Long-Term Impact of Childhood Adversity on the Gut Microbiome of Nursing Students.

Adverse childhood experiences (ACEs) encompass negative, stressful, and potentially traumatic events during childhood, impacting physical and mental health outcomes in adulthood. Limited studies suggest ACEs can have short-term effects on children's gut microbiomes and adult cognitive performance under stress. Nevertheless, the long-term effects of ACEs experienced during adulthood remain unexplored. Thus, this study aimed to assess the long-term effects of ACEs on the gut microbiota of adult nursing students. We employed a multidimensional approach, combining 16S rRNA sequencing, bioinformatics tools, and machine learning to predict functional capabilities. High-ACE individuals had an increased abundance of Butyricimonas spp. and Prevotella spp. and decreased levels of Clostridiales, and Lachnospira spp. Prevotella abundance correlated negatively with L-glutamate and L-glutamine biosynthesis, potentially impacting intestinal tissue integrity. While nursing students with high ACE reported increased depression, evidence for a direct gut microbiota-depression relationship was inconclusive. High-ACE individuals also experienced a higher prevalence of diarrhea. These findings highlight the long-lasting impact of ACEs on the gut microbiota and its functions in adulthood, particularly among nursing students. Further research is warranted to develop targeted interventions and strategies for healthcare professionals, optimizing overall health outcomes.

Implications of disparities in social and built environment antecedents to adult nature engagement.

Antecedent factors which influence adult engagement with nature are underexplored given the human health benefits strongly associated with nature exposure. Formative pathways and impediments to nature contact merit understanding as they may contribute to later-life health disparities. We probed experiential pathways and attitudes toward nature engagement among adults purposefully sampled across U.S. regions, age, race/ethnicity, and urbanicity through semi-structured focus group discussions. The research aims were to explore entryways and barriers to experiencing nature and learn how natured and built environments compete in influencing human-nature relationships. Sessions were recorded, transcribed, and analyzed following Braun and Clarke's phases of thematic analysis. Qualitative content analysis of discussions identified three principal themes: 1) formative influences promoting adult nature engagement (i.e., persons/organizations and places of origin), 2) detractors from nature engagement (i.e., perceptual, material, and physical barriers), and 3) role of current setting (i.e., natural and built environments) shaping nature-seeking relationships. We found experiential factors that included early life exposures outdoors, personal mentorship, and organizational affiliation to be highly influential in socializing individuals to nature and in soldering attachment to nature which manifests into adulthood. In contrast, changing demographics and childhood, inequity, social dynamics, metropolitan growth, urban renewal explained alienation from nature. These findings emphasize the importance of efforts to expand opportunities for nature contact, especially for youth living in economically challenged urban areas, which go beyond increasing greenspace to encompass mentoring partnerships for gaining skills and comfort outdoors and redesign of safe natured spaces within cities for hands-on learning and discovery.

Influence of living in the same home on biomonitored levels of consumer product chemicals.

BACKGROUND: Individuals living in the same home may share exposures from direct contact with sources or indirectly through contamination of the home environment. OBJECTIVE: We investigated the influence of sharing a home on urine levels of ten phenolic chemicals present in some consumer products. METHODS: We used data from Silent Spring Institute's Detox Me Action Kit (DMAK), a crowdsourced biomonitoring program in the US. Of the 726 DMAK participants, 185 lived in the same home with one or more other DMAK participants (n = 137 pairs, up to six participants in a home). The concentration distributions included values below the detection limit so we used statistical methods that account for left-censored data, including non-parametric correlation estimation and hierarchical Bayesian regression models. RESULTS: Concentrations were significantly positively correlated between pair-members sharing a home for nine of the ten chemicals. Concentrations of 2,5-dichlorophenol were the most strongly correlated between pair-members (tau = 0.46), followed by benzophenone-3 (tau = 0.31) and bisphenol A (tau = 0.21). The relative contribution of personal product use reported product use of other household members (up to 5 others), and the residual contribution from a shared household, including exposures not asked about, varied by chemical. Paraben concentrations were largely influenced by personal behaviors whereas dichlorophenol and bisphenol concentrations were largely influenced by shared home exposures not related to reported behaviors. SIGNIFICANCE: Measuring the influence of personal and household practices on biomonitoring exposures helps pinpoint major sources of exposure and highlights chemical-specific intervention strategies to reduce them.

