We examined the role that ambient air pollution plays in exacerbating cardiac disease by relating daily fluctuations in admissions to 134 hospitals for congestive heart failure in the elderly to daily variations in ambient concentrations of carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, and the coefficient of haze in Canada's 10 largest cities for the 11-year period 1981-1991 inclusive. We adjusted the hospitalization time series for seasonal, subseasonal, and weekly cycles and for hospital usage patterns. The logarithm of the daily high-hour ambient carbon monoxide concentration recorded on the day of admission displayed the strongest and most consistent association with hospitalization rates among the pollutants, after stratifying the time series by month of year and adjusting simultaneously for temperature, dew point, and the other ambient air pollutants. The relative risk for a change from 1 ppm to 3 ppm, the 25th and 75th percentiles of the exposure distribution, was 1.065 (95% confidence interval = 1.028-1.104). The regression coefficients of the other air pollutants were much more sensitive to simultaneous adjustment for either multiple pollutant or weather model specifications.
This study examines the relationship of asthma emergency department (ED) visits to daily concentrations of ozone and other air pollutants in Saint John, New Brunswick, Canada. Data on ED visits with a presenting complaint of asthma (n = 1987) were abstracted for the period 1984-1992 (May-September). Air pollution variables included ozone, sulfur dioxide, nitrogen dioxide, sulfate, and total suspended particulate (TSP); weather variables included temperature, humidex, dewpoint, and relative humidity. Daily ED visit frequencies were filtered to remove day of the week and long wave trends, and filtered values were regressed on air pollution and weather variables for the same day and the 3 previous days. The mean daily 1-hr maximum ozone concentration during the study period was 41.6 ppb. A positive, statistically significant (p
Cites: J Air Pollut Control Assoc. 1981 Mar;31(3):236-407229222
The effects of tropospheric ozone on lung function and respiratory symptoms have been well documented at relatively high concentrations. However, previous investigations have failed to establish a clear association between tropospheric ozone and respiratory diseases severe enough to require hospitalization after controlling for climate, and with gaseous and particulate air pollution at the lower concentrations typically observed in Canada today. To determine if low levels of tropospheric ozone contribute to hospitalization for respiratory disease, air pollution data were compared to hospital admissions for 16 cities across Canada representing 12.6 million people. During the 3927-day period from April 1, 1981, to December 31, 1991, there were 720,519 admissions for which the principle diagnosis was a respiratory disease. After controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, soiling index, and dew point temperature, the daily high hour concentration of ozone recorded 1 day previous to the date of admission was positively associated with respiratory admissions in the April to December period but not in the winter months. The relative risk for a 30 ppb increase in ozone varied from 1.043 (P
The association of daily cardiac and respiratory admissions to 168 acute care hospitals in Ontario, Canada, with daily levels of particulate sulfates was examined over the 6-year period 1983-1988. Sulfate levels were recorded at nine monitoring stations in regions of southern and central Ontario spanned by three monitoring networks. A 13-micrograms/m3 increase in sulfates recorded on the day prior to admission (the 95th percentile) was associated with a 3.7% (p
The authors investigated the association between daily variations in ozone and cause-specific mortality. Fixed-site air pollution monitors in Montreal, Quebec, provided daily mean levels of ozone, particles, and other gaseous pollutants. Information on the date and underlying cause of death was obtained for residents of Montreal who died in the city between 1984 and 1993. The authors regressed the logarithm of daily counts of cause-specific mortality on mean levels of ozone, after accounting for seasonal and subseasonal fluctuations in the mortality time series, non-Poisson dispersion, and weather variables. The effect of ozone on mortality was generally higher in the warm season and among persons aged 65 years or over. For an increase in the 3-day running mean concentration of ozone of 21.3 microg/m(3), the percentage of increase in daily deaths in the warm season was the following: nonaccidental deaths, 3.3% (95% confidence interval (CI): 1.7, 5.0); cancer, 3.9% (95% CI: 1.0, 6.91); cardiovascular diseases, 2.5% (95% CI: 0.2, 5.0); and respiratory diseases, 6.6% (95% CI: 1.8, 11.8). These results were independent of the effects of other pollutants and were consistent with a log-linear response function.
