Faculty Bibliography

AIMS/OBJECTIVE:Amid changing marijuana policies in the Southern Cone, we examined relationships between marijuana-related risk factors and marijuana use among adolescents in Argentina, Chile, and Uruguay from 2001 to 2016. METHODS:graders and weighted time-varying effect models, we estimated associations between perceived risk (no/low risk versus moderate/great risk) and perceived availability (easy/very easy versus difficult/very difficult/not able to obtain) of marijuana, and any past-month marijuana use. RESULTS:In all countries, marijuana use increased over time and adolescents who perceived no/low risk and easy availability had higher odds of use. In Argentina, the bivariate risk/use association weakened from 2001 (OR = 15.24, 95%CI = 9.63, 24.12) to 2004 [OR = 3.86 (2.72, 5.48)] and strengthened until 2011 [OR = 8.22 (7.56, 10.30)]; the availability/use association strengthened from 2005 [OR = 5.32 (4.05, 6.98)] to 2009 [OR = 20.77 (15.57, 27.70)] and weakened until 2014 [OR = 11.00 (9.11, 13.27)]. In Chile, the risk/use association weakened from 2001 [OR = 7.22 (6.57, 7.95)] to 2015 [OR = 5.58 (4.82, 6.48)]; the availability/use association weakened from 2001 [OR = 5.92 (4.96, 7.06)] to 2015 [OR = 4.10 (3.15, 5.34)]. In Uruguay, the risk/use association weakened from 2003 [OR = 34.22 (22.76, 51.46)] to 2016 [OR = 6.23 (4.96, 7.83)]; the availability/use association weakened from 2005 [OR = 29.13 (13.39, 63.39) to 2007 [OR = 9.42 (3.85, 23.07)], and strengthened until 2016 [OR = 22.68 (12.03, 42.76)]. CONCLUSIONS:Overall, the association between risk and use weakened in all countries, suggesting risk perceptions became a weaker determinant of marijuana use. Perceived availability remained strongly associated with use and may become an increasingly important driver of use (particularly in Uruguay and Argentina).

Individuals with recent/acute HIV-infection have an increased likelihood of disease transmission. To evaluate effectiveness of identifying recent infections, we compared networks of recently and long-term HIV-infected individuals. The Transmission Reduction Intervention Project included two separate arms of recruitment, networks of recently HIV-infected individuals and networks of long-term HIV-infected individuals. Networks of each were recruited and tested for HIV and syphilis infection. The per-seed yield ratios of recruitment were compared between arms. Overall, 84 (41.6%) of 202 participants were identified as HIV-positive. HIV prevalence was higher (p < 0.001) among networks of recent seeds (33/96, 34.4%) compared to long-term seeds (6/31, 19.4%). More individuals were identified with active syphilis infection (p = 0.007) among networks of recent seeds (15/96, 15.6%), compared to networks of long-term seeds (3/31, 9.7%). Network-based recruitment of recently HIV-infected individuals was more effective at identifying HIV and syphilis infection. Allocation of public health resources may be improved by targeting interventions toward networks of recently HIV-infected individuals.

Improved implementation of pre-exposure prophylaxis (PrEP) should be a valuable tool within communities experiencing high HIV incidence, such as black men who have sex with men (MSM). Using baseline data from the Chicago arm of the Transmission Reduction Intervention Project (TRIP), we examined awareness and use of PrEP within HIV potential transmission networks. Transmission Reduction Intervention Project recruited participants ages 18-69 (N = 218) during 2014-2016 from networks originating from recently and chronically HIV-infected MSM and transgender persons. In total, 53.2% of participants had heard of PrEP, while 8 (6.5%) HIV-negative participants reported ever using PrEP. In multivariable regression, PrEP awareness was associated with identifying as gay, attending some college or higher, having an HIV test in the previous 6 months, and experiencing HIV-related social support. PrEP awareness was not associated with experiencing or observing HIV-related stigma. PrEP use was associated with participants knowing two or more other PrEP-users. These findings demonstrate moderate awareness, but low uptake of PrEP within HIV potential transmission networks in Chicago. Future research should explore how to increase PrEP use in these networks and investigate the social dynamics behind our finding that PrEP users are more likely to know other PrEP users.

