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Open Access Publications from the University of California

Tobacco-Related Disease Research Program Funded Publications

Tobacco use remains the single most preventable cause of disease, disability, and death in the United States and in California. The Tobacco-Related Disease Research Program (TRDRP) is one of three entities that constitute California’s program to control tobacco consumption and alleviate the burden of tobacco-related disease. This effort was initiated by Proposition 99, “The Tobacco Tax and Health Protection Act of 1988” which mandated that the Department of Health Services, the Department of Education and the University of California be allocated a portion of the tobacco tax revenue collected to address issues of tobacco consumption and its consequences in the state. Enabling legislation requested that the University of California, in its role as the research arm of the state, “administer a comprehensive grant program to support research efforts related to the prevention, causes, and treatment of tobacco-related diseases” and that “ all qualified investigators, regardless of institutional affiliation, shall have equal access and opportunity to compete for the funds.”

The TRDRP is administered by the University of California and is a program of the Research Grants Program Office (RGPO), Office of Research and Graduate Studies at the University of California, Office of the President.

Cover page of Secondhand smoke exposure at home and school absenteeism among children in the United States: national estimates of attributable missed school days

Secondhand smoke exposure at home and school absenteeism among children in the United States: national estimates of attributable missed school days

(2026)

Objective: The number of missed school days attributable to secondhand smoke (SHS) exposure at home among U.S. children has not been quantified. We estimated the association between SHS exposure at home and school absenteeism and derived national estimates of SHS-attributable missed school days. Methods: We analyzed data from the 2016-2024 National Survey of Children's Health for U.S. children aged 6-11 years. Propensity score weighting and two-part models were used to estimate the association between SHS exposure at home and school absenteeism. National estimates of SHS-attributable missed school days were derived by combining model-based attributable fractions with national public school enrollment data. Results: SHS exposure at home was associated with both a higher likelihood of missing school and a greater number of missed school days among children with any absence. In 2024, an estimated 266,008 (95% CI: 139,627, 392,390) missed school days were attributable to SHS exposure at home nationwide, corresponding to 0.95 additional missed school days per exposed child (95% CI: 0.56, 1.34). Conclusions: This study provides the first national estimates of SHS-attributable missed school days among U.S. children. These findings suggest that reducing children's SHS exposure may further improve school attendance and promote more efficient use of educational resources.

Cover page of Quantifying the Mediation Effect of Disease Stage on Racial Disparities in Head and Neck Cancer Survival

Quantifying the Mediation Effect of Disease Stage on Racial Disparities in Head and Neck Cancer Survival

(2026)

There are significant racial and ethnic disparities in head and neck cancer (HNC) survival. Disparities in cancer stage appear to account for some of the disparities in survival. However, the proportion of the survival disparities mediated by cancer stage is unclear. This study aimed to quantify the mediation effects of stage at diagnosis on racial/ethnic disparities in HNC survival using data from the California Cancer Registry. We found that T3-4 disease accounted for 36.3% (95% CI 15.6% to 57.0%) of the association between Black (versus White) and worse OS, and for 44.2% (95% CI 10.9% to 77.4%) of the association between Black (versus White) and worse DSS. This suggests that interventions aimed at improving access to care and early detection of malignancies may have highest impact in reducing racial/ethnic disparities in HNC survival. Future studies are needed to further understand factors that drive racial disparities in HNC stage at diagnosis, and to inform the development of intervention strategies to address these disparities.

Formation of Tobacco-Specific Nitrosamines from the Atmospheric Aging of Nicotine in E-Cigarette Aerosols

(2026)

