Nasal oxidative stress mediating the effects of colder temperature exposure on pediatric asthma symptoms.

BACKGROUND: Colder temperature exposure is a known trigger for pediatric asthma exacerbation. The induction of oxidative stress is a known pathophysiologic pathway for asthma exacerbation. However, the role of oxidative stress in linking colder temperature exposure and worsened pediatric asthma symptoms is poorly understood. METHODS: In a panel study involving 43 children with asthma, aged 5-13 years old, each child was visited 4 times with a 2-week interval. At each visit, nasal fluid, urine, and saliva samples were obtained and measured for biomarkers of oxidative stress in the nasal cavity (nasal malondialdehyde [MDA]), the circulatory system (urinary MDA), and the oral cavity (salivary MDA). Childhood Asthma-Control Test (CACT) was used to assess asthma symptoms. RESULTS: When ambient daily-average temperature ranged from 7 to 18 °C, a 2 °C decrement in personal temperature exposures were significantly associated with higher nasal MDA and urinary MDA concentrations by 47-77% and 6-14%, respectively. We estimated that, of the decrease in child-reported CACT scores (indicating worsened asthma symptoms and asthma control) associated with colder temperature exposure, 14-57% were mediated by nasal MDA. CONCLUSION: These results suggest a plausible pathway that colder temperature exposure worsens pediatric asthma symptoms partly via inducing nasal oxidative stress. IMPACT: The role of oxidative stress in linking colder temperature exposure and worsened asthma symptoms is still poorly understood. Lower temperature exposure in a colder season was associated with higher nasal and systemic oxidative stress in children with asthma. Nasal MDA, a biomarker of nasal oxidative stress, mediated the associations between colder temperature exposures and pediatric asthma symptoms. The results firstly suggest a plausible pathway that colder temperature exposure worsens pediatric asthma symptoms partly via inducing oxidative stress in the nasal cavity.

"They start on the zero-alcohol and they wanna try the real thing": Parents' views on zero-alcohol beverages and their use by adolescents.

OBJECTIVE: Zero-alcohol beverages containing 0.0-0.5% alcohol by volume may offer public health benefits if individuals use them to substitute for alcohol-containing products, thereby reducing alcohol use. There are, however, concerns that zero-alcohol beverages may encourage adolescents' earlier interest in alcohol and increase exposure to alcohol company branding. As this poses a challenge for parents, we studied parents' views on zero-alcohol beverages and their provision to adolescents. METHODS: We interviewed n=38 parents of 12-17-year-olds and used reflexive thematic analysis to interpret interview data. RESULTS: Parents considered zero-alcohol beverages to be 'adult beverages' that potentially supported reduced adult drinking but were unnecessary for adolescents. Parents were concerned that adolescent zero-alcohol beverage use could normalise alcohol consumption and be a precursor to alcohol initiation. There was a potential conflict between moderate provision in 'appropriate' contexts, and potential benefits, which were each supported by some parents. Uncertainty on health qualities was also reported. CONCLUSIONS: Parents reported conflicting and cautious views on zero-alcohol beverage provision to adolescents. IMPLICATIONS FOR PUBLIC HEALTH: As evidence on the impacts of zero-alcohol beverage availability develops, parent-targeted messages highlighting the potential risk of normalisation of alcohol use for young people could be developed, in conjunction with broader policy responses.

Which parents provide zero-alcohol beverages to adolescents? A survey of Australian parents' practices and intentions.

OBJECTIVE: Zero-alcohol beverages (<0.5% alcohol by volume) appear and taste similar to alcoholic beverages but are regulated similarly to soft drinks in many countries, blurring the distinction between alcoholic and non-alcoholic beverages. How parents view provision of zero-alcohol beverages to adolescents is likely a key determinant of adolescent consumption. We investigated factors associated with parents' provision of zero-alcohol beverages to adolescents, including attitudes toward zero-alcohol beverages and demographic, knowledge, and behavioural factors known to be associated with provision of alcoholic beverages. METHODS: We conducted an online cross-sectional survey of N = 1197 Australian parents of adolescents aged 12-17 years in April-May 2022. We examined associations with zero-alcohol beverage provision using binomial logistic regression, and with future provision intentions using multinomial logistic regression analyses. RESULTS: Factors significantly associated (p < .001) with parents' provision and future intentions to provide zero-alcohol beverages to their adolescent included beliefs that zero-alcohol beverages had benefits for adolescents (Adjusted Odds Ratio [AOR] 2.69 (provision); 3.72 (intentions)), provision of alcoholic beverages (AOR 2.67 (provision); 3.72 (intentions)), and an incorrect understanding of alcohol guidelines for adolescents (AOR 2.38 (provision); 1.95 (intentions)). CONCLUSIONS: Parents' provision and intentions to provide zero-alcohol beverages were associated with beliefs about zero-alcohol beverages as well as some factors associated with provision of alcoholic beverages. Precautionary advice to parents that the provision of zero-alcohol beverages may serve to normalise alcohol consumption may be warranted.

