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ALVA - Air Pollution and Life
Threatening Ventricular Arrhythmia.
Several studies in the last decade
have confirmed that daily variations in ambient air pollution levels are
associated with daily variations in hospital admissions as well as mortality.
Recent studies have shown that the effect per unit is at least as strong at low
levels as in the high level range and if these results can be confirmed there is
a high potential for significantly improving public health by reducing air
pollution in Swedish cities. It is however still unclear in which population
segments the health improvements can be made by reducing pollution levels if the
effect persist at the relatively low air pollution levels seen in the Swedish
cities. One study of patients with Implanted Cardioverter Defibrillators (ICD)
has suggested an association between daily variations in air pollution and
ventricular arrhythmia, which could be a possible explanation to the biological
mechanisms behind the observed associations. The study is however small and has
limited information about the study subjects which makes the results somewhat
difficult to interpret.
The aim of the proposed study is
to analyze the relation between daily variations in air pollution levels and the
risk for ventricular arrhythmia, in patients with a high enough risk for
arrhythmia to have an implanted defibrillator.
The association will be studied
with the case-crossover methodology that makes it possible to compare, for each
subject, the air pollution levels in the time period immediately preceding an
arrhythmia ("case-period") to the levels in "control-periods"
when the subject did not have an arrhythmia. The study subject will be recruited
from Stockholm, Gothenburg and Malmö and will be followed for 24 months. All
subjects will answer questionnaires on background and lifestyle factors as well
as factors relevant to their air pollution exposure. The subjects are instructed
to contact an assigned employee at their own cardiology clinic after each
ICD-discharge, to answer questions on the time period preceding the arrhythmia.
This is to provide information helpful to determine the air pollution exposure
in the "case-period" as well as information on other factors that can
cause arrhythmia. For each discharge of the ICD-device we will be able to
download information on time, arrhythmia type and intervention type. Daily
levels of PM10, PM2,5, CO, NO2, SO2
and O3 are obtained from the local Environment and Health Protection
Administrations and weather parameters that might be important to the exposure
will be provided by the National Meteorological Institute. Having information on
the ICD-discharges and air pollution and weather data we will have opportunity
to find a possible relation between episodes of high pollution levels and the
risk for ventricular arrhythmia. The results from the study will be published in
the scientific literature and presented at scientific conferences
internationally as well as in Sweden.
| Participants: |
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| Tom Bellander, PhD |
Dept. of Occupational and
Environmental Health, Stockholm County Council |
| Göran Pershagen, MD, PhD |
Institute for Environmental
Medicine, Karolinska Institutet |
| Niklas Berglind, MSc |
Dept. of Occupational and
Environmental Health, Stockholm County Council |
| Fredrik Gadler, MD |
Cardiology Clinic, Karolinska
Hospital |
| Bengt Sjögren, MD, PhD |
National Institute for Working
Life |
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Progress
report 2003 |
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