Indoor humidity levels and associations with reported symptoms in office buildings.

Moderate indoor relative humidity (RH) levels (i.e., 40%-60%) may minimize transmission and viability of some viruses, maximize human immune function, and minimize health risks from mold, yet uncertainties exist about typical RH levels in offices globally and about the potential independent impacts of RH levels on workers' health. To examine this, we leveraged one year of indoor RH measurements (which study participants could view in real time) in 43 office buildings in China, India, Mexico, Thailand, the United Kingdom, and the United States, and corresponding self-report symptom data from 227 office workers in a subset of 32 buildings. In the buildings in this study, 42% of measurements during 9:00 - 17:00 on weekdays were less than 40% RH and 7% exceeded 60% RH. Indoor RH levels tended to be lower in less tropical regions, in winter months, when outdoor RH or temperature was low, and late in the workday. Furthermore, we also found statistically significant evidence that higher indoor RH levels across the range of 14%-70% RH were associated with lower odds of reporting dryness or irritation of the throat and skin among females and unusual fatigue among males in models adjusted for indoor temperature, country, and day of year.

Responding to Natural and Industrial Disasters: Partnerships and Lessons Learned.

OBJECTIVES: The aim of this study was to provide insights learned from disaster research response (DR2) efforts following Hurricane Harvey in 2017 to launch DR2 activities following the Intercontinental Terminals Company (ITC) fire in Deer Park, Texas, in 2019. METHODS: A multidisciplinary group of academic, community, and government partners launched a myriad of DR2 activities. RESULTS: The DR2 response to Hurricane Harvey focused on enhancing environmental health literacy around clean-up efforts, measuring environmental contaminants in soil and water in impacted neighborhoods, and launching studies to evaluate the health impact of the disaster. The lessons learned after Harvey enabled rapid DR2 activities following the ITC fire, including air monitoring and administering surveys and in-depth interviews with affected residents. CONCLUSIONS: Embedding DR2 activities at academic institutions can enable rapid deployment of lessons learned from one disaster to enhance the response to subsequent disasters, even when those disasters are different. Our experience demonstrates the importance of academic institutions working with governmental and community partners to support timely disaster response efforts. Efforts enabled by such experience include providing health and safety training and consistent and reliable messaging, collecting time-sensitive and critical data in the wake of the event, and launching research to understand health impacts and improve resiliency.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India.

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

Mechanistic transmission modeling of COVID-19 on the Diamond Princess cruise ship demonstrates the importance of aerosol transmission.

Several lines of existing evidence support the possibility of airborne transmission of coronavirus disease 2019 (COVID-19). However, quantitative information on the relative importance of transmission pathways of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains limited. To evaluate the relative importance of multiple transmission routes for SARS-CoV-2, we developed a modeling framework and leveraged detailed information available from the Diamond Princess cruise ship outbreak that occurred in early 2020. We modeled 21,600 scenarios to generate a matrix of solutions across a full range of assumptions for eight unknown or uncertain epidemic and mechanistic transmission factors. A total of 132 model iterations met acceptability criteria (R2 > 0.95 for modeled vs. reported cumulative daily cases and R2 > 0 for daily cases). Analyzing only these successful model iterations quantifies the likely contributions of each defined mode of transmission. Mean estimates of the contributions of short-range, long-range, and fomite transmission modes to infected cases across the entire simulation period were 35%, 35%, and 30%, respectively. Mean estimates of the contributions of larger respiratory droplets and smaller respiratory aerosols were 41% and 59%, respectively. Our results demonstrate that aerosol inhalation was likely the dominant contributor to COVID-19 transmission among the passengers, even considering a conservative assumption of high ventilation rates and no air recirculation conditions for the cruise ship. Moreover, close-range and long-range transmission likely contributed similarly to disease progression aboard the ship, with fomite transmission playing a smaller role. The passenger quarantine also affected the importance of each mode, demonstrating the impacts of the interventions.

