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Needle exchange programs for the prevention of hepatitis C virus infection in people who inject drugs : A systematic review with meta-analysis
(2017-05-17) Davis, Stephen M.; Daily, Shay; Kristjansson, Alfgeir L.; Kelley, George A.; Zullig, Keith; Baus, Adam; Davidov, Danielle; Fisher, Melanie; Department of Psychology
Background: Previous research on the effectiveness of needle exchange programs (NEP) in preventing hepatitis C virus (HCV) in people who inject drugs (PWID) has shown mixed findings. The purpose of this study was to use the meta-analytic approach to examine the association between NEP use and HCV prevention in PWIDs. Methods: Study inclusion criteria were (1) observational studies, (2) PWIDs, (3) NEP use, (4) HCV status ascertained by serological testing, (5) studies published in any language since January 1, 1989, and (6) data available for measures of association. Studies were located by searching four electronic databases and cross-referencing. Study quality was assessed using the Newcastle Ottawa (NOS) scale. A ratio measure of association was calculated for each result from cohort or case-control studies and pooled using a random effects model. Odds ratio (OR) and hazard ratio (HR) models were analyzed separately. Results were considered statistically significant if the 95% confidence interval (CI) did not cross 1. Heterogeneity was estimated using Q and I 2 with alpha values for Q ≤ 0.10 considered statistically significant. Results: Of the 555 citations reviewed, 6 studies containing 2437 participants were included. Studies had an average NOS score of 7 out of 9 (77.8%) stars. Concerns over participant representativeness, unclear adjustments for confounders, and bias from participant nonresponse and loss to follow-up were noted. Results were mixed with the odds ratio model indicating no consistent association (OR, 0.51, 95% CI, 0.05-5.15), and the hazard ratio model indicating a harmful effect (HR, 2.05, 95% CI, 1.39-3.03). Substantial heterogeneity (p ≤ 0.10) and moderate to large inconsistency (I 2 ≥ 66%) were observed for both models. Conclusions: The impact of NEPs on HCV prevention in PWIDs remains unclear. There is a need for well-designed research studies employing standardized criteria and measurements to clarify this issue.
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Energy drink consumption and substance use risk in middle school students
(2016-06-01) Mann, Michael J.; Smith, Megan L.s.; Kristjansson, Alfgeir L.; Department of Psychology
Objectives: Energy drink (ED) sales have increased greatly in recent years and ED is now a common topic in health behavior research. Most studies work with samples of college students and/or young adults and to a lesser degree with high school students. Research is lacking on ED consumption in younger users. The purpose of this study was to fill this gap and assess the prevalence of ED consumption in a sample of middle school students as well to analyze the relationships between ED use and illicit and licit drug use in girls and boys of this age. Method: We use cross-sectional school-survey data from 6-8th grade students in three US mid-Atlantic schools conducted in September to November 2014 (N = 1152, response rate: 82.4%). Results: Approximately 20% of participants had consumed ED and 10% had smoked cigarettes. Almost 14% had used alcohol at least once in their lifetime and 5.5% marijuana. Boys were more likely than girls to have used ED but no gender difference was observed in the prevalence of illicit substances. However, ED use was positively related to smoking and alcohol use among both genders, but also to several forms of illicit drug use among girls. Conclusion: ED consuming girls are particularly prone to also use illicit substances. This is the first survey-type study which reports a positive relationship between ED consumption with both licit and illicit drug use in middle school-aged girls and boys.
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Needs assessment of school and community physical activity opportunities in rural West Virginia : The McDowell CHOICES planning effort Health behavior, health promotion and society
(2015-04-03) Kristjansson, Alfgeir L.; Elliott, Eloise; Bulger, Sean; Jones, Emily; Taliaferro, Andrea R.; Neal, William; Department of Psychology
Background: McDowell CHOICES (Coordinated Health Opportunities Involving Communities, Environments, and Schools) Project is a county wide endeavor aimed at increasing opportunities for physical activity (PA) in McDowell County, West Virginia (WV). A comprehensive needs-assessment laid the foundation of the project. Methods: During the 6 month needs assessment, multiple sources of data were collected in two Town Hall Meetings (n∈=∈80); a student online PA interest survey (n∈=∈465); a PA and nutrition survey among 5th (10-11 years) and 8th graders (13-14 years) with questions adapted from the CDC's Youth Risk Behavior Surveillance Survey (n∈=∈442, response rate =∈82.2%); six semi-structured school and community focus groups (n∈=∈44); school site visits (n∈=∈11); and BMI screening (n∈=∈550, response rate∈=∈69.7%). Results: One third of children in McDowell County meet the national PA minimum of 60 minutes daily. At least 40% of 5th and 8th graders engage in electronic screen activity for 3 hours or more every day. The prevalence of obesity in 5th graders is higher in McDowell County than the rest of WV (∼55% vs. 47% respectively). SWOT analyses of focus group data suggest an overall interest in PA but also highlight a need for increase in structured PA opportunities. Focus group data also suggested that a central communication (e.g. internet-based) platform would be beneficial to advertise and boost participation both in current and future programs. Schools were commonly mentioned as potential facilities for public PA participation throughout the county, both with regards to access and convenience. School site visits suggest that schools need more equipment and resources for before, during, and after school programs. Conclusions: An overwhelming majority of participants in the McDowell CHOICES needs assessment were interested to participate in more PA programs throughout the county as well as to improve opportunities for the provision of such programs. Public schools were widely recognized as the hub of the communities and provide the best venue for PA promotion for both students and adult citizens, and can potentially serve as a platform for change in rural communities such as McDowell County.
