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.

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.

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.

The risk of dying on days of higher air pollution among the socially disadvantaged elderly.

RATIONALE: The estimated mortality rate associated with ambient air pollution based on general population studies may not be applicable to certain subgroups. OBJECTIVE: The objective of the present study was to determine the influence of age, education, employment status and income on the risk of mortality associated with ambient air pollution. METHODS: Daily time-series analyses tested the association between daily air pollution and daily mortality in seven Chilean urban centers during the period January 1997-December 2007. Results were adjusted for long-term trends, day-of-the week and humidex. RESULTS: Interquartile increases in particulate matter (PM(10) and PM(2.5)), sulphur dioxide, nitrogen dioxide, carbon monoxide, and elemental and organic carbon were associated with a 4-7% increase in mortality among those who did not complete primary school (p<0.05) vs. 0.5-1.5% among university graduates (p>0.05). Among those at least 85 years of age respective estimates were 2-7%. However, among the elderly who did not complete primary school, respective estimates were 11-19% (p<0.05). The degree of effect modification was less for income and employment status than education, and sex did not modify the results. CONCLUSION: The socially disadvantaged, especially if elderly appear to be especially susceptible to dying on days of higher air pollution. Concentrations deemed acceptable for the general population would not appear to protect this susceptible subgroup.

Respiratory Symptoms Are Associated With Frailty in Older Adults With Normal Spirometry, Independent of Smoking, in the Canadian Longitudinal Study of Aging.

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 ß 0.023, 95% CI 0.022-0.025) and current smokers with > 10 pack-year exposure (adjusted ß 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.

A comprehensive analysis of factors related to lung function in older adults: Cross-sectional findings from the Canadian Longitudinal Study on Aging.

Maintenance of lung function is an often underappreciated, yet critical component of healthy aging. Given the unprecedented shift in the average age of Canadians over the next half century, it will be important to investigate the determinants of lung function in the elderly. In the following study, we estimated the association between lung function and a broad array of factors related to sociodemographics, lifestyle, chronic medical conditions and psychosocial factors in older adults aged 45-86 years old using cross-sectional data from the Canadian Longitudinal Study of Aging (n = 21,338). In addition to examining the entire cohort, we also performed stratified analyses within men/women, adults aged 45-64/65+, and healthy/comorbid. In multivariable regression, our explanatory factors (excluding age, sex, height and ethnicity) were able to explain 17% and 11% of the total variance in FEV1 and FEV1/FVC, respectively. Notable and significant contributions were observed for respiratory disease, smoking, obesity, income, and physical activity, while psychosocial factors mainly exhibited non-significant associations. Generally, these associations were stronger for males than females, and adults 65 and older as compared to those aged 45-64. Our findings indicate that there are pervasive and generally under-recognized sociodemographic and lifestyle factors that exhibit significant associations with FEV1 and FEV1/FVC in older adults. While implication of causality in these relationships is not possible due to the cross-sectional nature of the study, future work aiming to investigate determinants of lung health in older adults may choose to target these factors, given that many are modifiable.

Air pollution and hospitalization for headache in Chile.

The authors performed a time-series analysis to test the association between air pollution and daily numbers of hospitalizations for headache in 7 Chilean urban centers during the period 2001-2005. Results were adjusted for day of the week and humidex. Three categories of headache-migraine, headache with cause specified, and headache not otherwise specified-were all associated with air pollution. Relative risks for migraine associated with interquartile-range increases in specific air pollutants were as follows: 1.11 (95% confidence interval (CI): 1.06, 1.17) for a 1.15-ppm increase in carbon monoxide; 1.11 (95% CI: 1.06, 1.17) for a 28.97-microg/m(3) increase in nitrogen dioxide; 1.10 (95% CI: 1.04, 1.17) for a 6.20-ppb increase in sulfur dioxide; 1.17 (95% CI: 1.08, 1.26) for a 69.51-ppb increase in ozone; 1.11 (95% CI: 1.00, 1.19) for a 21.51-microg/m(3) increase in particulate matter less than 2.5 mum in aerodynamic diameter (PM(2.5)); and 1.10 (95% CI: 1.04, 1.15) for a 37.79-microg/m(3) increase in particulate matter less than 10 mum in aerodynamic diameter (PM(10)). There was no significant effect modification by age, sex, or season. The authors conclude that air pollution appears to increase the risk of headache in Santiago Province. If the relation is causal, the morbidity associated with headache should be considered when estimating the burden of illness and costs associated with poor air quality.

