Bidirectional Links Research Articles

Cause or consequence? Exploring authors' interpretations of correlations between fish body condition and parasite infection.

We reviewed 194 publications that reported relationships between fish body condition indices (BCIs) and parasite infections, and examined the authors' intention behind this cross-sectional analysis, that is, whether authors interpreted the negative correlations as the negative effects of parasites or as fish with poor BCIs being more susceptible to infections. While 89% of studies only considered parasite infections as causes of poor BCI, studies acknowledging the opposite or bidirectional causal links were rare. We recommend considering both possibilities in any given fish host and parasite association.

Causal relationship between gut microbiota and malignant lymphoma: a two-way two-sample mendelian randomization study.

Emerging observational and clinical studies have highlighted the role of gut microbiota in hematologic malignancies, including malignant lymphoma. However, conflicting findings persist regarding the causal direction of this relationship, as traditional studies are susceptible to confounding factors and reverse causality. Mendelian randomization (MR) analysis, leveraging genetic variants as instrumental variables (IVs), offers a robust approach to infer causality by minimizing these biases. Here, we investigate the bidirectional causal links between gut microbiota and malignant lymphoma, addressing controversies in existing population-based studies. Bidirectional two-sample MR analysis was used to examine the causal relationship between malignant lymphoma and gut microbiota. The summary-level data of gut microbiota was obtained from the MiBioGen Consortium, a large-scale genome-wide study, involving 18,340 participants from a multiethnic cohort. Summary statistics for malignant lymphoma were sourced from the OpenGWAS website, which contains data from 490,803 participants. Using the standard quality-controlled single-nucleotide polymorphism (SNP) as an IV, we examined the potential causative link between gut microbiota and malignant lymphoma via the inverse variance weighting, MR Egger, weighted median, weighted model, and simple mode. Reverse MR analysis was further conducted on bacterial taxa identified as causally associated with malignant lymphoma in the forward MR analysis. Seven causal relationships between gut microbiota and malignant lymphoma were found, including the phylum Bacteroidetes [odds ratio (OR) =1.31; 95% confidence interval (CI): 1.02-1.68; P=0.03], the class Bacilli (OR =1.22; 95% CI: 1.00-1.49; P=0.048), the family Rikenellaceae (OR =1.27; 95% CI: 1.04-1.55; P=0.02), the genus Eubacterium nodatum group (OR =1.13; 95% CI: 1.00-1.27; P=0.046), the genus Oxalobacter (OR =1.23; 95% CI: 1.06-1.43; P=0.006), the genus Parabacteroides (OR =1.41; 95% CI: 1.00-1.99; P=0.049), and the genus Sellimonas (OR =1.18; 95% CI: 1.03-1.35; P=0.02). No significant level pleiotropy or heterogeneity was detected in the IV, and there was no reverse causality between gut microbiota and malignant lymphoma. We investigated the potential causal relationship between gut microbiota and malignant lymphoma. Our findings provide a theoretical foundation for future research on the relationship between gut microbiota and lymphoma, and may facilitate the development of diagnostic, therapeutic, and preventive strategies for lymphoma in clinical practice.

When the Smoke Will Not Clear: Examining the Longitudinal Effects of Political Despair on Well‐Being and Collective Climate Action

ABSTRACTAverting the existential risks that climate change poses requires sustained collective action, yet little is known about the factors that maintain versus undermine such commitment over time. This study tests whether participants' (N = 871) experience of political despair about climate change undermines long‐term collective climate action engagement both directly and indirectly because it diminishes well‐being (operationalised as stress, resilience and vitality). We examined these processes in the context of the 2019–2020 Australian black summer bushfires, measured across three time points (February, May and August 2020). Using a Random Intercept‐Cross Lagged Panel Model, we found significant trait‐level associations between political despair and well‐being, as well as political despair and collective climate actions. However, at the within‐person level, there was little support that political despair diminishes well‐being or intention to engage in collective climate action over time. Rather, results suggested the reverse: that feelings of political despair are outcomes of collective climate action and poor well‐being. This research highlights the importance of further examining the potentially dynamic and bidirectional links between emotions, action and well‐being.

