Browsing by Author "Koenen, Karestan"

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    The BDNF p.Val66Met polymorphism, childhood trauma, and brain volumes in adolescents with alcohol abuse
    (BioMed Central, 2014-12-16) Dalvie, Shareefa; Stein, Dan J; Koenen, Karestan; Cardenas, Valerie; Cuzen, Natalie L; Ramesar, Raj; Fein, George; Brooks, Samantha J
    Background: Previous studies have indicated that early life adversity, genetic factors and alcohol dependence are associated with reduced brain volume in adolescents. However, data on the interactive effects of early life adversity, genetic factors (e.g. p.Met66 allele of BDNF), and alcohol dependence, on brain structure in adolescents is limited. We examined whether the BDNF p.Val66Met polymorphism interacts with childhood trauma to predict alterations in brain volume in adolescents with alcohol use disorders (AUDs). Methods: We examined 160 participants (80 adolescents with DSM-IV AUD and 80 age- and gender-matched controls) who were assessed for trauma using the Childhood Trauma Questionnaire (CTQ). Magnetic resonance images were acquired for a subset of the cohort (58 AUD and 58 controls) and volumes of global and regional structures were estimated using voxel-based morphometry (VBM). Samples were genotyped for the p.Val66Met polymorphism using the TaqMan® Assay. Analysis of covariance (ANCOVA) and post-hoc t-tests were conducted using SPM8 VBM. Results: No significant associations, corrected for multiple comparisons, were found between the BDNF p.Val66Met polymorphism, brain volumes and AUD in adolescents with childhood trauma. Conclusions: These preliminary findings suggest that the BDNF p.Met66 allele and childhood trauma may not be associated with reduced structural volumes in AUD. Other genetic contributors should be investigated in future studies.
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    Maternal blood contamination of collected cord blood can be identified using DNA methylation at three CpGs
    (BioMed Central, 2017-07-25) Morin, Alexander M; Gatev, Evan; McEwen, Lisa M; MacIsaac, Julia L; Lin, David T S; Koen, Nastassja; Czamara, Darina; Räikkönen, Katri; Zar, Heather J; Koenen, Karestan; Stein, Dan J; Kobor, Michael S; Jones, Meaghan J
    Background: Cord blood is a commonly used tissue in environmental, genetic, and epigenetic population studies due to its ready availability and potential to inform on a sensitive period of human development. However, the introduction of maternal blood during labor or cross-contamination during sample collection may complicate downstream analyses. After discovering maternal contamination of cord blood in a cohort study of 150 neonates using Illumina 450K DNA methylation (DNAm) data, we used a combination of linear regression and random forest machine learning to create a DNAm-based screening method. We identified a panel of DNAm sites that could discriminate between contaminated and non-contaminated samples, then designed pyrosequencing assays to pre-screen DNA prior to being assayed on an array. Results: Maternal contamination of cord blood was initially identified by unusual X chromosome DNA methylation patterns in 17 males. We utilized our DNAm panel to detect contaminated male samples and a proportional amount of female samples in the same cohort. We validated our DNAm screening method on an additional 189 sample cohort using both pyrosequencing and DNAm arrays, as well as 9 publically available cord blood 450K data sets. The rate of contamination varied from 0 to 10% within these studies, likely related to collection specific methods. Conclusions: Maternal blood can contaminate cord blood during sample collection at appreciable levels across multiple studies. We have identified a panel of markers that can be used to identify this contamination, either post hoc after DNAm arrays have been completed, or in advance using a targeted technique like pyrosequencing.
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    Trauma and posttraumatic stress disorder in South Africa
    (2015) Atwoli, Lukoye; Stein, Dan; Koenen, Karestan
    Objective: The main aim of this thesis is to analyze data from the South African Stress and Health (SASH) study and , for the first time, generate information on the epidemiology of traumatic event s (TEs) and posttraumatic stress disorder (PTSD), and on the association of TEs with other psychopathological and physical health outcomes. Methods: A literature review was done to provide information current knowledge in the field. Cross - tabulations, Chi - squared tests and logistic regression analyses were then conducted SASH data to determine the prevalence of the different types of trauma and PTSD and the associations between the sociodemographic variables and TEs and PTSD on the one hand, and TEs and PTSD, other psychopathology and chronic physical conditions on the other . Results: The most common traumatic events were the unexpected death of a loved one and witnessing trauma. Lifetime prevalence of PTSD was 2.3%, and the conditional prevalence of PTSD after trauma exposure was 3.5%. PTSD conditional risk and burden were both highest for witnessing trauma. Witnessing trauma was commonest among males and those with low - average education. There was statistically significant association between witnessing and PTSD, mood, and anxiety disorders. Exposure to any TE significantly increased the odds of all the physical conditions, and the odds of having a physical condition were directly related to the number of lifetime traumatic events. Sexual violence and unexpected death of a loved one significantly increased the odds of all the e physical conditions assessed, while war events were only associated with respiratory conditions. Apart from war events, accidents and witnessing trauma were associated with the fewest physical conditions. Conclusions: Consistent with the literature, trauma and PTSD in South Africa are not distributed according to the socio - demographic factors or trauma types observed in other countries. Witnessing trauma is common in South Africa and increases the risk of mood and anxiety disorders. Finally, TE exposure is associated with chronic physical conditions in a dose - response manner. Trauma interventions must therefore focus also on those not directly affected, and routine evaluation for chronic physical conditions is recommended for survivors of all trauma.
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    Trauma and posttraumatic stress disorder in South Africa: analysis from the South African Stress and Health Study
    (BioMed Central Ltd, 2013) Atwoli, Lukoye; Stein, Dan; Williams, David; Mclaughlin, Katie; Petukhova, Maria; Kessler, Ronald; Koenen, Karestan
    BACKGROUND: South Africa's unique history, characterised by apartheid, a form of constitutional racial segregation and exploitation, and a long period of political violence and state-sponsored oppression ending only in 1994, suggests a high level of trauma exposure in the general population. The aim of this study was to document the epidemiology of trauma and posttraumatic stress disorder (PTSD) in the South African general population. METHODS: The South African Stress and Health Study is a nationally representative survey of South African adults using the WHO's Composite International Diagnostic Interview (CIDI) to assess exposure to trauma and presence of DSM-IV mental disorders. RESULTS: The most common traumatic events were the unexpected death of a loved one and witnessing trauma occurring to others. Lifetime and 12-month prevalence rates of PTSD were 2.3% and 0.7% respectively, while the conditional prevalence of PTSD after trauma exposure was 3.5%. PTSD conditional risk after trauma exposure and probability of chronicity after PTSD onset were both highest for witnessing trauma. Socio-demographic factors such as sex, age and education were largely unrelated to PTSD risk. CONCLUSIONS: The occurrence of trauma and PTSD in South Africa is not distributed according to the socio-demographic factors or trauma types observed in other countries. The dominant role of witnessing in contributing to PTSD may reflect the public settings of trauma exposure in South Africa and highlight the importance of political and social context in shaping the epidemiology of PTSD.