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Thursday, August 22, 2013

More Risk Factors

Most scientific studies are careful to distinguish correlation and causation, but a casual reader of the news might scan recent stories and conclude that "everything causes autism."

From Time:
More research finds a family-based risk of autism among siblings, which raises the question of what parents can do to lower the risk among potentially at-risk youngsters.
Researchers from Aarhus University in Denmark report in the journal JAMA Pediatrics that children with an older brother or sister diagnosed with an autism spectrum disorder (ASD) are more likely to be on the spectrum themselves.
According to their study of about 1.5 million children born in Denmark between 1980 and 2004, those who had an older sibling diagnosed with autism had close to a seven-fold increased risk of developing autism as well. Siblings who shared the same mother and father had a 7.5 greater risk of having autism, whereas maternal half siblings had a 2.4 greater risk. Paternal half siblings didn’t have a statistically significant increase in risk.
From Healthline:
Expectant mothers should be tested for thyroid issues to reduce their child’s risk of developing autism and other complications, experts say.

New research published in the Annals of Neurology shows that mothers with low levels of the thyroid hormone T4, or throxine, are four times more likely to give birth to a child with autism. The more throxine deficient a mother is, the more pronounced her child’s symptoms can be, researchers said.

Scientists from the Houston Methodist Neurological Institute and Erasmus Medical Centre came to this conclusion after studying 4,000 Dutch mothers and their children. This finding coincides with previous research that shows a mother’s throxine levels influence a child’s neurological development.
“It is increasingly apparent to us that autism is caused by environmental factors in most cases, not by genetics,” lead author Dr. Gustavo Rom├ín, a neurologist and neuroepidemiologist who directs the Nantz National Alzheimer Center, said in a press release. “That gives me hope that prevention is possible.”
HealthDayNews reports:
Inducing or helping along labor in pregnant women may raise the risk for having a child with autism, particularly if that child is a boy, a new study suggests.
Experts, including the Duke University researchers, are quick to caution that there are often overriding medical reasons to induce or augment labor that should not be ignored because of any potential risk of autism.
Inducing labor involves stimulating contractions before labor has started through various means, and augmenting labor refers to the practice of helping labor progress more quickly with oxytocin (Pitocin), a drug that stimulates contractions.
... 
The new study, published online Aug. 12 in JAMA Pediatrics, is the largest to date that looks at autism risk and factors affecting labor and delivery. The findings don't prove that labor induction or augmentation cause autism, they just show an association. Exactly how labor induction could affect autism risk is unknown, but the drug oxytocin may play a role.
CBS reports: 
Other conditions during pregnancy have recently been linked to increased autism risk. An August 2012 study showed that mothers who were obese were 67 percent more likely to have children with the disorder compared to those who maintained a normal weight during pregnancy.
Taking the anti-epilepsy drug valproate has been linked to a five-fold higher risk of having a child with an autism spectrum disorder in an April 2013 study published in JAMA. Exposure to air pollution while with child was also significantly connected to higher rates of autism, a June 2013 Environmental Health Perspectives study revealed.