Environmental health

Permanent URI for this collectionhttps://digital.lib.washington.edu/handle/1773/4917

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Investigating the implications of oral microplastic exposure within the context of the gut-brain axis
(2026-04-20) Kim, Kyle Joohyung; Cui, Julia JYC
Microplastics are emerging environmental contaminants due to increasing global plastic production and waste. Microplastics, defined as plastic particles less than 5 mm in diameter, are formed through degradation of larger plastics via sunlight, weathering, and microbes. These plastic compounds are widely detected in water, soil, food, as well as human stool and blood. Recent studies have found microplastic particles in organ systems throughout the human body, including bio-compartments associated with the developing fetus, highlighting both the ubiquitous nature of microplastic bioaccumulation as well as the immediacy of public health concern regarding environmental microplastic contamination. Although detection and environmental fate of microplastic particles is important for elucidating the environmental fate and transport of microplastic particles, little is known regarding oral microplastic exposure and its implications within the gut-brain axis. The gut microbiome, often referred to as our second genome, is important in human health and is the primary point of contact for orally ingested microplastics. The gut environment and its associated gut microbiome are known to influence the nutrient absorption and gut barrier function which both directly and indirectly regulates the circulatory metabolome and in turn other organ systems around the body such as the brain. Apolipoprotein-E (APOE) is an important lipid shuttling protein that is implicated in progressive neurodegenerative disorders, particularly in homozygous APOE4 allele carriers. APOE4 genotype is also known to influence xenobiotic exposure outcomes and to differentially impact the host gut microbiome and gut environment. Therefor the goal of this dissertation thesis is to strategically investigate the impact of microplastic exposure to the gut microbial composition, associated metabolome, and immunological CNS endpoints of interest with the addition of host genetics to further elucidate potential gene-environment interactions. My central hypothesis is that microplastic particles will induce gut dysbiosis, disrupt the gut microbiome associated metabolome, and impact the gut-brain axis. Microplastic induced changes to the gut microbiome and associated metabolome along with accumulation of microplastic particles may lead to a weakened gut barrier and thus causing the host to exhibit leaky gut physiology. The leaky gut barrier may introduce bacterial biproducts, metabolites, and other xenobiotics that may induce tissue damage, increased inflammatory cytokines, and a decrease in neuroprotective microbial metabolites. Second, these harmful substances may be more bioavailable to the brain, in the brain this can cause increased inflammation, oxidative stress, and cell death (molecular level). I have shown that oral microplastic exposure differentially regulates the gut microbial composition and associated serum metabolism in a dose and sex dependent manner. Additionally, I observed that in the presence of humanized APOE3/E4 genotype, OMP exposure significantly regulated more microbial taxa and serum associated metabolic pathways within APOE4 male and female mice, providing evidence of host gene modulation of microplastic associated implications within the gut micro-environment and associated serum metabolome.
Evaluating Legionella Risk Reduction Strategies in a Large Healthcare Setting: An Integrated Forward and Reverse QMRA Approach
(2026-04-20) Aberra, Abebe G; Meschke, John Scott
Legionella pneumophila is a leading cause of drinking water–associated outbreaks in the United States and presents a significant risk in healthcare facilities where complex plumbing systems and immunocompromised patient populations increase susceptibility to infection. Although water management programs and secondary disinfection systems are widely implemented, translating environmental monitoring data into meaningful health risk estimates remains challenging. This study evaluates Legionella risks at the University of Washington Medical Center (UWMC) Montlake Campus using an integrated Quantitative Microbial Risk Assessment (QMRA) framework. Environmental surveillance data collected between 2018 and 2021 from two major hospital buildings—Cascade Tower and Pacific Tower—were analyzed to characterize the occurrence and distribution of Legionella within the facility’s water systems. Forward QMRA models were applied to estimate infection risks associated with exposure to aerosolized water from showers and handwashing sinks, incorporating measured Legionella concentrations, exposure scenarios, and established dose–response relationships. In addition, a reverse QMRA approach was used to assess fixture-specific infection risks and determine the microbial concentrations corresponding to established health risk benchmarks. This analysis enabled comparison of potential infection risks associated with different fixtures and helped identify areas where targeted interventions may be most effective. The integrated QMRA framework provides a practical approach for translating environmental monitoring data into quantitative health risk estimates and supports evidence-based decision-making for Legionella management in complex healthcare water systems.
The Effects of Water Storage and Meteorological Conditions on Enteric Infections from a Matched-Control Trial in Beira, Mozambique
(2026-02-05) Kann, Rebecca Shields; Levy, Karen
The provision of community-level piped drinking water infrastructure has the potential to reduce the burden of enteric diseases, including diarrhea, in rapidly growing urban centers. However, water intermittency and water storage practices, as well as impacts of meteorological conditions, may interfere with the progress made by drinking water interventions. Results from the PAASIM study, a matched-control trial assessing a piped water supply intervention in Beira, Mozambique, showed that provision of upgraded piped water infrastructure led to a reduction in water contamination and improvement in overall access to the water supply, but mixed evidence of health benefits from the drinking water supply upgrades. In this dissertation, I assessed the impact of water storage practices and meteorological conditions on enteric infection prevalence and the effectiveness of the PAASIM drinking water intervention. In Aim 1, I evaluated the impact of water contamination, at both the point of collection (PoC) and in water storage containers, on enteric pathogen infections using a causal mediation analysis approach. I found that households where contamination was detected in their PoC water had a 32% higher prevalence of stored water contamination and that both PoC and stored water contamination were associated with a higher prevalence of children’s enteric pathogen infections for some key pathogens of interest. Findings from Aim 1 demonstrate that reducing PoC water contamination and addressing water storage practices are important for mitigating waterborne disease risk in urban areas with piped water systems. In Aim 2, I assessed the variation in enteric infection prevalence across seasons and meteorological conditions. I found that enteric infections, particularly protozoal infections and co-infections, varied depending on seasonal conditions and rainfall events. Results from Aim 2 highlight the need to consider seasonal variation in environmental conditions and human behaviors in efforts to reduce the burden of enteric disease. In Aim 3, I assessed the impact of seasonality and meteorological conditions on the effectiveness of the PAASIM intervention for reducing enteric pathogen infections. I showed that season did not impact the effectiveness of the piped water intervention, but that it was more protective for several key enteric infections of interest following heavy rainfall events. Results from Aim 3 highlight the potential benefit of piped water interventions for providing resilience to seasonal changes in environmental conditions, as well as some additional protection following heavy rainfall events. Piped water infrastructure in urban settings may help mitigate health risks associated with extreme weather events and provide robust effectiveness in the presence of seasonal variation in enteric disease. However, water intermittency and water storage practice have the potential to impede the progress made by piped water interventions. Investments in urban settings should continue to prioritize providing robust, community-level piped water infrastructure to support growing populations but should also invest in strategies to reduce water intermittency and the need for water storage. Results from these analyses may be valuable for developing more resilient drinking water intervention strategies that can accommodate rapidly growing urban populations.