Abstract The atmospheric aging of nicotine-containing e-cigarette aerosols in the presence of nitrogen dioxide (NO2) and ozone (O3) may significantly alter their chemical composition and toxicological properties. However, the chemical transformation of nicotine within the complex e-cigarette aerosol matrix and its interaction with atmospheric oxidants remain largely uncharacterized. This study investigated the formation of tobacco-specific nitrosamines (TSNAs) from the aging of nicotine in e-cigarette aerosols exposed to NO2 and O3. We observed that NO2 facilitates the formation of N′-nitrosonornicotine (NNN) through direct nitrosation pathways, whereas O3 alone does not significantly contribute to TSNA production. In contrast, the presence of both oxidants enhanced the formation of nicotine-derived nitrosamine ketone (NNK), suggesting that oxidative transformation of nicotine plays an important role in its formation. FIGAERO-ToF-CIMS measurements identified several nicotine transformation products in aged e-cigarette aerosols that are not present in the fresh emissions, indicating chemical transformation during aging. Furthermore, long-amplicon qPCR analysis revealed that BEAS-2B cells exposed to aged aerosols experienced increased DNA damage, demonstrating enhanced genotoxic potential relative to their fresh counterparts. These findings indicate that atmospheric aging can convert nicotine into carcinogenic TSNAs and other reactive intermediates, increasing the potential health risks associated with secondhand and thirdhand vaping exposure. This work highlights the importance of considering chemically aged aerosols when evaluating the toxicity of e-cigarette emissions.

Day-level associations of nicotine and cannabis vaping and co-vaping with sleep duration and quality among young adults: A smartphone-based daily diary study

(2026)

OBJECTIVE: Nicotine and cannabis vaping are increasingly prevalent among young adults, and aiding sleep is a common reason for cannabis use. This study examined relationships between daily nicotine/cannabis vaping patterns and sleep. METHODS: From 2023 to 2024, 111 California young adults (aged 18-29; mean age = 23.9±3.0; 64% female; 31.5% non-Hispanic White) who vaped nicotine/cannabis ≥20 days/month completed 30 consecutive days of smartphone-based surveys. Self-reported sleep outcomes included 1) sleep duration (inadequate <7 versus adequate ≥7 hours) and 2) sleep quality (0=terrible to 10=excellent). Daily vaping patterns were non-vaping, nicotine-only vaping, cannabis-only vaping, or same-day co-vaping. Generalized mixed-effects models examined day-level associations between vaping patterns and sleep that night, adjusting for other substance use and baseline covariates. RESULTS: Of 2147 daily assessments, 51.7% reported inadequate sleep; mean sleep quality was 6.1±2.1. Nicotine-only vaping was most frequently reported (42.5% of the days), followed by same-day co-vaping (32.1%), non-vaping (16.1%), and cannabis-only vaping (9.3%). Nicotine-only vaping days had greater odds of inadequate sleep versus non-vaping (OR=1.40, 95%CI: 1.01-1.94) and versus cannabis-only days (1.93 [1.31-2.85]). Days with same-day co-vaping had greater odds of inadequate sleep compared with cannabis-only vaping (1.50 [1.01-2.23]). Associations between sleep quality and daily vaping patterns were not statistically significant. CONCLUSIONS: Nicotine vaping was associated with inadequate sleep duration compared to non-vaping or cannabis-only vaping. Despite perceptions of cannabis as a sleep aid, cannabis vaping did not improve sleep quality compared to non-vaping. These findings highlight the need for educational efforts or interventions addressing sleep health among young adults who vape nicotine and/or cannabis.

Aryl-hydrocarbon receptor in smooth muscle cells protects against dioxin-induced atherosclerosis

(2026)

BackgroundDioxins are persistent environmental pollutants found in industrial emissions, tobacco smoke, and air pollution. Chronic exposure is associated with cardiovascular disease, but how dioxins act within the vessel wall to promote atherosclerosis remains unclear. We aimed to determine how dioxin exposure alters vascular smooth muscle cell behavior and whether smooth muscle cell aryl hydrocarbon receptor signaling modifies plaque progression.MethodsWe studied atherosclerotic mouse models exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin and complementary cultures of human coronary artery smooth muscle cells. We used single-cell gene-expression profiling, single-cell chromatin-accessibility profiling, smooth muscle cell lineage tracing, histology, cell migration and proliferation assays, and chromatin binding analysis.ResultsHere we show that dioxin exposure accelerates atherosclerosis, increases plaque size, promotes early smooth muscle cell phenotypic transitions, and enhances inflammatory cell recruitment. Modulated smooth muscle cells emerge as the most transcriptionally responsive vascular cell type to dioxin and important inflammatory mediators within plaques. Dioxin-induced gene programs overlap with tobacco-associated responses and are enriched for migration, inflammation, and cell-death pathways. Dioxin also increases chromatin accessibility at vascular remodeling and immune activation genes and reduces genomic binding of TCF21, a regulator of smooth muscle cell stability. Loss of aryl hydrocarbon receptor signaling specifically in smooth muscle cells worsens dioxin-induced plaque growth, oxidative stress, and loss of smooth muscle cell-derived fibrous cap cells.ConclusionsThese findings identify smooth muscle cell reprogramming as a mechanism by which dioxin promotes atherosclerosis and vascular inflammation. They also reveal that endogenous smooth muscle cell aryl hydrocarbon receptor signaling protects against oxidative stress and helps preserve plaque-stabilizing fibrous cap structure.