The Relationship between Nature Deprivation and Individual Wellbeing across Urban Gradients under COVID-19.

Lockdown aiming at slowing COVID-19 transmission has altered nature accessibility patterns, creating quasi-experimental conditions to assess if retracted nature contact and perceived nature deprivation influence physical and emotional wellbeing. We measure through on-line survey methods (n = 529) how pandemic mandates limiting personal movement and outdoor nature access within the United States affect self-assessed nature exposure, perceived nature deprivation, and subsequent flourishing as measured by the Harvard Flourishing Index. Results indicate that perceived nature deprivation strongly associates with local nature contact, time in nature, and access to municipal nature during the pandemic, after controlling for lockdown mandates, job status, household composition, and sociodemographic variables. Our hypothesis is that individuals with strong perceived nature deprivation under COVID-19 leads to diminished wellbeing proved true. Interaction models of flourishing showed positive modification of nature affinity with age and qualitative modification of nature deprivation with race. Our results demonstrate the potential of local nature contact to support individual wellbeing in a background context of emotional distress and social isolation, important in guiding public health policies beyond pandemics.

An Unrecognized Hazard in E-Cigarette Vapor: Preliminary Quantification of Methylglyoxal Formation from Propylene Glycol in E-Cigarettes.

Up to 95% of the liquid volume in an e-cigarette consists of propylene glycol. Previous research has shown that propylene glycol can generate diacetyl and formaldehyde when heated. New research shows that propylene glycol can also generate methylglyoxal, an alpha di-carbonyl compound recently shown to cause epithelial necrosis at even lower concentrations than diacetyl, the flavoring chemical associated with bronchiolitis obliterans ("Popcorn Lung"). We analyzed chemical emissions from 13 JUUL pod flavors. Diacetyl and methylglyoxal was detected in 100% of samples with median concentration (range) of 20 µg/m3 (less than limit of quantification: 54 µg/m3) and 4219 µg/m3 (677-15,342 µg/m3), respectively. We also detected acetaldehyde (median concentration: 341 µg/m3) and propionaldehyde (median concentration: 87 µg/m3) in all samples. The recent evidence that methylglyoxal is more cytotoxic to airway epithelial cells than diacetyl makes this an urgent public health concern. Current smokers considering e-cigarettes as a smoking cessation tool, and never users, who may be under the impression that e-cigarettes are harmless, need information on emissions and potential risks to make informed decisions.

Real-time indoor PM2.5 monitoring in an urban cohort: Implications for exposure disparities and source control.

Fine particulate matter (PM2.5) concentrations are highly variable indoors, with evidence for exposure disparities. Real-time monitoring coupled with novel statistical approaches can better characterize drivers of elevated PM2.5 indoors. We collected real-time PM2.5 data in 71 homes in an urban community of Greater Boston, Massachusetts using Alphasense OPC-N2 monitors. We estimated indoor PM2.5 concentrations of non-ambient origin using mass balance principles, and investigated their associations with indoor source activities at the 0.50 to 0.95 exposure quantiles using mixed effects quantile regressions, overall and by homeownership. On average, the majority of indoor PM2.5 concentrations were of non-ambient origin (≥77%), with a higher proportion at increasing quantiles of the exposure distribution. Major source predictors of non-ambient PM2.5 concentrations at the upper quantile (0.95) were cooking (1.4-23 µg/m3) and smoking (15 µg/m3, only among renters), with concentrations also increasing with range hood use (3.6 µg/m3) and during the heating season (5.6 µg/m3). Across quantiles, renters in multifamily housing experienced a higher proportion of PM2.5 concentrations from non-ambient sources than homeowners in single- and multifamily housing. Renters also more frequently reported cooking, smoking, spray air freshener use, and second-hand smoke exposure, and lived in units with higher air exchange rate and building density. Accounting for these factors explained observed PM2.5 exposure disparities by homeownership, particularly in the upper exposure quantiles. Our results suggest that renters in multifamily housing may experience higher PM2.5 exposures due to a combination of behavioral and building factors that are amenable to intervention.

