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BARCELONA, Spain — Exposure to air pollution during pregnancy and in early childhood can significantly alter a kid’s brain size and structure, finds a new study from Spain. Air pollution impacted brain connections in children the most in the first 8.5 years, although children before age five experienced the greatest changes.

Scientists from the Barcelona Institute for Global Health (ISGlobal) add to the idea that the infant brain is vulnerable to air pollution not only during pregnancy, but during childhood as well.

“The novel aspect of the present study is that it identified periods of susceptibility to air pollution,” says study lead author Anne-Claire Binter, an ISGlobal researcher and lead author of the study, in a statement. “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. In this study, we analysed the children’s exposure to air pollution from conception to 8.5 years of age on a monthly basis.”

There are billions of active connections with tracts of white matter in the brain ensuring structural connectivity to multiple brain areas. White matter areas connect brain regions together and are involved in higher-level cognitive processes such as learning and problem-solving, making it a common site to study brain development. Past research has linked abnormal changes in white matter structures to symptoms of depression, anxiety, and autism spectrum disorder.

In the current study, the team analyzed data from 3,515 children enrolled in a separate study from the Netherlands. Researchers estimated every child’s exposure to daily levels of nitrogen dioxide and particulate matter at their home during their mother’s pregnancy and until they reached 8.5 years of age. When children were 9 to 12, they underwent MRI brain scans to look at structural connectivity and the volume of various brain structures.

Higher levels of air pollution was associated with changes to white matter microstructures in the children’s brains. Exposure to fine particulate matter affected the volume of the putamen, a brain area involved in motor function, learning, among other essential functions. The more a child was exposed to fine particulate matter, especially in the first two years of life, the bigger the size of the putamen in preadolescence.

“A larger putamen has been associated with certain psychiatric disorders (schizophrenia, autism spectrum disorders, and obsessive-compulsive spectrum disorders),” says Binter. “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” adds Mònica Guxens, ISGlobal researcher and senior study author.

The study is published in the journal Environmental Pollution.

About Jocelyn Solis-Moreira

Jocelyn is a New York-based science journalist whose work has appeared in Discover Magazine, Health, and Live Science, among other publications. She holds a Master's of Science in Psychology with a concentration in behavioral neuroscience and a Bachelor's of Science in integrative neuroscience from Binghamton University. Jocelyn has reported on several medical and science topics ranging from coronavirus news to the latest findings in women's health.

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