Investigating the metabolic and immunological alterations of the liver from early life environmental toxicant exposure and the modulation by the gut microbiome
(2026-02-05) Lim, Joe Jongpyo; Cui, Julia Yue
The liver is an important organ for xenobiotic biotransformation and nutrient homeostasis, as well as local immunological regulation. The function of the liver is a result of unique combinations of cell types that perform specialized tasks and are further modulated by a spatial gradient that forms distinct zones, as well as external variables, such as diet. In addition, the gut microbiome, the collection of microorganisms in the gut, closely communicates with the liver through the gut-liver axis. Polychlorinated biphenyls (PCBs), which were used as industrial insulators and coolants, and polybrominated diphenyl ethers (PBDEs), which were popular flame retardants, are persistent organic pollutants (POPs) that bioaccumulate in the food chain and are readily detected in human biospecimens. Tetrabromobisphenol A (TBBPA) is globally the most widely used brominated flame retardant that replaced PBDEs. Exposure to these environmental toxicants have been closely linked to oxidative stress and inflammation, gut microbiome toxicity, and metabolic injury in the liver. PCBs, PBDEs, and TBBPA cross the placenta and are detected in breast milk, indicating that early life is a critical window for exposure to these environmental toxicants. Increasing evidence suggests that early life exposure can alter disease susceptibility or severity later in life. However, little is known regarding the cell type-specific response to early life environmental toxicant exposure and the involvement of the gut microbiome in modulating hepatic metabolic and immunological processes. Therefore, the goal of my dissertation is to strategically investigate key hepatic cell type-specific processes at both the basal level and from early life environmental toxicant exposure, as well as the contribution of the gut microbiome and diet in modulating hepatic processes. My central hypothesis is that early life environmental toxicant exposure dysregulates the metabolic and immunological landscape of the liver, further modulated by the gut microbiome and diet in vivo. I used single cell RNA sequencing (scRNA-seq) and spatial transcriptomics data of the mouse liver to systematically profile the baseline mRNA enrichment of genes that encode drug metabolizing enzymes and transporters (i.e., drug processing genes, DPGs), as well as their regulatory transcription factors in different liver cell types and zones. Furthermore, I showed that developmental PCB exposure during pregnancy and lactation resulted in cell type-specific metabolic dysregulation related to endoplasmic reticulum (ER) stress and insulin sensitivity in the livers of the offspring. From a 3 day neonatal exposure to BDE-99, a human breast milk-enriched PBDE congener, I showed that the proportion of neutrophils increased in the liver in late adulthood in mice, accompanied by a predicted increase of the macrophage inhibitory factor signaling and upregulated proinflammatory cytokine mRNA expression. Concordantly, the gut environment was altered in late adulthood from the early life BDE-99 exposure, which the changes included decreased large intestinal tight junction protein (Tjp) transcripts, altered gut microbiome, and dysregulation of inflammation-related metabolites. Microbiota transplant to germ-free (GF) mice using large intestinal content from adults neonatally exposed to BDE-99 downregulated Tjp transcripts and upregulated proinflammatory cytokines in the large intestine. I further demonstrated that the existence of a normal gut microbiome is necessary for maintaining hepatic immune tolerance. Using genetically modified mice that contain human transcripts involved in xenobiotic biotransformation and comparing various colonized microbiomes, I showed that hepatic processes are regulated by the gut microbiome, and such regulation of hepatic processes are further regulated by hepatic zones. Lastly, I showed that western high-fat diet-mediated metabolic inflammation signatures in the liver are exacerbated by developmental exposure to TBBPA, through the placenta and breast milk. Taken together, the studies in my dissertation showed that early life environmental toxicant exposure dysregulates hepatic cell type-specific responses linked to metabolic inflammation later in life, and that the gut microbiome is a modulator of metabolic and immunological properties of the liver. The studies outlined in my dissertation contribute to our understanding how early life toxicant exposures dysregulates metabolic processes in the liver and the gut environment. The mechanistic insights from the findings can further help identify novel therapeutic strategies to mitigate metabolic alterations and decrease the internal burden and effects of early life environmental toxicant exposures.
Investigating spermatogonial dynamics in vitro: Insights for reproductive and developmental toxicology
(2025-10-02) Hansen, Brad Christopher; Faustman, Elaine M; Kelly, Edward J
Neonatal development of the testis sets the stage for reproductive health throughout life. During this critical life stage, the spermatogonia migrate to the basal lamina of the tubule and establish the spermatogonial niche, the Sertoli cells proliferate and form the blood-testis-barrier to prevent autoimmune response to eventual sperm, and the adult Leydig cell lineage emerges from the mesenchyme to jumpstart testosterone biosynthesis. The balance of these acts is so important for reproductive health, though methods to study them remain limited. Classically, in vivo animal models remain the go-to model for reproductive and developmental toxicology. However, as complex cell culture methods improve and can now support dynamic systems, there are exciting opportunities to move away from in vivo models to consider mechanistic toxicology and developmental biology with complex in vitro models. The research presented in this dissertation seeks to develop and characterize novel in vitro models of the developing testis to advance the adoption of these powerful reductionist approaches in reproductive and developmental toxicology.Chapter 1 presents a state-of-the-science on the use of various in vitro models in reproductive biology, ranging from classical immortalized cell lines, to intricate three-dimensional cell printing to recreate the testis architecture. Chapter 2 describes a microculture model of the testis that dramatically reduces rodent tissue needs while retaining the necessary biological relevance and multicellular complexity. Chapter 3 details a computational assessment of bulk RNA-sequencing deconvolution techniques to characterize the cell proportions within complex in vitro models, using a neonatal testis microculture and human duodenal enteroid model as case studies. Chapter 4 focuses on the spermatogonia present within developing testis at two life stages to identify if the dynamics of differentiation and proliferation can be maintained in vitro. The research presented in this dissertation supports that in vitro are a valuable way to approach reproductive and developmental toxicology. The developmental stage of tissue, culture method, and culture supplementation are found to be critical factors when considering the phenotype and response of a model, demonstrating the necessity of benchmarking for all in vitro models. The next exciting areas are discussed, together with pilot work on human induced pluripotent stem cells models and future human tissue use in mechanistic toxicology and biology of the testis.