Understanding Causal Relationships Between Imaging-Derived Phenotypes and Parkinson's Disease: A Mendelian Randomization and Observational Study.

Background/Objectives: Observational studies have suggested a correlation between brain imaging alterations and Parkinson's disease (PD). However, data on causal relationships are still lacking. This study aimed to examine the causal relationship between brain imaging-derived phenotypes (IDPs) and PD. Methods: A bidirectional two-sample Mendelian randomization analysis was conducted to explore the causal association between IDPs and PD. Summary-level data for IDPs (n = 39,691), PD (n = 482,730), and PD symptoms (n = 4093) were obtained from genome-wide association studies of European ancestry. Clinical validation was performed in an Asian cohort, which involved healthy controls (n = 81), patients with idiopathic rapid-eye-movement sleep behavior disorder (iRBD) (n = 47), and patients with PD (n = 85). Results: We found 13 IDPs with significant causal effects on PD and seven reciprocal effects of PD on IDPs. For instance, increased median T2star in the right caudate (odds ratio = 1.23, 95% confidence interval 1.08-1.40, p = 0.0057) and bilateral putamen (left: odds ratio = 1.25, 95% confidence interval 1.09-1.43, p = 0.0056; right: odds ratio = 1.25, 95% confidence interval 1.10-1.43, p = 0.0056) were associated with PD. Enlargement of the left thalamus (odds ratio = 1.50, 95% confidence interval 1.14-1.96, p = 0.016) demonstrated causal links with PD. No reverse causal effects were detected. Observational analyses results in the Asian cohort (healthy controls, iRBD, PD) aligned with the Mendelian randomization results. Conclusions: Our results suggest bidirectional causal links between IDPs and PD, offering insights into disease mechanisms and potential imaging biomarkers for PD.

Do child and household regulation moderate the bidirectional relation between harsh parenting and externalizing problems in the transition to adolescence?

The present study examined several distinct indicators of regulation (i.e., task-based executive function, surveyed child effortful control, and surveyed household chaos) as moderators of longitudinal bidirectional links between developmental changes in harsh parenting (HP) and child externalizing behaviors (EXT) from age 9 to 14 years. The sample included 311 children (50.4% female; 111 White or European American; 97 Hispanic or Latino; 103 Black or African American). We conducted cross-lagged panel analyses and utilized multiple reporters (mother, father, and child). Regarding bidirectionality between HP and EXT, findings were mixed depending on informant, but overall more child effects than parent effects or bidirectional effects emerged. Child and household regulation moderated certain effects, providing initial evidence of the potential role of regulations in bidirectional links between HP and EXT. The present study adds impetus to considering child self-regulation and household chaos as critical features influencing the bidirectional link between parenting and child functioning.

Bidirectional association between problematic smartphone use and aggressive behavior: Across-lagged longitudinal study.

Problematic smartphone use are prevalent worldwide, particularly among adolescents, and it is strongly linked with aggressive behavior. However, the understanding of how PSU may contribute to the emergence of aggressive behavior remains incomplete. The purpose of this study was to examine the bidirectional links between aggressive behavior and PSU among adolescents, utilizing data from a two-wave longitudinal study (the time interval is 15 months) conducted among 2,650 students in middle and high school. The cross-lagged models revealed that: (1)PSU at Time 1 (December 12) positively predicted aggressive behavior at Time 2 (March 2023, 15months apart) among older adolescents (15-19 years), but this was not the case for younger adolescents(11-14 years); (2) aggressive behavior at Time 1 positively predicted PSU at Time 2 for both younger and older adolescents. Our findings have identified PSU as a risk factor for aggressive behavior among older adolescents, with those perceiving higher PSU may be particularly vulnerable to developing aggressive behavior over time. These results not only enhance our understanding of the links between PSU and aggressive behavior but also provide significant theoretical perspectives for developing future prevention strategies and intervention measures to tackle aggressive behavior among adolescents.

Examining Bi-directional links between distinct affect states and tobacco lapse during a cessation attempt.

Examining Bi-directional links between distinct affect states and tobacco lapse during a cessation attempt.

Directional Temporal Relationship Between Hypertension and Non-Alcoholic Fatty Liver Disease: A Cross-Lagged Cohort Study.

