BACKGROUND:Ambient air pollution has been linked to biomarkers of liver injury. Little information exists on these effects at relatively low air pollution levels and among children. The relative hepatic toxicity of air pollution mixes from specific emission sectors has not been previously investigated. OBJECTIVES:To test associations between sector-specific air pollution (SSAP) and biomarkers of liver injury. METHODS:Using generalized linear mixed models, we tested associations between SSAP exposure and liver injury biomarkers in 30,781 participants aged 3-79 years, in the nationally representative Canadian Health Measures Survey (2007 and 2019) who were exposed to relatively low air pollution concentrations. RESULTS:Interquartile range (IQR) increases in SSAP from residential (RES), on- and off-road transportation (ONRD, OFRD), air-marine-rail (AMR), upstream and downstream oil and gas production (UPOG, DNOG), chemical manufacturing (MAN) and pulp and paper (P&P) sectors were associated with significant increases in bilirubin (BIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). The largest effects were for alkaline phosphatase with increases of 1.86% (95% CI 0.46,3.26), and 1.58% (95% 0.08, 3.07) for AMR, and DNOG-attributable concentrations, respectively. Among children <13 years, BIL, AST and gamma-glutamyl transferase were positively and significantly associated with all sources, with the largest effect being a 0.8% increase in BIL per IQR increase in UPOG. CONCLUSION:The relatively low levels of SSAP in Canada were associated with significant increases in liver injury biomarkers, including among children. These observed effects may be consequential given the widespread population exposure especially in countries with higher levels of air pollution.

Importance:There is limited research examining the association between wildfire smoke, an increasingly frequent exposure, and headache-related emergency department (ED) visits, despite headaches being a leading cause of years lived with disability globally. Objective:To examine the association between wildfire-sourced fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) and ED visit for migraine and other primary headache syndromes (MOPHS) compared with nonwildfire-sourced PM2.5, and to assess the variation across sociodemographic factors. Design, Setting, and Participants:This case-crossover study used conditional logistic regression to examine ED visits during wildfire seasons (May 1 to October 31) from 2010 to 2023 in Alberta and Ontario provinces in Canada. Case days were matched to referent days by day of week, month, year, and forward sortation area (first 3 postal code characters). Seven-day cumulative lags were evaluated. All ED visits recorded in the National Ambulatory Care Reporting System with a primary diagnosis of MOPHS were included. Statistical analyses were conducted from April to December 2025. Exposure:Total PM2.5 concentrations and wildfire day (WFD). Daily mean wildfire-sourced PM2.5 was estimated using the Canadian Optimized Statistical Smoke Exposure Model. WFDs were defined by smoke plume presence and total PM2.5 concentration exceeding a predefined threshold based on the mean plus 1.5 SD of PM2.5 on days without a smoke plume. Wildfire-sourced PM2.5 was defined as the difference between total PM2.5 concentration on a WFD and expected background PM2.5 concentration on non-WFDs. Main Outcomes and Measures:ED visits for migraine (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Canada code G43) and other primary headache syndromes (code G44). Results:Among the 997 701 ED visits for 622 753 patients (mean [SD] age, 24.6 [16.8] years; 760 795 females [76.3%]) for MOPHS identified during the study period, 86.2% of visits were for migraines and 13.8% were for other primary headache syndromes. Wildfire-sourced PM2.5 was associated with a 6.07% (95% CI, 5.75%-6.39%) increase in ED visits. Associations appeared attenuated in the least materially and socially deprived quantile (for both provinces combined, the percentage increase in MOPHS was smallest for the Material and Social Deprivation Index quintile 1: 3.61% [95% CI, 1.93%-5.63%] and largest for quintile 5: 10.42% [95% CI, 7.41%-13.49%]). In contrast, total PM2.5 concentration on non-WFDs was not significantly associated with ED visits (0.21%; 95% CI, -0.20% to 0.62%). Conclusions and Relevance:In this case-crossover study of ED visits in Alberta and Ontario, acute exposure to wildfire-sourced PM2.5 was associated with increased ED visit for MOPHS; associations were greater in magnitude for wildfire-sourced PM2.5 than nonwildfire-sourced PM2.5. These findings support the need for further research into wildfire smoke and severe headache-related outcomes.