Green, Brown, and Gray: Associations between Different Measurements of Land Patterns and Depression among Nursing Students in El Paso, Texas.

BACKGROUND: While greenness has been associated with lower depression, the generalizability of this association in arid landscapes remains undetermined. We assessed the association between depression and residential greenness, but also brownness and grayness among nursing students living in El Paso, Texas (the Chihuahuan desert). METHODS: Depression was measured with the Patient Health Questionnaire-9 scale and greenness with the normalized difference vegetation index across three buffer sizes (i.e., 250, 500, and 1000 m). Using data from the National Land Cover Database, two additional measures of land patterns were analyzed: grayness and brownness. Structural equation models were used to assess the relationships of these land patterns to depression and quantify the indirect effects of peer alienation. RESULTS: After adjusting for individual characteristics, at buffers 250 m, greenness was not associated with a decrease in the Incidence Rate Ratios (IRR) of depression (IRR, 0.51; 95% CI, 0.12-2.10); however, grayness and brownness were respectively associated with increases by 64% (IRR, 1.64; 95% CI, 1.07-2.52) and decreases by 35% (IRR, 0.65; 95% CI, 0.42-0.99). At buffer 250 m, peer alienation explained 17.43% (95% CI, -1.79-36.66) of the association between depression and brownness, suggesting a pathway to depression. CONCLUSIONS: We did not observe an association between depression and residential greenness in El Paso, Texas. However, we did observe a protective association between brownness and depression and an adverse association with grayness. These results have theoretical implications as they were based on commonly used frameworks in this literature, and adverse association of brownness (and the lack of greenness) and depression was expected.

Estimating the nationwide transmission risk of measles in US schools and impacts of vaccination and supplemental infection control strategies.

BACKGROUND: The spread of airborne infectious diseases such as measles is a critical public health concern. The U.S. was certified measles-free in 2000, but the number of measles cases has increased in recent years breaking the record of the nationwide annual number of cases since 1992. Although the characteristics of schools have made them one of the most vulnerable environments during infection outbreaks, the transmission risk of measles among students is not completely understood. We aimed to evaluate how three factors influence measles transmission in schools: personal (vaccination), social (compartmentalizing), and building systems (ventilation, purification, and filtration). METHODS: We used a combination of a newly developed multi-zone transient Wells-Riley approach, a nationwide representative School Building Archetype (SBA) model, and a Monte-Carlo simulation to estimate measles risk among U.S. students. We compared our risk results with the range of reported transmission rates of measles in school outbreaks to validate the risk model. We also investigated the effectiveness of vaccination and ten supplemental infection control scenarios for reducing the risk of measles transmission among students. RESULTS: Our best nationwide estimate of measles transmission risk in U.S. schools were 3.5 and 32% among all (both unvaccinated and immunized) and unvaccinated students, respectively. The results showed the transmission risk of measles among unvaccinated students is > 70 times higher than properly immunized ones. We also demonstrated that the transmission risk of measles in primary schools (assuming teacher self-contained classrooms) is less than secondary schools (assuming departmentalized systems). For building-level interventions, schools with ductless-with-air-filter and ductless-without-air-filter systems have the lowest and highest transmission risks of measles, respectively. Finally, our simulation showed that infection control strategies could cut the average number of infected cases among all students in half when a combination of advanced air filtration, ventilation, and purification was adopted in the modeled schools. CONCLUSIONS: Our results highlight the primary importance of vaccination for reducing the risk of measles transmission among students. Yet, additional and significant risk reduction can be achieved through compartmentalizing students and enhancing building ventilation and filtration systems.

