Air pollution, weather and positive airway pressure treatment adherence in adults with sleep apnea: a retrospective community-based repeated-measures longitudinal study.

We assessed the relation between air pollution, weather, and adherence to positive airway pressure (PAP) therapy in a retrospective community-based repeated-measures study of adults with obstructive sleep apnea who purchased PAP devices from a registered provider between 2013 and 2017 (Ottawa, Ontario, Canada) and had at least one day of data. Daily PAP-derived data, air pollution, and weather databases were linked using postal code. The exposures were mean nocturnal (8:00 p.m. to 8:00 a.m.) (i) residential concentrations of nitrogen dioxide (NO2 ), fine particulate matter <=2.5 µm (PM2.5 ), ozone (O3 ), and Air Quality Health Index (AQHI), and (ii) temperature, relative humidity, and barometric pressure. Covariates in the main model were demographics, season, exposure year, and PAP therapy mode. We analysed 8148 adults (median age of 54 years and 61% men) and 2,071,588 days of data. Based on daily data, the median (interquartile range) daily PAP usage was 416 (323-487) min. Using mixed-effect regression analyses to incorporate daily data and clustering by individuals, we found a statistically significant decrease in adherence for increased levels of NO2 , PM2.5 , and AQHI. The largest effect was for NO2 : a decrease in daily PAP use while comparing the highest versus lowest quartiles (Qs) was 3.4 (95% confidence interval [CI] 2.8-3.9) min. Decreased PAP adherence was also associated with increased temperature (Q4 versus Q1: 2.6 [95% CI: 1.5-3.7] min) and decreased barometric pressure (Q1 versus Q4: 2.0 [95% CI 1.5-2.5] min). We observed modest but statistically significant acute effects of air pollution and weather on daily PAP adherence.

The association between the Canadian active living environments index and glucose metabolism in a Canadian national population study.

Biomarkers of glucose metabolism may reflect insulin resistance, a risk factor for diabetes and cardiovascular disease (CVD). Neighborhoods conducive to a physically active lifestyle have the potential to improve these biomarkers. We examined cross-sectional associations between walkability and blood biomarkers of glucose metabolism in 29,649 Canadian Health Measures Survey (CHMS) participants. We used generalized linear mixed models with sampling weights adjusted for province, participants' age, sex, annual household income and educational attainment, cigarette smoking, environmental tobacco smoke, alcohol consumption, and exposure to ambient fine particulate air pollution (PM2.5). A higher value of the Canadian Active Living Environments Index, a measure of neighborhood walkability, equivalent to the magnitude of its interquartile range (IQR) of 2.4 was significantly associated with percentage differences of -0.48 (95% confidence interval (CI): 0.63, -0.32), -3.17 (95%CI: 5.27, -1.08), -3.88 (95%CI: 6.38, -1.38), and -3.36 (95%CI: 5.25, -1.47) in HbA1C, fasting insulin, HOMA-IR, and HOMA-ß, respectively, for all CHMS participants. No significant effects were observed in those ≤16 years old. Canadians living in neighborhoods that facilitate active living have more favorable biomarkers of glucose metabolism, suggesting that the built environment has the potential to improve risk factors for diabetes and CVD in adults.

Do blood metals influence lipid profiles? Findings of a cross-sectional population-based survey.

Dyslipidemia, an imbalance of lipids and a major risk factor for cardiovascular disease, has been associated with elevated blood and urine levels of several heavy metals. Using data from a Canadian Health Measures Survey (CHMS), we tested associations between blood levels of cadmium, copper, mercury, lead, manganese, molybdenum, nickel, selenium, and zinc, and the lipids triglycerides (TG), total cholesterol (TC), low density lipoproteins (LDL), high density lipoproteins (HDL) and apolipoproteins A1 (APO A1), and B (APO B). All adjusted associations between single metals and lipids were positive and significant, except for APO A1 and HDL. The joint effect of an interquartile range increase in heavy metals was positively associated with percentage increases of TC, LDL and APO B of 8.82% (95%CI: 7.06, 10.57), 7.01% (95%CI: 2.51, 11.51) and 7.15% (95%CI: 0.51, 13.78), respectively. Future studies are warranted to determine if reducing environmental exposure to heavy metals favorably influences lipid profiles and the risk of cardiovascular disease.