Existing evidence on air pollution exposure and cardiometabolic biomarker associations does not consider pollution mixtures and sector-specific pollution contributions. Participants from the cross-sectional Canadian Health Measures Survey (2007-2019) were included. Annual average concentrations of ambient PM2.5, SO2, NO2, and O3 (2006-2019) were modeled using the Global Environmental Multi-scale - Modelling Air quality and Chemistry (GEM-MACH) chemical transport model at a 10 km by 10 km surface resolution from all sources combined as well as from eight specific sectors. The quantile g-computation model was used to estimate changes in lipid and glucose metabolic markers associated with interquartile increases in air pollution. A total of 30,781 participants aged 3-79 years were included in the study. Exposure to PM2.5, O3, NO2, and SO2 from all sectors was associated with increases in the ratio of total cholesterol to HDL (0.039, 95 % CI: 0.017,0.060), apolipoprotein B (0.011, 95 % CI: 0.006,0.017), fasting glucose (0.076, 95 % CI: 0.010,0.142), and insulin (3.159, 95 % CI: 1.180,5.138), as well as decreases in the cardioprotective lipids, HDL (-0.015, 95 % CI: 0.023,-0.008) and apolipoprotein A1 (-0.010, 95 % CI: 0.020,-0.000). Lipid and apolipoprotein levels as well as markers of insulin resistance were predominantly altered in children and younger adults, although there was no significant effect modification by age. On- and off-road transportation sectors were most frequently associated with adverse lipid biomarker effects. The joint effects of mean annual PM2.5, O3, NO2, and SO2 exposures were associated with worsening cardiometabolic markers. Further research is required to better understand the mechanisms by which specific air pollution components disrupt metabolic pathways.

Airborne algae have been associated with respiratory illness in the setting of coastal harmful algae blooms but little is known about their effects in urban populations distributed across a country, and whether ambient air pollution is an effect modifier. Using cross-sectional data from 11,256 participants of the Canadian Health Measures Survey (CHMS), we tested the association between lung function expressed as a forced expiratory volume (FEV1) and airborne concentrations of algae measured by a rotation impact sampler in the participant's city of residence on the day of spirometric testing. The daily upper 95th percentiles of algae ranged from 12.7 to 104.3 grains/m3. An interquartile range increase in algae was associated with a 2.55% (95%CI: 1.88, 3.23) decrease in percent predicted 1-s forced expiratory volume pp FEV1, and a 2.54% (95%CI: -2.93, -2.14) decrease in pp FEV1/forced vital capacity (FVC) after adjustment for participants' age, sex, education, annual income, active cigarette smoking, environmental tobacco smoke exposure, fine particulate air pollution (PM2.5), total fungal spores and total pollen grains. An interquartile increase in PM2.5 was associated with a 0.86% (95%CI: 0.78, 0.94) decrease in FEV1, but we found no significant interaction between air pollutants and algae. Our findings suggest that independent of air pollution, airborne algae may influence lung function in urban populations widely distributed across Canada, and the observed effect was of larger magnitude than that of air pollution.

AbstractWe examined the association between walkability and blood lipids in a nationally representative sample of 29,649 participants aged 3–79 years who participated in the Canadian Health Measures Survey (CHMS) cycles 1 to 6. We focused on seven lipid biomarkers: apolipoprotein A (Apo A), apolipoprotein B (Apo B), triglycerides (TG), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), total cholesterol (TC), and TC/HDL. Cross-sectional associations were analyzed using generalized linear mixed models incorporating survey-specific sampling weights. An increase in the Canadian Active Living Environments Index, a measure of neighborhood walkability, equivalent to the magnitude of its interquartile range (IQR) was associated with the following percentage (95% confidence intervals (CI)) changes in lipids: decreased TG, -2.85 (-4.77, -0.93) and TC/HDL, -1.68 (-2.80, -0.56), and increased HDL, 1.68 (0.93, 2.42). Significant effects were largely restricted to adults (aged 17 to 79). In the younger age group there were no significant associations between walkability and lipids in the fully adjusted model. Significant associations were more frequently seen in females than males. For females, fully adjusted significant inverse associations were observed for TG, LDL, and TC/HDL, and there were positive associations with HDL and Apo A. Canadians living in more walkable neighborhoods have more favorable lipid profiles, suggesting that the built environment has the potential to influence the risk profile for cardiovascular health, especially among adults and females.

SummaryWe 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.

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-beta, 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.

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.

Abstract 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.

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.

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.

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.