Correction to: Estimating the nationwide transmission risk of measles in US schools and impacts of vaccination and supplemental infection control strategies.

An amendment to this paper has been published and can be accessed via the original article.

Correction to: Response to "A critical look at 'Energy savings, emissions reductions, and health co-benefits of the green building movement'".

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Heart Rate Variability and Performance of Commercial Airline Pilots during Flight Simulations.

Pilots undergo a variety of stressors that may affect their performance during all phases of flight. Heart rate variability (HRV) has been considered as a reliable indicator of the parasympathetic and sympathetic activities of human autonomic nervous system, which can be used to characterize the sympathetic stress response of pilots during flight. In this study, thirty active commercial airline pilots were recruited to fly three flight segments in a Federal Aviation Administration (FAA)-certified A320 flight simulator with each segment at a different carbon dioxide (CO2) concentration on the flight deck. The pilots performed a series of maneuvers of varying difficulty, and their performance was evaluated by FAA designated pilot examiners. The HRV metrics (SDNN, RMSSD and LF/HF ratio) of each pilot both before and during flight simulations were measured with a Movisens EcgMove3 sensor. The average SDNN, RMSSD and LF/HF ratio of the pilots during flight simulations were 34.1 ± 12.7 ms, 23.8 ± 10.2 ms and 5.7 ± 2.8 respectively. Decreased HRV was associated with aging, obesity and performing difficult maneuvers. Both CO2 exposure and HRV had an independent effect on the pilot performance, while their interaction was not significant. The generalized additive mixed effect model results showed that a pilot performed better on a maneuver when his stress response was lower, as indicated by higher SDNN and RMSSD and lower LF/HF ratio. An interquartile range (IQR) increase in SDNN (21.97 ms) and RMSSD (16.00 ms) and an IQR decrease in LF/HF ratio (4.69) was associated with an increase in the odds of passing a maneuver by 37%, 22% and 20%, respectively.

Airplane pilot flight performance on 21 maneuvers in a flight simulator under varying carbon dioxide concentrations.

BACKGROUND: Recent studies suggest that carbon dioxide has an impact on cognitive function performance of office workers at concentrations previously thought to be benign (1000-2500 ppm). The only available data for CO2 on the flight deck indicate that the average CO2 concentrations are typically <1000 ppm, but the 95th percentile concentration can be as high as 1400 ppm, depending on airplane type. METHODS: We recruited 30 active commercial airline pilots to fly three 3-h flight segments in an FAA-approved flight simulator with each segment at a different CO2 concentration on the flight deck (700, 1500, 2500 ppm). CO2 concentrations were modified by introducing ultra-pure CO2 into the simulator; ventilation rates remained the same for each segment. The pilots performed a range of predefined maneuvers of varying difficulty without the aid of autopilot, and were assessed by a FAA Designated Pilot Examiner according to FAA Practical Test Standards. Pilots and the Examiner were blinded to test conditions and the order of exposures was randomized. RESULTS: Compared to segments at a CO2 concentration of 2500 ppm, the odds of passing a maneuver as rated by the Examiner in the simulator were 1.52 (95% CI: 1.02-2.25) times higher when pilots were exposed to 1500 ppm and 1.69 (95% CI: 1.11-2.55) times higher when exposed to 700 ppm, controlling for maneuver difficulty, Examiner and order of maneuvers. DISCUSSION: Examiner rating captured a wider range of performance indicators than output from the flight simulator, which can characterize only a few quantitative aspects of the flight performance. More broadly, these findings suggest that there is a direct effect of carbon dioxide on performance, independent of ventilation, with implications for many other indoor environments that routinely experience CO2 concentrations above 1000 ppm.

Reduced cognitive function during a heat wave among residents of non-air-conditioned buildings: An observational study of young adults in the summer of 2016.