Cover page of Reclaiming Public Parks and Public Health: Community-Led Safe Passages and Physical Activity in South Los Angeles, California.

Reclaiming Public Parks and Public Health: Community-Led Safe Passages and Physical Activity in South Los Angeles, California.

(2026)

BACKGROUND: Safe passage interventions aim to enhance public safety and improve access to community resources, including public parks, in underserved communities. However, no studies have directly compared community- and police-led safety interventions with respect to park-based moderate to vigorous physical activity (MVPA). To address this gap, we compared associations between Community-led Safe Passage Services (SPS) and the Los Angeles Police Department Community Safety Partnership (CSP) program with MVPA in South Los Angeles public parks. METHODS: We conducted structured observations of 3997 park users across 8 SPS and 9 CSP parks in South Los Angeles using the System for Observing Play and Recreation in Communities and the Physical Activity Resource Assessment. We applied t tests, analysis of variance, and hierarchical linear models to examine MVPA across park intervention types. RESULTS: Overall, MVPA was higher in SPS parks (P < .001). Black, male, teen, and adult park users exhibited significantly higher MVPA in SPS parks (P < .001). A hierarchical linear model controlling for sex, age, race, and park conditions indicated that Black park users were significantly less physically active in CSP parks (P = .05). Conversely, Black park users had significantly higher MVPA in SPS parks (P = .034). Intervention type was a stronger predictor of MVPA than park features and amenities, whereas incivilities were negatively associated with MVPA (P < .001). CONCLUSIONS: Community-led safety interventions may promote physical activity among Black park users. These findings suggest that community-led public park safety models are a promising approach for advancing health equity.

Cannabis Use Among Veterans Versus Non-Veterans in the USA, 2016–2023: A Cross-Sectional Analysis

(2026)

BackgroundVeterans have a unique health profile and risk for substance use, but few studies compare cannabis use patterns among US military Veterans and non-veteran civilians.ObjectiveTo examine differences in age-specific patterns, modes of use, and sociodemographic correlates of cannabis use between Veterans and non-Veterans.Design, Participants, MeasuresWe conducted a cross-sectional analysis of Behavioral Risk Factor Surveillance System data from 2016 to 2023. The analytic sample included 907,136 adults aged 18 to 80 years with complete data on self-reported veteran status and cannabis use. Primary outcomes were past 30-day cannabis use (yes/no), frequency of use in the past 30 days, and inhalational vs. non-inhalational use methods. Multivariable logistic regressions were used to assess sociodemographic and behavioral correlates of cannabis use. Analyses were conducted from March to June 2025.ResultsAmong participants, 114,193 (12.6%) were Veterans. Although overall cannabis use was lower among Veterans than non-Veterans, age-specific patterns differed. Veterans aged 50–64 years were 43% (95% CI, 28–59%) more likely to report cannabis use than non-Veterans, and those aged 65–80 were 22% (95% CI, 9–37%) more likely. Older Veterans also reported more frequent cannabis use in the past 30 days (mean 18.4 versus 15.8 days among those aged 50–64 years; 17.3 vs. 14.5 days among those aged 65–80 years). Inhalational use was more common among Veterans than non-Veterans (90.0%; 95% CI, 87.8–91.9% vs. 83.7%; 95% CI, 82.5–84.9%). Some correlates of cannabis use were shared across groups; however, educational attainment was differentially associated with cannabis use by veteran status.ConclusionsVeterans aged ≥ 50 years were more likely to report cannabis use and used it more frequently than their non-veteran peers, suggesting they may need tailored interventions to address cannabis use.