Activity-related dyspnea in older adults participating in the Canadian Longitudinal Study on Aging.

BACKGROUND: Dyspnea is associated with functional impairment and impaired quality of life. There is limited information on the potential risk factors for dyspnea in an older adult population. OBJECTIVES: Among older adults aged 45 to 85 years of age, what sociodemographic, environmental, and disease related factors are correlated with dyspnea? DESIGN: We used cross-sectional questionnaire data collected on 28,854 participants of the Canadian Longitudinal Study of Aging (CLSA). Multinomial regression was used to assess the independent effect of individual variables adjusting for the other variables of interest. KEY RESULTS: The adjusted odds ratios for dyspnea "walking on flat surfaces" were highest for obesity (OR, 5.71; 95%CI, 4.71-6.93), lung disease (OR, 3.91; 95%CI, 3.41-4.49), and depression (OR, 3.68; 95%CI, 3.15-4.29), and were greater than 2 for lower income, and heart disease. The effect of diabetes remained significant after adjusting for sociodemographics, heart disease and BMI (OR, 1.61; 95%CI, 1.39-1.86). Those with both respiratory disease and depression had a 12.78-fold (95%CI, 10.09-16.19) increased odds of exertional dyspnea, while the corresponding OR for the combination of heart disease and depression was 18.31 (95%CI, 13.4-25.01). CONCLUSIONS: In a community sample of older adults, many correlates of dyspnea exist which have significant independent and combined effects. These factors should be considered in the clinical context where dyspnea is out of proportion to the degree of heart and lung disease. Whether or not diabetes may possibly be a risk factor for dyspnea merits further investigation.

Increased urban greenness associated with improved mental health among middle-aged and older adults of the Canadian Longitudinal Study on Aging (CLSA).

OBJECTIVES: Some studies suggest that residential surrounding greenness is associated with improved mental health. Few of these studies have focussed on middle-aged and older adults, explored the modifying effects of social determinants of health, or accounted for the extent to which individuals interact with their neighbourhood environments. METHODS: We analysed cross-sectional data collected from 26,811 urban participants of the Canadian Longitudinal Study of Aging who were between 45 and 86 years of age. Participants provided details on socioeconomic characteristics, health behaviours, and their frequency of neighbourhood interactions. The Normalized Difference Vegetation Index (NDVI), a measure of greenness, was assigned to participants' residential addresses at a buffer distance of 500 m. Four self-reported measures of mental health were considered: The Center for Epidemiologic Studies Depression Scale (CES-D-10; short scale), past diagnosis of clinical depression, perceptions of mental health, and the Satisfaction with Life Scale (SWLS). Regression models were used to describe associations between greenness and these outcomes, and spline models were fit to characterize the exposure-response function between greenness and CES-D-10 scores. Stratified analyses evaluated whether associations varied by sociodemographic status. RESULTS: In adjusted models, we observed a 5% (Odds Ratio (OR) = 0.95; 95% CI = 0.90, 0.99) reduced odds of depressive symptoms in relation to an interquartile range increase of NDVI (0.06) within a 500 m buffer of the participant's residence. Similarly, we found an inverse association with a self-reported clinical diagnosis of depression (OR = 0.97; 95% CI = 0.92-1.01). Increases in surrounding greenness were associated with improved perceptions of mental health, and the SWLS. Our spline analyses found that beneficial effects between greenness and the CES-D-10 were strongest among those of lower income. CONCLUSIONS: These findings suggest that residential greenness has mental health benefits, and that interventions to increase urban greenness can help reduce social inequalities in mental health.

The association between air pollution and hospitalization for patients with systemic lupus erythematosus in Chile: A daily time series analysis.