Associations between personal apparent temperature exposures and asthma symptoms in children with asthma.

Ambient temperature and relative humidity can affect asthma symptoms. Apparent temperature is a measure of temperature perceived by humans that takes into account the effect of humidity. However, the potential link between personal exposures to apparent temperature and asthma symptoms has not been investigated. We conducted a panel study of 37 asthmatic children, aged 5-11 years, during an early spring season (average daily ambient temperature: 14°C, range: 7-18°C). Asthma symptoms were measured 4 times for each participant with a 2-week interval between consecutive measurements using the Childhood Asthma-Control Test (C-ACT). Average, minimum, and maximum personal apparent temperature exposures, apparent temperature exposure variability (TV), and average ambient temperature were calculated for the 12 hours, 24 hours, week, and 2 weeks prior to each visit. We found that a 10°C lower in 1-week and 2-week average & minimum personal apparent temperature exposures, TV, and average ambient temperature exposures were significantly associated with lower total C-ACT scores by up to 2.2, 1.4, 3.3, and 1.4 points, respectively, indicating worsened asthma symptoms. Our results support that personal apparent temperature exposure is potentially a stronger driver than ambient temperature exposures for the variability in asthma symptom scores. Maintaining a proper personal apparent temperature exposure could be an effective strategy for personalized asthma management.

Association between spill-related exposure to fine particulate matter and peripheral motor and sensory nerve function among oil spill response and cleanup workers following the Deepwater Horizon oil spill.

BACKGROUND: Burning/flaring of oil/gas during the Deepwater Horizon oil spill response and cleanup (OSRC) generated high concentrations of fine particulate matter (PM2.5). Personnel working on the water during these activities may have inhaled combustion products. Neurologic effects of PM2.5 have been reported previously but few studies have examined lasting effects following disaster exposures. The association of brief, high exposures and adverse effects on sensory and motor nerve function in the years following exposure have not been examined for OSRC workers. OBJECTIVES: We assessed the relationship between exposure to burning/flaring-related PM2.5 and measures of sensory and motor nerve function among OSRC workers. METHODS: PM2.5 concentrations were estimated from Gaussian plume dispersion models and linked to self-reported work histories. Quantitative measures of sensory and motor nerve function were obtained 4-6 years after the disaster during a clinical exam restricted to those living close to two clinics in Mobile, AL or New Orleans, LA (n = 3401). We obtained covariate data from a baseline enrollment survey and a home visit, both in 2011-2013. The analytic sample included 1186 participants. RESULTS: We did not find strong evidence of associations between exposure to PM2.5 and sensory or motor nerve function, although there was a suggestion of impairment based on single leg stance among individuals with high exposure to PM2.5. Results were generally consistent whether we examined average or cumulative maximum exposures or removed individuals with the highest crude oil exposures to account for co-pollutant confounding. There was no evidence of exposure-response trends. IMPACT STATEMENT: Remediating environmental disasters is essential for long-term human and environmental health. During the Deepwater Horizon oil spill disaster, burning and flaring of oil and gas were used to remove these pollutants from the environment, but led to potentially high fine particulate matter exposures for spill response workers working on the water. We investigate the potential adverse effects of these exposures on peripheral nerve function; understanding the potential health harm of remediation tactics is necessary to inform future clean up approaches and protect human health.

Oral cavity response to air pollutant exposure and association with pulmonary inflammation and symptoms in asthmatic children.