Assess associations between short-term exposure to gaseous pollutants and asthma hospitalisation among boys and girls 6 to12 years of age.
A bi-directional case-crossover analysis was used. Conditional logistic regression models were fitted to the data for boys and girls separately. Exposures averaged over periods ranging from one to seven days were used to assess the effects of gaseous pollutants on asthma hospitalisation. Estimated relative risks for asthma hospitalisation were calculated for an incremental exposure corresponding to the interquartile range in pollutant levels, adjusted for daily weather conditions and concomitant exposure to particulate matter.
Toronto, Ontario, Canada.
A total of 7319 asthma hospitalisations for children 6 to 12 years of age (4629 for boys and 2690 for girls) in Toronto between 1981 and 1993.
A significant acute effect of carbon monoxide on asthma hospitalisation was found in boys, and sulphur dioxide showed significant effects of prolonged exposure in girls. Nitrogen dioxide was positively associated with asthma admissions in both sexes. The lag time for certain gaseous pollutant effects seemed to be shorter in boys (around two to three days for carbon monoxide and nitrogen dioxide), as compared with girls (about six to seven days for sulphur dioxide and nitrogen dioxide). The effects of gaseous pollutants on asthma hospitalisation remained after adjustment of particulate matter. The data showed no association between ozone and asthma hospitalisation in children.
The study showed positive relations between gaseous pollutants (carbon monoxide, sulphur dioxide, and nitrogen dioxide) at comparatively low levels and asthma hospitalisation in children, using bi-directional case-crossover analyses. Though, the effects of certain specific gaseous pollutants were found to vary in boys and girls.
Cites: Environ Res. 1994 Oct;67(1):1-197925191
Cites: Environ Res. 1994 Apr;65(1):56-688162885
Cites: N Engl J Med. 1995 Jan 19;332(3):133-87800004
Cites: Environ Health Perspect. 1995 Mar;103 Suppl 2:97-1027614954
Cites: Epidemiology. 1995 Sep;6(5):476-848562622
Cites: Thorax. 1995 Oct;50(10):1051-67491552
Cites: Thorax. 1995 Sep;50(9):948-548539674
Cites: Thorax. 1995 Nov;50(11):1188-938553276
Cites: Thorax. 1996 Jan;51 Suppl 1:S3-68658385
Cites: Thorax. 1996 Jan;51(1):13-228658362
Cites: J Epidemiol Community Health. 1996 Apr;50 Suppl 1:S3-118758217
Cites: J Epidemiol Community Health. 1996 Apr;50 Suppl 1:s22-98758220
Cites: J Epidemiol Community Health. 1996 Apr;50 Suppl 1:s42-68758223
Cites: J Epidemiol Community Health. 1996 Apr;50 Suppl 1:s63-708758227
Cites: J Epidemiol Community Health. 1996 Apr;50 Suppl 1:s71-58758228
Cites: Environ Health Perspect. 1996 Dec;104(12):1354-609118879
Cites: Environ Health Perspect. 1997 Feb;105(2):216-229105797
Cites: Epidemiology. 1997 Mar;8(2):162-79229208
Cites: Thorax. 1997 Sep;52(9):760-59371204
Cites: J Expo Anal Environ Epidemiol. 1998 Apr-Jun;8(2):129-449577746
Cites: Biometrics. 1998 Jun;54(2):596-6059629646
Cites: J Air Waste Manag Assoc. 1998 Aug;48(8):689-7009739623
Cites: Am J Public Health. 1998 Dec;88(12):1761-69842371
Cites: Epidemiology. 1999 Jan;10(1):23-309888276
Cites: Health Rep. 1998 Winter;10(3):9-21 (ENG); 9-22 (FRE)9926344
Cites: Arch Environ Health. 1999 Mar-Apr;54(2):130-910094292
Cites: Environ Health Perspect. 1999 Jun;107(6):489-9310339450
Cites: Environ Health Perspect. 1999 Jun;107 Suppl 3:421-910423388
Cites: Environ Health Perspect. 1999 Aug;107(8):629-3110417359
Cites: Environ Health Perspect. 1999 Aug;107(8):633-610417360
Determine the risk of premature mortality due to the urban ambient air pollution mix in Canada.
