Biomedical subjects

A Zanobetti

Publications and source records attributed to A Zanobetti.

24 records · Page 2Linked to original sources

PubMed1996

Short term effects of air pollution on health: a European approach using epidemiologic time series data: the APHEA protocol.

BACKGROUND AND OBJECTIVES: Results from several studies over the past five years have shown that the current levels of pollutants in Europe and North America have adverse short term effects on health. The APHEA project aims to quantifying these in Europe, using standardised methodology. The project protocol and analytical methodology are presented here. DESIGN: Daily time series data were gathered for several air pollutants (sulphur dioxide; particulate matter, measured as total particles or as the particle fraction with an aerodynamic diameter smaller than a certain cut off, or as black smoke; nitrogen dioxide; and ozone) and health outcomes (the total and cause specific number of deaths and emergency hospital admissions). The data included fulfilled the quality criteria set by the APHEA protocol. SETTING: Fifteen European cities from 10 different countries with a total population over 25 million. METHODOLOGY: The APHEA collaborative group decided on a specific methodological procedure to control for confounding effects and evaluate the hypothesis. At the same time there was sufficient flexibility to allow local characteristics to be taken into account. The procedure included modelling of all potential confounding factors (that is, seasonal and long term patterns, meteorological factors, day of the week, holidays, and other unusual events), choosing the "best" air pollution models, and applying diagnostic tools to check the adequacy of the models. The final analysis used autoregressive Poisson models allowing for overdispersion. Effects were reported as relative risks contrasting defined increases in the corresponding pollutant levels. Each participating group applied the analyses to their own data. CONCLUSIONS: This methodology enabled results from many different European settings to be considered collectively. It represented the best available compromise between feasibility, comparability, and local adaptibility when using aggregated time series data not originally collected for the purpose of epidemiological studies.

Air Pollutants↗

PubMed1996

Short term effects of urban air pollution on respiratory health in Milan, Italy, 1980-89.

STUDY OBJECTIVE: To investigate the association between daily urban air pollution and acute effects on respiratory health. STUDY DESIGN: Time series analysis following the procedure defined in the APHEA protocol. SETTING: City of Milan, Italy, from 1980-89. Two air pollutants, total suspended particulates (TSP) and sulphur dioxide (SO2), and two health outcomes, deaths and hospital admissions were considered. The last was analysed according to two age groups. SUBJECTS: Daily deaths and general hospital admissions for respiratory causes in residents who died in Milan or were admitted to local hospitals in that city. MAIN RESULTS: There was an increased risk of respiratory death and of hospital admission associated with increased concentrations of SO2 and TSP. The relative risks were similar for both pollutants, and were higher for respiratory deaths than for hospital admissions. No changes in relation to season were seen in the SO2 effect on respiratory deaths, but there was a suggestion of a higher effect on hospital admissions in the cool months. The seasonal pattern of the TSP effect was inconsistent: for mortality it was higher in the warm period while for hospital admissions it seemed to be higher in the cool months. This last result might be due to chance, although some role could have been played by the hospital admission data on all general admissions for respiratory causes (ICD-9: 460-519) as these are a much less specific end point. CONCLUSION: In Milan, a positive association was found between the daily SO2 or TSP concentrations and the number of deaths or hospital admissions for respiratory causes. This confirms results from other European and North American cities.

Acute Disease↗

PubMed1995

[Air pollution and daily mortality among Milan residents, 1980-89. Preliminary results].

Short term effects of air pollutant levels on daily mortality were studied, using time series approach, in Milan from the year 1980 to 1989. The Poisson regression with autocorrelated residuals was applied. This paper reports preliminary results of the analyses on the association between total daily number of deaths and the 24h mean concentrations, on the same day, for two air pollutants: sulphur dioxide and total suspended particulate. A positive and curvilinear relation (with a logarithmic shape) has been found between total daily mortality and concentration levels for each pollutant. This result confirm a steeper increase in mortality at low concentrations, lower than the international standards in use at the moment.

Air Pollutants↗

PubMed1995

[Time series analysis in environmental epidemiology: short-term effects of air pollution on mortality and morbidity].

This work gives an overview of design and analysis of temporal studies using aggregated data in air pollution epidemiology. In the last years time series are often used to study the short-term association between ambient air pollution levels and aggregated health data. Health endpoints are usually daily mortality and/or daily hospital admission data from routine health registers. Air quality data are commonly obtained from one (or a few) fixed site monitoring stations. To detect the temporal association between the time-pattern in air pollution and the time-pattern in health data particular attention needs to be given to the autocorrelation structure, to the seasonality and long term trend in the data, and to the weather variables. Poisson regression with autocorrelated residuals is the suitable statistical method to analyze time studies. Furthermore, the pollutant variable can be analyzed at different lag-times to account for short latency periods in the manifestation of diseases. Studies with temporal aggregated data show the same disadvantages of the ecologic studies, although, in this case, confounding is less of a problem. Temporal studies usually are based on a large database, so that sufficient power can be achieved to detect even weak associations. Finally, the exposure information on subjects is often better characterized by short-term fluctuations in ambient air quality than is the case in geographic aggregations.

Air Pollutants↗

PubMedDate not supplied

Air pollution and cause-specific mortality in Milan, Italy, 1980-1989.

In several studies, investigators have reported associations among air pollution, weather, and daily deaths, usually from all causes. In the current study, we focused on the difference in lag time between exposure to total suspended particulates or extreme weather and cause-specific mortality in an effort to understand the potential underlying mechanism. We used a robust Poisson regression in a generalized additive model to investigate the association between air pollution and daily mortality. We used a loess smooth function to model season, weather, and humidity; indicator variables for hot days were also used. To examine the relationship in a currently meaningful range, we excluded all days with a total suspended particulate concentration higher than 200 microg/m3. We found a significant association on the concurrent day, both for respiratory infection deaths (11% increase/100 microg/m3 increase in total suspended particulate; 95% confidence interval = 5, 17) and for heart-failure deaths (7% increase; 95% confidence interval = 3, 11). The associations with myocardial infarction (i.e., 10% increase; 95% confidence interval = 3, 18) and chronic obstructive pulmonary disease (12% increase, 95% confidence interval = 6, 17) were found for the means of 3 and 4 d prior to death. We observed an effect of cold weather at lag 1 for respiratory infections and an effect of hot weather at lag 0 for heart failure and myocardial infarctions. The association for all causes and cause-specific deaths was almost identical to that noted previously in Philadelphia, Pennsylvania. Smoothed functions of total suspended particulates suggested a higher slope at lower concentrations, and this finding may account for differences noted between European and U.S. studies. Given that both the dependence between weather and daily mortality and the lag between exposure and death varies by cause of death, analyses by specific causes of death would be very useful in the future.

Air Pollution↗

PubMedDate not supplied

[Statistical evaluation of the "measure of concordance" between Angle classifications and the ANB angle].

In a sample of 177 subjects 6 to 15 years of age, with various types and degrees of malocclusions, the A.A. measured, with statistical methods, the agreement between Angle and Ballard classifications. The result was a disagreement between the two classifications for Class I and Class II malocclusion and some agreement between the two classifications for Class III malocclusion. The applied discriminant function was not able to classify observations in a better way.

Adolescent↗