The temporal relationship between non-alcoholic fatty liver disease (NAFLD) and hypertension (HTN) remains unclear despite their known association. Using data from the Beijing Health Management Cohort (BHMC) with a 5-year follow-up, we investigated these bidirectional links through Cox proportional hazards regression and a cross-lagged panel model (CLPM), adjusting for confounders. Systolic/diastolic blood pressure (SBP/DBP) and hepatic steatosis index (HSI) were treated as continuous variables to enhance biological interpretability. Cox regression revealed that HTN increased the risk of NAFLD (hazard ratio [HR]: 1.15, 95% confidence interval [CI]: 1.01-1.30, p <0.05) among participants without NAFLD at baseline, while NAFLD elevated the risk of HTN (HR: 1.11, 95% CI: 1.02-1.21, p <0.05) among those without HTN at baseline. However, CLPM involving 7349 participants identified a unidirectional temporal relationship from HTN to NAFLD, regression coefficients βSBP2017→HSI2022: 0.036 (95% CI: 0.012, 0.059), βDBP2017→HSI2022: -0.044 (95% CI: -0.068, -0.020), both p <0.05; but not from NAFLD to HTN, regression coefficients βHSI2017→SBP2022: 0.017 (95% CI: -0.003,0.037), βHSI2017→DBP2022:0.006 (95% CI: -0.016,0.028), both p >0.05. Overall, our study demonstrates a unidirectional temporal association from HTN to NAFLD. However, a bidirectional relationship was also observed in individuals under 60 years and in those without central obesity. These findings highlight the importance of considering age and central obesity to manage HTN to reduce the risk of future NAFLD and to manage NAFLD to reduce the risk of future HTN.

A longitudinal study of the bi-directional relations between parental bedtime and nighttime involvement and infant sleep.

A longitudinal study of the bi-directional relations between parental bedtime and nighttime involvement and infant sleep.

Revealing the Causal Relationship Between Differential White Blood Cell Counts and Depression: A Bidirectional Two-Sample Mendelian Randomization Study.

Background: The link between white blood cells (WBC) and depression has been studied, but the causal relationship remains unclear. This study aimed to elucidate the potential bidirectional causal links between six specific WBC count features and depression using a two-sample Mendelian randomization (MR) analysis, leveraging summary statistics from genome-wide association studies (GWAS). Method: The dataset on depression (N = 406,986) was sourced from the FinnGen database, while the dataset on WBC (N = 563,085) was obtained from a combined dataset of Blood Cell Consortium (BCX) and UK Biobank. The MR analyses employed include inverse variance weighted (IVW), MR-Egger, weighted median, contamination mixture method (conmix), and constrained maximum likelihood-based Mendelian randomization (cML-MA). A threshold p < 0.05 after false discovery rate (FDR) correction was set as the criterion for causality based on IVW. Results: Reverse MR analysis indicated a causal relationship where depression leads to an increase in overall WBC count (IVW beta = 0.031, p = 0.015, p FDR = 0.044) and specifically in basophil count (IVW beta = 0.038, p = 0.006, p FDR = 0.038), with a marginally significant impact on lymphocyte count (beta = 0.029, p = 0.036, p FDR = 0.071). Furthermore, forward MR analysis suggested a potential role of monocyte count in decreasing depression risk (p = 0.028), though this association did not retain statistical significance after FDR correction. Conclusion: These findings suggest that depression may causally influence the immune system by elevating overall WBC and basophil counts, with a marginally significant increase in lymphocyte levels. Conversely, higher monocyte count might confer some protection against depression, albeit with less statistial certainty. This study provides novel insights into the complex interplay between depression and immune function.

Grasping Posttraumatic Stress Disorder From the Perspective of Psychoneuroimmunoendocrinology: Etiopathogenic Mechanisms and Relevance for Integrative Management.

Grasping Posttraumatic Stress Disorder From the Perspective of Psychoneuroimmunoendocrinology: Etiopathogenic Mechanisms and Relevance for Integrative Management.

