Autism Risk May Be Increased By High Pollution Levels
A new Harvard School of Public Health study found that pregnant women could be twice as likely to give birth to an autistic child if they were exposed to high levels of air pollution. Specifically, exposure to chemicals such as lead, manganese, mercury, methylene chloride and diesel particulates have been known to impact brain function and babies.
‘Our results suggest that new studies should begin the process of measuring metals and other pollutants in the blood of pregnant women or newborn children to provide stronger evidence that specific pollutants increase risk of autism. A better understanding of this can help to develop interventions to reduce pregnant women’s exposure to these pollutants,’ explained Marc Weisskopf, associate professor of environmental and occupational epidemiology at HSPH. (Source: HSPH)
The Harvard researchers looked at data from the Nurses’ Health Study II, which focused on Brigham and Women’s Hospital involving 116,430 nurses. From this very large data set, they culled out 325 women who gave birth to an autistic child. Then they identified 22,000 women from the same data that gave birth to a child that did not have autism.
For the sake of comparison, they looked at air pollution data from the U.S. Environmental Protection Agency and physical locations to determine exposure levels for the research subjects. They found that the women who lived in areas with the highest levels of diesel particulates and mercury in the air were twice as likely to give birth to an autistic child. (This study factored in other lifestyle considerations such as income, education, and smoking during pregnancy.)
For exposure to air polluted with methylene chloride, lead, manganese, and metals the autism risk was about 50% greater. Other research has indicated there could be an increased autism risk for older fathers, because as males age their sperm quality decreases. Reduced sperm quality has been linked to a greater chance of birth defects. It wasn’t reported if the new Harvard study factored in the age of the fathers that were linked to the autistic and non-autistic births.