Components of particulate air pollution and mortality in Chile.

To determine the association between several elements of fine particulate air pollution (PM2.5) and mortality in a general population sample, daily time-series analysis was used to test the association between daily mortality and components of PM2.5 measured in downtown Santiago, Chile between 1998 and 2006. The strongest individual effect was seen for elemental carbon. A 5.28 ug/m3 increase in elemental carbon was associated with a relative risk (RR) of 1.08 (95% CI = 1.07-1.09) for total non-accidental mortality. Using factor analysis, a group of elements consistent with a mobile combustion source (carbon monoxide, nitrogen dioxide, elemental and organic carbon) was significantly associated with total mortality (RR 1.11; 95% CI = 1.083-1.138). Soil-sourced particles had a weaker but statistically significant mortality effect. Of the many sources of particulate air pollution, those from motor vehicle exhaust had the greatest observed effect on mortality.

Is residential ambient air limonene associated with asthma? Findings from the Canadian Health Measures Survey.

Asthma is a common chronic disease. Exposure to limonene is commonplace because it may be used in the manufacture of personal care products and household cleaners. We investigated the influence of limonene on asthma in a population-based sample of approximately 3000 Canadians. During the Canada Health Measures Survey, carried out between 2012 and 2013, participants were asked if they wheezed or had a diagnosis of asthma, and underwent spirometry and measurement of the fraction of exhaled nitric oxide (FeNO). These variables were tested for an association with limonene concentrations measured in their household air samples, using linear regression analysis A 100% increase in air limonene concentration was associated with an approximate 17% adjusted relative increase wheezing with an odds ratio of 1.17 (95%CI 1.16, 1.18). The percent change in FeNO for a 100% increase in limonene was twice as large for children, 2.89% (95% CI 1.88, 4.43) compared to adults, 1.44% (95%CI 1.16, 1.79). Among boys, the odds ratio was 1.50 (95%CI 1.48, 1.52) between a 100% increase in limonene and a diagnosis of asthma. This study provides evidence that household exposure to limonene may increase the prevalence of asthma in the general population.

Tree pollen and hospitalization for asthma in urban Canada.

BACKGROUND: Allergy to tree pollen is common and aeroallergens have been associated with severe asthma exacerbations in the community setting. To determine the impact of different trees on asthma, we tested the association between daily hospitalizations for asthma and daily concentrations of different tree pollens in 10 large Canadian cities. METHODS: Daily time-series analyses were employed to remove unwanted temporal trends. For each family or genus, results were adjusted for day of the week, temperature, barometric pressure and relative humidity. Results were expressed as the percentage increase in asthma hospitalizations related to an increase in tree pollen concentration equivalent in magnitude to its interquartile range. RESULTS: For an interquartile increase in daily tree pollen concentration, percent increases in daily hospitalization for asthma were: 2.63% (95% CI 1.19-4.07) for Ulmus (elm), 2.45% (1.12-3.78) for the group containing Pinaceae (pine, fir, spruce), Tsuga (hemlock) and Larix (larch, tamarack); 2.32% (0.93-3.71) for the group containing Quercus (oak) and Castanea (chestnut), and 2.16% (0.70-3.62) for Acer (boxelder and maple). Statistically significant (p < 0.05) but small (<2%) effects were observed for Fraxinus (ash), Populus (aspen, poplar), Alnus (alder), Betula (birch) and Corylus (hazelnut). CONCLUSIONS: Several common tree pollens are an important cause of acute exacerbations of asthma severe enough to require hospitalization.

Overdiagnosis of asthma in obese and nonobese adults.