Sex-Specific Disruption of the Gut-Liver-Brain Axis: Developmental Programming and Behavioral Outcomes Following PCB Exposure
(2025-10-02) Suh, Youjun Park; Cui, Julia Y; Faustman, Elaine M
Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that continue to pose health risks despite being banned decades ago. Developmental exposure to PCBs has been associated with neurodevelopmental disorders that exhibit pronounced sex-specific patterns. However, previous research has focused on individual organ systems, limiting understanding of how PCBs affect integrated physiological networks during development.We investigated whether maternal PCB exposure causes sex-specific alterations across the gut-liver-brain axis using the Fox River Mixture, an environmentally relevant PCB mixture reflecting contemporary human exposure patterns. Pregnant C57BL/6J mouse dams were exposed to vehicle or PCB mixture (0.1, 1.0, or 6.0 mg/kg/day) throughout gestation and lactation, with offspring assessed at multiple developmental timepoints for behavioral, microbiome, metabolomic, and hepatic transcriptomic outcomes. Maternal PCB exposure induced dose-dependent gut microbiome disruption, enhanced hepatic xenobiotic processing, and sex-specific alterations in hepatic type 1 deiodinase (DIO1) expression. Males showed dose-dependent DIO1 upregulation while females exhibited non-monotonic responses. By PND28, distinct sex-specific patterns at the transcriptomic(?) level emerged: males exhibited extensive gut-liver molecular connectivity (>7,000 significant correlations) with enhanced hepatic detoxification responses and dose-dependent DIO1 upregulation, while females showed focused connectivity patterns in molecular networks connectivity (<3,000 correlations) with inflammatory liver activation and non-monotonic DIO1 responses. At PND35, a reversal of vulnerability was observed: males showed behavioral resilience despite continued molecular alterations, while females developed significant social memory deficits at low and medium doses with concurrent thyroid hormone suppression. Integration of microbiome, metabolomic, and transcriptomic data revealed fundamentally different network architectures between sexes. Males developed redundant, highly interconnected networks with balanced hub distribution across bacterial species, metabolites, and hepatic genes, providing system robustness. Females showed hierarchical networks dominated by specific bacterial super-hubs, creating efficiency but increased vulnerability to disruption. These architectural differences correlated with behavioral outcomes, with network topology metrics predicting functional resilience versus vulnerability. This work provides comprehensive evidence that maternal PCB exposure causes persistent, sex-specific alterations across the gut-liver-brain axis through fundamentally different biological strategies. The identification of sex-specific DIO1 regulation as a mechanism underlying differential thyroid hormone disruption, combined with distinct microbiome-metabolite-transcriptome network architectures, reveals how the same environmental exposure leads to divergent developmental outcomes. These findings emphasize the critical importance of considering sex as a biological variable in environmental health risk assessment and suggest that current regulatory frameworks based on single-sex studies may inadequately protect vulnerable populations.
Sexual Harassment Prevention in Agriculture: A Formative Evaluation of a Workplace Training Intervention
(2025-10-02) Drury, Dennise Olivia; Yost, Michael G.
Sexual harassment is an occupational hazard that endangers the health, safety, and livelihood of farmworkers. It is estimated between 50-80% of farmworker women experience workplace sexual harassment (WSH) at some point in their lives. Although numerous WSH training programs are available, limited studies have evaluated the effectiveness of these programs, especially among Spanish-speaking agricultural workers. This study evaluates the effectiveness of a tailored WSH program developed in collaboration with the agricultural community in Oregon and Washington. The evaluation study used a cross-sectional pre-post test design to assess the effectiveness of the training on agricultural workers' knowledge, attitudes, and self-efficacy in relation to WSH, reporting, and bystander intervention. The training intervention was co-designed with farmworkers in Eastern WA and was facilitated by agricultural trainers during four training sessions at the Ag Safety Days events in Washington State. Knowledge test scores for all participants significantly improved between pre and post-tests (p-value < 0.05 | 95% CI: 6.95, 2.64). Participants' test scores were not significantly different based on job, gender, or language. After the training, 14% more participants reported self-efficacy to intervene if they observed harassment. The majority of participants (n=102, 83%) reported that they perceived WSH in agriculture to be common. Only men reported they believed WSH was not common in agriculture consisting of supervisors (n=9, 5%) and workers (n=7, 6%). Findings provide evidence to suggest this training program is effective, but there is a need for additional studies to evaluate the impact of the WSH prevention programs over time.
Investigating Agricultural Exposures, Inflammation, and Child Respiratory Health in the Lower Yakima Valley of Washington
(2025-08-01) Dye, Hannah Cutler; Faustman, Elaine; Marsillach, Judit
Background: Exposure to organophosphate (OP) pesticides, a common class of insecticides used in the Lower Yakima Valley of Washington, has been linked to asthma outcomes and biomarkers in children, potentially through immunological pathways; however, mechanistic understanding of this relationship is limited. Measurement of a profile of cytokines in biological media is a powerful tool for gleaning pathophysiological insight about these respiratory responses to these agricultural exposures. Additionally, cytokines provide a perspective through which to assess temporal trends in both OP pesticide exposures and inflammatory responses, a consideration particularly important for agricultural communities with unique seasonal variability in exposure profiles. Methods: This study aims to 1) assess cytokine variability over time and across a population of children in an OP-intensive agricultural region of Washington and 2) explore relationships between low-level OP exposure and inflammatory responses related to respiratory health, notably asthma. To achieve these aims, dialkylphosphate metabolites were measured in urine and a profile of cytokines was measured in plasma throughout three agricultural seasons in 2011 for children in the University of Washington Center for Child Environmental Health Risks Research (CHC) cohort. Bayesian mixed effects models fit via Markov chain Monte Carlo Hamiltonian sampling methods were leveraged to assess seasonal and demographic variability while linear mixed effects regressions and logistic binomial regressions were used to explore relationships between OP exposure, inflammation, and asthma status. Results: Through these methods, significant seasonal variability was found for levels of IFN-? and IL-8 in child plasma for this agricultural cohort; however, no significant associations were discerned between OP exposure, inflammation, and asthma. Conclusion: This work illustrates how strategically defining systems-based cytokine profiles provides a perspective through which to gain mechanistic insight through epidemiological methods. These results highlight the importance of harnessing seasonal granularity for understanding environmental determinants of inflammation and respiratory health and that other methods of investigating these relationships may be underestimating some of the variability at play.