Genetic and environmental factors are thought to influence the activity of systemic lupus erythematosus (SLE), but relatively little is known about the effects of ambient air pollution. Using pollution data from air monitoring stations in the urban centers in Santiago Chile, along with daily patient hospitalization data from 2001 to 2012, an association between ambient air pollution and daily hospital admissions for SLE was tested using generalized linear models. Averaged over all regions pollutant mean 24 h concentrations were: 0.96 ppm carbon monoxide (CO), 64 ppb ozone (O3), 43 ppb nitrogen dioxide (NO2), 9 ppb sulphur dioxide (SO2), 29 µg/m3 particulate matter ≤ 2.5 µm in mean aerodynamic diameter (PM2.5), and 67 µg/m3 particulate matter ≤ 10 µm in diameter (PM10). The relative risk estimates in single pollutant models for an interquartile range (IQR) increase in pollutant were: RR = 1.34 (95% CI: 1.06-1.83) for SO2, RR = 1.60 (95% CI: 1.15-2.24) for CO, and RR = 1.41 (95% CI: 1.14-1.86) for PM2.5. In two-pollutant models, the significance of SO2 and PM2.5 persisted despite adjustments for each of the other measured pollutants. These findings suggest that acute increases in air pollution increase the risk of hospitalization with a primary diagnosis of SLE.

The association between air pollution and COVID-19 related mortality in Santiago, Chile: A daily time series analysis.

BACKGROUND: Exposure to ambient air pollution is a risk factor for morbidity and mortality from lung and heart disease. RESEARCH QUESTION: Does short term exposure to ambient air pollution influence COVID-19 related mortality? STUDY DESIGN AND METHODOLOGY: Using time series analyses we tested the association between daily changes in air pollution measured by stationary monitors in and around Santiago, Chile and deaths from laboratory confirmed or suspected COVID-19 between March 16 and August 31, 2020. Results were adjusted for temporal trends, temperature and humidity, and stratified by age and sex. RESULTS: There were 10,069 COVID-19 related deaths of which 7659 were laboratory confirmed. Using distributed lags, the cumulative relative risk (RR) (95% CI) of mortality for an interquartile range (IQR) increase in CO, NO2 and PM2.5 were 1.061 (1.033-1.089), 1.067 (1.023-1.103) and 1.058 (1.034-1.082), respectively There were no significant differences in RR by sex.. In those at least 85 years old, an IQR increase in NO2 was associated with a 12.7% (95% CI 4.2-22.2) increase in daily mortality. CONCLUSION: This study provides evidence that daily increases in air pollution increase the risk of dying from COVID-19, especially in the elderly.

Associations between air pollution and cardio-respiratory physiological measures in older adults exercising outdoors.

We examined whether exercising indoors vs. outdoors reduced the cardio-respiratory effects of outdoor air pollution. Adults ≥55 were randomly assigned to exercise indoors when the Air Quality Health Index was ≥5 and outdoors on other days (intervention group, n = 37), or outdoors everyday (control group, n = 35). Both groups completed cardio-respiratory measurements before and after exercise for up to 10 weeks. Data were analyzed using linear mixed effect regression models. In the control group, an interquartile range increase in fine particulate matter (PM2.5) was associated with increases of 1.4% in heart rate (standard error (SE) = 0.7%) and 5.6% (SE = 2.6%) in malondialdehyde, and decreases of 5.6% (SE = 2.5%) to 16.5% (SE = 7.5%) in heart rate variability measures. While the hypothesized benefit of indoor vs. outdoor exercise could not be demonstrated due to an insufficient number of intervention days (n = 2), the study provides evidence of short-term effects of air pollution in older adults. ISRCTN #26552763.

Effect of industrial point-source air pollutants on fractional exhaled nitric oxide in healthy volunteers.

BACKGROUND: Few studies have examined the effects of industrial, fixed-site sources of air pollution on lung inflammation in nearby residents. We investigated the effects of short-term exposure to ambient air near a steel plant on the fractional exhaled concentration of nitric oxide (FeNO), a measure of airway inflammation, in healthy volunteers. METHODS: A cross-over study design was used. Fifty-nine non-smoking participants (mean age 24 years) were randomly assigned to each of two 5-day exposure scenarios: breathing ambient air adjacent to a steel plant or 5 km away at a college campus site. FeNO and on-site air pollutants were measured daily. Mixed effects linear regression models were used for data analysis, adjusting for sex, temperature, humidity and day of week. RESULTS: Compared with the college site, PM 2.5, ultrafine PM, SO2, NO2 and CO levels were significantly greater near the steel plant. FeNO was 15.3% (95% CI, 6.6%, 24.8%) higher near the plant compared to the college site. CONCLUSIONS: Exposure to ambient air near a steel plant was associated with increased airway inflammation as measured by exhaled nitric oxide.

