Browsing by Author "Vuong, Eileen"

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    Examining the potential role of adiponectin in the development of posttraumatic stress disorder in female rape survivors in South Africa
    (Stellenbosch : Stellenbosch University, 2022-12) Vuong, Eileen; Seedat, Soraya, 1966-; Abrahams, Naeemah; Hemmings, Sian Megan; Peer, Nasheeta; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Psychiatry.
    ENGLISH SUMMARY: Background: Sexual violence, including rape, is associated with adverse mental and physical health outcomes, including post-traumatic stress disorder (PTSD) and cardiometabolic diseases (CMDs). CMDs are prevalent in individuals with PTSD and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis have been implicated in both these disorders. A blood-based biomarker of future susceptibility to PTSD and CMDs following rape, could allow for the early identification of at-risk individuals when disease trajectories may still be reversible. Adiponectin is an anti-inflammatory, insulin-sensitizing, adipose-secreted cytokine that has reciprocal relationships with the HPA axis and cortisol secretion. Higher adiponectin levels have been associated with a lower risk of metabolic syndrome (MetS), a clustering of multiple cardiometabolic risk factors whose pathologic origins arise from insulin resistance and adiposopathy. Although cross-sectional associations between adiponectin and PTSD have been described, no prospective studies of adiponectin in PTSD exist. Aims: In this dissertation, adiponectin is investigated as a candidate biomarker for new-onset PTSD and MetS following rape. Study objectives were completed utilising (1) serum adiponectin levels (s-ADP), (2) adiponectin gene (ADIPOQ) polymorphisms and (3) hair cortisol concentrations (HCC), a HPA axis measure that reflects long-term cortisol production. Methods: This study is nested within the Rape Impact Cohort Evaluation (RICE) study, which enrolled 1 799 black African female participants (N = 852 rape-exposed [RE] and N = 947 rape-unexposed [RUE]) between the ages of 16 and 40 years from KwaZulu-Natal Province. Data collected at baseline and at 3-, 6- and 12-month follow-up visits were utilised in this study to determine prevalent and incident outcomes. This included history (sociodemographic, medical history, mental health), physical examination (anthropometry, blood pressure), and biochemical investigations. Results: A systematic review and meta-analyses of the existing literature demonstrated an inverse association between circulating adiponectin levels and PTSD. In the RICE cohort, higher s- ADP was associated with a reduced risk of PTSD at three and six-month follow-up. However, the interaction of rape x s-ADP on PTSD was not significant. No ADIPOQ variant was shown to be associated with PTSD symptom severity. Serum adiponectin was shown to be significantly associated with MetS prevalence at baseline. However, no associations with new onset MetS incidence were shown at the 12-month follow-up. In the RE, the rs2241766TT genotype was shown to influence s-ADP levels and significantly reduce the risk of MetS incidence at 12 months. Lastly, no evidence of an interactive effect for s-ADP and HCC in predicting PTSD over time was found. Conclusion: This study supports the hypothesis that adiponectin is a potential candidate risk biomarker for PTSD and MetS. Whether adiponectin is a candidate biomarker of risk for PTSD following rape has yet to be established. The lack of prospective association between s-ADP and MetS may be explained by the relatively young study cohort and short period of follow-up and requires further long-term investigation. Future research directions stemming from this PhD include examination for associations of s-ADP and ADIPOQ variants with traumas other than rape, cumulative trauma exposure over time and Mendelian Randomization studies.