November 27, 2013
A publication by the ESCAPE project of a study
in the Lancet Respiratory Medicine shows that exposure to ambient air
pollutants and traffic during pregnancy is associated with restricted
The study indicates that exposure to airborne pollutants during
pregnancy, even at levels below the European Air Quality Directive,
increases the risk of low birth weight.
Low birth weight, which is often defined as below 2.5 kg (5.5 lbs),
is associated with several adverse health effects later in life, such as
respiratory symptoms, impaired pulmonary function and cardiovascular
The results of the study reveal a correlation between the risk of low
birth weight and exposure to different kinds of airborne particles,
especially PM 2.5, which are created by traffic and industrial
emissions. An increase in exposure by 5 micrograms per cubic metre
corresponded with an 18 per cent increase in the risk of low birth
weight. This relationship was also observed for levels of air pollution
below the EU’s Air Quality Directive.
ESCAPE is coordinated from Utrecht University in the Netherlands and
funded through the EU’s Seventh Frame Programme (FP7). HEAL was a
partner in this research project.
Data was gathered for the study through the European Study of Cohorts
for Air Pollution Effects (ESCAPE) project, and included 14 cohort
studies from 12 European countries, giving a total of 74,000 births
between 1994 and 2011.
The study, which involves researchers from Karolinska Institutet’s
Institute of Environmental Medicine, is one of the largest of its kind.
Sweden’s contribution was the BAMSE birth cohort, which comprises babies
born in Stockholm County between 1994 and 1996.
"The results are interesting from a public health perspective too,
and the combined effects of air pollution on birth weight were of the
same order of magnitude as for smoking during pregnancy," says Professor
Göran Pershagen at the Institute of Environmental Medicine, who led the
Swedish part of the study.
The BAMSE project was set up to investigate risk factors for asthma
and allergies in children, and is run by the Institute of Environmental
Medicine at Karolinska Institutet together with the Centre for
Occupational and Environmental Medicine at the Stockholm County Council.
BAMSE has followed over 4,000 babies born between 1994 and 1996.