Associations of Cannabis and Tobacco Use With Suicide Attempt, Suicide Death, and Overdose Death Among Veterans Prescribed Opioid Analgesics

(2026)

INTRODUCTION: Little is known whether cannabis and tobacco use are indicators of suicide-related risks. This longitudinal study examined the associations of cannabis and tobacco use with risks of suicide attempt/death and overdose death over a 2-year follow-up in a cohort of veterans prescribed opioids. METHODS: This study analyzed data in 2024 using a national cohort of 923,291 veterans receiving opioid analgesics in Veterans Health Administration clinics collected during 2014-2019. Cannabis and tobacco use were assessed at cohort entry. Outcomes (suicide attempts, suicide death, overdose death) were obtained at follow-up through 2021. Cause-specific hazard models were used to examine the associations of cannabis and tobacco use with each outcome, adjusting for well-established risk factors for suicide/overdose (e.g., substance use disorders, mental health, sociodemographics). RESULTS: At baseline, 5.4% of the cohort used cannabis, and 39.4% used tobacco. At the end of follow-up (median follow-up time of 6.7-6.8 years), 2.2% of the sample had attempted suicide, 0.4% had died by suicide, and 0.5% had died by overdose. In adjusted models, cannabis use was associated with a higher rate of suicide attempt (hazard ratio=1.11, 95% CI=1.06, 1.15). Current use of tobacco at baseline (versus never use) was associated with a higher rate of suicide attempts (hazard ratio=1.18, 95% CI=1.13, 1.22), suicide deaths (hazard ratio=1.19, 95% CI=1.07, 1.32), and overdose deaths (hazard ratio=1.67, 95% CI=1.51, 1.83). CONCLUSIONS: Cannabis and tobacco use were associated with suicide attempts/deaths and overdose deaths among veterans prescribed opioid analgesics, underscoring a need for monitoring patients who use tobacco and cannabis in this population.

A systematic review investigating policy design and implementation of US state and local policy to restrict the sale of flavored tobacco products

(2026)

INTRODUCTION: State and local jurisdictions in the United States are increasingly adopting flavored tobacco sales restrictions (FTSRs) to mitigate tobacco initiation and use. Policy implementation is highly understudied yet can impact policy effectiveness. This review examines existing literature on state and local FTSR policy design and implementation in the United States. METHODS: We systematically searched for PubMed articles published by December 31, 2024 which were: original research articles in English focused on a US state or local FTSR that reported at least one policy implementation outcome measure. We excluded articles that were systematic reviews or reported on federal or non-FTSR policy. Guided by policy and implementation science frameworks, we developed a data extraction template to report: policy design elements, study characteristics, and implementation measures (ie, inputs, activities, outcomes). RESULTS: Of 1595 articles identified, 30 were retained for review. Most evaluated local FTSRs, and eight evaluated a statewide policy. Pre-post test and cross-sectional study designs were the most common. Frequently reported implementation outcomes were acceptability, appropriateness, feasibility, and fidelity/compliance. Studies with pre-post test designs and comparison groups showed significantly increased fidelity/compliance (ie, reduced availability of restricted products) in FTSR jurisdictions. A majority (56.7%) detailed an implementation input for infrastructure (eg, resources) or activity (eg, outreach). Few described enforcement-related mechanisms. CONCLUSIONS: Key gaps exist in policy implementation articles on state and local FTSRs in the United States, including infrequent reporting of enforcement agencies and penalties which may impact implementation. Additional mixed-methods research is needed to compare FTSR implementation across jurisdictions with varying policy designs. IMPLICATIONS: Results contribute to our understanding of FTSR policy design, evaluation, and areas needed for intervention to strengthen implementation. Strategies to support compliance include guidance and criteria to identify targeted products for retailers and enforcement agents. Research gaps include a lack of information on penalty structures and data from enforcement agents or on violations, which are missed opportunities to evaluate components that can impact implementation and effectiveness.