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Open Access Publications from the University of California

Scholarly Works (82 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2017)

Objectives

Twenty-eight states in the U.S have legalized medical marijuana, yet its impacts on severe health consequences such as hospitalizations remain unknown. Meanwhile, the prevalence of opioid pain reliever (OPR) use and outcomes has increased dramatically. Recent studies suggested unintended impacts of legalizing medical marijuana on OPR, but the evidence is still limited. This study examined the associations between state medical marijuana policies and hospitalizations related to marijuana and OPR.

Methods

State-level annual administrative records of hospital discharges during 1997-2014 were obtained from the State Inpatient Databases (SID). The outcome variables were rates of hospitalizations involving marijuana dependence or abuse, opioid dependence or abuse, and OPR overdose in 1000 discharges. Linear time-series regressions were used to assess the associations of implementing medical marijuana policies to hospitalizations, controlling for other marijuana- and OPR-related policies, socioeconomic factors, and state and year fixed effects.

Results

Hospitalizations related to marijuana and OPR increased sharply by 300% on average in all states. Medical marijuana legalization was associated with 23% (p=0.008) and 13% (p=0.025) reductions in hospitalizations related to opioid dependence or abuse and OPR overdose, respectively; lagged effects were observed after policy implementation. The operation of medical marijuana dispensaries had no independent impacts on OPR-related hospitalizations. Medical marijuana polices had no associations with marijuana-related hospitalizations.

Conclusion

Medical marijuana policies were significantly associated with reduced OPR-related hospitalizations but had no associations with marijuana-related hospitalizations. Given the epidemic of problematic use of OPR, future investigation is needed to explore the causal pathways of these findings.
    Cover page: Medical marijuana policies and hospitalizations related to marijuana and opioid pain reliever
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2021)

    Background and aims

    Different cannabis administration methods have differential impacts on health. This study aimed to describe administration methods among cannabis users in the United States categorized by (1) use purpose and (2) state legalization status.

    Design

    Cross-sectional, probability-based online survey in 2020.

    Setting

    All 50 states and Washington DC in the United States.

    Participants

    A total of 21 903 adults (18+) were recruited from a probability-based online panel to provide nationally representative estimates.

    Methods

    Eleven administration methods were grouped into combustion, vaporization, ingestion and topicals. Weighted prevalence was reported among (1) medical-only, recreational-only and dual-purpose users based on self-reported purposes and (2) users in states that legalized both recreational and medical cannabis (RCL states), legalized medical cannabis only and did not legalize cannabis.

    Findings

    Among past-year users, the proportions of medical-only, recreational-only and dual-purpose users were 25.55, 43.81 and 30.64%, respectively. The most common primary methods were combustion (42.08%) and topicals (28.65%) for medical purposes and combustion (72.07%) and ingestion (15.05%) for recreational purposes. Dual-purpose users were more likely to report combustion and vaporization but less likely to report ingestion and topicals as primary methods for medical use than medical-only users (P < 0.001) and more likely to report combustion and topicals but less likely to report ingestion as primary methods for recreational use than recreational-only users (P < 0.041). A higher proportion of dual-purpose users (82.82%) used more than one method than medical-only (40.52%) and recreational-only users (63.91%) (P < 0.001). For both medical and recreational purposes, RCL states had the lowest rate of combustion and the highest rates of ingestion and topicals reported as primary methods (P < 0.033). The rate of using more than one administration method did not differ across states (P > 0.05).