Per- and poly-fluoroalkyl substances (PFAS) are ubiquitous and may persist in human tissue for several years. Only a small proportion of PFAS have been studied for human health effects. We tested the association between human blood levels of six PFAS and several clinical measures of organ and metabolic function in a nationally representative sample of 6768 participants aged 3-79 years old who participated in the Canadian Health Measures Survey. Cross-sectional associations were assessed by generalized linear mixed models incorporating survey-specific sampling weights. An increase in perfluorooctanoic acid (PFOA) equivalent to the magnitude of its geometric mean (GM) of 2.0 μg/L was associated with percentage (95% CI) increases in serum enzymes reflecting liver function: aspartate aminotransferase (AST) 3.7 (1.1, 6.4), gamma-glutamyl transferase (GGT) 11.8 (2.5, 21.8), alanine aminotransferase (ALT) 3.2 (0.5, 5.9), and bilirubin 3.6 (2.7, 4.5). A GM increase in perfluorodecanoic acid (PFDA) of 0.2 μg/L was positively associated with percentage increases in GGT, triglycerides, low-density lipoprotein (LDL) cholesterol, total cholesterol, and calcium with respective increases of 15.5 (2.2, 30.4), 7.0 (1.0, 13.2), 10.7 (5.5, 16.1), 2.8 (0.2, 5.3), and 0.8 (0.3, 1.3). PFOA, perfluorooctane sulfonate (PFOS), PFDA and perfluorononanoic acid (PFNA) were positively associated with GGT. All six congeners were positively associated with at least one biomarker of lipid metabolism, and 5 of 6, PFOA, PFOS, PFDA, perfluorohexane sulfonate (PFHxS) and PFNA were positively associated with serum calcium. Exposure to selected PFAS is associated with clinical blood tests reflecting metabolism and the function of several organ systems. These relatively small changes may possibly indicate early pathology that is clinically inapparent and may possibly be of significance in a general population or in individuals exposed to very high levels of PFAS.

BACKGROUND: Ambient air pollution may affect the severity of untreated OSA, but it is unknown whether air pollution adversely impacts the effectiveness of positive airway pressure (PAP) therapy. RESEARCH QUESTION: Do short-term changes in outdoor air pollution adversely impact adults with OSA using PAP therapy? STUDY DESIGN AND METHODS: We conducted a retrospective community-based repeated-measures longitudinal study of adults with OSA who purchased a PAP device from a registered equipment provider between 2013 and 2017 (Ontario, Canada) and had data on the daily device-derived residual apnea-hypopnea index (AHI(Flow)). We linked daily PAP-derived data to air pollution databases using postal codes. The primary exposures were mean nocturnal (8 pm to 8 am) residential concentrations of ozone, fine particulate matter, nitrogen dioxide, carbon monoxide, sulfur dioxide, and the Air Quality Health Index (AQHI). Potential confounders considered were demographics, season and year of exposure, initial OSA severity, other PAP parameters, and climate-related variables. RESULTS: Eight thousand one hundred forty-eight adults were analyzed with a median of 89 days (interquartile range [IQR], 29-302 days) of observation during which PAP was used for >= 4 h. The median daily AHI(Flow) was 1.2/h (IQR, 0.5-2.5/h). In mixed multivariate regression analyses, an increase in air pollution was associated with a statistically significant increase in AHI(Flow) for most statistical models. The largest effect was for the AQHI: an increase in AHI(Flow) while comparing highest vs lowest quartiles was 0.07/h (95% CI, 0.05-0.10/h). INTERPRETATION: We demonstrated a modest but statistically significant increase in residual respiratory events during PAP therapy associated with an increase in air pollution concentrations.

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.

BACKGROUND AND AIM: Pediatric obesity rates in Canada have nearly tripled in the last 30 years, leading to increased rates of morbidity. While environmental exposures are suspected to be obesogenic, data are lacking and mostly employ a single-exposure approach. We aimed to evaluate the potential associations between multiple environmental factors and pediatric obesity. METHODS: We used nationally-representative biomonitoring and health data for children aged 3-11 from the cross-sectional Canadian Health Measures Survey. Chemicals of interest, monitored in blood or urine, were polyaromatic hydrocarbons (PAH), bisphenol A (BPA), parabens, perfluorinated compounds, phthalates and metals. Obesity was characterized by WHO sex-specific body mass index (BMI) for age z-scores. Central obesity was defined using international waist circumference percentile cutoffs. Using generalized additive models, we examined the impact of multiple environmental characteristics, including proximity to greenspace, fine particulate matter (PM 2.5), nighttime light brightness and walkability (active living environment), on associations between single-chemical exposures and obesity. Using quantile-based G computational analysis, we quantified the combined effects of chemicals captured in all cycles, where feasible. Models were adjusted for confounders identified in a directed acyclic graph. Results are adjusted odd ratios with 95% confidence intervals (95% CI). RESULTS: Overall, 9,147 children were included. In single-exposure models, several PAH compounds, BPA, cadmium and total phthalates were linked to increased obesity and central obesity. Per interquartile range increase in total PAHs, risks of obesity and central obesity were elevated to 1.09 (95%CI 1.01, 1.18) and 1.14 (95%CI 1.01, 1.30), respectively. In combined-effects models for PAHs and BPA, risks of obesity and central obesity were strengthened to 1.46 (95%CI 1.20, 1.78) and 1.29 (95%CI 1.10, 1.56), respectively. CONCLUSIONS: Our findings support the role of early chemical exposure in pediatric obesity, particularly PAHs. The combined effects of chemicals strengthened the observed associations. KEYWORDS: Pediatric; Chemicals; Obesity; Public Health; Environment

