital Investigation on Sepsis-Induced Coagulopathy database, we categorized patients into DIC and non-DIC groups based on DIC scores within 24 h of ICU admission (< 5 cutoff). ICU mortality was the main outcome. Initial data comparison preceded logistic regression analysis of mortality factors post-propensity score matching (PSM). Employing mediation analysis estimated direct and indirect associations. Of 549 participants, 131 were in the DIC group, with the remaining 418 in the non-DIC group. Following baseline characteristic presentation, PSM was conducted, revealing significantly higher nonplatelet sequential organ failure assessment (nonplt-SOFA) scores (6.3 ± 2.7 vs 5.0 ± 2.5, P < 0.001) and in-hospital mortality rates (47.3% vs 29.5%, P = 0.003) in the DIC group. A significant correlation between DIC and in-hospital mortality persisted (OR 2.15, 95% CI 1.29-3.59, P = 0.003), with nonplt-SOFA scores (OR 1.16, 95% CI 1.05-1.28, P = 0.004) and hemorrhage (OR 2.33, 95% CI 1.08-5.03, P = 0.032) as predictors. The overall effect size was 0.1786 (95% CI 0.0542-0.2886), comprising a direct effect size of 0.1423 (95% CI 0.0153-0.2551) and an indirect effect size of 0.0363 (95% CI 0.0034-0.0739), with approximately 20.3% of effects mediated. These findings underscore DIC's association with increased mortality risk in patients with sepsis, urging anticoagulation focus over bleeding management, with organ dysfunction assessment recommended for anticoagulant treatment efficacy.

Large-scale genetic correlation studies explore the causal relationship and potential mechanism between gut microbiota and COVID-19-associated risks.

Recent observational studies suggest that gut microorganisms are involved in the onset and development of coronavirus disease 2019 (COVID-19), but the potential causal relationship behind them remains unclear. Exposure data were derived from the MiBioGen consortium, encompassing 211 gut microbiota (n = 18,340). The outcome data were sourced from the COVID-19 host genetics initiative (round 7), including COVID-19 severity (n = 1,086,211), hospitalization (n = 2,095,324), and susceptibility (n = 2,597,856). First, a two-sample Mendelian randomization (TSMR) was performed to investigate the causal effect between gut microbiota and COVID-19 outcomes. Second, a two-step MR was used to explore the potential mediators and underlying mechanisms. Third, several sensitivity analyses were performed to verify the robustness of the results. Five gut microbes were found to have a potential causality with COVID-19 severity, namely Betaproteobacteria (beta = 0.096, p = 0.034), Christensenellaceae (beta = -0.092, p = 0.023), Adlercreutzia (beta = 0.072, p = 0.048), Coprococcus 1 (beta = 0.089, p = 0.032), Eisenbergiella (beta = 0.064, p = 0.024). Seven gut microbes were found to have a potential causality with COVID-19 hospitalization, namely Victivallaceae (beta = 0.037, p = 0.028), Actinomyces (beta = 0.047, p = 0.046), Coprococcus 2 (beta = -0.061, p = 0.031), Dorea (beta = 0.067, p = 0.016), Peptococcus (beta = -0.035, p = 0.049), Rikenellaceae RC9 gut group (beta = 0.034, p = 0.018), and Proteobacteria (beta = -0.069, p = 0.035). Two gut microbes were found to have a potential causality with COVID-19 susceptibility, namely Holdemanella (beta = -0.024, p = 0.023) and Lachnospiraceae FCS020 group (beta = 0.026, p = 0.027). Multi-omics mediation analyses indicate that numerous plasma proteins, metabolites, and immune factors are critical mediators linking gut microbiota with COVID-19 outcomes. Sensitivity analysis suggested no significant heterogeneity or pleiotropy. These findings revealed the causal correlation and potential mechanism between gut microbiota and COVID-19 outcomes, which may improve our understanding of the gut-lung axis in the etiology and pathology of COVID-19 in the future.

Clinical trials with mechanism evaluation of intervention(s): mind the power and sample size calculation.