Do acute changes in ambient air pollution increase the risk of potentially fatal cardiac arrhythmias in patients with implantable cardioverter defibrillators?

BACKGROUND: Daily changes in ambient air pollution have been associated with cardiac morbidity and mortality. Precipitating a cardiac arrhythmia in susceptible individuals may be one mechanism. We investigated the influence of daily changes in air pollution in the Province of Ontario, Canada on the frequency of discharges from implantable cardio defibrillators (ICDs) which occur in response to potentially life threatening arrhythmias. METHODS: Using a case- crossover design, we compared ambient air pollution concentrations on the day of an ICD discharge to other days in the same month and year in 1952 patients. We adjusted for weather, lagged the exposure data from 0 to 3 days, and stratified the results by several patient-related characteristics. RESULTS: Median (interquartile range) for ozone (O3), fine particulate matter (PM2.5), sulphur dioxide (SO2) and nitrogen dioxide (NO2) were 26.0 ppb (19.4, 33.0), 6.6 µg/m3 (4.3, 10.6), 1.00 ppb (0.4,2.1), 10.0 ppb (6.0,15.3) respectively. Unlagged odds ratios (95%) for an ICD discharge associated with an interquartile range increase in pollutant were 0.97 (0.86, 1.09) for O3, 0.99 (0.92, 1.06) for PM2.5, 0.97 (0.91, 1.03) for SO2, and 1.00 (0.89, 1.12) for NO2. CONCLUSION: We found no evidence that the concentrations of ambient air pollution observed in our study were a risk factor for potentially fatal cardiac arrhythmias in patients with ICDs.

Air pollution and emergency department visits for respiratory diseases: A multi-city case crossover study.

Increasing evidence suggests that ambient air pollution is a major risk factor for both acute and chronic respiratory disease exacerbations and emergencies. The objective of this study was to determine the association between ambient air pollutants and emergency department (ED) visits for respiratory conditions in nine districts across the province of Ontario in Canada. Health, air pollutant (PM2.5, NO2, O3, and SO2), and meteorological data were retrieved from April 2004 to December 2011. Respiratory diseases were categorized as: chronic obstructive pulmonary disease (COPD, including bronchiectasis) and acute upper respiratory diseases. A case-crossover design was used to test the associations between ED visits and ambient air pollutants, stratified by sex and season. For COPD among males, positive results were observed for NO2 with lags of 3-6 days, for PM2.5 with lags 1-8, and for SO2 with lags of 4-8 days. For COPD among females, positive results were observed for O3 with lags 2-4 days, and for SO2 among lags of 3-6 days. For upper respiratory disease emergencies among males, positive results were observed for NO2 (lags 5-8 days), for O3, (lags 0-6 days), PM2.5 (all lags), and SO2 (lag 8), and among females, positive results were observed for NO2 for lag 8 days, for O3, PM2.5 among all lags. Our study provides evidence of the associations between short-term exposure to air pollution and increased risk of ED visits for upper and lower respiratory diseases in an environment where air pollutant concentrations are relatively low.

Cardiovascular and inflammatory mechanisms in healthy humans exposed to air pollution in the vicinity of a steel mill.