BACKGROUND: In many regions globally, buildings designed for harnessing heat during the cold exacerbate thermal exposures during heat waves (HWs) by maintaining elevated indoor temperatures even when high ambient temperatures have subdued. While previous experimental studies have documented the effects of ambient temperatures on cognitive function, few have observed HW effects on indoor temperatures following subjects' habitual conditions. The objective was to evaluate the differential impact of having air conditioning (AC) on cognitive function during a HW among residents of AC and non-AC buildings using a prospective observational cohort study. METHODS: We followed 44 students (mean age = 20.2 years; SD = 1.8 years) from a university in the Greater Boston area, Massachusetts in the United States living in AC (n = 24) and non-AC (n = 20) buildings before, during, and after a HW. Two cognition tests were self-administered daily for a period of 12 days (July 9-July 20, 2016), the Stroop color-word test (STROOP) to assess selective attention/processing speed and a 2-digit, visual addition/subtraction test (ADD) to evaluate cognitive speed and working memory. The effect of the HW on cognitive function was evaluated using difference-in-differences (DiD) modelling. FINDINGS: Mean indoor temperatures in the non-AC group (mean = 26.3°C; SD = 2.5°C; range = 19.6-30.4°C) were significantly higher (p < 0.001) than in the AC group (mean = 21.4°C; SD = 1.9°C; range = 17.5-25.0°C). DiD estimates show an increase in reaction time (STROOP = 13.4%, p < 0001; ADD = 13.3%, p < 0.001) and reduction in throughput (STROOP = -9.9%, p < 0.001; ADD = -6.3%, p = 0.08) during HWs among non-AC residents relative to AC residents at baseline. While ADD showed a linear relationship with indoor temperatures, STROOP was described by a U-shaped curve with linear effects below and above an optimum range (indoor temperature = 22°C-23°C), with an increase in reaction time of 16 ms/°C and 24 ms/°C for STROOP and ADD, respectively. Cognitive tests occurred right after waking, so the study is limited in that it cannot assess whether the observed effects extended during the rest of the day. Although the range of students' ages also represents a limitation of the study, the consistent findings in this young, healthy population might indicate that greater portions of the population are susceptible to the effects of extreme heat. CONCLUSIONS: Cognitive function deficits resulting from indoor thermal conditions during HWs extend beyond vulnerable populations. Our findings highlight the importance of incorporating sustainable adaptation measures in buildings to preserve educational attainment, economic productivity, and safety in light of a changing climate.

Flame Retardant Chemicals in College Dormitories: Flammability Standards Influence Dust Concentrations.

Furniture flammability standards are typically met with chemical flame retardants (FRs). FRs can migrate out of products into dust and are linked to cancer, neurological impairment, and endocrine disruption. We collected 95 dust samples from dormitory common areas and student rooms on two U.S. college campuses adhering to two different furniture flammability standards: Technical Bulletin 117 (TB117) and Technical Bulletin 133 (TB133). Because TB133 requires furniture to withstand a much-more-demanding test flame than TB117, we hypothesized that spaces with TB133 furniture would have higher levels of FRs in dust. We found all 47 targeted FRs, including 12 polybrominated diphenyl ether (PBDE) congeners, 19 other brominated FRs, 11 phosphorus FRs (PFRs), 2 Dechlorane-Plus (DP) isomers, and 3 hexabromocyclododecane (HBCDD) isomers in the 95 dust samples. We measured the highest reported U.S. concentrations for a number of FRs, including BDE 209 (up to 990 000 ng/g), which may be used to meet the TB133 standard. We prioritized 16 FRs and analyzed levels in relation to flammability standard as well as presence and age of furniture and electronics. Adherence to TB133 was associated with higher concentrations of BDE 209, decabromodiphenylethane (DBDPE), DPs, and HBCDD compared to adherence to TB117 in univariate models (p < 0.05). Student dormitory rooms tended to have higher levels of some FRs compared to common rooms, likely a result of the density of furniture and electronics. As flammability standards are updated, it is critical to understand their impact on exposure and health risks.