Prenatal pollution Exposure Linked to Higher Cerebral Palsy Risk in Children: JAMA

A per interquartile range (IQR) rise in prenatal residential ambient fine particulate matter with a diameter 2.5 μm (PM2.5) concentration (2.7 μg/m3) was linked with a 1.12 times higher risk of CP, the researchers reported.

Air pollution is associated with disruption of neurogenesis, structural brain changes, and neurodevelopmental disorders. There has been no thorough investigation of the association between prenatal exposure to ambient air pollution and the risk of cerebral palsy, which is the most common motor disability in childhood.

To fill this knowledge gap, Yu Zhang, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, and colleagues aimed to evaluate the associations between prenatal residential exposure to ambient air pollution and CP risk among children born at term gestation in a population cohort in Ontario, Canada.

For this purpose, the researchers conducted a population-based cohort study in Ontario, Canada, using linked, province-wide health administrative databases. Participants included singleton full-term births (≥37 gestational weeks) born in Ontario hospitals between 2002 and 2017.

During pregnancy, maternal exposure levels to ambient fine particulate matter smaller than 2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) were assessed based on satellite-derived and ground-level monitoring data linked to maternal residence at delivery.

The cases of cerebral palsy were ascertained by a single inpatient hospitalization diagnosis or at least two outpatient diagnoses for children from birth to age 18 years.

The following were the key findings of the study:

• The study included 1,587,935 mother-child pairs who reached term gestation, among whom 0.2% of children were diagnosed with CP. The study population had a mean maternal age of 30.1 years, and 51.1% of infants were male.
• A per IQR increase (2.7 μg/m3) in prenatal ambient PM2.5 concentration was associated with a cumulative hazard ratio (CHR) of 1.12 for CP.
• The CHR in male infants (1.14) was higher compared with the CHR in female infants (1.08).
• There was no specific window of susceptibility for prenatal PM2.5 exposure and CP in the study population.
• There were no associations or windows of susceptibility for prenatal NO2 or O3 exposure and CP risk.

The findings showed that prenatal PM2.5 exposure was associated with an increased risk of cerebral palsy. The researchers found no specific window of susceptibility during pregnancy.

"There is a need for further studies to explore this association and its potential biological pathways, which could advance the identification of environmental risk factors of CP in early life," the researchers concluded.

Reference:

Zhang Y, Hu Y, Talarico R, et al. Prenatal Exposure to Ambient Air Pollution and Cerebral Palsy. JAMA Netw Open. 2024;7(7):e2420717. doi:10.1001/jamanetworkopen.2024.20717