BACKGROUND: It is unclear whether asthma is overdiagnosed in developed countries, particularly among obese individuals, who may be more likely than nonobese people to experience dyspnea. METHODS: We conducted a longitudinal study involving nonobese (body mass index 20-25) and obese (body mass index >/= 30) individuals with asthma that had been diagnosed by a physician. Participants were recruited from 8 Canadian cities by means of random-digit dialing. A diagnosis of current asthma was excluded in those who did not have evidence of acute worsening of asthma symptoms, reversible airflow obstruction or bronchial hyperresponsiveness, despite being weaned off asthma medications. We stopped asthma medications in those in whom a diagnosis of asthma was excluded and assessed their clinical outcomes over 6 months. RESULTS: Of 540 individuals with physician-diagnosed asthma who participated in the study, 496 (242 obese and 254 nonobese) could be conclusively assessed for a diagnosis of asthma. Asthma was ultimately excluded in 31.8% (95% confidence interval [CI] 26.3%-37.9%) in the obese group and in 28.7% (95% CI 23.5%-34.6%) in the nonobese group. Overdiagnosis of asthma was no more likely to occur among obese individuals than among nonobese individuals (p = 0.46). Of those in whom asthma was excluded, 65.5% did not need to take asthma medication or seek health care services because of asthma symptoms during a 6-month follow-up period. INTERPRETATION: About one-third of obese and nonobese individuals with physician-diagnosed asthma did not have asthma when objectively assessed. This finding suggests that, in developed countries such as Canada, asthma is overdiagnosed.

Cardiorespiratory Effects of Air Pollution in a Panel Study of Winter Outdoor Physical Activity in Older Adults.

OBJECTIVE: The aim of this study was to assess cardiorespiratory effects of air pollution in older adults exercising outdoors in winter. METHODS: Adults 55 years of age and older completed daily measurements of blood pressure, peak expiratory flow and oximetry, and weekly measurements of heart rate variability, endothelial function, spirometry, fraction of exhaled nitric oxide and urinary oxidative stress markers, before and after outdoor exercise, for 10 weeks. Data were analyzed using linear mixed effect models. RESULTS: Pooled estimates combining 2014 (n = 36 participants) and 2015 (n = 34) indicated that an interquartile increase in the Air Quality Health Index was associated with a significant (P < 0.05) increase in heart rate (0.33%) and significant decreases in forced expiratory volume (0.30%), and systolic (0.28%) and diastolic blood pressure (0.39%). CONCLUSION: Acute subclinical effects of air pollution were observed in older adults exercising outdoors in winter.

Air pollution and mortality in Chile: susceptibility among the elderly.

OBJECTIVE: The estimated mortality rate associated with ambient air pollution based on general population studies may not be representative of the effects on certain subgroups. The objective of the present study was to determine the influence of relatively high concentrations of air pollution on mortality in a general population sample and in the very elderly. STUDY DESIGN: Daily time-series analyses tested the association between daily air pollution and daily mortality in seven Chilean urban centers during 1997-2003. Results were adjusted for day of the week and humidex. RESULTS: Daily averaged particulate matter with aerodynamic matter < 10 microm (PM(10)) was 84.88 microg/m(3), sulfur dioxide was 14.08 ppb, and carbon monoxide was 1.29 ppb. The 1-hr maximum ozone was 100.13 ppb. The percentage increases in nonaccidental mortality associated with an increase in PM(10) equivalent to its mean were 4.53 (t-ratio 1.52) for those < 65 years and 14.03 (3.87) for those > 85 years. Respective values were 4.96 (1.17) and 8.56 (2.02) for O(3); 4.77 (2.50) and 7.92 (3.23) for SO(2); and 4.10 (2.52) and 8.58 (4.45) for CO. CONCLUSION: Our results suggest that the very elderly are particularly susceptible to dying from air pollution. Concentrations deemed acceptable for the general population may not adequately protect the very elderly.

Indoor air quality and the risk of lower respiratory tract infections in young Canadian Inuit children.