BACKGROUND: There is a paucity of mechanistic information that is central to the understanding of the adverse health effects of source emission exposures. To identify source emission-related effects, blood and saliva samples from healthy volunteers who spent five days near a steel plant (Bayview site, with and without a mask that filtered many criteria pollutants) and at a well-removed College site were tested for oxidative stress, inflammation and endothelial dysfunction markers. METHODS: Biomarker analyses were done using multiplexed protein-array, HPLC-Fluorescence, EIA and ELISA methods. Mixed effects models were used to test for associations between exposure, biological markers and physiological outcomes. Heat map with hierarchical clustering and Ingenuity Pathway Analysis (IPA) were used for mechanistic analyses. RESULTS: Mean CO, SO2 and ultrafine particles (UFP) levels on the day of biological sampling were higher at the Bayview site compared to College site. Bayview site exposures "without" mask were associated with increased (p < 0.05) pro-inflammatory cytokines (e.g IL-4, IL-6) and endothelins (ETs) compared to College site. Plasma IL-1ß, IL-2 were increased (p < 0.05) after Bayview site "without" compared to "with" mask exposures. Interquartile range (IQR) increases in CO, UFP and SO2 were associated with increased (p < 0.05) plasma pro-inflammatory cytokines (e.g. IL-6, IL-8) and ET-1(1-21) levels. Plasma/saliva BET-1 levels were positively associated (p < 0.05) with increased systolic BP. C-reactive protein (CRP) was positively associated (p < 0.05) with increased heart rate. Protein network analyses exhibited activation of distinct inflammatory mechanisms after "with" and "without" mask exposures at the Bayview site relative to College site exposures. CONCLUSIONS: These findings suggest that air pollutants in the proximity of steel mill site can influence inflammatory and vascular mechanisms. Use of mask and multiple biomarker data can be valuable in gaining insight into source emission-related health impacts.

Exposure to air pollution near a steel plant is associated with reduced heart rate variability: a randomised crossover study.

BACKGROUND: Epidemiological studies have shown that as ambient air pollution (AP) increases the risk of cardiovascular mortality also increases. The mechanisms of this effect may be linked to alterations in autonomic nervous system function. We wished to examine the effects of industrial AP on heart rate variability (HRV), a measure of subtle changes in heart rate and rhythm representing autonomic input to the heart. METHODS: Sixty healthy adults were randomized to spend five consecutive 8-h days outdoors in one of two locations: (1) adjacent to a steel plant in the Bayview neighbourhood in Sault Ste Marie Ontario or (2) at a College campus, several kilometers from the plant. Following a 9-16 day washout period, participants spent five consecutive days at the other site. Ambient AP levels and ambulatory electrocardiogram recordings were collected daily. HRV analysis was undertaken on a segment of the ambulatory ECG recording during a 15 min rest period, near the end of the 8-h on-site day. Standard HRV parameters from both time and frequency domains were measured. Ambient AP was measured with fixed site monitors at both sites. Statistical analysis was completed using mixed-effects models. RESULTS: Compared to the College site, HRV was statistically significantly reduced at the Bayview site by 13% (95%CI 3.6,19.2) for the standard deviation of normal to normal, 8% (95%CI 0.1, 4.9) for the percent normal to normal intervals differing by more than 50 ms, and 15% (95%CI 74.9, 571.2) for low frequency power. Levels of carbon monoxide, sulphur dioxide, nitrogen dioxide, and fine and ultrafine particulates were slightly, but statistically significantly, elevated at Bayview when compared to College. Interquartile range changes in individual air pollutants were significantly associated with reductions in HRV measured on the same day. The patterns of effect showed a high degree of consistency, with nearly all pollutants significantly inversely associated with at least one measure of HRV. CONCLUSIONS: The significant associations between AP and changes in HRV suggest that ambient AP near a steel plant may impact autonomic nervous system control of the heart.

Ambient air pollution exposure and COVID-19 related hospitalizations in Santiago, Chile.

Morbidity and mortality from several diseases are increased on days of higher ambient air pollution. We carried out a daily time-series analysis with distributive lags to study the influence of short-term air pollution exposure on COVID-19 related hospitalization in Santiago, Chile between March 16 and August 31, 2020. Analyses were adjusted for temporal trends, ambient temperature, and relative humidity, and stratified by age and sex. 26,579 COVID-19 hospitalizations were recorded of which 24,501 were laboratory confirmed. The cumulative percent change in hospitalizations (95% confidence intervals) for an interquartile range increase in air pollutants were: 1.1 (0.2, 2.0) for carbon monoxide (CO), 0.30 (0.0, 0.50) for nitrogen dioxide (NO2), and 2.7 (1.9, 3.0) for particulate matter of diameter ≤ 2.5 microns (PM2.5). Associations with ozone (O3), particulate matter of diameter ≤ 10 microns (PM10) and sulfur dioxide (SO2) were not significant. The observed effect of PM2.5 was significantly greater for females and for those individuals ≥ 65 years old. This study provides evidence that daily increases in air pollution, especially PM2.5, result in a higher observed risk of hospitalization from COVID-19. Females and the elderly may be disproportionately affected.