BACKGROUND: Mediation analysis, often completed as secondary analysis to estimating the main treatment effect, investigates situations where an exposure may affect an outcome both directly and indirectly through intervening mediator variables. Although there has been much research on power in mediation analyses, most of this has focused on the power to detect indirect effects. Little consideration has been given to the extent to which the strength of the mediation pathways, i.e., the intervention-mediator path and the mediator-outcome path respectively, may affect the power to detect the total effect, which would correspond to the intention-to-treat effect in a randomized trial. METHODS: We conduct a simulation study to evaluate the relation between the mediation pathways and the power of testing the total treatment effect, i.e., the intention-to-treat effect. Consider a sample size that is computed based on the usual formula for testing the total effect in a two-arm trial. We generate data for a continuous mediator and a normal outcome using the conventional mediation models. We estimate the total effect using simple linear regression and evaluate the power of a two-sided test. We explore multiple data generating scenarios by varying the magnitude of the mediation paths whilst keeping the total effect constant. RESULTS: Simulations show the estimated total effect is unbiased across the considered scenarios as expected, but the mean of its standard error increases with the magnitude of the mediator-outcome path and the variability in the residual error of the mediator, respectively. Consequently, this affects the power of testing the total effect, which is always lower than planned when the mediator-outcome path is non-trivial and a naive sample size was employed. Analytical explanation confirms that the intervention-mediator path does not affect the power of testing the total effect but the mediator-outcome path. The usual effect size consideration can be adjusted to account for the magnitude of the mediator-outcome path and its residual error. CONCLUSIONS: The sample size calculation for studies with efficacy and mechanism evaluation should account for the mediator-outcome association or risk the power to detect the total effect/intention-to-treat effect being lower than planned.

Effect of spiritual intelligence and employment status on the association between education and depressive symptoms among adults in rural Puducherry, India: A mediation analysis.

BACKGROUND: Depression is a major global health concern, particularly in India, where it significantly impacts the population's well-being. The interplay of various factors, including education, employment status, and spiritual intelligence, contributes to the complex landscape of depressive symptoms among adults. METHODOLOGY: A community-based cross-sectional study was conducted in the rural service areas of a tertiary care medical institution in rural India from March 2021 to September 2022. The study employed structured questionnaires and validated scales to assess depressive symptoms, spiritual intelligence, educational status, and occupational status among participants. Structural equation modelling was used for mediation analysis to evaluate the effect of spiritual intelligence and employment status on the association between education and depressive symptoms. RESULTS: The study included 381 participants, with a prevalence of depressive symptoms at 14.4%. Higher educational attainment was associated with lower odds of depressive symptoms (aOR = 0.34, 95% CI [0.17, 0.67]). Employment status mediated the relationship between education and depression, with employed individuals exhibiting lower odds of depressive symptoms (aOR = 0.42, 95% CI [0.22, 0.82]). While spiritual intelligence was higher among those with formal education, its direct impact on depression was not statistically significant. The mediation analysis revealed that a significant portion (77.5%) of the total effect of education on depression was mediated through employment status and spiritual intelligence. CONCLUSION: The study underscores the importance of education and employment opportunities in mitigating depressive symptoms among rural adults. It suggests targeted interventions that promote education and employment support to enhance mental health resilience. While spiritual intelligence may influence mental health outcomes, its exact role requires further investigation.

Polygenic Risk and Coronary Artery Disease Severity.

