Children born to mothers who were abused during childhood are more likely to be diagnosed with autism, a new study from Harvard School of Public Health (HSPH) found. The risk of an autism diagnosis of the child is three times higher when the mother has had a history of serious abuse as a kid.
"Our study identifies a completely new risk factor for autism. Further research to understand how a woman's experience of abuse is associated with autism in her children may help us better understand the causes of autism and identify preventable risk factors," said Andrea Roberts, research associate in the HSPH Department of Social and Behavioral Sciences and lead author of the study.
Autism spectrum disorder (ASD) is a group of complex neurodevelopment disorders, characterized by social and communication difficulties along with repetitive behaviors, says the National Institute of Neurological Disorders and Stroke.
A recent Centers for Disease Control (CDC) study had shown that in the U.S., about one in every 50 children has ASD.
The present study included data from 50,000 women who were part of the Nurses' Health Study II. Researchers found that women experiencing moderate to severe abuse had a risk of having children with ASD. Women who were in the top 25 percent of those who reported severe abuse were 60 percent more likely to have a child with ASD when compared to women who had no such abuse history.
Previous research on abuse during childhood has shown that abuse can cause several chronic diseases like diabetes, heart disease and certain cancers. Effects of trauma faced in childhood stays on in later life due to the changes in immune response and increased levels of stress factors. In women, child abuse can lead to early or late menarche.
Researchers in the present study showed that child abuse doesn't just affect a single person, but also affects the next generation.
The study team then looked at the other possible risk factors that increase the chance of a woman giving birth to a child with autism. Study results showed that though women who were abused had other risk factors associated with autism diagnosis in children, these accounted for just 7 percent of the chance of a child being born with autism. Researchers say that the abuse during childhood alters certain biological mechanisms that may explain the increased risk of autism in the children of these women.
"Childhood abuse is associated with a wide array of health problems in the person who experiences it, including both mental health outcomes like depression and anxiety, and physical health outcomes like obesity and lung disease. Our research suggests that the effects of childhood abuse may also reach across generations," said Marc Weisskopf, associate professor of environmental and occupational epidemiology at HSPH and senior author of the study, according to a news release.
The study is published in the journal JAMA Psychiatry.