Understanding the Interactions Between Maternal PBDE Exposure and the Functional Gut Microbiome in Developing Mouse Offspring
(2025-08-01) Kim, Sarah; Cui, Julia
Persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs), are ubiquitously detected in the environment despite being banned from commercial and industrial use. Due to their lipophilic nature, PBDEs bioaccumulate in the human environment, including food (e.g. milk, meat, seafood), soil, and water. In humans, such exposures have been linked to inflammation and metabolic disorders. The liver is a vital organ responsible for xenobiotic metabolism and nutrient homeostasis. It functions as a central hub for digestive and systemic regulation, playing crucial roles in the metabolism of carbohydrates, amino acids, nucleotides, fatty acids, cholesterol, hormones, and especially, xenobiotics including drugs and toxicants present in our environment such as PBDEs. In close interactions with the liver, the gut microbiome can influence the host’s xenobiotic biotransformation capacity. Disruption of the microbial ecosystem–gut dysbiosis–is now recognized as a critical factor influencing disease susceptibility by modulating host metabolism, immunity, and response to environmental exposures. However, very little is known regarding how maternal exposure to PBDEs modulate the metabolic signatures involved in obesity/diabetes and inflammation later in life, and how microbial metabolites, such as indole-3-propionic acid (IPA) could modify the effect of PBDEs during the interplay between endogenous versus toxicological pregnane X receptor (PXR) activation, an important nuclear receptor for xenobiotic biotransformation. Therefore the goal of my dissertation is to investigate how developmental PBDE exposure disrupts the gut microbiome and microbial metabolism of tryptophan (Aim 1), as well as to investigate whether microbial indole metabolites and indole derivatives reduce inflammation and improve diabetic- or inflammation-related phenotype following developmental PBDE exposure (Aim 2), and lastly to determine whether targeting gut microbiome mechanistically contributes to developmental PBDE exposure-mediated disruption of PXR signaling and delayed onset of obesity and inflammation (Aim 3). I hypothesized that maternal PBDE exposure induces acute and persistent gut dysbiosis, disrupting the interplay between endogenous PXR activation (by indoles) and xenobiotic PXR activation (by PBDEs), ultimately contributing to the delayed onset of obesity and inflammation. To achieve Aim 1, breeders of conventional (CV) humanized PXR-transgenic (hPXR-TG) mice were exposed to vehicle, 0.1 mg/kg/day DE-71 via diet, DE-71+IPA (20 mg/kg/day via drinking water), or IPA from 4 weeks preconception until end of lactation, whereas weaned pups were fed standard chow with no DE-71 with or without IPA supplementation via drinking water. Organs were collected at postnatal day (PND) 21, 3 months, and 6 months of age. Targeted and untargeted metabolomic responses were analyzed with metagenomic shotgun sequencing to identify differentially abundant bacterial taxa and predict microbial functional changes associated with PBDE exposure. For Aim 2, serum immunoassays, cytokine and chemokine levels in the intestine and liver, and liver histopathological analysis were assessed in PND21, 3 months, and 6 months of age. Overall, the maternal DE-71 exposure on the gut microbiome of pups were amplified over time. The regulation of hepatic cytokines and prototypical xenobiotic-sensing transcription factor target genes by DE-71 and IPA was age- and sex-dependent, where DE-71-induced mRNA increased selected cytokines (Il10, Il12p40, Il1β [both sexes]). The hepatic mRNA of the aryl hydrocarbon receptor (AhR) target gene Cyp1a2 was increased by maternal DE-71 and DE-71+IPA exposure at PND 21 but intestinal Cyp1a1 was not altered by any of the exposures and ages. In addition, maternal DE-71 exposure increased serum indole, a known AhR ligand, in age- and sex-dependent manner. To achieve Aim 3, 3 months- and 6 months-old germ-free (GF) hPXR-TG mice were used for fecal microbiota transplantation (FMT) using fecal donors from CV control and DE-71-exposed mice were utilized. To investigate whether gut microbiome perturbations contribute to PBDE-mediated disruption of PXR signaling and delayed-onset inflammation, analysis of inflammatory signaling in metabolic organs, xenobiotic-sensing transcription factor-target gene expression, RNA sequencing, metagenomic shotgun sequencing, and targeted and untargeted metabolomics were assessed across multiple tissues. Overall, the microbiome from DE-71 exposed donors produced more pronounced changes in the hepatic transcriptomes of the female recipients than males, with enriched pathways linked to sterol and cholesterol metabolism and stress-activated protein kinase signaling cascades. Interestingly, exposed GF male recipients exhibited enrichment of pathways related to xenobiotic metabolism and fatty acid metabolic processes. In the large intestinal tissues, transcripts of tight junction genes Tjp1 and Tjp2 were consistently downregulated, indicative of compromised intestinal barrier integrity, or “leaky gut,” likely driven by DE-71-induced gut microbiome dysbiosis. Furthermore, hepatic inflammatory markers were more pronounced in female recipients compared to males, suggesting sex-specific susceptibility to inflammation following microbial transfer. In conclusion, my findings demonstrate that maternal PBDE exposure induces a proinflammatory signature along the gut-liver axis, characterized by gut dysbiosis, disrupted tryptophan metabolism, and attenuated PXR signaling in postweaned hPXR-TG offspring over time. Notably, these effects were partially mitigated by IPA supplementation, highlighting the potential of microbiome-derived metabolites in counteracting environmentally-induced metabolic dysfunction.
Nonprofit Hospitals and Climate-Sensitive Hazards: A Content Analysis of Community Health Needs Assessments in High-Risk United States Counties
(2025-08-01) Carter, Rachael; Hess, Jeremy J
Aim: This study aims to examine the extent to which nonprofit hospitals describe climate-sensitive hazards in their community health needs assessments (CHNAs).Background: Climate change is a pressing public health problem that calls for supportive programming tailored to communities. Nonprofit hospitals are uniquely positioned as medical anchor institutions to support their communities as climate-sensitive hazard risk increases through federally mandated CHNAs and community benefit investments. Design: We performed a content analysis of nonprofit hospital CHNAs in United States counties determined to have Very High Risk of natural hazard impacts, as determined by the National Risk Index (NRI). We assessed what climate-sensitive hazards are included in CHNAs and how they are described, including whether they are identified as a priority health need, which has been shown to indicate greater hospital investment in implementations to address the health need. Following content analysis, hospital and community characteristics were compared to assess for differences between hospitals that did and did not include climate-sensitive hazards as a priority health need. Results: In a sample of 168 hospitals, the majority (85.1%) describe at least one climate-sensitive hazard in their CHNA. However, few (11.9%) consider these climate-sensitive hazards a priority health need of their community. Air pollution is the most commonly described climate-sensitive hazard (61.3%). Hospital and community characteristics did not differ between hospitals that did and did not indicate climate-sensitive hazards as a priority health need, with one exception: hospitals that included climate-sensitive hazards as a priority health need were located in counties with lower poverty rates. Conclusion: In conclusion, our study suggests that while most hospitals in counties with Very High Risk of natural hazards mention at least one climate-sensitive hazard in their CHNAs, few consider them a priority health need of their community. Further research is needed to examine the national distribution of nonprofit hospitals' inclusion of climate-sensitive hazards in CHNAs and implementation strategies, as well as to understand the barriers and facilitators for hospital leadership in describing climate-sensitive hazards as priority health needs in their communities.
Sexually Transmitted Infection Wastewater-Based Surveillance in Rural and Urban Washington State
(2025-08-01) Koger, Briahna Lynne; Fuhrmeister, Erica R.
