Browsing by Subject "Mediation"

Now showing 1 - 5 of 5
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    Delay in sexual maturation in perinatally HIV-infected youths is mediated by poor growth
    (Lippincott, Williams & Wilkins, 2017-06-01) Bellavia, Andrea; Williams, Paige L.; DiMeglio, Linda A.; Hazra, Rohan; Abzug, Mark J.; Patel, Kunjal; Jacobson, Denise L.; Van Dyke, Russell B.; Geffner, Mitchell E.; International Maternal Pediatric and Adolescent AIDS Clinical Trials (IMPAACT) P219/219C Study; Pediatric HIV/AIDS Cohort Study (PHACS); Pediatrics, School of Medicine
    OBJECTIVE: To evaluate the association between HIV infection and sexual maturation, and mediation of this association by HIV effects on growth. DESIGN: Pooled data were analyzed from two longitudinal cohort studies, the International Maternal Pediatric Adolescent AIDS Clinical Trials P219/219C Study (1993-2007) and the Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol (2007-2015), including perinatally HIV-infected (PHIV) and HIV-exposed uninfected (PHEU) youths. METHODS: We evaluated age at sexual maturity among 2539 PHIV and PHEU adolescents based on annual physician-assessed pubertal staging measures. Interval-censored regression models were used to evaluate associations of HIV infection with age at maturity. Mediation analyses accounting for height and BMI Z-scores at specific ages were used to estimate direct and indirect effects of HIV infection on age at sexual maturity. RESULTS: Mean ages at sexual maturity for PHIV girls (n = 1032) were 15.5 years for both female breast and pubic hair and 15.9 and 15.8 years for PHIV boys (n = 1054) for genitalia and pubic hair, respectively. PHIV youths matured approximately 6 months later on average than PHEU (n = 221 girls and 232 boys), and this difference persisted after adjustment for race/ethnicity and birth cohort. BMI and height Z-scores mediated the association between HIV infection and later maturation in girls, accounting for up to 74% of the total HIV effect. Only height Z-scores mediated the effect of HIV on male age at maturity, accounting for up to 98% of the HIV effect. CONCLUSION: PHIV youths attain sexual maturity later on average than PHEU youths. Much of this difference may be attributable to deficient growth, suggesting directions for future interventions.
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    Examining psychological inflexibility as a mediator of postpartum depressive symptoms: A longitudinal observational study of perinatal depression
    (Elsevier, 2023) Thomas, Emily B. K.; Miller, Michelle L.; Grekin, Rebecca; O’Hara, Michael W.; Psychiatry, School of Medicine
    Background: Depression is a common, serious complication during the postpartum period. Predictors of postpartum depression characterize who is at-risk for persistent symptoms. This study explored how psychological inflexibility affects depressive symptoms at 4 and 12 weeks postpartum. Methods: Participants receiving prenatal care at a medical center were recruited during the second trimester. Participants (n = 180) completed online assessments and diagnostic interviews during the third trimester (≥ 28 weeks gestation), and at 4-, 8-, and 12-weeks postpartum. Online assessments measured psychological inflexibility (PI) and depressive symptoms, while diagnostic interviews measured lifetime history of depression. Results: Mediation analysis examined pathways between 4-weeks postpartum depression, 8-weeks postpartum PI, and 12-weeks postpartum depression. Depressive symptoms at 4-weeks postpartum predicted PI at 8-weeks postpartum (β = 0.31, SE = 0.06, t(177) = 6.06, p < .001). Depressive symptoms at 4-weeks postpartum (β = 0.42, SE = 0.06, t(176) = 7.12, p < .001) and PI at 8-weeks postpartum (β = 0.32, SE = .08, t(176) = 4.09, p < .001) predicted depressive symptoms at 12-weeks postpartum. Depressive symptoms at 4-weeks, 8-week PI, and lifetime history of depression accounted for 42% of the variance in 12-week depressive symptoms (R2 = 0.42). The confidence interval of the indirect effect (0.04, 0.18) did not include zero, indicating significant mediation by PI. Conclusions: PI mediated the relation between 4- and 12-weeks postpartum depressive symptoms when controlling for lifetime history of depression. Psychological inflexibility is a transdiagnostic target for future prevention and intervention research during the postpartum period.
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    Examining the feedback environment and accountability in informal performance management systems
    (2013-03-06) Coulter-Kern, Paige E.; Williams, Jane R.; Ashburn-Nardo, Leslie; Boyd, Elizabeth; Grahame, Nicholas J.