Does urban greenness reduce loneliness and social isolation among Canadians? A cross-sectional study of middle-aged and older adults of the Canadian Longitudinal Study on Aging (CLSA).

OBJECTIVES: Urban greenness has been shown to confer many health benefits including reduced risks of chronic disease, depression, anxiety, and, in a limited number of studies, loneliness. In this first Canadian study on this topic, we investigated associations between residential surrounding greenness and loneliness and social isolation among older adults. METHODS: This cross-sectional analysis of the Canadian Longitudinal Study on Aging included 26,811 urban participants between 45 and 86 years of age. The Normalized Difference Vegetation Index (NDVI), a measure of greenness, was assigned to participants' residential addresses using a buffer distance of 500 m. We evaluated associations between the NDVI and (i) self-reported loneliness using the Center for Epidemiological Studies Depression Scale, (ii) whether participants reported "feeling lonely living in the local area", and (iii) social isolation. Logistic regression models were used to characterize associations between greenness and loneliness/social isolation while adjusting for individual socio-economic and health behaviours. RESULTS: Overall, 10.8% of participants perceived being lonely, while 6.5% reported "feeling lonely in their local area". Furthermore, 16.2% of participants were characterized as being socially isolated. In adjusted models, we observed no statistically significant difference (odds ratio (OR) = 0.99; 95% confidence interval (CI) 0.93-1.04) in self-reported loneliness in relation to an interquartile range (IQR) increase of NDVI (0.06). However, for the same change in greenness, there was a 15% (OR = 0.85; 95% CI 0.72-0.99) reduced risk for participants who strongly agreed with "feeling lonely living in the local area". For social isolation, for an IQR increase in the NDVI, we observed a 7% (OR = 0.93; 95% CI 0.88-0.97) reduction in prevalence. CONCLUSION: Our findings suggest that urban greenness plays a role in reducing loneliness and social isolation among Canadian urbanites.

RéSUMé: OBJECTIFS: Il est démontré que la verdure urbaine confère de nombreux avantages pour la santé; elle réduit notamment les risques de maladies chroniques, de dépression et d'anxiété et, selon un petit nombre d'études, le risque de solitude. Dans cette première étude canadienne sur le sujet, nous avons étudié les associations entre la verdure de l'environnement résidentiel et la solitude et l'isolement social chez les adultes d'âge mûr. MéTHODE: Cette analyse transversale de l'Étude longitudinale canadienne sur le vieillissement a inclus 26 811 participantes et participants urbains de 45 à 86 ans. L'indice de végétation par différence normalisée (IVDN), un indicateur de verdure, a été assigné à l'adresse domiciliaire dans une zone tampon de 500 m. Nous avons évalué les associations entre l'IVDN et i) la solitude autodéclarée selon l'échelle de dépression du Center for Epidemiological Studies, ii) le fait de déclarer « vivre de la solitude dans sa zone locale ¼ et iii) l'isolement social. Des modèles de régression logistique ont servi à caractériser les associations entre la verdure et la solitude/l'isolement social, et nous avons apporté des ajustements pour tenir compte du statut socioéconomique et des comportements de santé individuels. RéSULTATS: Globalement, 10,8 % des participantes et des participants se sentaient seuls, et 6,5 % disaient « vivre de la solitude dans leur zone locale ¼. De plus, 16,2 % des participantes et des participants ont été caractérisés comme étant socialement isolés. Dans nos modèles ajustés, nous n'avons observé aucun écart significatif (rapport de cotes (RC) = 0,99; IC de 95 % : 0,93­1,04) dans la solitude autodéclarée en lien avec une augmentation de l'écart interquartile (EI) de l'IVDN (0,06). Cependant, pour le même changement dans la verdure, la probabilité pour les participantes et les participants d'être tout à fait d'accord avec l'énoncé qu'ils « vivent de la solitude dans leur zone locale ¼ était réduite de 15 % (RC = 0,85, IC de 95 % : 0,72­0,99). Et pour chaque augmentation de l'EI de l'IVDN, nous avons observé une baisse de 7 % (RC = 0,93, IC de 95 % : 0,88­0,97) de la prévalence de l'isolement social. CONCLUSION: Nos constatations indiquent que la verdure urbaine joue un rôle dans la réduction de la solitude et de l'isolement social chez les citadins et citadines au Canada.

