New Delhi, Sep 23 (IANS): In a first, researchers have linked exposure to air pollutants like particulate matter PM2.5 -- particularly in the first five years of life starting from the womb -- and alterations in the brain structure that may put children at psychiatric and cognitive disorder risks later in life.

Experts assessed children's exposure to air pollution from conception to 8.5 years of age on a monthly basis.

The study, published in the peer-reviewed journal Environmental Pollution, found an association in children aged 9-12, between exposure to air pollutants in the womb and during the first 8.5 years of life and alterations in white matter structural connectivity in the brain.

The greater the child's exposure before age five, the greater the brain structure alteration observed in preadolescence, according to the team led by the Barcelona Institute for Global Health (ISGlobal).

"The novel aspect of the present study is that it identified periods of susceptibility to air pollution. We measured exposure using a finer time scale by analysing the data on a month-by-month basis, unlike previous studies in which data was analysed for trimesters of pregnancy or childhood years," said Anne-Claire Binter, ISGlobal researcher and first author of the study.

In this study, "we analysed the children's exposure to air pollution from conception to 8.5 years of age on a monthly basis", Binter added.

In addition to the association between air pollution and white matter microstructure, the study also found a link between specific exposure to fine particulate matter (PM2.5) and the volume of the "putamen", a brain structure involved in motor function, learning processes and many other functions.

Abnormal white matter microstructure has been associated with psychiatric disorders (depressive symptoms, anxiety and autism spectrum disorders).

The study found that the greater the exposure to PM2.5, especially during the first two years of life, the greater the volume of the putamen in preadolescence.

"A larger putamen has been associated with certain psychiatric disorders (schizophrenia, autism spectrum disorders, and obsessive-compulsive spectrum disorders)," said Binter.

The data analysed came from a large cohort of 3,515 children enrolled in the Generation R Study in Rotterdam (the Netherlands).

"One of the important conclusions of this study is that the infant's brain is particularly susceptible to the effects of air pollution not only during pregnancy, as has been shown in earlier studies, but also during childhood," the researchers noted.

"We should follow up and continue to measure the same parameters in this cohort to investigate the possible long-term effects on the brain of exposure to air pollution" added Monica Guxens, ISGlobal researcher and another author of the study.