BACKGROUND: Coronary atherosclerotic burden and adverse coronary heart disease events are related phenotypes with likely shared genetic cause. METHODS: We analyzed 6021 patients with available coronary angiography, genotyping, and exome sequencing data. We tested for associations of polygenic risk scores for coronary heart disease (PRSCHD) with multiple measures of coronary artery disease (CAD) severity. We assessed the interplay between PRSCHD and pathogenic/likely pathogenic variants in 3 familial hypercholesterolemia genes. We performed mediation analyses to explore whether CAD severity mediated the association of PRSCHD with prevalent coronary heart disease and incident myocardial infarction. RESULTS: A 1-SD increase in PRSCHD was associated with multiple measures of CAD severity, including the log Gensini score (ß, 0.31 [95% CI, 0.28-0.33]). Carrying a pathogenic/likely pathogenic familial hypercholesterolemia variant was associated with a higher log Gensini score after adjustment for PRSCHD (ß, 0.21 [95% CI, 0.03-0.38]). PRSCHD was associated with incident myocardial infarction over a mean follow-up of 9.2 years (hazard ratio, 1.20 [95% CI, 1.13-1.27]; P=5×10-10), and the Gensini score mediated 90% of this association. CONCLUSIONS: PRSCHD was associated with multiple measures of CAD severity. The association of PRSCHD with incident myocardial infarction was almost fully mediated by CAD severity, indicating a considerable genetic overlap between the 2 phenotypes.

Leisure television watching exerts a causal effect on gastroesophageal reflux disease: evidence from a two-step mendelian randomization study.

BACKGROUND: Previous studies have shown that physical activity (PA) and leisure sedentary behaviors (LSB, including leisure television watching) are linked to gastroesophageal reflux disease (GERD). However, the associations between PA/LSB and GERD remain controversial. In this study, we aimed to reveal whether these associations reflect causal relationships and reveal the potential mechanisms of these relationships using bidirectional and two-step Mendelian randomization (MR) analyses. METHODS: We obtained genome-wide association study (GWAS) summary statistics for PA/LSB, four common risk factors (including cigarettes smoked per day, alcoholic drinks per week, triglycerides, total cholesterol) and GERD from published GWASs. A bidirectional MR analysis was performed to identify causal relationships between PA/LSB and GERD. Then, a series of sensitivity analyses were performed to verify the robustness of the results. Finally, a mediation analysis via two-step MR was conducted to investigate any effects explained by common risk factors in these relationships. RESULTS: Genetically predicted per 1-SD increase in leisure time television watching significantly increased the risk of GERD in the bidirectional MR analysis (OR = 1.33; 95% CI: 1.14-1.56; P = 2.71 × 10- 4). Sensitivity analyses successfully verified the robustness of the causal relationship. Further mediation analysis showed that this effect was partly mediated by increasing cigarettes smoked per day, with mediated proportions of 18.37% (95% CI: 11.94-39.79%). CONCLUSION: Our findings revealed a causal relationship between leisure television watching and an increased risk of GERD, notably, the causal effect was partially mediated by cigarettes smoked per day. These findings may inform prevention and management strategies directed toward GERD.

Associations of remnant cholesterol in early pregnancy with gestational diabetes mellitus risk: a prospective birth cohort study.

BACKGROUND: Remnant cholesterol (RC) reportedly contributes to the development of diabetes mellitus. However, evidence on the relationship between maternal RC and the risk of developing gestational diabetes mellitus (GDM) during pregnancy is limited. This study aimed to assess the relationship between maternal RC and GDM risk during early pregnancy, and explore the potential pathways involved in the relationship between RC levels and GDM risk. METHODS: From 2018 to 2021, a prospective birth cohort study was designed and carried out in China. The associations of maternal RC and other lipid parameters with GDM risk were estimated using logistic regression models and restricted cubic splines. Subgroup analyses were performed stratified by prepregnancy body mass index (pre-BMI), maternal age and gravidity. Mediation analyses were conducted to explore the mediating effect of some related factors on the relationship between RC levels and the risk of GDM. RESULTS: A total of 33,018 pregnant women were included. The median RC level was 0.47 ± 0.20 mmol/L. The prevalence of GDM was 15.19%. As RC quartiles increased, the incidence of GDM increased substantially, reaching 19.24% for the highest quartile of RC (P < 0.001). Maternal RC in the first trimester was positively correlated with GDM risk (OR: 2.254, 95% CI: 1.943-2.615). Compared to the lowest RC quartile, higher RC quartiles were correlated with an increased risk of GDM, and the ORs (95% CIs) for Q3 and Q4 were 1.208 (1.101-1.325) and 1.489 (1.364-1.626), respectively. Moreover, a linear dose-response relationship was found for this association (P for all < 0.001, P for nonlinearity > 0.05) and was consistent across subgroups with different pre-BMIs, maternal ages and gravidities (all P values for interactions > 0.05). Furthermore, the correlation between RC level and GDM risk was partially mediated by pre-BMI (9.20%) and blood glucose level (-11.1%). CONCLUSIONS: Higher maternal RC levels in the early stage of pregnancy was positively associated with an increased risk of developing GDM. This association was partially mediated by pre- BMI and blood glucose levels.