Towards Environmental Sustainability: Evaluating the Role of Energy Consumption, FDI, and Urbanization on Carbon Emission in Somalia: An Empirical Analysis using ARDL Bound Test

CO2 emissions stand for a global challenge due to their cross-border nature, contributing substantially to environmental degradation. Since the Industrial Revolution, affluent nations have accelerated economic growth, worsening this issue. However, this study examines the causal links between energy consumption, FDI, urbanization, and carbon emissions in Somalia from 1991 to 2020. The ARDL bounds test is used as a suitable method to estimate the long-run co-integration among the study's variables. The findings show that in the long run, energy consumption, FDI, and urbanization have a positive effect on CO2 emissions in Somalia. Additionally, economic growth contributes to carbon emissions, while trade openness helps reduce environmental pollution in the long run. Moreover, the study applied Granger causality to find out the directions of these relationships, revealing bidirectional causal links between economic growth and carbon emissions, and between urbanization and FDI. It also found unidirectional causality from carbon emissions to energy consumption, from FDI to carbon emissions, and from urbanization to CO2 emissions. The study recommended that Somali government must reconsider its energy policy to promote greener energy. Additionally, Somalia should increase investment in R&amp;D for energy efficiency and renewable energy to minimize the carbon emissions resulting from FDI.

Bidirectional links between sleep and pain among heavy-drinking Veterans with insomnia

Abstract Study Objectives Military veterans often suffer from chronic pain and sleep issues at a greater frequency than the general population, leading some to self-medicate with alcohol. While research shows a connection between sleep and pain, few studies have examined bidirectional links between sleep and pain at the daily level–or the extent to which alcohol use may moderate these associations. Methods Heavy-drinking veterans seeking treatment for insomnia (N=109, 82.5% male, mean age 38.9y) completed 14 days of morning diaries documenting sleep patterns, pain intensity, and alcohol consumption. Multilevel modeling examined within- and between-person associations between sleep (quality, duration, and efficiency) and next-day pain as well as pain and same-night sleep. Results Individuals with longer sleep duration, better sleep quality, and higher sleep efficiency reported lower pain levels compared to those with shorter sleep, poorer sleep quality, and lower sleep efficiency (p-values &amp;lt;.001 to .01). Additionally, on days when individuals experienced better sleep quality compared to their own average, they reported lower pain levels the following day (p=.01). In contrast to hypotheses, daily pain levels did not predict sleep outcomes at the daily within-person level, although significant between-person correlations were noted. Daily alcohol intake did not affect these relationships. Conclusions Sleep quality is associated with the daily experience of pain among heavy-drinking veterans with insomnia. Daily variations in sleep quality significantly impact pain, irrespective of alcohol consumption, highlighting a predominantly unidirectional influence from sleep to pain. These findings underscore the importance of optimizing sleep to mitigate pain in this population.

Feasibility of Polarization Division Multiplexing for Bidirectional Optical Links in 5G Radio over Fiber Cloud Access Networks

Objective: To investigate the potential of polarization division multiplexing in a 5G radio over fiber cloud access network to enable bidirectional optical links in the front-haul segment. Methodology: An optically centralized cloud radio access network based on polarization division multiplexing and radio-over-fiber transport is proposed. The exploitation of the polarization domain enables independent optical wavelength channels for the downlink and uplink. The experimental demonstration assesses the feasibility of the radio-over-fiber transport of information in a 5G-cloud radio access network. The demonstration evaluated the Error Vector Magnitude measurements for optical carrier linewidths of 0.1 nm. Data was experimentally measured for QPSK and 64QAM signals onto 3.5 GHz radio frequency across 10 km and 20 km of single mode optical fiber. Results: The experimental results evaluated the quality of the QPSK and 64QAM signals transported onto a polarization division multiplexing environment for an optically centralized transport in a 5G-cloud radio access network. 64QAM featured an EVM below 6% with a degradation of 2.8% and QPSK presented and EVM below 8% with a degradation of roughly 4.8% with respect to the back-to-back signal across a propagation length of 20 km. Conclusions: The results demonstrated that polarization multiplexing for an optically centralized transport in a 5G-cloud radio access network is feasible. Despite the relatively low optical power received in the uplink, the power penalties of the polarized components did not compromise the power budget so that optical amplification was not included in the measurements. Both QPSK and 64QAM fulfills the requirements of the 3GPP in terms of quality and signal integrity.

