Harvard study links air pollution to higher cerebral palsy risk

Scientists from Harvard University in Boston have discovered that air pollution may increase the risk of giving birth to a child with cerebral palsy.

A team of scientists from Canada and the United States, led by Dr Yu Zhang from Harvard University in Boston (Massachusetts, USA), conducted extensive studies that led to significant conclusions. These studies were based on data analysis regarding almost 1.6 million mother-child pairs. All children who were the subject of the study were born on time between 2002 and 2017 in Ontario (Canada). Among them, 3,170 (0.2 per cent) were diagnosed with cerebral palsy.

The scientists conducted a detailed analysis to determine which concentrations of various air pollutants affected pregnant women. They considered weekly concentrations of fine particulate matter (PM2.5 and smaller), nitrogen oxide (NO2), and ozone (O3) at the pregnant women's residence locations. Details about the study were described in the medical journal JAMA Network Open.

The term "cerebral palsy" (CP) refers to movement and posture disorders resulting from brain damage during foetal life, during birth, or immediately after birth. This condition can be accompanied by other symptoms and disorders, such as intellectual disability (even in 52 per cent of children with CP), visual, auditory, speech, and communication disorders, behavioural disorders, and epilepsy. Cerebral palsy is considered the most common cause of disability in children.

The causes of this condition are not well understood. It is known that one risk factor for CP is preterm birth. However, three-quarters of children with this diagnosis are born on time. Therefore, it is essential to understand all the causes of cerebral palsy to apply more effective prevention measures for the disorder.

The analysis conducted by the scientists showed that the risk of giving birth to a child with cerebral palsy increased with higher exposure to delicate particulate matter. A 2.7 micrograms per cubic metre increase in PM2.5 concentration was associated with a 12 per cent increase in CP risk. This relationship was more robust in boys, where the risk increased by 14 per cent, compared to girls, where the risk increased by 8 per cent. The average PM2.5 concentration to which pregnant women (and their children during the foetal period) were exposed was 8.3 micrograms per cubic metre (from 7 to 9.7 micrograms per cubic metre).

The scientists were unable to identify any specific period during the foetal life of the children when exposure to PM2.5 was particularly associated with the risk of cerebral palsy.

The study's authors believe that these results indicate that limiting prenatal exposure to fine particulate matter (PM2.5) can reduce the risk of cerebral palsy.

They emphasise that air pollution has previously been linked to changes in brain structure, neurogenesis (the process of creating new neurons) disorders, and neurodevelopmental diseases. Therefore, further research is necessary to understand the relationship between exposure to particulate matter and the risk of CP better.