Social science and public health literature has framed residential segregation as a potent structural determinant of the higher HIV burden among black heterosexuals, but empirical evidence has been limited. The purpose of this study is to test, for the first time, the association between racial segregation and newly diagnosed heterosexually acquired HIV cases among black adults and adolescents in 95 large US metropolitan statistical areas (MSAs) in 2008-2015. We operationalized racial segregation (the main exposure) using Massey and Denton's isolation index for black residents; the outcome was the rate of newly diagnosed HIV cases per 10,000 black adult heterosexuals. We tested the relationship of segregation to this outcome using multilevel multivariate models of longitudinal (2008-2015) MSA-level data, controlling for potential confounders and time. All covariates were lagged by 1 year and centered on baseline values. We preliminarily explored mediation of the focal relationship by inequalities in education, employment, and poverty rates. Segregation was positively associated with the outcome: a one standard deviation decrease in baseline isolation was associated with a 16.2% reduction in the rate of new HIV diagnoses; one standard deviation reduction in isolation over time was associated with 4.6% decrease in the outcome. Exploratory mediation analyses suggest that black/white socioeconomic inequality may mediate the relationship between segregation and HIV. Our study suggests that residential segregation may be a distal determinant of HIV among black heterosexuals. The findings further emphasize the need to address segregation as part of a comprehensive strategy to reduce racial inequities in HIV.

Identifying and linking people to care soon after HIV infection could limit viral transmission and protect their health. This work aims at describing the continuum of care among recently HIV-infected people who inject drugs (PWID) and participated in an intervention in the context of an HIV outbreak in Athens, Greece. The Transmission Reduction Intervention Project (TRIP) conducted risk network-based contact tracing and screened people for recent HIV infection. A comprehensive approach with a case management component that aimed to remove barriers to accessing care was adopted. Follow-up data on antiretroviral treatment (ART) and HIV-RNA levels were obtained from HIV clinics. TRIP enrolled 45 recently HIV-infected PWID (80% male) with a median viral load at recruitment of 5.43 log₁₀ copies/mL. Of the recently infected persons in TRIP, 87% were linked to care; of these, 77% started ART; and of those on ART, 89% achieved viral load <200 copies/mL. TRIP and its public health allies managed to get most of the recently HIV-infected PWID who were identified by the program into care and many of them onto ART. This resulted in very low HIV-RNA levels. Treatment as prevention can work if individuals are aided in overcoming difficulties in entry to, or attrition from care.

This ecologic cohort study explores the relationship between state minimum wage laws and rates of HIV diagnoses among heterosexual black residents of U.S metropolitan areas over an 8-year span. Specifically, we applied hierarchical linear modeling to investigate whether state-level variations in minimum wage laws, adjusted for cost-of-living and inflation, were associated with rates of new HIV diagnoses among heterosexual black residents of metropolitan statistical areas (MSAs; n=73), between 2008 and 2015. Findings suggest that an inverse relationship exists between baseline state minimum wages and initial rates of newly diagnosed HIV cases among heterosexual black individuals, after adjusting for potential confounders. MSAs with a minimum wage that was $1 higher at baseline had a 27.12% lower rate of newly diagnosed HIV cases. Exploratory analyses suggest that income inequality may mediate this relationship. If subsequent research establishes a causal relationship between minimum wage and this outcome, efforts to increase minimum wages should be incorporated into HIV prevention strategies for this vulnerable population.

INTRODUCTION/BACKGROUND:We sought to understand the association between youthful self-harm and subsequent chronic disease-related healthcare utilization and whether self-harm reflects unique vulnerability in comparison with severe psychiatric disorders. METHODS:We used a retrospective matched cohort design with statewide, all-payer, individually linked emergency department (ED) data from California, USA. Risk of future ED visits for common chronic conditions in adolescence (headaches, asthma, epilepsy, diabetes, and gastrointestinal disorders, assessed using ICD-9 diagnoses) were compared between three adolescent study groups presenting to an ED in 2010: self-harm patients (n = 5,484), patients with psychiatric complaints but no self-harm (n = 14,235), and patients with other complaints (n = 16,452). Cohort follow-up ended on Sept. 30, 2015. Analyses were adjusted for patients' prior histories of ED utilization for chronic conditions as well as patient- and area-level sociodemographic characteristics. RESULTS:Risk of subsequent ED visits was higher among self-harm patients compared to non-psychiatric control patients for subsequent epilepsy- (aRR = 1.77, 95% CI [1.42, 2.21]). Risk of subsequent ED visits was higher among psychiatric patients compared to non-psychiatric control patients for subsequent headache- (aRR = 1.31, 95% CI [1.21, 1.42]), and epilepsy-related problems (aRR = 1.85, 95% CI [1.55, 2.21]). Self-harm patients were at higher risk than psychiatric patients for subsequent gastrointestinal disorder (aRR = 1.76, 95% CI [1.03, 3.01]). CONCLUSIONS:Findings suggest that self-harm behavior and psychiatric disorders are associated with increased ED utilization for subsequent chronic disease-related ED utilization. Chronic disease among adolescent psychiatric patients should be attended to, potentially involving new models of clinical follow-up care.

