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Open Access Publications from the University of California

Scholarly Works (9 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2022)

Background: Methamphetamine use is highly prevalent among men who have sex with men and particularly those living with HIV, but knowledge of the long-term dynamics and associated health outcomes is limited. This study aimed to longitudinally investigate the interdependence between methamphetamine use, sleep deficiency and sexual and HIV risk behaviors among men who have sex with men living with or at high risk of acquiring HIV in Los Angeles, CA.

Methods: All analyses used data collected between August 2014 and February 2022 from a cohort of men who have sex with men living with or at high risk of acquiring HIV in Los Angeles, CA. Chapter 2 used a multistate Markov model to compare natural histories of methamphetamine use by HIV-status and substance use treatment status. Chapter 3 used logistic regression and conditional growth curve models to investigate the association of methamphetamine use with sleep deficiency. Chapter 4 used logistic regression to examine the joint association of sleep deficiency and methamphetamine use with sexual risk behaviors, HIV risk behaviors, STI incidence, and HIV viral load.

Results: In Chapter 2, those living with HIV were less likely to transition from no to occasional methamphetamine use and from occasional to no methamphetamine use. Those who reported receiving substance use treatment at a study visit were more likely to have decreased methamphetamine use at their next study visit. In Chapter 3, those who reported methamphetamine use were more likely to experience sleep deficiency than those who reported no substance use; among those who reported methamphetamine use, depressive symptoms and unstable housing were associated with sleep deficiency. In Chapter 4, sleep deficiency, particularly among those who used methamphetamine occasionally, was associated with having at least one new anal sex partner, having concurrent partners, having exchange sex, attending a sex party, and missed HIV medications.

Conclusions: The prevalence of both methamphetamine use and sleep deficiency are high among men who have sex with men living with or at high risk of acquiring HIV. Taken together, these findings highlight the need for interventions that reduce frequency of methamphetamine use, which may in turn improve sleep hygiene and reduce risk behaviors.

    Cover page: Characterizing the dynamic relationship between methamphetamine use, sleep, and sexual risk behaviors in men who have sex with men living with or at high risk of acquiring HIV in Los Angeles
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2014)

    Background

    Stroke is a major cause of morbidity and mortality. We describe trends in the incidence, outcomes, and risk factors for stroke in the US Medicare population from 1988 to 2008.

    Methods

    We analyzed data from a 20% sample of hospitalized Medicare beneficiaries with a principal discharge diagnosis of ischemic (n = 918,124) or hemorrhagic stroke (n = 133,218). Stroke risk factors were determined from the National Health and Nutrition Examination Survey (years 1988-1994, 2001-2008) and medication uptake from the Medicare Current Beneficiary Survey (years 1992-2008). Primary outcomes were stroke incidence and 30-day mortality after stroke hospitalization.

    Results

    Ischemic stroke incidence decreased from 927 per 100,000 in 1988 to 545 per 100,000 in 2008, and hemorrhagic stroke decreased from 112 per 100,000 to 94 per 100,000. Risk-adjusted 30-day mortality decreased from 15.9% in 1988 to 12.7% in 2008 for ischemic stroke and from 44.7% to 39.3% for hemorrhagic stroke. Although observed stroke rates decreased, the Framingham stroke model actually predicted increased stroke risk (mean stroke score 8.3% in 1988-1994, 8.8% in 2005-2008). Statin use in the general population increased (4.0% in 1992, 41.4% in 2008), as did antihypertensive use (53.0% in 1992, 73.5% in 2008).