    Conclusion

    Cannabis users whose purposes are medical, recreational or both tend to differ in their selected administration methods.
      Cover page: Heterogeneities in administration methods among cannabis users by use purpose and state legalization status: findings from a nationally representative survey in the United States, 2020
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2019)
      Background: Evidence is emerging on how state-wide marijuana legalization and increased supply of DATA-2000 waivered providers may be associated with outcomes related to opioids. It is unknown whether such associations remain at the neighborhood level. Objectives: This study examined the associations of neighborhood availability of marijuana dispensaries and DATA-2000 waivered providers with opioid-related hospital stays. Methods: Discharge-level records of inpatient (N = 264,013) and observation stays (N = 12,621) were obtained from the Washington Comprehensive Hospital Abstract Reporting System from January through June 2016. Outcomes were indicators for inpatient stays related to opioid use disorder (OUD), inpatient stays related to opioid overdose, and observation stays related to OUD. Primary predictors were the density of marijuana dispensaries and DATA-2000 waivered providers at the zip code level. Multilevel logistic regressions with random intercepts were used to examine the cross-sectional associations, controlling for other patient and neighborhood characteristics. Results: Patients living in neighborhoods with one more recreational marijuana dispensaries per square mile were more likely (OR = 1.54, p = .017) to be diagnosed with OUD in inpatient stays. Living in neighborhoods with increased density of medical marijuana dispensaries or DATA-2000 waivered providers was not associated with being diagnosed with OUD or opioid overdose in inpatient or observation stays. Conclusions: Recreational and medical marijuana dispensaries were differentially associated with opioid-related hospital stays. Further investigations are warranted to explore the causal pathways of the findings.
        Cover page: The Associations of Neighborhood Availability of Marijuana Dispensaries and DATA-2000 Waivered Providers with Hospital Stays Related to Opioids
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2019)

        Background and aims

        In the US, benzodiazepine overdose deaths increased at an alarming rate in the past two decades. Benzodiazepines were also the most common drugs involved in prescription opioid overdose deaths. Benzodiazepine prescribing has been monitored by Prescription Drug Monitoring Programs (PDMPs), but little was known about whether PDMPs reduced drug overdose deaths involving benzodiazepines.

        Design and methods

        This study used a difference-in-difference design with state-quarter aggregate data on drug overdose deaths. The primary data source was Mortality Multiple Cause Files in 1999-2016. Three age-adjusted rates of drug overdose deaths were examined, including those involving benzodiazepines, those involving prescription opioids, and those involving both benzodiazepines and prescription opioids. The policy variables included PDMP data access for benzodiazepines and mandatory use of PDMP data for benzodiazepines. Linear multivariable regressions were used to assess the associations of PDMP policies specific to benzodiazepines with drug overdose death rates, controlling for other state-level policy and socioeconomic factors, state and time fixed effects, and state-specific time trends.

        Results

        No significant associations were found between PDMP data access for benzodiazepines and changes in drug overdose death rates involving benzodiazepines and/or prescription opioids. Similarly, no significant associations were found between mandatory use of PDMP data for benzodiazepines and changes in drug overdose death outcomes.

        Discussion and conclusions

        This study suggested no evidence that PDMP policies specific to benzodiazepines were associated with reduction in benzodiazepine overdose death rates. Future research is warranted to examine detailed features of PDMPs and continuously monitor the impacts of PDMP policies on benzodiazepine-related consequences.
          Cover page: Prescription drug monitoring programs and drug overdose deaths involving benzodiazepines and prescription opioids
          • Article
          • Peer Reviewed
          UC San Diego Previously Published Works (2020)

          Objectives

          States in the US are controlling opioid prescribing to combat the opioid epidemic. Prescription Drug Monitoring Programs (PDMPs) were widely adopted, whereas less attention was given to pain clinic laws. This study examined the associations of mandatory use of PDMPs and pain clinic laws with prescription opioid exposures.

          Methods

          State-level quarterly prescription opioid exposures reported to the National Poison Data System during 2010-2017 were analyzed. The primary outcome was age-adjusted rates of prescription opioid exposures per 1,000,000 population. The primary policy variables included the implementation of mandatory use of PDMPs alone, the implementation of pain clinic laws alone, and the implementation of both mandatory use of PDMPs and pain clinic laws. Linear regressions were used to examine the associations, controlling for other opioid policies, marijuana policies, socioeconomic factors, state fixed effects, time fixed effects, and state-specific time trends.

          Results

          Requiring mandatory use of PDMPs alone was not associated with significant changes in prescription opioid exposures. The implementation of pain clinic laws with or without concurrent mandatory use of PDMPs was associated with 5 fewer prescription opioid exposures per 1,000,000 population or a 9 % reduction compared to the pre-policy period (p < 0.01). Further analysis revealed that the reduction associated with pain clinic laws was pronounced in exposures reported by healthcare facilities.

          Conclusions

          This multi-state study provided new evidence that the implementation of pain clinic laws was associated with a significant reduction in prescription opioid exposures. Pain clinic laws may deserve further evaluation and consideration.
            Cover page: The association between pain clinic laws and prescription opioid exposures: New evidence from multi-state comparisons
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2020)

            Background and aims

            Recreational cannabis has been legalized in 11 states and District of Columbia (DC) in the United States. Among these, 10 states further permitted retail sale to provide a legal supply to adults. This study examined the associations of cannabis exposures with recreational cannabis legalization and commercialization.

