The number of children suffering from asthma is increasing continuously. Recent study has shown that pre-natal exposure pollution leads to some genetic changes in children which increase their risk of developing asthma.

Research team led by Dr Shuk-mei Ho, director of the Center for Environmental Genetics at the University of Cincinnati studied umbilical cord blood from 56 children. Study revealed "reprogramming" of a gene associated with exposure to compounds in traffic fumes.

Researchers studied a gene called ACSL3, which is expressed in the lung. The mothers' exposure to polycyclic aromatic hydrocarbons (PAHs) - a by-product of combustion present in high levels in heavy-traffic areas - during their pregnancy was also noted with backpack air monitors. Study showed a significant association between chemical changes which control activation of the gene and high levels of maternal PAH exposure.

Researchers said that although the finding needs to be confirmed in larger studies but changes in the ACSL3 gene may be help early diagnosis of pollution-related asthma.                                      Dr Shuk-mei Ho said: "Our data support the concept that environmental exposures can interact with genes during key developmental periods to trigger disease onset later in life, and that tissues are being reprogrammed to become abnormal later."