Associations between paediatric obesity, chemical mixtures and environmental factors, in a national cross-sectional study of Canadian children.

BACKGROUND: Whilst single chemical exposures are suspected to be obesogenic, the combined role of chemical mixtures in paediatric obesity is not well understood. OBJECTIVES: We aimed to evaluate the potential associations between chemical mixtures and obesity in a population-based sample of Canadian children. METHODS: We ascertained biomonitoring and health data for children aged 3-11 from the cross-sectional Canadian Health Measures Survey from 2007 to 2019. Several chemicals of interest were measured in blood or urine and paediatric obesity was defined based on measured anthropometrics. Using quantile-based G computational analysis, we quantified the effects of three chemical mixtures selected a priori. Models were adjusted for sociodemographic and environmental factors identified through a directed acyclic graph. Results are presented through adjusted relative risks (RR) with 95% confidence intervals (95% CI). RESULTS: We included 9147 children. Of these, 24.1% were overweight or obese. Exposure to the mixture of bisphenol A, acrylamide, glycidamide, metals, parabens and arsenic increased the risk of childhood overweight or obesity by 45% (95% CI 1.09, 1.93), obesity by 109% (95% CI 1.27, 3.42) and central obesity by 82% (95% CI 1.30, 2.56). CONCLUSIONS: Our findings support the role of early childhood chemical exposures in paediatric obesity and the potential combined effects of chemicals.

Does air pollution increase the effect of aeroallergens on hospitalization for asthma?

BACKGROUND: Clinical experiments demonstrate that the asthmatic response to an aeroallergen can be enhanced by prior exposure to an air pollutant. OBJECTIVE: We sought to compare the effects of ambient aeroallergens on hospitalization for asthma between high and low air pollution days in 11 large Canadian cities. METHODS: Daily time-series analysis was used, and results were adjusted for day of the week, temperature, barometric pressure, and relative humidity. RESULTS: The relative risk of admission for an interquartile increase in tree pollen levels was 1.124 (95% CI, 1.101-1.147) on days of lower values of fine particulate matter with a median aerodynamic diameter less than or equal to 2.5 µm (PM(2.5)) compared with 1.179 (95% CI, 1.149-1.21) on days of higher PM(2.5) values. Significant (P ≤ .05) differences in the relative risks of admission between lower versus higher values of particulate matter with a median aerodynamic diameter less than or equal to 10 µm in diameter were 1.149 (95% CI, 1.118-1.181) versus 1.210 (95% CI, 1.161-1.261) for ascomycetes, 1.112 (95% CI, 1.085-1.14) versus 1.302 (95% CI, 1.242-1.364) for basidiomycetes, 1.159 (95% CI, 1.125-1.195) versus 1.149 (95% CI, 1.129-1.169) for deuteromycetes, and 1.061 (95% CI, 1.016-1.107) versus 1.117 (95% CI, 1.092-1.143) for weeds. CONCLUSION: We identified an association between aeroallergens and hospitalizations for asthma, which was enhanced on days of higher air pollution. Minimizing exposure to air pollution might reduce allergic exacerbations of asthma.

Does ambient air pollution influence biochemical markers of liver injury? Findings of a cross-sectional population-based survey.