Much like the microbes in our guts, sexually transmitted infections (STIs) have been with humans for as long as we can remember, and impact millions of people each year around the globe – as they have for millennium. In Washington State, cases of Neisseria gonorrhoeae (gonorrhea), Chlamydia trachomatis (chlamydia), and Treponema pallidum (syphilis) are on the rise and impacting the health of communities. Stigma and asymptomatic infections make it difficult to have representative case data of STIs due to underreporting at the clinical level. In this study, we surveilled N. gonorrhoeae, C. trachomatis, and T. pallidum in wastewater influent in Washington state. We collected twice weekly samples from five different wastewater treatment plants across Washington state, representing urban and rural communities, between November 2024-February 2025. Solids were separated from wastewater using centrifugation and DNA was extracted using a modified AllPrep Powerviral DNA/RNA (Qiagen) protocol. To quantify our three targets, we developed a triplex digital PCR (dPCR) assay for all three STI targets. We identified C. trachomatis at all five locations and in 65% (86/132) of total samples. Of the five surveyed systems, one location (WWTP WA5) is an adequate candidate for continuing wastewater-based epidemiology for C. trachomatis, with 87.5% (21/24) samples positive for C. trachomatis compared to 41.7-70.8% positive in other locations. Wastewater surveillance data on N. gonorrhoeae, C. trachomatis, and T. pallidum can inform interventions and actions by local health jurisdictions as well as college campuses. Potential responses include targeted campaigns to encourage STI testing and treatment. Additionally, wastewater surveillance can benefit rural communities in WA where STI stigma and barriers to healthcare are more common.
Characterizing drug use incidents on transit vehicles and its impact on transit operators
(2025-08-01) Srikanth, Pranav; Baker, Marissa G.
Drug misuse, specifically of synthetic opioids and methamphetamines, has increased in the United States, often occurring on public transit, creating potential for secondhand exposure for transit operators. These exposures could result in physical or mental health impacts. Here, we characterize drug use incidents on transit vehicles and its impacts on transit operators. Using a quantitative survey of transit operators in the Pacific Northwest, we fit ordinal logistic regression models to investigate transit operators’ perceived risk of workplace exposure to drug use incidents, occupational stress, and job satisfaction, and their association with intent to leave their job. We found that higher perceived risk scores were significantly positively associated with greater intent to leave (OR: 1.08; 95% CI: 1.02, 1.14), but occupational stress and job satisfaction, which were significantly associated with greater intent to leave, attenuated this relationship.We subsequently conducted qualitative interviews of transit operators to explore their experiences with passenger drug use, risk perceptions, impacts, availability and effectiveness of existing supports and guidance pertaining to passenger drug use, and whether there are unfulfilled needs in these supports. Interviewees reported physical health effects, mental health outcomes, and emotional impacts. Risk perceptions of passenger drug use were prevalent and may be exacerbated by outrage factors. Operators reported a lack of support from their agencies, and highlighted engineering controls as an effective intervention that is currently unfulfilled. We then examined temporal and weather-related trends in drug use on transit, based on previous transit operator concerns that people who use drugs (PWUD) seek transit vehicles as shelter to escape from inclement weather. Using a dataset of drug use incidents reported by transit operators in King County, Washington, in 2022, we fit a Poisson regression model to understand the association between daily incident count and daily weather patterns. Reported drug use incidents showed clear temporal trends, with a higher frequency of incidents in winter and spring than in summer; April had the highest mean daily incident count of 7.3 incidents/day. Higher temperature was significantly associated with lower incident count (IRR: 0.96; 95% CI: 0.95, 0.97). The work presented here highlights the impacts of drug use incidents on transit operators, and can help guide the development and timely deployment of interventions that can improve the work experiences of transit operators.
Developing and Validating a Framework for Estimating Pesticide Use in Washington State
(2025-08-01) Jennifer, Catherine; Kasner, Edward
Understanding spatial patterns of pesticide use is critical for environmental monitoring, public health protection, and informed policymaking, particularly in agriculturally intensive regions such as Fresno County, California, and Yakima County, Washington. This study compared two major pesticide data sources—the California Pesticide Information Portal (CalPIP) and the United States Geological Survey (USGS) pesticide use estimates—to assess their agreement and accuracy at the Township Range Section (TRS) scale, which is part of the Public Land Survey System (PLSS) and was created by the United States government in the early 1800s to divide land into rectangular parcels. Focusing on orchard, vineyard, and nut crops, we evaluated pesticide application trends across three key time points (2000, 2010, and 2019/2020) and mapped the distribution of the most commonly used active ingredients, including sulfur, glyphosate, petroleum oil, kaolin, and chlorpyrifos. Our analysis revealed notable differences between the two data sources. CalPIP provided high-resolution, crop-specific pesticide application data, enabling detailed spatial visualizations at a fine resolution. In contrast, USGS data, which was modeled from county-level crop acreage and average application rates, lacked crop specificity and resulted in more generalized spatial patterns. Despite these differences, both sources highlighted similar high-use regions, indicating that USGS data, although limited, can be used with caution for a more generalized geographic analysis of pesticide use across 49 states outside of California. Validation analysis between USGS and CalPIP grid estimates revealed weak positive correlations, revealing methodological inconsistencies between the two sources, including data suppression, reporting gaps, and the generalized non-specific nature of USGS estimates. These findings highlight the need for improved pesticide use estimation methodologies that can be ground-truthed with satellite imagery and local surveys to improve the accuracy and applicability of pesticide exposure assessments.
