30% higher autism risk linked to prenatal wildfire smoke
Researchers analyzing nearly 900,000 Medicaid records found a strong association between fine particle exposure after the 15th week of pregnancy and autism diagnoses.
By James Brooks ·
A new study identifies a measurable link between wildfire smoke exposure during pregnancy and the later diagnosis of autism in children. The research, published Tuesday in JAMA Pediatrics, reveals that for every 0.75 microgram per cubic meter increase in average wildfire fine particle concentration, the risk of an autism diagnosis rose by 30 percent.
Dr. Stefania Papatheodorou, an epidemiologist at the Rutgers School of Public Health and lead author of the study, explained that the data underscores the reach of wildfire pollution. She noted that smoke can travel far beyond the immediate fire zone and affect air quality even when it is not visible to the naked eye. The study utilized federal Medicaid data covering nearly 900,000 mother-child pairs enrolled in the plan from 2007 to 2014.
The team focused on particulate matter known as PM2.5, which consists of particles with diameters of 2.5 micrometers or smaller. For scale, a human hair ranges from 80 to 100 micrometers in width. The researchers determined that the association between exposure and diagnosis was strongest following the 15th week of pregnancy. Papatheodorou stated that this period coincides with rapid brain development, making it a critical window for environmental influences.
The findings are relevant to urban centers not traditionally associated with wildfire activity. In July, Philadelphia and New York faced Code Purple advisories due to smoke from Canadian fires, prompting residents to limit outdoor time. The study suggests that such events may carry implications for pregnant individuals in these regions.
The researchers emphasized that the study is observational and does not prove a direct cause-and-effect relationship. It identifies an association between higher concentrations of wildfire particles and subsequent autism diagnoses. The analysis did not find a similar link between prenatal wildfire smoke exposure and attention deficit disorder.
The data set included only mother-child pairs who remained continuously enrolled in Medicaid throughout the study period. The study aims to inform awareness of how wildfire events impact air quality during specific stages of pregnancy.