Exposure to fine particulate matter (PM2.5) and ozone (O3) may lead to inflammation and oxidative damage in the oral cavity, which is hypothesized to contribute to the worsening of airway inflammation and asthma symptoms. In this panel study of 43 asthmatic children aged 5-13 years old, each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, saliva samples were collected and subsequently analyzed for interleukin 6 (IL-6) and eosinophil cationic protein (ECP) as biomarkers of inflammation and malondialdehyde (MDA) as a biomarker of oxidative stress in the oral cavity. At each visit, children were measured for fractional exhaled nitric oxide (FeNO) as a marker of pulmonary inflammation. Asthma symptoms of these children were measured using the Childhood Asthma Control Test (C-ACT). We found that an interquartile range (IQR) increase in 24-h average personal exposure to PM2.5 measured 1 and 2 days prior was associated with increased salivary IL-6 concentration by 3.0% (95%CI: 0.2%-6.0%) and 4.2% (0.7%-8.0%), respectively. However, we did not find a clear association between personal O3 exposure and any of the salivary biomarkers, except for a negative association between salivary MDA and O3 exposure measured 1 day prior. An IQR increase in salivary IL-6 concentration was associated with significantly increased FeNO by 28.8% (4.3%-53.4%). In addition, we found that increasing salivary IL-6 concentrations were associated with decreased individual and total C-ACT scores, indicating the worsening of asthma symptoms. We estimated that 13.2%-22.2% of the associations of PM2.5 exposure measured 1 day prior with FeNO and C-ACT scores were mediated by salivary IL-6. These findings suggest that the induction of inflammation in the oral cavity may have played a role in linking air pollution exposure with the worsening of airway inflammation and asthma symptoms.

The validity of the science teacher efficacy belief instrument (STEBI-B) for postgraduate, pre-service, primary teachers.

The STEBI-B (Enoch and Riggs, 1990) has been widely used as a measure of undergraduate primary pre-service teacher self-efficacy since its creation. However, the publication of its use within postgraduate teaching courses has been limited. The postgraduate pre-service teachers (Graduate Diploma and Master of Education students) are a very different population, presenting with more life experience and importantly, more experience in Science. This brings the generalizability of the STEBI-B to this population into question. The validity of the STEBI-B for use with a postgraduate, pre-service teacher population was investigated using a Rasch model analysis. Results support the two-factor structure presented by the original authors, the rewording proposed by Bleicher (2004), and additional modifications to the Likert scale and wording to improve targeting for this specific population. With simple, justified modifications the STEBI-B can be used as a tool to positively influence course design in postgraduate, pre-service teacher, science education courses.

Role of endogenous melatonin in pathophysiologic and oxidative stress responses to personal air pollutant exposures in asthmatic children.

BACKGROUND: Heightening oxidative stress and inflammation is an important pathophysiological mechanism underlying air pollution health effects in people with asthma. Melatonin can suppress oxidative stress and inflammation in pulmonary and circulatory systems. However, the role of melatonin in the oxidative stress and physiological responses to air pollution exposure has not been examined in children with asthma. METHODS: In this panel study of 43 asthmatic children (5-13 years old), each child had 4 clinic visits with a 2-week interval between two consecutive visits. At each visit, urine samples were collected and subsequently analyzed for 6-sulfatoxymelatonin (aMT6s) as a surrogate of circulating melatonin and for malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as two biomarkers of systemic oxidative stress. At each clinic visit, children were measured for pulmonary function and fractional exhaled nitric oxide (FeNO, a marker of pulmonary inflammation). None of the children reported to have taking melatonin supplementation. Concentrations of indoor and ambient PM2.5 and ozone (O3) were combined with individual time-activity data to calculate personal air pollutant exposures. RESULTS: We found that interquartile range increases in urinary MDA and 8-OHdG concentrations were associated with significantly increased urinary aMT6s concentrations by 73.4% (95% CI: 52.6% to 97.0%) and 41.7% (22.8% to 63.4%), respectively. Increases in daily personal exposure to O3 and to PM2.5 were each associated with increased urinary aMT6s concentrations. Increasing urinary aMT6s concentrations were associated with decreased FeNO and resonant frequency, indicating improved airway inflammation and lung elasticity, respectively. CONCLUSION: The results suggest that systemic oxidative stress heightened by air pollution exposure may stimulate melatonin excretion as a defense mechanism to alleviate the adverse effects.

Care of Older People in Surgery for general surgery: a single centre experience.