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Prevalence of overweight in 2 to 17 year-old children and adolescents whose parents live separately : A Nordic cross-sectional study
(2014) Hohwü, Lena; Gissler, Mika; Sjöberg, Agneta; Biehl, Anna M.; Kristjansson, Alfgeir L.; Obel, Carsten; Department of Psychology
Background: Comparative data of parental separation and childhood overweight has not been available before across the Nordic countries. The aim of this study was to examine the within-country prevalence and association between parental cohabitation and overweight in Nordic children. Methods: A cross-sectional survey of 2-17-year-old children was conducted in 2011, titled: "NordChild". A random sample of 3,200 parents in each of the Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden were invited to participate in the study with parents of 6,609 children accepting to give answers about their children's health and welfare including information on height and weight of each child and parental cohabitation (response rate 41.5%). The group differences in prevalence and adjusted odds ratio (OR) for overweight, with corresponding 95% confidence intervals (CI) were performed in children whose parents lived separately. Additionally, a missing data analysis was performed to determine whether the adjusted estimates might result from confounding or selection bias. Results: A significant difference was observed in Iceland between children whose parents live separately compared to those who live with both parents (difference: 9.4%, 95% CI: 2.8; 15.9) but no such difference was observed in Denmark, Finland, Norway and Sweden. No significant odds of overweight were observed in children whose parents lived separately compared to children in normal weight at the time of study; Denmark: OR 1.03 (95% CI: 0.42; 2.53), Finland: OR 1.27 (95% CI: 0.74; 2.20), Iceland: OR 1.50 (95% CI: 0.79; 2.84), Norway: OR 1.46 (95% CI: 0.81; 2.62), and Sweden: 1.07 (95% CI: 0.61; 1.86). The missing data analysis indicated that the findings in Norway, Finland and Iceland were partly observed due to selection effects, whereas the adjustment in Denmark was due to confounding. The crude OR for overweight was higher in the 2-9-year-old group than in the 10-17-year-old group whose parents lived separately in Iceland, Norway and Sweden. Conclusions: No association between parental cohabitation and overweight in Nordic children was found. Our finding of greater prevalence of overweight in Icelandic children whose parents live separately may be an indication that the welfare system in Iceland is separating from the other Nordic countries.
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Scaling properties of multi-fidelity shape optimization algorithms
(2012) Koziel, Slawomir; Leifsson, Leifur; Department of Engineering
Multi-fidelity optimization can be utilized for efficient design of airfoil shapes. In this paper, we investigate the scaling properties of algorithms exploiting this methodology. In particular, we study the relationship between the computational cost and the size of the design space. We focus on a specific optimization technique where, in order to reduce the design cost, the accurate high-fidelity airfoil model is replaced by a cheap surrogate constructed from a low-fidelity model and the shape-preserving response prediction technique. In this study, we consider the design of transonic airfoils and use the compressible Euler equations in the high-fidelity computational fluid dynamic (CFD) model. The low-fidelity CFD model is same as the high-fidelity one, but with coarser mesh resolution and reduced level of solver converge. The number of design variables varies from 3 to 11 by using NACA 4-digit airfoil shapes as well as airfoils constructed by Bézier curves. The results of the three optimization studies show that total cost increases from about 12 equivalent high-fidelity model evaluations to 34. The number of high-fidelity evaluations increases from 4 to 9, whereas the number of low-fidelity evaluations increases more rapidly, from 600 to 2000. This indicates that, while the overall optimization cost scales more or less linearly with the dimensionality of the design space, further cost reduction can be obtained through more efficient optimization of the surrogate model.

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