Testing the Mediational Role of Classroom Interactions in the Dynamic Interplay Between Teacher Emotional Exhaustion and Children’s Disruptive Behavior

ABSTRACT Research Findings: Teacher emotional exhaustion and classroom-level disruptive child behaviors are prominent risk factors influencing teacher and child social-emotional and behavioral outcomes. Additionally, theoretical perspectives position links between teacher emotional exhaustion and children’s disruptive classroom behavior as influenced by other proximally occurring teacher-child interactive processes. The purpose of the study is twofold: 1) examine longitudinal bi-directional relationships between teachers’ emotional exhaustion and children’s disruptive classroom behaviors, and 2) examine teachers’ classroom interactions (i.e. emotional support, instructional support, and classroom organization) as mediators of this potentially longitudinal bi-directional relationship. A total of 756 preschool-aged children and 101 preschool teachers across 17 schools serving children from primarily low-income families within the southeastern United States were examined. Data were collected through a multiple-methods approach. Multi-level path models examined the bi-directional associations between teachers’ emotional exhaustion and classroom-level child disruptive behaviors and the mediating role of teacher-facilitated classroom interactions. No bi-directional or mediational links were found; however, teachers’ emotional exhaustion was linked to children’s disruptive classroom behavior, and classroom disruptive behaviors were linked with teachers’ emotional support and classroom organization. Practice or Policy: Facilitating support for teachers’ well-being is critical for school personnel to continue to promote children’s classroom behaviors and maintain effective classroom interactions.

The real-world association between digital markers of circadian disruption and mental health risks

While circadian disruption is recognized as a potential driver of depression, its real-world impact is poorly understood. A critical step to addressing this is the noninvasive collection of physiological time-series data outside laboratory settings in large populations. Digital tools offer promise in this endeavor. Here, using wearable data, we first quantify the degrees of circadian disruption, both between different internal rhythms and between each internal rhythm and the sleep-wake cycle. Our analysis, based on over 50,000 days of data from over 800 first-year training physicians, reveals bidirectional links between digital markers of circadian disruption and mood both before and after they began shift work, while accounting for confounders such as demographic and geographic variables. We further validate this by finding clinically relevant changes in the 9-item Patient Health Questionnaire score. Our findings validate a scalable digital measure of circadian disruption that could serve as a marker for psychiatric intervention.

Assessment of bidirectional relationships between frailty and acute respiratory distress syndrome: a bidirectional Mendelian Randomization study

BackgroundWhile previous observational studies have suggested a link between frailty and acute respiratory distress syndrome (ARDS), the causality of this connection remains unclear. The objective of this study was to explore the potential bidirectional causal links between frailty and ARDS.MethodsA two-sample univariable Mendelian randomization (MR) was performed to assess the causal relationship between frailty, as defined by frailty index (FI, n = 175,226) and fried frailty score (FFS, n = 386,565), and ARDS. The genome-wide association study (GWAS) data of frailty was from the UK Biobank and the ARDS data was from the FinnGen Database. Univariable MR analyses were conducted using inverse-variance weighted (IVW), weighted median, MR-Egger regression, and robust adjusted profile score (MR. RAPS). We also performed multivariable Mendelian randomization (MVMR) analysis including smoking initiation, alcohol consumption, body mass index (BMI), and cognitive performance.ResultsThis bidirectional MR analysis demonstrated no causal effect of FI (OR = 0.96, 95% CI 0.14–6.88) and FFS (OR = 1.95, 95%CI 0.14–28.16) on increased susceptibility of ARDS. Also, no evidence was found for an effect of ARDS on the risk of frailty. The MVMR analysis indicated higher BMI and poorer cognitive performance were associated with increased risk of ARDS.ConclusionsThe outcomes of our analysis imply a probable absence of a direct causal relationship between frailty and susceptibility to ARDS. To reinforce and expand upon these preliminary findings, it is imperative to conduct larger-scale genome-wide association studies.

The association between sleep disturbance and nightmares: Temporal dynamics of nightmare occurrence and sleep architecture in the home.