OBJECTIVE:To determine whether restrictiveness-permissiveness of state gun laws or gun ownership are associated with mass shootings in the US. DESIGN/METHODS:Cross sectional time series. SETTING AND POPULATION/METHODS:US gun owners from 1998-2015. EXPOSURE/METHODS:An annual rating between 0 (completely restrictive) and 100 (completely permissive) for the gun laws of all 50 states taken from a reference guide for gun owners traveling between states from 1998 to 2015. Gun ownership was estimated annually as the percentage of suicides committed with firearms in each state. MAIN OUTCOME MEASURE/METHODS:Mass shootings were defined as independent events in which four or more people were killed by a firearm. Data from the Federal Bureau of Investigation's Uniform Crime Reporting System from 1998-2015 were used to calculate annual rates of mass shootings in each state. Mass shooting events and rates were further separated into those where the victims were immediate family members or partners (domestic) and those where the victims had other relationships with the perpetrator (non-domestic). RESULTS:Fully adjusted regression analyses showed that a 10 unit increase in state gun law permissiveness was associated with a significant 11.5% (95% confidence interval 4.2% to 19.3%, P=0.002) higher rate of mass shootings. A 10% increase in state gun ownership was associated with a significant 35.1% (12.7% to 62.7%, P=0.001) higher rate of mass shootings. Partially adjusted regression analyses produced similar results, as did analyses restricted to domestic and non-domestic mass shootings. CONCLUSIONS:States with more permissive gun laws and greater gun ownership had higher rates of mass shootings, and a growing divide appears to be emerging between restrictive and permissive states.

Systems science models use computer-based algorithms to model dynamic interactions between study units within and across levels and are characterized by nonlinear and feedback processes. They are particularly valuable approaches that complement the traditional epidemiologic toolbox in cases in which real data are not available and in cases in which traditional epidemiologic methods are limited by issues such as interference, spatial dependence, and dynamic feedback processes. In this commentary, we propose 2 key contributions that systems models can make to epidemiology: 1) the ability to test assumptions about underlying mechanisms that give rise to population distributions of disease; and 2) help in identifying the types of interventions that have the greatest potential to reduce population rates of disease in the future or in new sites where they have not yet been implemented. We discuss central challenges in the application of systems science approaches in epidemiology, propose potential solutions, and predict future developments in the role that systems science can play in epidemiology.

OBJECTIVES/OBJECTIVE:To estimate associations between psychiatric disorders and gun carrying among adolescents and to estimate the total number of adolescents in the US who have psychiatric disorders and report carrying guns. STUDY DESIGN/METHODS:We used cross-sectional data from the National Comorbidity Survey - Adolescent Supplement, a nationally representative sample of adolescents age 13-18 years (N = 10 123; response rate = 75.6%). Psychiatric disorders were assessed using the Composite International Diagnostic Interview. Gun carrying in the 30 days prior to the interview was assessed by self-report. We used multivariable Poisson regression to test for associations. RESULTS:The analytic sample included 10 112 adolescents, 2.4% of whom reported carrying a gun in the prior 30 days. The prevalence of gun carrying was greater among adolescents with conduct disorder (adjusted prevalence ratio [APR] = 1.88, 95% CI 1.38, 2.57), drug use disorders (APR = 1.91, 95% CI 1.05, 3.45), and specific phobias (APR = 1.54, 95% CI 1.07, 2.22) compared with adolescents without these disorders. We estimated that 1.1% (95% CI 0.77, 1.48) of adolescents with a disorder associated with self- or other-directed violence also carry guns. Nationally, that is approximately 272 000 adolescents with both risk factors. CONCLUSIONS:Specific psychiatric disorders are associated with an increased risk of gun carrying among adolescents, but the vast majority of adolescents with psychiatric disorders did not report gun carrying. Targeted efforts to assess access to and use of firearms in mental healthcare and other clinical settings are important, as are efforts to identify population approaches to prevention.