Enhancing Resilience to Wildfire Smoke in Alaska: Evaluating and Communicating the Use of Air Quality Data for Health Protection
(2025-08-01) Cortes Espinosa, Mariana; Busch Isaksen, Tania
In recent decades, Alaska has experienced unprecedented wildfire seasons, increasing the public’s exposure to harmful particulate matter from wildfire smoke. To track this air pollution for the entire state, there are only six federal regulatory air monitoring stations that continuously monitor fine particulate matter (PM2.5). Moreover, these monitoring sites are all located within the population centers of Anchorage, Fairbanks, and Juneau. This leaves significant gaps in real-time exposure assessment and trend tracking of wildfire smoke for rural and Alaska Native communities far from air monitoring sites, limiting their ability to make informed exposure-reduction decisions in a timely manner. As a result, strategies such as the use of low-cost air quality sensor networks and web-based tools that share air quality data from multiple sources, are needed to supply air quality information to rural communities. Low-cost air quality sensor networks have been used to provide individuals with real-time, personalized exposure data for air pollution, that help inform exposure assessment efforts. While there is some understanding of benefits and challenges involved with using low-cost sensor networks for air pollution planning and response efforts, most studies have examined networks located in urban areas, and few have examined them in the context of wildfire smoke. Further, limited evaluations have been conducted on the usability of low-cost sensors and how it influences their effectiveness as an intervention for wildfire smoke resilience. Additionally, a new state-wide tool–the Alaska Wildfire Explorer–was recently developed by researchers at the University of Alaska Fairbanks to provide geographically-relevant fire and air quality information in an accessible web-based format that incorporates data from low-cost sensors. Still, there is a need for tailored guidance on interpreting and applying data from this tool to inform exposure-reduction strategies during wildfire smoke events at both the community and individual levels. This study aims to (1) describe the barriers and facilitators to the implementation and use of low-cost air quality sensors in Alaska and to (2) co-create story-based user guides that communicate the utility and functionality of the Alaska Wildfire Explorer tool. For aim 1, we applied the Consolidated Framework for Implementation Research (CFIR) and Proctor et al.'s Implementation Outcomes as a conceptual framework to identify key factors that influenced implementation processes and innovation outcomes. We employed semi-structured interviews and a survey tool to investigate perspectives of implementation leads, innovation deliverers, and innovation recipients of low-cost sensor networks in Alaska. We found that although low-cost air quality sensors are not perceived as challenging to install and maintain, Alaska’s extreme winter weather, variable internet infrastructure, and limited resources within the work infrastructure allocated to low-cost monitoring posed barriers to the sustainability of this innovation. This evaluation also revealed that although some surveyed communities use air quality data to inform risk communication messages and local initiatives to reduce exposure to air pollution, the vast majority would like to. Additionally, most sensor hosts are not currently using data from their sensors to make wildfire smoke-related evacuation decisions. These findings indicate that investments in community infrastructure to support sensor durability and Wi-Fi connectivity, as well as providing additional training for sensor hosts on accessing and interpreting air quality data, can help improve the sustainability of low-cost air quality sensor networks in Alaska for access to real-time air quality data. For aim 2, we used a co-production process and a storytelling approach rooted in scientific and environmental communications to create five story-based user guides communicating the utility of the Alaska Wildfire Explorer tool to help promote personal and community health resilience during wildfire smoke events. Reflections on co-creation aspects that influenced the final public health communication products and recommendations for future co-production efforts are described.
Occupational Health in U.S. Transit Agencies: Trends in OSHA-Reportable Illnesses and Injuries (2016–2023)
(2025-08-01) Solaro, Hunter David; Baker, Marissa
Introduction: Transit workers in the United States face a host of occupational health hazards including chronic exposure to physical, chemical, and psychosocial agents. A systematic review of 187 studies identified that all workers suffering hazardous occupational noise exposure can cause permanent auditory threshold shifts, though the evidence for elevated risk among railway workers is mixed, with some studies showing minimal or no increased loss relative to reference populations. Respiratory illness is a recognized occupational concern for transit workers, driven in part by elevated exposures to airborne pollutants in enclosed and high-density transit environments. Measured concentrations of fine particulate matter (PM₂.₅) inside buses and subways, coupled with inadequate ventilation or filtration, contribute to inflammation and increased risk of chronic respiratory conditions, and musculoskeletal disorders driven by static postures and vibration.1,2,3,4,5 These exposures may contribute to a higher prevalence of hypertension, diabetes, and mental health conditions among transit employees compared to the general workforce.6 Despite the severity and persistence of these conditions, occupational health surveillance and regulatory prioritization in the transit sector remain fragmented and underdeveloped.6,7,8 Efforts to quantify these burdens are further complicated by systemic underreporting, definitional inconsistencies, and jurisdictional barriers to case recognition.8,9,10 This thesis explores these gaps by examining national Occupational Safety and Health Administration’s (OSHA’s) Injury Tracking Application (ITA) data from 2016–202311, with analyses by agency size, North American Industry Classification System (NAICS) classification12, and geographic context. The ITA dataset offers establishment-level detail enabling trend analysis by agency characteristics. The findings aim to inform targeted policy responses and advance data-driven protections for transit workers across the country.Our hypothesis is that OSHA-reportable rates of hearing loss, poisonings, respiratory disorders, skin disorders, days away from work, other illnesses, deaths, and total illness, differ significantly over time and by agency subgroup, particularly size and geographic classification. This will be evaluated through: Aim 1: Assess temporal trends in illness rates across the study period (2016–2023). Aim 1A: Identify statistically significant differences between individual years. Aim 1B: Examine whether respiratory illness rates increased during the COVID-19 pandemic (2020–2021). Aim 2: Compare illness rates across transit agency subgroups. Aim 2A: Assess statistically significant differences in illness rates by establishment (agency) size classification. Methods: A retrospective descriptive study design was applied using OSHA’s ITA data by NAICS codes 4851 for urban transit systems and 4852 for interurban and rural bus transportation and establishment level information such as, total hours worked at the agency in the previous year, agency size, and geographic location. The ITA is composed of OSHA-reportable cases, which include any work-related fatality, loss of consciousness, days away from work, restricted duty, job transfer, or injuries and illnesses requiring medical treatment beyond first aid. Also included are diagnosed cases of cancer, chronic irreversible diseases, fractured bones or teeth, punctured eardrums, and cases meeting specific recording criteria such as needlestick injuries, medical removal, hearing loss, tuberculosis, and work-related Covid-19 reported as respiratory conditions.13 Rates were calculated per full-time equivalent (FTE) employees to normalize across agency size based on hours worked. Variables such as geographic region, agency size, and transit classification based on NAICS codes for urban transit vs. interurban and rural bus transportation, were incorporated into the analysis. Analytical methods included Mann-Kendall trend tests to assess changes in illness and injury rates from 2016 to 2023. Year-to-year differences were evaluated using Kruskal-Wallis tests, and one-way ANOVA was used to compare rates across pandemic periods. Linear regression models were applied to examine associations between illness rates and agency-level characteristics such as size, region, and NAICS classification. A hierarchical clustering method was used to normalize and merge establishment records across years by grouping similar company names and addresses, improving consistency in longitudinal analysis. Results: OSHA-reportable illness and injury rates in U.S. transit agencies remained largely stable between 2016 and 2023, with no apparent trends observed. While respiratory conditions and poisonings showed increases in 2021 and 2022 respectively, these increases were not statistically significance. Only injury rates varied significantly by year, spiking in 2021, though these were not statistically significant after adjustment. Linear regression models, excluding state-level predictors, identified agency size was a modest but statistically significant predictor of hearing loss (β = 0.0925, 95% CI [0.0667, 0.1183]), though the overall model fit was poor (adjusted RÂ² = 0.026). Conclusion: This thesis presents a national, retrospective multi-year assessment of OSHA-reportable illness and injury trends among reporting U.S. transit employers from 2016 to 2023. While rates remained generally stable over the study period, the ability to predict illness and injury patterns based on agency-level characteristics captured in ITA data was limited. This limitation likely reflects the narrow scope of available variables, which exclude key factors such as worker demographics, job classifications, and exposure conditions. These limitations emphasize the need for improved occupational health surveillance in both urban and rural transit sectors. A more robust and integrated surveillance system would better equip health and safety practitioners to identify patterns early and implement preventive strategies. Future research should incorporate workers’ compensation records, Federal Transit Administration (FTA) datasets, and proactive hazard monitoring, with a focus on high-risk roles and standardized reporting practices.