    Conclusions

    Incident strokes in the Medicare population aged ≥65 years decreased by approximately 40% over the last 2 decades, a decline greater than expected on the basis of the population's stroke risk factors. Case fatality from stroke also declined. Although causality cannot be proven, declining stroke rates paralleled increased use of statins and antihypertensive medications.
      Cover page: Trends in Stroke Rates, Risk, and Outcomes in the United States, 1988 to 2008
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2022)
      The objective was to examine the impact of the COVID-19 pandemic on mental health care, cannabis use, and behaviors that increase the risk of STIs among men living with or at high risk for HIV. Data were from mSTUDY - a cohort of men who have sex with men in Los Angeles, California. Participants who were 18 to 45 years and a half were HIV-positive. mSTUDY started in 2014, and at baseline and semiannual visits, information was collected on substance use, mental health, and sexual behaviors. We analyzed data from 737 study visits from March 2020 through August 2021. Compared to visits prior to the COVID-19 pandemic, there were significant increases in depressive symptomatology (CES-D ≥ 16) and anxiety (GAD-7 ≥ 10). These increases were highest immediately following the start of the pandemic and reverted to pre-pandemic levels within 17 months. Interruptions in mental health care were associated with higher substance use (especially cannabis) for managing anxiety/depression related to the pandemic (50% vs. 31%; p-value < .01). Cannabis use for managing pandemic-related anxiety/depression was higher among those reporting changes in sexual activity (53% vs. 36%; p-value = 0.01) and was independently associated with having more than one sex partner in the prior 2 weeks (adjusted OR = 1.5; 95% CI 1.0-2.4). Our findings indicate increases in substance use, in particular cannabis, linked directly to experiences resulting from the COVID-19 pandemic and the associated interruptions in mental health care. Strategies that deliver services without direct client contact are essential for populations at high risk for negative sexual and mental health outcomes.
        Cover page: Interruptions in Mental Health Care, Cannabis Use, Depression, and Anxiety during the COVID-19 Pandemic: Findings from a Cohort of HIV-Positive and HIV-Negative MSM in Los Angeles, California
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2024)

        Introduction

        Methamphetamine use is highly prevalent among men who have sex with men (MSM), but knowledge of the long-term dynamics, and how they are affected by substance use treatment, is limited. This study aimed to describe trajectories of methamphetamine use among MSM, and to evaluate the impact of treatment for any kind of substance use on frequency of methamphetamine use.

        Methods

        This analysis used data from a cohort of MSM in Los Angeles, CA, who participated in semi-annual study visits from 2014 to 2022. The study characterized trajectories of methamphetamine use using a continuous time multistate Markov model with three states. States were defined using self-reported frequency of methamphetamine use in the past six months: frequent (daily), occasional (weekly or less), and never. The model estimated the association between receiving treatment for any kind of substance use and changes in state of frequency of methamphetamine use.

        Results

        This analysis included 2348 study visits among 285 individuals who were followed-up for an average of 4.4 years. Among participants who were in the frequent use state, 65 % (n = 26) of those who were receiving any kind of substance use treatment at a study visit had reduced their methamphetamine use at their next visit, compared to 33 % (n = 95) of those who were not receiving treatment. Controlling for age, race/ethnicity, and HIV-status, those who reported receiving current treatment for substance use were more likely to transition from occasional to no use (HR: 1.63, 95 % CI: 1.10-2.42) and frequent to occasional use (HR: 4.25, 95 % CI: 2.11-8.59) in comparison to those who did not report receiving current treatment for substance use.

        Conclusions

        Findings from this dynamic modeling study provide a new method for assessing longitudinal methamphetamine use outcomes and add important evidence outside of clinical trials that substance use treatment may reduce methamphetamine use.
          Cover page: Association of current substance use treatment with future reduced methamphetamine use in an observational cohort of men who have sex with men in Los Angeles
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2023)

          Introduction

          Novel strategies are needed to address barriers to COVID-19 vaccination among people experiencing homelessness (PEH), a population that faces increased COVID-19 risk. Although growing evidence suggests that financial incentives for vaccination are acceptable to PEH, their impact on uptake is unknown. This study aimed to assess whether offering $50 gift cards was associated with the uptake of the first doses of COVID-19 vaccine among PEH in Los Angeles County.