We collected measures of sleep architecture and nightmares from participants (N = 61) wearing the DREEM 3 headband across 2 weeks of data collection to test the hypothesis that there are bidirectional links between insomnia (measured as sleep disturbance) and nightmare events. Nightmares were predicted by increased sleep disturbance the night before the nightmare, but not on the same night or 2 nights before. We also found that nightmare occurrences did not predict increased sleep disturbance on the same night or the following 2 nights, rather nightmares predicted increased sleep disturbance at the between-subjects level only. We suggest that nightmares are associated with an N3 sleep rebound on the night of the nightmare following a night of sleep disturbance.

Economic Integration and Economic Growth in ECOWAS Nations

The study explored the relationship between economic integration and economic growth in ECOWAS from 1986 to 2023. It utilized panel ARDL techniques, employing Pooled Mean Group (PMG) and Mean Group (MG) estimators, along with the Dumitrescu &amp; Hurlin Granger non-causality test. The findings revealed that economic integration positively correlates with economic growth in both the short and long term, although significance is only evident in the long run. In contrast, trade integration showed a positive but insignificant relationship with economic growth across both timeframes, while financial integration exhibited a negative and insignificant relationship with growth in both the short and long term. The causality test indicated that economic integration has a one-way causation toward economic growth; there are bidirectional causal links between trade integration and economic integration; a two-way causation exists between financial integration and economic integration; and there is a one-way causal relationship from trade integration to financial integration. Based on these findings, the study recommends that policymakers in ECOWAS prioritize the deepening and sustaining of economic integration initiatives, with a focus on enhancing regional cooperation in infrastructure, trade policies, and regulatory frameworks to achieve long-term growth benefits. To strengthen trade integration, ECOWAS countries should invest in export capacity, reduce bureaucratic hurdles, and support competitive industries while implementing trade facilitation and capacity- building programs. The negative impact of financial integration on growth underscores the need to bolster financial systems by improving regulatory oversight, advancing capital market development, and promoting financial stability through robust institutional frameworks. Moreover, it is essential to establish stronger regional institutions to monitor financial and trade flows and provide technical support for effectively managing and harmonizing integration processes.

Bidirectional Mendelian randomization links gut microbiota to primary biliary cholangitis

Primary biliary cholangitis (PBC) and gut microbiota (GM) are epidemiologically correlated but the causal inter-relationships remain poorly understood. We aim to explore the causal relationships between GM and PBC. Using the MiBioGen consortium, GWAS data for GM at the species level and the largest publicly available PBC GWAS data to date, we performed a bidirectional two-sample Mendelian randomization by the inverse variance weighted, MR-Egger, weighted median, weighted model and MR-PRESSO to elucidate the potential causal role of GM in PBC. To measure the heterogeneity of instrumental variables (IV), Cochran’s Q statistic and MR-Egger intercept test were used. Genetically instrumented order Coriobacteriales (odds ratio [OR] = 2.18, 95% confidence interval [CI] 1.30–3.66, P = 0.004) significantly increased the risk for PBC, while genetically driven class Deltaproteobacteria (OR = 0.52, 95% CI 0.36–0.74, P = 0.002) causally decrease the NAFLD risk. Reverse MR analysis showed no significant association between PBC and the two specific GM. However, it indicated that PBC progression significantly increases the abundance of the class Bacteroidia, order Bacteroidales, and phylum Bacteroidetes (OR = 1.02, 95% CI 1.002–1.03, P = 0.026), while decreasing the abundance of the genus Lachnospiraceae UCG010 (OR = 0.98, 95% CI 0.96–0.995, P = 0.026). Our study demonstrated that genetically driven order Coriobacteriales and class Deltaproteobacteria were causally related to PBC risk. This causality provided a new perspective on ameliorating PBC by modulating GM. Our study demonstrated that genetically driven order Coriobacteriales and class Deltaproteobacteria were causally related to PBC risk. PBC was causally related to the abundance of four GM taxa(class Bacteroidia, order Bacteroidales, phylum Bacteroidetes and genus Lachnospiraceae UCG010). This causality provided a new perspective on ameliorating PBC by modulating GM.