Health Impacts of Acute Wildfire Smoke Exposure on the Active-Duty Military Population at Joint Base Lewis-McChord, Washington, USA
(2025-08-01) Robinson, Mark S.; Mease, Luke E
Wildfire smoke is an increasingly recognized health risk worldwide. This study investigates the short-term health impacts of acute wildfire smoke exposure among active-duty military personnel stationed at Joint Base Lewis-McChord (JBLM), Washington, USA, from 2018 to 2024. Using two PM₂.₅ thresholds (≥35.4 Âµg/mÂ³, corresponding to the EPA’s “Unhealthy for Sensitive Groups,” and ≥20.4 Âµg/mÂ³, based on previous studies), we assessed emergency department (ED) visits for respiratory, cardiovascular, and behavioral health outcomes. We employed conditional logistic regression models adjusting for daily average temperature and examined lag effects from 0 to 7 days prior to ED visits.Our findings reveal that even moderate PM₂.₅ levels were associated with increased odds of respiratory and behavioral health ED visits. For respiratory visits adverse effects emerged after a lag period (e.g., lag 4). Behavioral health outcomes including anxiety, mood disorders, and depression, were significantly elevated several days post-exposure. This outcome underscores the potential mental health burden of wildfire smoke. While asthma and angina visits showed no consistent patterns, these analyses were limited by smaller sample sizes. The results highlight the vulnerability of even a relatively healthy military population to wildfire smoke, with implications for broader public health. Future research should examine the role of preexisting conditions, additional pollutants, and exposures at other military installations. Mitigation strategies, such as an “air category” system, may help safeguard both military readiness and civilian well-being in an era of increasing wildfire frequency and intensity.
MASTER OF SCIENCE
(2025-08-01) Magnus, Timothy Obadiah; Hovis, Emily EH; Meschke, Scott SM
Abstract The use of antibiotics in dairy farming plays a crucial role in maintaining animal health and productivity. However, growing concerns over antimicrobial resistance (AMR) have driven regulatory reforms and shifts in on‑farm antibiotic management in recent years. This study assessed current antibiotic usage patterns, animal health management practices, and antimicrobial stewardship among Washington State dairy farms. A structured questionnaire was emailed to 190 licensed dairy farms in Washington State (WSDA list), with reminder calls to boost participation. 24 farms (12.6%) responded, representing herd sizes from fewer than 25 animals to more than 1,000. Data were analyzed in R using descriptive statistics to quantify practices and Chi‑square tests to explore associations between producer roles and antibiotic awareness. Therapeutic use of cephalosporins (e.g., ceftiofur) and penicillins dominates, with non‑therapeutic applications (medicated milk replacers, feed top‑dressing) now nearly eliminated. Routine health checks (88 %), glove use (75 %), and handwashing (67 %) are widespread. One‑third of farms employ daily cleaning, grooming, and footbaths; 25 % test colostrum immunoglobulins (up from 8 % in 2003). Although 86 % screen new purchases for diseases (BVD, Johne’s, etc.), only 29 % quarantine arrivals for the recommended 14–28 days. On AMR Awareness, fifty‑eight percent report high knowledge of antibiotic resistance and 62.5 % correctly define it (vs. < 40 % in 2005). Seventy‑five percent see resistant infections as a herd threat; 59 % recognize human‑health impacts. Yet 29 % fear higher mortality without prophylactic antibiotics. Forty‑five percent rely on internet resources; 33 % attend extension meetings; others use journals or newsletters, indicating a hybrid digital/traditional outreach landscape. The findings of this study underscore a notable evolution in antibiotic management and preventive health strategies among dairy farms in Washington State. The adoption of targeted therapeutic antibiotic use—especially cephalosporins and penicillins for conditions like mastitis and respiratory disease—signals a clear departure from non-therapeutic applications such as medicated milk replacers and feed top-dressing. These results support a theoretical framework in which informed attitudes, producer roles, and farm resources collectively shape antibiotic stewardship behavior. Notably, producers demonstrating higher awareness of antimicrobial resistance (AMR) also exhibited more rigorous hygiene practices and narrower antibiotic use, reinforcing behavior-change models that link knowledge acquisition with practical decision-making. In conclusion, Washington State dairy farms have made notable progress toward responsible antibiotic stewardship embracing precision therapy, strengthening hygiene, and increasing AMR awareness. Remaining gaps in quarantine practices and persistent reliance on prophylactic antibiotics highlight areas for targeted extension and research. A blended outreach model, combining digital and in‑person methods, alongside practical tools (e.g. quarantine guidelines, colostrum‑testing protocols), will be key to sustaining improvements in animal health, farm productivity, and public health protection.