BACKGROUND: Inuit infants have the highest reported rate of hospital admissions because of lower respiratory tract infections in the world. We evaluated the prevalence of reduced ventilation in houses in Nunavut, Canada, and whether this was associated with an increased risk of these infections among young Inuit children. METHODS: We measured ventilation in 49 homes of Inuit children less than 5 years of age in Qikiqtaaluk (Baffin) Region, Nunavut. We identified the occurrence of lower respiratory tract infections using a standardized questionnaire. Associations between ventilation measures and lower respiratory tract infection were evaluated using multiple logistic regression models. RESULTS: The mean number of occupants per house was 6.1 people. The mean ventilation rate per person was 5.6 L/s (standard deviation [SD] 3.7); 80% (37/46) of the houses had ventilation rates below the recommended rate of 7.5 L/s per person. The mean indoor carbon dioxide (CO2) concentration of 1358 (SD 531) ppm was higher than the recommended target level of 1000 ppm. Smokers were present in 46 homes (94%). Of the 49 children, 27 (55%) had a reported history of lower respiratory tract infection. Reported respiratory infection was significantly associated with mean CO2 levels (odds ratio [OR] 2.85 per 500-ppm increase in mean indoor CO2, 95% confidence interval [CI] 1.23-6.59) and occupancy (OR 1.81 for each additional occupant, 95% CI 1.14-2.86). INTERPRETATION: Reduced ventilation and crowding may contribute to the observed excess of lower respiratory tract infection among young Inuit children. The benefits of measures to reduce indoor smoking and occupancy rates and to increase ventilation should be studied.

The influence of polycyclic aromatic hydrocarbons on lung function in a representative sample of the Canadian population.

We investigated the associations between exposure to polycyclic aromatic hydrocarbons (PAHs) and selected respiratory physiologic measures in cycles 2 and 3 of the Canadian Health Measures Survey, a nationally representative population sample. Using generalized linear mixed models, we tested the association between selected PAH metabolites and 1-second forced expiratory volume (FEV1), forced vital capacity (FVC), and the ratio between the two (FEV1/FVC) in 3531 people from 6 to 79 years of age. An interquartile change in urinary PAH metabolite was associated with significant decrements in FEV1 and FVC for eight PAHs, 2-hydroxynapthalene, 1-, and 2-hydroxyphenanthrene, 2-, 3-, and 9-hydroxyfluorene and 3- and 4-hydroxyphenanthrene. Exposure to PAH may negatively affect lung function in the Canadian population.

Cardio-Respiratory Effects of Air Pollution in a Panel Study of Outdoor Physical Activity and Health in Rural Older Adults.

OBJECTIVE: To examine cardio-respiratory effects of air pollution in rural older adults exercising outdoors. METHODS: Adults 55 and over completed measurements of blood pressure, peak expiratory flow and oximetry daily, and of heart rate variability, endothelial function, spirometry, fraction of exhaled nitric oxide and urinary oxidative stress markers weekly, before and after outdoor exercise, for 10 weeks. Data were analyzed using linear mixed effect models. RESULTS: Pooled estimates combining 2013 (n = 36 participants) and 2014 (n = 41) indicated that an interquartile increase in the air quality health index (AQHI) was associated with a significant (P < 0.05) increase in heart rate (2.1%) and significant decreases in high frequency power (-19.1%), root mean square of successive differences (-9.5%), and reactive hyperemia index (-6.5%). CONCLUSIONS: We observed acute subclinical adverse effects of air pollution in rural older adults exercising outdoors.

Gaseous air pollutants and hospitalization for respiratory disease in the neonatal period.

OBJECTIVE: Current levels of ambient air pollution are associated with morbidity and mortality in the general population. To determine the influence of gaseous air pollutants on neonatal respiratory morbidity, we tested the association between daily respiratory hospitalizations and daily concentrations of ambient air pollution gases: ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide, in 11 large Canadian cities. STUDY DESIGN: Daily time-series analyses were employed and results were adjusted for day of the week, temperature, barometric pressure, and relative humidity. RESULTS: The percent increases in hospitalization associated with an increase in air pollution equivalent to its interquartile range were 3.35 [95% confidence interval (CI), 1.73-4.77] for O3, 2.85 (95% CI, 1.68-4.02) for NO2, 1.66 (95% CI, 0.63-2.69) for SO2, and 1.75 (95% CI, 0.48-3.02) for CO. The independent effect of all pollutants combined was 9.61% (95% CI, 4.52-14.7%). CONCLUSION: Our results suggest that neonates are experiencing adverse effects of air pollution at current levels in Canada, and that accounts for a significant proportion of hospitalizations in this subgroup.