The number of daily deaths for non-accidental causes were obtained in 11 cities from 1980 to 1991 and linked to concentrations of ambient gaseous air pollutants using relative risk regression models for longitudinal count data.
Nitrogen dioxide had the largest effect on mortality with a 4.1% increased risk (p
Comment In: Can J Public Health. 1998 Jul-Aug;89(4):228, 238, 240 passim9735513
To investigate the acute respiratory health effects of ambient air pollution, the number of emergency of urgent daily respiratory admissions to 168 acute care hospitals in Ontario were related to estimates of exposure to ozone and sulfates in the vicinity of each hospital. Ozone levels were obtained from 22 monitoring stations maintained by the Ontario Ministry of the Environment for the period January 1, 1983 to December 31, 1988. Daily levels of sulfates were recorded at nine monitoring stations representing three different networks operated by the Ontario Ministry of the Environment and Environment Canada. Positive and statistically significant associations were found between hospital admissions and both ozone and sulfates recorded on the day of admission and up to 3 days prior to the date of admission. Five percent of daily respiratory admissions in the months of May to August were associated with ozone, with sulfates accounting for an additional 1% of these admissions. Ozone was a stronger predictor of admissions than sulfates. Positive and statistically significant (P
The association between daily fluctuations in ambient particulate matter and daily variations in nonaccidental mortality have been extensively investigated. Although it is now widely recognized that such an association exists, the form of the concentration-response model is still in question. Linear, no threshold and linear threshold models have been most commonly examined. In this paper we considered methods to detect and estimate threshold concentrations using time series data of daily mortality rates and air pollution concentrations. Because exposure is measured with error, we also considered the influence of measurement error in distinguishing between these two completing model specifications. The methods were illustrated on a 15-year daily time series of nonaccidental mortality and particulate air pollution data in Toronto, Canada. Nonparametric smoothed representations of the association between mortality and air pollution were adequate to graphically distinguish between these two forms. Weighted nonlinear regression methods for relative risk models were adequate to give nearly unbiased estimates of threshold concentrations even under conditions of extreme exposure measurement error. The uncertainty in the threshold estimates increased with the degree of exposure error. Regression models incorporating threshold concentrations could be clearly distinguished from linear relative risk models in the presence of exposure measurement error. The assumption of a linear model given that a threshold model was the correct form usually resulted in overestimates in the number of averted premature deaths, except for low threshold concentrations and large measurement error.
Recent studies suggest that persons with congestive heart failure (CHF) may be at higher risk for short-term effects of air pollution. This daily diary panel study in Montreal, Quebec, was carried out to determine whether oxygen saturation and pulse rate were associated with selected personal factors, weather conditions and air pollution.
Thirty-one subjects with CHF participated in this study in 2002 and 2003. Over a 2-month period, the investigators measured their oxygen saturation, pulse rate, weight and temperature each morning and recorded these and other data in a daily diary. Air pollution and weather conditions were obtained from fixed-site monitoring stations. The study made use of mixed regression models, adjusting for within-subject serial correlation and temporal trends, to determine the association between oxygen saturation and pulse rate and personal and environmental variables. Depending on the model, we accounted for the effects of a variety of personal variables (eg, body temperature, salt consumption) as well as nitrogen dioxide (NO2), ozone, maximum temperature and change in barometric pressure at 8:00 from the previous day.
In multivariable analyses, the study found that oxygen saturation was reduced when subjects reported that they were ill, consumed salt, or drank liquids on the previous day and had higher body temperatures on the concurrent day (only the latter was statistically significant). Relative humidity and decreased atmospheric pressure from the previous day were associated with oxygen saturation. In univariate analyses, there was negative associations with concentrations of fine particulates, ozone, and sulphur dioxide (SO2), but only SO2 was significant after adjustment for the effects of weather. For pulse rate, no associations were found for the personal variables and in univariate analyses the study found positive associations with NO(2), fine particulates (aerodynamic diameter of 2.5 microm or under, PM(2.5)), SO2, and maximum temperature, although only the latter two were significant after adjustment for environmental effects.
The findings from the present investigation suggest that personal and environmental conditions affect intermediate physiological parameters that may affect the health of CHF patients.