          Methods

          Vaccination clinics began on March 15, 2021; the financial incentive program was implemented from September 26, 2021 to April 30, 2022. Interrupted time-series analysis with quasi-Poisson regression was used to evaluate the level and slope change in the number of weekly first doses administered. Time-varying confounders included the weekly number of clinics and the weekly number of new cases. Demographic characteristics were compared for PEH vaccinated before and after the implementation of the incentive program using chi-square tests.

          Results

          Offering financial incentives was associated with the administration of 2.5 times (95% CI=1.8, 3.1) more first doses than would have been expected without the program. Level (-0.184, 95% CI= -1.166, -0.467) and slope change (0.042, 95% CI=0.031, 0.053) were observed. Individuals who were unsheltered, aged <55 years, and identified as Black or African American accounted for a higher percentage of those vaccinated during the post-intervention period than during the pre-intervention period.

          Conclusions

          Financial incentives may be an effective tool for increasing vaccine uptake among PEH, but important ethical considerations must be made to avoid coercion of vulnerable populations.
            Cover page: Financial Incentives for COVID-19 Vaccines Among People Experiencing Homelessness
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2018)
            Alcohol dependence (ALC) is a chronic, relapsing disorder that increases the burden of chronic disease and significantly contributes to numerous premature deaths each year. Previous research suggests that chronic, heavy alcohol consumption is associated with differential DNA methylation patterns. In addition, DNA methylation levels at certain CpG sites have been correlated with age. We used an epigenetic clock to investigate the potential role of excessive alcohol consumption in epigenetic aging. We explored this question in five independent cohorts, including DNA methylation data derived from datasets from blood (n = 129, n = 329), liver (n = 92, n = 49), and postmortem prefrontal cortex (n = 46). One blood dataset and one liver tissue dataset of individuals with ALC exhibited positive age acceleration (p < 0.0001 and p = 0.0069, respectively), whereas the other blood and liver tissue datasets both exhibited trends of positive age acceleration that were not significant (p = 0.83 and p = 0.57, respectively). Prefrontal cortex tissue exhibited a trend of negative age acceleration (p = 0.19). These results suggest that excessive alcohol consumption may be associated with epigenetic aging in a tissue-specific manner and warrants further investigation using multiple tissue samples from the same individuals.
              Cover page: DNA methylation age is accelerated in alcohol dependence
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2022)

              Background

              COVID-19 vaccination is a priority for people experiencing homelessness. However, there are barriers to vaccine access driven in part by mistrust towards clinicians and healthcare. Community health workers (CHWs) and Peer Ambassadors (PAs) may be able to overcome mistrust in COVID-19 vaccine outreach. An unhoused PA program for COVID-19 vaccine outreach by CHWs was implemented in Los Angeles using a participatory academic-community partnership.

              Objective

              The purpose of this study was to evaluate CHW perspectives on an unhoused PA COVID-19 vaccine outreach program in Los Angeles.

              Design

              This study used a participatory community conference and qualitative focus groups to understand CHW perspectives on the PA program. The one-day conference was held in November 2021.

              Participants

              Of the 42 conference participants, 19 CHWs participated in focus groups for two-way knowledge exchange between CHWs and researchers.

              Approach

              Four focus groups were held during the conference, with 4-6 CHWs per group. Each group had a facilitator and two notetakers. Focus group notes were then analyzed using content analysis to derive categories of findings. CHWs reviewed the qualitative analysis to ensure that findings represented their experiences with the PA program.

              Key results

              The five categories of findings from focus groups were as follows: (1) PAs were effective liaisons to their peers to promote COVID-19 vaccines; (2) CHWs recognized the importance of establishing genuine trust and equitable working relationships within CHW/PA teams; (3) there were tradeoffs of integrating unhoused PAs into the existing CHW workflow; (4) CHWs had initial misgivings about the research process; and (5) there were lingering questions about the ethics of "exploiting" the invaluable trust unhoused PAs have with unhoused communities.