    Improving performance management is a high priority for many organizations that want to improve the performance of their employees. Recently, researchers have focused on the social context to promote behavioral change, and have created new scales to examine context, such as the feedback environment. The current study examined internal and external accountability as mediators of the relationship between the feedback environment and developmental behaviors. Participants each completed three scales measuring the feedback environment, internal and external accountability, and developmental behaviors. Results suggested that internal and external accountability both mediate the relationship between the feedback environment and developmental behaviors, but neither is a stronger mediator than the other. In addition, internal and external accountability both mediate the relationship between each component of the feedback environment and developmental behaviors, but again neither is a stronger mediator than the other. This study contributed to the literature on performance management, and emphasized the importance of training supervisors to use the feedback environment to increase perceptions of accountability for employees.
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    An Experimental Investigation and Conditional Process Analysis of the Role of Catastrophizing in the Pain — Working Memory Nexus
    (2019-12) Procento, Philip Matthew; Hirsh, Adam T.; Stewart, Jesse C.; Rand, Kevin L.
    There is a well-documented bidirectional relationship between pain and cognitive dysfunction, especially working memory. Despite this extensive body of research, the pain–working memory relationship is poorly understood. Pain catastrophizing – exaggerated negative cognitive and emotional responses towards pain – may contribute to working memory deficits by occupying finite, shared cognitive resources, but this has yet to be investigated. The present study sought to clarify the role of pain catastrophizing (assessed as both a trait-level disposition and state-level process) in working memory dysfunction. Healthy undergraduate participants were randomized to an ischemic pain or control task, during which they completed verbal and non-verbal working memory tests. They also completed measures of state- and trait-level pain catastrophizing. Mediation analyses indicated that state-level pain catastrophizing mediated the relationships of pain group to both verbal and non-verbal working memory, such that participants in the pain group (vs. the control group) catastrophized more about their pain, which then resulted in worse verbal and non-verbal working memory performance. In moderated mediation analyses, trait-level pain catastrophizing moderated this mediation effect for both verbal and non-verbal working memory. Those participants in the pain group who reported greater tendency to catastrophize about pain in general exhibited greater catastrophizing in-the-moment during the pain task, thereby leading to worse verbal and non-verbal working memory performance. These results provide evidence for pain catastrophizing as a putative mechanism and moderating factor of working memory dysfunction in pain. Future research should replicate these results in chronic pain samples, investigate other potential mechanisms (e.g., sleep), and develop interventions to ameliorate cognitive dysfunction by targeting pain catastrophizing.
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    Farm animal contact is associated with progression to Hemolytic uremic syndrome in patients with Shiga toxin-producing Escherichia coli — Indiana, 2012–2018
    (Elsevier, 2020-12) Vachon, Madhura S.; Khalid, Myda; Tarr, Gillian A. M.; Hedberg, Craig; Brown, Jennifer A.; Pediatrics, School of Medicine
    Background: Hemolytic uremic syndrome (HUS) is a life-threatening complication of Shiga toxin-producing Escherichia coli (STEC) infection. The relationship between STEC exposure and severity of clinical outcomes is not well documented. We examined whether direct contact with farm animals increased the likelihood of HUS among Indiana residents diagnosed with STEC. Methods: Exposure data for laboratory-confirmed STEC cases among Indiana residents during 2012-2018 were retrieved. Logistic regression and mediation analysis were performed to determine the extent to which a history of direct contact with farm animals was associated with post-diarrheal HUS independent of age and mediated by stx2 gene presence. Results: A total of 784 STEC cases were retrieved. Of these, 46 (6%) developed HUS. Complete exposure data were available for 600 (77%) cases. A total of 24 (52%) HUS patients reported direct contact with farm animals, while 114 (21%) STEC patients who did not develop HUS reported this exposure. Among all STEC cases, HUS was associated with direct farm animal contact after adjusting for age (OR = 3.40, 95% CI: 1.81, 6.40). Detection of stx2 genes mediated 12% of the association between farm animal contact and HUS. Conclusions: Direct farm animal contact was a risk factor for development of HUS among laboratory-confirmed STEC cases, independent of stx2 presence. Direct farm animal contact should be considered a potential predictor of progression to HUS when patients present for care and the mechanism for its effect on virulence investigated.