            Design

            Secondary data analysis of state-quarter level cannabis exposures during 2010-17 in the United States. Linear regressions with a difference-in-differences design were used to compare pre- and post-legalization trends in states that legalized recreational cannabis to contemporaneous trends in states that did not legalize recreational cannabis.

            Setting

            United States, including all 50 states and DC.

            Cases

            Cannabis exposures reported to the US National Poison Data System.

            Measurements

            The primary outcome was state age-adjusted cannabis exposures reported to the US National Poison Data System per 1 000 000 population per quarter. The two policy variables of interest included (1) the enactment of recreational cannabis legalization (i.e. removing penalties for adults' possession of cannabis in a small amount for recreational use) and (2) the initiation of recreational cannabis commercialization (i.e. providing a legal supply of cannabis to adults through licensed dispensaries).

            Findings

            The association between a state's enactment of recreational cannabis legalization and its changes in cannabis exposures was statistically non-significant overall. After controlling for recreational cannabis legalization, however, the initiation of recreational cannabis commercialization was associated with 5.06-5.80 more exposures per 1 000 000 population per quarter (67-77% increase relative to the pre-legalization average), depending on the composition of comparison states. The increase associated with commercialization was higher among minors than adults (7.97-9.53 versus 3.83-4.21 more exposures), higher among males than females (6.16-7.56 versus 3.76-3.91 more exposures) and higher among exposures with medical consequences than those without medical consequences (4.09-4.79 versus 0.97-1.01 more exposures).

            Conclusion

            An increase in cannabis exposures reported to the US National Poison Data System was observed following recreational cannabis commercialization in the United States.
              Cover page: The association between recreational cannabis commercialization and cannabis exposures reported to the US National Poison Data System
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2014)
              Both biological and social sciences have identified contributing factors to human health. However, health outcomes are unlikely to equal a simple sum of these identified factors. This article makes an attempt to put together the information, methods, and technologies that relate to health outcomes from biological, behavioral, and social disciplines. Much of this information was obtained by controlling for the variations of the factors in 'other' disciplines. For example, genetic factors were controlled for in identifying the behavioral determinants of health. Looking forward, better understandings of health outcomes may require exploiting the interactions of health determinants that were identified from different disciplines. We propose the concept of 'systems health' studies, which take health outcomes as the outputs of a system, where the inputs and their interactions from multiple disciplines are considered.
                Cover page: From genomes to societies: a holistic view of determinants of human health.
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (2022)
                The uptake rate of COVID-19 vaccines among children remains low in the U.S. This study aims to 1) identify sociodemographic and behavioral factors influencing parental refusal of vaccinating children, and 2) quantify the relative importance of vaccine characteristics in parental hesitancy of vaccinating children. An online survey was conducted from October to November 2021 among a probability-based, representative sample of 1456 parents with children under age 18. The survey included a discrete choice experiment asking parents to choose between two hypothetical COVID-19 vaccine alternatives with varying levels of characteristics in 10 hypothetical scenarios. Logistic regressions were used to estimate parental refusal (refused to choose any vaccine alternatives in all hypothetical scenarios) and random parameter logit regressions were used to estimate parental hesitancy (choice of vaccine alternatives depended on vaccine characteristics) of vaccinating children. About 20% parents refused to vaccinate children. The refusal is predicted by parents' sociodemographic characteristics, political orientation, vaccination status, and parents' and children's previous exposure with COVID-19. Among parents who were willing to consider vaccinating children, the most important vaccine characteristics are risk of severe side effects (31.2% relative importance) and effectiveness (30.7%), followed by protection duration (22.6%), local coverage (9.4%), and hospitalization rate of unvaccinated children (6.1%). Our findings imply that policymakers and public health professionals could develop outreach programs at community level to encourage specific subgroups and focus on vaccination depoliticization. Effectively communicating the low risk of severe side effects and high effectiveness of the vaccines may relieve some of the parental hesitancy.
                  Cover page: Parental refusal and hesitancy of vaccinating children against COVID-19: Findings from a nationally representative sample of parents in the U.S.
                  • Thesis
                  • Peer Reviewed
                  UC Davis Electronic Theses and Dissertations (2022)