BACKGROUND: Older patients undergoing emergency surgery experience higher mortality and morbidity. 'Care of Older People in Surgery' (COPS) is a comprehensive geriatric care model developed for acute surgical units (ASU) to improve clinical outcomes in older general surgical patients. This study aimed to evaluate the impact of COPS on clinical and health service outcomes in an Australian hospital. METHODS: The before-and-after study was conducted in the ASU, at Nepean Hospital. Data from patients ≥75 years admitted for >24 h into the ASU during the intervention period between April 2017 and March 2018 were compared to patients admitted in the previous year (April 2016 to March 2017) prior to the COPS intervention (n = 212). Health service outcomes measured include the average stay length, medical emergency team response, unplanned intensive care unit admission and 28-day readmission rates. RESULTS: The COPS group (n = 214) suffered significantly fewer medical complications, including less acute kidney injuries, arrhythmias and urinary tract infections compared to the pre-intervention cohort (n = 212). Medical emergency team activation was significantly reduced after COPS model implementation and the average length of stay decreased. However, the incidence of postoperative delirium and acute coronary syndrome were higher in COPS cohort. CONCLUSION: Our study demonstrated that comprehensive geriatric assessment and care delivered through a shared model of care in older general surgical patients improved clinical outcome and patient safety measures.

Personal Exposure to PM2.5 Oxidative Potential in Association with Pulmonary Pathophysiologic Outcomes in Children with Asthma.

Fine particulate matter (PM2.5) with a higher oxidative potential has been thought to be more detrimental to pulmonary health. We aim to investigate the associations between personal exposure to PM2.5 oxidative potential and pulmonary outcomes in asthmatic children. We measured each of the 43 asthmatic children 4 times for airway mechanics, lung function, airway inflammation, and asthma symptom scores. Coupling measured indoor and outdoor concentrations of PM2.5 mass, constituents, and oxidative potential with individual time-activity data, we calculated 24 h average personal exposures 0-3 days prior to a health outcome measurement. We found that increases in daily personal exposure to PM2.5 oxidative potential were significantly associated with increased small, large, and total airway resistance, increased airway impedance, decreased lung function, and worsened scores of individual asthma symptoms and the total symptom score. Among the PM2.5 constituents, organic matters largely of indoor origin contributed the greatest to PM2.5 oxidative potential. Given that the variability in PM2.5 oxidative potential was a stronger driver than PM2.5 mass for the variability in the respiratory health outcomes, it is suggested to reduce PM2.5 oxidative potential, particularly by reducing the organic matter constituent of indoor PM2.5, as a targeted source control strategy in asthma management.

The Prognostic Performance of Frailty for Delirium and Functional Decline in Vascular Surgery Patients.

BACKGROUND: Frailty in older vascular surgery patients is associated with increased mortality, hospital stay, and morbidity. The association of frailty with hospital-acquired geriatric syndromes such as delirium and functional decline has not been well studied. OBJECTIVES: To investigate the association between frailty and hospital-acquired geriatric syndromes in older hospitalized vascular surgery patients, and to evaluate the prognostic performance of the frailty index (FI) and the Clinical Frailty Scale (CFS) for delirium and functional decline. DESIGN: Prospective cohort study. SETTING: Acute care academic hospital. PARTICIPANTS: Patients aged 65 years or more admitted to a tertiary vascular surgery unit (N=150). MEASUREMENTS: Frailty was assessed using the FI and CFS. The adjusted association of frailty status with delirium and functional decline was assessed using logistic regression analysis. The prognostic performance of FI and CFS was determined by assessing C-statistic and positive and negative predictive values (PPV and NPV). RESULTS: Of 150 participants, FI identified 34 (23%) and CFS identified 45 (30%) as frail. Frailty was an independent predictor of delirium (FI adjusted odds ratio, odds ratio (OR) = 5.66, 95% confidence interval (CI) = 1.53-21.03; CFS adjusted OR = 4.07, 95% CI = 1.14-14.50), but not functional decline. FI and CFS showed acceptable prognostic performance for delirium (C-statistic 0.74), but not functional decline (C-statistic 0.63-0.64). For both outcomes, the FI and CFS had high NPV (86-96%), and low PPV (22-29%). CONCLUSION: Frail older vascular surgery patients are more likely to develop hospital-acquired geriatric syndromes. The FI and CFS have acceptable prognostic performance for predicting delirium but not all individuals who are identified as frail develop delirium. Ongoing research is needed to identify interventions that improve outcomes in patients who screen positive for frailty.

Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes.