Association of serum 25-hydroxyvitamin D with stroke: Observational mediation and Mendelian Randomization Study.

CONTEXT: The causal association and biological mechanism linking serum 25-hydroxyvitamin D to stroke risk lacks epidemiological evidence. OBJECTIVE: This study aimed to investigate the association between 25(OH)D concentration and stroke risk as well as the potential mediating factors. DESIGN: The community-based prospective community-based cohort study, the Chin-Shan Community Cardiovascular Cohort, was conducted from 1990 to December 2011, with external validation using a two-sample Mendelian randomization (MR) study. PATIENTS: A total of 1,778 participants with serum 25-hydroxyvitamin D data were enrolled. METHODS: In the CCCC observational study, the outcome was ascertained as stroke, while in the two-sample MR study, it was defined as ischemic stroke. Causal effects were estimated using restricted cubic spline analysis, COX proportional hazard ratios, mediation analysis, and two-sample MR. RESULTS: Over 12 years (21,598 person-years) of follow-up, 163 participants (9.17%) developed stroke. Higher 25(OH)D concentrations were associated with lower stroke risk (hazard ratio: 0.64; 95% confidence interval, 0.43-0.96) after full-model adjustments. Mediation analysis showed a significant association between 25(OH)D concentration and stroke risk mediated by hypertension in unadjusted models (mediation percentage 23.3%, p=0.008) that became non-significant in full models (mediation percentage, 15.5%; p=0.072). Two-sample MR confirmed a significant inverse association between genetically determined 25(OH)D and stroke risk (IVW OR: 0.92; 95% CI: 0.85-0.99; p=0.036). However, hypertension had an insignificant mediating role in the Mendelian randomization study. CONCLUSIONS: Higher 25(OH)D levels are linked to reduced stroke risk, potentially mediated by hypertension. Prioritizing blood pressure management may improve stroke prevention in 25(OH)D-deficient patients.

Mediation analysis for TNF-α as a mediator between multiple metal exposure and kidney function.

The association between metal mixtures and kidney function has been reported. However, reports on the mechanism of metal toxicity were limited. Oxidative stress was reported as a possible cause. This study aimed to determine the association between of kidney function and metals, such as arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), selenium (Se), and zinc (Zn), and to explore the possible mediating role of tumor necrosis factor alpha (TNF-α) between metal toxicity and kidney function. In this study, we recruited 421 adults from a health examination. The concentration of blood metals was analyzed using inductively coupled plasma mass spectrometry. We used linear regression models to assess the association between metals and TNF-α. Then, mediation analysis was applied to investigate the relationship between metal exposure, TNF-α, and kidney function. In univariate linear regression, blood As, Cd, Co, Cu, Pb, and Zn levels significantly increased TNF-α and decreased kidney function. Higher blood As and Pb levels significantly increased TNF-α in multivariable linear regressions after adjusting for covariates. We found that blood levels of As (coefficients = -0.021, p = 0.011), Pb (coefficients = -0.060, p < 0.001), and Zn (coefficients = -0.230, p < 0.001) showed a significant negative association with eGFR in the multiple-metal model. Furthermore, mediation analysis showed that TNF-α mediated 41.7 %, 38.8 %, and 20.8 % of blood Cd, As and Pb, respectively. Among the essential elements, TNF-α mediated 24.5 %, 21.5 % and 19.9 % in the effects of blood Co, Cu, and Zn on kidney function, respectively. TNF-α, acting as a mediator, accounted for 20.1 % of the contribution between the WQS score of metal mixtures and the eGFR (p < 0.001). This study suggested that TNF-α may be a persuasive pathway mediating the association between metals and kidney function. Inflammation and kidney injury could be the underlying mechanisms of metal exposure. However, there is still a need to clarify the biochemical mechanism in follow-up studies.