              Conclusions

              CHWs were in a unique position to empower unhoused PAs to take a leadership role in reaching their peers with COVID-19 vaccines and advocate for long-term employment and housing needs.
                Cover page: Community Health Worker Perspectives on Engaging Unhoused Peer Ambassadors for COVID-19 Vaccine Outreach in Homeless Encampments and Shelters
                • Article
                • Peer Reviewed
                UCLA Previously Published Works (2022)
                Unhoused people have higher COVID-19 mortality and lower vaccine uptake than housed community members. Understanding vaccine hesitancy among unhoused people is key for developing programs that address their unique needs. A three-round, rapid, field-based survey was conducted to describe attitudes toward COVID-19 vaccination. Round 1 assessed vaccine brand preference, round 2 assessed intention to accept a financial incentive for vaccination, and round 3 measured vaccine uptake and assessed reasons for vaccine readiness during implementation of a financial incentive program. A total of 5177 individuals were approached at COVID-19 vaccination events for unhoused people in Los Angeles County from May through November 2021. Analyses included 4949 individuals: 3636 (73.5%) unsheltered and 1313 (26.5%) sheltered. Per self-report, 2008 (40.6%) were already vaccinated, 1732 (35%) wanted to get vaccinated, 359 (7.3%) were not yet ready, and 850 (17.2%) did not want to get vaccinated. Brand preference was evenly split among participants (Moderna 31.0%, J&J 35.5%, either 33.5%, p = 0.74). Interest in a financial incentive differed between those who were not yet ready and those who did not want to get vaccinated (43.2% vs. 16.2%, p < 0.01). After implementing a financial incentive program, 97.4% of participants who indicated interest in vaccination were vaccinated that day; the financial incentive was the most cited reason for vaccine readiness (n = 731, 56%). This study demonstrated the utility of an iterative, field-based assessment for program implementation during the rapidly evolving pandemic. Personal engagement, a variety of brand choices, and financial incentives could be important for improving vaccine uptake among unhoused people.
                  Cover page: COVID-19 Vaccine Acceptability and Financial Incentives among Unhoused People in Los Angeles County: a Three-Stage Field Survey
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2022)

                  Background

                  This study aimed to evaluate the feasibility and acceptability of engaging unhoused peer ambassadors (PAs) in coronavirus disease 2019 (COVID-19) vaccination efforts to reach people experiencing unsheltered homelessness in Los Angeles County.

                  Methods

                  From August to December 2021, vaccinated PAs aged ≥18 years who could provide informed consent were recruited during vaccination events for same-day participation. Events were held at encampments, service providers (eg, housing agencies, food lines, and mobile showers), and roving locations around Los Angeles. PAs were asked to join outreach alongside community health workers and shared their experience getting vaccinated, receiving a $25 gift card for each hour they participated. Postevent surveys evaluated how many PAs enrolled and how long they participated. In October 2021, we added a preliminary effectiveness evaluation of how many additional vaccinations were attributable to PAs. Staff who enrolled the PAs estimated the number of additional people vaccinated because of talking with the PA.

                  Results

                  A total of 117 PAs were enrolled at 103 events, participating for an average of 2 hours. At events with the effectiveness evaluation, 197 additional people were vaccinated over 167 PA hours ($21.19 gift card cost per additional person vaccinated), accounting for >25% of all vaccines given at these events.

                  Discussion

                  Recruiting same-day unhoused PAs is a feasible, acceptable, and preliminarily effective technique to increase COVID-19 vaccination in unsheltered settings. The findings can inform delivery of other health services for people experiencing homelessness.
                    Cover page: Engaging Same-Day Peer Ambassadors to Increase Coronavirus Disease 2019 Vaccination Among People Experiencing Unsheltered Homelessness in Los Angeles County: A Hybrid Feasibility-Evaluation Study
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