Portable air cleaners are increasingly used in polluted areas in an attempt to reduce human exposure; however, there has been limited work characterizing their effectiveness at reducing exposure. With this in mind, we recruited forty-three children with asthma from suburban Shanghai and deployed air cleaners (with HEPA and activated carbon filters) in their bedrooms. During both 2-week filtration and non-filtration periods, low-cost PM2.5 and O3 air monitors were used to measure pollutants indoors, outdoors, and for personal exposure. Indoor PM2.5 concentrations were reduced substantially with the use of air cleaners, from 34 ± 17 to 10 ± 8 µg/m3 , with roughly 80% of indoor PM2.5 estimated to come from outdoor sources. Personal exposure to PM2.5 was reduced from 40 ± 17 to 25 ± 14 µg/m3 . The more modest reductions in personal exposure and high contribution of outdoor PM2.5 to indoor concentrations highlight the need to reduce outdoor PM2.5 and/or to clean indoor air in multiple locations. Indoor O3 concentrations were generally low (mean = 8±4 ppb), and no significant difference was seen by filtration status. The concentrations of pollutants and the air cleaner effectiveness were highly variable over time and across homes, highlighting the usefulness of real-time air monitors for understanding individual exposure reduction strategies.

Does identifying frailty from ICD-10 coded data on hospital admission improve prediction of adverse outcomes in older surgical patients? A population-based study.

BACKGROUND: frailty is a major contributor to poor health outcomes in older people, separate from age, sex and comorbidities. This population-based validation study evaluated the performance of the International Classification of Diseases, 10th revision, coded Hospital Frailty Risk Score (HFRS) in the prediction of adverse outcomes in an older surgical population and compared its performance against the commonly used Charlson Comorbidity Index (CCI). METHODS: hospitalisation and death data for all individuals aged ≥50 admitted for surgery to New South Wales hospitals (2013-17) were linked. HFRS and CCI scores were calculated using both 2- and 5-year lookback periods. To determine the influence of individual explanatory variables, several logistic regression models were fitted for each outcome of interest (30-day mortality, prolonged length of stay (LOS) and 28-day readmission). Area under the receiving operator curve (AUC) and Akaike information criterion (AIC) were assessed. RESULTS: of the 487,197 patients, 6.8% were classified as high HFRS, and 18.3% as high CCI. Although all models performed better than base model (age and sex) for prediction of 30-day mortality, there was little difference between CCI and HFRS in model discrimination (AUC 0.76 versus 0.75), although CCI provided better model fit (AIC 79,020 versus 79,910). All models had poor ability to predict prolonged LOS (AUC range 0.62-0.63) or readmission (AUC range 0.62-0.65). Using a 5-year lookback period did not improve model discrimination over the 2-year period. CONCLUSIONS: adjusting for HFRS did not improve prediction of 30-mortality over that achieved by the CCI. Neither HFRS nor CCI were useful for predicting prolonged LOS or 28-day unplanned readmission.

Children's microenvironmental exposure to PM2.5 and ozone and the impact of indoor air filtration.

BACKGROUND: In highly polluted urban areas, personal exposure to PM2.5 and O3 occur daily in various microenvironments. Identifying which microenvironments contribute most to exposure can pinpoint effective exposure reduction strategies and mitigate adverse health impacts. METHODS: This work uses real-time sensors to assess the exposures of children with asthma (N = 39) in Shanghai, quantifying microenvironmental exposure to PM2.5 and O3. An air cleaner was deployed in participants' bedrooms where we hypothesized exposure could be most efficiently reduced. Monitoring occurred for two 48-h periods: one with bedroom filtration (portable air cleaner with HEPA and activated carbon filters) and the other without. RESULTS: Children spent 91% of their time indoors with the majority spent in their bedroom (47%). Without filtration, the bedroom and classroom environments were the largest contributors to PM2.5 exposure. With filtration, bedroom PM2.5 exposure was reduced by 75% (45% of total exposure). Although filtration status did not impact O3, the largest contribution of O3 exposure also came from the bedroom. CONCLUSIONS: Actions taken to reduce bedroom PM2.5 and O3 concentrations can most efficiently reduce total exposure. As real-time pollutant monitors become more accessible, similar analyses can be used to evaluate new interventions and optimize exposure reductions for a variety of populations.

Malondialdehyde in Nasal Fluid: A Biomarker for Monitoring Asthma Control in Relation to Air Pollution Exposure.