The prevalence of airflow obstruction in rural primary care.

UNLABELLED: Spirometry has been reported to be under-utilized, and airflow obstruction may be under-diagnosed, in primary care practice. STUDY OBJECTIVES: The objective of this study was to determine the prevalence and severity of airflow obstruction in rural primary care settings and the degree to which it can be predicted by clinical characteristics. Spirometry was performed in patients 35 years and older who had smoked, presenting for any reason to one of eight rural primary care practices. Obstruction was defined as an FEV(1)/FVC<0.70. A total of 1046 subjects were recruited of whom 1034 had acceptable and reproducible spirometry. Airflow obstruction was detected in 17.4% (180 patients). Of those with obstruction, 77.2% (se 3.1%) had at least one respiratory symptom versus 62.4% (se 1.6%) without obstruction (P=0.0002). Only 44.9% (se 3.7%) of those with airflow obstruction had been previously diagnosed with obstructive lung disease. Of those with an FEV(1)<50% of predicted, 85% (se 5.6%) were breathless on exertion; however, only 63% (se 7.6%) were being treated with respiratory medications. We conclude that airflow obstruction is common in rural primary care practice and cannot be accurately predicted by symptoms. It is undiagnosed half of the time, and often not treated even when symptomatic.

Do gender, education, and income modify the effect of air pollution gases on cardiac disease?

OBJECTIVE: We sought to determine whether gender, education, and income influence the susceptibility to ambient air pollution. METHODS: We determined the association between daily cardiac hospitalizations and daily concentrations of gaseous air pollutants in 10 large Canadian cities using time-series analyses adjusted for day-of-the week, temperature, barometric pressure, relative humidity. RESULTS: Percentage increases in hospitalization associated with an increase in air pollution equivalent to its mean value were statistically significant for ozone, carbon monoxide and nitrogen dioxide individually (P < 0.05) and the combined pollutant effect was 8.5% (95% confidence interval: 1.8, 14.6). The air pollution-cardiac disease association was not significantly influenced by gender or community level of education or income. CONCLUSION: Short-term changes in air pollution may adversely affect cardiac disease but gender, and community education and income do not accurately identify those with increased susceptibility.

Does Mental Health Status Influence Susceptibility to the Physiologic Effects of Air Pollution? A Population Based Study of Canadian Children.

BACKGROUND: Both air pollution exposure and the presence of mental illness are associated with an increased risk of physical illness. OBJECTIVE: To determine whether or not children with less favourable mental health are more susceptible to pulmonary and cardiovascular effects of ambient air pollution, compared to those who are mentally healthy. METHODS: We carried out a cross-sectional study of 1,883 children between the ages of 6 and 17 years of age who participated in the Canadian Health Measures population survey between 2007 and 2009. Subjects were assigned the air pollution values obtained from the National Air Pollution monitor closest to their neighborhood. Lung function, heart rate and blood pressure were stratified by indicators of mental health. The latter were ascertained by questions about feelings of happiness, a diagnosed mood disorder, and the emotional symptom subscale of the Strengths and Difficulties Questionnaire. RESULTS: Among those who reported a mood disorder, an interquartile increase in ozone was associated with increases in systolic and diastolic pressures of 3.8 mmHg (95% CI 1.6, 5.9) and 3.0mmHg (95%CI 0.9, 5.2) respectively, and a decreases in FVC of 7.6% (95% CI 2.9, 12.3). No significant changes in these variables were observed in those who did not report a mood disorder. Among those with unfavourable emotional symptoms, ozone was associated with a 6.4% (95% CI 1.7, 11.3) increase in heart rate, a 4.1% (95%CI 1.2, 7.1) increase in systolic blood pressure, and a 6.0% (95% CI 1.4, 10.6) decrease in FEVl. No significant effect was seen in these variables among those with no emotional symptoms. CONCLUSIONS: In the Canadian population, children who report mood disorders or unfavourable emotional symptoms appear to be more vulnerable to the adverse physiologic effects of air pollution.