BACKGROUND: There is limited evidence supporting an adverse effect of ambient air pollution on the liver. OBJECTIVES: To test the association between exposure to residential air pollution and serum biochemical indicators of liver injury. METHODS: We used a nationally representative sample of 32,989 participants aged 3-79 years old who participated in the Canadian Health Measures Survey between 2007 and 2019. Cross-sectional associations were assessed by generalized linear mixed models incorporating survey-specific sampling weights. RESULTS: The joint effect of an interquartile range (IQR) increase in nitrogen dioxide (NO2), ozone (O3) and fine particulate matter (PM2.5) was positively and significantly associated with all measures of liver injury adjusting for age, sex, education, income, smoking, alcohol consumption, body mass index (BMI), total cholesterol, diabetes, hypertension, and physical activity. The ranking of effect sizes from largest to smallest percent increases were 8.72% (95% confidence interval [CI] 7.56, 9.88) for alanine aminotransferase (ALT), 5.54% (95%CI 3.31, 7.77) for gamma-glutamyl transferase (GGT), 4.81% (95%CI 3.87, 5.74) for aspartate aminotransferase (AST), 2.46% (95%CI 0.26, 4.65) for total bilirubin (TBIL) and 1.18% (95%CI 0.62, 1.75) for alkaline phosphatase (ALP). Findings were not significantly different when stratified by age (≤16, >16 yr), sex, smoking (current, other), cholesterol (≤6.18, >6.18 mmol/l) and BMI (<30, ≥30 kg/m2). DISCUSSION: These findings suggest that ambient air pollution may have a relatively small impact on the liver, but these changes may have significant impact from a population health perspective, considering the ubiquitous nature of air pollution, or for individuals exposed to very high levels of air pollution.

Personal exposure to specific volatile organic compounds and acute changes in lung function and heart rate variability among urban cyclists.

BACKGROUND: Few studies have examined the acute cardiorespiratory effects of specific volatile organic compound (VOC) exposures from traffic pollution. METHODS: A cross-over study was conducted among 42 healthy adults during summer 2010 in Ottawa, Canada. Participants cycled for 1-h along high and low-traffic routes and VOC exposures were determined along each route. Lung function, exhaled nitric oxide, and heart rate variability were monitored before cycling and 1-4h after the start of cycling. Bayesian hierarchical models were used to examine the relationship between 26 VOCs and acute changes in clinical outcomes adjusted for potential confounding factors. RESULTS: Each inter-quartile range (IQR) increase in propane/butane exposure was associated with a 2.0 millisecond (ms) (95% CI: 0.65, 3.2) increase in SDNN (standard deviation of normal-to-normal intervals), a 24 ms(2) (95% CI: 6.6, 41) increase in HF (high frequency power), and a 65 ms(2) (95% CI: 11, 118) increase in LF (low frequency power) in the hours following cycling. IQR increases in ethane and isoprene were associated with a 5.8 ms (95% CI: -9.8, -1.7): decrease in SDNN and a 24 ms(2) (95% CI: -44, -7.9) decrease in HF, respectively. IQR increases in benzene exposure were associated with a 1.7 ppb (95% CI: 1.1, 2.3) increase in exhaled nitric oxide and each IQR increase in 3-methylhexane exposure was associated with a 102 mL (95% CI: -157, -47) decrease in forced expiratory volume in 1-s. CONCLUSIONS: Exposure to traffic-related VOCs may contribute to acute changes in lung function, inflammation, or heart rate variability.

Demographics, sleep apnea and positive airway pressure (PAP) treatment-related characteristics associated with PAP adherence: A large retrospective community-based longitudinal observational study.

OBJECTIVE/BACKGROUND: Despite many years of research, multiple factors have inconsistently shown to be associated with positive airway pressure (PAP) adherence. We conducted a retrospective observational study to evaluate the association between selected demographics, obstructive sleep apnea (OSA) - and generally available PAP treatment-related factors with objective PAP therapy adherence. PATIENTS/METHODS: We considered all consented individuals with OSA who purchased a PAP device from a registered vendor (Ottawa, Ontario) between 2011 and 2017 who had usage data available (n = 11,614). PAP adherence was measured objectively as PAP use for at least 4 h on at least 70% of days on treatment. RESULTS: In our cohort, 7147 (61.5%) participants were deemed adherent to PAP over a median of 214 days (IQR: 84-675). The median percentage of days PAP therapy was used was 82% (IQR: 48-97%), and the median number of days PAP therapy was used for greater than 4 h was 95 (IQR: 28-372). In multivariable logistic regression considering all variables available, increased body mass index, older age, and lower minimum SaO2 at baseline sleep study were significantly associated with increased PAP adherence. Individuals who were using PAP longer and with greater adherence during the first month were subsequently more adherent to therapy. We also found a different predictive ability of PAP adherence-related factors by age and sex. CONCLUSIONS: In this retrospective community-based longitudinal observational study, we identified readily available demographics and OSA-related factors associated with PAP adherence. We also confirmed previous findings on age and sex disparities in adherence to PAP.