Multiple mediation analysis of a task-shared psychosocial intervention for perinatal anxiety: Exploratory findings from a randomized controlled trial in Pakistan.

BACKGROUND: The "Healthy Mother Healthy Baby" (HMHB) study is a phase three, single-blind randomized clinical trial conducted at Holy Family Hospital (HFH) in association with Rawalpindi Medical University (RMU). We aimed to examine the mediators of a specialized psychosocial approach based on Cognitive Behavioural Therapy principles, targeting pregnant women experiencing anxiety. The HMHB intervention was effective in treating perinatal anxiety symptoms and preventing future depressive episodes. METHODS: The trial randomized participants into two arms: the HMHB intervention or Enhanced Usual Care (EUC), following World Health Organization guidelines. The HMHB intervention comprised strategies to strengthen social support networks, improving mother-baby bonding and strategies to deal with interpersonal conflicts, economic challenges, and societal gender preferences using cognitive and behavioural techniques and culturally resonant illustrations. Participants underwent rigorous data collection at three pivotal timepoints: baseline, third trimester, and 6-weeks postnatal. The primary outcome was anxiety symptom severity scores using the Hospital Anxiety and Depression Scale (HADS) at 6-weeks post-childbirth. Four potential mediators - social support, behavioural activation, perceived stress, and pregnancy experience - were assessed in the third trimester of pregnancy. RESULTS: A total of 1200 participants were randomized to the HMHB and EUC arms. In the six-week follow-up time point, 379 participants remained in the EUC group, and 387 continued in the HMHB group. Post-intervention, HMHB participants displayed significant improvements in postnatal anxiety and depression scores. Mediation analyses revealed social support and pregnancy hassles as significant mediators of the intervention's effect on postnatal anxiety outcomes, while only social support emerged as a significant mediator for depression outcomes. CONCLUSION: The HMHB intervention showed promising results in improving anxiety and depression scores among pregnant women. Significant mediation effects suggest the importance of targeting social support and managing pregnancy-related hassles for optimal intervention effectiveness.

Decomposition analysis to assess intervention strategies for reducing health-related exposure disparities in Michigan public drinking water systems.

OBJECTIVE: Contamination in U.S. public drinking water systems (PWS) is estimated to cause millions of illnesses and billions of dollars in medical expenditures annually. Few prior studies have explored intervention strategies, including environmental enforcement, to reduce estimated health-related exposure disparities (exposure disparity) in PWS, which are driven partially by socioeconomic status (SES), racism, and PWS characteristics. METHOD: This study used a longitudinal measurement method to estimate the annual health-related exposure level (health level) of each PWS in Michigan, based on data from the Enforcement and Compliance Online (ECHO) and U.S. Census Bureau databases. Using a decomposition model with four strategies, we analyzed how eliminating disparities in SES, proportion minority, environmental enforcement, and PWS characteristics across communities would affect adjusted exposure disparities. RESULTS: This study found that adjusted race- and poverty-based exposure disparities have existed since the 1980s but might have decreased in the last one or two decades. PWS characteristics strongly impacted the crude and adjusted exposure disparity. Environmental enforcement, although less effective in minority-concentrated communities, reduced the adjusted race-based exposure disparity by 10%-20% in the 1980s, 8% in the 1990s, and 0.012% in the 2010s. Equalizing the poverty rate distribution reduced the adjusted race-based exposure disparity by 0.72% in the 1980s and 6.8% in the 2010s. However, equalizing racial and ethnic composition distribution increased the adjusted poverty-based exposure disparity in the 2000s. CONCLUSION: These findings indicate that economically disadvantaged or minority-concentrated communities in Michigan disproportionately suffer from poorer PWS quality. Enhanced environmental enforcement, increased household income, PWS investment, and other actions are needed to address these exposure disparities effectively.

