To determine the influence of endotoxin on the incidence of acute respiratory illness during the first 2 years of life, we carried out a longitudinal follow-up study, beginning at birth, of 332 children born in Prince Edward Island, Canada. We measured 5-day averaged air endotoxin in the homes of children, whose parents provided information by daily symptom diaries and twice-monthly telephone contact for up to 2 years. Endotoxin concentration was 0.49 +/- 3.49 EU/m3 (geometric mean +/- geometric SD), and number of annualized illness episodes was 6.83 +/- 2.80 (mean +/- SD). A doubling of the air endotoxin concentration was associated with an increase of 0.32 illness episodes per year (p = 0.0003), adjusted for age, year of study, breast-feeding, environmental tobacco smoke, child care attendance, indoor temperature, and income. Indoor mold surface area and fungal ergosterol were not significantly associated with endotoxin. Airborne endotoxin appears to be a risk factor for clinically symptomatic respiratory illnesses during the first 2 years of life independent of indoor fungus.
Social status influences asthma morbidity but the mechanisms are not well understood. To determine if sociodemographics influence the susceptibility to ambient aeroallergens, we determined the association between daily hospitalizations for asthma and daily concentrations of ambient pollens and molds in 10 large Canadian cities.
Daily time-series analyses were performed and results were adjusted for day of the week, temperature, barometric pressure, relative humidity, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Results were then stratified by age, gender, and neighborhood family education and income.
There appeared to be age and gender interactions in the relation between aeroallergens and asthma. An increase in basidiomycetes equivalent to its mean value, about 300/m3, increased asthma admissions for younger males (under 13 years of age) by 9.3% (95% CI, 4.8%, 13.8%) vs. 4.2% (95% CI, - 0.1%, 8.5%) for older males. The reverse was true among females with increased effect in the older age group: 2.3% (95% CI, 1.2%, 5.8%) in those under 13 years vs. 7.1% (95% CI, 4.1%, 10.1%) for older females. Associations were seen between aeroallergens and asthma hospitalization in the lowest but not the highest education group.
Our results suggest that younger males and those within less educated families may be more vulnerable to aeroallergens as reflected by hospitalization for asthma.
We sought to determine whether gender, education, and income influence the susceptibility to ambient air pollution.
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.
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
Few assessments of the costs and benefits of reducing acute cardiorespiratory morbidity related to air pollution have employed a comprehensive, explicit approach to capturing the full societal value of reduced morbidity.
We used empirical data on the duration and severity of episodes of cardiorespiratory disease as inputs to complementary models of cost of treatment, lost productivity, and willingness to pay to avoid acute cardiorespiratory morbidity outcomes linked to air pollution in epidemiological studies. A Monte Carlo estimation procedure was utilized to propagate uncertainty in key inputs and model parameters.
Valuation estimates ranged from 13 dollars (1997, Canadian) (95% confidence interval, 0-28 dollars) for avoidance of an acute respiratory symptom day to 5,200 dollars (4,000 dollars-6,400 dollars) for avoidance of a cardiac hospital admission. Cost of treatment accounted for the majority of the overall value of cardiac and respiratory hospital admissions as well as cardiac emergency department visits, while lost productivity generally represented a small proportion of overall value. Valuation estimates for days of restricted activity, asthma symptoms and acute respiratory symptoms were sensitive to alternative assumptions about level of activity restriction. As an example of the application of these values, we estimated that the observed decrease in particulate sulfate concentrations in Toronto between 1984 and 1999 resulted in annual benefits of 1.4 million dollars (95% confidence interval 0.91-1.8 million dollars) in relation to reduced emergency department visits and hospital admissions for cardiorespiratory disease.
Our approach to estimating the value of avoiding a range of acute morbidity effects of air pollution addresses a number of limitations of the current literature, and is applicable to future assessments of the benefits of improving air quality.
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The effect of fungal spores and pollen grains on morbidity from childhood conjunctivitis and rhinitis is mostly unknown. We therefore studied the association between daily concentrations of these airborne allergens and daily emergency visits to a children hospital between 1993 and 1997. An increase of 551 basidiomycetes spores per m(3), or of 72 ragweed grains per m(3), was associated with an increase of about 10% in visits for conjunctivitis and rhinitis (p
The risk of hospitalization for asthma caused by outdoor aeroallergens is largely unknown.
The objective of this study was to determine the association between changes in outdoor aeroallergens and hospitalizations for asthma from the Pacific coast to the Atlantic coast of Canada.
A daily time series analysis was done to test the association between daily changes in aeroallergens and daily changes in hospitalizations for asthma during a 7-year period between 1993 and 2000 in 10 of the largest cities in Canada. Results were adjusted for long-term trends, day of the week, climate, and air pollution.
A daily increase, equivalent to the mean value of each allergen, was associated with the following percentage increase in asthma hospitalizations: 3.3% (95% CI, 2.3 to 4.1) for basidiomycetes, 3.1% (95% CI, 2.8 to 5.7) for ascomycetes, 3.2% (95% CI, 1.6 to 4.8) for deuteromycetes, 3.0% (95% CI, 1.1 to 4.9) for weeds, 2.9% (95% CI, 0.9 to 5.0) for trees, and 2.0% (95% CI, 1.1 to 2.8) for grasses. After accounting for the independent effects of trees and ozone, the combination of the 2 was associated with an additional 0.22% increase in admissions averaged across cities (P
A comprehensive, systematic synthesis was conducted of daily time-series studies of air pollution and mortality from around the world. Estimates of effect sizes were extracted from 109 studies, from single- and multipollutant models, and by cause of death, age, and season. Random effects pooled estimates of excess all-cause mortality (single-pollutant models) associated with a change in pollutant concentration equal to the mean value among a representative group of cities were 2.0% (95% CI 1.5-2.4%) per 31.3 microg/m3 particulate matter (PM) of median diameter
The authors' purpose was to determine whether community income and education modify the effect of gaseous air pollution on respiratory hospitalizations. The authors used daily time-series analyses to test the association between daily respiratory hospitalizations and daily concentrations of ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide in 10 large Canadian cities. They calculated the percentage increase in hospitalizations for an increase in each air pollutant that was equivalent in magnitude to its mean value. The effect of nitrogen dioxide was stronger with decreasing levels of household income (p = .023). For the combined pollutant effect, percentage increases in hospitalizations ranged from 7.0% (95% confidence interval = 2.5-11.5) to -0.7% (95% confidence interval = -4.7-3.3) from lowest to highest quartile of education (trend test p = .001). Living in communities in which the individuals have lower household education and income levels may increase the individuals' vulnerability to air pollution.
Daycare attendance has been associated with an increased occurrence of respiratory illness, but little is known about which children are at particular risk. Our objectives were to determine the association between the incidence of respiratory illness and attendance in daycare, and to determine if the risk is modified by selected sociodemographic factors. Using a prospective study design, 185 newborns in Prince Edward Island, Canada, were recruited between January 1997-March 2000. They were followed for 2 years or until the end-date of the study in September 2000. Information on daycare attendance and respiratory illness was collected twice monthly by telephone interviews of the parent. Comparing those who were ever in daycare more than 1 day per week (daycare group) to those who were not, the association between daycare and illness was stronger among children 15 months of age compared to those less than 3 months of age (P or = $30,000 (P = 0.003). However, in the daycare group, income did not influence illness, with respective values of 14.6% (CI, 12.4, 16.8) vs. 13.2% (CI, 12.1, 14.3) (P = 0.21). In conclusion, younger children and those with siblings may be less susceptible to illness associated with daycare, and daycare attendance may negate a protective effect of higher income on respiratory illness.