                  Soil penetration activities, such as site investigation, pile driving and tunneling, are ubiquitous and fundamentally important in civil engineering. These penetration activities are energy-intensive and responsible for considerable environmental disruption due to the usage of large equipment required to provide reaction force. Bio-inspired geotechnics has received significant attention in recent years due to the growing need for making construction processes more sustainable. This research investigates the anchor-tip strategy inspired by earth and marine worms, razor clams, and caecilians and the circumnutation strategy inspired by plant roots. Throughout this dissertation, it is shown that using the bio-inspired strategies can facilitate soil penetration by reducing the mobilized penetration resistance and generating anchorage reaction forces.Discrete element modeling (DEM) is used to simulate the bio-inspired soil penetration process of an in-situ testing probe in granular soils. Different soil conditions are examined in the DEM simulations, including soil density and magnitude of overburden stress. Simulations were performed on specimens confined to constant stress levels using servo-controlled algorithms to model deep penetration conditions. Simulations were also performed on unconfined soil specimens under gravity to model shallow soil conditions. The simulated anchor-tip strategy consists of radially expanding of a probe section or sections (i.e. anchor(s)) and subsequently displacement of the probe tip to deeper locations. The global and meso-scale responses of the probe-soil system are analyzed to shed light on the working mechanisms of this strategy. Specifically, the expanded anchor serves as a integrated anchorage system to provide the reaction force needed for penetration. The anchor expansion leads to reduction in tip resistance by altering stress states around the tip. The effects of a number of aspects of the anchor and tip geometry, as well as of soil depth, are explored. The effects of soil density on the anchor-tip strategy are also highlighted. Due to the complexity of anchor-tip strategy, three simulation strategies employed to control the probe’s motions: displacement-controlled algorithm, velocity controlled algorithm with force limits and force-controlled algorithm. Among these three strategies, the first one is the most simplified one while the last one best approximated the motion used by the model organisms. The simulated circumnutation inspired motion (CIM) consists of helical movements of the probe tip accompanied by downward penetration of the entire probe. The probe forces, torque, mechanical work and particle contact orientations are analyzed and discussed. The results indicate that CIM leads to a decrease of penetration resistance by altering the contact orientations near the tip from the vertical to the horizontal direction. However, this reduction in penetration resistance comes at a cost of increased torque and in most conditions an increase in rotational work. A comparison of the CIM and rotational penetration (RP) strategies shows that the CIM mobilizes smaller penetration forces and requires less total mechanical work to penetrate the same distance as the RP. The effects of the CIM velocities and probe geometry are also examined. The understanding of the probe-soil interactions during the bio-inspired penetration processes lays the foundation for the development of innovative soil penetration tools and techniques to increase the efficiency of construction activities. For example, studies on bio-inspired probes can guide the design of future lightweight penetration devices. Such probes could reduce the energy consumption during transport and the challenges associated with limited accessibility in certain sites, such as congested urban areas and outer space bodies. These studies show that by learning from nature, more efficient solutions can be developed for geotechnical engineering applications.

                    Cover page: Discrete Element Modeling of Bio-Inspired Soil Penetration Processes for In-Situ Testing Probes
                    • Article
                    • Peer Reviewed
                    Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 45 (2023)
                    Current theories suggest that linguistic relativity and language embodiment are two sides of the same coin and that language embodiment and “linguistic shortcut” are two alternative types of semantic processing. It can therefore be deduced that deep embodied simulation of linguistic labels may facilitate the corresponding linguistic relativity effect more than shallow linguistic-shortcut processing does. However, this theoretical deduction has not been tested empirically. Here, participants used two newly-trained labels of verb (in)transitivity in sentence contexts that were either simulated in a deep, embodied manner (visual imagery group) or processed via shallow linguistic-shortcut (linguistic associate group). Subsequently, the former group were more likely to categorize motion events based on motion transitivity than the latter group. We thus expanded the moderators of linguistic relativity to the types of semantic access. The findings are discussed in light of the relativist, the universalist, and the sociocultural view on language-cognition relationship.
                      Cover page: Training-Induced Linguistic Relativity and Embodied ProcessingCreative Commons 'BY' version 4.0 license
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