Katherine P. Theall

The Role of the Dopamine Transporter (DAT) in the Development of PTSD in Preschool Children

Population-based association studies have supported the heritability of posttraumatic stress disorder (PTSD). This study explored the influence of genetic variation in the dopamine transporter (DAT) 3 untranslated region variable number tandem repeat on the development of PTSD in preschool children exposed to Hurricane Katrina, diagnosed using a developmentally appropriate semistructured interview. A diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition , (DSM-IV; American Psychiatric Association, 1994), total symptoms, and specifically Criterion D symptoms were significantly more likely to be found in children with the 9 allele. This study replicates a previous finding in adults with PTSD. The specificity of this finding to the increased arousal symptoms of Criterion D suggests that dopamine and the DAT allele may contribute to one heritable path in a multifinality model of the development of PTSD.

Impact of small group size on neighbourhood influences in multilevel models

Background Given the growing availability of multilevel data from national surveys, researchers interested in contextual effects may find themselves with a small number of individuals per group. Although there is a growing body of literature on sample size in multilevel modelling, few have explored the impact of group sizes of less than five. Methods In a simulated analysis of real data, the impact of a group size of less than five was examined on both a continuous and dichotomous outcome in a simple two-level multilevel model. Models with group sizes one to five were compared with models with complete data. Four different linear and logistic models were examined: empty models; models with a group-level covariate; models with an individual-level covariate and models with an aggregated group-level covariate. The study evaluated further whether the impact of small group size differed depending on the total number of groups. Results When the number of groups was large (N=459), neither fixed nor random components were affected by small group size, even when 90% of tracts had only one individual per tract and even when an aggregated group-level covariate was examined. As the number of groups decreased, the SE estimates of both fixed and random effects were inflated. Furthermore, group-level variance estimates were more affected than were fixed components. Conclusions Datasets in which there is a small to moderate number of groups, with the majority of very small group size (n<5), size may fail to find or even consider a group-level effect when one may exist and also may be underpowered to detect fixed effects.

Integrating Social Capital Into a Park-Use and Active-Living Framework

BACKGROUNDnParks have been proposed as a feature of the built environment that may promote increased physical activity. Little, if any, research has investigated the role of the park social environment in promoting physical activity within parks, however.nnnPURPOSEnTo examine whether social capital is a collective feature of the park environment and whether it is associated with park use and park-based physical activity.nnnMETHODSnAdult park users (n=222) were surveyed in 27 neighborhood parks in New Orleans LA in July-August 2008. Direct observation methods were used to count the numbers and activity levels of all park users in these parks on weekdays during the hours of 4:00-7:00(PM). Multilevel linear regression models were used to calculate the intraclass correlation (ICC), which measures the variation in perceived social capital attributable to differences among parks and to test whether park use and physical activity outcomes differed between parks with high versus low levels of social capital. Analyses were conducted in 2009-2010.nnnRESULTSnIn study parks, 27% of perceived social capital was attributable to differences among parks (ICC=0.27). Parks with higher levels of social capital had higher daily numbers of observed park users (42.5 vs 12.1, p=0.0044) and had more energy expended within the park (3200.3 vs 721.2 MET-minutes across all park users, p=0.0087).nnnCONCLUSIONSnInterventions to improve park social environments should be conducted to determine if they promote increased physical activity among park users.

Accessibility and effectiveness of sources of information about HIV/AIDS in a rural population

Objectives To determine the accessibility and effectiveness of different sources of information about human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) in a rural population. Methods A total of 152 (58.6% women, 76.2% nonwhite) respondents living in rural southeast Louisiana completed a questionnaire assessing demographics, exposure to information about HIV/AIDS, and prevalence of HIV-related risk and protective behaviors. Differences by number and type of information sources accessed in prevalence of these behaviors were assessed using regression and multivariate analyses of variance. Results HIV-related information was widely accessible, with most respondents having obtained information from mass media and approximately half having been exposed to information from small media and interpersonal contacts. Small media and interpersonal source exposure was positively associated with greater likelihood of asking casual and steady partners about their HIV status. Although it was the most common factor, exposure to information from mass media was overall not significantly associated with the prevalence of risk or protective behaviors. Conclusions HIV-related information sources are being used by individuals living in rural regions. Unfortunately, exposure to such information was only weakly or not at all associated with the prevalence of most risk and protective factors. It can be concluded that HIV-related information, although accessible, has at best minimal effects on behaviors. More work is needed to increase the effectiveness of information about HIV/AIDS disseminated in rural regions.

Knowledge, Attitudes and Practice Relating to Hazardous Alcohol Use across the Continuum of Care in a Community Healthcare Centre.

Alcohol screening and intervention in community health settings places a great time demand on practitioners. Thus, implementation of practitioner-delivered intervention is challenging. Aims: The aim of this study was to assess the feasibility of incorporating a brief alcohol intervention into daily practices of a community health care centre by utilizing assistance from non-practitioners and administrative staff. Methods: In regard to alcohol use, the knowledge, attitudes and practice (KAP) of the staff of a health care centre were assessed using a self-administered survey. The 57-item survey consisted of alcohol-relevant questions in four domains: clinical practice, knowledge and self-assessment of skills and available resources. Findings: The sample consisted of 70 individuals—23 practitioners, 21 medical assistants and 26 administrative staff from two New Orleans’ clinics. Practitioners were observed to be most confident in assessing alcoholism as well as in implementing interventions for alcohol abuse. Medical assistants exhibited high self-rated scores, second to practitioners, in survey items regarding attitudes towards patients, alcohol knowledge and alcohol-related clinical skills. Conclusions: Based on KAP, it appears that healthcare workers other than practitioners, particularly medical assistants, may serve as a useful resource to practitioners in providing alcohol screening and prevention services. Education and empowerment of medical assistants will however be needed to achieve this goal.