Search results for "mediation analysis"
showing 10 items of 32 documents
Effects of Polycyclic Aromatic Hydrocarbons on Lung Function in Children with Asthma: A Mediation Analysis.
2022
Studies investigating the association between urinary Polycyclic Aromatic Hydrocarbons (PAHs) and asthma in children provided inhomogeneous results. We aimed to use Mediation Analysis to discover whether a link between urinary PAHs and lung function exists and if it might be ascribed to a direct or a symptom-mediated (indirect) effect in children with asthma. This single-center prospective study was conducted in Palermo, Italy, between March and July 2017 and involved 50 children with persistent mild-moderate asthma, aged 6–11 years. At each time visit (day 0, 30, 60, and 90), physical examination, spirometry, and urine collection for detection of urinary cotinine and PAHs were performed. A…
Analysing the mediating role of a network: a Bayesian latent space approach
2020
The use of network analysis for the investigation of social structures has recently seen a rise, due both to the high availability of data and to the numerous insights it can provide into different fields. Most analyses focus on the topological characteristics of networks and the estimation of relationships between the nodes. We adopt a different point of view, by considering the whole network as a random variable conveying the effect of an exposure on a response. This point of view represents a classical mediation setting, where the interest lies in the estimation of the indirect effect, that is, the effect propagated through the mediating variable. We introduce a latent space model mappin…
Go Cashless! Mobile Payment Apps Acceptance in Developing Countries: The Jordanian Context Perspective
2022
Despite the expanding global usage of mobile phones in money transactions, the adoption of mobile payment systems in Jordan remains slow. This study employed the technology acceptance model (TAM) to identify the factors with a potential impact on mobile payment systems acceptance. The impact of perceived privacy (PP) and the mediating function of perceived certainty (PC) on the behavioral intention (BI) of mobile payment systems among Jordanian ministries were examined. Data obtained from 270 respondents were analyzed using partial least-squares structural equation modeling (PLS-SEM). The empirical findings show a positive link between perceived usefulness (PU) and PC on the BI of mobile pa…
Effects of Difficulty in Handling Emotions and Social Interactions on Nomophobia: Examining the Mediating Role of Feelings of Loneliness
2022
Abstract This study was addressed to assess nomophobia in an Italian sample (N = 456, 53.1% men, Mage = 31.8, SD = 11.1), also providing a deeper knowledge about how it is distributed across demographics, as well as identifying its best predictors. The main goal was to investigate the direct and indirect effects of difficulty in emotion regulation and social interaction anxiety on nomophobia through loneliness. Our findings indicated that loneliness explained the effect of the expressive suppression strategy (fully) and social interaction anxiety (partially) on nomophobia, whereas it was not a significant mediator when the cognitive reappraisal strategy was taken into account. Our study sug…
Brain Cortical Complexity and Subcortical Morphometrics in Lifelong Premature Ejaculation
2020
Premature ejaculation (PE) is the most common male sexual dysfunction. The brain disturbances that cause this disorder remain poorly understood. This study aimed to investigate how the morphology of cortical and subcortical brain structures differed in PE, how these morphologic differences were associated with severity measures of PE, such as intravaginal ejaculatory latency time (IELT), and how these cortical and subcortical structures were causally connected through mediation analysis. Anatomical MRI scans were acquired from 39 male participants, 23 with PE (28.78 ± 4.32 years), and 16 without PE (27.88 ± 3.65 years). We used a subcortical analysis package within FSL to perform subcortica…
Does self-efficacy influence academic results? A separable-effect mediation analysis
2021
In causal mediation analysis, natural effects are identified only under strict assumptions involving cross-world counterfactuals. An alternative approach recently developed, called separable, allows for identification of mediational effects in a wide range of models, since it relies on weaker assumptions than those required by natural effects. In this paper, the separable-effect approach is revised and an application to data is presented.
Bayesian causal mediation analysis through linear mixed-effect models
2022
In mediational settings, the main focus is on the estimation of the indirect effect of an exposure on an outcome through a third variable called mediator. The traditional maximum likelihood estimation method presents several problems in the estimation of the standard error and the confidence interval of the indirect effect. In this paper, we propose a Bayesian approach to obtain the posterior distribution of the indirect effect through MCMC, in the context of mediational mixed models for longitudinal data. A simulation study shows that our method outperforms the traditional maximum likelihood approach in terms of bias and coverage rates.
Insights into the derivative-based method for nonlinear mediation models
2022
Associational mediation analysis has generally relied on the linearity of models to estimate the indirect effect as a product of regression coefficients. Very few examples of generalisations to nonlinear settings have been proposed, including a derivative-based method that, however, is far from being widely spread among scholars. In this paper, we clarify some aspects of such an approach to nonlinear mediation models, which have not been addressed by the previous literature. In addition, we run a simulation study to compare confidence intervals for the indirect effect obtained through different approaches.
Examining mediators of change in wellbeing, stress, and depression in a blended, Internet-based, ACT intervention for university students
2020
A coach-guided Acceptance and Commitment Therapy (ACT) intervention that uses a blended approach of two face-to-face and five online sessions (iACT; N = 33) has been found to be more effective than a waiting-list control condition (WLC; N = 35) at enhancing the wellbeing of university students while also reducing stress and depression. The present study explored possible mediators of change that may account for the outcomes of the study. Mediation analyses revealed that changes in the non-reactivity subscale of mindfulness mediated changes in wellbeing, depression, and stress in the iACT group. In addition, changes in the sense of coherence subscale of meaningfulness mediated changes in all…
Prenatal air pollution exposure and growth and cardio-metabolic risk in preschoolers
2020
Objectives: We investigated the association between outdoor air pollutants exposure in the first trimester of pregnancy, and growth and cardio-metabolic risk at four years of age, and evaluated the mediating role of birth weight. Methods: We included mother-child pairs (N = 1,724) from the Spanish INMA birth cohort established in 2003-2008. First trimester of pregnancy nitrogen dioxide (NO2) and fine particles (PM2.5) exposure levels were estimated. Height, weight, waist circumference, blood pressure, and lipids were measured at four years of age. Body mass index (BMI) trajectories from birth to four years were identified. Results: Increased PM2.5 exposure in the first trimester of pregnanc…