Associations Between Long-Term Ambient Air Pollution, Neighborhood Physical Disinvestment, and Incident Diabetes in the Hispanic Community Health Study/Study of Latinos
(2025-08-01) Smith, Cara; Kaufman, Joel
Risk factors for type 2 diabetes (T2D) include genetics, age, adiposity, diet, physical activity (PA) levels and environmental conditions.1–3 Putative environmental risk factors include exposure to air pollution-- specifically traffic-related air pollutants--and neighborhood conditions.4–7 A meta-analysis by Yang et al.5 of 11 studies reported an association between fine particulate matter (PM2.5) and incident T2D (HR= 1.10, 95% CI: 1.04-1.17 per 10 μg/m3 increment). Studies on NO2 have been limited and associations more mixed for incident T2D.5 There have previously been a limited number of studies on neighborhood environment, specifically neighborhood physical disinvestment (formerly referred to as disorder), and T2D. Disinvestment in the built environment is a result of systemic social and economic processes that deprive areas of resources needed to maintain and develop physical environments. Disinvestment is reflected in visual indicators of deterioration and neglect, and is a concern for health as areas of high disinvestment may reduce resident’s ability and willingness to engage in PA.8 Increasing neighborhood disorder has also been found to interact with genetic risk of T2D, as those with higher polygenic score for T2D (a summary of genome-wide genetic risk) living in neighborhoods of higher levels of disorder had a greater risk of T2D.9 Data on air pollution, neighborhood environment, and T2D risk is limited and even more so in Hispanic/Latino populations and subgroups at high risk of diabetes. This dissertation addresses those data gaps in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a longitudinal community-based cohort study of 16,415 self-identified Hispanic/Latinos recruited between 2008 and 2011 from the Bronx, Chicago, Miami, and San Diego. Yearly follow-up calls were conducted and a second visit occurred between 2014-2017. Laboratory analysis from both exams includes fasting plasma glucose (FPG) and Glycosylated hemoglobin (HbA1c). Diabetes was defined in two way: the primary definition for diabetes required a FPG ≥126 mg/dL; HbA1c level ≥6.5%; post-OGTT glucose ≥ 200 mg/dL; and/or self-reported use of antihyperglycemic drugs,10 and the secondary definition included all those who fit the primary definition of T2D and additionally includes those who self-reported diabetes or high sugar in their blood. Additionally, different progression of diabetes were investigated and pre-diabetes was defined as having a FPG ≥100 mg/dL and <126 mg/dL; and HbA1c level ≥5.7% and <6.5%.10 The different progression of diabetes were: 1) progression from pre-diabetes to diabetes, where the sample only included those with pre-diabetes at baseline, 2) Progression of those free of diabetes and pre-diabetes to diabetes and 3) progression of those free of diabetes and pre-diabetes at baseline to pre-diabetes at visit 2. The first aim of this dissertation focuses on estimating long-term exposure to ambient PM2.5 and NO2 in HCHS/SOL cohort members and the association of these pollutants with incident diabetes, and if these associations are modified by physical activity levels and/or adiposity. A spatiotemporal model was used to estimate air pollution exposure at residential addresses. Individual survey-weighted Poisson regression models were used to assess the association between each air pollutant’s average concentration over the follow-up period and incident diabetes at visit 2. Of the 8248 participants free of diabetes (primary definition) at visit 1, there were 950 incident diabetes cases at visit 2 with an age-centered adjusted incidence rate of 16.3 per 1000 person-years. For the secondary diabetes definition, 8129 participants were free of diabetes at visit 1 and there were 1354 incident cases by visit 2 with an age-centered adjusted incidence rate of 24.5 per 1000 person-years. When utilizing the primary definition of diabetes, a 2.48 μg/m3 increase in PM2.5 was associated with a 27% increased risk of incident diabetes when adjusting for age and sex (IRR = 1.27, 95% CI: 1.09 – 1.49). An 8.69 ppb increase in NO2 was associated with a 22% increased risk of incident diabetes when adjusting for age and sex (IRR = 1.22, 95% CI: 1.08 – 1.37). Associations with both PM2.5 and NO2 were attenuated and no longer statistically significant when adjusting for years living in the US, income, educational attainment, family history of diabetes, neighborhood SES, waist circumference, and study center/ethnic heritage. There was no evidence of effect modification by physical activity or waist circumference. When adjusting for our main set of covariates at each study center, higher exposure to PM2.5 and NO2 were only associated with increased risk of incident diabetes at the Bronx study center. Future studies should continue to investigate the association between PM2.5 and NO2 and incident diabetes in a less spatially clustered cohort with a longer follow-up period. Future studies should also continue to investigate the potential modifying effects of physical activity and adiposity. The second aim of this dissertation focused on generating neighborhood disinvestment scores for each participants’ residential address in the HCHS/SOL and investigated the association between baseline neighborhood disinvestment and incident diabetes at visit 2. A virtual street audit of Google Street View Imagery was conducted and an item response theory model was fit to indicators (litter, graffiti, under-maintained buildings, bars on windows, and abandoned buildings) to form a scale measuring a latent level of disinvestment. Ordinary kriging was used to estimate levels for each residential address within the HCHS/SOL census tracts via spatial interpolation. Covariate-adjusted and survey-weighted Poisson regression models were used to investigate the association between neighborhood disinvestment and incident diabetes at visit 2 among 9120 participants free of diabetes at visit 1. A sensitivity analysis among those who did not move during the follow-up period was conducted as well. A one-standard deviation increase in neighborhood disinvestment score was associated with a 13% (95% CI: 1%-23%) lower risk of incident diabetes when adjusting for age, sex, education, income, study center/heritage, years in the US, family history, and a neighborhood socioeconomic index. Our sensitivity analysis yielded qualitatively similar results with lower precision. Overall, our analysis does not support the hypothesis that neighborhood physical disinvestment is associated with incident type 2 diabetes in this Hispanic/Latino population. Future studies should continue to evaluate the role of food environment, greenspace, and physical activity when considering neighborhood scale infrastructure impacts on diabetes risk.
Beyond Expectations: Characterizing and Expanding the Roles of Community Health Workers in Environmental Health and the Built Environment
(2025-08-01) Lim, Pamela; Austin, Elena; Berney, Rachel
Community health workers (CHWs) enhance the fields of public health and medicine. They are known to improve trust and connection between institutions and communities that experience barriers to care. Meanwhile, most public institutions struggle to sufficiently reach all the communities they seek to support. This research investigates how community health workers contribute to their current projects and considers if and how the community health worker model can be applied to non-medical settings or fields other than medicine and public health. This research was completed in collaboration with Public Health – Seattle & King County’s Community Health Worker Asthma Program (CHW Asthma Program) and the Airport, Air Quality, and Asthma Research Study (AAA Study), a research project under the University of Washington’s Department of Environmental and Occupational Health Sciences. It investigated the roles of community health workers in the CHW Asthma Program and the AAA Study, where they are mediators, educators, and advocates of their clients. This research evaluated the AAA Study Protocol and suggests that community health workers strengthened the AAA Study by enhancing participants’ engagement and satisfaction and by providing insights as to how participants would interact with study materials. This research also conducted the CHW Roles Study, a qualitative analysis of the experiences of community health workers. It found that they are skilled professionals who make personal connections with their clients based on respect and autonomy. This analysis found that CHWs support clients with many resources and topics, including non-medical care, if they have access to training and resources. Additionally, CHWs can be better supported in their work with more stable funding, training and education, and access to mental health care. This research supports the importance of community health workers in public health and research. It also suggests that expanding the role of CHWs beyond these fields can help other institutions engage more meaningfully with their residents and constituents. Hiring community health workers or other liaisons can increase community engagement and public participation, improve trust, and support a shift toward more collaborative decision-making between institutions and the communities they seek to support.
Heatwaves and Herbicides: Exploring the Relationship Between Temperature and Glyphosate Exposure
(2025-08-01) Martindale, Cecilia; Sheppard, Lianne
Among the implications of climate change, higher temperatures may increase exposure to and absorption of hydrophilic substances like glyphosate, a widely used herbicide in the U.S. and worldwide. This study aims to explore spatial co-exposures of heat and glyphosate across the United States using descriptive and interactive mapping, characterization of wet bulb globe temperatures in the United States, and with nationally representative data from NHANES. This innovative research contributes to a deeper understanding of the complex interplay between warming ambient temperatures and environmental health hazards, emphasizing the necessity of addressing these interconnected challenges in the context of a warming climate.

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