Browsing by Subject "mediation analysis"

Now showing 1 - 3 of 3
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    Mediators of improved PTSD symptoms in veterans and civilians following a yoga program
    (Cambridge University Press, 2023-08) Davis, Louanne W.; Schmid, Arlene A.; Daggy, Joanne K.; Yang, Ziyi; Biostatistics and Health Data Science, School of Medicine
    Objective: Although yoga shows some promise as an intervention for post-traumatic stress disorder (PTSD), little is known about how yoga reduces PTSD symptoms. The current study hypothesised that aspects of interoceptive awareness would mediate the effect of a yoga intervention on PTSD symptoms. Methods: We used data from our recently completed randomised controlled trial of a 16-week holistic yoga programme for veterans and civilians diagnosed with PTSD (n = 141) that offered weekly 90-minute sessions. We conducted a mediation analysis using interoceptive awareness and other variables that were associated with PTSD symptom reduction at mid-treatment and treatment end. Results: Although measures of anxiety, interoceptive awareness, and spirituality were identified in individual mediator models, they were no longer found to be significant mediators when examined jointly in multiple mediator models. When examining the multiple mediator models, the strongest mediator of the yoga intervention on PTSD symptoms was mental well-being at mid-treatment and stigma at the treatment end. The total effect of yoga on CAPS and PCL at the treatment end mediated by stigma was 37.1% (–1.81/–4.88) and 33.6% (–1.91/–5.68), respectively. Conclusion: Investigation of mental well-being and mental illness stigma as potential mediators is warranted in future studies of yoga as a treatment for PTSD as they may prove to be important foci for yoga interventions.
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    PNPLA3 rs738409 and Risk of Fibrosis in NAFLD: Exploring Mediation Pathways Through Intermediate Histological Features
    (Wiley, 2022) Vilar-Gomez, Eduardo; Pirola, Carlos J.; Sookoian, Silvia; Wilson, Laura A.; Liang, Tiebing; Chalasani, Naga; Medicine, School of Medicine
    Background & Aims It is unclear whether rs738409 (p.I148M) missense variant in patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 promotes fibrosis development by triggering specific fibrogenic pathways or by creating an unfavorable microenvironment by promoting steatosis, inflammation, and ultimately fibrosis. We tested the hypothesis that intermediate histologic traits, including steatosis, lobular and portal inflammation, and ballooning may determine the effect of rs738409 on liver fibrosis among individuals with biopsy-proven NAFLD. Approach and Results Causal mediation models including multiple mediators in parallel or sequentially were performed to examine the effect of rs738409, by decomposing its total effect on fibrosis severity into direct and indirect effects, mediated by histology traits in 1153 Non-Hispanic White (NHW) patients. Total effect of rs738409 on fibrosis was β=0.19 (95% CI: 0.09-0.29). The direct effect of rs738409 on fibrosis upon removing mediators' effects was β=0.09 (95% CI: 0.01-0.17) and the indirect effect of rs738409 on fibrosis through all mediators' effects were β=0.010 (95% CI: 0.04-0.15). Among all mediators, the greatest estimated effect size was displayed by portal inflammation (β=0.09, 95% CI: 0.05-0.12). Among different sequential combinations of histology traits, the path including lobular inflammation followed by ballooning degeneration displayed the most significant indirect effect (β=0.023, 95% CI: 0.011-0.037). Mediation analysis in a separate group of 404 individuals with biopsy-proven NAFLD from other races and ethnicity showed similar results. Conclusions In NAFLD, nearly half of the total effect of the rs738409 G allele on fibrosis severity could be explained by a direct pathway, suggesting that rs738409 may promote fibrosis development by activating specific fibrogenic pathways. A large proportion of the indirect effect of rs738409 on fibrosis severity is mediated through portal inflammation.
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    The Relationship between External Environment and Physician E-mail Communication: The Mediating Role of Health Information Technology (HIT) Availability
    (Lippincott Williams & Wilkins, 2015-11) Mazurenko, Olena; Hearld, Larry R.; Menachemi, Nir; Department of Health Policy and Management, School of Public Health
    Background: Physician e-mail communication, with patients and other providers, is one of the cornerstones of effective care coordination but varies significantly across physicians. A physician's external environment may contribute to such variations by enabling or constraining a physician's ability to adopt innovations such as health information technology (HIT) that can be used to support e-mail communication. Purpose: The aim of the study was to examine whether the relationship of the external environment and physician e-mail communication with patients and other providers is mediated by the practice's HIT availability. Methodology: The data were obtained from the Health Tracking Physician Survey (2008) and the Area Resource File (2008). Cross-sectional multivariable subgroup path analysis was used to investigate the mediating role of HIT availability across 2,850 U.S. physicians. Findings: Solo physicians' perceptions about malpractice were associated with 0.97 lower odds (p < .05) of e-mail communication with patients and other providers, as compared to group and hospital practices, even when mediated by HIT availability. Subgroup analyses indicated that different types of practices are responsive to the different dimensions of the external environment. Specifically, solo practitioners were more responsive to the availability of resources in their environment, with per capita income associated with lower likelihood of physician e-mail communication (OR = 0.99, p < .01). In contrast, physicians working in the group practices were more responsive to the complexity of their environment, with a physician's perception of practicing in environments with higher malpractice risks associated with greater information technology availability, which in turn was associated with a greater likelihood of communicating via e-mail with patients (OR = 1.02, p < .05) and other physicians (OR = 1.03, p < .001). Practical Applications: The association between physician e-mail communication and the external environment is mediated by the practice's HIT availability. Efforts to improve physician e-mail communication and HIT adoption may need to reflect the varied perceptions of different types of practices.