Fine particulate matter (PM2.5) and ozone (O3) may exert oxidative damage in the nose, which is hypothesized to be associated with worsened asthma symptoms. This study, hence, is to explore whether an oxidative stress biomarker, malondialdehyde (MDA) in the nasal fluid, has the potential to aid personalized asthma control. In a panel study of 43 asthmatic children, 5-13 years old, each child was measured 4 times with a 2-week interval between consecutive clinic visits. At each visit, nasal fluid and urine samples were collected, and fractional exhaled nitric oxide (FeNO) was measured as a biomarker of pulmonary inflammation. In addition to nasal MDA, urinary MDA and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured as biomarkers of systemic oxidative stress. We also assessed asthma symptoms using the Childhood Asthma-Control Test (C-ACT). We found that interquartile range (IQR) increases in 24 h average personal PM2.5 exposure (22.2-33.5 µg/m3), estimated 0 to 5 days prior to a clinic visit, were associated with increased nasal MDA concentrations by 38.6-54.9%. Similarly, IQR increases in 24 h average personal O3 exposure (7.7-8.2 ppb) estimated 2 to 4 days prior were associated with increased nasal MDA by 22.1-69.4%. Only increased PM2.5 exposure was associated with increased FeNO. Increased nasal MDA concentration was associated with decreased total and individual C-ACT scores, indicating worsening of asthma symptoms. However, no significant associations were observed between urinary MDA or 8-OHdG and C-ACT scores. The results confirm that oxidative stress plays an important role in linking air pollution exposure and adverse respiratory health effects. These findings support that MDA in the nasal fluid may serve as a useful biomarker for monitoring asthma status, especially in relation to PM2.5 and O3 exposures, two known risk factors of asthma exacerbation.

Prehabilitation for the Frailty Syndrome: Improving Outcomes for Our Most Vulnerable Patients.

Anesthetists are increasingly faced with the challenge of delivering perioperative care to frail older people. Patients with frailty undergoing surgical intervention are at a significantly increased risk of perioperative complications, mortality, and longer length of stay. Moreover, frailty is often associated with multimorbidity and a range of geriatric syndromes including functional dependency, cognitive impairment, and malnutrition which further increases risk and complexity of care. There is a growing body of evidence that prehabilitation-intervention delivered during the preoperative period to improve overall health and function-can improve postoperative outcomes for patients undergoing surgery. However, whether this vulnerable population stand to benefit from prehabilitation is less clear. We review the evidence for prehabilitation for patients with frailty including whether the risks associated with and outcomes from surgery can be modified through comprehensive geriatric assessment.

Association Between Bedroom Particulate Matter Filtration and Changes in Airway Pathophysiology in Children With Asthma.

Importance: Fine particles (particulate matter 2.5 µm [PM2.5]), a ubiquitous air pollutant, can deposit in the small airways that play a vital role in asthma. It appears to be unknown whether the use of a PM2.5 filtration device can improve small airway physiology and respiratory inflammation in children with asthma. Objective: To discover what pathophysiological changes in the small airways are associated with using a PM2.5-removing device in the bedrooms of children with asthma. Design, Setting, and Participants: Children with mild or moderate asthma were enrolled in this double-blind, crossover study. The participants used a true filtration device and a sham filtration device in their bedrooms in a random order for 2 weeks each with a 2-week washout interval. The study was conducted in a suburb of Shanghai, China, during a low-ozone season. Exposures: Ozone and PM2.5 were measured inside bedrooms and outside a window. Main Outcomes and Measures: Impulse oscillometry, spirometry, and fractional exhaled nitric oxide were measured at the beginning and the end of each intervention. Peak expiratory flow was measured twice daily at home. Results: Forty-three children (5-13 years old; 26 boys [60%]) participated. Outdoor 24-hour mean PM2.5 concentrations were moderately high, ranging from 28.6 to 69.8 µg/m3 (median, 53 µg/m3). During true filtration, bedroom PM2.5 concentrations were a mean (SD) of 63.4% (35.9%) lower than during sham filtration. Compared with sham filtration, true filtration was significantly associated with improved airway mechanics, reflected in a 24.4% (95% CI, 11.8%-37.1%) reduction in total airway resistance, a 43.5% (95% CI, 13.7%-73.3%) reduction in small airway resistance, a 22.2% (95% CI, 2.2%-42.2%) reduction in resonant frequency, and a 73.1% (95% CI, 0.3%-145.8%) increase in airway reactance. True filtration was also associated with significant improvements in fractional exhaled nitric oxide (a 27.6% [95% CI, 8.9%-42.4%] reduction) and peak expiratory flow (a 1.6% [95% CI, 0.8%-2.5%] increase). These improvements were significantly associated with bedroom PM2.5 reduction. Improvements in small airway function were nonsignificant (8.4% [95% CI, -1.4% to 18.3%]) in all participants but significant (13.2% [95% CI, 1.2%-25.1%]) in participants without eosinophilic airway inflammation at baseline. No improvements were observed for forced vital capacity, forced expiratory volume during the first second, and the ratio of these in all participants or subgroups. Conclusions and Relevance: Per these results, indoor PM2.5 filtration can be a practical method to improve air flow in an asthmatic lung through improved airway mechanics and function as well as reduced inflammation. This warrants a clinical trial to confirm. Trial Registration: ClinicalTrials.gov Identifier: NCT03282864.