Path-specific causal decomposition analysis with multiple correlated mediator variables.

A causal decomposition analysis allows researchers to determine whether the difference in a health outcome between two groups can be attributed to a difference in each group's distribution of one or more modifiable mediator variables. With this knowledge, researchers and policymakers can focus on designing interventions that target these mediator variables. Existing methods for causal decomposition analysis either focus on one mediator variable or assume that each mediator variable is conditionally independent given the group label and the mediator-outcome confounders. In this article, we propose a flexible causal decomposition analysis method that can accommodate multiple correlated and interacting mediator variables, which are frequently seen in studies of health behaviors and studies of environmental pollutants. We extend a Monte Carlo-based causal decomposition analysis method to this setting by using a multivariate mediator model that can accommodate any combination of binary and continuous mediator variables. Furthermore, we state the causal assumptions needed to identify both joint and path-specific decomposition effects through each mediator variable. To illustrate the reduction in bias and confidence interval width of the decomposition effects under our proposed method, we perform a simulation study. We also apply our approach to examine whether differences in smoking status and dietary inflammation score explain any of the Black-White differences in incident diabetes using data from a national cohort study.

Causal mediation analyses for the natural course of hepatitis C: a prospective cohort study.

BackgroundHepatitis C virus (HCV) infection is a systemic disease. However, the relative contribution of intrahepatic and extrahepatic diseases to mediating HCV-induced mortality is unclear, albeit critical in resource allocation for reducing preventable deaths. To this end, this study comprehensively quantified the extent to which intrahepatic and extrahepatic diseases mediate HCV-induced mortality.MethodsA community-based cohort study with >25 years of follow-up was conducted in Taiwan. HCV infection was profiled by antibodies against HCV and HCV RNA in participants' serum samples. The cohort data were linked to Taiwan's National Health Insurance Research Database to determine the incidences of potential mediating diseases and mortality. We employed causal mediation analyses to estimate the mediation effects of HCV on mortality in relation to the incidences of 34 candidate diseases.ResultsIn 18,972 participants with 934 HCV infection, we observed that 54.1% of HCV-induced mortality was mediated by intrahepatic diseases, such as liver cirrhosis and liver cancer, and 45.9% of mortality was mediated by extrahepatic diseases. The major extrahepatic mediating diseases included septicemia (estimated proportion of HCV-induced mortality mediated through the disease: 25.2%), renal disease (16.7%), blood/immune diseases (12.2%), gallbladder diseases (9.7%), and endocrine diseases (9.6%). In women, hypertension (20.0%), metabolic syndrome (18.9%), and type 2 diabetes (17.0%) also mediated HCV-induced mortality. A dose-response relationship of HCV viral load was further demonstrated for the mediation effect.ConclusionBoth intrahepatic and extrahepatic manifestations mediated approximately a half of HCV-induced mortality. The mediation mechanisms are supported by a dose-response relationship of HCV viral load.

Elevated maternal serum bile acids Level, hypertensive disorders of pregnancy and adverse fetal Outcomes: A cohort study of 117,789 pregnant women in China.

