If children are exposed to excessive air pollution during their first year of life their risk of developing asthma, pollen allergies, and impaired respiratory function increases exponentially, a new study has shown.
However, the study, conducted under the BAMSE project, also found that genetic factors are also at play.
The BAMSE project monitored 4,000 children in Stockholm county for the study.
The researchers studied the children from birth in order to assess whether exposure to traffic pollution during their first year of life affects the risk of developing asthma and allergies. Levels of traffic exhaust were measured at the site of the home.
The results showed that the children who were exposed to high concentrations of pollutants ran a 60 per cent higher risk of suffering of persistent asthma symptoms. Respiratory function was also adversely affected, and the children were much more likely to be allergic to airborne allergens, particularly pollen.
The researchers also conducted studies to determine how the risk of developing air pollution-related allergies is influenced by genetic factors.
It was found that children carrying a variant of GSTP1 (glutathione S-transferase P1) gene, which is crucial to the body's ability to take care of air pollutants (the antioxidative system), run a greater risk of developing an allergy linked to traffic-related air pollution.
According to new analyses, variants of another 'asthma gene', TNF (tumour necrosis factor), also affect sensitivity to air pollution. Children with a particular combination of GSTP1 and TNF variants run a considerably higher risk of developing allergies.
The children studied in the BAMSE project are now 12 years old, and an on-line follow-up survey of the children and their parents has now been launched.
The answers to the survey will provide information about health, lifestyle and environmental conditions, including air pollution, during the children's lives, according to the researchers.