Associations of personal exposure to air pollutants with airway mechanics in children with asthma.

BACKGROUND: The importance of airway mechanics has been increasingly recognized in pediatric asthma. However, no studies have examined responses of airway mechanics to air pollution exposure in asthmatic children. METHODS: In this panel study involving indoor air filtration manipulation that created a large gradient of personal exposure to PM2.5, the airway mechanics and lung function of 43 asthmatic children 5-13 years old in a suburb of Shanghai were measured four times within 3 consecutive months. Concentrations of indoor and outdoor PM2.5 and ozone were coupled with individual time-activity data to calculate personal exposures. Linear mixed effects models were used to examine the relationships of personal exposure with indicators of airway mechanics and lung function, respectively. RESULTS: An interquartile range (IQR) increase in 24-hour average PM2.5 personal exposure (30.3 µg/m3) in the prior day was associated with significant increases in small airway resistance (R5-R20) of 15.8%, total airway resistance (R5) of 6.3%, and airway inflammation (FeNO) of 9.6%. These associations were stronger in children with lower blood eosinophil counts (<450/µL). No significant associations were found between personal PM2.5 exposure and lung function. Low-level ozone exposure (daily maximum 8-hour exposure range 1.1-56.4 ppb) was not significantly associated with any of the outcomes. CONCLUSION: Changes in personal PM2.5 exposure, partly enhanced by air filtration, were associated with significant changes in airway resistance and inflammation in children with asthma. These findings suggest the importance of reducing PM2.5 exposure, via personal air quality management, in improving airflow limitation in the airways, especially the small airways.

The impact of household air cleaners on the oxidative potential of PM2.5 and the role of metals and sources associated with indoor and outdoor exposure.

The health effects associated with human exposure to airborne fine particulate matter (PM2.5) have been linked to the ability of PM2.5 to facilitate the production of excess cellular reactive oxygen species (oxidative potential). Concern about the adverse human health impacts of PM2.5 has led to the increased use of indoor air cleaners to improve indoor air quality, which can be an important environment for PM2.5 exposure. However, the degree to which the oxidative potential of indoor and personal PM2.5 can be influenced by an indoor air cleaner remains unclear. In this study we enrolled 43 children with physician diagnosed asthma in suburban Shanghai, China and collected two paired-sets of 48-h indoor, outdoor, and personal PM2.5 exposure samples. One set of samples was collected under "real filtration" during which a functioning air cleaner was installed in the child's bedroom, and the other ("false filtration") with an air cleaner without internal filters. The PM2.5 samples were characterized by inductively coupled plasma mass spectroscopy for elements, and by an alveolar macrophage assay for oxidative potential. The sources of metals contributing to our samples were determined by the EPA Positive Matrix Factorization model. The oxidative potential was lower under real filtration compared to sham for indoor (median real/sham ratio: 0.260) and personal exposure (0.813) samples. Additionally, the sources of elements in PM2.5 that were reduced indoors and personal exposure samples by the air cleaner (e.g. regional aerosol and roadway emissions) were found by univariate multiple regression models to be among those contributing to the oxidative potential of the samples. An IQR increase in the regional aerosol and roadway emissions sources was associated with a 107% (95% CI: 80.1-138%) and 38.1% (17.6-62.1%) increase in measured oxidative potential respectively. Our results indicate that indoor air cleaners can reduce the oxidative potential of indoor and personal exposure to PM2.5, which may lead to improved human health.