Respiratory health and individual estimated exposure to traffic-related air pollutants in a cohort of young children

Objectives: To estimate long-term exposure to traffic-related air
pollutants on an individual basis and to assess adverse health
effects using a combination of air pollution measurement data, data
from geographical information systems (GIS) and questionnaire
data.Methods: 40 measurement sites in the city of Munich, Germany
were selected at which to collect particulate matter with a 50%
cut-off aerodynamic diameter of 2.5 µm (PM2.5) and to measure PM2.5
absorbance and nitrogen dioxide (NO2). A pool of GIS variables
(information about street length, household and population density
and land use) was collected for the Munich metropolitan area and
was used in multiple linear regression models to predict
traffic-related air pollutants. These models were also applied to
the birth addresses of two birth cohorts (German Infant Nutritional
Intervention Study (GINI) and Influence of Life-style factors on
the development of the Immune System and Allergies in East and West
Germany (LISA)) in the Munich metropolitan area. Associations
between air pollution concentrations at birth address and 1-year
and 2-year incidences of respiratory symptoms were
analysed.Results: The following means for the estimated exposures
to PM2.5, PM2.5 absorbance and NO2 were obtained: 12.8
\textgreekmg/m3, 1.7×10-5 m-1 and 35.3 \textgreekmg/m3,
respectively. Adjusted odds ratios (ORs) for wheezing, cough
without infection, dry cough at night, bronchial asthma, bronchitis
and respiratory infections indicated positive associations with
traffic-related air pollutants. After controlling for individual
confounders, significant associations were found between the
pollutant PM2.5 and sneezing, runny/stuffed nose during the first
year of life (OR 1.16, 95% confidence interval 1.01 to 1.34)
Similar effects were observed for the second year of life. These
findings are similar to those from our previous analysis that were
restricted to a subcohort in Munich city. The extended study also
showed significant effects for sneezing, running/stuffed nose.
Additionally, significant associations were found between NO2 and
dry cough at night (or bronchitis) during the first year of life.
The variable ``living close to major roads'' (