BACKGROUND: Elevated maternal serum total bile acids (sTBA) level during pregnancy was associated with adverse fetal outcomes. Women with elevated sTBA could complicate with hepatic dysfunction or vascular disorders (hypertensive disorders of pregnancy, HDP), which aggravated adverse fetal outcomes. However, the relationships among sTBA level, hepatic dysfunction, HDP and adverse fetal outcomes were still illusive. OBJECTIVE: We aimed to explore whether hepatic dysfunction or vascular disorders (HDP) mediated the associations between elevated sTBA level and adverse fetal outcomes. METHODS: A large retrospective cohort study encompassing 117,789 Chinese pregnant women with singleton delivery between Jan 2014 and Dec 2022 was conducted. Causal mediation analysis was applied to assess the mediating role of hepatic dysfunction (alanine transaminase > 40 U/L) or HDP in explaining the relationship between high maternal sTBA level (≥10 µmol/L) and adverse fetal outcomes, including low birth weight (LBW), small for gestational age (SGA), and preterm birth (PTB). RESULTS: sTBA level were positively associated with LBW (adjusted odds ratio (aOR) = 1.40; [95 % confidence interval (CI): 1.24-1.59]), SGA (aOR=1.31; [95 % CI: 1.18-1.46]), and PTB (aOR=1.27; [95 % CI: 1.15-1.41]), respectively. The estimated proportions of the total associations mediated by HDP were 47 % [95 % CI: 31 %-63 %] for LBW, 24 % [95 % CI: 13 %-35 %] for SGA, and 34 % [95 % CI: 19 %-49 %] for PTB, excepting the direct effects of high sTBA level. The contribution of hepatic dysfunction as a mediator was weaker on the association between high sTBA level on fetal outcomes, as the proportions mediated and 95 % CI were 16 % [4 %-29 %], 4 % [-6%-14 %], 32 % [15 %-50 %] for LBW, SGA, and PTB, respectively. Moreover, the mediating effect of hepatic dysfunction was nearly eliminated after excluding cases of HDP in the sensitivity analysis. CONCLUSIONS: The substantial mediating effects through HDP highlighted its significant role in adverse fetal outcomes associated with elevated sTBA level. The findings also provoked new insights into understanding the mechanism and developing clinical management strategies (i.e. vascular protection) for adverse fetal outcomes associated with elevated sTBA level.

Exploring the mediating role of the ventral attention network and somatosensory motor network in the association between childhood trauma and depressive symptoms in major depressive disorders.

BACKGROUND: Childhood trauma is closely tied to adult depression, but the neurobiological mechanisms remain unclear. Previous studies suggested associations between depression and large-scale brain networks such as the Ventral Attention Network (VAN) and Somatosensory Motor Network (SMN). This study hypothesized that functional connectivity (FC) within and between these networks mediates the link between childhood trauma and adult depression. METHODS: The Childhood Trauma Questionnaire (CTQ) assessed developmental experiences, and the Hamilton Rating Scale for Depression (HAMD-17) gauged depressive symptoms. Resting-state functional magnetic resonance imaging (fMRI) analyzed FC within and between the VAN and SMN. RESULTS: Depression group exhibited significantly higher HAMD and CTQ scores, as well as elevated FC within the VAN and between the VAN and SMN (P < 0.05). Positive correlations were found between HAMD total score and FC within the VAN (P < 0.05, r = 0.35) and between the VAN and SMN (P < 0.05, r = 0.34), as well as with CTQ total score (P < 0.05, r = 0.27). Positive correlations were also observed between CTQ total score and FC within the VAN (P < 0.05, r = 0.31) and between the VAN and SMN (P < 0.05, r = 0.29). In the mediation model, FC within and between the VAN and SMN significantly mediated childhood trauma and depression. LIMITATIONS: The cross-sectional design limits causal inference. The sample size for different trauma types is relatively small, urging caution in generalizing findings. CONCLUSIONS: The study underscores the association between depression severity, VAN dysfunction, abnormal VAN-SMN FC, and childhood trauma. These findings contribute to understanding the neurobiological mechanisms underlying childhood trauma and depression.

The relationship between growth mindset and cognitive fusion in college students is mediated by bias towards negative information.

This study aimed to investigate the relationships among growth mindset, cognitive fusion, bias towards negative information, and bias towards positive information. The Growth Mindset Scale, the Attention to Positive and Negative Information Scale, and the Cognitive Fusion Questionnaire were employed. A total of 470 college students in China participated in the study. The findings showed a negative correlation between a growth mindset and cognitive fusion. In addition, a parallel mediation analysis demonstrated that bias towards negative information mediated the relationship between a growth mindset and cognitive fusion and that the indirect effect was significant. However, the mediation of bias towards positive information in this model was not significant. These results suggest that possessing a growth mindset is advantageous for mental health.