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.

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.

BACKGROUND: Recent studies have demonstrated that even in the absence of lung impairment as determined by spirometry, smoking and respiratory symptoms are associated with poor overall health and well-being. However, this relationship is not well defined; and it remains unclear the degree to which symptoms are related to poor health, independent of smoking. This is of particular importance to older adults, as they are more likely to exhibit respiratory symptoms and are, therefore, at risk of not receiving appropriate treatment if they have never smoked and have normal spirometry. METHODS: We performed a cross-sectional analysis of data from the Canadian Longitudinal Study on Aging to delineate the associations of respiratory symptoms and smoking on the health of participants age 45-86 who exhibited normal spirometry. Participant health was estimated using a frailty index, a multidimensional measure of vulnerability to adverse outcomes that has been validated in numerous health settings. RESULTS: Of the 21,293 participants included in our analysis, 87% exhibited a normal FEV1, FVC, and FEV1/FVC; of those, 45% reported at least one respiratory symptom, and 50% were former or current smokers. Both respiratory symptoms and smoking were independently associated with frailty (median interquartile range [IQR] = 0.11 [0.07-0.15]), the most substantial associations observed for those having at least one respiratory symptom (adjusted beta 0.023, 95% CI 0.022-0.025) and current smokers with > 10 pack-year exposure (adjusted beta 0.014, 95% CI [0.010-0.019). Not only was the association between symptoms and frailty evident in never smokers, a significant proportion of the total effect of smoking on frailty was observed to be mediated by symptoms. CONCLUSIONS: Our data show that respiratory symptoms, regardless of smoking history, were a significant correlate of frailty in older adults with normal spirometry. Hence, they should not be simply regarded as a benign by-product of aging.

BACKGROUND AND AIM: In Canada, an estimated 6.7 million people suffer from mental health disorders in any given year. An increasing number of recent studies have suggested links between greenspaces and improved health. Few Canadian studies, however, have examined greenness-mental health relationships. METHODS: We used cross-sectional data from the Canadian Longitudinal Study on Aging (CLSA) to characterize associations between greenness and prevalent mental health outcomes. Our analyses are based on 26,765 adults, 45 to 85 years of age, who lived in urban areas. The Normalized Difference Vegetation Index was used as a residential measure of greenness and we modelled exposures based on a series of buffer intervals (250m, 500m, 1000m). Four self-reported measures of mental health were assessed, and these included: i) the Center for Epidemiologic Studies Depression Scale (CES-D-10; short scale), ii) Perceptions of Mental health on the Likert scale, iii) Perceptions of General health on the Likert scale iv), and the Satisfaction With Life Scale (SWLS). We used multivariable logistic regression models to characterize associations between greenness and mental health. The resulting odds ratios, and their 95% confidence intervals, were adjusted for several important risk factors. RESULTS:Overall, 5.6% of the participants reported fair/poor mental health, 9.3% fair/poor general health, 12.2% were dissatisfied on the SWLS, and 15.9% reported moderate/serious depression. Greenness at 500m around the residential postal code was inversely associated with all four measures of mental health. Specifically, interquartile range increases in greenness significantly reduced the odds of moderate/serious depression by 12% [OR=0.88, (95% CI=0.83-0.93)], the odds of dissatisfaction by 13% [OR=0.87, (95% CI=0.81-0.92)], the odds of fair/poor mental health by 19% [OR=0.81, (95% CI=0.74-0.88)], and the odds of fair/poor general health by 10% [OR = 0.90, (95% CI =0.83-0.98)]. CONCLUSIONS:Our findings suggest that urban greenness confers mental health benefits, and provide some support for local initiatives to green neighbourhoods as a means to improve population health. KEYWORDS: Mental health, Depression, Adults, Greenness, CLSA